INVASIVE SPECIES IN ECOLOGICAL HABITATS OF NATIONAL PARKS IN BHUTAN

“INVASIVE SPECIES IN

Submitted in partial fulfilment of the requirement for the degree of

Dr. NAWA BAHARDr. NAWA BAHARDr. NAWA BAHARDr. NAWA BAHAR

Scientist C, Silviculture

Forest Research Institute, Dehradun.

Forest Research Institute (Deemed) University

INDIAN COUNCIL OF FORESTRY RESEARCH AND

INVASIVE SPECIES IN ECOLOGICAL HABITATS OF NATIONAL

PARKS IN BHUTAN”

UGYEN DORJI


M.SC. FORESTRY

(2012-2014)

Under the guidance of

Dr. NAWA BAHARDr. NAWA BAHARDr. NAWA BAHARDr. NAWA BAHAR

Scientist C, Silviculture Division,

Forest Research Institute, Dehradun.

Forest Research Institute (Deemed) University,


EDUCATION

OF NATIONAL


, Dehradun


Table of Contents

INTRODUCTION ............................................................................................................................................... 1

BHUTAN ........................................................................................................................................................... 2

1. THE GREAT HIMALAYA................................................................................................................................... 3

2. THE INNER HIMALAYA .................................................................................................................................... 3

DRAINAGE/RIVER SYSTEM .................................................................................................................................. 3

METEOROLOGY ................................................................................................................................................... 4

BIODIVERSITY OF BHUTAN ............................................................................................................................... 5

IMPORTANCE OF BIODIVERSITY .......................................................................................................................... 5

FORESTRY IN BHUTAN ..................................................................................................................................... 7

THREATS AND CHALLENGES................................................................................................................................ 8

INVASIVE SPECIES ............................................................................................................................................ 9

PHASE OF BIOLOGICAL INVASION IN BHUTAN ..................................................................................................... 9

INVASIVE SPECIES FOUND IN BHUTAN AND THEIR COMMON NAMES .................................................................. 10

PROTECTED AREAS IN BHUTAN ...................................................................................................................... 19

INVASIVE SPECIES IN PROTECTED AREAS .......................................................................................................... 20

COMMON INVASIVE SPECIES IN DIFFERENT ECOLOGICAL HABITATS OF PROTECTED AREAS ..................................................... 21

COMMON INVASIVE SPECIES IN ECOLOGICAL HABITATS OF NATIONAL PARKS .............................................. 30

JIGME DORJI NATIONAL PARK .................................................................................................................................. 30

JIGME SINGYE WANGCHUCK NATIONAL PARK ............................................................................................................. 32

ROYAL MANAS NATIONAL PARK............................................................................................................................... 34

WANGCHUCK CENTENNIAL PARK.............................................................................................................................. 38

COMMON INVASIVE SPECIES IN ECOLOGICAL HABITATS OF SANCTUARIES ................................................... 40

BOMDELING WILDLIFE SANCTUARY ........................................................................................................................... 40

KHALING NEOLI WILDLIFE SANCTUARY ...................................................................................................................... 42

PHIPSOO WILDLIFE SANCTUARY ............................................................................................................................... 43

SAKTENG WILDLIFE SANCTUARY ............................................................................................................................... 45

TORSA STRICT NATURE RESERVE .............................................................................................................................. 46

FACTORS LEADING TO INTRODUCTION AND SPREAD OF INVASIVE SPECIES .................................................. 47

IMPACTS OF INVASIVE SPECIES ...................................................................................................................... 49

STATUS OF STUDY AND IMPLEMENTATION PROGRAMS IN BHUTAN ............................................................. 49

CONCLUSION ................................................................................................................................................. 50

REFERENCES ................................................................................................................................................... 51

1

Introduction

The Kingdom of Bhutan is a small southern Asian country. It is a landlocked country, bounded by

India in South, East and South-West and Tibetan autonomous region of China in the North and North-

West subsequently. It is about 300 km long and 150 km wide encompassing an area of 46,500 square

kilometres. Virtually, the entire country is almost mountainous, and ranges in elevation as low as 97m

along the Indian border to as high as 7,554m peak on the Tibetan border. These two extremes frame a

landscape which stretches from sub-tropical to arctic like alpine conditions and making the country

distinctively divisible into three lateral zones from South to North: Subtropical zone (100m-1200m),

Temperate zone (1200m-4000m) and Alpine zone (above 4000m).

One of Bhutan's significant natural resources in the late twentieth century is its rich forests and natural

vegetation. Bhutan straddles two major biogeographic realms, the Indo-Malayan and Palearctic and is

part of the eastern Himalayan region which contains parts of three global biodiversity hotspots, 60

ecoregions, 330 important bird areas, 53 important plant areas, and a large number of wetlands and 29

Ramsar sites. Today, the country has 70.46 percent of the total area under forest cover and 51.32

percent, secured as protected areas and biological corridors. The protected area system of Bhutan is

regarded as one of the most comprehensive in the world. It encompasses a continuum of

representational samples of all major ecosystems found in the country, ranging from the sub-tropical

grasslands and forests in the southern foothills through temperate forests in the central mountains and

valleys to alpine meadows in the northern mountains. Protected areas of Bhutan is home to a diverse

array of flora and fauna including 5603 species of vascular plants, 400 lichens, 200 mammals and

about 700 birds. In addition to the currently known 105 endemic plant species, Bhutan also hosts a

number of globally threatened species including 27 mammals and 18 birds. Today, however, the rich

biodiversity of the country is in the verge of decreasing in number.

In Bhutan, loss of biodiversity is caused by several factors such as changes in land use, over

exploitation of natural resources, destruction of natural habitats, urbanization, human wildlife conflict,

forest fires, hydropower development, industrial development and one of the important factor includes

introduction of invasive alien species in the country. The introduction of invasive species has also

caused decline to economic status, environmental harm and harm to human health. Accordingly, the

governmental organizations and non-governmental organizations in the country are working hard to

alleviate these factors and come to proper solutions.

The study of invasive species, finding approximate number and their effect are under process. There

are over 200 invasive species including both plants and animals in the country, belonging mostly to

Compostae and Graminae families. However, the knowledge of invasive are new to Bhutan due to

which, currently a very few numbers of works are done to study it and essential mitigation activities

against it. If such trends, where people are less aware and have limited knowledge, and again if

detailed studies on invasive species are not soon being carried out, consequently, invasive species can

bring greater harm to the biodiversity, the local communities and the country as a whole.

Thus the present work is an attempt to reveal the country’s biodiversity and vegetational zones and

study the invasive species found in the country with particular focus on those invasive species found

in the ecological habitats of national parks of Bhutan.

2

Bhutan

The Kingdom of Bhutan is located in Southern Asia. It is a landlocked country, sandwiched between

China to the north and India to the south. It is about 300 km long and 150 km wide encompassing an

area of 46,500 square kilometres. Located between longitude 880 45' and 92010' East and latitudes 260

40' and 280 15' North in the Eastern Himalayas, it is bounded by India in South, East and South-West

and Tibetan autonomous region of China in the North and North-West respectively ("Geography of

Bhutan,"2012).

Virtually, the entire country is almost mountainous, and ranges in elevation from 97m Drangme chhu1

along the Indian border to the 7,554m Kula Gangri 2peak on the Tibetan border. These two extremes

frame a landscape which stretches from sub-tropical to arctic like alpine conditions. The maximum

East-West stretch of the country is approximately 300 km and north-South about 150 km (Rosenberg,

2005).

Figure 1. Location of Bhutan, showing Chinese and Indian borders to north and south respectively

("Geography of Bhutan," 2012).

Physiography

Bhutan is distinctively divisible into three lateral zones from South to North. Incidentally, this

zonation is more or less applicable to meteorological, ethnographical and geographical divisions of

the country. Thus, the climatic zones are also divisible into three lateral zones, Subtropical zone

(100m-1200m), Temperate zone (1200m-4000m) and Alpine zone (above 4000m).

1Drangme Chhu is one of the rivers in Bhutan, considered as lowest point of elevation.

2 Kula Kangri is claimed by many authorities to be the highest mountain in Bhutan but this is disputed by others, who claim that Kula Kangri is wholly in Tibet.

3

Talking in geomorphologic terms, Bhutan is distinctively divisible into three lateral zones from South

to North, as addressed below:

1. The Great Himalaya

Extending from Mt. Jhomolhari (7,314m) in the West to Kulha Gangri (7,554m) near the center point

of the northern border between Tibet and Bhutan, this region is virtually a snow-wilderness zone

where almost 20% of the land is under perpetual snow. This region consists of an arc of glaciated

mountain peaks with an arctic climate at the highest elevations. Watered by snow-fed rivers, alpine

valleys in this region provide pasture for livestock of a sparse population of migratory shepherds

(Congress, 2011). This zone is represented by alpine meadows and perpetually snow bound high

summit of the Great Himalayan range.

2. The Inner Himalaya This is the largest physiographic region of Bhutan and lies among broad valleys and forested hillsides

from 1,100m to 3,000m in elevation. All the major towns of Bhutan are situated in this zone such as

Paro, Thimphu, Punakha, in western Bhutan, Trongsa and Bumthang in central Bhutan and Mongar,

Trashigang in eastern Bhutan ("Geography of Bhutan," 2012). The Inner Himalayas are southward

spurs of the Great Himalayan Range. The Black Mountains, in central Bhutan, form a watershed

between two major river systems, the Mo Chhu 3and the Drangme Chhu. Peaks in the Black

Mountains range between 1,500 meters and 2,700 meters above sea level, and the fast-flowing rivers

have carved out spectacular gorges in the lower mountain areas. The woodlands of the central region

provide most of Bhutan's valuable forest production. Eastern Bhutan is divided by another southward

spur, the Donga Range. Western Bhutan has fertile, cultivated valleys and terraced river basins

(Congress, 2011).

3. The Southern foothills

Also called as Himalayan foothills, this zone occupies the southernmost part of the country. The

plains in the south of the country are part of the region known as Terai, which extends from Kashmir,

through Nepal, to Bhutan. The average annual rainfall in this region generally reaches up to 200

inches resulting to luxuriant vegetation particularly tropical forests rich in wildlife, while at times hot,

steamy and unhealthy tracts are other features of this zone ("Geography of Bhutan," 2012).

Drainage/River system

Rivers play an important role in Bhutan's physical, economic, social and cultural geography. Their

enormous potential for hydroelectric power has helped in shaping the national economy. Since the

central Himalayas of Bhutan receives the full brunt of the monsoon so the rivers are larger and have

created much broader valleys than rivers further to the west in Nepal and India. In their upper reaches,

most Bhutanese rivers have created large fertile valleys. As the rivers pass through the centre of

Bhutan, the valleys become steeper and narrower, and roads have to climb high on the hillside

("Geography of Bhutan," 2012).The principal rivers of the country are; Amo chhu, Paro Chhu, Wang

Chhu, Punatsang Chhu, Mangde Chhu, Pho Chhu, Mo Chhu, Dangme Chhu, Manas Chhu and

Chamkhar Chhu.

3 One of the important rivers of Bhutan, Chhu means river.

4

Meteorology Bhutan's climate varies widely depending upon elevation. In the southern region it is tropical, with a

monsoon season and eastern part is warmer than the west. The central valley, which includes districts

like Wangdue Phodrang and Punakha enjoys a semi-tropical climate with cool winters, whereas Paro,

Thimphu, Trongsa and Bumthang have relatively harsher climate including snowfall in winter

(Rosenberg, 2005).

Figure 2. Map showing central valleys and major river systems of Bhutan("Map of Bhutan," 2011).

Spring lasts from mid-March to the beginning of June, with temperatures warming gradually to 27-29 degree centigrade by day and about 18 degree centigrade at night ("Geography of Bhutan," 2012). However, cold spells are possible up until the end of April, with a chance of new snow on the mountains above the valleys. Strong, gusty winds start blowing almost every day from noon to early evening. The first storms break, and they become more and more frequent with the approach of the monsoon which arrives in mid-June (Rosenberg, 2005).

The country receives abundant rain especially in the south, as it gets full face of monsoon coming from the Bay of Bengal. To which its mountains form a barrier. At the end of September, after the last of the big rains, autumn suddenly arrives and sky gets clear, a brisk breeze picks up and temperature starts falling towards freezing at night although bright sunshine continues to keep the days warm. Autumn is the magnificent season that lasts until mid-November ("Geography of Bhutan," 2012).

5

Biodiversity of Bhutan

Importance of Biodiversity

Biological diversity plays a paramount role in every sphere of human existence and provides us with a

vast range of products and services. These are pivotal services such as food, water, timber, fibre,

genetic resources, and medicines; regulating services such as regulation of climate and, water and soil

quality, and pollination; cultural services such as recreational, aesthetic, and spiritual benefits; and

supporting services such as soil formation and nutrient cycling (Carlson et al., 2010). Biodiversity

also plays a significant role in mitigating and adapting the impacts of climate change. Intact

ecosystems such as forests and peat lands sequester carbon in their vegetation and soil thus supporting

climate-regulating functions worldwide (Amend & Eibing, 2010).

Bhutan straddles two major biogeographic realms, the Indo-Malayan and Palearctic and is part of the

Eastern Himalayan region which contains parts of three global biodiversity hotspots, 60 ecoregions,

330 important bird areas, 53 important plant areas, and a large number of wetlands and 29 Ramsar

sites(ICIMOD, 2010). Bhutan is home to a diverse array of flora and fauna including 5603 species of

vascular plants, 400 lichens, 200 mammals and about 700 birds. In addition to the currently known

105 endemic plant species, Bhutan also hosts a number of globally threatened species including 27

mammals and 18 birds (Climate Summit for a Living Himalayas, 2011).

Table 1.Different forest types and Characteristic Flora and Fauna in Bhutan (some species are subject

to change).

Zones Altitude (m)

Precipitation Characteristic Flora Characteristic Fauna

Dry Alpine Scrub

4,000-4,600 No information

Ephedra gerardiana,

Meconopsis simplicifolia,

Chesneya nubigena,

Tanacetum gossypinum,

Saussurea gossypiphora,

Rheum nobile

Mammals: Marmots, Snow leopard, Blue sheep, Pika, red fox, musk deer Birds: Tibetan snow cock, Snow partridge, Grandala, Lammergeier Himalayan monal pheasant Himalayan griffon, Alpine accentor, Oriental skylark, Blood Pheasant

Juniper/Rhododendron scrub

3,700-4,200 No information

Juniperus recurva, J.

squamata, Rhododendron

lepidotum,

Morina,nepalensis,Thalictrum,

chelidonfi,Pedicularis

megalalantha.

Mammals: Wild dog, Barking deer, Serow, Musk deer, Takin. Birds: white browed rose finch, Snow pigeon, White browed bush robin Golden bush robin, Blood Pheasant Fire tailed Sunbird.

Fir forest 3,100-3,300 (-3,800)

130 cm or more

Tsuga dumosa,Larix

griffithiana,Gaultheria

fragrantissima, Panax

puseudo-ginseng, Daphne

bholua, Arundinaria

griffithiana

Mammals: Sambhar, Serow, Black Bear, Barking deer. Birds: Black throated tit, Black throated fulvetta, Green-tailed sunbird, Rustyflanked tree creeper, Lesser cuckoo.

Spruce Forest (2,500-) 2,700-3,100 (-3,200)

50-100 Picea brachytyla, Rosa

macrophylla,Taxus

baccata,Picea spinulosa Acer

cappadocicum,Larix

girffithiana,Hydrangea sp.

Mammals: Sambhar, Birds: Black throated tit, Rusty flanked tree creeper, and Black throated fulvetta.

Blue pine 2,100-3,00(- 3,100)

70-120 Pinus wallichiana, Berberis

asiatica, Cotoneaster

griffithii,Lyonia ovalifolia,

Mammals: Leopard, Sambhar, and Goral. Birds: Green backed tit,

6

Source: (Grierson & Long, 1999).

Rhododendron arboreum,

Ansaema consanguineum.

Yellow billed blue magpie, Grey backed shrike, Red billed cough, common kestrel, Collared blackbird, White throated laughing thrush.

Everygreen oak forest 1,800-2,000(- ;2,600)

200-300 Acer campbelli, Castanopsis

hystrix, C. tribuloides,

Elatostema hookerianum,

Quescus lamellose, Skimmia

arborescens

Mammals: Tiger, barking deer, sambhar, wild dog. Birds: Kaleej’s pheasant, leaf warbler, Grey winged black bird, Green backed tit, chestnut breasted, wood snipe.

Cool broad leaved forest

2,000-2,900 250-500 Acercampbelli, Betula

alnoides, Exbuclandia

populnea. Lindera

pulcherrima, Persea

clarkeana, Symplocos

dryophila

Mammals: leopard, black bear, barking deer, red panda. Birds: white throated laughing thrush, rufous necked hornbill, chestnut, rowned laughing thrush, snowy browed fly catcher, mountain hawk eagle, tawny owl, ward's trogon Pygmy wren babbler, great babbler.

Chir pine forest 900-1,800 (- 2,00)

100-130 Pinus roxburghii, Cycas

pectinata, Cymbopogon

flexousus, Euphorbia

royleana, Woodfordia

fructicosa, Grewia sapida,

Buddleja bhutanica,

Rhododendron arboreum,

Mammals: Goral, Yellow throated martin, Barking deer. Birds: Black bulbul, Mountain bulbul, Grey-tree pie, Rufous woodpecker, Red-vented bulbul, Bar-winged flycatcher shrike Saphire flycatcher, and Himalayan bulbul

Warm broad leaved fores

1,000-2,000(- 2,300)

230-400 Altingia excelsa, Bischofia

javanica, Castanopsis indica,

Engelhardia spicata,

Macaranga postulata, Schima

wallichii, Alnus nepalensis.

Michelia exelsa, Morus sp.,

Amoora rhortica,

Mammals: Red panda, Barking deer, Sambhar, Tiger, Capped langur, Serow, Leopard. Birds: Rufous necked hornbill, Palla's fish eagle, Common Iora, white breasted kingfisher, Oriental turtle dove, Leaf warbler, Hodgson's hawk cuckoo, and Chestnut breasted partridges.

Subtropical forest 200-1,000(-1,200)

250-500 Acrocarpua fraxinifolius

Ailanthus grandis, Bombax

ceiba, Duabanga grandiflora,

Shorea robusta,

Pteroapermum acerifolium,

Aquilaria agaloocha, Gmelia

arborea, Terminalia sp.,

Michelia champaca, Acacia

catechu, Chukrasia tabularis,

Toona ciliata, Lagestroemia

sp., Phoebe sp., Artocarpus

sp.

Mammals: Golden langur, Capped langur, Pygmy hog, Marbled cat, Asiatic golden cat, Fishing cat, Tiger, Elephant, Clouded leopard. Birds: Large billed crow, Blue whistling thrush, Pin-tailed green pigeon, Orange breasted green pigeon, Spotted dove, Great coucal, Rose-ringed parakeet, Asian emerald , cuckoo, Blue bearded bee-eater, Blue bearded barber, Large hawk cuckoo, Rufous-necked hornbill, Pallas's fish eagle.

7

Forestry in Bhutan

One of Bhutan's significant natural resources in the late twentieth century is its rich forests and natural

vegetation. Bhutan's location in the eastern Himalayas, with its subtropical plains and alpine terrain,

gives it more rainfall than its neighbours to the west, a factor greatly facilitating forest growth. The

forests contain numerous deciduous and evergreen species, ranging from tropical hardwoods to

predominantly oak and pine forests (Wangda & Oshawa, 2006).

The small population and the general absence of overdevelopment in Bhutan contribute to forest

preservation. Because of the terrain, the more accessible forests had been overcut whereas remote

forests remain largely in their natural state. A progressive government-sponsored forestry

conservation policy strives to balance revenue needs with ecological considerations, water

management, and soil preservation.

The Department of Forestry was established in 1952 to oversee conservation and exploitation of the

country's significant forestry resources. After an initial decade of development, forestry resource

exploitation increased with the start of the First Development Plan in 1961. Uncontrolled felling of

trees in the 1970s by private companies in logging areas and by rural populations along roads and in

main valleys stripped hillsides and caused serious erosion (BAP, 2009).

In 1971 the Forestry School was established at Kalikhola in southern Bhutan. It was moved to Taba in

the northern Thimphu Valley in 1977. The school provided basic instruction in forestry and forest

management and trained foresters and Forest Guards.

In 1981 some 3.3 million hectares, or between 70 and 74 percent of the land, were forested, but in

1991 foreign estimates indicated a shrinking forest of only 60 to 64 percent of the land. Even more

conservative estimates indicated that closer to 50 percent of Bhutan's territory still was forested in the

late 1980s, and about 15 percent of GDP was produced through the nation's important forest industry.

Recognizing the potential value of its forestry resource, Bhutan became increasingly conscientious

about forestry management in the 1970s. Starting in 1977, the World Wildlife Fund began supporting

Bhutan's forest management through organizing forest ranger training programs, supplying funds for

forest boundary demarcation, building guard posts, and constructing a patrol road for what was later

to be designated the Royal Manas National Park.

In the face of increasing denuded hillsides, private logging was banned, and strict standards for

public-sector logging operations were established in 1979. Farmers were warned against burning off

forests to clear land for tsheri4 cultivation, and forest guards were trained in increasing numbers to

help preserve the valuable resources. Surveying, demarcation, conservation, and management plans

for harvesting forest products were part of the Fifth Development Plan's focus on forestry

preservation. Wildlife sanctuaries also were developed. One of the immediate results of forestry sector

regulation, however, was a sharp decrease in revenues since the late 1970s. In 1991 the government,

with assistance from UNDP and the World Wildlife Fund, established a trust fund for environmental

conservation. Initially in the amount of US$20 million, the UNDP-administered fund was aimed at

producing up to US$1 million per year for training in forestry and ecology, surveying forests,

reviewing and implementing management plans for protected areas, and supporting government

environmental offices, public awareness programs, and integrated conservation and development

programs (BAP, 2009).

4 Tsheri means shifting cultivation in Bhutan.

8

Threats and challenges The country has 70.46 percent of the total area under forest cover (LCMP, 2010) and 51.32 percent,

secured as protected areas and biological corridors. These serve not only as rich reservoirs of

biodiversity but indirectly serve as long-term stores of carbon which mitigate the adverse impacts of

climate change. The protected areas system of Bhutan is regarded as one of the most comprehensive

in the world. It encompasses a continuum of representational samples of all major ecosystems found

in the country, ranging from the tropical/sub-tropical grasslands and forests in the southern foothills

through temperate forests in the central mountains and valleys to alpine meadows in the northern

mountains (NEC, 2009). As addressed in above lines, Bhutan has an extensive network of rivers due

to the high level of precipitation, numerous glaciers and glacial lakes and well preserved forests

resulting in upstream and downstream benefits such as water and other ecosystem services (BAP,

2009).

However, Bhutan at the crossroads of development and modernization faces many challenges towards

the loss of its pristine natural biodiversity. According to United Nations Food and Agriculture

Organization, between 1990 and 2010, Bhutan lost an average of 10,700 ha or 0.35% per year. In

total, between 1990 and 2010, Bhutan gained 7.1% of its forest cover or around 214,000 ha.

Bhutan's forests contain 336 million metric tons of carbon in living forest biomass (FAO, 2011).

As mentioned, Bhutan has 51.32 percent of its total area secured as protected areas and biological

corridors, depicting that biodiversity in Bhutan are being mostly conserved by the protected areas.

Protected areas of Bhutan have some 748 known species of amphibians, birds, mammals and reptiles

according to figures from the World Conservation Monitoring Centre. Of these, 1.1% is endemic,

meaning they exist in no other country, and 5.3% are threatened. Bhutan is home to at least 5468

species of vascular plants, of which 1.4% are endemic. 29.6% of Bhutan is protected under IUCN

categories I-V. However, the biodiversity are in the verge of decreasing in number.

In Bhutan, loss of biodiversity is caused

by several factors such as changes in

land use, over exploitation of natural

resources, destruction of natural

habitats, urbanization, human wildlife

conflict, forest fires, hydropower

development, industrial development

and one of the important factor includes

introduction of invasive alien species in

the country (Millennium Ecosystem

Assessment 2005). Accordingly, the

governmental organizations and non-

governmental organizations in the

country are working hard to alleviate

these factors.

However, the knowledge of invasive species and the effect of invasive species on biodiversity are new

to Bhutan due to which, currently a very few numbers of works are done to study the invasive species

and essential mitigation activities against it. Such a trend where people are less aware and have

limited knowledge, and again if detailed studies on invasive species are not carried out, consequently,

invasive species can bring greater harm to the biodiversity, the local communities and the country as a

whole.

Figure 3. Forest cleared for construction of road.

9

Invasive species

According to the National Invasive Species Council (NISC) and the Invasive Species Advisory

Committee (ISAC), the United states (2006), invasive species is defined as, “a species that is non-

native to the ecosystem under consideration and whose introduction causes or is likely to cause

economic or environmental harm or harm to human health”.

Today, all the nations around the globe are focusing on invasive species which are known to cause or

likely to cause negative impacts and that do not provide an equivalent or greater benefit to society. In

the technical sense, the term ‘invasion’ simply denotes the uncontrolled or unintended spread of an

organism outside its native range with no specific reference about the environmental or economic

consequences of such spread or their relationships to possible societal benefits.

For a non-native organism to be considered an invasive species, the negative effects that the organism

causes or is likely to cause are deemed to outweigh any beneficial effects. Many non-native

introductions provide benefits to society and even among species that technically meet the definition

of invasive, societal benefits may greatly exceed any negative effects (for example crops and livestock

raised for food). However, in some cases any positive effects are clearly overshadowed by negative

effects, and this is the concept of invasive species, causing harm (NISC, 2006).

The negative impact to a native species caused by an invasive species might trigger additional

negative interactions for other associated native species; that is, there could be direct and indirect

effects. For example, an invasive weed that is undesirable as a food source may outcompete and

displace native grasses and broadleaf plants. These displaced native grasses and broadleaf plants may

have been primary forage for animals, which subsequently would be displaced to a new location or

have their populations reduced because the weed invasion decreased the availability of food in their

native plant and animal community. However, negative effects are not always characterized by a

cascade of impacts realized throughout the environment. For example, simple displacement of an

endangered species by a non-native species might alone provide sufficient justification to consider the

non-native organism an invasive (NISC, 2006).

Phase of biological invasion in Bhutan Biological invasion depends on chances or routes of invasion on the one hand, and the presence or

abundance of habitats where the introduced species can establish themselves on the other. Active

foreign trade inevitably facilitates both intentional and unintentional introductions. On the other hand,

human reformation of habitat conditions through development of roads, farmlands, plantations and

cities prepares new habitats with ample void niches no native species have pre-empted (Washitani,

2004).

An era demarcating the beginning of alien species invasions into Bhutan was the rapid economic

growth period which started in the 1960s5 when the landscapes of Bhutan began to change greatly due

to various types of development works according to a national plan to bring about the development.

After that era, invasions have become more frequent than ever. The globalization of trade and

enhanced habitat alterations can be considered the major reasons for accelerated invasions.

5 During this period Bhutan underwent an enormous development especially the closure of Tibetan borders and opening roads and links to India.

10

Two of the major families contributing to the invasive alien herbaceous flora of Bhutan are the

Compositae and Graminae. The Compositae is being well characterized by highly dispersible

aerochorous seeds and/or long-lived seeds that tend to be persistent in soil seed banks. Contemporary

surface soils of various habitats of Bhutan, including wetlands, woodlands, plantations, floodplains

and farmlands have more or less accumulated viable seeds of such alien plant species, even if the

above-ground vegetation contains no or few alien plant species.

List of known invasive species in Bhutan till date are listed in the following subheading, according to

Global Invasive species Database6 (2012) and Invasive species compendium (2012), currently there

are about 200 invasive species found in the country irrespective of both plants and animals in all

ecological habitats. Studies are still under process to update and find out the actual number of invasive

species found in the country. However, the following listed invasive species accounts for only plant

invasive species found in the country, which are listed as follows:

Invasive species found in Bhutan and their common names 1. Acacia melanoxylon (tree)

Common Names: acacia rouge, Australian blackwood, blackwood, blackwood acacia,

Tasmanian blackwood.

2. Cardamine flexuosa (herb)

Common Names: wavy bittercress, wavy-leaved bittercress, wood bittercress

3. Chromolaena odorata (herb)

Common Names: agonoi, bitter bush, chromolaena, hagonoy, jack in the bush, Siam weed,

Siam-Kraut, triffid weed.

4. Anagallis arvensis

Common name: scarlet pimpernel

5. Arceuthobium minutissimum

Common name: Himalayan dwarf mistletoe

6. Argemone mexicana

Common name: Mexican poppy

7. Arundo donax

Common name: giant reed

8. Avena fatua

Common name: wild oat

6 The Global Invasive Species Database is managed by the Invasive Species Specialist Group (ISSG) of the IUCN Species

Survival Commission. It was developed as part of the global initiative on invasive species led by the Global Invasive Species

Programme (GISP) and is supported through partnerships with the National Biological Information Infrastructure, Manaaki

Whenua-Landcare Research and the University of Auckland.

11

9. Imperata cylindrica (grass)

Common Names: cogon grass, satintail, speargrass.

10. Borreria latifolia

Common name: broadleaf button weed

11. Brachypodium sylvaticum

Common name: slender false brome

12. Bryophyllum pinnatum

Common name: air plant

13. Calotropis procera

Common name: apple of sodom

14. Albizia julibrissin (tree)

Common Names: mimosa, powderpuff tree, silk tree, silky acacia

15. Alternanthera sessilis (herb)

Common Names: common roadside weed, dwarf copperleaf

16. Chenopodium album

Common name: fat hen

17. Commelina diffusa

Common name: spreading dayflower

18. Bacopa monnieri (herb)

Common Names: coastal water hyssop, gundala, herb of grace, Indian pennywort

19. Caesalpinia decapetala (tree, shrub)

Common Names: cat's claw, Mauritius thorn, Mysore thorn, shoofly, wait-a-bit

20. Commelina benghalensis (herb)

Common Names: Benghal dayflower, bias-bias, blue commelina, dayflower hairy

21. Convolvulus arvensis

Common name: bindweed

22. Dalbergia sissoo (tree)

Common Names: Bombay blackwood, dalbergia, Himalaya raintree, shisham, sisso

12

23. Dioscorea bulbifera (herb, vine, climber)

Common Names: ‘oi, aerial yam, air yam, air-potato, bitter yam, cheeky yam, rook, wild

yam, yam

24. Ficus microcarpus (tree)

Common Names: Chinese banyan, curtain fig, laurel fig, Malay banyan, rong shu

25. Conyza bonariensis

Common name: hairy fleabane

26. Conyza canadensis

Common name: Canadian fleabane

27. Houttuynia cordata (shrub)

Common Names: chameleon-plant

28. Hygrophila polysperma (aquatic plant)

Common Names: East Indian hygrophila, Indian swamp weed, Miramar weed

29. Lespedeza cuneata (herb, shrub)

Common Names: Chinese bush-clover, Chinese lespedeza, hairy lespedeza, Himalayan

bushclover, perennial lespedeza, silky bush-clover

30. Limnophila sessiliflora (herb)

Common Names: ambulia, Asian marshweed, limnophila,

31. Lotus corniculatus (herb)

Common Names: birdfoot deervetch, bird's-foot trefoil, cat's clover, common lotus

32. Lygodium japonicum (vine, climber, fern)

Common Names: Japanese climbing fern

33. Conyza sumatrensis

Common name: tall fleabane

34. Melilotus alba (herb)

Common Names: honey clover, honey-lotus, hubam clover, melilot, Melilotos, tree clover,

white melilot, white millet, white sweet clover

35. Neyraudia reynaudiana (grass)

Common Names: burma reed, cane grass, false reed, silk reed

13

36. Paederia foetida (vine, climber)

Common Names: Chinese fever vine, skunk vine , stink vine

37. Crassocephalum crepidioides

38. Cuscuta campestris

Common name: field dodder

39. Cuscuta europaea

Common name: European dodder

40. Rubus niveus (shrub)

Common Names: Ceylon raspberry, hill raspberry, Java bramble, Mahabaleshwar raspberry,

Mysore raspberry, snowpeaks raspberry

41. Cuscuta reflexa

Common name: dodder

42. Senegalia catechu (tree)

Common Names: black catechu, black cutch, catechu, cutchtree, khair, khairtree

43. Cynodon dactylon

Common name: Bermuda grass

44. Cyperus compressus

Common name: annual sedge

45. Verbascum thapsus (herb)

Common Names: Aaron's-rod, big taper , common mullein , flannel mullein , flannel plant ,

hag taper , mullein , torches , velvet dock , velvet plant , woolly mullein

46. Marsilea minuta

Common name: pepperwort

47. Cyperus iria

Common name: rice flatsedge

48. Pteridium aquilinum

Common name: bracken

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49. Acacia farnesiana

Common name: huisache

50. Acanthospermum hispidum

Common: bristly starbur

51. Achyranthes aspera

Common name: devil's horsewhip

52. Ageratina adenophora

Common name: Crofton weed

53. Ageratum conyzoides

Common name: billy goat weed

54. Albizia lebbeck

Common name: Indian siris

55. Amaranthus hybridus

Common name: smooth pigweed

56. Amaranthus spinosus

Common name: spiny amaranth

57. Cyperus rotundus

Common name: purple nutsedge

58. Datura stramonium

Common name: jimsonweed

59. Delonix regia

Common name: flamboyant

60. Digitaria ciliaris

Common name: southern crabgrass

61. Digitaria longiflora

Common name: false couch grass

15

62. Echinochloa colona

Common name: junglerice

63. Echinochloa crus-galli

Common name: barnyard grass

64. Eclipta prostrata

Common name: eclipta

65. Eichhornia crassipes

Common name: water hyacinth

66. Elaeagnus umbellata

Common name: autumn olive

67. Eleusine indica

Common name goose grass)

68. Euphorbia heterophylla

Common name: wild poinsettia

69. Euphorbia hirta

Common name: garden spurge

70. Galinsoga parviflora

Common name: gallant soldier

71. Gliricidia sepium

Common name: mother of cocoa

72. Hedychium gardnerianum

Common name: kahili ginger

73. Jatropha curcas

Common name: physic nut

74. Lemna perpusilla

Common name: duckweed

16

75. Leucaena diversifolia

76. Leucaena leucocephala

Common name: leucaena

77. Ludwigia hyssopifolia

Common name: water primrose

78. Melia azedarach

Common name: Chinaberr

79. Melinis minutiflora

Common name: molasses grass

80. Mikania micrantha

Common name: mile-a-minute

81. Mimosa pudica

Common name:sensitive plant

82. Monochoria vaginalis

Common name: pickerel weed

83. Murdannia nudiflora

Common name: doveweed

84. Myriophyllum spicatum

Common name: spiked watermilfoil

85. Oxalis latifolia

Common name: sorrel

86. Parthenium hysterophorus

Common name: parthenium weed

87. Paspalum conjugatum

Common name: sour paspalum

17

88. Paspalum distichum

Common name: knotgrass

89. Paspalum scrobiculatum

Common name: rice grass paspalum

90. Pennisetum clandestinum

Common name: kikuyu grass

91. Pennisetum pedicellatum

Common name: deenanath grass

92. Phalaris minor

Common name: Little seed canarygrass

93. Phyllanthus urinaria

Common name: leaf flower

94. Pithecellobium dulce

Common name: Manila tamarind

95. Plantago lanceolata

Common name: ribwort plantain

96. Poa annua

Common name: annual meadow grass

97. Polygonum aviculare

Common name: prostrate knotweed

98. Polygonum barbatum

Common name: knot grass

99. Polygonum hydropiper

Common name: marsh pepper

100. Polygonum nepalense

Common name: Nepal persicaria

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101. Polygonum persicaria

Common name: redshank

102. Pueraria montana var. lobata

Common name: kudzu

103. Robinia pseudoacacia

Common name: black locust

104. Rubus ellipticus

Common name: yellow Himalayan raspberry

105. Samanea saman

Common name: rain tree

106. Senna obtusifolia

Common name: sicklepod

107. Senna occidentalis

Common name: coffee senna

108. Solanum viarum

Common name: tropical soda apple

109. Spergula arvensis

Common name: corn spurry

110. Stellaria media

Common name: common chickweed

111. Striga asiatica

Common name: witch weed

112. Syzygium cumini

Common name: black plum

113. Thlaspi arvense

Common name: field pennycress

19

114. Urochloa panicoides

Common name: liverseed grass

115. Xanthium strumarium

Common name: common cocklebur

The above listed invasive species accounts for species belonging to kingdom Plantae found in Bhutan.

However, the following subtopics will address plant invasive species particularly belonging to

kingdom Plantae found in different ecological habitats of protected areas in the country. Bhutan has

about 51.32% of total areas designated as protected areas, which encompasses national parks,

sanctuaries, nature reserves and biological corridors.

Most of the forests are under the protected areas, and one of the unique characteristics about the

protected areas of Bhutan is the human inhabitants inside the protected areas. People have been

sustaining their livelihoods simply depending on forest and natural resources from times immemorial.

The establishment of protected areas few decades ago aims to protect the forest as well as the

sustainably manage without any bane on the local inhabitants, which has been challenging.

The local inhabitants have been cooperating with the concerned authorities and organizations in

protecting and sustainable use of natural resources in the protected areas. However, it is again the

people who play the part in destroying forest; causing factors like forest fire, illegal cutting down of

trees for timbers, illegal poaching and one way or another introducing non native plant and animal

species, which is now seriously causing havocs in the forests and the lives of people too, for instance,

weeds in agricultural fields.

Protected Areas in Bhutan

Protected areas are special areas with rich natural and associated cultural diversity especially

protected to conserve some of the most significant and important biological diversity in the country

(Goriup, 1999).

The protected areas system of Bhutan was initiated in the 1960’s, and then covered almost the entire

southern and northern regions of the country. In 1993, as a financing condition for the Bhutan Trust

Fund, the parks system was revised for better ecological representation and realistic management.

Bhutan today has 10 formally protected areas covering 16,396.43 square kilometers, which is more

than a quarter of total area of the country (Sherpa & Norbu, 1993).

In Bhutan, the protected areas network covers some of the important and critical ecosystems in the

country stretching from sub-tropical to mid temperate to alpine zones. Protected areas of Bhutan is

home to a diverse array of flora and fauna including 5603 species of vascular plants, 400 lichens, 200

mammals and about 700 birds. In addition to the currently known 105 endemic plant species, Bhutan

also hosts a number of globally threatened species including 27 mammals and 18 birds.

20

There are nine protected areas in the country covering 17 dzongkhags and consists of four national

parks, four wildlife sanctuaries and one strict nature reserve.

Figure 4. Protected areas of Bhutan (source: Bhutan Trust Fund Bhutan Trust Fund for Environmental Conservation, 2012).

Out of these nine protected areas, currently only six are operational. They are Jigme Dorji National

Park, Jigme Singye Wangchuck National Park, Royal Manas National Park, Thrumshingla National

Park, Bomdeling Wildlife Sanctuary and Sakteng Wildlife Sanctuary. The remaining three areas

of Phibsoo Wildlife Sanctuary, Khaling Wildlife Sanctuary and Toorsa Strict Nature Reserve are yet

to be operational. The parks of Bhutan are described briefly below, focusing on key features and their

underlying importance to our natural heritage and conservation efforts.

Invasive species in Protected areas As addressed above that the role played by the protected areas in Bhutan are of paramount importance

to the conservation of Biodiversity and the livelihood of local communities. Knowing the pivotal roles

played by the protected areas in Bhutan, the Department of forest and park services, under the

Ministry of Agriculture and Forest brings its best service towards protecting these areas. Out of many

factors that cause the degradation of Biodiversity and bring bane in livelihoods of countrymen is the

non native invasive species, which has lead to the vitality and productivity of native species.

Lately, people have felt the importance of their focus on invasive species if they are protect the native

species of plants and animals. Invasive plant species have caused havocs from times immemorial.

Today, one of the major growing concerns of conservationists in Bhutan is about knowing invasive

species present in the country and implementing successful strategies to mitigate or eradicate the

invasive species and their effects. National parks and sanctuaries and their different ecological

habitats are the places where studies are best suited to be carried out, because most of the forests are

under protected areas in Bhutan.

21

Common invasive species in different ecological habitats of Protected areas

Out of about 200 invasive species found in the country, some invasive species are commonly found

and focus of studies on these species is of paramount importance. Common invasive species found in

the protected areas irrespective of all ecological habitats are listed as follows:

1. Acacia melanoxylon (tree)

Acacia melanoxylon is native in eastern Australia. This tree

grows fast and tall, up to 45m height. It has a wide ecological

tolerance, occurring over an extensive range of soils and

climatic conditions, but develops better in colder climates.

Control of its invasion of natural vegetation, commercial

timber plantations and farmland incurs considerable costs, but

its timber value and nursing of natural forest succession

provides a positive contribution.

Common Names: acacia rouge, Australian blackwood,

blackwood, blackwood acacia.

Synonyms: Racosperma melanoxylon (R.Br.) C.Martius

2. Cardamine flexuosa (herb)

Woodland bittercress, Cardamine flexuosa is a highly variable

perrenial herb which flowers vigourously and forms dense root

mats that can exclude other species. Seeds possibly remain viable

in the seed bank for up to seven years requiring intensive

management for control/eradication.

Common Names: wavy bittercress, wavy-leaved bittercress,

wood bittercress, woodland bittercress

Synonyms: Cardamine hirsuta ssp. flexuosa (With.)

Figure 5. Acacia melanoxylon, morphology

Figure 6. Morphology of Cardamine

flexuosa.

22

3. Chromolaena odorata (herb)

Chromolaena odorata is a fast-growing perennial shrub,

native to South America and Central America. It has been

introduced into the tropical regions of Asia, Africa and the

Pacific, where it is an invasive weed. Also known as Siam

weed, it forms dense stands that prevent the establishment

of other plant species. It is an aggressive competitor and

may have allelopathic effects. It is also a nuisance weed in

agricultural land and commercial plantations.

Common Names: agonoi, bitter bush, chromolaena,

hagonoy, jack in the bush, Siam weed, Siam-Kraut, triffid

weed.

Synonyms: Eupatorium affine Hook & Arn., Eupatorium

brachiatum Wikstrom, Eupatorium clematitis

4. Imperata cylindrica (grass)

Native to Asia, cogon grass (Imperata cylindrica) is

common in the humid tropics and has spread to the warmer

temperate zones worldwide. Cogon grass is considered to

be one of the top ten worst weeds in the world. Its extensive

rhizome system, adaptation to poor soils, drought tolerance,

genetic plasticity and fire adaptability make it a formidable

invasive grass. Increases in cogon grass concern ecologists

and conservationists because of the fact that this species

displaces native plant and animal species and alters fire

regimes.

Common Names: cogon grass, satintail,

speargrass.Synonyms: Imperata arundinacea, Lagurus

cylindricus L.

5. Albizia julibrissin (tree)

Albizia julibrissin is commonly used as an ornamental tree

because of its appealing fragrance, showy flowers and low

maintenance requirement. It has escaped from the urban

landscape and competes with native plants in disturbed habitats

and occasionally in forested areas. Typical disturbed habitat

may include roadsides, vacant lots and riparian areas. Albizia

julibrissin prefers full sunlight but is salt and drought tolerant

and can thrive in a wide range of soil types.

Common Names: mimosa, powderpuff tree

Figure 7. Chromolaena odorata

Figure 8. Imperata cylindrica

Figure 9. Albizia julibrissin

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6. Alternanthera sessilis (herb)

Alternanthera sessilis is a weed that inhabits many

areas of the world. It occupies moist areas and can be

found from sea level to over 2000m. Alternanthera

sessilis is a pest of sugarcane, a weed of rice in tropical

areas, and an agricultural weed that invades disturbed

wet areas in tropical and subtropical regions. It has been

used widely around the world for its medicinal uses, as

well as for food. The plant has been readily used for

food partly due to its abundance.

Common Names: common roadside weed, dwarf

copperleaf

Synonyms: Achyranthes linearifolia,

7. Verbascum thapsus (herb)

Verbascum thapsus is an erect herb in the family

Scrophulariaceae. It is found in neglected meadows and

pasture lands, along fencerows and roadsides. It can

produce 100,000-180,000 seeds per individual plant and

seeds may remain viable for over 100 years. Verbascum

thapsus threatens natural meadows and forest openings,

where it adapts easily to a wide variety of site conditions

and an established population can be extremely difficult

to eradicate. Verbascum thapsus was once used as a

herbal remedy for bronchitis, colds and congestion.

Common Names: Aaron's-rod, big taper , common

mullein , flannel mullein , flannel plant , hag taper,

mullein , torches21.

8. Commelina benghalensis (herb)

Believed to be native only to tropical Asia and

Africa, Commelina benghalensis is a widely distributed

herbaceous weed that commonly invades agricultural sites

and disturbed areas. Though not commonly reported to

invade natural areas, this rapidly reproducing plant is

considered one of the most troublesome weeds for 25

crops in 29 different countries.

Common Names: : Benghal dayflower, bias-bias, blue

commelina, dayflower hairy honohono

Synonyms: Commelina canescens Vahl

Figure 10. Alternanthera sessilis

Figure 11. Verbascum thapsus

Figure 12. Commelina benghalensis

24

9. Bacopa monnieri (herb)

Bacopa monnieri is a small sprawling herb

common in fresh and brackish waters. It is found

growing in freshwater wetlands, wet pastures and

margins of ponds on Grand Cayman where it is

listed as an invasive species.

Common Names: coastal water hyssop, gundala,

herb of grace, Indian pennywort

Synonyms: Bramia monnieri (L.)

10. Caesalpinia decapetala (tree, shrub)

Mysore thorn (Caesalpinia decapetala ) originates from tropical

and eastern Asia but is now a serious weed in many locations such

as South Africa, Tanzania, Zimbabwe, Hawaii, Portugal, New

Zealand and Norfolk Island. It has become a major invasive plant

in South Africa and Hawaii, where it has the capability to take over

large areas of agricultural land, limiting animal movement. This

sprawling, thorny and noxious shrub also invades forest margins,

smothering native vege tation.

Common Names: cat's claw, Mauritius thorn, Mysore thorn,

shoofly, wait-a-bit

Synonyms: Biancaea decapetala (Roth)

Figure 13. Bacopa monnieri

Figure 14. Caesalpinia decapetala pods

Figure 15.Caesalpinia decapetala

25

11. Dioscorea bulbifera (herb, vine, climber)

Dioscorea bulbifera is a highly invasive plant and

presents a management problem in many parts of the

world. Despite some medicinal and agricultural

uses, D. bulbifera is widely characterized as an

organism that outcompetes and smothers native

vegetation.

Common Names: aerial yam, air yam, air-potato,

bitter yam, cheeky yam, rook, wild yam, yam

Synonyms: Dioscorea hoffa

12. Ficus microcarpus (tree)

Ficus microcarpa is a woody plant species that is

native to the Asia-Pacific region. Commonly known

as Chinese banyan and the laurel fig, it is a popular

ornamental tree that grows in tropical and temperate

regions of the world. F. microcarpa has small, tiny

seeds that are easily spread by birds, bats and

rodents, and which are capable of germinating almost

anywhere they land - even in cracks in concrete. F.

microcarpa is considered to be a major invasive

species in Hawaii, the Bonin (Ogasawara) Islands,

Florida, Bermuda and Central down to South

America.

Common Names: Chinese banyan, curtain fig, laurel

fig, Malay banyan, rong shu

Synonyms: Ficus microcarpa

13. Dalbergia sissoo (tree)

Dalbergia sissoo is a perennial tree that is economically important for its value in forestry,

agroforestry, and horticulture. It provides timber, fuel wood, fodder, has medicinal value, used

extensively as an ornamental tree as well as for shading, erosion control, and soil fertility. Native to

the Indian sub-continent it is a member of the legume family and can fix nitrogen from the

atmosphere through bacteria nodules on its root system. It has been introduced in various countries

throughout the world, but has known to be invasive in Australia and in Florida (Congress).

Common Names: Bombay blackwood, dalbergia, Indian dalbergia, shisham, sisso

Synonyms: Amerimnon sissoo (Kuntze), Dalbergia pseudo-sissoo (Miq.)

Figure 16. Dioscorea bulbifera

Figure 17. Ficus microcarpus

26

14. Houttuynia cordata (shrub)

Houttuynia cordata is a perennial plant that has been

introduced as an ornamental for gardens. While the plant

has apparently not escaped confinement, there is much

fear that it will eventually present a huge risk to native

habitats. It has a high reproductive and vegetative

growth rate and quickly overtakes the gardens where it

is planted. Control of this species is difficult as it will

reproduce rhizomatically from fragments.

Common Name: chameleon-plant

Synonyms: Gymnotheca chinensis,

15. Hygrophila polysperma (aquatic plant)

The herbaceous perennial Hygrophila polysperma, commonly known as the Indian swamp weed, is a

freshwater amphibious herb that was most likely introduced through the aquarium trade. It is found in

warmer climates and prefers flowing streams, but may also

be found in slow-moving waters and in lakes. It is a fast-

growing and fast-spreading species that out-shades and out-

competes other submersed plants. Hygrophila polysperma

interferes with navigation and has been known to compete

with other aggressive non-native invasive plants.

Hygrophila polysperma is difficult to control. Mechanical

harvesting only fragments the plants and increases its

distribution. Typical biological control agents for aquatic

invasive species do not affect this species and most

registered aquatic herbicides only provide marginal control.

Common Names: East Indian hygrophila, hygro, Indian

swamp weed, Miramar weed

Synonyms: Hemidelphis polysperma (Roxb.)

16. Lespedeza cuneata (herb, shrub)

Lespedeza cuneata is a long-lived perennial that grows well in grasslands, pastures, along roadsides,

drainage areas, fence rows and in other disturbed areas. It is often found as a weed in cultivated areas,

fallow and abandoned fields, meadows and marshes. It is adapted to a wide range of climatic

conditions and is tolerant of drought. Lespedeza cuneata can survive freezing winter temperatures, but

is often damaged by late spring freezes. Lespedeza cuneata grows best in deep soils, such as deep

sands with organic matter or sandy loams with clay loam subsoil. It will also grow on strongly acidic

to neutral soils. Dispersal is aided by animals that consume the fruits then pass the seeds; autumn

dispersal is aided by the collection of hay in infested fields.

Common Names: Chinese bush-clover, Chinese lespedeza, Himalayan bush clover

Synonyms: Anthyllis cuneata, Aspalathus cuneata

Figure 18. Houttuynia cordata

Figure 19. Hygrophila polysperma

27

17. Limnophila sessiliflora (herb)

Limnophila sessiliflora is an aquatic perennial herb

that can exist in a variety of aquatic habitats. It is

fast growing and exhibits re-growth from

fragments. Limnophila sessiliflora is also able to

shade out and out compete other submersed

species. 2-4, D reportedly kills this species.

Common Names: ambulia, Asian marshweed,

limnophila, shi long wei

Synonyms: Hottonia sessiliflora


Lotus corniculatus (bird's foot trefoil) is a low

growing perennial legume that has long been valued

as an agricultural crop. Lotus corniculatus is native

to much of Europe, Asia and parts of Africa, but

now has a near global distribution. Over most of its

range, Lotus corniculatus is not considered

invasive, although in a few areas it has out-

competed native vegetation.

Common Names: birdfoot deervetch, bird's-foot

trefoil, cat's clover, common lotus, devil's fingers,

Synonyms: Lotus ambiguous, Lotus ambiguus,

Lotus japonicus

19. Lygodium japonicum (vine, climber, fern)

Lygodium japonicum is a vine-like fern with a

highly developed ability to climb herbs, shrubs and

trees. Its invasiveness arises from its ability to

climb to heights of 30m and can smother vegetation

by forming dense mats which displace native

species, alters fire ecology and impacts rare,

threatened and endangered species.

Common Names: Japanese climbing fern

Synonyms: Hydroglossum japonicum

Figure 20. Limnophila sessiliflora

Figure 22. Lotus corniculatus

Figure 23. Lygodium japonicum

Figure 21. Lotus corniculatus

28

20. Paederia foetida (vine, climber)

Paederia foetida is an aggressive, competitive vine. It can grow high into the canopy of trees in a

variety of habitats. The vines climb over

shrubs and trees, weighing them down and

impeding regeneration. It also invades

pastureland and is troublesome along roads

and on power lines. Chemicals are often

used as an effective method of controlling

Paederia foetida. The seeds may be

dispersed by birds and are also spread by

the transport of rooted fragments.

Common Names: Chinese fever vine

Synonyms: Paederia chinensis

21. Melilotus alba (herb)

Native to Asia, Europe, and northern Africa,

Melilotus alba (commonly known as white

sweet clover) was introduced to the United States and first recorded in 1739.

Common Names: honey clover, honey-lotus, tree clover, white melilot, white millet

Synonyms: Melilotus alba, Melilotus alba L., Melilotus albus

22. Neyraudia reynaudiana (grass)

Neyraudia reynaudiana presents a threat to ecosystems

due to its ability to promote frequent fires and

outcompete with native vegetation. Neyraudia

reynaudiana thrives from sea level to altitudes of 1980

metres. It is remarkably tolerant with respect to edaphic

and light regimes, although it seems to prefer open, high

light areas. Most invasions of Neyraudia reynaudiana

have been preceded by some form of disturbance. It has

often been collected in marshy areas, or areas with

brackish water, and is becoming increasingly common

in dry pinelands. It spreads via rhizomes and reproduces

by seeds, which are dispersed by wind.

Common Names: Burma reed, cane grass, false reed,

Synonyms: Arundo reynaudiana Kunth.

Figure 24. Neyraudia reynaudiana

Figure 25. Paederia foetida, skunk vine showing its leaves and

flowers

29

23. Senegalia catechu (tree)

Common Names: black catechu, black

cutch, catechu, cutch tree, khair, khairtree

Synonyms: Acacia catechu


Rubus niveus is a shrub native to Asia that

may form dense, impenetrable, thorny

thickets that can displace native species. It

produces sweet; palatable fruit enjoyed by

birds, rodents, reptiles and humans and has

been cultivated in many regions throughout

the world for this reason. It is also used as a

living fence. Mechanical management of

the species is difficult due to its growth

form and persistent seed bank, but chemical

methods have been developed and

biological means of management are being

explored.

Common Names: Ceylon raspberry, hill

raspberry, Java bramble, Mysore raspberry,

snow peaks raspberry

Synonyms: Rubus pedunculosus, Rubus

albescens

Figure 26. Senegalia catechu

Figure 27. Hill raspberry

30

Common invasive species in ecological habitats of National parks

Jigme Dorji National Park

Sprawling across 4,349 sq km, Jigme Dorji National Park is Bhutan's largest sanctuary. The park was

named after the third King of Bhutan, His majesty King Jigme Dorji Wangchuck who is often referred

to as the Father of Modern Bhutan. The national park covers the entire district of Gasa and the

western areas of Thimphu and Paro districts (Figure 4. Protected areas of Bhutan (source: Bhutan

Trust Fund Bhutan Trust Fund for Environmental Conservation, 2012).). Goral, the primitive and rare

mountain goat, is unique to it though. Gorals are solitary in nature and are monomorphic (males and

females look alike). On the southern boundary of Jigme Dorji National Park, Cheri Monastery 7is

situated at an altitude of 2600 m above sea level on a steep mountain slope (Bhutan Trust Fund

Bhutan Trust Fund for Environmental Conservation, 2012).

On one side of the monastery, there are broad-leaved forests boasting of oak, rhododendron, maple

and walnut trees and on the other side, there are conifer forests having spruce trees, fir, hemlock and

the Himalayan yew. The River Thimphu Chhu that originates in the Jigme Dorji National Park is quite

furious in summer, when it is fed by the melting snow, and its white torrential waters form emerald-

green pools throughout the park. The blood-red flowers of rhododendron and other blooming flowers

around the monastery present a colourful view in the spring season ("Jigme Dorji National Park,"

2012).

Several bird species are spotted in the park such as rare black-necked cranes, white-capped water

redstarts, blue whistling thrushes, white-throated laughing thrushes, yellow-billed blue magpies,

Himalayan monal and the spotted nutcracker. Cheri goral can easily climb the rock-face, which

provides them the escape point from predators such as tigers, leopards and dogs. The altitudes vary

widely throughout the park, from 1400 m to 7000 m, covering eight of the eleven vegetation zones

found in Bhutan. Jigme Dorji National Park has more than 30 species of mammals, 300 species of

birds, and 1400 species of plants. Black bears, markot, sambar, barking deer, takin and musk deer are

also found in this preserved area. Semi-nomadic people living here are mostly yak herders; harvests

medicinal and aromatic plants and subsist on marginal agriculture and forest products (Bhutan Trust

Fund Bhutan Trust Fund for Environmental Conservation, 2012).

It is the country’s most active geothermic region and Himalayan herbs found here are used in

traditional Bhutanese medicines. Trekkers love this place and the hot springs of the park, known as

Gasa Tsachhu, are famous for their therapeutic effects. One of the most biologically rich areas in the

Eastern Himalayan region, Jigme Dorji National Park boasts of warm broad-leaved forests, permanent

ice fields and even glaciers. Sacred peaks such as Jomolhari, Tsherimgang and Jichu Drakey are some

of the most significant landmarks in the park and its glaciers and glacial lakes are source of some of

the Bhutan’s main rivers. In the alpine region, one can see the rare blue poppy, edelweiss, orchids and

rhododendrons and it is perhaps the only place in the world where one can find snow leopards and the

Royal Bengal tiger existing together ("Jigme Dorji National Park," 2012).

7 It has the distinction of being the seat of the first monastic body in Bhutan. Zhabdrung Ngawang Namgyal, a Tibetan holy man, built it in 1620.

31

However, the rich biodiversity of the park constantly faces many threats, of which one of threat is

rapidly spreading invasive species. The common invasive species found in Jigme Dorji National Park

are as follows:

A. Invasive species in natural forests:

1. Acacia melanoxylon (tree), 2. Chromolaena odorata (herb), 3. Imperata cylindrica (grass),

4. Hemidactylus frenatus (reptile), 5. Caesalpinia decapetala (tree, shrub), 6. Houttuynia

cordata (shrub), 7. Lespedeza cuneata (herb, shrub), 8. Lygodium japonicum (vine, climber, fern),

9. Macaca mulatta (mammal), 10. Melilotus alba (herb), 11. Neyraudia reynaudiana (grass),

12. Paederia foetida (vine, climber) , 13. Pycnonotus jocosus (bird) , 14. Rubus niveus (shrub),

15. Suncus murinus (mammal), 16. Viverricula indica (mammal), 17. Corvus splendens (bird)

B. Invasive species in marine habitats:

1. Salmo trutta (fish), 2. Vibrio cholerae (micro-organism)

C. Invasive species in estuarine habitats:

1. Alternanthera sessilis (herb), 2. Cyprinus carpio (fish), 3. Salmo trutta (fish), 4. Vibrio

cholerae (micro-organism), 5. Lygodium japonicum (vine, climber, fern)

D. Invasive species in lakes:

1. Ctenopharyngodon idella (fish), 2. Cyprinus carpio (fish), 3. Hypophthalmichthys molitrix (fish),

4. Hypophthalmichthys nobilis (fish), 5. Salmo trutta (fish), 6. Hygrophila polysperma (aquatic plant)

E. Invasive species in wetlands:

1. Acacia melanoxylon (tree), 2. Cardamine flexuosa (herb),3. Cyprinus carpio (fish), 4. Imperata

cylindrica (grass), 5. Vibrio cholerae (micro-organism), 6. Alternanthera sessilis (herb), 7. Lespedeza

cuneata (herb, shrub), 8. Limnophila sessiliflora (herb), 9. Lygodium japonicum (vine, climber, fern)

10. Neyraudia reynaudiana (grass), 11. Paederia foetida (vine, climber)

F. Invasive species in riparian zones:

1. Acacia melanoxylon (tree) 2. Cardamine flexuosa (herb) 3. Chromolaena odorata (herb)

4. Imperata cylindrica (grass), 5. Albizia julibrissin (tree), 6. Alternanthera sessilis (herb), 7. Anas

platyrhynchos (bird), 8. Caesalpinia decapetala (tree, shrub), 9. Corvus splendens (bird),

10. Lygodium japonicum (vine, climber, fern), 11. Porphyrio porphyrio (bird), 12. Rubus

niveus (shrub), 13. Streptopelia decaocto (bird), 14. Viverricula indica (mammal)

G. Invasive species in ruderal/disturbed:

1. Acacia melanoxylon (tree), 2. Chromolaena odorata (herb), 3. Columba livia (bird), 4. Imperata

cylindrica (grass), 5. Hemidactylus frenatus (reptile), 6. Albizia julibrissin (tree), 7. Alternanthera

sessilis (herb), 8. Caesalpinia decapetala (tree, shrub), 9. Commelina benghalensis (herb), 10. Corvus

splendens (bird), 11. Lygodium japonicum (vine, climber, fern), 12. Macaca mulatta (mammal),

13. Melilotus alba (herb), 14. Neyraudia reynaudiana (grass), 15. Paederia foetida (vine, climber),

16. Pycnonotus jocosus (bird), 17. Rubus niveus (shrub), 18. Lespedeza cuneata (herb, shrub),


32

33

H. Invasive species in scrub/shrub lands:


4. Macaca mulatta (mammal), 5. Psittacula krameri (bird), 6. Caesalpinia decapetala (tree, shrub),


I. Invasive species in ice:


Jigme Singye Wangchuck National Park

Sprawling across 1723 sq km, Jigme Singye Wanchuck National Park is the second largest protected

area of Bhutan. Formerly known as the Black Mountain National Park, it has now been renamed after

the present and fourth monarch of Bhutan. The Park boasts of a variety of habitats, vast tracts of

primary forests and altitudes ranging from 200 m to 5000 m above sea level. There are sub-tropical

and broadleaf forests in its south, low conifer forests in its center and perennial snow on the high

peaks in its north. Situated in central Bhutan, Jigme Singye Wangchuck National Park is home to

about 395 species of birds including the endangered rufous-necked hornbill, Ward's trogon, Satyr

tragopan and white-bellied heron (Bhutan Trust Fund Bhutan Trust Fund for Environmental

Conservation, 2012).

Seven of the bird species that make this National Park their home are listed among the globally

endangered species. Rainfall varies too in different areas of the National Park and thus, this wildlife

sanctuary arbors wide diversity of climatic conditions, making it suitable for many different flora and

fauna species. Jigme Singye Wangchuck National Park has one of the highest coverage of mature fir,

pine and other types of broadleaf forests that are considered to be the one of the few virgin and

undisturbed tracks of forests in the Eastern Himalayas. The terrestrial fauna found here includes rare

and endangered species such as musk deer, Himalayan black bear, golden langur endemic to Bhutan,

clouded leopard, red panda and Royal Bengal tiger ("Jigme Singye Wangchuck National Park," 2012)

The eastern part of this National Park boasts of 20% of Bhutan’s tiger population and is said to be an

important link between the northern and southern tiger population in Bhutan. Phobjikha valley,

situated to the northwest of the park (which is considered to be the buffer zone of the park), is the

winter habitat of the black-necked cranes. More than 260 cranes migrate to this place every year in

winter. It is under the Royal Society for Protection of Nature. About 6000 people live inside the park

whereas about 15000 people are estimated to find their homes within 5 km periphery of the Park.

These people produce crops such as paddy, maize, wheat, buckwheat, millet and potato and raise

livestock consisting of cattle, yaks, sheep, horses and goats ("Jigme Singye Wangchuck National

Park," 2012).

The common invasive species found in Jigme Singye Wangchuck National Park are as follows:




34
































35

Royal Manas National Park

Situated in the south central Bhutan, Royal Manas National Park lies to the north of Manas National

Park in Assam, which is a World Heritage Site; and to the south of Jigme Singye Wangchuck

National Park. Royal Manas was declared a wildlife sanctuary in 1966 and thus, has the status of

being the oldest protected area in Bhutan. Later, it was upgraded to the status of being a National Park

and it became the first national park of Bhutan. Royal Manas National Park is one of the world’s few

sites that offer us stupendous variety of life forms and ecosystems. Royal Manas wildlife sanctuary

harbors thousands of animals and plant species including several globally endangered species (Bhutan

Trust Fund Bhutan Trust Fund for Environmental Conservation, 2012).

Sprawled across 1,023 km2, Royal Manas National Park with its adjoining India's Manas Tiger

Reserve and Jigme Singye Wangchuck National Park constitute one of the largest landscape level

protected areas in the eastern Himalayas. The Parks are full of tropical and sub tropical ecosystems

and have evergreen tropical forests, sub-tropical forests and warm and cool broadleaf forests. There

are about 45 species of mammals including gaur, extremely rare golden langur, Asian elephant, hispid

hare, clouded leopard, Royal Bengal tiger, gangetic dolphin, pangolin, Himalayan black bear, clouded

leopard, sloth bear and wild water buffalo in Royal Manas National Park ("Royal Manas National

Park," 2012).

About 366 species of birds have been recorded here including rare aerial fauna such as chestnut-

breasted partridge; great white-bellied heron, Palas fish eagle, blue-headed rock thrush, rufous-necked

hornbill and white-naped yuhina, spotted wren-babbler and emerald cuckoo. It is believed that about

200 species of other birds also make Royal Manas their home (Bhutan Trust Fund Bhutan Trust Fund

for Environmental Conservation, 2012).

Residents of Royal National Park are mostly farmers and in the past, tseri or slash-and-burn

cultivation had been practiced in here. Crops that grow here include maize, paddy, buckwheat, millet,

and foxtail millet while the cash crops include mustard, orange and cardamom. Bamboo and canes are

also found here in abundance.

Climatic variations in Royal Manas sanctuary are quite notable. There is about 5000 mm of rain

during monsoon season that lasts from May to September while rainfall in winter is quite negligible

and weather remains very pleasant from November till February. More than 900 types of plants are

there in Royal Manas and many of them have commercial, medicinal, traditional and religious

significance. WWF and Bhutan’s Nature Conservation Division are jointly running programs such as

providing training and equipments to the park staff, improving park infrastructure and supporting

biological and socio-economic surveys and park monitoring programmes ("Royal Manas National

Park," 2012).

The common invasive species found in Royal Manas National Park are as follows:







36

15. Suncus murinus (mammal), 16. Viverricula indica (mammal), 17. Corvus splendens (bird),

18. Dalbergia sissoo (tree), 19. Ficus microcarpus (tree), 20. Gallus gallus (bird)






D. Invasive species in wetlands:





E. Invasive species in riparian zones:






F. Invasive species in ruderal/disturbed:







19. Lotus corniculatus (herb), 18. Dalbergia sissoo (tree), 19. Ficus microcarpus (tree), 20. Gallus

gallus (bird)

37

Thrumshingla National Park

The newest national park of Bhutan, ThrumshingLa National Park gained this status in July 1998.

Sprawling across 768 sq km, it is situated in central Bhutan. Like all protected areas of Bhutan, it

presents diverse climatic conditions, habitats and altitudes that range from less than 1000 m to more

than 4000 m. This unique protected area presents vast biodiversity that includes alpine forests,

subtropical broadleaf forests and even rare plants. You may spot snow leopards, red pandas and tigers

prowling around in this National Park. It was in this Park that an image of a tiger was captured at

3000 m by a WWF-supported survey team in 2000. This photograph was the first evidence proving

that tigers do exist at such high altitudes too (Bhutan Trust Fund Bhutan Trust Fund for

Environmental Conservation, 2012).

Birdwatchers and ornithologists will find a lot of bird species to catch their attention and interest.

There are about 341 species of birds here including the endangered rufous-necked hornbill, beautiful

nuthatch, ward's trogon, white-naped yuhina and brown wood owl. Birdlife International has

recognized Thrumshingla National Park as an important Bird Area in the Sino-Himalayan mountain

forests. WWF supports the upkeep of the park to ensure that it has an effective management plan and

dedicated Park staff that can keep the pristine ecosystem here intact for generations to come. The park

has over 622 species thriving here quite well. Out of it, 21 species are endemic to this National park

and region ("Thrumshingla National Park", 2012).

Over 68 species of mammals have been recorded in this wildlife sanctuary including Bengal tiger,

leopard, leopard cat, rare clouded leopard, Himalayan black bear, red panda, musk deer, capped

langur and Malayan giant squirrel. Tourists and trekkers are attracted to Thrumshingla National Park

for trekking, chiefly because of its picture perfect scenery and it being one of the few natural habitats

of the world. Communities living within the confines of this Park earn their livelihood from the

tourism here. It is estimated that there are about 2000 people living within the park while 11000

people are estimated to live in its buffer zone. Overgrazing and human interference have evolved as a

serious threat to the forests of the Park in the present scenario ("Thrumshingla National Park", 2012).

The common invasive species found in different ecological habitats in Thrumshingla National parks

are as follows:













38





























39

Wangchuck Centennial Park

Wangchuck Centennial Park in northern Bhutan is the kingdom's largest national park, spanning

4,914 square kilometres (1,897 sq mi) over five districts, occupying significant portions of

northern Bumthang, Lhuntse, and Wangdue Phodrang Districts. It borders Tibet to the north and is

bound by tributaries of the Wong Chhu (Raidāk) basin to the west. Wangchuck Centennial directly

abuts Jigme Dorji National Park andBumdeling and Thrumshingla National Park in northern Bhutan,

and is further connected to Jigme Singye Wangchuck National Park in central Bhutan via "biological

corridors." Thus, most of northern Bhutan is part of these protected areas (Bhutan Trust Fund Bhutan

Trust Fund for Environmental Conservation, 2012).

Wangchuck Centennial was established on December 12, 2008 in honor of the Wangchuck dynasty,

founded in 1907. It contains headwaters of four major river systems: Punatsang Chhu, Mangde

Chhu, Chamkhar Chhu, and Kuri Chhu. Wangchuck Centennial also contains the various middle-

Himalayan ecological biomes, ranging from blue pine forests to alpine meadows, at altitudes from

2,500 metres (8,200 ft) to 5,100 metres (16,700 ft).

The park is home to over 200 species of vascular plants, 23 species of large mammals and over 100

bird species. Notable wildlife species inhabiting Wangchuck Centennial include the Bengal tiger

(Panthera tigris), snow leopard (Uncia uncia), wolf, takin (Budorcas taxicolor) and Himalayan black

bear (Selenarctos thibetanus) (Bhutan Trust Fund Bhutan Trust Fund for Environmental


The common invasive species found in different ecological habitats in Wangchuck Centennial park

are as follows:
















40


























41

Common invasive species in ecological habitats of Sanctuaries

Bomdeling Wildlife Sanctuary

Bomdeling Wildlife Sanctuary is situated in Trashi Yangtse district that lies in northwestern region of

Bhutan (Figure 4. Protected areas of Bhutan (source: Bhutan Trust Fund Bhutan Trust Fund for

Environmental Conservation, 2012).). It covers an area of 1545 sq. km, out of which 420 sq. km is

the buffer zone. It also covers parts of Lhuentshe and Mongar districts. The sanctuary touches Tibetan

region of China in the north and India in the northeast. There are about 100 species of mammals that

find sanctuary in this reserve including rare and globally endangered species such as Himalayan black

bear, musk deer, blue sheep, snow leopard, Royal Bengal tiger and red panda. From mid-November to

early March, it becomes a paradise for bird lovers as this nature reserve provides shelter to about rare

150 black-necked cranes in winter season every year (Bhutan Trust Fund Bhutan Trust Fund for

Environmental Conservation, 2012).

Children will love to spot a diverse variety of butterflies in Bomdeling Wildlife Sanctuary. About 130

species have already been recorded here and it is expected that 120 more species may be found here.

Natural beauty and sheer biological diversity makes this wildlife sanctuary worth a visit. You can also

see several important religious and cultural places such as Rigsum Gompa, the mystic Singye Dzong

and Dechenphodrang Lhaghang, which is believed to be the most picturesque monastery in the whole

country, situated inside this nature reserve. The Bomdeling Wildlife Sanctuary was established in

1995 with an aim to protect and preserve virgin Eastern Himalayan ecosystems ranging from warm

broadleaved forests to alpine and sub alpine habitats ("Bomdeling Wildlife Sanctuary," 2012).

It covers a part of what was previously Kulong Chhu National Park. In 1998, Bomdeling Nature Park

had a park manager and staff of its own and its first management plan was approved in 2001.

The altitudes vary throughout the sanctuary ranging from 1500 m above sea level in the south to over

6400 m above sea level in the north. Flat lands has been mostly cleared for villages and agricultural

land while most of the southern and lower part of Bomdeling sanctuary is covered with broadleaved

forests and has many ridges, valleys and river gorges. The central Bomdeling wildlife sanctuary

region has ridges and valleys that are covered with scrubland, conifer forest and broadleaved forest

and the northern part of the sanctuary is full of glacial lakes, valleys, scrubland, alpine pastures,

glaciers, snow peaks and slopes ("Bomdeling Wildlife Sanctuary," 2012).

The common invasive species found in different ecological habitats in Bumdeling Wildlife sanctuary

are as follows:








42




























43

Khaling Neoli Wildlife Sanctuary

The smallest protected area in Bhutan, Khaling Wildlife Sanctuary sprawls across 273 sq km. It is

situated in the Samdrup Jongkhar dzongkhag of the country and is an extended modification of the

former Neoli Wildlife Sanctuary. Thus, it is also referred to as Khaling Neoli Wildlife Sanctuary.

Situated on the southeastern border of Bhutan, Khaling Wildlife Sanctuary has Assam of India to its

east and south, River Nyera Ama Chhu to its west, and Martshala and Shingkhar Lauri geogs to its

north ("Khaling Neoli Wildlife Sanctuary," 2012).

There have been no notable protected area surveys conducted here yet the sanctuary is famous for

being a top-class habitat for the rare pygmy hog, Asian elephant and tiger. Other wild animals found

here are guar and hispid hares along with other tropical animal species. The major human settlements

in the sanctuary are Samrang and Daifam and human population is chiefly concentrated to the

southwestern and southeastern parts of the sanctuary. The sub-tropical forests in this sanctuary are

mainly divided into two forest reserves known as Khaling and Neoli and it is being planned to

combine them without changing the size (Bhutan Trust Fund Bhutan Trust Fund for Environmental


The Khaling reserve on the Assam side of the Indo-Bhutan border forms the trans frontier reserve.

The altitudes in Khaling Neoli wildlife sanctuary ranges from almost plain at 150 m to 1500 m and

the forest cover here consists of broadleaf evergreen forests, semi-evergreen rain forests, hill

evergreen subtropical forests and grasslands. The area has been marked by Birdlife International as

one of the important bird areas and the site for bird conservation in Bhutan and you may spot rare

avian fauna species such as chestnut-breasted partridge and rufous-necked hornbill ("Khaling Neoli

Wildlife Sanctuary," 2012).

The common invasive species found in different ecological habitats in Khaling Wildlife sanctuary are

as follows:













44















Phipsoo Wildlife Sanctuary

Sprawling across 278 sq km, Phipsoo or Phibsoo Wildlife Sanctuary is the only sanctuary in Bhutan

that has natural sal forests and is a prime habitat of Chital deer or the spotted deer Axis Axis. It lies

entirely inside Sarpang dzongkhag and touches the borders of Indian State of Assam in the south.

River Sunkosh Chhu flows to its west while it has Beteni geog in Tsirang dzongkhag in the north and

Hile geog in the east. Phipsoo wildlife sanctuary has mostly tropical and sub-tropical ecosystem and

vegetation. The rare and endangered animals that find their homes in this sanctuary include tigers,

Asian elephants, gaur and golden langurs (Bhutan Trust Fund Bhutan Trust Fund for Environmental


Phibsoo sanctuary is relatively uninhabited, though you can find some sparse human population

settled to its southwestern edge. It is about 50 km east of Phuentsholing. You can spot the rare

hornbill here. This wildlife sanctuary occupies an important position biogeographically and is fully

functional. Preliminary surveys of the flora and fauna have already been completed here while some

other surveys are still going on in the region. The World-wide Fund for Nature is providing support in

the conservation management programme of Phipsoo wildlife sanctuary and to ensure that the basic

conservation infrastructure is in place ("Phipsoo Wildlife Sanctuary," 2012).

The common invasive species found in different ecological habitats in Phibsoo Wildlife sanctuary are

as follows:






45




















F. Invasive species in ruderal/disturbed:







19. Lotus corniculatus (herb), 18. Dalbergia sissoo (tree), 19. Ficus microcarpus (tree), 20. Gallus

gallus (bird)

46

Sakteng Wildlife Sanctuary Sakteng Wildlife Sanctuary is an unusual one as it was created to preserve ‘Yeti’, the abominable

Snowman known as ‘Migoi’ by the locals. There are no scientific proofs confirming the presence of

this mythical creature that walks on two feet like humans and is tall and shaggy. There are many

folklores and urban legends about this creature in the local Bhutanese people who insist that there

have been many sightings of Migoi in this region. Migoi is known for its phenomenal strength,

magical powers such as the ability to become invisible and knowing how to walk backwards to fool

any trackers. The luxuriant deciduous forests of Sakteng are believed to be the home of these

creatures (Bhutan Trust Fund Bhutan Trust Fund for Environmental Conservation, 2012).

These forests have not yet been explored fully because entry of foreigners in this region is restricted

and locals do not venture too far into the jungles. Situated in the easternmost part of the Kingdom,

Sakteng Wildlife Sanctuary was declared a protected area in 2003, making it the newest protected

area if Bhutan. It sprawls across 650 sq. km, covering amazing biodiversity and variety of intact

Himalayan terrestrial ecosystems such as alpine meadows, temperate forests and warm broadleaf

forests. Keep your camera handy in the sanctuary, so that you are ready to click, in case you spot a

Yeti. Isolated nomadic tribes live in this sanctuary such as Brokpas. These indigenous tribal people

are often reticent and unwilling to interact with the outsiders ("Sakteng Wildlife Sanctuary," 2012).

The isolation of the place has preserved several life forms in their original shapes and sizes and there

are thick carpets of rhododendrons found here. You can spot snow leopards, red pandas, Himalayan

black bear, barking deer and Himalayan red fox here. Aerial fauna and birds include the hoary-bellied

Himalayan squirrel, Assamese macaw, blood pheasant, grey backed shrike, grey-headed woodpecker,

common hoopoe, rufous-vented tit and dark breasted rose-finch. Besides the conifers, plant life and

flora of Sakteng wildlife sanctuary includes rare blue poppies, Bhutan’s national flowers; primulas

and gentiana that burst into riot of colors in spring. Many plants such as cordyceps are of medicinal

value ("Sakteng Wildlife Sanctuary," 2012).

The common invasive species found in different ecological habitats in Sakteng Wildlife sanctuary are

as follows:










47


















Torsa Strict Nature Reserve The Torsa Strict Nature Reserve in Bhutan covers 609.51 square kilometres (235.33 sq mi) in Haa

District, occupying most of its area. It borders Sikkim and Tibet to the west and is connected to Jigme

Dorji National Park via a "biological corridor." Torsa contains the westernmost temperate forests of

Bhutan, from broadleaf forests to alpine meadows and the small lakes of Sinchulungpa, at altitudes

ranging from 1,400 metres (4,600 ft) to 4,800 metres (15,700 ft). Like Phibsoo Wildlife Sanctuary,

Torsa has no resident human population (Bhutan Trust Fund Bhutan Trust Fund for Environmental


The common invasive species found in different ecological habitats in Phibsoo Wildlife sanctuary are

as follows:









48

















Factors leading to introduction and spread of invasive species

Activities of the forest sector can contribute to the introduction and spread of invasive species through

forest utilization practices and the intentional introduction of species for commercial forestry,

agroforestry and other purposes.

Forest utilization, in particular practices such as timber harvesting, extraction of non-timber products,

the construction of logging and transport roads and facilities for logging camps, and the conversion of

natural forest to plantations, can have direct and indirect negative impacts on the ecological functions

of forests and on forest biodiversity by

promoting the invasion of alien species

(Asao, 1998).

Forest roads provide essential access for

timber extraction, management and

monitoring of forest resources and as such are

an important requirement for sustainable

forest management and use. However, when

poorly designed and maintained, forest roads

are often the cause of a variety of

environmental problems associated with

forest harvesting operations. Under some

circumstances, forest roads may also initiate

or accelerate the invasion of exotic species

that ultimately displace native species. In addition, the increased levels of human activities in

Figure 28. Construction of a forest road in Bhutan

49

previously inaccessible areas, as facilitated by forest roads, cause many environmental problems

including the possible introduction of alien

species (Kiritani & Moromoto, 2004).

Forest sector activities can promote the

emergence or re-emergence of infectious

diseases which degrade human health and that

of other species. Clear-cutting and road building

may increase exposure of workers to infectious

diseases such as human immunodeficiency virus

(HIV), Ebola hemorrhagic fever, and Marburg

hemorrhagic fever, yellow fever, leishmaniasis,

malaria and Ross River virus disease. Logging

can change the abundance, extent and quality

of aquatic larval habitats for the Anopheles mosquito vectors of malaria and by disturbing the forest

floor, creating depressions that catch and hold water, thus creating new sites for the development of

more mosquitoes (Kiritani, 2002).

Deforestation can result in humans coming into closer contact with the vectors for such diseases as

leishmaniasis, yellow fever, trypanosomiasis (both African sleeping sickness and Chagas disease),

and Kyasanur forest disease. Similarly, some animal reservoir hosts increase in abundance near the

edges between forests and human settlements thus increasing the risk of human exposure to

pathogens. The destruction of forest habitat may result in the removal, replacement or eradication of

dominant vector species and sometimes, the replacement species are more effective vectors of disease

as observed with loa loa (tropical eyeworm) and onchocerciasis (river blindness). Deforestation and

desertification may also be accompanied by changes in the distribution of vectors such as ticks,

blackflies, tsetse flies and Anopheles mosquitoes (Asao, 1998).

Forest workers, such as this worker in the tropical forests, can experience increased exposure to

infectious diseases and their vectors

Refforestation activities can also affect the population dynamics of vectors and reservoirs which can

promote the emergence of infectious diseases.

The forest sector itself is a major source of invasive species. Many of the tree species used in

commercial forestry in many parts of the world are alien or non-indigenous to the area. Hundreds of

species have also been widely and successfully planted for a variety of purposes including

afforestation, desertification and erosion control, and for the supply of fuelwood and other forest

products. Such intentional introductions however, can bring about many unintended and costly

consequences when these species escape cultivation and invade natural ecosystems. Alien tree

plantations can have negative effects on the biodiversity and water resources of afforested areas. Alien

species that spread from plantations to natural and semi-natural areas, and also into areas set aside for

conservation and water production, have considerable impacts on ecosystem properties and functions

(Kiritani & Moromoto, 2004).

Figure 29. Forest workers in tropical forest.

50

Impacts of Invasive Species

Impacts on ecosystem and Biodiversity

Plants form the biological foundation of all terrestrial and aquatic communities. Therefore, mass

invasions of alien plants more or less cause structural and functional changes in ecosystems, including

alterations in nutrients and/or structural condition. These changes in dominant plant species may lead

to the replacement of dominant plant consumers, followed by their predators, and further cause a

chain of changes in species compositions at every trophic level, and thus disrupt food webs and other

structural and functional features of the ecosystem(Washitani, 2004).

Even if the invasive species are pioneers dominating only early phases of the vegetation succession

sere, the effects of the invasion may last long through persistent soil seed banks. Invasive alien plant

species, when once established in an ecosystem, may cause irreversible changes by producing large

seed sources above and/or under the soil surface (Harper, 1977; Thompson & Grime, 1977;

Thompson, 2000). Soil seed bank strategies, using long persistent seeds and physiological

mechanisms to detect temporal ‘safe sites’ for seedling establishment are common to most invasive

alien species established in Japan(Washitani, 2004).

Flourishing invasive alien plants furnished with strategies enhancing spatial and temporal dispersal of

seeds inevitably lead alteration of the early stages of succession seres. This is likely to be one of the

most conspicuous influences of plant invasions on ecosystem processes (Washitani, 2004).

Status of study and implementation programs in Bhutan

The Department of Forest and Park services, a department within the Ministry of Agriculture and

Forest, are responsible for the overall protection and management of forests and wildlife resources of

Bhutan. It is one of the largest government organizations in Bhutan and a network of field offices

spread throughout the country. Within the department, the Nature Conservation Division is

specifically responsible for coordinating and technically backstopping nature conservation and

protected area management activities. The Nature Conservation Division has separate units for

conservation management planning, wildlife inventory, protected area extension, and the geographic

information system. A well-trained park manager administers each of national parks (Millennium

Ecosystem Assessment 2005). The 1995 Forest and Nature Conservation Act of Bhutan provides the

main legal framework for establishment and management of protected areas(Sherpa & Norbu, 1993).

National Biodiversity Centre (NBC), in April 2008 carried out a pilot project to study the invasive

alien plant species for a period of one year. The main objective of the pilot project study was to study

the potential threat to biodiversity by invasive alien plants. The studies are still continuing till present

day to find out what are the invasive species found in the country (Gyeltshen, 2008). Bhutan is also

one of the member nation to the Asia-Pacific Forest Invasive Species Network (APFISN), a network,

which has been established as a response to the immense costs and dangers posed by invasive species

to the sustainable management of forests in the Asia-Pacific region. APFISN is a cooperative alliance

of the 33 member countries in the Asia- Pacific Forestry Commission (APFC) - a statutory body of

the Food and Agriculture Organization of the United Nations (FAO). The network focuses on inter-

country cooperation that helps to detect, prevent, monitor, eradicate and/or control forest invasive

species in the Asia-Pacific region ("INVASIVES," 2007).

51

Conclusion

The ecosystems we manage as protected areas provide people with their most fundamental need. They

ensure the flow of high quality water to cities and rural farmers and settlements, irrigation works,

power plants, fisheries and navigation. Soil nutrients flow from them to adjacent food production

areas. Their wild genetic resources are being explored as the basic for future foods and medicines.

The sacred sites they contain harbour values critical to the spirituality of many individuals and

societies. Their wild environments and historic landscapes are providing solace to millions of visitors,

and helping to build personal character in our young people, and personal and cultural identity. These

areas also serve to integrate peoples, their economies and their cultures.

Today, these protected areas around the world are under many threats. The protected areas in Bhutan

are also under the similar global threats. These threats include those activities which are caused

mainly by human beings like forest fires, forest utilization, in particular practices such as timber

harvesting, extraction of non-timber products, the construction of logging and transport roads and

facilities for logging camps, and the conversion of natural forest to plantations, can have direct and

indirect negative impacts on the ecological functions of forests and on forest biodiversity. Such kinds

of activities lead to disturbaces and alterations of function in ecosystem. It leads to decline of

biodiversity and subsequently total loss or extinction of species.

One of such threat today in Bhutan like any other countries in around the globe, which has mainly

resulted from human interventions in nature, is the introduction of invasive species. Invasive species

invades niches which are away from its habitat and has ability to occupy other niches. It competes for

food and spaces with the native species. Mass invasions more or less cause structural and functional

changes in ecosystems, including alterations in nutrients and/or structural condition. These changes in

dominant plant species may lead to the replacement of dominant plant consumers, followed by their

predators, and further cause a chain of changes in species compositions at every trophic level, and

thus disrupt food webs and other structural and functional features of the ecosystem. The introduction

of invasive species has also caused decline to economic status, environmental harm and harm to

human health.

The study of invasive species, finding approximate number and their effect are under process. There

are over 200 invasive species including both plants and animals in the country, belonging mostly to

Compostae and Graminae families. However, the knowledge of invasive are new to Bhutan due to

which, currently a very few numbers of works are done to study it and essential mitigation activities

against it. Accordingly, the governmental organizations and non-governmental organizations in the

country are working hard to alleviate these factors and come to proper solutions

52

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INVASIVE SPECIES IN ECOLOGICAL HABITATS OF NATIONAL PARKS IN BHUTAN