ALPINE PLANT BIODIVERSITY

Part II Functions and Threats

H.J.B. Birks

NOMA 2011

ALPINE PLANT BIODIVERSITY

Ecosystem services in alpine habitats

Functional significance of alpine biodiversity

Threats to alpine biodiversity

Conclusions

Acknowledgements

ECOSYSTEM SRVICES IN ALPINE HABITATS

Three main types:

1. Provision services – extractable resources that primarily benefit lowland populations (water for drinking, irrigation, timber) and ecosystem production (crops, medicinal plants)

2. Regulatory and support services – biodiversity, watershed and catchment protection, soil fertility, soil as store of water and carbon

3. Cultural services – spiritual role of mountains, biodiversity (biophilia), recreation, cultural and ethnological diversity.

Ecosystem services in alpine habitats globally

Alpine Montane Hills/PlateauxTerr Aq Terr Aq Terr Aq

Downslope safety

Safety +++ - +++ - + -Dams +++ + + + + -

Water Freshwater +++ +++ +++ +++ + +Energy +++ +++ +++ +++ + +

Food Grazing ++ - +++ - +++ -Crops - - +++ + ++ ++

Fibres Fuel - - ++ - ++ -Timber - - ++ - ++ -

Medicinal Wild +++ - +++ - + -Cultivars - - +++ - + -

Cultural Recreation ++ + ++ ++ +++ +Spiritual +++ + ++ + + +Ethnology +++ - +++ - ++ -

- not relevant; + relevant; ++ important; +++ very important

Will vary from area to area (e.g. European Alps, Himalaya, Andes)

Körner et al. (2005)

Human population in mountains

Population (x 103)

Percent of total

Density (per km2)

Asia 597,714 49% 65.2

Former USSR 34,851 3% 6.4

South America 173,549 14% 37.7

North Africa 141,113 12% 52.3

Central Africa 119,559 10% 18.3

Europe 152,613 13% 43.1

Total 1,219,399 100% 38.2

World population 6 billion, so global mountain population (1.2 billion) is about 20% of total global population.

Data from Körner et al. (2005)

FUNCTIONAL SIGNIFICANCE OF ALPINE BIODIVERSITY OR

WHY IS ALPINE BIODIVERSITY SO IMPORTANT?

1. Catchment slopes depend on soil stability

2. Soil stability depends on near continuous plant cover

3. Plant species diversity ensures a sustained plant cover and hence soil stability

4. Biodiversity therefore provides insurance – intact systems provide insurance against system failure (Körner 2002)

5. Ecosystem functioning (plants, animals, micro-organisms co-existing and functioning together)

6. Cultural heritage argument – diverse, man-made ecosystems are historical treasures of our society

7. Ethical aspects (the right of all species to exist)

8. Aesthetic values (the beauty of alpine plants)

Concentrate on ‘Körner’s Insurance of Intact Systems' Idea

Alpine terrain (alpine + montane) covers 24% of the global land area

All mountains have slopes, sometimes very steep slopes

Slopes (and the peaks behind them) not only capture water but channel it to the foothills and, via large river systems, feed the lowland plains

Mountains therefore provide water for half of mankind, directly or indirectly. Hold about 66% of world's freshwater as snow or ice

Runoff and associated sediment load are beneficial (water supply, mineral nutrients) and also non-beneficial (floods, mud-flows, etc.)

Slopes are the key to so much of alpine landscape ecology

1. Provide gravitational power to water, some of which can be converted to electric energy (hydroelectric power)

2. Guard, guide, constrain, or endanger traffic routes for people and animals

3. Stop clouds (advection) or create clouds (convection)

4. Exert mechanical forces on organisms

Unless made of solid rock, the only way loose substrates are secured to slopes is through VEGETATION.

Alpine vegetation provides the 'screws' and 'nails' that maintain slopes and prevent slope dangers and disasters.

Slopes are only as stable and safe as the integrity and stability of their vegetation.

Körner (2002)

Integrity of alpine up-slope vegetation is thus the basic core or control of much, if not all, of down-slope lowland welfare and society in many parts of the world.

Easy to forget basic link between remote mountains and densely populated lowlands.

Recurring floods in China and mud slides in Philippines or Andes are result of uncontrolled up-slope instability.

Much lowland productivity is required to support the needs of up-slope society and to maintain sustainable management in the uplands.

Down-slope Up-slope interdependencies

"Lowland – Upland Contract of Society" (Körner 2002)

Needs the effectiveness of alpine vegetation, natural or cultural, to control slope and soil erosion.

Körner (2004)

Intact alpine vegetation provides slope safety.

As there are many risks and threats on slopes, require many SAFEGUARDS.

Threats include damage by heavy rain or hail, surface run-off, mechanical sheer of loose ground, exploitation of deep-substrate moisture, over-trampling and grazing by herbivores, snow-gliding, etc.

Plants with their range of life-forms and growth habits provide the safety 'tools' and 'services'. At any time these may fail because of natural disease, divergent life cycles, senescence, stress, disturbance, and chance factors.

Need all key 'tools' to be present in various combinations at all times to provide 'emergency' help, to maintain ecosystem 'services'.

Not really known if ecosystems with more species are less at risk of loss of integrity than systems with less species.

Depends on absolute numbers of species

identity, growth-form, and ecology of species

environmental conditions

Insurance hypothesis proposes that one of the benefits of biological richness is that it insures against system failure.

Functional redundancy may not play any role for long time periods but a single extreme event can cause functional redundancy to be the 'safety mechanism' of fragile alpine slopes.

Alpine slopes are very susceptible to extreme events. Maintaining alpine biodiversity (microbes to herbivores) is thus a high priority as alpine slopes and their stability are so important globally for the 'Lowland – Upland Contract of Society'.

Functional diversity of species are Nature's insurance against system failure (loss of substrate on mountain slopes) and secures, at the same time, other 'services' such as- provision of medicinal plants, food, fodder, fibres, and other montane forest products- clean run-off water- attractive landscapes

How many species are needed to ensure ecosystem integrity and slope stability?

Answer depends on the time-frame but the more the better is a safe generalisation.

We do not know what future disturbances and stresses will be. Best to play safe now!

As gravity does not compromise or cease, there is little hope for repair once alpine slopes are damaged and 'wounded'

May take thousands of years for new soils to develop in an eroded landscape. End-result of slope damage may be bare rock.

Grabherr (1997)Mountain desert, Andes, S America

Central Tibet, 4520 mMiehe et al. (2008)

Ghimire (2008)

Rokaya et al. (unpublished)

Peak of medicinal plant richness about 1000 m but medicinal plants (up to 100 species) occur up to 6000 m (e.g. Rheum nobile, Saussurea spp.)

Major topic in itself – several books

Emphasises the central role of medicinal plants in Himalayan ecosystem services

Jha et al. (2008) Ghimire et al. (2008)

Evidence for human-induced dwarfing of Saussurea laniceps in the Himalaya

Decline in height of S. laniceps since 1900

Height of plants at heavily harvested and low harvest sites – 9cm smaller

Law & Salick (2005)

Nepal Biodiversity Plan 2004

Unique in recognising people as part of the systems from lowlands to alpine summits

Ram P. Chaudhary

POTENTIAL THREATS TO ALPINE BIODIVERSITY

Last 100 years

Decline of traditional grazing practices has resulted in regrowth of scrub and forest. Tree-lines have risen in the last 50 years - ? land-use changes or climate changes or both.

Hydroelectric development, flooding of valleys, and river regulation.

Tourism, trampling, ski centres, use of artificial snow, mining -generally rather localised.

In northern areas, lichen- and bryophyte-rich vegetation has declined because of trampling and too much or too little grazing. Perhaps also because of changes in atmospheric inputs as a result of 'global change'.

Reports on seedling establishment and shift of tree-line in last 50-100 years

Area Since Shift (m) Genus

Chile 1850 10 Nothofagus

NW Canada 1850 10-20 Picea

N Urals 1920 100-500 Larix

New Zealand (South Island)

1950 10 Nothofagus

Sweden 1960 120-375Betula, Picea,

Pinus

Spain 1955 70 Fagus

Australia 1967 15 Eucalyptus

Bulgaria 1950 130 Pinus

Oregon, USA 1980 10 Abies

Montana, USA 1973 10-15Abies, Picea, Pinus, Larix

Global Change

Körner (1998)

In last 150 years, atmospheric CO2 concentrations and global temperatures have increased, as have atmospheric nitrogen levels.

Are alpine plants responding to these changes?

Jotunheimen mountains of central Norway

24 mountains surveyed in 1930-1931 by Reidar Jørgensen

Re-located over 400 of his localities in 1998

Could see how flora had changed in 68 years

Kari Klanderud and John Birks

Galdhøppigen, Norway

Map of Jotunheimen, central south Norway, showing the 25 mountains studied by Jørgensen (1933) and this study. Three local glaciers are indicated by stars.

Klanderud & Birks (2003)

>2,000 m

1,800 – 2,000 m

1,600 – 1,800 m

Changes in species numbers

1930-31

1998

Little change

Big increase

Some increase

Klanderud & Birks (2003)

Some plants have extended their altitudinal limits in last 70 years by 200-300 m.

1. Dwarf-shrubs –

Phyllodoce caerulea Vaccinium myrtillus

Empetrum nigrum Vaccinium vitis-idaea

Salix lapponum

2. Grasses –

Festuca vivipara Deschampsia flexuosa

Phyllodoce caerulea, Norway

Vaccinium myrtillus Norway

Vaccinium vitis-idaea Swedish Lapland

Empetrum nigrum Norway

Salix lapponum Scotland

Some summit plants have declined in frequency in last 70 years (e.g. Saxifraga cespitosa, Cerastium alpinum, Erigeron uniflorus, Ranunculus glacialis).

Decline because of direct warming or, more likely, increased competition from faster-growing species expanding from lower altitudes.

Saxifraga cespitosa Norway

Cerastium alpinum Norway

Erigeron uniflorus Norway

Similar floristic changes reported from Swiss and Austrian Alps, the Swedish mountains, north-east Greenland, and Glacier National Park, Montana.

Long-term future for high alpines is not good if they continue to decline, even on the highest mountains in the Alps or Scandinavia.

If global change and global warming continue to the extent predicted by climatologists, the Alpine World will be a very different place in 2100 compared to 2008.

Many species may have gone extinct or be committed to extinction because of climate warming, loss of specialised habitats (e.g. snow-beds), the absence of anywhere higher or cooler to spread to, and competition from larger, faster growing dwarf-shrubs and grasses that are rapidly moving upwards in response to climate warming.

Thuiller et al. (2005)

Attempt to assess species status by 2080 under various future climate scenarios. Main drivers are temperature and moisture changes.

Excess species loss (red) in Alps, Pyrenees, central Spain, Balkans, Scandinavia, Carpathians, and Corsica.

Alpine flora 60% loss

Four different climate scenarios

EU scale extinction Local scale extinction

AT=Austrian Alps, FR=French Alps, CHB=Swiss Central Alps1, AP=Apennines, IPE=Pyrenees1, CHV=Swiss Western Alps, NO=Norway, P=Pyrenees2, SCO=Scotland, CAR=Carpathians, CHZ=Swiss Central Alps2

Extinction rates generally >10%. At local scale, highest extinctions are predicted to be Pyrenees1 & Scotland

MRI (2007)

Projected warming by 2055 in alpine and arctic areas according to IPCC Fourth Assessment Report. Average of five climate predictions under two different future scenarios

Nogués-Bravo et al. (2008)

Order of temperature change (1=high, 13=low)

2055 2085

Northern Asia 1 1

N American Arctic 2 2

European Arctic 3 4

Central Asia (Himalaya, etc) 4 3

N Africa 5 6

N American Rockies 6 5

European Alps 7 7

N and Central Andes 8 9

Equatorial Africa 9 8

South Africa 10 10

Low Asia (e.g. Borneo) 11 11

Southern Andes 12 12

Australia/New Zealand 13 13

Why is there little or no evidence for local extinction of high-altitude species?

Need to assess an alpine landscape not at a climate-model scale or even at the 2 m height of a climate station, but at the plant level.

Use thermal imagery technology to measure land surface temperature.

Körner 2007 Erdkunde

Scherrer & Körner 2010 Global Change Biology

Scherrer & Körner 2010 Journal of Biogeography (in press)

Land-surface temperature across an elevational transect in Central Swiss Alps shown by modern thermal imagery. Forest has a mean of 7.6°C whereas the alpine grassland has a mean of 14.2°C. There is a sharp warming from forest into alpine grasslandKörner (2007)

In two alpine areas in Switzerland (2200-2800 m), used infrared thermometry and data-loggers to assess variation in plant-surface and ground temperature for 889 plots.

Found growing season mean soil temperature range of 7.2°C, surface temperature range of 10.5°C, and season length range of >32 days. Greatly exceed IPCC predictions for future, just on one summit.

IPCC 2°C warming will lead to the loss of the coldest habitats (3% of current area). 75% of current thermal habitats will be reduced in abundance (competition), 22% will become more abundant.

Scherrer & Körner (2010 in press)

Warn against projections of alpine plant species responses to climate warming based on a broad-scale (10’ x 10’) grid-scale modelling approach.

Alpine terrain is, for very many species, a much ‘safer’ place to live under conditions of climate change than flat terrain which offers no short distance escapes from the new thermal regime.

Landscape local heterogeneity leads to local climatic heterogeneity which confers biological resilience to change.

In Himalaya, highest known vascular plants are

Saussurea gnaphalodes at 6400 m

Ermania himalayensis at 6300 m

Arenaria bryophylla at 6180 m

Highest stand of vegetation (9 species) at 5960 m

Highest closed sward of vegetation at 5500 m

Often sharp transition at 5500 m, plants become much more sparse. Potentially 900 m available for occupation today (assuming no climate change), about 6°C

Photos: Toshio Yoshida

Upland Land-Use and Biodiversity

Montane and alpine areas have been subject to land-use, particularly grazing, for many thousands of years.

Not a new factor.

Problems arise when the tolerable dose is exceeded by over-stocking and over-grazing.

Who knows what the tolerable dose is?

Who knows the point of no return?

Who knows what is sustainable, in the sense that the system remains intact?

Traditional shepherds knew of course, but this knowledge has been lost or was never incorporated into any management plan for alpine and montane areas.

Plans based on lowland areas are almost certainly not applicable to upland areas. Potential disaster! Des

Thompson

Many montane and low-alpine areas in Alps, Carpathians, Caucaus, Hindu Kush, Himalaya, South Africa, Tibet, Karakorum, Altai, Scotland, and possibly Scandinavia are man-made ecosystems or 'cultural landscapes' from many thousand years of utilisation.

Cultural heritage – wooden fences, stone walls, shrines, wooden or stone dwellings, drainage and irrigation systems, very specialised flora and fauna, etc.

Traditional and thus commonly sustainable management very rarely leads to erosion.

These traditional land-uses are currently disappearing due to population growth, increasingly intense agriculture, and large extension of land-use areas for marginal economic gain.

Result - major changes in ecosystem functioning & biodiversity

Essential to secure sustainable agriculture in traditional alpine areas near the tree-line so as:

1. to conserve biologically highly diverse, stable, and attractive plant communities

2. to maintain a healthy, unpolluted food and water source for future generations

3. to retain part of our cultural heritage

4. to ensure soil stability and water supply for down-slope human communities

Things can go wrong in three ways:

1. uncontrolled, non-traditional (patchy) grazing, causing spot-impacts under otherwise low stocking rates

2. over-stocking beyond carrying capacity or introduction of excessively heavy cattle

3. sudden abandonment of pastures

Can all affect soils and induce slope erosion

Introduction of invasive species can also be a major threat in some areas. Such species grow faster and out-compete native, slow-growing alpines (e.g. New Zealand).

Millennium Ecosystem Assessment

MEA (2005)

Major threats in alpine areas world-wide

1. Habitat and land-use change

2. Climate change (global warming)

3. Invasive introduced species

4. Over-exploitation (agriculture, grazing, hydro-electric development)

5. Pollution (nitrogen phosphorus)

also

6. Recreation (e.g. ski development)

Potential threats different in different alpine areas, a point not really emphasised by MEA

North America

South America

European Alps

Turkey & Iran

Introduced species + ++ - -

Land-use changes - + ++ ++

Hydroelectric development

+ - + +

Ski development + + + +

Atmospheric nitrogen deposition

++ - ++ -

Global warming ++ + ++ +

Over-exploitation - + - ++

++ = high threat + = some threat - = no likely threat

AustraliaNew

ZealandEast

AfricaSouthern

AfricaHimalay

aChina

Introduced species + ++ - + - -

Land-use changes + - ++ ++ ++ ++

Hydroelectric development - - - + - +

Ski development + + - - - ?

Atmospheric N deposition - - - - - +

Global warming + + + ++ ++ ++

Over-exploitation - - ++ ++ ++ ++

++ = high threat + = some threat - = no likely threat

Threats in Drakensberg Mountains, Southern Africa

3% in Lesotho and 97% in Natal Drakensberg are protected as Nature Reserves, National Parks, and Wilderness Areas.

Major threats by overstocking and soil erosion in Lesotho.

Also threats from invasive exotic plants and clearance for crops in an area very poorly suited to arable agriculture in Lesotho.

At present alpine areas (nearly all in Lesotho) are unprotected.

Urgent need for whole areas as Biosphere Reserve or World Heritage Site.

But conservation is not the major problem facing southern Africa……

Besides problems of overstocking, soil erosion, and hydroelectric development in Lesotho, major threat is from 'global warming'.

McDonald et al. (2002) defined climate envelopes for 16 alpine species today, to define the modern 'alpine' climate.

McDonald et al. (2002)

Predicted the extent of the 'alpine' climate under future scenario of IPCC for 2150.

See major reduction in 'alpine' climate, confined to the few highest areas. Would become very fragmented. Major loss of species.

Much reduced snow cover, loss of available water. Major ecological and economic effects. Lesotho’s ‘economy’ depends on selling its water to South Africa. What is there is less water and more soil erosion?

Disaster!

Nepal Biodiversity Plan 2004

Recognises people as part of the systems from lowlands to alpine summits

Ram P. Chaudhury

Because of land-use changes and hence habitat loss and also deliberate collecting in 19th and early 20th century, some alpine species in Europe are locally extinct.

Major attempts by conservation bodies to re-introduce species in Scotland, Sweden, Switzerland, and elsewhere.

So-called 'Species Action Plans'.

Species Action Plans in Europe

Pinguicula alpina, Norway

Extinct in UK

Local in Alps and Scandinavia

Woodsia ilvensis, ScotlandNearly extinct in UK

Locally common in central and eastern Norway

Saxifraga cotyledon,

Norway

Nearly extinct in Sweden but common in

Norway

Saxifraga hirculus, Yukon

Nearly extinct in Switzerland

but common on Svalbard

Conservation in High Mountains globally

Mountain Park* (number)

Area (106 ha)

Afro-tropical 42 20.4

Antarctica 15 3.2

Australian 3 2.6

Indo-Malayan 42 7.2

Neo-arctic 96 153.8

Neo-tropics 103 34.5

Oceanic islands 8 3.6

Palaeo-arctic 164 39.1

Total 473 264.5

*IUCN Management Categories I-IV, with at least 1500 m relief and minimum size of 10,000 ha

Körner et al. (2005)

Global Mountain Biodiversity Assessment

www.unibas.ch/gmba

Within the Global Mountain Diversity Assessment, change in emphasis from diversity in ‘pristine’ alpine areas to a recognition of alpine areas as ‘cultural landscapes’

2002 2006

“Highlands are more valuable in terms of resources of medical plants than lowlands”

Aditya Purohit, India

“Mountain crop systems: below the tree-line high-altitude agro-ecosystems become more reliable with spatially diverse crop rotational cycles”

Alejandro Camino, Peru

“When poverty is the driver of human life in the uplands, how can we guarantee sustainable land use? Mountain economies must create added value beyond the production of raw materials if they are to survive.

Mohamed Saleem, Ethiopia

“An important human dimension of global mountain biodiversity is the diversity of the human species itself. Indigenous populations seem to have better functional capacity than newcomers when measured in terms of traits such as health, physical work capacity, and reproductive success, that are important for long-term success. Andean and Tibetan populations have different physiological adaptations to high altitude and illustrate biodiversity in this sense.”

Cynthia Beall, USA

“We cannot separate people from nature anymore”

Fausto Sarmiento, USA

CONCLUSIONS

1. Alpine plant biodiversity is higher than one would expect on a simple species:area relationship.

2. Some alpine areas are particular 'hotspots' of biodiversity.

3. Alpine biodiversity declines at a remarkably constant rate with elevation (about 40 species decrease per 100 m).

4. High alpine biodiversity in certain areas appears to be a result of many factors, including centuries of low-intensity land-use, topographical isolation, and high geological and topographical diversity.

5. Alpine biodiversity is globally important because of the importance of stable alpine slopes and the 'Lowland – Upland Contract' for society.

6. There are many potential threats to alpine biodiversity. The most important are land-use changes, global warming and atmospheric nitrogen deposition, and invasive species.

7. Species re-introduction plans are in progress in parts of Europe, as part of 'species action plans'.

8. Mountain biodiversity is not only a scientific theme of great interest, but also it is perhaps the best 'indicator value' of the integrity of mountain ecosystems.

9. As a cultural heritage, diverse alpine grazing areas deserve more attention and respect. They are of real and potential value ecologically, economically, and aesthetically.

ACKNOWLEDGEMENTS

Ram P. Chaudhury Hilary Birks Harry Jans

Khem Raj Bhattarai Christian Körner Ian Green

Ole Reidar Vetaas Kari Klanderud Des Thompson

John-Arvid Grytnes Oriol Grau Bill Baker

The late Derek Ratcliffe Peter ErskineJohn Grimshaw

Mark Hanger Guido VittoneCathy Jenks

Royal Botanic Garden Edinburgh Herbarium Staff

Alpine Garden Society and Scottish Rock Garden Club members

for help, sharing data, ideas, and pictures, and for help in preparing these lectures