Available at Areas of High Biodiversity Under Threat Gwen Raitt Biodiversity and Conservation Biology

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Areas of High Biodiversity Under Threat

Gwen Raitt

Biodiversity and Conservation Biology

Department

BCB 705:Biodiversity

In previous chapters the loss of biodiversity was considered. Logically, in view of this loss, steps must be taken to preserve biodiversity. So how does one preserve the maximum amount of biodiversity?

Here four factors are highlighted for consi-deration in developing conservation strategies:

The distribution of biodiversity,

The immediacy of the threat of loss,

The representation of all species, habitats, ecosystems, etc. in protected areas,

The cost of conservation action.

In this chapter the following concepts are mentioned: megadiverse (or megadiversity) countries, ecoregions and hotspots.

The chapter focuses on the hotspot concept.

Retaining Biodiversity

See the notes for the names of the countries.

Megadiverse Countries

The term ‘ecoregion’ is used by Bailey, Omernik and the United States branch of the World Wildlife Fund (US-WWF).

Bailey defined ecoregions as areas representing groups of ecosystems that function in a similar way.

Omernik defined ecosystems as areas that show similar mosaics of ecosystems, environmental resources and human impacts.

The US-WWF’s terrestrial ecoregion was defined as “relatively large units of land containing a distinct assemblage of natural communi-ties and species, with boundaries that approximate the original ex-tent of natural communities prior to major land-use change”. This definition was generalised (now ecoregion not terrestrial ecoregion) to include water and expanded by adding “ecological dynamics, and environmental conditions”.

The ‘Global 200’ is a prioritization scheme that evaluates the ter-restrial, freshwater and marine realms using ecoregions. The ‘Glo-bal 200’ identified 238 ecoregions as priority conservation areas.

Ecoregions

The US-WWF base their terrestrial ecoregions on existing biogeo-graphic schemes with modifications based on expert opinion but no existing scheme is used consistently. In the United States, US-WWF follow Omernik’s scheme.

Omernik’s scheme is not congruent with the vegetation patterns.

The use of different existing biogeographic schemes in different places at the finest scale raises the question of the repeatability of the methods used.

New schemes like the US-WWF’s ecoregions may weaken conserva-tion efforts by:

Taking money that could be used for field conservation,

Implying that the science conservation efforts were based on is somehow inferior.

From the literature (see the notes), US-WWF is hard selling ecore-gions which, in my opinion, makes the science involved suspect.

Ecoregions (2)

The term ‘hotspot’ is used to define many different things.

In conservation biology, the term may refer to a geographical area in which any or any combination of the following traits is unusually high: species richness, levels of endemism, numbers of rare or threatened species, levels of taxonomically unusual species or intensity of threat.

Biodiversity hotspots were originally defined by Dr. Norman Myers as areas with unusually high species concentrations and high ende-mism levels which are exceptionally threatened with destruction.

This definition was later refined to areas with unusually high ende-mism (defined using vascular plants as areas containing a minimum 0.5 % of the earth’s plant species as endemics) that are experiencing extremely high rates of habitat loss.

25 biodiversity hotspots were defined using the re-fined definition.

9 new hotspots have been suggested since.

Hotspots

Roberts et al. (2002a, b) started the process of delineating marine hotspots by analysing coral reefs using 69 lobster species, 662 snail species, 804 coral species and 1 700 reef fish species (a total of 3 235 species).

Endemism and risk of habitat loss (because the information on habitat loss was unavailable) were used to identify 18 centres of endemism and 10 coral reef hotspots.

This analysis is not comprehensive, even for coral reefs.

No coral reef cryptofauna were included in the study by Roberts et al. (2002a, b).

The temperate and polar systems have not been considered but are seriously threatened.

Most of the centres of endemism and coral reef hotspots adjoin terrestrial hotspots.

It would be worthwhile to expand the terrestrial conservation actions to include marine areas.

Hotspots (2)

Map taken from Myers et al. (2000).

Map of the 25 Biodiversity Hotspots from 2000

This hotspot originally covered 293 804 km2 but only about 73 451 km2 is still primary vegetation.

Known biodiversity:

Vascular plants: 3 488 spp. (2 124 spp. endemic),

Mammals: 157 spp. (18 spp. endemic),

Birds: 340 spp. (8 spp. endemic),

Reptiles: 69 spp. (4 spp. endemic),

Amphibians: 46 spp. (25 spp. endemic),

Freshwater fish: 73 spp. (15 spp. endemic).

This hotspot is threatened by invasive alien species, logging, strip mining, oil extraction, the expansion of croplands and pastures and overpopulation.

Human density: 121 people/km2

The California Floristic Province


Known biodiversity:







This hotspot is threatened by logging, the unsustainable use of non-timber products, agricultural expansion and increased fire frequencies resulting from the use of fire to stimulate pasture.


The Madrean Pine-Oak Woodlands

This hotspot originally covered 1 130 019 km2 but only about 226 004 km2 is still primary vegetation.

Known biodiversity:



Birds: 1 113 spp. (208 spp. endemic),




This hotspot is threatened by oil extraction, mineral extraction, timber extraction, road building which allows access to undisturbed areas, overpopulation and poverty which result in forest clearing for crops and pastures.


Mesoamerica

This marine hotspot stretches from Yucatan (Mexico) south to Colombia and is thus adjacent to the terrestrial Mesoamerica and Caribbean Hotspots.

The coral reefs cover about 4 127 km2.

Of the 3 235 species studied, this marine hotspot has:

430 widespread species,

20 endemic species occur.

The threat score is 1.91.

The threats include global warming and disease.

The Western Caribbean Marine Hotspot


Known biodiversity:







This hotspot is especially threatened by alien invasive species. Other threats include agricultural expansion, mining, charcoal production and tourism.


The Caribbean


Known biodiversity:







This hotspot is threatened by timber and firewood extraction, aquaculture, agriculture and infrastructure, hunting, plantations, mining, proposed road construction and development and invasive alien species. Human population growth adds to the pressure.


The Tumbes-Chocó-Magdalena


Known biodiversity:







This hotspot is threatened by invasive alien species, poverty, human population growth, seasonal burning, pastures, croplands, mining, firewood extraction, road and dam construction, deforestation, oil exploration and development and mining.


The Tropical Andes


Known biodiversity:







This hotspot is threatened by invasive alien species, overgrazing, deforestation, the illegal wildlife trade, fire and human population growth causing urbanization (including facilities for tourism, road building and hydroelectric complexes).


The Chilean Winter Rainfall–Valdivian Forests


Known biodiversity:







This hotspot is threatened by industrial forestry (logging and plantations), crops and pastures partially caused by poverty, urbanization caused by human population growth, pollution from heavy industry and charcoal and firewood extraction.


The Atlantic Forest


Known biodiversity:







This hotspot is threatened by human population growth, cropland and pasture expansion, the development of infrastructure (e.g. roads, railways and hydropower plants) and charcoal production.


Cerrado


Known biodiversity:







This hotspot is threatened by illegal species collection, mining, overgrazing and both dryland and irrigated agriculture and the infrastructure (e.g. dams) needed for irrigation.


Succulent Karoo


Known biodiversity:





Amphibians: 46 spp. (16 spp. Endemic),


This hotspot is threatened by invasive alien species, urbanization and agriculture.


Cape Floristic Province


Known biodiversity:







This hotspot is threatened by croplands and pastures, plantation forestry using exotic species, urbanization, invasive alien species, localized titanium mining and charcoal production .


Maputaland-Pondoland-Albany

This marine hotspot stretches from Natal to East London and is thus nearest to the terrestrial Maputaland-Pondoland-Albany Hotspot.

The coral reefs cover about 178 km2.





The threats include fishing, pollution from on land and tourism.

The Eastern South Africa Marine Hotspot

This marine hotspot includes the islands of La Réunion, Mauritius and Rodriguez (but not Madagascar) and is thus adjacent to the terrestrial Madagascar and the Indian Ocean Islands Hotspot.

The coral reefs cover about 205 km2.





The threats include coastal development, overfishing, pollution from agriculture esp. sugar cane and a growing human population.

The Southern Mascarene Islands Marine Hotspot


Known biodiversity:







This hotspot is threatened by human population growth (Mauritius has about 538 people/km2 ), crops and pastures, timber extraction and plantations, hunting and invasive alien species.


Madagascar and the Indian Ocean Islands


Known biodiversity:







This hotspot is threatened by agriculture, urbanization, charcoal production, firewood collection, timber extraction (especially near tourist areas), the uncontrolled use of fire and mining.


The Coastal Forests of Eastern Africa


Known biodiversity:







This hotspot is threatened by overgrazing, uncontrolled hunting, shifting agriculture, charcoal production and the development of infrastructure.


Horn of Africa

This marine hotspot covers the Red Sea. This includes the Gulfs of Aqaba and Suez and the inner part of Gulf of Aden and is thus adjacent to the terrestrial Horn of Africa Hotspot.






The threats include coastal development, industrial deve-lopment and tourism in the adjacent countries.

The Red Sea Marine Hotspot


Known biodiversity:







This hotspot is threatened by human population growth, crops, pastures, plantations, logging, the overexploitation of non-timber forest products, fire, mining, firewood collection, charcoal production, medicinal plant collection, hunting and disease.


Eastern Afromontane

This marine hotspot includes the Islands of Bioko, São Tomé, Principe and Annobon and is thus adjacent to the terrestrial West African Forests Hotspot.

The area covered by coral reefs is not available.





The threats include coastal deve-lopment, overfishing, sedimenta-tion from logging, and a potential coral harvesting business.

The Gulf of Guinea Marine Hotspot


Known biodiversity:







This hotspot is threatened by political instability, poverty, human population growth, logging, agriculture, hunting, mining and infrastructure development (particularly roads).


West African Forests

This marine hotspot is restricted to the Cape Verde Islands and is thus adjacent to the terrestrial Mediterranean Hotspot.

The area covered by coral reefs is not available.





The threats include coastal development, overfishing and pollution from the land.

The Cape Verde Islands Marine Hotspot


Known biodiversity:







This hotspot is threatened by overgrazing, urban expansion, tourism (including infrastructure development), human population growth and agricultural intensification, water shortages and desertification.


Mediterranean Basin


Known biodiversity:







This hotspot is threatened by illegal timber cutting for fuel, overgrazing and poaching.


Caucasus


Known biodiversity:







This hotspot is threatened by agricultural development (particularly irrigation and its associated dams), overgrazing, excessive firewood collection, mining, military operations and human population growth.


Irano-Anatolian


Known biodiversity:







This hotspot is threatened by human population pressure, logging, plantations, agriculture, infrastructure development, overgrazing, hunting, firewood, non-timber forest product extraction, forest fires, unregulated tourism, poaching and invasive alien species.


The Western Ghats and Sri Lanka

This marine hotspot includes Lakshadweep, the Maldives, southern India and Sri Lanka and is thus adjacent to the terrestrial Western Ghats and Sri Lanka Hotspot.



1 053 widespread species,



The threats include over-fishing, the live fish trade, coral mining and global warming.

The Northern Indian Ocean Marine Hotspot


Known biodiversity:







This hotspot is threatened by human population growth, overgra-zing, poaching, unregulated plant collection, firewood extraction, agriculture, fires, settlement expansion, infrastructure development, mining, war, minefields, dams, irrigation and global warming.


The Mountains of Central Asia


Known biodiversity:







This hotspot is threatened by human population growth, logging, crops, pastures, fire, settlements, overgrazing, overexploitation of medicinal plants, firewood collection, non-timber product extraction, tourism, political unrest and poaching.


The Himalaya


Known biodiversity:







This hotspot is threatened by high population growth, logging, firewood collection, building construction, pastures, overgrazing, dam building, mining, road building, uncontrolled tourism development, collection of traditional medication and illegal hunting.


The Mountains of Southwest China


Known biodiversity:






Freshwater fish: 1 262 spp. (553 spp. endemic).

This hotspot is threatened by human population growth, fire, planta-tions, logging, firewood collection, charcoal production, mining, wet-land drainage, dams, aquaculture, tree planting on mudflats, over-fishing, destructive fishing techniques and the wildlife trade.


Indo-Burma


Known biodiversity:







This hotspot is threatened by logging, agriculture, rubber production, pulp production, non-timber forest product harvesting, oil palm plantations, military and police activities, road construction, mining, fires, the wildlife trade and political developments.


Sundaland

This marine hotspot stretches from West Java east to Kepulauan Tanimbar and is thus adjacent to the terrestrial Sundaland and Wallacea Hotspots.






The threats include intensive destructive fishing, pollution from land and an expanding live fish trade.

The Sunda Islands Marine Hotspot


Known biodiversity:







This hotspot is threatened by commercial logging, crops and pastures, timber plantations, land settlement schemes, fire, mining development, hunting and poaching.


Wallacea


Known biodiversity:







This hotspot is threatened by invasive alien species, severe rural poverty, logging, mining, land conversion and the country’s development objectives.


The Philippines

This marine hotspot includes the Philippine archipelago and is thus adjacent to the terrestrial Philippines Hotspot.






The threats include overfishing, the use of explosives and poison to in fishing, polluted runoff from the land caused by agriculture, logging and urban development.

The Philippines Marine Hotspot

This marine hotspot includes the Ryukyu Islands, Southern China and Taiwan and is thus adjacent to the terrestrial Japan and Philippines Hotspots.






The threats include coastal development, global climate change and plagues of crown-of-thorns starfish.

The Southern Japan, Taiwan and Southern China Marine Hotspot


Known biodiversity:







This hotspot is threatened by invasive alien species, development of ski resorts and golf courses, road development, wetland drainage for agriculture, river channelisation, plantation forestry and urban development.


Japan


Known biodiversity:







This hotspot is threatened by invasive alien plant species, logging, agriculture, urbanization and commercialization, hunting, trapping and fire. Rising sea levels threaten low-lying islands.


Polynesia/Micronesia


Known biodiversity:







This hotspot is threatened by human population growth, invasive alien species, logging, clearing for plantations, agricultural expansion, mining and poor governance .


East Melanesian Islands


Known biodiversity:







This hotspot is threatened by invasive alien species, nickel mining, bush fires, logging, hunting and the illegal collection of selected animals for trade.


New Caledonia


Known biodiversity:







This hotspot is threatened by invasive alien species and massive habitat destruction in the form of deforestation, ecosystem degradation and wetland drainage.


New Zealand


Known biodiversity:







This hotspot is threatened by invasive alien species, agriculture, bush fires (used in hunting and land clearing) and mining (which causes habitat destruction and water pollution).


Southwest Australia

The main threats to the biodiversity hotspots are human population growth, economic development and invasive alien species.

Prioritization schemes require regular updating because circum-stances change.

All the forms of prioritization considered in this chapter provide indications of where conservation effort is necessary. This is good but it must be translated into action on the ground before conservation benefits.

It is not a good idea to waste money (and time) on developing new prioritization and/or representation schemes instead of actually conserving biodiversity. New prioritization and/or representation schemes are especially wasteful of resources if other such schemes already exist.

Conservation planners are not usually the ultimate decision makers.

Prioritization and representation are not enough to bring about conservation. Other actions are required to achieve conservation.

Concluding Remarks

Links to Other ChaptersChapter 1 Chapter 1 Biodiversity: what is it?Biodiversity: what is it?

Chapter 2 Chapter 2 The evolution of biodiversityThe evolution of biodiversity

Chapter 3 Chapter 3 Biodiversity: why is it important?Biodiversity: why is it important?

Chapter 4 Chapter 4 Global biodiversity and its declineGlobal biodiversity and its decline

Chapter 5Chapter 5 Biodiversity: why are we Biodiversity: why are we losinglosing it? it?

Chapter 6Chapter 6 Extinction: past, present, future Extinction: past, present, future

Chapter 7Chapter 7 Areas of high biodiversity under Areas of high biodiversity under threat threat

I hope that you found chapter 7 informative.

Documents

Available at Areas of High Biodiversity Under Threat Gwen Raitt Biodiversity and Conservation Biology