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Confronting a biome crisis - Mariabelen Segovia
Transcript of Confronting a biome crisis - Mariabelen Segovia
What is a Biome?
A large, relatively distinct terrestrial region with similar climate, soil, plants, and animals, regardless of where it occurs in the world.
What can we do?
Differences between the biomes
Ecoregions at risk
Deforestation from logging has led to a loss of habitat for many organisms, and can lead to the disappearance of entire forests. Humans depends on wood for fuel, paper, clothes and furniture. Deforestation also increases the amount of carbon dioxide in the atmosphere. Acid Precipitation, which comes from humans burning fossil fuels to make energy causes harmful destruction in forests. The precipitation does not directly kill the trees, but it weakens them and harms their leaves. They get less nutrients, are poisoned and they are more susceptible to death from diseases and insect attacks. Climatologists predict that 50-90% of Coniferous forests will disappear in the next 50 years.
How can human impact affect the biomes: coniferous forests?
Confronting a biome crisis
http://www.marietta.edu/~biol/biomes/boreal.htm http://www.blueplanetbiomes.org/taiga.htm Miller, G. Tyler and Spoolman, Scott. "Living in the Environment.16th Ed. Belmont:Brooks/Cole Cengage Learning 2009. Images from: Wikipedia.com
The loss of individual species
The extinctions are symptomatic of a global-scale biome crisis that threatens biodiversity loss, ecological dysfunction and consequent impacts to human lives and economies.
The terrestrial biomes and ecoregions are at great risk because of disparities in the extent of habitat loss and protection.
As humans convert natural habitats, the world's biodiversity and ecosystems are degraded, and biodiversity and the benefits we derive from it are put at risk.
Habitat protection can mitigate this risk, but only if protected areas are distributed in a way that represents the ecosystems at risk and helps to sustain ecological function.
The biomes are divided according to local geography and climate, and are different from one another by the unique assemblages of species and ecosystems found within them.
The diversity of species and ecosystems across biomes and ecoregions reflects the remarkable outcomes of biodiversity's evolutionary history and sets the stage for its future.
In tropical forest biomes, evolution has given extraordinary taxonomic diversity, while the dessert ecosystems, is selected for organisms uniquely able to live through extreme heat and drought.
The world's biomes and ecoregions continue to sustain essential ecological functions that support biodiversity. They also provide valuable ecosystem services such as erosion control and water retention that help sustain agriculture and human populations.
The value of these ecosystem services has been estimated at $33 trillion US per year.
As human activity degrades the world's biomes, we not only shorten the list of species that inhabit the world, but we diminish the variety of landscapes, ecological interactions and evolutionary pressures that sustain biodiversity, evolve new species in the future and generate ecosystem services that benefit people.
The global extent and distribution of habitat protection were evaluated by summarizing the 2004 World Database on Protected Areas (WDPA Consortium 2004) to calculate the per cent area of each biome and ecoregion covered by a designated protected area.
The WDPA is the most comprehensive global catologue of protected areas, and includes data about their sizes and locations. Protected areas in categories I-IV were explicitly designated for biodiversity protection while those in categories V-VI were designated with multiple management objectives.
Materials and Methods
Globally, 21.8% of land area has been converted to human-dominated uses. Habitat loss has been most extensive in tropical dry forests, temperate broadleaf and mixed forest, temperate grasslands and savannas and Mediterranean forests, woodlands and scrub.
Meanwhile, tundra and boreal forest biomes remain almost entirely intact.
Results: Biomes and risk
The world's network of protected areas covers 11.9% of all terrestrial land area.
Habitat protection is more concentrated in temperate conifer forests and montain grasslands. Tundra and the flooded grasslands and savannas are also relatively well protected. Temperate grasslands and savannas, and Mediterranean forests and scrub are the least protected biomes.
Biomes with intermediate levels of habitat conversion have greater habitat protection, while those with very high levels of land conversion have only limited protection.
However, it is disturbing that so little has been protected in biomes in which 30-50% of habitat area has already been lost.
Certainly, as more habitat is converted, there is less habitat left to protect.
The relationship between habitat conversion and protection among ecoregions is negative (slope= -0.18), suggesting a general tendency for protection efforts to decline the larger proportions of ecoregions that are converted to human-dominated uses.
To identify at-risk or crisis ecoregions, we calculated the Conservation Risk Index in every ecoregion and categorized them as VULNERABLE, ENDANGERED or CRITICALLY ENDANGERED.
>50% --> Critically Endangered
This analysis reveals a biome crisis emerging from substantial disparities between habitat loss and protection across ecoregions and at a global scale, across entire biomes.
The map of crisis ecoregions yields a more specific perspective on where biodiversity are at great risk and identifies biomes (temperate grasslands and Mediterranean Scrub)within the conservation action should be focused.
Map of Crisis Ecoregions
For years now, we have been alerted about the crisis of species loss, especially in tropical rainforests. But, this analysis suggests that the tropical rainforest biome is a relatively lower risk compared to at-risk biomes such as Mediterrean forests, woodlands and scrubs that also contains thousands of species diversity and endemism.
This analysis draws particular attention to biomes and ecoregions where species, communities and ecosystems are all at risk because of disparities in habitat loss and protection.
This analysis not presume to redefine the global conservation priorities, concluding that the urgency of the biome crisis should weigh heavily alongside considerations of ecological diversity, and the vulnerability and irreplaceability of unique species.
Work in progress
In 2003, the World Parks Congress celebrated expansion of the world's protected area network over the past decade, while highlighting the need for better representation of the world's biomes and ecoregions.
This public-private partnerships promise to advance comprehensive conservation efforts at the global scale necessary for confronting the biome crisis.
In 2004, The Convention of Biological Diversity affirmed their commitment to complete designation of national networks of protected areas by 2010.
In 2010, a consortium of private conservation organizations (Birdlife International, Conservation International, Greenpeace, The Nature Conservancy, Wildlife Conservation Society, WWF) pledged their support for completing systematic conservation plans and management effectiveness of protected areas.
Jonathan M. Hoekstra and Timothy M. Boucher: Global Priorities Group, The Nature Conservancy
Taylor H. Ricketts and Carter Roberts: Conservation Science Program, World Wildlife Fund