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The past 40 years have seen dramatic increases in global production of soya, palm oil and other tropical export commodities

The global extent of several major tropical crops expanded markedly between 1961 and 20001

200 150 100 50 0

km2

Soya bean 76,297,000

Oil palm 9,707,000

Cocoa 7,156,000

Rice 151,198,000

Coffee 10,720,000

The total area (km2) cultivated for each crop in 2000 is given under each bar

SOURCES 1. Donald (in press) Conserv. Biol . 18. 2. Costanza et al . (1997) Nature 387: 253–260.

3. Balmford & Long (1994) Nature 372: 623–624. 4. O’Brien & Kinnaird (2003) Science 300: 587.

The potential impacts of genetically modified organisms remain unclear Genetic modification is already producing plants, animals and micro-organisms that can

ACKNOWLEDGEMENT Data kindly supplied by Paul Donald (Royal Society for the Protection of

Birds, UK).

3

Agricultural expansion is a major threat to birds, and appears to be increasing in importance

SOURCE Analysis of data held in BirdLife’s World Bird Database.

% of threats

The conversion of natural habitats to agricultural land is currently the most important threat to Globally Threatened Birds (see pp. 30–31). Agricultural expansion constitutes a higher proportion of all threats impacting Near Threatened species than it does for species in higher categories on the IUCN Red List (see figure). If the same Hunting and alien invasive species were the most frequent threats (61% of threats) for Extinct birds whereas for Near Threatened threatening processes birds, habitat loss through agricultural expansion is the most identified in recent frequently listed threatening process (57% of threats) assessments have been operating over a long period 100 of time, this indicates that pressures associated with Type of threat agriculture are set to 75 Other become increasingly Alien invasives important in the future. 50

Over-exploitation

25

Habitat loss/degradation (other) Habitat loss/degradation (agriculture)

ACKNOWLEDGEMENTS

Figures and text kindly provided by Jörn Scharlemann, Rhys Green (both Royal Society for the Protection of Birds and Conservation Biology Group, University of Cambridge, UK) and Andrew Balmford (Conservation Biology Group, University of Cambridge, UK).

What birds tell us about problems

% increase in area 1961–2000

250

In the past, over-hunting and alien invasive species were responsible for most bird species extinctions. Today, the greatest threat to biodiversity is habitat loss, particularly as a result of agricultural expansion, which is now threatening previously widespread and common birds ( box 3).

overcome the current limits on their growth and ranges. Such organisms could have big impacts on biodiversity, but this will depend on how they are used, in agriculture and other natural-resource sectors. For instance, they could reduce pressure for new habitat clearance by making already degraded land more productive. By contrast, they could allow agriculture to intensify to the detriment of those species that inhabit farmed land, and could also facilitate its expansion into today’s agriculturally ‘marginal’ but biologically important habitats, such as boreal forests and drylands.

PRESSURE

There have been significant recent increases in the areas under cultivation for many tropical commodity crops, including soya bean, oil palm, coffee, cocoa and rice1. Soya bean and oil palm have experienced the biggest growth, although the actual area under cultivation for these combined is still lower than that for rice alone. Soya bean and palm oil have become major commodities for consumption by the developed world, the latter being used in a great range of products from ice-cream to beauty treatments. Coffee and cocoa are major sources of income for developing countries, second only to oil in legal international trade1. Such land-use changes lead to drastic losses in biodiversity and ecological services from wild nature2,3. For example, Brazil alone has over 20,000 km2 of coffee plantation, most of it having replaced primary rainforest. In Indonesia, coffee planting is responsible for massive forest loss, even inside protected areas4. These land-use changes are linked to global trade rules and over-consumption in the developed world, which are thus partly responsible for large-scale habitat loss in high-biodiversity countries (see pp. 50–51).

Agricultural expansion is increasingly threatening species

State of the world’s birds 2004

2

0 Critically Endangered Vulnerable Near Extinct/ Threatened Extinct in Endangered the Wild

IUCN Red List Category

33

State of the world’s birds 2004  

State of the world’s birds provides information on how birds can be used to focus action and as indicators to monitor change. Using the most...

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