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Modern agricultural methods and technologies brought spectacular increases in food
production, but are also a primary cause of habitat loss and ecosystem destruction (Til-
man
et al
., 2002). Clearance for cropland or permanent pasture has already reduced the
extent of natural habitats on agriculturally usable land by more than 50% (Green
et al
2005), and much of the rest has been altered by temporary grazing (Groombridge and
Jenkins, 2002). Habitat modification already affects more than 80% of globally threat-
ened mammals, birds and plants (Groombridge and Jenkins, 2002), with implications
for ecosystem services and human well-being. Of the world’s land, cosatal and ocean area,
only 13%, 6% and less than 1%, respectively, are within protcted areas (WDPA, 2010).
Despite its crucial role for providing ecosystem services agricul-
ture remains the largest driver of genetic erosion, species loss and
conversion of natural habitats (MA, 2005). Globally over 4,000
assessed plant and animal species are threatened by agricultural
intensification (IUCN, 2008). A central component in avoiding
loss of biodiversity and ecosystem services, such as water, from ex-
panding agricultural production and resource extraction is to limit
the trade-off between economic growth and biodiversity by stimu-
lating to agricultural productivity and more efficient land use.
Most global scenarios project increased use of land for arable
crops and grazing. Scenarios from the Global Environmental
Outlook, The Millennium Assessment and the Global Biodi-
versity Outlook all show increases of land use as a result of a
growing population and increased economic development.
Further enhancement of agricultural productivity (‘closing the
yield gap’) and reduction of post harvest losses are key factors
in reducing the increased need for land and, consequently, the
rate of biodiversity loss (CBD, 2008). These options should be
implemented carefully in order not to cause new undesired
negative effects, such as emissions of nutrients and pesticides,
as well as risks of land degradation. An increase in protected
areas and change towards more eco-agricultural cropping sys-
tems and sustainable meat production could have immediate
positive effects on both biodiversity and water resource man-
agement, while increasing revenues from tourism.
A reduction of crop- and pasture land can only be achieved if dras-
tic changes in diets are assumed. Some of these more extreme
scenarios are presented by Wise
et al
. (2009) and Stehfest
et al
.,
(2009). They suggest that if enhanced agricultural productivity
is assumed and the consumption of meat is greatly reduced then
large areas will become available for forest and natural grassland
recovery. Some scenarios also predict a shift of agricultural pro-
duction towards different regions, resulting in a reduction of ag-
ricultural land in, for example, Europe. Recovery of biodiversity
is possible on abandoned land, but the rate and quality depend
on actions taken on these lands. In models like GLOBIO this
factor is not yet incorporated at this stage. Autonomous recov-
ery is a slow process and is represented by the land use category
‘secondary forest’ in GLOBIO (Alkemade
et al
., 2009). Restora-
tion activities for example plantations may speed up the recovery
process, but are not included in the GLOBIO model.
GLOBAL LANDUSE CHANGE
AND SCENARIOS OF
BIODIVERSITY LOSS