562 Land-Use Issues to permanently change land cover As the remote frontiers of the tropics, mountainous regions, and northern forests and tundras are exploited, settlement will likely increase and land will be transformed to a lasting urban state Europe can be viewed as a crystal ball for much of the earth’s future land use The forecast is for drastic simplification of a once diverse native land cover to one dominated by settlements, intensive agriculture, and fragmented vestiges of native habitat Effects of Land Use on Biodiversity The current extinction crisis is fueled, at a proximate level, by (1) habitat conversion, (2) habitat fragmentation, and (3) habitat degradation These are the most common reasons given to explain why modern species are at risk of extinction (IUCN (International Union for the Conservation of Nature), 1996) These three processes are the direct result of our land use and they function as the mechanisms that connect changing land cover to biodiversity (see Figure 1) Conversion of native land cover to agriculture and settlement is unquestionably the main cause of habitat loss on a global scale This conversion typically occurs in a piecemeal fashion and is associated with extensive road building that fragments habitat as it is being lost Native and converted habitats that are already utilized by humans are further degraded by agricultural intensification, resource extraction, and recreation A recent operational tool for policy support on the global to the national scale is the Global Biodiversity model GLOBIO (Alkemade et al., 2009) It can be used to assess (1) impacts of human-induced environmental drivers on land biodiversity in past, present and future, (2) the relative importance of the environmental drivers, (3) trends under future scenarios, and (4) effects of policy response options, such as climate change mitigation, plantation forestry, and protected areas GLOBIO has been applied in many integrated, global and regional environmental assessments (http://www.globio.info/home) Figure 11 is an example of an application of GLOBIO from the OECD Environmental Outlook 2030; it depicts the global trend in biodiversity over time The effects of land use on biodiversity can be illustrated by considering habitat conversion, fragmentation, and degradation in several regional studies, and we have selected well-documented studies to illustrate the general process It is important to consider regional changes in land cover because the factors that drive land use and link it to land cover are best understood at ‘subglobal’ levels (Kummer and Turner, 1994) The following sections examine (1) the complex ways that biophysical and socioeconomic factors affect land use, (2) the linkage between land use and habitat conversion, fragmentation, and degradation, and (3) the effects of land use on biodiversity Habitat Conversion Deforestation in Southeast Asia The tropical rain forests of Southeast Asia have declined dramatically since the end of World War II (in the late 1940s) Before humans arrived, the Philippines, Indonesia, Malaysia, Vietnam, and Thailand were completely forested (see Figure 3) Their rich dipterocarp forests were heavily logged (primarily for export) after the war ended The Philippines currently retains less than 26% of its original forest cover; Malaysia retains more forest, but it is being extensively harvested (Figure 12) The rates of deforestation in the Philippines are well documented and staggering (Collins et al., 1991; Kummer, 1992) From 1948 to 1987, 55% of the forest was lost From 1969 to 1988, the rate of deforestation was more than 2% per year – or every min! The latest FRA2010 reports for the year 2010 – 22% of the total land area in East Asia as being forest, 35% for South and Southeast Asia, 35% Biomes Tropical grassland and savannah Temperate grassland and steppe Historic and future development of global biodiversity 100 Mean species abundance (%) Tropical rain forest 80 Tropical dry forest Mediterranean forest, woodland and shrub 60 Temperate broadleaved and mixed forest Temperate coniferous forest 40 Boreal forest 20 Desert Tundra Polar Potential 1700 1750 1800 1850 1900 1950 Baseline Figure 11 Historical trends in global biodiversity Reproduced from OECD (2008) 2000 2050