Geography of habitat loss ~ Conservation Biology

Some regions of the Earth are far more affected by habitat destruction than others. Among the most imperiled are the so-called “biodiversity hotspots”, which contain high species diversity, many locally endemic species (those whose entire geographic range is confined to a small area), and which have lost at least 70% of their native vegetation (Myers et al. 2000). Many hotspots are in the tropics. The Atlantic forests of Brazil and rainforests of West Africa, both of which have been severely reduced and degraded, are examples of biodiversity hotspots. Despite encompassing just a small fraction (<2%) of the Earth’s land surface, hotspots may sustain over half of the world’s terrestrial species (Myers et al. 2000). Many islands have also suffered heavy habitat loss. For instance, most of the original natural habitat has already been lost in Japan, New Zealand, Madagascar, the Philippines, and Java (WRI 2003).

Other islands, such as Borneo, Sumatra, and New Guinea, still retain some original habitat but are losing it at alarming rates (Curran et al. 2004; MacKinnon 2006). Most areas of high human population density have suffered heavy habitat destruction. Such areas include much of Europe, eastern North America, South and Southeast Asia, the Middle East, West Africa, Central America, and the Caribbean region, among others. Most of the biodiversity hotspots occur in areas with high human density and many still have rapid population growth (Cincotta et al. 2000).

Human populations are often densest in coastal areas, many of which have experienced considerable losses of both terrestrial habitats and nearby coral reefs. Among others, coastal zones in Asia, northern South America, the Caribbean, Europe, and eastern North America have all suffered severe habitat loss (MEA 2005). Finally, habitat destruction can occur swiftly in areas with limited human densities but rapidly expanding agriculture. Large expanses of the Amazon, for example, are currently being cleared for large-scale cattle ranching and industrial soy farming, despite having low population densities (Laurance et al. 2001). Likewise, in some relatively sparsely populated areas of Southeast Asia, such as Borneo, Sumatra, and New Guinea, forests are being rapidly felled to establish oilpalm
or rubber plantations (MacKinnon 2006; Laurance 2007; Koh and Wilcove 2008). Older agricultural frontiers, such as those in Europe, eastern China, the Indian Subcontinent, and eastern and midwestern North America, often have very little native vegetation remaining.