Around 1 billion in the middle of the 19th century, the world’s human population is now closer to 7 billion. Tis exponential growth rate and congruent rise in consumption is having a dra- matic impact on our planet (CBD 2010). Approximately 40% of the world’s natural forests have disappeared in the last 300 years (FAO 2006); since 1900 the world has lost about 50% of its natural wetlands, including carbon-rich peatlands (Moser et al. 1996); the rate of species extinctions attributable to hu- man activities is estimated to be 1,000 times more rapid than historical natural extinction rates (MEA 2005a); and the rate of biodiversity loss continues unabated (Butchart et al. 2010). Tis while it is becoming increasingly clear that loss of biodiversity tends to reduce overall ecosystem productivity and resilience, and there is growing evidence that the maintenance of multiple ecosystem processes requires large numbers of species (Naeem et al. 2009). Tus it is important to protect flora and fauna not only for their intrinsic value, but also for the many supporting ecosystem services they provide, many of which contribute di-
rectly to human well-being. Te overall effect of rapid human population growth and consumption is that approximately 60% of the world’s ecosystem services, such as clean water, food, timber, climate regulation, protection against natural hazards, erosion control, recreation and medicinal sources, have been severely degraded in just the last 50 years (MEA 2005a). Te peatlands where the highest densities of orangutans are found are among the most important carbon sinks on the planet. In fact, Indonesian peatlands store 54 Gt of carbon, more than any other tropical country (Joosten 2009).
Te tropical rainforest, one of the richest ecosystems on the planet, has been the most impacted, with high forest loss, degra- dation and fragmentation occurring in just the last few decades (FAO 2010). Tis has been no different in Indonesia, which has seen one of the highest forest loss rates in the world and large acceleration in forest loss during the last five years (FAO 2010). Tese changes adversely affect the many ecosystem services that
A typical forest view in North Sumatra (Perry van Duĳnhoven)