INTRODUCTION – ECOSYSTEM SERVICES
Ecosystems and our natural environment constitute the platform upon which our entire existence is based (Costanza et al., 1997). The services on which we depend include not only the air that we breathe and the joy of wildlife, but form the very basis of our food pro- duction, freshwater supply, natural filtering of pollution, buffers against pests and diseas- es and buffers against disasters such as floods, hurricanes and tsunamis. The MA (2005) described four catagories of services, provisioning, regulating, supporting and cultural.
An Ecosystem is the dynamic complex of plant, animal and micro-organism communities and the nonliving environment interacting as a functional unit. It assumes that people are an integral part of ecosystems (MA, 2005). Ecosystem Services are the benefits that people obtain from ecosystems. They can be described as provisioning services (e.g. food, water, timber); regulating services (e.g. regulation of climate, floods, disease, waste and water quality); cultural services (e.g. recreational, aesthetic and spiritual) and supporting services (e.g. soil forma- tion, photosynthesis and nutrient cycling) (MA, 2005).
Ecosystems ensure pollination, so crucial for agricultural pro- duction (Allenwardell et al., et al., 1998; Brown and Paxton, 2009; Jaffe et al., 2010), estimated at 153 billion USD in 2005 (Gallai et al., 2009) and it includes supply of water not only for irrigation and household use, but also for cooling in indus- trial processes, dilution of toxic substances and a transporta- tion route (UNEP, 2010). It is also critical to health, not only through water supply and quality and through natural filter- ing of wastewater (UNEP, 2010). 80 % of people in developing countries rely on traditional plant-based medicines for basic healthcare (Farnsworth et al., 1985) and three-quarters of the world’s top-selling prescription drugs include ingredients de- rived from plant extracts” (Masood, 2005), providing a string of services from rich to poor alike, but with particular value to the impoverished (Sodhi et al., 2010; UNEP, 2009).
Pest control is another key ecosystem service underpinned by biodiversity; it seems to be greatly determined by the abun-
dance of natural enemies present to counter the pest species involved, such as in coffee production (Batchelor et al., 2005; Johnson et al., 2010). Although biological systems are complex, improved pest control is often founded on a diversity of natural predators, and non-crop habitats are fundamental for the sur- vival and presence of these biological control agents (predators, parasitoids) (Zhang et al. 2007). Landscape diversity or com- plexity, and proximity to semi-natural habitats tends to produce a greater abundance and species richness of natural enemies (Balmford et al. 2008, Bianchi et al. 2006; Kremen & Chaplin- Kramer 2007; Tscharntke et al. 2007).
Global change will alter the supply of ecosystem services that are vital for human well-being (Schröter et al., 2005). Without
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