The Environmental Food Crisis

ECOSYSTEM SERVICES Ecosystems have been described as the life support system of the Earth – for humans as well as all life on this planet (MA Health Synthesis Report 2005). Ecosystem services, the bene- fits that humans derive from ecosystems, are considered “free”, often invisible, and are therefore not usually factored into de- cision-making. This chapter discusses the role of the diverse forms of living species – biodiversity – in food production, fo- cusing on agriculture and marine capture fisheries, as these provide the bulk of global food production. Agriculture (livestock and foodcrops) require a range of con- ditions for optimum productivity. These conditions are gener- ated by natural ecological components and processes as well as through artificial enhancement. Water resources for agriculture are highly dependent on natu- ral ecosystems and biodiversity, in particular vegetation such as forests in terms of flow regulation. This is crucial for providing a dependable water supply to crop areas, such as through reten- tion of water in wetlands and forests buffering both droughts and floods (Bruijnzeel, 2004; UNEP, 2005). At present 75% of

globally usable freshwater supplies comes from forested catch- ments (Fischlin et al ., 2007), therefore water is critically linked to forests. These ecosystems also help buffer global climate change (Nepstad et al ., 2007). Genetic diversity plays a critical role in increasing and sustain- ing food production levels and nutritional diversity. Diverse organisms contributing to soil biodiversity perform a number of vital functions that regulate the soil ecosystem, including de- composition of litter and cycling of nutrients such as nitrogen. Crop rotations or agroforestry increase yield stability and soil fertility; grassland and pasture/crop systems tend to be more sustainable because they provide opportunities for rotation di- versity. Biodiversity may create “pest suppressive” conditions and greater resistance to invasion of farming systems by nox- ious species. Pollinators are essential for the production of a large number of crops (e.g., cereal, orchard, horticultural and forage production), and contribute to improvements in qual- ity of both fruit and fiber crops; this service is ensured by an abundance and diversity of pollinators, in large part provided by wild biodiversity. Pest control is another key ecosystem service underpinned by biodiversity; it is greatly determined by the abundance of natural enemies of the pest species involved.Improved pest control is dependent on a diversity of natural enemies of pests, and non- crop habitats are fundamental for the presence and survival of these biological control agents (predators, parasitoids) (Zhang et al ., 2007). Landscape diversity or complexity, and proximity to semi-natural habitats tend to produce a greater abundance and species richness of natural enemies (Bianchi et al ., 2006; Kremen and Chaplin-Kramer 2007; Tscharntke et al ., 2007; Balmford et al ., 2008). Thus, the main threat to the provision of biological control as an ecosystem service seems to be habitat loss and degradation, now exacerbated by potentially disruptive climate change. Indeed, Balmford et al ., (2008) suggest that there is a medium to high probability that the provisioning of biological control is subject to thresholds/tipping points in the foreseeable future (by 2025), particularly in regions of very in- tensively managed agriculture.

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