Tradeoffs in Management of Freshwater Ecosystem Services Under International Environmental Conventions: The Case of Inland Waters Fisheries

摘要

Humans rely heavily on freshwater systems for a variety of ecosystem services (ES) such as clean water supplies; foodprodiiction; commercial fishing (provisioning ES), nutrient assimilation (regulating ES), flood control (supporting ES) and recreation (cultural ES) (MEA 2003). Pressures on freshwater systems to provide multiple ecosystem services, particularly those of water supply and waste assimilation, have led to high rates of biodiversity loss (Revenga and Kura 2003). Further, interlinked activities, such as physical changes in the nature of inland freshwater systems, modification of water regimes, influx of invasive species, fisheries management and harvest, water pollution; eutro-phication and climate change have contributed to the declinesin inland biodiversity and fisheries resources over the past few decades (Post et al. 2002; Allan et al. 2005; Finlayson et al. 2005). Recent evidence suggests that fish and invertebrates within inland aquatic ecosystems comprise 40-70% of the known species classified at a minimum of being vulnerable to extinction (WRI 2000; Revengaand Kura 2003; Finlayson et al. 2005). Future scenarios suggest that tradeoffs between increases in food production, water availability and nutrient input will further exacerbate the decline in production of freshwater services, such as in biodiversity and fisheries production (MEA 2005a).