Protected areas and freshwater provisioning: a global assessment of freshwater provision, threats and management strategies to support human water security

1. Protected areas, although often terrestrially focused and less frequently designed to protect freshwater resources, can be extremely important for conserving freshwater biodiversity and supporting human water security necessary for people to survive and thrive. 2. This study measured the quantity of water that is being provided by protected areas to areas downstream, and how threatened protected areas are in terms of their water provision. 3. Building on a Freshwater Provision Index, the numbers of people who live downstream from these protected areas around the world were then assessed. The same process was applied to areas where there are no protected areas. 4. Protected areas deliver 20% of the global total of approximately 40 000km(3) year(-1) of continental runoff. More than one-quarter of water provisions supplied by the world's protected areas are exposed to low levels of threat and less than 10% are exposed to high levels of threat; this is compared with higher levels of threat for provisions from non-protected areas, where nearly one quarter of the provisions are exposed to high threat and only 10% are exposed to low threat. 5. Nearly two-thirds of the global population is living downstream of the world's protected areas as potential users of freshwater provisions supplied by these areas. Despite the overall large volume of low-threat water supplied by protected areas, globally 80% of the downstream human community users receive water from upstream protected areas under high threat, and no continent has less than 59% of its downstream users receiving water from upstream protected areas under high threat. 6. Globally, increased attention to reduce the threats to fresh water in areas under protection, as well as designation and management of additional areas, are needed to safeguard freshwater flows, and support biodiversity conservation and the provision of freshwater ecosystem services. Copyright (C) 2016 John Wiley & Sons, Ltd.