A boost for freshwater conservation

A boost for freshwater conservation

Systematic conservation planning—a data-driven process for prioritizing biodiversity conservation resources—has been strongly biased over the past two decades toward terrestrial and marine species and systems (1). Freshwater ecosystems, which are among the most threatened on Earth, have received less attention. Wetland extent is estimated to have declined globally by nearly 70% since 1900 and, on average, freshwater vertebrate populations declined by 84% between 1970 and 2016 (2). There is an urgent need for prioritizing resources toward freshwater conservation. On page 117 of this issue, Leal et al. (3) show that such prioritizations need not be a zero-sum game: Integrated cross-realm conservation planning can, for a negligible reduction in terrestrial benefits, increase freshwater benefits up to 600%.

These results are important because, at this moment, the global conservation community is setting targets for the next 30 years. The Convention on Biological Diversity (CBD) is defining its Post-2020 Global Biodiversity Framework, to replace the expiring Aichi Biodiversity Targets. There is an opportunity with the renewed CBD framework to create a policy environment and commitments designed to “bend the curve” of freshwater biodiversity loss (4).

Leal et al.‘s findings, from their studies in Pará, Brazil, are of particular relevance to two targets in the draft framework, which will be negotiated during the first quarter of 2021 and finalized at the 15th meeting of the Conference of the Parties to the CBD, scheduled for May 2021. One target aims for a proportion of global land and sea areas to be under spatial planning, as a precursor to protecting and restoring natural ecosystems. The second aims for a proportion of the planet to be conserved using a combination of conventional protected areas and other effective area-based conservation measures (5). The formulation of these targets may yet change, but the underlying intent will likely remain: We need to protect more of our planet than we currently do, and we need to use spatial planning to guide that protection.

The Amazonas Lowlands ecoregion contains a rich and diverse fauna. The main types of vegetation include seasonally flooded forests. There are strong ecological links between the aquatic and terrestrial habitats. Rivers and forests supply multiple ecosystem services to the communities living in the region.


Historically, protected areas have been designed and managed first for terrestrial ecosystems and their species, with freshwater considered as an afterthought, if at all. For example, at least 1249 large dams are located in protected areas, with the processes of “downgrading, downsizing, and degazettement” having legalized dam construction within many of these areas (6). A study of continental Africa (7) showed that the proportion of freshwater species whose ranges are substantially covered by protected areas and Ramsar sites (wetlands designated to be of international importance under the Ramsar Convention) is much smaller than for birds or mammals. Globally, about 70% of river reaches (by length) have no protected areas in their upstream catchments, rendering them partly conserved at best (8). These and other shortfalls can be traced back in part to a lack of freshwater-focused conservation planning and investment (1).

At the same time, as Leal et al. rightly observe, conventional protected areas are no silver bullet for conserving freshwater biodiversity. Instead, they are part of a toolbox of options that should also embrace a growing set of strategic adaptive management approaches for freshwater protection. Among these options is area-based protection of systems beyond protected areas, including lands with collective tenure rights for indigenous peoples and local communities.

Recommendations already exist for integrating freshwater conservation priorities into larger landscape strategies, in particular through entire watershed management plans (9, 10). The International Union for Conservation of Nature’s approach for identifying freshwater Key Biodiversity Areas (KBAs), which then serve as spatial conservation planning inputs to critical site networks, is one applied example [e.g., Lake Victoria, East Africa (11)]. These holistic approaches consider not only aquatic habitats of importance but also the landscapes in which these habitats are embedded, which strongly regulate flow, sediment, and nutrient regimes in rivers, lakes, and wetlands. Freshwater KBAs and similar efforts acknowledge the impossibility of securing freshwater species and systems without addressing the lands draining to them. Leal et al.‘s study shows not only high reward for achieving freshwater conservation targets from such an integrated approach but also low risk to achieving paired terrestrial targets.

The good news from Leal et al.‘s study—namely that when we conserve freshwater species and habitats, we receive multiple biodiversity cobenefits—also applies to the delivery of ecosystem services. Two-thirds of today’s human population lives downstream from protected areas, and more than one-quarter of water provisions supplied by the world’s protected areas are exposed to low levels of threat (12). There is a win-win from protecting important source water areas for human communities; an assessment of the likely source catchments of 4000 cities supplying water to up to 1.7 billion people showed that 85% of the area of these catchments overlaps with high biodiversity value freshwater ecoregions (13).

Achieving this wealth of benefits will require strong policy that recognizes the connections between terrestrial and freshwater systems and that treats those systems as equal in importance. And this strong policy must be matched with the resources to enact it. At present, freshwater systems receive a tiny percentage of overall environmental funding; for example, only 3.2% of the environmental funding provided by European foundations, and about 8% provided by North American foundations, goes to freshwater conservation in those regions or elsewhere (14). These funding challenges are likely to get worse, in the face of new economic crises and humanitarian needs in a world shaped by coronavirus disease 2019 and other potential pandemics. There are always trade-offs associated with any prioritization—in spatial planning, policy, and resource allocation—but the study by Leal et al., combined with complementary analyses of the multiple benefits of healthy fresh waters and their watersheds, suggests that those trade-offs may be more acceptable than we think.

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