Why are freshwater species in trouble? Bad p.r., for one

Hippo

Hippo yawning in Botswana. (© Rod Mast)

Freshwater species have a publicity problem: Unlike iconic tigers or sharks, no one is paying attention to the the Baikal seals and hippos of the world.

That’s a mistake.

Freshwater megafauna — large animals, in other words — are disappearing at a faster rate than species that live on land or in our oceans, yet their their loss receives less attention and attracts less funding for prevention. The bigger issue? Declining biodiversity in the rivers, streams and lakes these freshwater species call home spells trouble not just for animals, but for everyone who relies on fresh, clean water.

I co-authored a new paper, published this week in the international journal BioScience, that aims to show people how we can protect important freshwater ecosystems by turning up the “wow” factor and shining the spotlight on large, charismatic freshwater species including turtles, river dolphins and sturgeons.

Sounding the alarm on an invisible crisis

First, the doom and gloom: Compared with other biodiversity crises, freshwater species are doing much worse. According to the IUCN Red List of Threatened Species, about 28 percent of assessed freshwater species are heading for extinction. As shown by the 2016 Living Planet Index, they’re declining at a faster rate (an 81 percent decline between 1970 and 2012), than for marine (36 percent) and terrestrial (38 percent) species. Yet the problem of declining freshwater biodiversity isn’t getting the attention and funding it needs. Our paper suggests we can raise awareness and encourage conservation action for important freshwater ecosystems by highlighting the charismatic species that live there.

Freshwater species loss is often hidden in murky, turbid rivers where people can’t easily see or even film wildlife, rendering this problem largely invisible. People only seem to notice something is wrong when they don’t have enough water to drink, when the water they have is polluted, or when they lose power because there’s not enough water flowing through a dam. We need people to realize that biodiversity is often a good indicator of the water issues that people face — by looking after freshwater species, we’re looking after ourselves. If we can keep these ecosystems healthy, it helps us to ensure our own health.

To get attention, focus on big animals

The paper suggests that the way to draw attention to these issues is to play up charismatic species. People care about megafauna such as lions and elephants, and we wanted to see if we could find similar large, exciting species in freshwater areas. While freshwater species aren’t warm and fuzzy, many are impressive: the Mekong River’s giant catfish can weigh as much as 650 pounds and live to be 60 years old! If we can promote these big freshwater species and move people to advocate for protecting them, we’ll end up protecting freshwater habitats in the process.

We used 30 kilograms (66 pounds) as the metric for defining a large species, and then selected a subset of those species that we thought were well-known and that can serve as “ambassadors” for the importance of freshwater conservation. Our study showed that many of these species are already seriously imperiled: 58 percent of the 132 species we selected are classified as threatened. Species of sturgeons — which include many large and iconic species — are more critically endangered than any other group of species.

Size isn’t the only notable characteristic for large freshwater species: They can have unique features and long lives. For example, the New Zealand longfin eel can live to 100 years old, and the Chinese paddlefish has a snout that averages almost five feet long. Paddlefishes, related to sturgeon, are also threatened: IUCN lists the American paddlefish as vulnerable, and the Chinese paddlefish as critically endangered — possibly even extinct. In the same way that jaguars are flagships for conservation in South America or pandas are flagships for conservation in China, river dolphins, sturgeons, hippos and crocodiles are freshwater species that we can attach our conservation messages to as strong symbols of freshwater habitat.

Characteristic freshwater megafauna occur in areas of high species diversity, existing in areas that match 93 percent of all mapped overall freshwater biodiversity. Eighty-three percent of the world’s threatened freshwater species occur in the same range as these megafauna. By saving these eye-catching, large freshwater species from threats such as overexploitation, habitat changes and pollution, we can conserve many other species that also depend on these habitats. At the same time, we’ll ensure the safety and security of all the resources freshwater habitats provide: water purification, flood regulation and carbon sequestration.

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Take a ‘whole-watershed’ approach to conservation

Nearly two-thirds of the global human population lives downstream from protected areas and uses the fresh water that flows from them. Because large freshwater species tend to migrate through large rivers, they can help raise awareness of the need to think about water holistically. Upstream pollution affects downstream water quality, and having a protected area at the end of a river may not be as effective if we’re not also protecting habitats upstream. About 84 percent of the overall range freshwater megafauna falls outside of protected areas, so we have an urgent challenge to protect these regions, for both freshwater species and for human populations that rely on freshwater flows and resources.

Now, conservation biologists are thinking more about how to achieve conservation in terms of whole watersheds, which doesn’t necessarily mean protecting an entire watershed, but instead developing a sustainable system. To be effective, we have to protect freshwater in an integrated way across watersheds while taking into account the multiple needs of each area, such as where and how people use water, where threatened species live and how these species move through different water systems. This could mean protecting three or four connected sites in a watershed, or tracking megafauna migrations to find out where we should focus our efforts. We have an excellent model to work from, developed back in 2007 by Robin Abell and colleagues, who now leads Conservation International’s Freshwater Health Index.

We need to use every opportunity to build public interest and support for government policy that advances conservation. With freshwater megafauna, we have a great chance to communicate why freshwater ecosystems are so important, and what we can do to increase freshwater biodiversity. Biologist Zeb Hogan, one of my colleagues from IUCN’s Freshwater Fish Specialist Group, is doing just that: Watch his video here.

Ian Harrison is the freshwater specialist for Conservation International’s Moore Center for Science and co-chair for the IUCN Species Survival Commission’s Freshwater Conservation Subcommittee.

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