Imagine you’re a little girl—let’s call you Brooke—and you and your two siblings are sitting in the waiting room of a pediatrician’s office. The pediatrician pokes her head through the door and your older sibling, Marin, stands up and then waves as she follows the doctor. When she’s done, your twin brother, Forrest, leaves your side and walks into the office. A few minutes later, Forrest and the pediatrician return. You stand, bravely, ready to walk in the room.
“I don’t need to see you,” says the doctor casually, “I’ve already looked at your brother, so I know all I need to know about you and what medicines you should get.”
While somewhat relieved to avoid any shots today, your face flushes and your heart sinks as you realize that, once again, you’re being overshadowed by your siblings—and even worse, lumped in with your twin, like you’re not your own person, just an extension of him. Sure, he’s a bit more outgoing—he just seems to occupy a lot more space than you do in any room—and people also find him more relatable because he’s so grounded and down to earth. Meanwhile, people always say that you’re mercurial and elusive, hidden beneath an opaque shell that prevents them from seeing what’s beneath the surface.
“It’s not fair,” you whisper, thinking, “I may be much smaller than Marin, but my collection of stuffed animals is BIGGER than hers! And Forrest may have a higher profile and get all the credit, but I do as much and maybe more of our chores around the house!!”
By now, you have probably realized that this isn’t a story about a brave, but often overlooked girl but, rather, a brave, but often overlooked, ecosystem type: freshwater systems, including lakes, rivers and wetlands. (And yes, in my not-too-subtle extended metaphor, Marin represents oceans and Forrest stands in for terrestrial ecosystems).
Freshwater ecosystems are often overlooked, in terms of protection strategies and global conservation targets, or simply lumped in with terrestrial habitats. In other words, the conservation treatments prescribed for land are often simply assumed to work for freshwater systems.
For example, protected areas, such as national parks, have traditionally been designed and managed primarily to conserve terrestrial resources (e.g., mountains, forests, iconic wildlife), with the expectation that freshwater systems and species will largely come along for the ride. In reality, they are more likely to miss the bus, as demonstrated by a recent paper in Science.
The researchers found that if conservation programs prioritize terrestrial species, they will capture only 22% of the freshwater benefits that could be achieved through freshwater-focused conservation planning. But if terrestrial and freshwater planning occur together—and try to achieve balanced conservation—then freshwater benefits could increase sixfold, with only a 1% decline in terrestrial benefits.
In other words, prescribing medicine for Brooke based on a diagnosis of Forrest does not work very well but, happily, spending more time diagnosing and treating Brooke will not diminish the health outcomes for Forrest.
Why are freshwater systems so often overlooked? Well, Brooke’s mercurial personality, hidden beneath an opaque shell, is not just metaphorical. Freshwater species, literally beneath the surface, are far harder to see than their terrestrial counterparts and this has contributed to their relative obscurity.
And, in a relative sense, freshwater systems are a tiny portion of the planet, with lakes and rivers representing less than 2% of the planet’s surface. The volume of water in the oceans is more than 10,000 times greater than the volume of water in lakes and rivers.
But freshwater systems punch way above their weight. From that relatively small proportion of surface area and volume, freshwater habitats support more species of fish than do the oceans (18,075 species, which is 51% of all fish species on Earth), as reported in “Forgotten Fishes.”
Freshwater fisheries, at 12 million tons/year, represent approximately 13% of the total global harvest of fish, enough to feed nearly 200 million people. This share of the global catch is already fairly impressive—particularly given how much larger the oceans are—but a significant proportion of the harvest from lakes and rivers goes unreported because it comes from small, dispersed fisheries, outside of formal markets. Because of this, experts believe the harvest from freshwater systems could be 65% higher than what is officially reported.
Fish in a market in the Mekong Delta, Vietnam. Freshwater fisheries, at 12 million tons/year, … [+]
JEFF OPPERMAN
Beyond fish, freshwater systems provide a range of services and benefits to people that again, are dramatically greater than their relative size. In a seminal review of the value of the world’s ecosystem services, Costanza and colleagues estimated that floodplains were the second ranked ecosystem type, behind only estuaries, in terms of their value to society, per unit area (and note that estuaries are strongly influenced by the rivers that flow into them). Despite representing less than 2% of Earth’s land surface area, rivers and floodplains provided approximately 25% of all ‘‘terrestrial’’ (i.e., non-marine) ecosystem service benefits, with flood-risk reduction the most valuable among the services.
Meanwhile, despite these values, freshwater systems have faced greater losses than have the other ecosystem types. Wetlands have declined by 70% in the past century and only 1/3 of the earth’s long rivers remain free flowing. Largely because of these losses of habitat, populations of freshwater vertebrates have declined at a rate twice as fast as those in oceans or on land.
So, there you have it. Our brave Brooke has a bigger collection of animals than Marin, does her share, or more, of the chores around the house, and is in clear need of distinct global goals and tailored prescriptions—such as the Emergency Recovery Plan for freshwater biodiversity proposed last year by WWF and a number of academic and conservation experts. Time to start making sure that Brooke gets as much attention as her siblings!
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As the siblings leave the doctors’ office, Forrest gets a call and says, “That was Celeste. She needs me to come help her put a bunch of stuff into some kind of long-term storage. It sounded urgent. Anyway, I’m off.”