Wetlands 1: The Real Estate Crisis in Protected Areas

A basic question for some readers may be, Well, what’s a wetland, and why are they important? I think most wetlands biologists would agree that wetlands are a type of ecosystem where the soils are flooded often enough to have developed anaerobic (non-oxygen needing) processes and for the species living there to have some adaptations (in a Darwinian sense) to flooding or flood cycling. Wetlands are extremely important worldwide, for lots of reasons. They’re important for people as the nursery for many kinds of fisheries, as water sources for drinking and agriculture, and as water purification systems. They are extremely diverse in subtypes. If we include high-latitude regions, by area wetlands occupy more of the earth’s surface than rivers and large lakes. There are a lot of wetlands globally, though the U.S. is typical here for losing about 50 percent of our wetlands since European and African settlement began ~1500 and for not doing very much to protect the wetlands that are left. Wetlands are the least-protected type of freshwater ecosystem, worldwide, though they are also the most common type of freshwater protected area.

But back to our story.

As I mentioned above, wetlands as a group are extremely climate sensitive. That’s because they’re shallow, and most of the actual water in wetlands — that wetness bit — is from precipitation that either falls directly into the wetland itself or into its catchment, the surrounding terrestrial zone that drains into the wetland. There may be some current in a wetland, draining further into a river or the ocean, for instance, but often the major outflow is evaporation (or evapotranspiration — ET— if we want to include the water that all of the plants that live in the wetland are able to send into the atmosphere too). Thus, wetlands tend to exist in a delicate balance: precipitation vs. evapotranspiration, inflows vs. outflows, up vs. down.

From a climate perspective, ET and precip have hair triggers. Even small shifts in climate tend to create big swings in “normal” rainfall rates, and ET is a climate variable that particularly reflects a whole range of other variables, like air temperature and humidity, not to mention the plants that are living in a given place. This contrasts with most lakes, for instance, which tend to have a lot of water and to be tied strongly into groundwater sources. Likewise, lakes have a big thermal mass — they don’t heat up or cool down easily. So they’re less likely to evaporate away during a drought. And they can store a lot water from a flood. Rivers have even longer lifetimes. Some large rivers have been around for millions of years. The big basins that created rivers in the first place may only go away as a result of significant geological events. And rivers move: imagine pulling snowmelt from high mountains to groundwater across the central part of a basin to the estuary and ocean. I’m not saying that rivers and lakes are climate-insensitive. But they have thicker skins than wetlands.

What this means is that when we back begin to look at wetlands over climate-relevant timescales like centuries or millennia, we see that they (a) tend to jump around the landscape, and (b) change in their qualities very rapidly. The Pantanal in South America is the largest wetland in the world. Currently, it’s in a large, wet phase. But that’s pretty new, dating back only about 1500 years. The four or five millennia before that, the Pantanal was in a smaller, drier phase. Fires were an even more important part of its dynamic than now. The vegetation and animals were quite different too — more akin to the cerrado savannah you see to the north and east of the Pantanal now. Smaller wetlands change even more dynamically. And pretty much every other wetland on the planet is smaller than the Pantanal.

This leads us back to protected areas, to the PAs, which have only been around in their modern incarnation in any form as actively and “scientifically” managed for about 120 years. That’s been a period of relative climate stability. I don’t know when the first wetland PA was created, but they came later—after the forests and rivers, but before the coral reefs and coastlines. One of the core founding ideas behind PAs was to “fence out” change, the kind of change humans typically bring to an area. Cutting trees. Overharvesting native species. Introducing industrial or household pollution. The idea of keeping out change is central to PAs. For the most part, it’s a great idea and has been reasonably effective in preserving (i.e., minimizing change) a lot of pieces of real estate worldwide.

But change isn’t always easy to fence out of an area, especially if the change we’re talking about is climate-driven change. The contradiction that is particularly true for wetlands is that wetlands balance delicately between precip and ET in a place, and when that balance changes, the wetlands respond, often very quickly. And here’s the rub: you can’t fence out climate change. Not with wetlands. (And probably not with anything else either.)

So we’ve made these wetlands PAs, but they exist in a climatically dynamic manner that may not be compatible with (a) the boundaries of the PA, or (b) the way that we manage on a daily or monthly basis the species within the PA. This is what I call the real estate problem with PAs.

The problem has two big implications. One is hydrological: Imagine a wetland PA wants to expand seasonally form its assigned borders as a result of more-intense precip events and more-frequent flash floods (both common climate impacts), then we tend to react badly. We call that dangerous flooding, because the wetland has intruded on our crops or houses. And we want to build dykes to fence the wetland back into its borders, as we’ve defined them. And this leads to the second implication, which is ideological. Let’s call it the wetland that’s in our head, which is different from the wetland that is on the ground. Our head-wetland is fixed and non-dynamic. We “can” fence it in place and in assigned boundaries because that’s where we’re used to seeing it. But of course the wetland isn’t fixed. It changes and moves, and it always has: daily, seasonally, and even (now) climatically. It doesn’t pay attention to property lines or ownership disputes. It’s inconvenient and noncompliant.

We can’t do that much about the hydrological implications, especially if the trends we’re seeing in climate are just the opening chords in a long symphony of human-driven climate change. In our example, the dykes will have to get higher, the threat of disaster more threatening. Much better is to change the ideological implications. Get rid of the fixed model. Adjust ourselves and our image. That’s not easy. It means that instead of seeing a shifting wetland as noncompliant, we’re actually seeing ourselves as noncompliant, fighting changes that are just beginning and likely to strengthen.

Moreover, we have to think about the daily and monthly management practices in these wetlands. Are the species we see in these wetlands forever tied to particular places? Will the great cypress swamps I grew up in always look the same? In all likelihood, no, not even for the rest of my lifetime. We are experiencing geological-scale change over a non-geological timeperiod — a single human lifetime. Species are already responding to the change we don’t want to see or can’t observe. Birds nest and migrate at different times. Insects become adults at different seasons, or have three generations annually instead of two. They can see the wetlands change, and they do not have the ideological barrier we possess.

We need a new vision of PAs, at least for wetlands. And a new vision of ourselves as the caretakers of wetlands.

Tags: climate adaptation, wetlands, policy, climate refugia, ramsar