Wednesday, November 30, 2011
An Artificial Wetland
Bioloigist's tend to be purists. Many of us aren't satisfied to know that what we have today is the best that we have. We long for the days when American bison roamed the prairie in herds that began moving west at sunrise and were still moving past the same point at sunset. We loathe our ancestors who so foolishly killed Passenger Pigeons that today there are none. We fantasize about seeing the marshes of New Jersey so filled with Brant that the sun was blotted out by their many wings. We still think of the days when Eskimo Curlew were so abundant that shotgun barrels melted from all the shots and the curlews just kept coming. We long for the days that once were while forgetting to enjoy the days that we still have.
Wetlands are a fine example. At the time of European settlement there were more than 5 million wetlands on the surface of the land in North Dakota. In those days early explorers told stories of of waterfowl being in such high densities that the sun was blocked out by the sheer number of birds moving by a point. Today there are fewer than 2 million acres of wetlands remaining in that state and stories of blackened skies are only available to us in history books. Those days no longer exist even though many of us, myself included, wish that they still would.
Florida has the distinction of having, at one point, the greatest number of wetlands of any of the fifty states. Historically there were more than 12 million acres of wetlands in this state. My mind fairly boggles trying to fathom what wild Florida looked like in the days before drag lines and endless condo developments.
Today there are maybe 8 million acres of wetlands remaining in the state making it the wettest state in the lower 48 states. However if you drive around Florida very much you are quickly confronted with the reality that many of our wetlands are artificial - the natural ones are largely gone and have been replaced by things that developers created to mitigate the loss of the real wetlands that we all once knew. Wetland ecologists classify these wetlands as PUB-X - meaning a Palustrine wetland (fresh water) with an unconsolidated bottom (mud) that has been excavated. My guess is that the bulk of the wetlands on Florida's landscape today are PUBx. That really wasn't the original plan.
I began my career as a wildlife biologist in 1976 studying ducks and buying wetlands in western Wisconsin. From that I went to evaluating wetlands for Federal acquisition in six midwestern states. Then for 12 years I worked on wetlands issues in North Dakota and Nebraska and finally ended my career in Washington DC where I managed a wetlands mapping program. To say that wetlands have been a part of my life is an understatement.
As I have traveled around Florida in recent years it has been nearly impossible to not notice that there are a lot more PUB-x wetlands on the landscape than there are semipermanenty wetlands or temporary wetlands and certainly not estuarine emergent wetlands. Just like so much else of our society we humans have transformed what was from a natural state to a more "acceptable" altered state. Natural lands and natural wetlands are a novelty now not the norm. Drive around Orange or Seminole Counties (suburban Orlando) and try to find something that was there one hundred years ago - just dont tear your hair out when you can't.
For the longest time I've viewed artificial wetlands as a blight on the landscape. They are not natural - they even have an X in their name to indicate they are manmade - but still they exist. Research project after research project has shown unequivocally that artificial wetlands do not and cannot mimic the same values and functions that natural wetlands possess. However what reasonable person would expect them to?
This morning while on a grueling 9 mile walk (well grueling when you are 60 years old) I passed by a familiar artificial wetland that I've been passing each day along my route. Each day I pass this wetland (shown above) I notice that its shore is largely devoid of emergent vegetation (like you would expect in a "real" wetland) and the number of birds using its habitats are not what you would expect to see on the edge of a real wetland. Still they are there. There is vegetation that looks like the sedges and grasses you would expect on the verge of a natural wetland in Okeechobee County. And there are birds on the wetland like White Ibis and Great Blue Heron and Little Blue Heron and this morning they were joined by at least two pairs of Hooded Mergansers freshly arrived from somewhere further north. There weren't huge numbers of birds but there were birds. It was much more aesthetically pleasing to see something with feathers on that wetland than to see it devoid of any bird life at all.
As I took in the scene and tried to make some sense out of what I witnessed a change came over me. I will until the day I die detest the destruction of natural wetlands for whatever reason. They have been there for millions of years before humans came on the scene. However after witnessing birds using artificial wetlands today I had an epiphany. What would happen if there were no artificial wetlands at all? Where would the Little Blue Hersons go then? Its all well and good to get bent out of shape and posture and argue and blow off steam but in the end if there are no artificial wetlands everyone, especially the birds, lose.
Each fall migration more than 1 million shorebirds of many species migrate over and past the island of Barbados in the southern Caribbean/western Atlantic. When the birds arrive on the island most of them are severely emaciated and are literally on their last leg. Luckily for them shorebird hunters maintain 14 artificial wetlands on the island that they use to attract shorebirds for hunting.
When I first visited Barbados in 1991 I was hell bent on making arrangements with the local government with the help of the US Ambassador to the Lesser Antilles to put an end to shorebird shooting. After all the shorebird shooters were killing 30,000 birds for sport and I considered that a huge waste.
However one day at the Mangrove shooting swamp something dawned on me. If I was able to pull off what I wanted to pull off - the cessation of shorebird hunting on Barbados - there would be no incentive for the 14 individuals who maintain those artificial wetlands to attact shorebirds to continue doing so. We would certainly "save" those 30,000 shorebirds from death by gunshot on Barbados but in the process there would be no incentive to maintain the wetlands that support habitat for 1 million birds who use the island habitat on their way to South America. The last time I checked, 30,000 was 3 percent of 1 million. In any normal animal population at least 50 percent of young birds born that year will not make it to their first birthday. In other words 500,000 of those birds were going to die whether the shorebird shooters of Barbados got them or not.
There was only one logical solution that could be reached. It was wiser in the long run for the shorbird shooters to maintain wetlands for that million birds than it was to stop the shooting to momentarily "save" 30,000 birds most of which will die in a few months anyway.
The same analogy holds true for the artificial wetlands of Florida. I don't like seeing so many of them on the land scape but the alternative is the latest strip mall or yet another housing development or the latest interchange from Interstate 75 or a new Holiday Inn on Fruitville Road. Which gives birds more of a fighting chance?
This morning I realized that despite my dislike of artificial wetlands they are a much more acceptable and aesthetically pleasing alternative than the alternative of another strip mall blighting the landscape.
Its funny what you see when you look beyond the trees of a forest and see what lives inside.