The ecologist Ruth Patrick defined biodiversity as "the presence of a large number of species of animals and plants." Granted, this definition can be refined and there are books full of discussion about the how, and why, and where of biodiversity. But that succinct statement defines what we mean by the term biodiversity.
The biodiversity of our world is awe inspiring. I've often wondered if we were to be visited by ecotourists from another planet, would our biodiversity be as astounding to them as it is to some of us?
Unfortunately our world is in the midst of a biodiversity crisis. Large numbers of unique, irreplaceable species are becoming extinct and even larger numbers are becoming endangered or threatened. And this is happening before we have even become acquainted with most of those species that share planet Earth with us.
Right now about 1.5 million different species of living things have been described and given names. Most middle of the road estimates by scientists suggest there exist, right now, about 12.5 million different species. We have accomplished only the most preliminary step - giving a name - to only one out of eight of all those species.
The writer David Quammen, in his book The Song of the Dodo: Island Biogeography in an Age of Extinction, relates a metaphor that nicely illustrates the importance of biodiversity. He asks us to imagine that we have a fine Persian carpet, say 12 by 18 feet; a hand-knotted carpet with hand dyed yarns, a thing of great beauty and craft and very precious. Now let us imagine carefully cutting this carpet apart into small rectangles - say 2 by 3 feet. When we're done do we have a Persian carpet anymore? No, we have 36 rather elegant doormats. And it is the same with ecosystems; the remnants left after we have disturbed natural systems and reduced the biodiversity are less significant that the original system in a qualitative way. And, as with the Persian carpet, we can never completely restore the ecosystem any more than we can weave the pieces of carpet back together.
There are many different reasons why we should try to preserve this biodiversity of plant and animal species. They range all the way from aesthetic and ethical reasons down to very practical considerations about their use as potential sources of pharmaceutical chemicals, agricultural genetic material, as their appeal for ecotourism.
For whatever reason you wish to preserve biodiversity, there is really only one effective way to go about it: preserve (or restore) the habitats where the species live. You, personally, may be interested in preserving a certain group of animals or plants or even a certain species you feel is emblematic of diversity (a signature species, such as the Giant Panda or the Landlocked Salmon). But to be successful you have to provide the habitat where the species can live and reproduce and maintain a population. Attempting to preserve a species while allowing the habitat that supports it to be destroyed is doomed to failure.
On a world-wide basis massive amounts of habitat are being destroyed as we try to provide food, living space, and goods to our ever increasing numbers of human beings. Even here in our area we see the progressive loss of wild habitat as the area becomes less an area of farms and woodlands and more a rural bedroom community where the land is chopped up into small residential holdings.
Species diversity depends partly on the presence of natural habitats. The greater the number of physical habitats you have in an area, the more species you will be likely to have. So we need to preserve habitats to preserve the biodiversity of species of plants and animals. And these habitats should be in as many different types of physical situations as possible. Species diversity also depends on the size and connectivity of the habitat parcels. Larger blocks of land support relatively larger numbers of species than do smaller ones. A parcel of woodland might be of a suitable type, for example, for our black bear, but unless it is a fairly large parcel it won't be able to support a bear population. So when we preserve habitats we also need to keep them connected together in areas as large as possible. For those of us who live in the Boquet River watershed the need to preserve the connectivity of habitat parcels is an important task.
To preserve habitats we need to protect them from development that reduces their species diversity. In some areas this will involve protecting natural areas from change. In our area, where little natural habitat remains, it also means that we need to protect areas where habitat can revert back toward its original state.
For protection to last for the lengths of time that will make a real difference it has to involve some kind of legal protection for the land containing the habitat. The good will of an individual is critical, but if the person's legacy dies with them it has all been for nothing.
One way the land can be protected is for it to be purchased by or deeded to some authority or organization that can and will protect it for future generations. Another way can be the negotiation of some type of stewardship arrangement where the owner retains title to the land but agrees to write into the deed certain restrictions about its future development.
Both of these involve a sacrifice. It may come from the individual landowner who donates or sells at a reduced price to make the preservation of the land possible. Or it may come with the acceptance of the restrictions entailed in a stewardship agreement. Or it may come from the local taxpayers who, even if they don't own the land in question, accept possible tax increases because certain land in a town is no longer open for development.
|click for technical information about measuring biodiversity|