Preserving genetic diversity — more than meets the eye
So what exactly do we preserve when we target an ecosystem? Let’s evaluate three general scenarios using the currency system:
Imagine three lakes with identical numbers of individuals. Although the number of organisms in each of these communities may be the same, these communities possess different levels of diversity. Now, suppose that you can only save one of these three lakes. Decisions about which one to save may be made on their relative currency value (if you focus on maximizing genetic diversity) or on the other considerations described below.
Saving this ecosystem would maximize the number of individuals of a single species. You may want to preserve this ecosystem if this particular species is a rare one, either a local endemic or a sparsely distributed species. This approach prevents potential loss of genetic variation in an endangered species.
Other factors to consider: A single-species strategy may not be sustainable in the long term, however, and is not the most effective one for preserving biodiversity. Locally endemic species can be saved by protecting a small area, but they are very susceptible to extinction due to over-exploitation and habitat loss. Also, saving sparsely distributed species in the wild is very difficult and expensive because even a small population requires protection of a large area or of smaller areas connected by migration routes.
Another way of assigning priorities would be to select the regions with the greatest number of species. In this case, individuals are from different species that are closely related to one another.
Other factors to consider: Some ecosystems may be important to preserve because they are of scientific interest (or of interest to collectors or tourists). For example, African lakes with many species of closely related cichlids are of particular interest to scientists who study adaptive radiation.
Although the same number of species is represented in this scenario and in the previous scenario, this time we take into account the evolutionary relationships of the species represented in the habitat. This strategy would maximize biodiversity as measured by phylogenetics. Here, species are more distantly related to one another than in the second scenario. As more information becomes available about phylogenetic relationships, policymakers are able to make choices that preserve genetic diversity by prioritizing ecosystems with a broader representation of species and lineages.
Other factors to consider: In addition to being the subject of scientific interest and popular enjoyment, such ecosystems are valuable because they are self-perpetuating. Biologically diverse ecosystems preserve their component species and therefore reduce the need for future conservation efforts targeting individual endangered species.
Currency systems assign numbers to conservation values — and this can be a helpful tool in making comparisons of different ecosystems. However, policymakers must also consider less quantifiable aspects of ecosystem preservation — such as the ecosystem’s potential for future use, its potential for long term preservation, and its value to the local human community.