ANYONE GIVE A GOOD REASON FOR CONSERVING BIODIVERSITY?
by Whit Gibbons
February 24, 2002
Last week I said I would answer one of the most basic environmental
questions: why should we try to preserve natural biodiversity?
Conflicts related to species preservation and protection of
biodiversity continue to arise among different groups and individuals
throughout the world. The ubiquity and the abundance of such
clashes suggest that no universally accepted statement exists
about the importance of preserving biodiversity, in part because
issues outside the realm of ecology are involved. Economics
and personal agendas, plus different interpretations of the
same environmental information, guarantee that such disputes
will never disappear.
Nonetheless, those who appreciate the natural world should continue
to maintain the need for protecting natural biodiversity. Some
answers given by environmentalists two decades ago are still
worth educating people about. For example, science has limited
knowledge of the biochemical and genetic traits of most known
organisms and knows nothing of species still undiscovered. Therefore,
environmental destruction could eliminate a species possessing
a medical marvel, food product, or other valuable human resource.
For those needing evidence, consider the rosy periwinkle of
Madagascar, a tiny plant discovered to produce a chemical used
to combat childhood leukemia. Or, the chemicals produced on
the skin of tropical poison dart frogs, which offer promise
as a painkiller many times more powerful than morphine.
Various other reasons have been advanced for conserving other
species. Ethical, aesthetic, and religious grounds are difficult
to argue against because they are personal positions that individuals
take on the issue. On the other hand, convincing someone who
does not have a similar ethical code or the same appreciation
of diverse habitats or a sense of stewardship may be difficult
or impossible. Arguments based on these issues often end in
a stalemate, with the environment and biodiversity being winners
or losers depending on who has the most clout economically,
politically, or with the general public.
justifications for maintaining natural biodiversity include
environmental stability and productivity. A study published
in Nature by University of Maryland scientists B. J. Cardinale,
M. A. Palmer, and S. L. Collins lends experimental support to
this argument. Unraveling all plant and animal interactions
in an ecosystem is too complex and difficult for any study,
so the investigators examined how a single group of insects,
caddisflies, were affected by a loss in biodiversity.
are flying insects whose larvae live in streams, attaching to
a rock underwater. The caddisfly larva's feeding mechanism is
to build a little net to capture tiny particles of organic matter.
In a sense, they lasso their food as it passes by them in the
water. The details of the study are complex, but the conclusion
seems irrefutable--as the number of different caddisfly species
present in a stream increased, the more productive and efficient
each species became. Extending this finding to the broader issue
of overall biodiversity, reducing the number of species in a
system reduces the effectiveness of the remaining species.
reading a recent article in Science, anyone might wonder why
debate continues about whether environmental health can be diminished
by a loss of biodiversity. According to A. Hector of Imperial
College in England and R. Hooper of the National Institute of
Environmental Studies in Japan, the first ecological experiment,
conducted by botanists in the early 1800s, was designed to test
the effects on cultivation of mixing different species of grasses.
Charles Darwin referred to the early study in "The Origin
of Species," stating that "it has been experimentally
proved [that] a greater weight of dry herbage" can be harvested
when several species of grasses are grown together than when
one species is grown alone. In essence, Darwin came to the same
conclusions as those reported after the recent caddisfly experiment.
Although various reasons can be given for why we should try
to preserve natural biodiversity, none is a clincher that will
stop environmental destruction and the continued loss of species
and their populations. Perhaps the best answer is another question:
what right does someone have to eliminate native species and
destroy natural habitats when someone else wants them to endure?
you have an environmental question or comment, email