BIODIVERSITY
The concept of biodiversity has provoked considerable debate and misunderstanding
among the general public, decision-makers, and even the scientific
community. Much has been published on the subject since its first
appearance at the National Forum on BioDiversity in September, 1986,
the proceedings of which became the best-seller BioDiversity. But
what is biodiversity, what threatens it, why is it important, and
what are ecologists doing to better understand it?
What is Biodiversity?
Short for biological diversity, biodiversity includes all organisms,
species, and populations; the genetic variation among these; and all
their complex assemblages of communities and ecosystems. It also refers
to the interrelatedness of genes, species, and ecosystems and their
interactions with the environment. Usually three levels of biodiversity
are discussed-genetic, species, and ecosystem diversity.
Genetic
diversity is all the different genes contained in all individual
plants, animals, fungi, and microorganisms. It occurs within a species
as well as between species.
Species
diversity is all the differences within and between populations
of species, as well as between different species.
Ecosystem
diversity is all the different habitats, biological communities,
and ecological processes, as well as variation within individual ecosystems.
What are the Threats to Biodiversity?
The loss of biodiversity is a significant issue for scientists and
policy-makers and the topic is finding its way into living rooms and
classrooms. Species are becoming extinct at the fastest rate known
in geological history and most of these extinctions have been tied
to human activity.
Habitat
loss and destruction, usually as a direct result of human
activity and population growth, is a major force in the loss of species,
populations, and ecosystems.
Alterations
in ecosystem composition, such as the loss or decline of
a species, can lead to a loss of biodiversity. For example, efforts
to eliminate coyotes in the canyons of southern California are linked
to decreases in song bird populations in the area. As coyote populations
were reduced, the populations of their prey, primarily raccoons, increased.
Since raccoons eat bird eggs, fewer coyotes led to more raccoons eating
more eggs, resulting in fewer song birds.
The
introduction of exotic (non-native) species can disrupt
entire ecosystems and impact populations of native plants or animals.
These invaders can adversely affect native species by eating them,
infecting them, competing with them, or mating with them.
The
over-exploitation (over-hunting, over-fishing, or
over-collecting) of a species or population can lead to its demise.
Human-generated
pollution and contamination can affect all levels
of biodiversity.
Global
climate change can alter environmental conditions. Species
and populations may be lost if they are unable to adapt to new conditions
or relocate.
Why is Biodiversity
Important?
The diversity of life enriches the quality of our lives in ways that
are not easy to quantify. Biodiversity is intrinsically valuable and
is important for our emotional, psychological, and spiritual well-being.
Some consider that it is an important human responsibility to be stewards
for the rest of the world's living organisms.
Diversity breeds diversity. Having a diverse array of living organisms
allows other organisms to take advantage of the resources provided.
For example, trees provide habitat and nutrients for birds, insects,
other plants and animals, fungi, and microbes.
Humans have always depended on the Earth's biodiversity for food,
shelter, and health. Biological resources that provide goods for human
use include:
food-species
that are hunted, fished, and gathered, as well as those cultivated
for agriculture, forestry, and aquaculture;
shelter
and warmth-timber and other forest products and fibers such
as wool and cotton;
medicines-both
traditional medicines and those synthesized from biological resources
and processes.
Biodiversity also supplies indirect services to humans which are often
taken for granted. These include drinkable water, clean air, and fertile
soils. The loss of populations, species, or groups of species from
an ecosystem can upset its normal function and disrupt these ecological
services. Recent declines in honeybee populations may result in a
loss of pollination services for fruit crops and flowers
Biodiversity provides medical models for research into solving human
health problems. For example, researchers are looking at how seals,
whales, and penguins use oxygen during deep-water dives for clues
to treat people who suffer strokes, shock, and lung disease.
The Earth's biodiversity contributes to the productivity of natural
and agricultural systems. Insects, bats, birds, and other animals
serve as pollinators. Parasites and predators can act as natural pest
controls. Various organisms are responsible for recycling organic
materials and maintaining the productivity of soil.
Genetic diversity is also important in terms of evolution. The loss
of individuals, populations, and species decreases the variety of
genes-the material needed for species and populations to adapt to
changing conditions or for new species to evolve.
What are Ecologists Doing to Better Understand Biodiversity?
Knowledge of biodiversity has increased in the last ten years, as
has the realization that something must be done to counteract the
loss of species, populations, and ecosystems. There is still much
to be learned about biodiversity and its relationship to the functioning
of our world, so scientific research and debate continues. And results
are being applied to efforts to conserve biodiversity now.
Ecologists conduct research to better understand biodiversity, quantify
its loss, and develop strategies for conserving and using it. Much
is still unknown as to what species exist, where they occur, and the
relationships between them. By inventorying and monitoring biodiversity,
ecologists study species abundance, functions, interactions, and importance
to maintaining or enhancing the quality of human life. Questions to
which ecologists are seeking answers include:
How
fast and in what locations is biodiversity being lost? And why?
What
are the secondary consequences of those losses?
What
management interventions will prove most effective in preventing the
loss of biodiversity?
Ecologists study the natural changes in biodiversity at the genetic,
species, and ecosystem levels. This allows them to evaluate human
impact by comparing natural processes to human-induced changes. Recent
work suggests that the loss of populations are of greater consequence
than the loss of species and are occurring at a faster rate.
Ecologists also play a prominent role in researching the conservation,
restoration, and use of biodiversity and related ecosystem processes.
Some ecologists investigate the effects of different land uses and
management practices. Restoration ecologists are developing rationale
and methodologies for rehabilitating or restoring damaged habitats
and for reintroducing native species. Another important area of ecological
research is understanding the implications of global climate change
for biodiversity conservation.
A new challenge for ecologists is determining the relationship between
biodiversity and ecosystem functioning. This issue was identified
as one of the top research trends for 1998 by Science magazine. Some
of the questions ecologists are exploring include:
What
are the ecological consequences of the loss of species, populations,
or groups of species which perform a common function?
Are
the services that healthy ecosystems provide humans diminished with
a loss of biodiversity?
What
effects do biodiversity and biogeochemical processes (such as nutrient
cycling) have on each other?
Ecologists are working with other biological scientists, as well as
social scientists, policy-makers, and economists. Such an interdisciplinary
approach is necessary to develop strategies to conserve Earth's biodiversity.
Terms
Biodiversity: The range of variation found among
microorganisms, plants, fungi, and animals. Also the richness of species
of living organisms.
Community: Populations of organisms of different
species that interact with one another.
Ecosystem: Any geographic area with all of the living
organisms present and the nonliving parts of their physical environment.
Involves the movement and storage of energy and matter through living
things and activities.
