than an inventory of species, as is the case to
certain extent when one considers that heralds of
the biodiversity crisis originally paid most attention
to the loss of species in deforested areas. Most
ecologists now recognise that biodiversity defines a
working system of interactions between species rather
than just a list of species. In fact, the concept of
biodiversity is very complex and embraces many
different elements, often complementary but also very
distinct. According to Noss (1990), biodiversity has
three principal components:
- Composition: different genes, species, biological
and physiological functions, habitats, communities and
landscapes are the basic units of biodiversity;
- Structure: the patterns of organisation of
biodiversity dictate how its components interact across
the various boundaries separating cells, organisms,
populations, and habitats;
- Function, e.g.: transfer of genes within species
and speciation processes; behaviour of organisms and
ecological interactions between and among different
populations; role of biodiversity in the productivity
and resilience of systems.
Currently, the functional relationships between
species in ecosystems are still poorly understood, and
one of the central questions dealing with biodiversity
is: would it really matter if our living systems were
they influence or perform” (Huntley, 1989). But it
-also includes the variety of life-history styles, and
the number of interactions between organisms and the
environment (Bruton, 1990).
The concept of biodiversity has been used in
different ways. For a few people it is no more