The
REAP Report --- BIODIVERSITY LOSS?
The
loss of any country's natural bio-diversity is and should be
a concern to everyone. However, it is important that when such
issues are discussed that the threat of such loss and the amount
of such loss be realistically analysed.
Most
early estimates to measure potential biodiversity loss use simple
island models that linked a loss in habitat areas with a loss
of biodiversity. A rule of thumb indicated that loss of 90%
of forest meant a 50% loss of species inhabiting those forest
areas. Thus as rainforests seem to be cut at alarming rates,
estimates of annual species loss ranged anywhere from 20,000
- 100,000. Many people thus expected the number of plant and
animal species to disappear by at least one-half across the
world within a generation.
However,
new data simply does not bear out these earlier predictions.
While the threat of biodiversity loss is real, it has been grossly
exaggerated in many cases. For example, in the eastern United
Sates forests were reduced over two centuries to areas totalling
just less than two percent from their original size. Yet this
resulted in the extinction of only one forest bird. In Puerto
Rico, the primary forest area has been reduced over the past
400 years by 99%, yet only 7 of 60 species of bird have become
extinct. All but 12% of Brazil's Atlantic rainforest was cleared
in the 19th century, leaving only scattered sections of the
original forest. According to the conventional rule-of-thumb,
half of all the animal species living in the Brazilian Atlantic
rainforest should have become extinct and thus disappeared forever.
However, when the World Conservation Union and the Brazilian
Society of Zoology surveyed all 291 known Atlantic forest animals,
none were found to be extinct. These forest animals had adapted
to the changes in their natural environment and thus continued
to survive.
The
same case studies indicate that loss of tropical forests has
also been exaggerated. Many environmental organizations have
claimed that tropical forests were being lost at an annual rate
of up to 4% and would thus be completely depleted within twenty-five
years. However, these forest losses appear to have been grossly
over-estimated. The latest United Nation figures indicate such
losses to actually be less than one-half of one percent. And
with current reforestation efforts, such as that being practised
on Mangaia, forest areas previously lost will actually be reclaimed
and thus increase for the future benefit of the island and its
people.
Most
species in our natural biodiversity have proven more resilient
to human encroachment than expected. Thus, while the threat
of biodiversity loss appears in most cases to have been exaggerated,
it is still real. We must take proper precautions at all times
to preserve and protect the Cook Islands unique biodiversity.
Cook
Island News, 24 February 2003
