Biology Reference
In-Depth Information
in hunted forests as compared with protected forests where primates and large fruit-eating
birds still thrive.
The loss of the big, rare tropical trees from logging would also have a dramatic ecological
effect. By combining Greg Asner's laserscanning data on the carbon density of the rain forest
with the information Sue, George, and Gabriela had gathered, we have recently learned even
more about how the fates of jaguars, monkeys, macaws, and peccaries and the future of trop-
ical forests are closely linked. The tree species that hold the most carbon in the forest are the
ones with the densest wood and with seeds that are dispersed by birds and mammals, and they
are typically rare per hectare. If those birds and mammals disappear as a result of hunting,
the rare trees over time are likely to be replaced by an aggregation of trees that have much
lower carbon densities and much lower diversity. If soaking up carbon dioxide is a global
benefit conferred by tropical rain forests, then monkeys and large fruit-eating birds, by the
seeds they disperse, help to create the most carbon-dense forests. We can thus see how the
loss of primates and birds from a rain forest not only removes a keystone species but also
contributes to a trophic cascade, a process that typically leads to a more impoverished, less
stable environment.
If monkeys, macaws, and jaguars are so ecologically valuable, how can we make them
worth more alive than dead to the local people—those who live in or at the edge of the rain
forest and rely on its bounty? George has been working closely with Adrian Forsyth and their
Peruvian colleagues to design a network of parks and conservation areas to keep this Amazo-
nian region as intact as possible. If jaguars need a lot of space and the largest reserves are
still too small to hold what biologists consider a genetically healthy population, linking re-
serves through corridors jaguars use can greatly enhance the conservation effect. Maintaining
connectivity between reserves increases movement and ultimately gene flow. In the Amazon,
such landscape-scale conservation with respect to large predators and other roamers is still
possible with the proper incentives. One promising program, called the wildlife premium
mechanism, would pay poor Peruvians who collect Brazil nuts for a living to become stew-
ards of the forests and protectors of jaguars and pumas. By agreeing to maintain the dispersal
corridors for jaguars among Manú National Park, Tambopata National Reserve, and nearby
Alto Purús National Park, the communities could help secure a landscape of several million
hectares and receive financial benefits. The plan, which is still in its infancy, may hold a key
to a future with jaguars and pumas and the best inoculation to a cascading decline of Amazo-
nian diversity beyond its treasured parks and reserves, where jaguars still venture out onto
the beach.
