With generations of undisturbed tropical forest growth, Rio Abiseo National Park holds ecological signposts for the future and shrouded monuments to the past
In Rio Abiseo National Park, in the upper elevations of Peru's eastern Andes, rivers rise and drop, sometimes in less than an hour. Landslides abruptly peal down slopes. Trees fall and other plants strive to occupy the resulting openings in the forest canopy. Perhaps this dynamism seems counterintuitive because, within the forest, the moss-laden trees and cool temperatures create the illusion of living museums, of ancient landscapes. And, in fact, plant growth is not especially fast here, but it is constant--twelve months a year and with ample moisture. If it does not rain every day, there are at least clouds that at certain elevations touch the forests. These mountainous cloud forests receive the full brunt of moisture arising from the western Amazon basin, condensed into rain clouds by the uprising and westward-bound trade winds.
It is easy to imagine, then, that botanical exploration might be difficult, but rewarding. Very few scientists have visited these environs and then only for a short time. New species are waiting to be found as well as unique adaptations to the rigors of the environment. The park is a living laboratory that invites us to examine the recovery of ecosystems--following disturbances caused by natural processes and those created by people in the distant and not-so-distant past.
The fact that the forests of Rio Abiseo National Park can recover is surely one of the few optimistic notes in a chorus of environmental disaster music heard as tropical forests are cut and converted into wastelands. Why and how these forests could regrow is still unknown, but might simply be due to the several centuries that have passed as no person sought to farm or bum these landscapes. Surely the opportunity of examining change after turning over ecosystems to the vagaries of natural processes is one of the principal reasons that a national park should be established. Rio Abiseo provides such "experiments" for researchers to study.
An irony is that although the park's western boundary is a two-day walk from the nearest house, a careful observer will find evidence that people have contributed to change by affecting the vegetation. Trees grow on top of rock walls that formed houses and ceremonial structures five hundred to one thousand years ago. And the use of the high-elevation grasslands for raising cattle in this century has left its own mark on the landscape at timberline. Probably this is a general truth about the eastern Andes and western Amazon: Virgin forests do not exist, and some degree of human intervention can be found even in the most isolated of sites.
The only way to identify species and to evaluate species richness is to collect plant specimens. This requires the taking of samples of the leaves and of the flowers or fruits. Each sample is then field pressed until they can be properly dried and prepared as herbarium specimens. The inventory of the park's plants will surely still be ongoing well into the next century. In the meanwhile, more than a thousand plant species have been provisionally identified, with about 350 growing in the high elevation grasslands and the remainder in the montane forests. More than a dozen are species new to science, and others are rare species restricted to northern Peru.
The study of vegetation also requires determination of what; life forms they belong to (such as tree, shrub, or forb) and measurements of how much space they occupy. Above timberline are grasslands dominated by bunch grasses, wetlands of sedges and rushes, and rocky hill slopes upon which other tropical alpine plants survive. Within the montane forests, there is much heterogeneity, with some forests reaching over one hundred feet in height. Other forests are less than ten feet tall and are found at the environmental extremes: at the uppermost elevations at which trees can grow or on rocky ridges with shallow soils. …