Biology Reference
In-Depth Information
One of the most cat-rich rain forests on Earth is a nearly unbroken belt of wilderness in
the western arc of the Amazon basin. In the secluded Madre de Dios region of Amazonian
Peru, we can examine how and why individuals of the wild cat family and other terrestrial
organisms inhabit great expanses but are relatively distant from one another. In this remote
Amazonian locale, enclaves also exist with no evidence that large cats have ever been hunted.
In such a sanctuary, we can see how rare rain forest mammals and birds, such as jaguars and
pumas, even at very low densities, influence the species-rich domain over which they rule.
On a sunny morning in August 2009, in the very heart of the Madre de Dios region, I joined
the husband-and-wife team of George Powell and Sue Palminteri to survey a stunning rain
forest panorama from the top of the canopy-viewing tower in Peru's Manu Wildlife Center.
Some fifty meters above the ground, I wondered what Rousseau would have chosen to por-
tray in the scene before me. Surrounding the tower was perhaps the world's richest natural
arboretum, a forest holding one-tenth of all bird species and enough as yet unnamed inver-
tebrates to fill several natural history museums. Acrobatic spider monkeys and their slow-
moving relatives, red howlers, appeared below. In a neighboring fig tree, brightly plumed
trogons and barbets decorated the branches. Flocks of tricolored scarlet macaws flashed by
at eye level, penetrating the forest with their cacophonous squawks. For these canopy resid-
ents—monkeys, macaws, and thousands of others—this is the sweet life on the breezy, green
roof of the rain forest. The chance to join them in this restorative stratum, even for an hour,
is a relief from the claustrophobia of the dark, dank forest floor. For the elevated naturalist,
the exhilarating climb to the top serves as a refresher course—a moment to ponder when our
ancestors, too, were arboreal.
The tropical rain forest is full of common species such as ants, nematodes, and fungi that
contribute heavily to the unseen machinery of an intact rain forest, yet it is a bountiful King-
dom of Rarities as well: Many living things in this landscape, from the tops of emerging giant
trees to the thin soils covering their roots, exhibit several forms of scarcity. Some insect spe-
cies exist only in the canopy of a single tree species, but there they mass in numbers. The
giant trees orchestrate life in the Amazon and create a three-dimensional stage for millions of
smaller organisms and staggering diversity, too: a single tree may hold more ant species than
are found in the entire British Isles. Yet the distribution of these trees is quite different from
that in England and western Europe, where a few elms, maples, beeches, or oaks may dom-
inate a large patch of forest. In the Amazon, particular trees, such as mahogany and members
of the Brazil nut family, may range eastward across Brazil but be spread out as individuals,
occurring maybe only once every few hectares, sometimes even more dispersed. The jaguars
and pumas that wander below their crowns and several of the monkeys that live in them also
range widely but are thinly distributed. The macaws that fly across the canopy also appear
across much of the lowlands but are locally scarce.
