Biology Reference
In-Depth Information
pearance of forests than through the current banking crisis, according to
an EU-commissioned study. It puts the annual cost of forest loss at between
$2 trillion and $5 trillion.”
A sense of the diversity in the lowland neotropical rain forest, which
covers 3 percent of the Earth's surface and contains 50 percent of its spe-
cies, is conveyed by comparing the number of vascular tree species in plots
1000 m
2
from the modern northern deciduous forest to the rain forest:
Ozark Mountains of Missouri, 23 species; tropical dry forest (Venezuela
and Costa Rica), 63; moist tropical forest (Brazil and Panama), 109; wet
tropical forest (Ecuador and Panama), 143; and superwet tropical forest
(Colombia), 258 (Gentry 1982). One factor involved in the tenfold differ-
ence in diversity is predation that can reach epidemic levels under the favor-
able year-round growing conditions. Wide spacing (fi g. 2.46) is one means
whereby these levels are kept low enough that some individuals and their
propagules survive.
People have occupied Brazilian Amazonia in relatively large numbers
and in a sustainably balanced system for at least 1500 years. The archeologi-
cal site of Upper Xingu has twenty-eight settlements, each with a popula-
tion of about 2500, for an estimated regional population of 50,000 people
(Heckenberger 2009; Heckenberger et al. 2008).
The Atlantic Forest
The young Darwin had his fi rst experience there with the tropical fauna and fl ora.
In 1836 on his way home on the “Beagle” Darwin visited Bahia for the second time
and had a strange premonition when he wrote: “In my last walk, I stopped again
and again . . . and endeavoured to fi x in my mind for ever, an impression which I
knew sooner or later must fail . . . the thousand beauties which unite these into one
perfect scene must fade away; yet they will leave, like a tale heard in childhood, a
picture full of indistinct, but most beautiful fi gures.” Not even the smallest remain-
der of a forest survives where Darwin stood.
—FRANCIS DOV POR,
Sooretama
, 1992
The dry vegetation on the crests of the Río São Francisco running the length
of the Brazilian highlands separates the Amazon from the Atlantic rain for-
est (Morellato and Haddad 2000). The southern boundary of the forest
once included the magnifi cent
Araucaria angustifolia
(fi g. 2.48), but condi-
tions are ideal for growing
Hevea brasiliensis
(rubber), and
Theobroma cacao
(cocoa), the harvesting of commercially valuable timbers for lumber (
As-
tronium concinnum
,
Cedrela odorata
,
Dalbergia nigra
,
Plathymeia foliosa
) and
