looked closely at the two extremes of the continuum.
One was called the BAU model, as in “business as usual.”
The other was termed the “governance” scenario, which
assumes a best- case outlook involving much greater
implementation of environmental legislation and more
careful and sophisticated use of the land than presently
occur. The BAU model predicts that by 2050 there
will be a loss of 40% of Amazon forests, mostly due to
expansion of agriculture. In this calculation, a current
forest area of 5.3 million km^2 (2.04 million mi^2 ) would
decline to 3.2 million km^2 (1.2 million mi^2 ), to about
53% of its original area, by 2050. This would include
two- thirds of the forest cover in six major watersheds.
An estimated total of 32 (+/−8) Pg (petagrams) of
carbon would be released into the atmosphere. (A
petagram is equal to 1 trillion kg, so the estimated
release is 24– 40 trillion kg/53– 88 trillion lb of carbon.)
To estimate the impact on biodiversity, the researchers
used non- flying mammals as indicator taxa. Under the
BAU projection, one- fourth of the 382 mammalian
species would lose more than 40% of forest within
their ranges. Thirty- five primate species would stand
to lose 60– 100% of their Amazonian ranges (100%, of
course, means local extinction). Ecosystems most at
risk include major watersheds, savanna, closed- canopy
forest, and wetland forest, which taken together
compose most of Amazonia. Most deforestation would
be concentrated in the eastern Amazon.
Under the governance model the projections suggest
less severe impacts. The model predicts about a two-
thirds reduction compared with the BAU model in
the numbers of threatened watersheds and mammal
species, as well as far less carbon emission. The
model assumes a planned expansion of protected
areas (PAs) from 32% to 41% of the total forest area
and that 100% of the forests within PAs are kept
intact. Only 50% of the forests outside PAs would be
subject to any form of deforestation. The researchers
suggest that the governance model would be more
likely if developed countries were willing to pay to
make “frontier governance” more politically feasible.
They urge consideration of sale of carbon credits as
well as environmental certification (meaning close
government oversight) of beef, soybean, and timber
production. They also urge strong action to encourage
conservation on private lands.
Questions arise about the degree to which
conservation goals, which typically focus on
biodiversity preservation and maintenance of intactforests, are compatible with increasing human usage of
the Amazon’s resources. As John Terborgh (2000) and
many others have stated, there is a divide between what
is perceived as good for people and what is good for
nature. If biodiversity and ecosystem services are good
for all of Earth’s people, why should a small percentage
of Earth’s people (such as subsistence farmers in the
tropics) bear the economic burden of biodiversity
preservation?
Acronyms have become popular in these
discussions. REDD stands for “reducing emissions
from deforestation and forest degradation.” PES stands
for “payments for ecosystem services.” EEFD stands for
“ecological- economic farm diversification.” The EEFD
approach was investigated for local land use near
Podocarpus National Park in southern Ecuador, as
documented by Thomas Knoke and colleagues. More
than 500 bird species and 40 mammal species have been
documented to occur within the park and surrounding
area. The park is located in a relatively high montane
zone where there is extensive farming. This activity has
led to overused, degraded, and abandoned land parcels.
The high elevation of the park results in a slow process
of secondary succession, exacerbating the problem of
land recovery. Farmers near the park normally use
pastures for only a few years and then abandon them,
promoting degradation. The EEFD model examined
a small, 30 ha (74 ac) farm that included 10 ha (24.7
ac) of previously degraded wastelands. The EEFD
model focused on active reforestation of degraded
land using a native tree species, Andean Alder (Alnus
acuminata). It is worth noting that many reforestation
projects do not rely on native species but instead use
various eucalyptus and pine species that, because
they are exotic species, have no value with regard to
biodiversity. Andean Alder grows quickly and adds
much nitrogen to the soil. Commercial harvesting of
Andean Alder may commence as early as a decade past
planting, but the model predicts peaks in revenue in
years 20, 30, and 40, when various crops of Andean
Alder are harvested.
The model requires diversification in land use,
combining limited logging with agriculture and
restoration. A rotational and sustainable system is
established that does not require encroachment on
protected areas. The point was made that market
values for agriculture and logging are uncoupled so
that, for example, if the price of timber drops in a given
year, the economic loss may be buffered by good cropchapter 18 the future of the neotropics 385