Environmental Engineering Reference
In-Depth Information
Forests precede civilizations, deserts follow them.
F
RANCOIS
-A
UGUSTE
-R
ENÉ DE
C
HATEAUBRIAND
Human Population
Size and resource use
This chapter discusses how we can help sustain the
earth's terrestrial and aquatic biodiversity by protect-
ing places where wild species live. It addresses the
following questions:
Human Activities
Agriculture, industry, economic
production and consumption, recreation
How have human activities affected the earth's
biodiversity?
■
What are the major types of public lands in the
United States, and how are they used?
■
Direct Effects
Degradation and destruction
of natural ecosystems
Changes in number and
distribution of species
How should forest resources be used, managed,
and sustained globally and in the United States?
■
Alteration of natural chemical
cycles and energy flows
Pollution of air, water,
and soil
How serious is tropical deforestation, and how can
we help sustain tropical forests?
■
What problems do parks face, and how should we
manage them?
■
Indirect Effects
Climate
change
Loss of
biodiversity
How should we establish, design, protect, and
manage terrestrial nature reserves?
■
How can we protect and sustain aquatic
biodiversity?
■
Figure 8-2
Natural capital degradation:
major connections
between human activities and the earth's biodiversity.
What is ecological restoration, and why is it
important?
■
What can we do to help sustain the earth's
biodiversity?
■
8-1 HUMAN IMPACTS
ON BIODIVERSITY
KEY IDEAS
■
Human activities have depleted and degraded
some of the earth's terrestrial and aquatic biodiversity.
These threats are expected to increase.
Science and Economics: Effects of Human
Activities on Global Biodiversity
We have depleted and degraded some of the earth's
biodiversity, and these threats are expected to
increase.
Figure 8-2 summarizes how many human activities
decrease biodiversity. You can also get an idea of our
impact on the earth's natural terrestrial systems in
Science Supplement 2 at the end of this topic by com-
paring the two-page satellite map of the earth's nat-
ural terrestrial systems (Figure 1), the two-page map of
our large and growing ecological footprint on these
natural systems (Figure 2), and the map of our ecologi-
cal footprint in the United States (Figure 3). According
to biodiversity expert Edward O. Wilson, “The natural
world is everywhere disappearing before our eyes—
cut to pieces, mowed down, plowed under, gobbled
up, replaced by human artifacts.”
Consider a few examples of how human activities
have decreased and degraded the earth's biodiversity.
According a 2002 study on the impact of the human
ecological footprint on the earth's land, we have dis-
turbed to some extent at least half and probably about
83% of the earth's land surface (excluding Antarctica
■
We should protect the earth's biodiversity because
of the economic and ecological services it provides.
■
Cutting down large areas of forests reduces biodi-
versity, eliminates the ecological services forests pro-
vide, and can contribute to regional and global cli-
mate change.
■
We can use forests more sustainably by emphasiz-
ing the economic value of their ecological services,
harvesting trees no faster than they are replenished,
and protecting old-growth and vulnerable areas.
■
We need to protect more of the earth's terrestrial
and aquatic systems from unsustainable use for their
resources by employing adaptive ecosystem manage-
ment and protecting the most endangered biodiver-
sity hot spots.
■
We need to mount a global effort to rehabilitate
and restore ecosystems we have damaged.
