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Thomas Crow
USDA Forest Service
To me landscape ecology is the study of pattern and process
at the landscape level. Given that, the obvious question
is: What is a landscape? Attempts to answer this rather
simple question have proven difficult. The textbook definitions
such as a landscape is a “heterogeneous land area
composed of a cluster of interacting ecosystems” are
not helpful for defining the boundaries of a “landscape” and
perhaps this is best. Before getting too upset about
the lack of consensus about what it is, the important
points are that the basic units of landscapes are ecosystems
(in fact, the term landscape ecosystems is used by some)
and that the landscape fits somewhere between a local
view of the world (e.g., a forest stand) and a regional
view (e.g., the Great Lakes region of the United States).
Like
so many colleagues, my first rigorous exposure to landscape
ecology was from the book "Landscape
Ecology" written by Richard Forman and Michel
Godron published in 1986. In addition to this seminal
work, however, many other thoughtful people have contributed
to my understanding of landscape ecology. One such
defining moment was another book -- The Living Landscape,
Basic Books, 1962, and written by the pioneering ecologist,
Paul Sears – that I purchased for 75¢ at
a bookstore in Princeton, New Jersey. In this book,
Sears writes:
Most of us, without knowing it, are afflicted
with a kind of blindness which vastly decreases both
the
joy of living and our effectiveness as responsible
citizens. We do not see, let alone comprehend, the
living landscape through which more of us, each year,
move along through ever greater distances. Or as we
fly over it on clear days, we pass the time in chance
talk or transient reading, unable to learn from or
even be entertained by the magnificent panorama unrolling
beneath us.
When I fly, I generally have my nose pressed
to the airplane window looking at the panorama below.
What
I see are landscapes. And the patterns that I see reflect
the complex interactions between the physical environment
and human land use. These patterns profoundly affect
the benefits that people derive from the landscape.
As a forest ecologist, this view forces me to think
much more holistically about forests and how they interact
with other landscape elements such as wetlands, rivers,
agricultural and urban lands. It also forces me to
think more holistically about people, their values
and perceptions, and the conditions that we create
through resource management and, more broadly, through
land use.
This view from "above the forest" is essential
for dealing with many of our critical problems in managing
natural resources. Resource managers are trained to
deal with the pieces – individual species or
individual forest stands – but this piecemeal
approach to management is not working very well. When
the view of the forest “from above” is
combined with the more traditional view of the forest “from
within,” only then is the integration sufficient
to deal effectively with the growing demands for an
array of products and benefits, many of which are in
conflict, from a finite land and water base. Because
these demands are ever increasing and because the landscape
and waterscape are indeed finite, we are approaching
the day when it will be necessary to more formally
design a landscape to meet multiple objectives if issues
such as keeping productive forests in timber production,
providing critical habitat for endangered species,
or maintaining remoteness as a quality in at least
some landscapes are important to people. How we accommodate
these disparate land uses is the question, and landscape
ecologists have some of the answers. This is an exciting
opportunity for ecologists to practice their science
and to make a difference in the real world.
About Thomas Crow
I am the National Program Leader for Ecological Research for Wildlife, Fish,
Air, and Water Research, USDA Forest Service, in Washington, D.C. My interests
are in bridging the science of landscape ecology with its application for managing
wildlife and fish as well as for keeping our air and water clean. The Forest
Service manages 191 million acres of public lands in national forests and grasslands,
an area equivalent to the size of Texas, so the opportunities and challenges
for managing landscapes are immense. Planners and managers in the Forest Service
generally recognize the need for landscape management. What is less obvious
to them is how to do it.
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