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John Wiens
The Nature Conservancy
"Space … the final frontier." This
could easily be the mantra, not just of Star Trek, but
of landscape ecology as well. For space, in an ecological
context, is the primary focus of landscape ecology. Landscape
ecology deals with the causes and consequences of the
spatial composition and configuration of landscape mosaics.
Beneath the formalism of this definition, however, lies
a plethora of interesting, and important, questions.
How do the surroundings of an area influence what goes
on inside that area? What determines how "permeable"
the boundaries between different habitats are to movements
of individuals, nutrients, pollutants, or physical disturbances?
How do the attributes of boundaries influence such things
as microclimate or invasions of exotic species? How can
a landscape containing various land uses be managed to
promote the connections between otherwise isolated fragments
of forest, or grassland, or marsh? How do different places
in a landscape vary in their quality to organisms of
interest, and how can the quality of one habitat patch
influence the quality of its neighbors? What processes,
both natural and human, produce the patterns of landscapes?
How can these processes be managed to produce desired
landscape configurations? How do we determine what is
"desirable," for
whom or what? The list goes on.
Landscape ecology is also a science of scale. We now
know that all sorts of ecological phenomena change
depending on the scales of space or time on which they
are viewed. We also know that patchiness of habitats
in space – spatial heterogeneity – occurs
at many scales of resolution. The effects of heterogeneity
on the behavior and dynamics of individuals, populations,
communities, and ecosystems are different at different
scales, so understanding the scale-dependence of these
heterogeneity effects is important to ecology, whether
basic or applied. Landscapes, at various scales, provide
a handy way of conceptualizing and studying this heterogeneity.
Landscape ecology, then, considers not just what things
are, or how these things change over time – these
are the domain of traditional ecology – but where
things are, at multiple scales. The "where" – the
locations relative to other things – is what
places the things of interest in the context of a landscape.
But because most landscapes on earth are influenced,
if not dramatically altered, by human activities, humans
and their actions become part of the study. This is
one reason why landscape ecology is so relevant to
conservation, resource management, and land use planning.
Because of the close linkages with human actions, landscape
ecology is also of necessity (as well as by its genealogy)
an intensely interdisciplinary area of study. The linkages
with human geography, spatial statistics and analysis,
remote sensing, computer modeling, land use planning,
landscape architecture, and, of course, ecology are
especially tight.
About John Wiens
For several decades I was an academic, teaching undergraduate and graduate
courses in ecology, behavior, ornithology, and landscape ecology. In 2002 I left
the hallowed halls to join The Nature Conservancy, where I am now Chief Scientist.
Here I am responsible for promoting the infusion of science into conservation
practice, following from the premise that conservation that is well grounded
in science is better than conservation that is not. Much as we might like to
think that conservation and science are joined at the hip, in reality they are
not. The links between ecology and conservation science are indeed growing stronger – witness
the many papers in Conservation Biology, Biological Conservation, Ecological
Applications and the like. But there remains a gap, or perhaps even a chasm,
between the worlds of science and that of conservation practice and action. The
challenge is to bridge that gap, and it’s my belief that landscape ecology,
with its multi-scale perspective, its emphasis on spatial relationships, and
its explicit recognition of human land use and its causes and consequences, is
uniquely positioned to be the bridge. We’ll see.
Looking back,
I realize that I must have been a landscape ecologist before there was "landscape
ecology." In my Ph.D. dissertation, on community
relations among grassland birds, for some reason I thought it a good idea to
use a measure of the distance from territories of various species to the nearest
woodland edge in my analyses. Such measures are commonplace now, but they weren’t
in the early 1960s. My interests in spatial patterns and their effects, and
in scaling issues, continued to grow as I shifted attention from birds in grasslands
to birds in western shrub deserts, even including a brief foray into amphibian
behavioral ontogeny. When landscape ecology emerged as a new discipline in
North America in the 1980s, all of these interests found a comfortable conceptual
home, and I’ve called myself a landscape ecologist ever since. Short
of the Starship Enterprise, it’s the best journey one could make!
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