Environmental Engineering Reference
In-Depth Information
3
Landscape: spatial interactions
Rudy van Diggelen
3.1 Relevance of landscape processes
for restoration ecology
3.2 Concepts
3.2.1 Landscape
Not so long ago ecological restoration was mainly
seen as a technical activity where measures were
taken at a certain spot in case of an unwanted
situation or unwanted developments. However, it is
becoming increasingly clear that ecosystems do not
function independently from their surroundings and
that spatial relations matter a great deal. It is here
that restoration ecology is starting to adopt ideas
from the field of landscape ecology. When MacArthur
and Wilson (1967) published the theory of island
biogeography, they stated that extinction increased
with decreasing size of the island and immigration
decreased with increasing distance from the mainland.
This theory has been applied in the case of isolated
nature reserves within an intensively used landscape
and has had a large impact on theories of landscape
planning. By the beginning of the 1980s the field
of
ecohydrology
was developing in north-west
Europe (Succow 1982, Grootjans
et al.
1996) and it
became increasingly clear that water flows connect
wetland sites. Human activities in one particular area
may cause disturbance in another, sometimes distant,
area and can indeed affect restoration perspectives
significantly (van Diggelen
et al.
1995). The same is
true for airborne pollution (Bobbink
et al.
1998).
Insights in landscape relations are therefore essen-
tial when evaluating the restoration perspectives of
degraded sites.
The scientific concept of landscape has its roots in
central Europe and was mainly developed by German
scientists (Troll 1939, Schmitthüsen 1963). At that
time the concept seemed rather clear and was exclus-
ively viewed from a human perspective. A typical
Landschaft
was many square kilometres in size and
included several villages, farms, etc. For those
researchers there was no doubt that cultural elements
should be included in the concept. Later work, espe-
cially in less densely populated areas, did not auto-
matically assume that a landscape should be viewed
at the human level and much less emphasis was put
on the cultural aspect. As a consequence the concept
became increasingly vague and two subsequent ana-
lyses of papers in
Landscape Ecology
by Wiens (1992)
and Golley (1995) showed no clear trend in para-
meters such as scale of research, level of organization
or subjects of study. The only elements the papers
had in common were that they were all concerned
with spatial relations and they were all published
in
Landscape Ecology
! In the present chapter we will
adopt a practical approach and define landscape as
a spatial matrix at the human scale in which inter-
actions of biotic and non-biotic elements take place.
In comparison to other ecological concepts such as
ecosystem or population, a landscape is a very con-
crete part of the surface of the Earth, with boundaries
and a history. Typically it has a size of at least a few
square kilometres and can be photographed or put on
a map.
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