Conservation and Sustainable Use of the Biosphere - WBGU

Natural and cultivated landscapes
E 1
E 1.1
Classification of landscapes by geography and
function
Ecosystems, that is webs of biotic communities and
their abiotic environment (Section D 2.3), can be
described as three-dimensional physiographic units
(Leser, 1997) aggregated to varying degrees, whose
boundaries are defined by humans and cannot be
precisely determined – unlike those of organisms.
They range from ecotopes through to ecotope webs
(landscapes) and ecoregions (biomes) right up to
continents, the ocean and the globe. Like organisms,
they have structures and an ability to reproduce and
mutate (Section D 2).
Here, landscapes are viewed as ecosystems at a
higher degree of aggregation, ie as a mosaic or web of
various ecotopes that may have different sizes, structures,
functions and configurations. Landscapes can
be understood roughly as units that can be delimited
geographically and are largely independent of each
other, but are connected with each other via the
atmosphere, biosphere and hydrosphere. It is not
possible to make a clear delimitation here, since in
the longer term even apparently insignificant indirect
interactions between the units can lead to radical
changes.
Ecosystems with their various communities of
plants, animals, fungi and bacteria (Box E 1.1-1)
developed in an adaptation process under the influence
of the climatic, geochemical and biological conditions
of each site (Fig. E 1.1-1). In turn, however,
the biotic communities change their environment. If
we consider the diversity of site conditions worldwide,
ie climatic and geogenic diversity, it is hardly
surprising that a large number of ecosystem types can
be identified within which the characteristic living
communities have formed.
One example of such a large-scale global typification
is the categorization into biomes, such as that
undertaken by Prentice and Kaplan (1999). This is a
grouping of terrestrial ecosystems according to the
dominant plant types in each case, based on the old
observation that there is broad correlation in the
geographical distribution of plants and climates. The
result is a highly aggregated division into 28 biomes
that is suitable for showing the heterogeneity or
homogeneity of the global distribution of ecosystems.
Figure E 1.1-1
Structure and function of
site factors that shape
natural ecosystems.
Source: WBGU
Climate and weathering factors
Radiation
Precipitation
Humidity
Air temperature
Wind speed
Evaporation
Biological
Diversity
Limnic and marine factors
Water quality
Water depth
Addition of nutrients
Tides
Flow speed
Sediment composition
Geological/pedological factors
Parent rock (loose, firm)
Mineral composition
Relief
Exposure
Groundwater and dam water
Soils