Methodical basis for landscape structure analysis and monitoring: inclusion of ecotones and small landscape elements
When the term landscape emerged in the 16th century it was coined by the perception
of nature in its holistic appearance, i.e. of the wholeness of the visible nature more or
less shaped by a location- and time-dependent mixture of anthropozoogenic impact. The
“scenery” comprising all the visible elements of a landscape was understood as an
aesthetic impression of ostensibly harmonious patterns of a composition of organic and
anorganic objects. Accordingly, it was through the fine arts, that by the painting of
landscapes the term per se was invented during the late Renaissance (Gombrich 1966).
Only during the late 18th and early 19th century the term was scientified by natural
scientists such as Alexander von Humboldt, who nevertheless still relied to the
(aesthetic) holistic concept of landscape, but at the same time tried to set up a
categorisation of the types of elements which “construct” it (Humboldt 1849). Efforts were
made to define landscape as a quantifiable multi-layer and multi-scale structure which
is solely characterised by specific landscape elements which form ecotopes (“landscape
cells”). The mosaic-like concinnity of ecotopes creates the landscape which is
experienced as a consistent entity (Troll 1939).
Modern landscape ecology understands landscape as a heterogeneous area, which is
coined by an aggregate of land forms or an association of habitats and which may
comprise an area from some hectares up to hundreds of square kilometres (Turner et
Gardner 1991). Three characteristics describing the typology of landscape are generally
stressed, explicitly structure, function and change. Structure refers to relations of
ecosystems in terms of shape, extent, abundance and configuration of components.
Function relies to interactions of elements in space and time, i.e. flows of energy,
material or organisms. Change describes the dynamics of structures and functions in a
spatio-temporal context (Forman et Godron 1986).
Referring to structural characteristics it is obvious that the well-introduced patch-corridormatrix-
model is of limited reliability when extending the approach towards relief
information, i.e. the third dimension in terrain description (digital surface/terrain models)
as well as when integrating transition zones or gradients between patches. These
ecotones have a significant temporal dimension in terms of dynamics of change and
have thus a strong influence on parameters describing interrelated ecosystems.
Improved approaches to a three-dimensional assessment and analysis of ecological
gradients have to take into account that transition between ecological, geographical and
environmental entities is generally non-discrete, often fuzzy. This aspect does not only
concern relations between landscape elements and land use and land cover categories
(describable by fuzzy logics) but also variations of approaches of analysis at multi-scale
levels up to the dispersion of populations in respective areas of distribution. An
ecological gradient can be described statistically by the fact that the variance of the
relevant parameter increases with growing distance from the reference area (landscape
element, habitat). It has nonetheless to be asked what would happen if that proportion
were affected by diffuse impacts, which cannot be expressed by discontinuities in relief
(e.g. in terms of canopy surface gradients from forest edges to adjacent copses and to
grassland or agricultural land), such as environmental (human) impact varying locally
both in time as well as in space, e.g. imission via air pollution or disturbances by tourism.
Advanced technologies of 3D-topographic data acquisition such as Airborne Laser
Scanning (ALS) as well as object-oriented approaches of remotely sensed image
analysis (OBIA) allow for detection and mapping at very high geometric (spatial)