The definition of landscape is very widely used, especially it depends on the different forms of research or management context, thus from which point of view you analyze the landscape patterns. In general it contains elements and patches of landscape. One precise definition from Forman and Godron (1986) describes landscape as a composition of different clusters of interacting ecosystems which are always repeated – the land area differs from landscape to landscape, so it is heterogeneous. The spatial range of landscape is important as well, for example the normal deposit of an organism and moreover its regional distribution. But we have
As we could read in the upper chapter, a mosaic of patches constitutes landscapes. As well as there is no consistent definition of landscape, there exist different angles to define the meaning of patches. One perspective is the ecological. (1) It involves especially the discrete areas. The other point of view is the organism-centered one, which describes environmental units. Patches also can be defined hierarchically in scales.
Analyzing landscapes within its mosaic of patches, the function of scale is to identify different patterns. Spacial scales of an ecological perspective could be extend and grain. Sometimes it is possible and necessary to get information about one scale to another.
Landscapes are open and not Isolated. It is necessary to detect the interactions between the landscape an the neighboring landscapes.
The structure of a landscape is characterized by its composition and configuartion.
One aspect of landscape structure is landscape composition. The landscape composition is defined by the distribution of the area into patch types. Each patch has a certain patch richness (PR) and a certain density of diversity. There are different diversity indexes (Shannon’s diversity index (SHDI), modified Simpson’s diversity index (MSIDI). Evenness is also an important aspect of landscape composition. The evenness index states the degree of constant distribution of a certain patch.
Landscape configuration is another aspect of landscape structure and is quantified by two metrics. One is the patch interspersion and the other is the juxtaposition. With these metrics it is possible to investigate the level of adjacency. The interspersion and juxtaposition index (IJI) can be used for raster and vector data sets.
Landscape metrics quantify specific spatial characteristics of patches, classes of patches, or entire landscape mosaics (MCGARIGAL & MARKS 1995, GUSTAFSON 1998) within landscape boundaries. Landscape metrics are divided into landscape configuration metrics and landscape composition metrics. But sometimes it is hard to attach a landscape metric to one of these. That depends with aspect you want to investigate. Landscape configuration and composition are both important for the landscape structure. Some emtrics are analyzing both aspects, some just one of them. “There are some landscape metrics that clearly represent pattern complexity but are not spatially explicit at all. “(MCGARIGAL & MARKS 1994, S.11)