In the context of biodiversity, landscape metrics can be used to assess landscape patterns, to define the minimum equipment, to carry out isolation or connectivity analysis and to recognise and monitor the results in changing landscapes. Moreover, landscape metrics have come to play a considerable role in the analysis and assessment of biodiversity, especially in local studies of species distribution and modelling, analysing and characterising the diversity of landscapes (as part of biodiversity), and for monitoring. It can be stated that:
- Landscape metrics are applied in a variety of local studies and research projects. Only a few indices are used constantly in different studies. Thus, there is a lack of comparability of studies and problems in the formation of general statements.
- Landscape metrics are already used in monitoring, but there is no “standard set” of landscape metrics which is frequently used.
- Usually very simple measures are used, especially for planning purposes, because they are more demonstrative and more accessible to the public.
- In studies a large number of numerical values are often generated, but it should be kept in mind that many landscape metrics are highly correlated.
- Usually temporal dynamics are not considered, or not sufficiently considered. The ecological significance of a measured pattern is difficult to assess without an understanding of the historical variability of that pattern.
- Vertical complexity is too little considered. However, it can be important for habitat modelling (e.g., for birds). Some developments are currently in progress (McGarigal and Cushman, 2005; Hoechstetter, 2009; Hoechstetter et al., 2011), but further developments on ecological transitions and vertical structures appear necessary.
- A comprehensive overall view on the state of research is lacking.
Often, one finds only very general statements on the relationship between landscape structure and biological diversity. Generally, there is still a deficit in converting findings about individual species to general knowledge about the relationship between landscape structure and biodiversity (Turner, 2005, 331). The evaluation and prediction of species richness in complex landscapes remains a problem, because there is no simple scaling function of species diversity in a heterogeneous environment (Wagner and Edwards, 2001*, 121). At the species level, it is also difficult to postulate a general correlation between biodiversity and landscape parameters (Brotons and Rosell, 2001). Hence, for certain species, only land use is crucial; for others, the landscape structure in terms of relationships to neighbouring land uses or edge lengths of hedges, etc. are important (see also, e.g., Burel et al., 1998; Zebisch, 2002, 5). Moreover, the potential value of an area for conservation of biological diversity from the perspective of nature conservation does not depend on how many species are present, but rather which ones (Wagner and Edwards, 2001, 121). In addition, qualities of biodiversity which are recordable by landscape metrics are only a part of the reality. Biodiversity objectives should also be set on the basis of non-measurable qualities, such as natural beauty, wilderness and perceptibility of a landscape (Weinzierl, 2004, 20).
Overall, it can be stated that the possibilities for the application of indices of landscape structure for spatial planning and for environmental and nature conservation have not been fully exhausted. Since they are suitable as indicators of processes of land use development and environmental status, such indices should more than ever find their way into spatial environment monitoring and information systems.