Zur Erfassung von Flächenfragmentierung und struktureller Diversität

Abstract

Structural diversity is an important and difficult to measure landscape characteristic. It cannot be measured directly but is described by indices, that base upon measurable attributes such as number, size, shape and edge-length of individual areas and distance between areas.On the basis of a sample map the study analyses four principal properties of indices: Their ability to differentiate between obviously different structures, their mutual statistical independence, their scale invariance and the possibility to estimate them from samples.The indices LPI, LSt and MS1 proved to be suitable for an analysis of spatial structure. The fracta~ indices MPFD and DLFD showed less ability to differentiate between different structures, Unbiased sample-based estimates (using square windows of the entire map) are feasible only for indices which are composed of components which can be estimated without bias themselves (absolute area, length of edge). Also the fractal area/perimeter dimension gave good estimates in the sampling study.

Indicators to monitor the structural diversity of landscapes

“…Various indicators on forest fragmentation have been proposed by Oehmichen and Köhl (2006), Traub & Kleinn (1999) and Larsson et al (2001) and others. These include measures of edge lengths, the proportionate area, the Shape Index as well as the effective mesh size.…”

On the role of spatial stochastic models in understanding landscape indices in ecology

“…One of the most attractive features of LPIs has been their simplicity: one can summarize huge amounts of data in a single number (or by a limited set of numbers) without a priori knowledge of the landscape, its processes and organisms. A wide spectrum of views and interpretations quickly resulted in the development of several dozens of LPIs: some emphasized the shape of patches (LaGro 1991), some preferred characterizing edges of pixels (Hargis et al 1998, Trani and Giles 1999), and some focused on the diversity (Fortin et al 1999, Traub and Klein, 1999, Fjellstad et al 2001). Their widespread use was also boosted by freely available software (Baker and Cai 1992, McGarigal and Marks 1995).…”

Fernerkundliche Waldflächenerfassung im Kontext internationaler Umweltabkommen

“…Räumliche Muster entstehen durch Prozesse, die auf bestimmten Skalen stattfinden, auf anderen jedoch nicht beobachtet werden können (Gotway & Young, 2002). Mareceau & Geoffrey, 1999;Strahler et al, 1986;Woodcock & Strahler, 1987), für landschaftsökologische Fragestellungen (Benson & MacKenzie, 1995;Jelinski & Wu, 1996;O'Neill et al, 1996;Saura & Castro, 2007;Turner et al, 1989;Wu, 2004) und im Rahmen der Waldflächenerfassung (Frohn & Hao, 2006;Nelson et al, 2009;Traub & Kleinn, 1999;Zheng et al, 2009) Dabei soll getestet werden, ob das entwickelte Verfahren in der praktischen Anwendung funktioniert.…”