Fragmentation – Measures and indicators
Chair: Jochen Jaeger, Concordia University Montréal, Québec, Canada.
There is an increasing need and interest in including indicators of landscape fragmentation in monitoring systems of sustainable landscape management. However, most monitoring systems today still lack any indicator of landscape fragmentation. One likely reason is that there is considerable debate and confusion about the exact definition of “landscape fragmentation“ and how it can be measured, which impedes agreement about which of the proposed metrics should be used (Kupfer 2006).
The monitoring systems for biodiversity and sustainable development in Switzerland have recently adopted an indicator of landscape fragmentation (Jaeger et al. 2008). The measure used to quantify this indicator is called “effective mesh density” (number of meshes per 1000 km2). Data on the degree of landscape fragmentation reveal an increase by 230% during the last 120 years. The German Federal Environment Agency has recently suggested to introduce region-specific limits to control landscape fragmentation, using the “effective mesh size”.
We will discuss the issues involved in measuring landscape fragmentation and the requirements for metrics of landscape fragmentation (suitability criteria), and compare the strengths and weaknesses of various metrics of landscape fragmentation. We will discuss the “effective mesh size” and „effective mesh density“ in more detail. We will also investigate how habitat amount and habitat fragmentation per se can be measured separately, i.e., that they are conceptually independent. We will look at many practical examples which will make the participants comfortable in using these metrics.
Girvetz, E.H., Thorne, J.H., Berry, A.M., Jaeger, J.A.G. 2008. Integration of landscape fragmentation analysis into regional planning: A statewide multi-scale case study from California, USA. – Landscape and Urban Planning 86: 205-218.
Jaeger, J., Bertiller, R., Schwick, C. 2007. Degree of landscape fragmentation in Switzerland: Quantitative analysis 1885-2002 and implications for traffic planning and regional planning. Condensed version. Swiss Federal Statistical Office, Neuchâtel, Bestellnr. 868-0200, 36 pp.
French Version: Morcellement du paysage en Suisse: Analyse du morcellement 1885-2002 et implications pour la planification du trafic et l’aménagement du territorire. Bestellnr. 867-0200.
Jaeger, J.A.G., Bertiller, R., Schwick, C., Müller, K., Steinmeier, C., Ewald, K.C., Ghazoul, J. 2008. Implementing landscape fragmentation as an indicator in the Swiss Monitoring System of Sustainable Development (MONET). –Journal of Environmental Management 88(4): 737-751.
Kupfer, J.A. 2006. National assessments of forest fragmentation in the US.Global environmental change – human and policy dimensions 16(1): 73-82.