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M. Deconchat et al. 2010. Identification and characterization of forest edge segments for mapping edge diversity
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Adjacent land cover was measured with a spatial query between the summit of the transect and a
land cover map obtained in our case from the same remote sensed image treatment as the input
forest map.
Legend
In order to be able to map the diversity of edge segment, for visual interpretations and
communication, we defined a system of symbols for edge segments based on the transects. They
appeared on the map as pin-like symbols, with a color and a shape of the pin-head defined
according to the characteristics of the edge segment (Figure 1).
3. Results
Figure 2 is an example of a result map with a focus on small area in order to show clearly the
symbols that were used to display the different types of edge segments. Visual interpretation of
the map, which would be statistically confirmed by an analysis of the attribute table, indicates
that, in this very small area, meadow seemed to be the more frequent as an adjacent land cover
for woods 3 and 4 than for the others, more in contact with crops. Wooded elements of the
landscape (loop, branch, forest defined according to GUIDOS) were in the near vicinity of all
the woods.
4. Discussion
Interfaces and interactions between forests and the other land covers in landscape are becoming
focus questions for land management in the perspective of global changes. Our method,
Mapedge, contributes to provide managers with a new set of tools to take these interactions into
account in their decisions. For example, metrics based on edges can provide measures of
landscape fragmentation to be compared with area based metrics (McGarigal et al., 2009). Some
edge types may be more sensitive to landscape changes than other (Taylor et al., 2008). The
feasibility of edge diversity mapping has been demonstrated with our first results.
Mapedge is an efficient method to identify and characterize edge segments in landscape.
Despite the need to combine several tools to process the data, the Mapedge methodology is
rather simple and easy to apply. The number of parameters has been reduced as much as
possible and rules have been defined to select their values. We are now testing several sets of
parameters in order to assess how they influence the final output of the method (sensibility
analysis). In a near future, we will set up a unique tool that will apply all the treatments which
are separated for the moment. From a landscape ecology point of view, our method will provide
new landscape descriptors that will give a higher role to interfaces in landscape analysis.
References
Alignier, A., Deconchat, M., 2010. Variability of forest edge effect on vegetation implies to
reconsider its assumed hypothetical pattern. Applied Vegetation Science (submitted).
Esseen, P.A., Jansson, K.U. and Nilsson, M., 2006. Forest edge quantification by line intersect
sampling in aerial photographs. Forest Ecology and Management, 230:32-42.
McGarigal, K., S. A. Cushman, M. C. Neel, and E. Ene. 2002. FRAGSTATS: Spatial Pattern
Analysis Program for Categorical Maps. Computer software program produced by the
authors at the University of Massachusetts, Amherst. Available at the following web site:
www.umass.edu/landeco/research/fragstats/fragstats.html
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.