impact of thematic resolution on the patch-mosaic model of natural landscapes

We argue that thematic resolution, i.e., the level of categorical detail of a thematic map expressed by the number of classes included in the map legend, is an inherent component of the scale at which a landscape is analyzed. Changing the number of classes can change the configuration of the patch m...

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Bibliographic Details
Published in:Landscape ecology 2009, Vol.24 (1), p.15-23
Main Authors: Castilla, Guillermo, Larkin, Kerry, Linke, Julia, Hay, Geoffrey J
Format: Article
Language:English
Subjects:
Animal, plant and microbial ecology
Applied ecology
Biological and medical sciences
Biomedical and Life Sciences
Ecology
Ecosystems
Environmental Management
Fundamental and applied biological sciences. Psychology
General aspects
Landsat
Landsat satellites
Landscape Ecology
Landscape/Regional and Urban Planning
Life Sciences
National parks
Nature Conservation
Remote sensing
Sustainable Development
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Summary:We argue that thematic resolution, i.e., the level of categorical detail of a thematic map expressed by the number of classes included in the map legend, is an inherent component of the scale at which a landscape is analyzed. Changing the number of classes can change the configuration of the patch mosaic as much as changing the grain does. We address recent calls in this and other journals to deepen research in this topic. In particular, we report how thematic resolution affects the patchiness of mosaics representing natural landscapes, which have seldom been studied in this respect. We selected seven 50 x 50 km landscapes within national parks, each representative of a world biome. We applied an object-based unsupervised classification to Landsat TM imagery of these landscapes using increasing numbers of classes, between 2 and 50, and derived curves of mean patch size and patch density for each site. Our results are consistent with previous findings in that the patchiness of output mosaics increases monotonically with increasing thematic resolution, with a higher rate of increase up to eight classes that declines until it becomes roughly constant for more than 16 classes. However, this constant rate of increase is still considerable, meaning that, at least for natural landscapes, there is no threshold beyond which the patch-mosaic model is independent of the conceptual filter applied. This dependence on human fiat calls for re-thinking the patch-mosaic paradigm.
ISSN:0921-2973
1572-9761
DOI:10.1007/s10980-008-9310-z