Networks of small habitat patches can preserve urban bi...( Sets of small and seemingly insignif...)

Sets of small and seemingly insignificant habitat patches that are within reach for mobile species may under certain circumstances, as a group, provide an acceptable alternative to larger and contiguous habitats. This finding can make preservation of important ecological functions possible even in urban and other heavily exploited areas.

The study by Dr. Erik Andersson and Dr. rjan Bodin at the Department of Systems Ecology, and Stockholm Resilience Centre, both at Stockholm University, is unique in the sense that they empirically test and verify an often used modelling approach where habitat fragments are seen as individual nodes in larger networks of interconnected habitat patches.

According to the study, published yesterday in Ecography, sets of small habitat patches can host species that require much larger habitat patches for their daily needs than what each patch itself can provide. Many species are actually capable of moving back and forth between neighbouring patches, given that they are not perceived as being too far apart. Thus, many species are able to make use of the total of the habitat fragments in the network instead of relying on the individual habitat patches for their persistence.

"By defining the habitat patches as parts of a larger network, spatially explicit analyses of how the sum of the patches contributes to species dynamics on the level of landscapes are possible" said Dr. Andersson.

In human dominated areas, such as cities or intensively cultivated landscapes, it is often impossible to set aside large contiguous areas of natural vegetation. Instead, when multiple users compete for a limited area of land, only smaller pockets of natural vegetation (or just green areas) can realistically be preserved.

"Land managers need comprehensive and reliable tools that could help them to direct their conservation efforts to habitat patches where they get as much biodiversity as possible given a
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