Unifying research on the fragmentation of terrestrial and aquatic habitats fragmentation research: habitat patches, connectivity and the matrix in riverscapes

Abstract/Summary

SUMMARY
1. While Tthere is an increasing emphasis in terrestrial ecology on determining the influence of the area habitat that surroundsing habitat patches (the landscape ‘matrix’) relative to the focal habitat patch characteristics of the patches themselvesin terrestrial landscapes, research on these aspects in running-water ecosystems is still rather have been under-represented or at least, terrestrial ecologists did not really recognized parallel studies by stream ecologists. While stream ecologists have long considered the patchiness inherent in running-waters, their work has not been recognized in terrestrial landscape ecology. This is unfortunate, as it does not take full advantage of learning in these two systems, which are characterized by differences in e.g., geometric complexity, and offer opportunities to advance our understanding of conservation decisions in fragmented systems.
2. Here we outline conceptual foundations of matrix ecology for stream and river ecosystems (‘riverscapes’). We discuss how a hierarchical, patch-based perspective is necessarymay be useful for the explicit delineation of habitat patches and the surrounding matrix, through which we may identify two classes of habitat edges in riverscapes (i.e. edges between the terrestrial-aquatic interface and within-stream edges within streams).
3. Under this conceptual framework, we review discuss the role of the matrix in influencing between-patch movement, and resource quality y, and resource quantity within and among habitat patches in riverscapes. We also review identify types of empirical and modelling approaches which may advance our understanding of fragmentation effects in these systems.
4. We identify five key challenges for better improved understanding of fragmentation and matrix effects: (i) defining populations and the ir population status (i.e. quantifying the demographic contribution of habitat patches to metapopulation dynamics), (ii) scaling from metapopulations to metacommunites, (i.e. searching for generalities in species responses to landscape heterogeneity), (iii) scaling from metacommunities to metaecosystems, (i.e. exploring the interactive role of the terrestrial-aquatic and within-stream matrix effects on the flow of material and energy at the network scale), (iv) understanding temporal dynamics in matrix permeability, and (v) revealing the utility of different patch and matrix representations for modelling connectivity relationships.
5. Fragmentation of habitats is a critical issue in the conservation and management of stream networks acrossat multiple spatial scales. Although the effects of individual barriers (e.g. reservoir dams) are well documented, wWe argue suggest that a more comprehensive patch-matrix landscape model will improve our understanding of fragmentation effects, and improve management in riverscapes.

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