A framework for conceptualizing human effects on landscapes and its relevance to management and research models

The concept of habitat fragmentation is limited in its ability to describe the range of possible landscape configurations created by a variety of dist urbances This limitation is especially problematic in landscapes ;where hum an use of the habitat matrix occurs at multiple levels and where habitat mo dification may be a more important consideration than a simple binary class ification of habitat versus nonhabitat. We propose a synthesizing scheme th at places intact, variegated, fragmented, and relictual landscape states on a continuum, depending on tbe degree of habitat destruction. At a second l evel, the scheme considers the patterns of habitat modification that are im posed on remaining habitats Management for conservation involves halting an d sometimes reversing the trends of habitat destruction and modification. C onservation strategies will differ according to the state of alteration of the landscape but all strategies include some consideration of the degree o f modification of the matrix in determining habitat viability It is conveni ent for biologists to assess landscape alteration state in terms of the per sistence of large structural elements such as trees. Because animal species use habitats differently, however, they also experience the landscape diff erently A landscape considered structurally fragmented by humans may be fun ctionally variegated to other species. Therefore, it is necessary to consid er the extent to which the entire landscape including the matrix, is access ible and utilized by organisms with different spatial scales of resource us e.