Not seeing the ocean for the islands: the mediating influence of matrix‐based processes on forest fragmentation effects

Abstract

The pervasive influence of island biogeography theory on forest fragmentation research has often led to a misleading conceptualization of landscapes as areas of forest/habitat and 'non-forest/non-habitat' and an overriding focus on processes within forest remnants at the expense of research in the human-modified matrix. The matrix, however, may be neither uniformly unsuitable as habitat nor serve as a fully-absorbing barrier to the dispersal of forest taxa. In this paper, we present a conceptual model that addresses how forest habitat loss and fragmentation affect biodiversity through reduction of the resource base, subdivision of populations, alterations of species interactions and disturbance regimes, modifications of microclimate and increases in the presence of invasive species and human pressures on remnants. While we acknowledge the importance of changes associated with the forest remnants themselves (e.g. decreased forest area and increased isolation of forest patches), we stress that the extent, intensity and permanence of alterations to the matrix will have an overriding influence on area and isolation effects and emphasize the potential roles of the matrix as not only a barrier but also as habitat, source and conduit. Our intention is to argue for shifting the examination of forest fragmentation effects away from a patch-based perspective focused on factors such as patch area and distance metrics to a landscape mosaic perspective that recognizes the importance of gradients in habitat conditions.

Andean Land Use and Biodiversity: Humanized Landscapes in a Time of Change

“…Ecologic effects in this context would be those affecting species composition and abundance in particular patches and those that alter connectivity among patches. Connectivity for a particular species is affected by the distance, presence, type of dispersal corridor, and type of land cover that composes the matrix (e.g., Kupfer et al, 2006;Nascimento et al, 2006). The type and location of remaining habitat can be a critical feature for surviving native biodiversity (e.g., Devictor & Jiguet, 2007), as is the presence of corridors (Chetkiewicz et al, 2006).…”

Citizen Science as a Tool for Conservation in Residential Ecosystems

“…We propose to use citizen science for studying and managing residential ecosystems based on the idea that improving the wildlife value of the matrix (i.e., intervening area between remnant patches of natural habitat) will have positive impacts on a number of ecosystem elements and processes, such as species diversity and microclimate (e.g., Gove et al 2005, Fischer et al 2005, Kupfer et al 2006). In the case of matrices comprising residential lands, management efforts must involve recruiting residents and coordinating their activities.…”

Matrix mediates avian movements in tropical forested landscapes: Inference from experimental translocations

“…As forests become fragmented and converted to human-dominated habitats, natural movement patterns may become disrupted, leading to a loss of population connectivity (e.g., Fahrig, 2003). Until recently, studies of fragmentation have predominately focused on the effects of patch size and the isolation of forest remnants on extinction and colonization processes, while often failing to account for the role of intervening land cover (termed the ''matrix'') (Ewers and Didham, 2006;Kupfer et al, 2006). The ability of species to re-colonize habitat patches that have been locally extirpated (a process critical for regional population persistence) (e.g., Hanski, 1998), however, may be largely contingent upon the structure and composition of matrix habitats (Bender and Fahrig, 2005;Revilla et al, 2004;Ricketts, 2001).…”