Mammal responses to matrix development intensity



The landscape matrix is increasingly being recognized as important to biodiversity conservation. The nature of the matrix impacts the persistence of species in human-modified landscapes through its pervasive influence on adjacent habitat and through the habitat value of the matrix itself. However, previous studies have not isolated the effects of the matrix from the effects of other aspects of landscape modification, such as habitat loss and fragmentation, and much remains to be understood about the independent impact of the matrix on wildlife. We investigated the effects of the matrix on mammal abundance and landscape use in south-east Queensland, Australia. Mammals were surveyed in patch ‘core’, patch ‘edge’ and ‘matrix’ landscape elements along a rural–suburban gradient of matrix development intensity quantified by a weighted road-length metric, which was significantly correlated with housing density, while controlling for potentially confounding patch and landscape attributes. Response to increasing matrix development intensity was highly species-specific. Several native species declined in abundance; however, others were more resilient to moderate levels of matrix intensity, one species increased in abundance, and at least one species appeared unaffected by matrix intensity. Native species richness peaked at moderate levels of matrix development intensity. Exotic species richness and feral predators increased with matrix intensity and were negatively correlated with native species. Species response to matrix intensity appeared related to their use of edge or matrix habitat. An ability to use the matrix per se, however, may not translate into an ability to persist in a landscape where development substantially reduces the habitat or movement value of the matrix.