MEPS 384:23-31 (2009)  -  DOI: https://doi.org/10.3354/meps08037

ABSTRACT: In fragmented landscapes the matrix, i.e. the surrounding but different habitat, can have a strong influence on the biodiversity in fragments. The amount of natural habitat converted for urban use is increasing on every continent, so fragments of natural habitat are becoming more likely to be embedded in a matrix of human-made habitat, rather than other natural habitats. This is particularly prevalent on urbanised coastlines. Yet there has been little research to help us understand the dynamics and consequences of fragmented coastal landscapes. In Sydney, Australia, most of the natural intertidal landscape of Sydney Harbour (a mosaic of rocky shore, mudflats and sandflats) has been replaced by artificial habitat (such as seawalls). I tested the hypothesis that biota on rocky shores in Sydney Harbour would differ depending on whether shores were embedded in a matrix of artificial habitat (here called ‘complete fragments’), natural habitat (here called ‘natural patches’), or a mixture of the 2 types of matrix (called mixed fragments). Assemblages at mid-shore levels were significantly different among these types of fragments. At mid- and low-shore levels, assemblages were more variable in mixed fragments than in complete fragments and natural patches. The kinds of mobile and sessile taxa that contributed most to differences among fragments differed, depending on which types of fragments were compared. Many taxa were found in greater abundance in natural patches than in mixed or complete fragments, although not all comparisons were statistically significant. Artificial habitat seems to interrupt natural connectivity among local populations of intertidal marine organisms in this urbanised estuary.

KEY WORDS: Matrix · Conservation · Habitat structure · Intertidal · Rocky shore · Intertidal organisms