The role of Riparian habitats in forest mosaics in promoting Avifauna at the landscape scale

The importance of riparian habitats to bird communities is well documented internationally, however the value of these habitats in largely intact landscapes is less well understood, particularly in Australia. Thirty paired riparian and adjacent non-riparian sites were selected within extensive forest mosaics of the Victorian Central Highlands and were surveyed over a two year period. Bird assemblages occurring within riparian habitats supported a significantly greater richness, abundance and diversity of species. These assemblages were also found to have species compositions significantly different from those occurring at adjacent non-riparian sites separated by a distance of approximately 750 m. Differences were attributed to a suite of distinctive species and significant contrasts in the densities of a range of species that occur in both habitat types. At the landscape level, there was a strong patterning of the avifauna centred on riparian habitats. Bird assemblages typically comprised four distinct suites of species: 1. species widespread in forests and woodlands of southeastern Australia; 2. riparian associated species (wet forest intruders); 3. riparian selective species, and; 4. riparian avoiding species. Both physiognomic and floristic differences between riparian and adjacent non-riparian habitats appear to drive responses in the structure of bird communities. There exists a distinctiveness and variability among the range of vegetation types and associated bird assemblages occurring throughout the forest matrix, including in riparian habitats. The occurrence of complimentary bird assemblages throughout the landscape mosaic highlights the importance of whole landscape planning for avifauna conservation.