Landscape issues for the macrofauna in temperate urban mangrove forests

Estuarine habitats along Australia's temperate shores generally comprise saltmarsh, mangrove forests and seagrass habitats. In urban areas these habitats have been progressively fragmented due to human population increase and industrial expansion. Saltmarshes are particularly vulnerable to urban expansion because of their close proximity to densely populated areas. However, there is limited understanding of what effect the reclamation of saltmarsh habitats has on the macrofauna in adjacent mangrove forests.We examined the importance of saltmarshes on adjacent mangrove forests at nine locations on the Parramatta River, Sydney, New South Wales.The habitats examined consisted of mangrove forests with and without an adjacent saltmarsh habitat.The diversity and abundance of macrofauna were sampled during spring 1999 and summer 2000. Overall, there was a trend for the diversity of macrofauna to be greater in mangrove forests with an adjacent saltmarsh compared to those with an adjacent park or bund wall. Macrofaunal diversity was 36% lower in mangrove forests without adjacent saltmarsh habitats. In addition, the diversity of macrofauna in mangrove forests adjacent to a saltmarsh showed the least variability, while those adjacent to a bund wall showed the greatest variability. This study has shown that the diversity and abundance of macrofauna in urban mangrove forests was correlated with the adjacent habitat, thus it is important to conserve remnant patches of saltmarsh in our urban environment.