|Applied Marine Ecology|
|Aquatic Species Ecology|
|Food Webs and Invertebrates Community Dynamics|
|Invasive Species (Wetlands)|
|Platypus Conservation Initiative|
|River Red Gum Dynamics and Management|
|Wetland Ecology and Stable Isotopes|
|Invasive Species (Terrestrial)|
|Spatial Analyses and GIS|
|Vegetation Survey and Mapping|
Coastal lagoons, while providing crucial habitat for a wide range of biodiversity, are often under intense urbanisation pressures resulting in their degradation. Insectivorous bats utilise these highly productive ecosystems and are directly impacted by their decline in quality. We compared bat activity and richness with prey biomass across a gradient of lagoon quality in coastal lagoons of Greater Sydney to determine the extent to which bats and their prey were impacted by lagoon degradation. Next, we honed in on the mechanisms behind insectivorous bats’ decline in degraded lagoons by examining food web structure (using analysis of δ13C and δ15N stable isotopes) and heavy metal contamination of lagoon sediment, invertebrates and bat tissue. Insectivorous bat communities were found to comprise of more species and be more active at undisturbed lagoons. Australia’s only trawling bat, Myotis macropus, was absent from all low quality lagoons. Heavy metal contamination of coastal lagoons is a significant source of degradation. Analysis of heavy metal concentrations in sediments, invertebrates and insectivorous bats confirmed that these contaminants were present at degraded lagoons and were operating within the trophic structures of these habitats. While trophic structure structure did not differ significantly with lagoon quality, M. macropus showed a small shift towards more δ13C enriched diets in low quality lagoons, potentially indicating avoidance of contaminated aquatic prey resources. The present study demonstrates that while coastal lagoons support a rich bat community, ongoing development of these habitats is likely to negatively impact on insectivorous bat species. Degradation has led to a disruption of food webs at coastal lagoons likely as a result of past contamination events rather than current contamination level.
|Clarke-Wood et al.||2016||The ecological response of insectivorous bats to coastal lagoon degradation||
Coastal lagoons provide key habitat for a wide range of biota but are often degraded by intense urbanization pressures. Insectivorous bats use these highly productive ecosystems and are likely to be impacted by their decline in quality. We compared bat activity and richness and invertebrate biomass and richness across a gradient of lagoon quality (9 lagoons) in the Greater Sydney region, Australia to determine the extent to which bats and their prey were impacted by lagoon degradation. Bats were more diverse and 19 times more active at higher quality lagoons. The trawling bat, Myotis macropus, was absent from all low quality lagoons, but these lagoons were used by other species such as Miniopterus schreibersii oceanensis. Invertebrate richness and biomass did not differ significantly across lagoon quality. We examined potential mechanisms of insectivorous bat decline at degraded lagoons by measuring toxic metal concentrations in bat fur, invertebrates and sediment. Lead and zinc were detected at environmentally significant levels in the sediments of lower quality lagoons. Furthermore, lead concentrations were 6 times the lowest observable adverse effects level for small mammals in the hair of one individual M. macropus. The present study demonstrates that coastal lagoons support a rich bat community, but ongoing development and pollution of these habitats is likely to negatively impact on insectivorous bat species, especially trawling species.
Tel: +61 2 9385 8296 | email: firstname.lastname@example.org | Address: Room 508, Building D26, School of Biological, Earth and Environmental Sciences, University of NSW
Authorised by Professor Richard Kingsford, Director | CRICOS Provider Code 00098G | ABN 57 195 873 179