Imogen Bassett (School of Biological Sciences, University of Auckland, New Zealand) and colleagues write in the journal Polar Biology on invertebrates associated with seabirds, including the ACAP-listed and Vulnerable Antipodean Albatross Diomedea antipodensis gibsoni and Sooty Shearwater Puffinus griseus, on Adams Island in the Auckland Islands group.
The paper’s abstract follows:
“Nesting seabirds import marine-derived nutrients into terrestrial food webs, affecting invertebrate abundance and community composition directly, through provision of decaying animal matter as a food source, and indirectly through effects on vegetation and prey abundance. Invertebrates have shown strong responses to seabird presence in some, but not all, ecosystems previously studied. In contrast to mainland range contractions, New Zealand’s subantarctic islands retain abundant seabird populations. We sampled ground invertebrates on mammal-free Adams Island, using pitfall traps. We surveyed sites in two vegetation types (tussock and forest) with either no nesting seabirds or nesting colonies of Gibson’s wandering albatross, sooty shearwaters or white-headed petrels. We collected 11 invertebrate orders and identified 20 Coleoptera species or higher taxa. The carrion beetle, Paracatops antipoda comprised over 50 % of Coleoptera individuals collected. P. antipoda was more abundant in forest than tussock and was positively associated with sooty shearwaters and negatively associated with white-headed petrels when compared with bird-free sites using a Poisson generalized linear model. Sooty shearwaters were also associated with elevated abundance of several herbivorous and invertebrate decomposer taxa. Nesting seabirds do appear to influence invertebrate community composition on Adams Island, but the direction of this effect appears to be taxa-specific. Further sampling with spatial replication of colonies is required to determine the extent to which these apparent taxa-specific responses are consistent across colonies and habitats.”
Antipodean Albatrosses on Adams Island, photograph by Colin O'Donnell
Bassett, I.E., Elliott, G.P., Walker, K.J., Thorpe, S. & Biggs, J.R. 2014. Are nesting seabirds important determinants of invertebrate community composition on subantarctic Adams Island? Polar Biology DOI 10.1007/s00300-014-1454-5.
John Cooper, ACAP Information Officer, 18 February 2014