Procellariiform seabird recovery on islands after removal of invasive predators

Stephanie Borrelle (Institute for Applied Ecology New Zealand, Auckland University of Technology, Auckland, New Zealand) and colleagues has published in the journal Oryx on how well seabirds recover after their islands are freed of invasive predators.

The paper’s abstract follows:
“Protecting seabirds is a global conservation priority given that 29% of seabird species are threatened with extinction. One of the most acute threats to seabirds is the presence of introduced predators, which depredate seabirds at all life stages, from eggs to adults. Consequently, eradication of invasive predators has been identified as an effective and commonly used approach to seabird conservation. Seabird recovery following the eradication of predators is influenced by complex and interacting environmental and demographic factors, and there are gaps in our understanding of species-specific responses. We reflect on the recovery of seabirds on islands cleared of predators, drawing on the equilibrium theory of island biogeography, and synthesize key influences on recovery reported in the literature. We present a regionally specific case study on the recovery of seabird colonies (n = 98) in the Hauraki Gulf, New Zealand, which is a hotspot of seabird diversity (27 species), with a long history of eradications of invasive predators. We found that on islands cleared of predators seabirds recover over time, and such islands have more diverse seabird assemblages than islands that never had predators. Recovery appears to be influenced by a suite of site- and species-specific factors. Managers may assume that given enough time following eradication of predators, seabirds will recolonize an island. Although time is a factor, proximity to source populations and human activities has a significant effect on recolonization by seabirds, as do demographic traits, colonizing ability and habitat suitability. Therefore, integrating expected site and species-specific recovery responses in the planning of eradications should help guide post-eradication management actions.”

House Mice have killed this Atlantic Petrel chick on Gough Island, photograph by Ross Wanless

Reference:

Borrelle, S.B.,Boersch-Supan, P.H.,Gaskin, C.P. & Towns, D.R. 2016.  Influences on recovery of seabirds on islands where invasive predators have been eradicated, with a focus on Procellariiformes.  Oryx doi.org/10.1017/S0030605316000880.

John Cooper, ACAP Information Officer, 30 December 2016