Seabird metapopulations: searching for alternative breeding habitats

Abstract

Today, many seabird species nest in port areas, which are also necessary for human economic activity. In this paper, we evaluate, using a metapopulation model, the possibilities for creating alternative breeding sites for the Common Tern (Sterna hirundo) in the Rhine-MeuseScheldt estuary. We explore 22 scenarios that differ with respect to (1) loss of breeding habitat in port areas, (2) location and size of newly created habitat, and (3) coexistence of old and new habitat. Results indicate that loss of port area habitats results in a serious 41% decline in the breeding population. When the loss in ports is compensated for within the ports, the decline was negligible. Fourteen scenarios result in an increase of the Common Tern metapopulation. In these, extra breeding habitat is created outside the ports in fish-rich waters, resulting in a potential metapopulation increase of 25%. However, the period of overlap between lost and newly created habitat strongly affects the results. A gap between the removal of old and the creation of new breeding areas might cause a drop in the metapopulation level of 30%. The population recovery from this drop might take more than 100 years due to slow recolonization. Our results suggest that conservation of seabird species should be evaluated on a metapopulation scale and that the creation of new habitat may help to compensate for habitat loss in other areas. Furthermore, the results indicate that overlap between the existence of old and newly created breeding habitats is crucial for the success of compensation efforts. However, new locations should be carefully selected, because not only is the suitability of the breeding grounds important, but ample fish availability nearby is also key.

Colony size and not nest density drives reproductive output in the Common TernSterna hirundo

“…Schippers et al . () suggested creating artificial breeding habitat to replace human‐disturbed areas. Identifying the nature of density effects can have a direct application to these conservation methods.…”

Conservation where people work: A role for business districts and industrial areas in enhancing endangered butterfly populations?

“…Natural breeding areas (sand banks, beaches) in the region have disappeared or are disturbed by recreation. For these species, gravel roofs on office buildings and large areas of derelict land within industrial zones now provide a secondary breeding habitat that is vital for species persistence (Schippers et al, 2009). Another EU Habitat Directive species, the natterjack toad (Bufo calamita), has its largest Belgium population in the Port of Antwerp.…”

Clearing islands as refugia for black-fronted tern (Chlidonias albostriatus) breeding colonies in braided rivers

“…We present some evidence that cleared islands can provide habitat that is safe from flooding and have lower mammalian predation pressure. Artificially creating habitat to mimic natural habitat can play a critical role in population recovery of terns (Schippers et al 2009;Pakanen et al 2014). We recommend that the possible effects of avian predators and potential specialisation be considered (Sanz-Aguilar et al 2009) and monitoring of black-fronted terns on lowland rivers be continued, extending it to include different life-stages, on cleared and vegetated islands.…”