African Penguins Spheniscus demersus in South Africa occur in two populations separated by 600 km of coastline lacking secure island breeding sites. Climate-induced shifts in fish stocks are partly responsible for dramatic declines in penguin numbers in western colonies. Plans are underway to create a new mainland colony between the two populations to increase the species’ resilience to further climate change impacts and other threats. This will involve protection from predators, provision of nest boxes, deployment of decoys, and translocation of juveniles.
Improving connectivity among key sites will be important in enabling species persistence in light of climate change. In some cases, targeted intervention may be needed, such as captive breeding and assisted colonisation (Hoegh-Guldberg et al. 2008). This is an approach more commonly utilised for invertebrates such as butterflies in fragmented landscapes (Willis et al. 2009), and is less frequently considered for vertebrates such as the African Penguin Spheniscus demersus.
South Africa’s two African Penguin populations are separated by 600km of coastline, lacking the islands penguins may usually populate. Both populations have experienced declines; the eastern population declining by 52% to 10,000 pairs in 2003, and the Western population declining by 69% from 35,000 pairs in 2001-2005 to 11,000 pairs in 2009 (Crawford et al. 2011).
African Penguins are central place foragers, travelling only short distances from the colony for their prey (Pichegru et al. 2009). For chick rearing, prey availability near the breeding colony is an important determinant of breeding success (Sherley et al. 2013). Changes in population sizes therefore seem to be largely driven by food availability, which is thought to be likely influenced by climate change. There has been a recent shift in the distribution of sardine—an important prey item for African Penguins—to the east (Fairweather et al. 2006, Crawford et al. 2008), with western colonies suffering more than eastern colonies (Crawford et al. 2008). Further climate-induced changes in prey distribution are likely to influence penguin persistence, alongside other threats such purse-seine fishing (Pichegru et al. 2012).
Birdlife South Africa is acting to increase the resilience of its existing penguin populations through the creation of a new mainland colony in the 600km stretch of coast between the west and east populations. Feasibility studies will be a vital process in the selection of potential sites, including the monitoring of fish populations to ensure adequate food supplies. Before the translocation of juvenile penguins takes place, predator exclusion fences and nest boxes will be installed, as well as the deployment of decoys and sound devices to give an illusion of inhabitation.
This case study is taken from ‘The Messengers: What birds tell us about threats from climate change and solutions for nature and people’. To download the report in full click here.
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Compiled: 2015 Copyright: 2015
BirdLife International (2015) Assisted colonisation will help African Penguin populations impacted by climate change. Downloaded from http://www.birdlife.org on 15/11/2019