The conservation status and population decline of the African penguin deconstructed in space and time
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Date
2020
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley-Blackwell
Abstract
Understanding changes in abundance is crucial for conservation, but population growth rates often vary over space and time. We use 40 years of count data (1979–2019) and Bayesian state-space models to assess the African penguin Spheniscus demersus population under IUCN Red List Criterion A. We deconstruct the overall decline in time and space to identify where urgent conservation action is needed. The global African penguin population met the threshold for Endangered with a high probability (97%), having declined by almost 65% since 1989. An historical low of ~17,700 pairs bred in 2019. Annual changes were faster in the South African population (−4.2%, highest posterior density interval, HPDI: −7.8 to −0.6%) than the Namibian one (−0.3%, HPDI: −3.3 to +2.6%), and since 1999 were almost −10% at South African colonies north of Cape Town. Over the 40-year period, the Eastern Cape colonies went from holding ~25% of the total penguin population to ~40% as numbers decreased more rapidly elsewhere. These changes coincided with an altered abundance and availability of the main prey of African penguins. Our results underline the dynamic nature of population declines in space as well as time and highlight which penguin colonies require urgent conservation attention.
Description
Keywords
Bayesian state-space model, Benguela ecosystem, Extinction risk, IUCN red list assessment, Population dynamics
Citation
Waller, L. J. et al. (2020). The conservation status and population decline of the African penguin deconstructed in space and time. Ecology and Evolution ,10(15), 8506-8516