The conservation status and population decline of the African penguin deconstructed in space and time

Sherley, Richard B.; Crawford, Robert J. M.; Blocq, Andrew D. de; Dyer, Bruce M.; Geldenhuys, Deon; Hagen, Christina; Kemper, Jessica; Makhado, Azwianewi B.; Pichegru, Lorien; Tom, Desmond; Upfold, Leshia; Visagie, J; Waller, Lauren J.; Winker, Henning

doi:10.1002/ece3.6554

Cited by 41 publications

(22 citation statements)

References 52 publications

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“…Stony Point is one of the five main African Penguin breeding colonies in the Western Cape, along with Dassen Island, Robben Island, Simon's Town (Boulders Beach) and Dyer Island. Nowadays, the colony supports more than 1700 breeding pairs and is considered a site of national as well as international significance for the conservation of this species (Sherley et al 2020).…”

Section: Study Site and Acoustic Recordingsmentioning

confidence: 99%

Passive acoustic monitoring of the endangered African Penguin (Spheniscus demersus) using autonomous recording units and ecoacoustic indices

Favaro

Cresta

Friard

et al. 2021

Ibis

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African Penguins Spheniscus demersus are endangered and declining seabirds which make extensive use of vocal signals for intra-specific vocal communication. Accordingly, passive acoustic monitoring tools could be developed as robust population monitoring methods that cause minimal disturbance to the birds. In this study, we collected soundscape recordings at the Stony Point penguin colony (Betty's Bay, South Africa) during the breeding season in 2019 to document the circadian rhythms of vocal activity of this species and to investigate whether the magnitude of variation of three different ecoacoustic indices correlates with the number of ecstatic and mutual display songs counted in recordings, which might inform on the breeding activity of the colony. Indeed, whereas ecstatic display songs are produced by males during intersexual competition and territorial defence, mutual display songs are given by parents returning to the nest after foraging trips. We found that the vast majority of the display songs (> 80%) occurred between 04:00-08:00 and 17:30-21:30 h. We also found that the Acoustic Entropy Index was a good predictor of the number of penguins' songs within a recording. Overall, our study shows that African Penguins vocalizations have the potential to assist the monitoring of this species while minimizing disturbance.

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Section: Study Site and Acoustic Recordingsmentioning

confidence: 99%

Passive acoustic monitoring of the endangered African Penguin (Spheniscus demersus) using autonomous recording units and ecoacoustic indices

Favaro

Cresta

Friard

et al. 2021

Ibis

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“…The Stony Point African penguin colony (34.3741° S, 18.8917° E) is located next to a residential area in Betty’s Bay, South Africa. The site was first colonized by the African penguin in 1982, becoming one of the largest breeding colonies in South Africa ( Sherley et al, 2020 ; Underhill et al, 2006 ). The colony is a popular ecotourist attraction, with an average of 75 000 visitors annually (CapeNature, unpubl.…”

Section: Methodsmentioning

confidence: 99%

“…As such, conservation efforts of all penguin species are of utmost importance ( Ropert-Coudert et al, 2019 ). Although once abundant throughout its natural range, population sizes have decreased by 72% from 63 000 to ~ 17 000 breeding pairs in the 40 years between 1979 and 2019 ( Sherley et al, 2020 ). As a result, the species is classified as Endangered by the International Union for Conservation of Nature ( Birdlife International, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

Urofaecal glucocorticoid metabolite concentrations in African penguin (Spheniscus demersus) chick populations experiencing different levels of human disturbance

Scheun

Miller

Ganswindt

et al. 2021

Conservation Physiology

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Despite the importance of ecotourism in species conservation, little is known about the industry’s effects on wildlife. In South Africa, some African penguin (Spheniscus demersus) colonies have become tourist attractions. The species is globally endangered, with population sizes decreasing over the past 40 years. As African penguin chicks are altricial and unable to move away from anthropogenic stressors, it is important to evaluate the effect of tourist activities on baseline glucocorticoid levels as a measure of potential disturbance. Chicks at three study sites within two breeding colonies (Robben Island, Stony Point), with varying levels of exposure to tourism (low/moderate/high) were monitored. Urofaecal samples were collected to determine urofaecal glucocorticoid metabolite (ufGCM) concentrations as an indication of baseline stress physiology. Morphometric measurements were taken to compare body condition between sites. Penguin chicks experiencing low, infrequent human presence had significantly higher mean (± standard deviation) ufGCM levels [1.34 ± 1.70 μg/g dry weight (DW)] compared to chicks experiencing both medium (0.50 ± 0.40 μg/g DW, P = 0.001) and high levels of human presence (0.57 ± 0.47 μg/g DW, P = 0.003). There was no difference in chick body condition across sites. These results suggest that exposure to frequent human activity may induce habituation/desensitization in African penguin chicks. Acute, infrequent human presence was likely an important driver for comparatively higher ufGCM levels in chicks, though several other environmental stressors may also play an important role in driving adrenocortical activity. Nevertheless, as unhabituated chicks experiencing infrequent anthropogenic presence showed significantly higher ufGCM levels, managers and legislation should attempt to minimize all forms of activity around important breeding colonies that are not already exposed to regular tourism. Although the results of this study are crucial for developing enhanced conservation and management protocols, additional research on the long-term effect of anthropogenic activities on African penguin physiology is required.

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“…Extinction risk is often established based on population abundance change, which can be spatially variable Sherley et al (2020) use 40 years of count data of African penguin (Spheniscus demersus) and model spatially dependent abundance change through time to identify regions in the geographic range at high risk of extinction. The overall decline in abundance was 65% since 1989, indicating that the threshold for the IUCN 'Endangered' Red List category had been crossed.…”

Section: Management Of Biodiversitymentioning

confidence: 99%

A quantitative review of abundance-based species distribution models

Waldock

Stuart‐Smith

Albouy

et al. 2021

Preprint

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The contributions of species to ecosystem functions or services depend not only on their presence in a given community, but also on their local abundance. Progress in predictive spatial modelling has largely focused on species occurrence, rather than abundance. As such, limited guidance exists on the most reliable methods to explain and predict spatial variation in abundance. We analysed the performance of 68 abundance-based species distribution models fitted to 800,000 standardised abundance records for more than 800 terrestrial bird and reef fish species. We found high heterogeneity in performance of abundance-based models. While many models performed poorly, a subset of models consistently reconstructed range-wide abundance patterns. The best predictions were obtained using random forests for frequently encountered and abundant species, and for predictions within the same environmental domain as model calibration. Extending predictions of species abundance outside of the environmental conditions used in model training generated poor predictions. Thus, interpolation of abundances between observations can help improve understanding of spatial abundance patterns, but extrapolated predictions of abundance, e.g. under climate change, have a much greater uncertainty. Our synthesis provides a roadmap for modelling abundance patterns, a key property of species' distributions that underpins theoretical and applied questions in ecology and conservation.

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The conservation status and population decline of the African penguin deconstructed in space and time

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 41 publications

References 52 publications

Passive acoustic monitoring of the endangered African Penguin (Spheniscus demersus) using autonomous recording units and ecoacoustic indices

Passive acoustic monitoring of the endangered African Penguin (Spheniscus demersus) using autonomous recording units and ecoacoustic indices

Urofaecal glucocorticoid metabolite concentrations in African penguin (Spheniscus demersus) chick populations experiencing different levels of human disturbance

A quantitative review of abundance-based species distribution models

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