Collapse of breeding success in desert-dwelling hornbills evident within a single decade

dc.contributor.authorPattinson, N.B. (Nicholas)
dc.contributor.authorvan de Ven, Tanja M. F. N.
dc.contributor.authorFinnie, Mike J.
dc.contributor.authorNupen, Lisa J.
dc.contributor.authorMcKechnie, Andrew E.
dc.contributor.authorCunningham, Susan J.
dc.date.accessioned2022-07-25T09:53:21Z
dc.date.available2022-07-25T09:53:21Z
dc.date.issued2022-05-19
dc.description.abstractRapid anthropogenic climate change potentially severely reduces avian breeding success. While the consequences of high temperatures and drought are reasonably well-studied within single breeding seasons, their impacts over decadal time scales are less clear. We assessed the effects of air temperature (Tair) and drought on the breeding output of southern yellow-billed hornbills (Tockus leucomelas; hornbills) in the Kalahari Desert over a decade (2008–2019). We aimed to document trends in breeding performance in an arid-zone bird during a time of rapid global warming and identify potential drivers of variation in breeding performance. The breeding output of our study population collapsed during the monitoring period. Comparing the first three seasons (2008–2011) of monitoring to the last three seasons (2016–2019), the mean percentage of nest boxes that were occupied declined from 52% to 12%, nest success from 58% to 17%, and mean fledglings produced per breeding attempt from 1.1 to 0.4. Breeding output was negatively correlated with increasing days on which Tmax (mean maximum daily Tair) exceeded the threshold Tair at which male hornbills show a 50% likelihood of engaging in heat dissipation behavior [i.e., panting (Tthresh; Tair = 34.5◦C)] and the occurrence of drought within the breeding season, as well as later dates for entry into the nest cavity (i.e., nest initiation) and fewer days post-hatch, spent incarcerated in the nest by the female parent. The apparent effects of high Tair were present even in non-drought years; of the 115 breeding attempts that were recorded, all 18 attempts that had ≥ 72% days during the attempt on which Tmax > Tthresh failed (equivalent to Tmax during the attempt ≥ 35.7◦C). This suggests that global warming was likely the primary driver of the recent, rapid breeding success collapse. Based on current warming trends, the Tmax threshold of 35.7◦C, above which no successful breeding attempts were recorded, will be exceeded during the entire hornbill breeding season by approximately 2027 at our study site. Therefore, our findings support the prediction that climate change may drive rapid declines and cause local extinctions despite the absence of direct lethal effects of extreme heat events.en_US
dc.description.departmentZoology and Entomologyen_US
dc.description.librariandm2022en_US
dc.description.sponsorshipThe DST-NRF Center of Excellence at the FitzPatrick Institute, Natural Environment Research Council, and the National Research Foundation of South Africa.en_US
dc.description.urihttp://frontiersin.org/Ecology_and_Evolutionen_US
dc.identifier.citationPattinson, N.B., Van de Ven, T.M.F.N., Finnie, M.J., Nupen, L.J., McKechnie, A.E. & Cunningham, S.J. (2022) Collapse of Breeding Success in Desert-Dwelling Hornbills Evident Within a Single Decade. Frontiers in Ecology and Evolution 10:842264. doi: 10.3389/fevo.2022.842264.en_US
dc.identifier.issn2296-701X (online)
dc.identifier.other10.3389/fevo.2022.842264
dc.identifier.urihttps://repository.up.ac.za/handle/2263/86427
dc.language.isoenen_US
dc.publisherFrontiers Media S.A.en_US
dc.rights© 2022 Pattinson, van de Ven, Finnie, Nupen, McKechnie and Cunningham. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).en_US
dc.subjectHigh temperaturesen_US
dc.subjectDroughten_US
dc.subjectBreedingen_US
dc.subjectClimate changeen_US
dc.subjectArid-zone birden_US
dc.subjectSouthern yellow-billed hornbills (Tockus leucomelas)en_US
dc.titleCollapse of breeding success in desert-dwelling hornbills evident within a single decadeen_US
dc.typeArticleen_US

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