The causes of avian extinction and rarity

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dc.contributor.advisorHockey, Phil A Ren_ZA
dc.contributor.authorLennard, Christopher Jamesen_ZA
dc.date.accessioned2016-06-17T11:16:53Z
dc.date.available2016-06-17T11:16:53Z
dc.date.issued1997en_ZA
dc.descriptionBibliography: pages 144-153.en_ZA
dc.description.abstractBiological extinction rates have escalated by as much as 1000 times the background extinction rate over the last 1500 years, causing concern over the long-term survival of many species. Avian extinctions since 1600 have been well documented relative to other taxa, as have current levels of avian threat. This study analyses avian extinctions post-1600 and current threats in an attempt to develop some predictive capacity about which avian taxa should be awarded the highest conservation priority. Analyses performed include examinations of the causes of avian extinction and threat, geographical location of extinct and threatened species, prehistoric and historical extinction rates, endemicity, migration, bird body size and phylogenetic diversity. An analysis dealing with historical and phylogenetic aspects of endangered and critically threatened species was performed, from which the world's most threatened species were identified. Factors which were the primary cause of historical extinctions are generally not the primary factors threatening today's extant avifauna. Whilst introduced predators and exploitation were primary causes of historical extinctions, habitat destruction poses the greatest threat to extant birds. Species predisposed to extinction typically have restricted ranges, and, compounded by habitat loss, these ranges are becoming more restricted. This has resulted in mainland-dwelling species becoming as prone to extinction as island-dwelling species have been historically. Introduced predators, however, do still threaten many of the world's most threatened species and their potential effects are highlighted in the phylogenetic analysis. Already, many extinctions may be inevitable over the next 25 years as a result of habitat loss. The magnitude of extinctions across all animal and plant species in the next few decades could be comparable with that of previous mass extinctions unless immediate conservation action is taken. However, future conservation efforts will have to be prioritized, and this study is intended as a contribution towards such a prioritization exercise.en_ZA
dc.identifier.apacitationLennard, C. J. (1997). <i>The causes of avian extinction and rarity</i>. (Thesis). University of Cape Town ,Faculty of Science ,Percy FitzPatrick Institute of African Ornithology. Retrieved from http://hdl.handle.net/11427/20042en_ZA
dc.identifier.chicagocitationLennard, Christopher James. <i>"The causes of avian extinction and rarity."</i> Thesis., University of Cape Town ,Faculty of Science ,Percy FitzPatrick Institute of African Ornithology, 1997. http://hdl.handle.net/11427/20042en_ZA
dc.identifier.citationLennard, C. 1997. The causes of avian extinction and rarity. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Lennard, Christopher James AB - Biological extinction rates have escalated by as much as 1000 times the background extinction rate over the last 1500 years, causing concern over the long-term survival of many species. Avian extinctions since 1600 have been well documented relative to other taxa, as have current levels of avian threat. This study analyses avian extinctions post-1600 and current threats in an attempt to develop some predictive capacity about which avian taxa should be awarded the highest conservation priority. Analyses performed include examinations of the causes of avian extinction and threat, geographical location of extinct and threatened species, prehistoric and historical extinction rates, endemicity, migration, bird body size and phylogenetic diversity. An analysis dealing with historical and phylogenetic aspects of endangered and critically threatened species was performed, from which the world's most threatened species were identified. Factors which were the primary cause of historical extinctions are generally not the primary factors threatening today's extant avifauna. Whilst introduced predators and exploitation were primary causes of historical extinctions, habitat destruction poses the greatest threat to extant birds. Species predisposed to extinction typically have restricted ranges, and, compounded by habitat loss, these ranges are becoming more restricted. This has resulted in mainland-dwelling species becoming as prone to extinction as island-dwelling species have been historically. Introduced predators, however, do still threaten many of the world's most threatened species and their potential effects are highlighted in the phylogenetic analysis. Already, many extinctions may be inevitable over the next 25 years as a result of habitat loss. The magnitude of extinctions across all animal and plant species in the next few decades could be comparable with that of previous mass extinctions unless immediate conservation action is taken. However, future conservation efforts will have to be prioritized, and this study is intended as a contribution towards such a prioritization exercise. DA - 1997 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1997 T1 - The causes of avian extinction and rarity TI - The causes of avian extinction and rarity UR - http://hdl.handle.net/11427/20042 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/20042
dc.identifier.vancouvercitationLennard CJ. The causes of avian extinction and rarity. [Thesis]. University of Cape Town ,Faculty of Science ,Percy FitzPatrick Institute of African Ornithology, 1997 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/20042en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentPercy FitzPatrick Institute of African Ornithologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherOrnithologyen_ZA
dc.titleThe causes of avian extinction and rarityen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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