Outbreak of avian botulism and its effect on waterbirds in the Wilderness Lakes, South Africa
Avian botulism has been reported in many areas worldwide, particularly in North America, where at times it has resulted in die-offs of hundreds of thousands of waterbirds. By contrast, there are few reported cases in wild waterbird communities in South Africa. Mass die-offs of waterbirds in the Wild...
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ftdoajarticles:oai:doaj.org/article:af7d92bb81f543e4b160bca311c03b96 2023-05-15T18:19:23+02:00 Outbreak of avian botulism and its effect on waterbirds in the Wilderness Lakes, South Africa Ian A. Russell Rodney M. Randall David Zimmerman Danny Govender 2019-10-01T00:00:00Z https://doi.org/10.4102/koedoe.v61i1.1553 https://doaj.org/article/af7d92bb81f543e4b160bca311c03b96 EN eng AOSIS https://koedoe.co.za/index.php/koedoe/article/view/1553 https://doaj.org/toc/0075-6458 https://doaj.org/toc/2071-0771 0075-6458 2071-0771 doi:10.4102/koedoe.v61i1.1553 https://doaj.org/article/af7d92bb81f543e4b160bca311c03b96 Koedoe: African Protected Area Conservation and Science, Vol 61, Iss 1, Pp e1-e13 (2019) botulism disease wetlands waterbirds ramsar wilderness lakes General. Including nature conservation geographical distribution QH1-199.5 article 2019 ftdoajarticles https://doi.org/10.4102/koedoe.v61i1.1553 2022-12-31T12:20:33Z Avian botulism has been reported in many areas worldwide, particularly in North America, where at times it has resulted in die-offs of hundreds of thousands of waterbirds. By contrast, there are few reported cases in wild waterbird communities in South Africa. Mass die-offs of waterbirds in the Wilderness Lakes, South Africa, were first observed in January 2015, raising concerns about the effect of disease on the status of waterbird communities in this Ramsar site. Surveys of bird carcasses were undertaken between 2015 and 2017. An estimated 1115 individuals from 23 species were affected, with sick individuals displaying symptoms of avian type C, C and D or E botulism. The highest mortality was amongst red-knobbed coot (Fulica cristata), Cape shoveler (Anas smithii) and yellow-billed duck (Anas undulata), respectively comprising 60%, 18% and 9% of affected individuals. Cape shoveler was found to be particularly susceptible to the disease. Deaths occurred mainly during summer and autumn (November–April). No mortalities were recorded amongst 44 waterbird species, of which common moorhen (Gallinula choropus), African purple swamphen (Porphyrio madagascariensis) and reed cormorant (Phalacrocorax africanus) are widespread and abundant. The reasons for the outbreaks remain elusive, as environmental changes characteristic of a botulism outbreak, notably a decline in water level and dissolved oxygen, did not differ substantially from earlier years when no disease outbreaks were observed. The role of fish, and in particular the recently introduced common carp (Cyprinus carpio) in the progression of the disease, remains speculative, although worthy of investigation. The removal of carcasses for disease control should be continued. Conservation implications: The long-term effect of repeated outbreaks of avian botulism on the abundance of susceptible waterbird species in the Wilderness Lakes is of concern. The previous regular high abundance of duck species, particularly yellow-billed duck and Cape shoveler, was the initial ... Article in Journal/Newspaper Shoveler Directory of Open Access Journals: DOAJ Articles KOEDOE - African Protected Area Conservation and Science 61 1 |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
botulism disease wetlands waterbirds ramsar wilderness lakes General. Including nature conservation geographical distribution QH1-199.5 |
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botulism disease wetlands waterbirds ramsar wilderness lakes General. Including nature conservation geographical distribution QH1-199.5 Ian A. Russell Rodney M. Randall David Zimmerman Danny Govender Outbreak of avian botulism and its effect on waterbirds in the Wilderness Lakes, South Africa |
topic_facet |
botulism disease wetlands waterbirds ramsar wilderness lakes General. Including nature conservation geographical distribution QH1-199.5 |
description |
Avian botulism has been reported in many areas worldwide, particularly in North America, where at times it has resulted in die-offs of hundreds of thousands of waterbirds. By contrast, there are few reported cases in wild waterbird communities in South Africa. Mass die-offs of waterbirds in the Wilderness Lakes, South Africa, were first observed in January 2015, raising concerns about the effect of disease on the status of waterbird communities in this Ramsar site. Surveys of bird carcasses were undertaken between 2015 and 2017. An estimated 1115 individuals from 23 species were affected, with sick individuals displaying symptoms of avian type C, C and D or E botulism. The highest mortality was amongst red-knobbed coot (Fulica cristata), Cape shoveler (Anas smithii) and yellow-billed duck (Anas undulata), respectively comprising 60%, 18% and 9% of affected individuals. Cape shoveler was found to be particularly susceptible to the disease. Deaths occurred mainly during summer and autumn (November–April). No mortalities were recorded amongst 44 waterbird species, of which common moorhen (Gallinula choropus), African purple swamphen (Porphyrio madagascariensis) and reed cormorant (Phalacrocorax africanus) are widespread and abundant. The reasons for the outbreaks remain elusive, as environmental changes characteristic of a botulism outbreak, notably a decline in water level and dissolved oxygen, did not differ substantially from earlier years when no disease outbreaks were observed. The role of fish, and in particular the recently introduced common carp (Cyprinus carpio) in the progression of the disease, remains speculative, although worthy of investigation. The removal of carcasses for disease control should be continued. Conservation implications: The long-term effect of repeated outbreaks of avian botulism on the abundance of susceptible waterbird species in the Wilderness Lakes is of concern. The previous regular high abundance of duck species, particularly yellow-billed duck and Cape shoveler, was the initial ... |
format |
Article in Journal/Newspaper |
author |
Ian A. Russell Rodney M. Randall David Zimmerman Danny Govender |
author_facet |
Ian A. Russell Rodney M. Randall David Zimmerman Danny Govender |
author_sort |
Ian A. Russell |
title |
Outbreak of avian botulism and its effect on waterbirds in the Wilderness Lakes, South Africa |
title_short |
Outbreak of avian botulism and its effect on waterbirds in the Wilderness Lakes, South Africa |
title_full |
Outbreak of avian botulism and its effect on waterbirds in the Wilderness Lakes, South Africa |
title_fullStr |
Outbreak of avian botulism and its effect on waterbirds in the Wilderness Lakes, South Africa |
title_full_unstemmed |
Outbreak of avian botulism and its effect on waterbirds in the Wilderness Lakes, South Africa |
title_sort |
outbreak of avian botulism and its effect on waterbirds in the wilderness lakes, south africa |
publisher |
AOSIS |
publishDate |
2019 |
url |
https://doi.org/10.4102/koedoe.v61i1.1553 https://doaj.org/article/af7d92bb81f543e4b160bca311c03b96 |
genre |
Shoveler |
genre_facet |
Shoveler |
op_source |
Koedoe: African Protected Area Conservation and Science, Vol 61, Iss 1, Pp e1-e13 (2019) |
op_relation |
https://koedoe.co.za/index.php/koedoe/article/view/1553 https://doaj.org/toc/0075-6458 https://doaj.org/toc/2071-0771 0075-6458 2071-0771 doi:10.4102/koedoe.v61i1.1553 https://doaj.org/article/af7d92bb81f543e4b160bca311c03b96 |
op_doi |
https://doi.org/10.4102/koedoe.v61i1.1553 |
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KOEDOE - African Protected Area Conservation and Science |
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61 |
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