Modelling urban populations of the Australian White Ibis (Threskiornis molucca) to inform management

Smith, ACM; Munro, U; Figueira, WF

Modelling urban populations of the Australian White Ibis (Threskiornis molucca) to inform management

Smith, ACM Munro, U Figueira, WF

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Publication Type:: Journal Article
Citation:: Population Ecology, 2013, 55 (4), pp. 567 - 574
Issue Date:: 2013-07-02

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Field	Value	Language
dc.contributor.author	Smith, ACM	en_US
dc.contributor.author	Munro, U	en_US
dc.contributor.author	Figueira, WF https://orcid.org/0000-0001-9472-8710	en_US
dc.date.issued	2013-07-02	en_US
dc.identifier.citation	Population Ecology, 2013, 55 (4), pp. 567 - 574	en_US
dc.identifier.issn	1438-3896	en_US
dc.identifier.uri	http://hdl.handle.net/10453/27118
dc.description.abstract	Since the 1970s, populations of the Australian White Ibis (Threskiornis molucca) have dramatically increased in many Australian urban centres. Managers of ibis are currently focusing on limiting this bird's reproductive success in order to reduce population sizes or at least halt further increases in urban areas. Here we use data on nesting success and survival for three populations of ibis around greater Sydney to develop an age-structured population model. The estimated growth rate for all populations combined was about 1.5 % per year and for individual sites were more variable at -1, -7, and 9 %. For all populations, growth rates were most sensitive (based on elasticity analyses) to the survival of adults and least sensitive to fecundity, especially of 3 year olds. Further exploration of the importance of fecundity rates, which are relatively poorly known for these populations, suggests that rates of <0.4 fledglings per nest per year is very likely to lead to a population decline (λ less than lower bound of 95 % CI). Conversely, positive population growth is nearly assured (λ greater than upper bound of 95 % CI) for fecundities of >0.7 fledgling per nest per year. The results suggest that ibis from other locations (probably their traditional breeding areas in inland Australia) have immigrated into urban environments as estimated growth rates cannot account for current population sizes. Management strategies must take these findings into account and also consider that ibis are declining in their traditional habitats to avoid exacerbating their decline at a regional scale. © 2013 The Society of Population Ecology and Springer Japan.	en_US
dc.relation.ispartof	Population Ecology	en_US
dc.relation.isbasedon	10.1007/s10144-013-0385-2	en_US
dc.subject.classification	Ecology	en_US
dc.title	Modelling urban populations of the Australian White Ibis (Threskiornis molucca) to inform management	en_US
dc.type	Journal Article
utslib.citation.volume	4	en_US
utslib.citation.volume	55	en_US
utslib.for	0602 Ecology	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of the Environment
utslib.copyright.status	closed_access
pubs.issue	4	en_US
pubs.publication-status	Published	en_US
pubs.volume	55	en_US

Abstract:

Since the 1970s, populations of the Australian White Ibis (Threskiornis molucca) have dramatically increased in many Australian urban centres. Managers of ibis are currently focusing on limiting this bird's reproductive success in order to reduce population sizes or at least halt further increases in urban areas. Here we use data on nesting success and survival for three populations of ibis around greater Sydney to develop an age-structured population model. The estimated growth rate for all populations combined was about 1.5 % per year and for individual sites were more variable at -1, -7, and 9 %. For all populations, growth rates were most sensitive (based on elasticity analyses) to the survival of adults and least sensitive to fecundity, especially of 3 year olds. Further exploration of the importance of fecundity rates, which are relatively poorly known for these populations, suggests that rates of <0.4 fledglings per nest per year is very likely to lead to a population decline (λ less than lower bound of 95 % CI). Conversely, positive population growth is nearly assured (λ greater than upper bound of 95 % CI) for fecundities of >0.7 fledgling per nest per year. The results suggest that ibis from other locations (probably their traditional breeding areas in inland Australia) have immigrated into urban environments as estimated growth rates cannot account for current population sizes. Management strategies must take these findings into account and also consider that ibis are declining in their traditional habitats to avoid exacerbating their decline at a regional scale. © 2013 The Society of Population Ecology and Springer Japan.

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http://hdl.handle.net/10453/27118