Mitochondrial phylogeography of the critically endangered Capricorn yellow chat (Epthianura crocea macgregori)

Houston, Wayne; Aspden, William J.; Black, Robert L.; Elder, R. J.; Carruthers, Ian; Campbell, Lorelle; Black, Leif

doi:10.1071/zo15047

Cited by 7 publications

(23 citation statements)

References 19 publications

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“…It has been recorded at 15 sites but only regularly at five locations, including Torilla Plain, where it is most abundant (Garnett et al, 2011). The subspecies was once believed to be extinct but was rediscovered on the marine plain on Curtis Island in 1992, having not been seen for 70 years (Houston et al, 2004; FBA, 2007). It was first listed as Critically Endangered in 2000 on the basis that the habitat of this single population was thought to be decreasing in area and quality.…”

Section: Resultsmentioning

confidence: 99%

Do social values influence levels of conservation effort in threatened species? The case of two Australian chats

Ainsworth

Aslin

Weston

et al. 2015

Oryx

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This research aims to understand why one of two almost identical subspecies of the Australian yellow chat Ephthianura crocea has received significantly higher levels of local and institutional support than the other despite both having the same conservation status and taxonomic distinctiveness, factors commonly thought to influence conservation effort. Using a qualitative multiple case study approach we explored how a range of social factors, including stakeholder attitudes and institutional, policy and operational aspects, might have affected conservation efforts for the two taxa. Our results suggest that the conservation trajectories of these two subspecies have diverged since their identification as threatened species in  because of differences in the social landscapes within which they persist. For one subspecies local advocacy was kindled initially by the small number of local endemic bird species but developed into a strong emotional engagement, resulting in increased local awareness, government funding, and effectiveness of conservation action. The other subspecies has had to compete for attention with approximately  other threatened taxa occurring in its region. No individual advocate has accorded this subspecies a high priority for action, and none of those responsible for its conservation have seen it or acknowledged an emotional attachment to it. Our findings confirm that initiation of conservation effort is strongly tied to the social values of individuals with power to take action, regardless of legislation.

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Section: Resultsmentioning

confidence: 99%

Do social values influence levels of conservation effort in threatened species? The case of two Australian chats

Ainsworth

Aslin

Weston

et al. 2015

Oryx

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“…Patterns of rainfall deficits over the 2000–2009 period were similar in all three areas where CYCs occur. However, while chats persisted at Broad Sound and the Fitzroy River delta, they declined substantially at Curtis Island from around 30 in 2002 to only four adults in 2008 and none in 2009 (Houston et al 2004b, W. Houston unpubl. data).…”

Section: Discussionmentioning

confidence: 99%

“…However, in 1992 the subspecies was rediscovered when a small subpopulation of less than 50 birds was found on the marine plain in the north-east part of Curtis Island, east of the Fitzroy River mouth (Arnold et al 1993). Subsequently, its historical range was re-established and the probable reason why it has not been detected determined (Jaensch et al 2004, Houston et al 2004a, 2004b, 2013). The CYC occurs in small, seldom-visited, difficult-to-access fragments of suitable habitat totalling less than 7,000 ha in three main areas (north at Broad Sound, south in the Fitzroy River delta and south-east at Curtis Island; Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Population trend and conservation status of the Capricorn Yellow Chat Epthianura crocea macgregori

Houston

Elder

Black

2017

Bird Conservation International

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SummaryThe average population size of Capricorn Yellow Chat Epthianura crocea macgregori was estimated at 251 +/-31 (SE) by repeated surveys over seven years (2004–2010) using consistent search effort at known occupied sites. Because the survey period coincided with a mixture of dry and wet years (drought from 2004 to 2007 followed by flood rainfall in early 2008 and 2010), it is particularly valuable as a preliminary benchmark upon which to base management decisions. Most of the population (74.5%) was in the Broad Sound area in the north, with lower numbers in the Fitzroy River delta area in the south (22%) and at Curtis Island (3.5%). Sites on Torilla Plain in Broad Sound accounted for two-thirds of the estimated population, making it a priority for conservation efforts. Depending on habitat configuration, some Capricorn Yellow Chats showed a seasonal pattern of habitat use, moving from flooded breeding habitats as they dried to refuge sites such as salt fields or upper marine plains in the dry season; distances moved being < 10 km. Standard surveys from Torilla Plain showed that the chat count during a sequence of above-average rainfall years was almost double that of the average for drought years: 162 +/-28 (2008–2015) compared with 85 +/-15 (2004–2007) respectively. Low population size, large annual fluctuations in population with prior rainfall, rapid declines in low rainfall years, a fragmented distribution and almost half the population concentrated at one site point to a subspecies vulnerable to chance events. Increased climatic extremes predicted by climate change such as higher temperatures, evaporation rates, extended droughts and more intense rainfall events add to its vulnerability.

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“…Although there are slight morphological differences, a recent study of mitochondrial DNA found no genetic diversity within, nor genetic divergence between, Capricorn Yellow Chats occupying the two areas at the northern and southern extremes of the distribution (Houston et al 2015).…”

Section: Introductionmentioning

confidence: 91%

“…During glacial maxima, sea levels were much lower and the associated marine plains were much greater in area, connecting the two areas. Further, the climate was more arid and the type of wetlands supporting Capricorn Yellow Chats were likely to be more extensive, expanding out along the current continental shelf and increasing the likelihood that the two populations were interconnected (Houston et al 2015). Subsequent sea level rises some 7,000 years ago (Brooke et al 2006) then isolated them.…”

Section: Southern (N = 7)mentioning

confidence: 99%

Restricted gene flow in the endangered Capricorn Yellow ChatEpthianura crocea macgregori: consequences for conservation management

Houston

Aspden

Elder

et al. 2017

Bird Conservation International

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SummaryThe Yellow Chat Epthianura crocea is comprised of three disjunct subspecies. Subspecies E. c. macgregori (Capricorn Yellow Chat) is listed as Critically Endangered under the EPBC Act and has a distribution that also appears to be disjunct, with a limited geographic area of less than 7,000 ha. Some populations are threatened by rapid industrial development, and it is important for conservation of the subspecies to determine the extent to which the putative populations are connected. We used 14 microsatellite markers to measure genetic diversity and to determine the extent of gene flow between two disjunct populations at the northern and southern extremes of the subspecies’ range. No significant differences in genetic diversity (number of alleles and heterozygosity) were observed, but clear population structuring was apparent, with obvious differentiation between the northern and southern populations. The most likely explanation for reduced gene flow between the two populations is either the development of a geographic barrier as a consequence of shrinkage of the marine plains associated with the rise in sea levels following the last glacial maxima, or reduced connectivity across the largely unsuitable pasture and forest habitat that now separates the two populations, exacerbated by declining population size and fewer potential emigrants. Regardless of the mechanism, restricted gene flow between these two populations has important consequences for their ongoing conservation. The relative isolation of the smaller southern groups (the Fitzroy River delta and Curtis Island) from the much larger northern group (both sides of the Broad Sound) makes the southern population more vulnerable to local extinction. Conservation efforts should focus on nature refuge agreements with land owners agreeing to maintain favourable grazing management practices in perpetuity, particularly in the northern area where most chats occur. Supplemental exchanges of individuals from northern and southern populations should be explored as a way of increasing genetic diversity and reducing inbreeding.

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Mitochondrial phylogeography of the critically endangered Capricorn yellow chat (Epthianura crocea macgregori)

Cited by 7 publications

References 19 publications

Do social values influence levels of conservation effort in threatened species? The case of two Australian chats

Do social values influence levels of conservation effort in threatened species? The case of two Australian chats

Population trend and conservation status of the Capricorn Yellow Chat Epthianura crocea macgregori

Restricted gene flow in the endangered Capricorn Yellow ChatEpthianura crocea macgregori: consequences for conservation management

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