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The Vertebrate Fauna of Jenolan Karst Conservation Reserve: Final

The Vertebrate Fauna of Jenolan Karst Conservation Reserve: Final

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EASTERN BENTWING-BAT MINIOPTERUS SCHREIBERSII OCEANENSIS<br />

EPBC Act: Not Listed TSC Act: Vulnerable Priority in area: High<br />

Eastern bentwing-bat. Photo © M. Schulz<br />

Eastern bentwing-bats roosting. Photo © N.<br />

Williams<br />

Occurrence in the Survey Area<br />

Common resident with regionally important roosting sites.<br />

This species has recently been revised to M. orianae<br />

oceanensis although it still appears on the NSW and<br />

Commonwealth legislative schedules under its former<br />

name therefore this nomenclature has been retained for<br />

this document. <strong>The</strong> karst system at JKCR provides a wide<br />

diversity <strong>of</strong> caves, overhangs and other features that this<br />

species uses to roost. It is found throughout JKCR<br />

including: Mammoth Flat, Blue Lake, <strong>Jenolan</strong> River<br />

Campsite, McKeowns Valley, Binda Bush cottages,<br />

<strong>Jenolan</strong> River (near Stockyard Creek), <strong>Jenolan</strong> River Trail<br />

dam, the Info Bay trail, Oaky Camp trail (at gate), the<br />

Devil’s Coach House and Surveyors Creek weir. <strong>The</strong> 2011<br />

surveys recorded a large number <strong>of</strong> eastern bentwing-bats<br />

(~1000) in the ‘southern limestone’ area (Paradox Cave).<br />

Approximately 50 animals were also observed within<br />

Mammoth Cave; however guides indicate that numbers<br />

tend to be higher in August and September. Mammoth<br />

Cave may not be used all year around, with researchers<br />

previously recording an absence <strong>of</strong> eastern bentwing-bats<br />

in June (Euston et al. 2009). Due to the extensive area <strong>of</strong><br />

karst, it is likely that further sizable roosts occur<br />

unrecorded within JKCR.<br />

This survey found colonies <strong>of</strong> eastern bentwing-bats at<br />

JKCR to be temporally segregated based on age and/or sex, which is typical <strong>of</strong> the species (Dwyer<br />

1966). No evidence <strong>of</strong> a maternity roost was found during this or previous surveys. It is still possible<br />

that a large maternity roost is present, though this seems increasingly unlikely. No bats captured<br />

during this study showed evidence <strong>of</strong> lactation, although the sample size was relatively low, and the<br />

survey later than ideal. During the maternity period the population at Paradox Cave was male biased<br />

and all females captured were non-reproductive. It is not known if JKCR historically supported a<br />

maternity roost, though Tear Drop Cave has been highlighted as a former maternity cave (E. Holland<br />

pers. comm. to A. Spate). Due to the extensive nature<br />

<strong>of</strong> the cave system at <strong>Jenolan</strong>, it is likely that some<br />

part may have once been suitable. However, early<br />

cave management practices tended to be insensitive<br />

and would have impacted this species.<br />

Ideal maternity sites are thought to require high domed<br />

ceilings, small low entrance passageways, the<br />

propensity to trap metabolic heat released from<br />

roosting bats (Hall and Richards 2003) and a stable<br />

temperature <strong>of</strong> 20-29 degrees centigrade (Dwyer<br />

1963, 1971). None <strong>of</strong> the caves visited during this<br />

survey fulfil these requirements, though Paradox Cave<br />

is thought to be the most suitable. However, this bat is<br />

also known to breed in smaller caves and artificial sites<br />

(Hoye 2000 and R. Williams pers. comm.) meaning<br />

smaller sites remain a possibility at <strong>Jenolan</strong>. Banding<br />

data shows bats from <strong>Jenolan</strong> have moved to or from<br />

maternity sites at Wee Jasper, Bungonia and mine<br />

adits in the Warragamba catchment (P. Wilson pers.<br />

comm.). Elsewhere in NSW maternity sites occur at<br />

Willi Willi caves and Nimbin (Hall and Richards 2003)<br />

and in a mine in the Hunter Valley (Hoye 2000).<br />

Seasonal movements <strong>of</strong> eastern bentwing-bats are<br />

<strong>The</strong> <strong>Vertebrate</strong> <strong>Fauna</strong> <strong>of</strong> <strong>Jenolan</strong> <strong>Karst</strong> <strong>Conservation</strong> <strong>Reserve</strong> 77

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