A Survey for the Southern Myotis Myotis Macropus (Vespertilionidae
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A survey for the Southern Myotis Myotis macropus (Vespertilionidae) and other bat species in River Red Gum Eucalyptus camaldulensis forests of the Murray River, New South Wales Bradley Law1 and Jason Andersonl~' 'Forest Research and Development Division, State Forests of NSW, PO. Box 100, Beecroft, New South Wales 2119 - Email: [email protected] 'Present Address: Anderson Ecological Surveys, 7 Hovea Place, Woodford, New South Wales 2778 ABSTRACT During March 1997 we surveyed for Myofis macmpus at 18 water bodies along the Murray Downloaded from http://meridian.allenpress.com/australian-zoologist/article-pdf/31/1/166/1474892/az_1999_016.pdf by guest on 30 September 2021 River in River Red Gum Eucalyptus camaiduiensis forests in the Millewa and Perricoota/ Koondrook State Forests, using Anabat iI detectors and harp-traps. Although no M. macropus were caught, they were recorded by Anabat detectors at two sites, one at Moira Lakes Flora Reserve and one on the Murray River at Barmah Bridge. These records were within 7 km of each other and near a previous record on the Murray River (Hoye 1995). Despite the rarity of M. macropus in these forests, high levels of microchiropteran activity from 12 other taxa were recorded. On average, one bat pass was recorded for every minute of sampling in the first hour after dark. Eight taxa (Vespadeius vuiturnus, V. regulus, V. darlingtoni, Chaiinolobus gouidii. C. morio, Mormopterus sp. and Tadarida australis) were recorded at more than 70% of sites, while four species (Scoforapens batstoni, Nyctophiius gouldi, Nyctophilus geoffroyi and Myotis macropus) were recorded from less than 40% of sites. River Red Gum forests are particularly important to bats as a mesic habitat in a predominantly semi-arid landscape. Further studies on M. macmpus are required to determine the reason for its rarity in an area with abundant surface water. Key words: Myotis macropus, River Red Gum. Murray River, Bats. INTRODUCTION River Red Gum forests, near Deniliquin. None of these broader bat surveys targeted M. The Southern Myotis Myotis macropus is listed mac~opusby concentrating survey effort on on the New South Wales Threatened Species Act water bodies. Lumsden et al. (1995) suggested 1995 by its previous name M. adversus. It is that the species may prove to be more one of only two Australian species of fishing widespread if this approach were followed. bat. It forages over pools of water in small streams, rivers and lakes, using its large feet This survey was undertaken to clarify the to trawl along water surfaces for aquatic status of M. macropus in River Red Gum insects and small fish (Dwyer 1970; Thompson forests of the Murray River near Deniliquin. and Fenton 1982; Robson 1984). It is We took a broad survey applvach to include distributed along the east coast of Australia a number of State Forests, but specifically from south-east Queensland to Victoria and targeted a range of water bodies from large South Australia. Little is known of its status rivers to ephemeral wetlands. The general in inland water systems. It was recorded west aim was to determine the distribution of of the divide in the 1970s from a billabong M. macropus in State Forests near Deniliquin at Boomanoomana State Forest, near Mulwala and to investigate whether M. mamopus was and the Murray River (B. Gall, unpubl. data). more active over certain kinds of water Jansen (1987) captured five M. macropopus in bodies. We also intended to document the monofilament mistnets set on a small creek activity levels and distribution of at least near the Murray River in South Australia 12 other microchiropteran species that could and suggested that the species may occur be expected to occur in this area as few along the full length of the river system. A bat surveys have been undertaken in western sinale capture of M. macrobus was recorded New South Wales. by Lumsden ct al. (1995) i; River Red Gum forest from 133 survey sites in a variety of -~ . METHODS vegetation types on the'northern plains region BtuaY area of Victoria. More recentlv. Hove 11995) Survevs were~- - undertaken~~---~--~~ in forest alone the 0 --- surveyed bats for State ~orestsbfN& (VjesteA ~urraiRiver, its anabranches and adjacent Region) and caught a single individual on rivers. Sites were located in State Forests of the Murrumbidgee River near Hay. He also the Millewa and KoondrooWPerricoota area, recorded their ultrasonic pulses on the Murray about 40 to 50 km SSW of Deniliquin, New River, adjacent to the extensive Millewa/Barmah South Wales (Fig. 1). Most of the extensive 166 Australian Zoologist 31(1) June 1999 forests in this area are dominated by a single detected by the Anabat system for at least species - the River Red Gum Eucalyptus 20 m. camaldulensis. In the past, periodic flooding Anabat detectors were linked to a Delay Switch during winter-spring was an integral feature (Titley Electronics) to allow remote monitoring of the River Red Gum forests along the of sites (Law et al. 1998). Because of high Murray, however, regulation of river flows bat activity levels Delay Switches were only has considerably altered this pattern (Bacon able to extend the 45 min. cassette length to et al. 1993a; Donovan 1997). Flat floodplains an average of 1.9 h of sampling (maximum = dominate the area with occasional sandy 7.5 h). Thus we typically sampled between ridges where White Cypress Pine Callitris 2030 and 2230 h (Eastern Summer Time), glaucophylla replaces E . camaldulensis. Surface covering the period when Jansen (1987) water is plentiful throughout and occurs either caught M. macropus on the Murray River in in the form of large flowing rivers (e.g., South Australia (2 100-2 130 h) and their Murray River, Edward River, Gulpa Creek), emergence times in other parts of New irregularly flowing smaller creeks (e.g., South Wales (B. Law and J. Anderson, pers. Toupna Creek, Warwick Creek), permanent Downloaded from http://meridian.allenpress.com/australian-zoologist/article-pdf/31/1/166/1474892/az_1999_016.pdf by guest on 30 September 2021 obs.). We used the first hour after dark billabongs or ephemeral wetlands. Large water (2030-2130 h), the period of greatest activity bodies, such as Moira Lake, are also present. for most hat species (Law et al. 1998), as our The Millewa group of forests has been base-line for comparisons of activity levels. used for forestry activities for over a century. This was calculated as the mean of the two When the use of riverboats began in the nights sampling at each site. 1850s, areas adjacent to the Murray River were mostly clear-felled for timber (Donovan A bat pass was defined as a sequence of 1997). Regulation of the timber industry and three or more pulses (see Law et al. 1998 silvicultural treatment began in the 1890s, for more details). Bat passes were identified and both have undergone many revisions using zero-crossing analysis and Anabat since that time (Donovan 1997). Despite the Software (Version 5), by comparing call traits long history of logging, large individuals with reference calls recorded from captured of E. camaldulensis with abundant hollows bats released during the survey. For some remain relatively common. The understorey is species captured in low numbers or not at all, characterized by the absence of a shrub layer the authors' reference calls from the south- and a dominance of grasses and sedges (Bacon west slopes, Narrandera and other parts of et al. 1993b). New South Wales were used when making identifications. Some species had calls that Bat survey were difficult to distinguish using Anabat Bats were surveyed at 18 sites in State software. No attempt was made to distinguish Forests during the dark phase of the moon Nyctophilus gouldi from N. geoffroyi on the from 4 to 9 March, 1997. Each site was located basis of calls as they are usually considered at a water-body within River Red Gum forest. indistinguishable. Some overlap occurred Large rivers (4 sites), flowing creeks (2), small in the calls of Vespadelus uulturnus and intermittently-flowing creeks (3), permanent Chalinolobus morio plus Mormoptems species billabongs (4), ephemeral wetlands (3) and and Chalinolobus gouldii. Only calls of high lakes (2) were surveyed. At each site one harp- quality could distinguish these species. trap and one Anabat I1 (Titley Electronics) We did not confidently distinguish the calls ultrasonic detector were deployed for two of at least three species of Monnopterus that consecutive nights. Traps were set directly over could be expected from this area as only water for smaller water bodies and adjacent one species was captured (M. planiceps long to water for larger ones. All detectors were penis = species 1 in Adams et al. 1988). pointed over water at an angle where hats However, comparisons of reference calls of flying near to the water's surface would be M. planiceps short penis (species 3 in Adams recorded. Six sites were trapped and detected et al. 1988), recorded by us at Narrandera, each night. Two additional harp-traps were allowed us to confirm that both species were used to supplement trapping effort at one or present in the Deniliquin forests. In general, two sites each night, giving 46 trap-nights calls of poor quality or short duration were as the total trapping effort for the survey. grouped as unidentified bat passes and Two of the 18 sites could not be trapped incorporated into measures of total bat because they were frequented by the public. activity. The presence of feeding attempts On one night each, we used three additional (feeding buzz) was assessed by listening to survey techniques - mist-netting, trip-lining replays of calls and inspecting call charac- and hand-held ultrasonic detection.