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Understanding maternity roost requirements is fundamental to guide timber production forest management given such roosts are vital to sustain bat populations. We tracked lactating females of three tree cavity-roosting species: Gould's long-eared bat (Nyctophilus gouldi) (n = 7), eastern broad-nosed bat (Scotorepens orion) (n = 6) and little forest bat (Vespadelus vulturnus) (n = 25), over five weeks in young (predominately <5 years old) forest regenerating from heavy timber harvest in southeast Australia. We aimed to investigate interspecific maternity roost selection in a regenerating landscape and by doing so, increase our understanding of the three species' roost ecology. Sixteen V. vulturnus, 15 N. gouldi and six S. orion unique maternity roost trees were located. Bats displayed a degree of maternity roost selection plasticity, however, interspecific differences were found. Nyctophilus gouldi roosted selectively in retained riparian buffers, in trees of high senescence and switched roosts every day. Vespadelus vulturnus roosted in logged areas and displayed high roost site fidelity, with one roost used for 33 consecutive days. Scotorepens orion selected large live trees of low senescence. The preliminary data for this species suggests that females roost most days in 'primary' roosts but display a roost switching behaviour conforming to the fission-fusion model. Dead trees were identified to be important for both N. gouldi and V. vulturnus. Historical and recent logging at our study area drastically reduced cavity-bearing tree density to 1.4 trees per hectare in the logging zones (outside of exclusion areas), potentially limiting local populations of tree cavity-roosting bats and other cavity-dependent wildlife. Our data demonstrate that forest management must consider a range of maternity roost requirements to accommodate differences among species and highlight the importance of exclusion areas for roost habitat. We propose that an expanded 'retention forestry' approach should be implemented in logged areas that includes in-perpetuity forest patch retention to increase habitat complexity and continuity.

Historical patterns of wildfires are being altered as a result of changing climate and therefore are becoming an increasingly pressing global issue. How small mammals deal physiologically with changes in landscape and food availability due to fire remains largely unknown, although recent studies on small heterothermic terrestrial mammals have shown an increase in post-fire torpor use to reduce energy and foraging requirements. However, data on the behavioural and physiological responses of bats after fires are scarce, although potentially these volant species may differ from terrestrial mammals. Therefore, we investigated the post-fire thermal biology and activity of lesser long-eared bats (Nyctophilus geoffroyi) using temperature-telemetry in Warrumbungle National Park, NSW, which experienced a devastating wildfire in 2013. The study comprised two field seasons, one in 2013 within 4 months after the fire, and one in 2015 two years after the fire to identify potential changes in behaviour and physiology. Interestingly, soon after the fire, bats showed significantly shorter torpor bout duration (11.8 ± 12.5 h) and longer normothermia duration (8.7 ± 4.6 h) in comparison to those in 2015 (torpor bout duration: 24.1 ± 23.5 h; normothermia duration: 2.5 ± 1.5 h). Insect availability was significantly (20-fold) higher in 2013 than in 2015, which was likely an important factor resulting in the short average torpor bout duration by N. geoffroyi after the fire. Our data indicate that volant bats appear to show the opposite post-fire behavioural and physiological responses to small terrestrial mammals, showing longer normothermic and active periods and shorter torpor bouts to capitalise on an increase in available post-fire resources.

Insectivorous bats have often been touted as biological control for mosquito populations. However, mosquitoes generally represent only a small proportion of bat diet. Given the small size of mosquitoes, restrictions imposed on prey detectability by low frequency echolocation, and variable field metabolic rates (FMR), mosquitoes may not be available to or profitable for all bats. This study investigated whether consumption of mosquitoes was influenced by bat size, which is negatively correlated with echolocation frequency but positively correlated with bat FMR. To assess this, we investigated diets of five eastern Australian bat species (Vespadelus vulturnus Thomas, V. pumilus Gray, Miniopterus australis Tomes, Nyctophilus gouldi Tomes and Chalinolobus gouldii Gray) ranging in size from 4-14 g in coastal forest, using molecular analysis of fecal DNA. Abundances of potential mosquito and non-mosquito prey were concurrently measured to provide data on relative prey abundance. Aedes vigilax was locally the most abundant mosquito species, while Lepidoptera the most abundant insect order. A diverse range of prey was detected in bat feces, although members of Lepidoptera dominated, reflecting relative abundance at trap sites. Consumption of mosquitoes was restricted to V. vulturnus and V. pumilus, two smaller sized bats (4 and 4.5 g). Although mosquitoes were not commonly detected in feces of V. pumilus, they were present in feces of 55 % of V. vulturnus individuals. To meet nightly FMR requirements, Vespadelus spp. would need to consume ~600-660 mosquitoes on a mosquito-only diet, or ~160-180 similar sized moths on a moth-only diet. Lower relative profitability of mosquitoes may provide an explanation for the low level of mosquito consumption among these bats and the absence of mosquitoes in feces of larger bats. Smaller sized bats, especially V. vulturnus, are likely to be those most sensitive to reductions in mosquito abundance and should be monitored during mosquito control activities.

The need to develop effective management strategies for insectivorous bat populations requires an understanding of factors influencing habitat use. Availability of pest prey, such as mosquitoes is likely to be one such factor. To assess whether this is the case, we radio-tracked Vespadelus vulturnus Thomas (little forest bat), a predator of Aedes vigilax Skuse (saltmarsh mosquito), in saltmarsh and adjacent coastal swamp forest during periods of high and low Ae. vigilax abundance. When mosquito abundance in structurally-open saltmarsh was similar to the more cluttered coastal swamp forest, use of saltmarsh by V. vulturnus was disproportionately greater than its availability, with saltmarsh selected preferentially for foraging. However, at times of low Ae. vigilax abundance in saltmarsh, use of saltmarsh by V. vulturnus was reduced and all habitats were used in proportion to availability in the study area. This is the first radio-tracking study to demonstrate a shift in foraging range by an insectivorous bat species correlated with fluctuations in the distribution and abundance of a particular prey resource. The shift in foraging range by V. vulturnus, corresponding with a spatio-temporal variation in abundance of Ae. vigilax highlights the importance of mosquitoes as a dietary item. Broadscale pest control of Ae. vigilax may have ecological implications for the diet and habitat use of V. vulturnus. An adaptive management approach is proposed, whereby careful monitoring of insectivorous bat populations is recommended before and after any application of broadscale mosquito control measures. We also suggest a precautionary approach is taken such that broadscale control of mosquitoes avoids the lactation period of bats, a time when their energetic demands are greatest and when there is reduced risk of contracting mosquito-borne diseases transmitted by Ae. vigilax.

Schemes designed to make farming landscapes less hostile to wildlife have been questioned because target taxa do not always respond in the expected manner. Microbats are often overlooked in this process, yet persist in agricultural landscapes and exert top-down control of crop pests. We investigated the relationship between microbats and measures commonly incorporated into agri-environment schemes, to derive management recommendations for their ongoing conservation. We used acoustic detectors to quantify bat species richness, activity, and feeding in 32 linear remnants and adjacent fields across an agricultural region of New South Wales, Australia. Nocturnal arthropods were simultaneously trapped using black-light traps. We recorded 91,969 bat calls, 17,277 of which could be attributed to one of the 13 taxa recorded, and 491 calls contained feeding buzzes. The linear remnants supported higher bat activity than the fields, but species richness and feeding activity did not significantly differ. We trapped a mean 87.6 g (±17.6 g SE) of arthropods per night, but found no differences in biomass between land uses. Wider linear remnants with intact native vegetation supported more bat species, as did those adjacent to unsealed, as opposed to sealed roads. Fields of unimproved native pastures, with more retained scattered trees and associated hollows and logs, supported the greatest bat species richness and activity. We conclude that the juxtaposition of linear remnants of intact vegetation and scattered trees in fields, coupled with less-intensive land uses such as unimproved pastures will benefit bat communities in agricultural landscapes, and should be incorporated into agri-environment schemes. In contrast, sealed roads may act as a deterrent. The "wildlife friendly farming" vs "land sparing" debate has so far primarily focussed on birds, but here we have found evidence that the integration of both approaches could particularly benefit bats.

Over half of the world's forests are secondary regrowth and support considerable biodiversity. Thinning of these forests is a widespread management practice that can affect forest species, including echolocating bats and their prey., We compared total activity of 11 bat taxa, foraging activity of six bat guilds and biomass of 11 insect orders across four forest thinning categories in managed remnant eucalypt forests in south-eastern Australia: unthinned regrowth, forest thinned recently (0-4 years) and in the medium term (5-10 years) and reference (mature open forest). Thinning had been carried out at large (˜350 ha) spatial scales., Total bat activity was 60% less and foraging activity was 80% less in unthinned regrowth, compared to reference sites, but activity levels were similar among thinned and reference sites. Insect biomass was greatest in unthinned sites, and while bat activity was related to prey biomass, this relationship was weak in unthinned sites. Together, this suggests that forest structure was more important than prey availability or time since thinning in influencing bat activity patterns., Synthesizing our findings with the broader literature on bats and thinning, we found support for a clutter threshold of 1100 stems ha−1, above which bat activity was markedly lower, across two continents (the USA and Australia) and four broad vegetation types (eucalypt, conifer, deciduous and mixed forests)., While elsewhere bats with adaptive traits for open habitats generally respond positively to thinning, in our study, species with traits consistent with clutter tolerance (high call frequency and low wing aspect ratio) had lowest activity levels (up to 22 times) in unthinned regrowth compared to all other forest types., Synthesis and applications. Widespread dense regrowth forest can restrict movement and foraging of bats, even those adapted to clutter. We recommend thinning dense regrowth or plantations to below 1100 stems ha−1 when targeting bat foraging habitat, but effects of thinning on roost habitat and other forest biota require further investigation. [ABSTRACT FROM AUTHOR]

Floodplain ecosystems across the world have declined with river regulation and floodplain development, reducing flood frequency and extent and fragmenting flood-dependent vegetation. There is growing evidence that these changes to flooding disproportionately affect terrestrial taxa, such as bats. We compared bat activity and insect abundance across the floodplain mosaic (river, lake, vegetated wetland, floodplain forest, floodplain woodland) representing decreasing flooding histories, and two dry habitats (dry vegetation, agricultural). We replicated these habitats in each of six floodplain systems of the Murray-Darling Basin, a large semi-arid river basin (1,042,730 km 2 ) in south-eastern Australia. Our sites were spread across > 400,000 km 2 , traversing climatic and hydrological gradients. Rivers and lakes with open water and riparian trees had greater total activity (5 times), foraging activity (14 times) and bat richness (1.5 times) than dry vegetation. Activities of all mesic bat species, as well as some widespread and arid-adapted bat species, were positively associated with floodplain habitats when compared with dry vegetation. Lowest overall total activity, foraging activity and richness were observed in dry agricultural (cropping, grazing and fallow) habitats, with two of six threatened species in our study area never recorded in agricultural habitats. Prey abundance was not correlated with bat activity or habitat. The mosaic of floodplain habitats appears to be of disproportionate value for bat communities compared to dominant land covers of agricultural and dry vegetation. Loss of floodplain habitats through continued river regulation and floodplain development are likely reduce diversity and abundance of bats that rely on floodplains for foraging and roosting. Lags in bat roost formation and forest structure mean these changes could take over a century to reverse. To sustain bat communities, we recommend increasing environmental flows to floodplains during the bat lactating season, implementing stronger protection of floodplains from river regulation and floodplain development and where possible, restoring floodplains affected by agriculture into functioning wetlands. [ABSTRACT FROM AUTHOR]

Three-dimensional structure of vegetation plays a key role in animal ecology and the arrival of LiDAR technologies has given ecologists the ability to understand species-habitat relationships in increasing detail. However, few studies have investigated the trait-environment relationships that underpin diverse animal relationships with vegetation structure. We used terrestrial laser scanning (TLS) and acoustic bat surveys to investigate relationships between forest structure and bat communities across a vegetation structural gradient at community, species and trait levels. We developed 20 measures of site scale vegetation structure and also quantified landscape scale vegetation cover and water availability. We predicted that overall bat activity would increase in open and decrease in cluttered vegetation, but this would vary with species, underpinned by ecomorphological traits. Overall bat activity was negatively associated with stem density, with total activity halving (from 380 to 190 calls night − 1 ) as stem densities increased from 60 to 1350 stems ha − 1 , while foraging activity declined from 8 to < 1 feeding buzzes night − 1 over the same range. Bat activity varied among species and structures and foraging strategy explained more of this variability than call, body size or wing traits. As predicted, above-canopy and edge-space foraging bats were negatively associated with local-scale clutter, while closed-space species were positively associated with cluttered stands. Stem density was the strongest predictor of bat-environment relationships, although there was evidence for differences in bat habitat use across different structural elements. Our study is the first to link detailed LiDAR-derived 3D forest structural metrics to multiple animal traits. [ABSTRACT FROM AUTHOR]

Coastal lagoons provide key habitat for a wide range of biota but are often degraded by intense urbanization pressures. Insectivorous bats use these highly productive ecosystems and are likely to be impacted by their decline in quality. We compared bat activity and richness and invertebrate biomass and richness across a gradient of lagoon quality (9 lagoons) in the Greater Sydney region, Australia to determine the extent to which bats and their prey were impacted by lagoon degradation. Bats were more diverse and 19 times more active at higher quality lagoons. The trawling bat, Myotis macropus , was absent from all low quality lagoons, but these lagoons were used by other species such as Miniopterus schreibersii oceanensis . Invertebrate richness and biomass did not differ significantly across lagoon quality. We examined potential mechanisms of insectivorous bat decline at degraded lagoons by measuring toxic metal concentrations in bat fur, invertebrates and sediment. Lead and zinc were detected at environmentally significant levels in the sediments of lower quality lagoons. Furthermore, lead concentrations were 6 times the lowest observable adverse effects level for small mammals in the hair of one individual M. macropus . The present study demonstrates that coastal lagoons support a rich bat community, but ongoing development and pollution of these habitats is likely to negatively impact on insectivorous bat species, especially trawling species. [ABSTRACT FROM AUTHOR]