Roosting ecology of insectivorous bats in a tropical agricultural landscape

Bats spend more than half of their life in roosts, where key life events transpire. Therefore the availability and selection of roosts are important to bats everywhere, and may limit their ability to exploit every habitat, including agricultural landscapes such as paddy fields, orchards and tea plantations. This study aimed to investigate the day roosts used by insectivorous bat species in tea plantations of Sri Lanka. We surveyed 18 tea plantations where we recorded a total of 44 roosts involving five families and nine species of bats (Hipposideros galeritus, Hipposideros lankadiva, Hipposideros speoris, Rhinolophus beddomei, Rhinolophus rouxii, Megaderma spasma, Pipistrellus ceylonicus, Pipistrellus coromandra and Miniopterus cf. fuliginosus). Most (26) of the recorded roosts were geomorphic, (11) were anthropogenic, and (7) were in vegetation. H. lankadiva and M. cf. fuliginosus are the only species known to roost exclusively in geomorphic roosts; all others were opportunistic. Although protecting bat roosts is crucial for their conservation, it is challenging in view of existing tea management practices. Therefore, natural roosts should be maintained and protected. The introduction of artificial roosts might increase the number of bats able to forage over tea plantations and maximize their consumption of agricultural pests, thereby increasing tea production.

Conventional wisdom on roosting behaviour of Australian flying foxes - a critical review, and evaluation using new data

1. Fruit bats (Family: Pteropodidae) are animals of great ecological and economic importance, yet their populations are threatened by ongoing habitat loss and human persecution. A lack of ecological knowledge for the vast majority of Pteropodid bat species presents additional challenges for their conservation and management. 2. In Australia, populations of flying-fox species (Genus: Pteropus) are declining and management approaches are highly contentious. Australian flying-fox roosts are exposed to management regimes involving habitat modification, either through human-wildlife conflict management policies, or vegetation restoration programs. Details on the fine-scale roosting ecology of flying-foxes are not sufficiently known to provide evidence-based guidance for these regimes and the impact on flying-foxes of these habitat modifications is poorly understood. 3. We seek to identify and test commonly held understandings about the roosting ecology of Australian flying-foxes to inform practical recommendations and guide and refine management practices at flying-fox roosts. 4. We identify 31 statements relevant to understanding of flying-fox roosting structure, and synthesise these in the context of existing literature. We then contribute contemporary data on the fine-scale roosting structure of flying-fox species in south-eastern Queensland and north-eastern New South Wales, presenting a 13-month dataset from 2,522 spatially referenced roost trees across eight sites. 5. We show evidence of sympatry and indirect competition between species, including spatial segregation of black and grey-headed flying-foxes within roosts and seasonal displacement of both species by little red flying-foxes. We demonstrate roost-specific annual trends in occupancy and abundance and provide updated demographic information including the spatial and temporal distributions of males and females within roosts. 6. Insights from our systematic and quantitative study will be important to guide evidence-based recommendations on restoration and management and will be crucial for the implementation of priority recovery actions for the preservation of these species into the future.

Conventional wisdom on roosting behaviour of Australian flying foxes -- a critical review, and evaluation using new data

1. Fruit bats (Family: Pteropodidae) are animals of great ecological and economic importance, yet their populations are threatened by ongoing habitat loss and human persecution. A lack of ecological knowledge for the vast majority of Pteropodid bat species presents additional challenges for their conservation and management. 2. In Australia, populations of flying-fox species (Genus: Pteropus) are declining and management approaches are highly contentious. Australian flying-fox roosts are exposed to management regimes involving habitat modification, either through human-wildlife conflict management policies, or vegetation restoration programs. Details on the fine-scale roosting ecology of flying-foxes are not sufficiently known to provide evidence-based guidance for these regimes and the impact on flying-foxes of these habitat modifications is poorly understood. 3. We seek to identify and test commonly held understandings about the roosting ecology of Australian flying-foxes to inform practical recommendations and guide and refine management practices at flying-fox roosts. 4. We identify 31 statements relevant to understanding of flying-fox roosting structure, and synthesise these in the context of existing literature. We then contribute contemporary data on the fine-scale roosting structure of flying-fox species in south-eastern Queensland and north-eastern New South Wales, presenting a 13-month dataset from 2,522 spatially referenced roost trees across eight sites. 5. We show evidence of sympatry and indirect competition between species, including spatial segregation of black and grey-headed flying-foxes within roosts and seasonal displacement of both species by little red flying-foxes. We demonstrate roost-specific annual trends in occupancy and abundance and provide updated demographic information including the spatial and temporal distributions of males and females within roosts. 6. Insights from our systematic and quantitative study will be important to guide evidence-based recommendations on restoration and management and will be crucial for the implementation of priority recovery actions for the preservation of these species into the future.

Summer roosts of “The revenant” flat-headed myotis, Myotis planiceps

The flat-headed myotis (Myotis planiceps) was declared extinct in 1996 but rediscovered in 2004, thus the reference to a revenant, one who came back from the dead, as it was declared extinct in 1996 but rediscovered in 2004. However, the species still faces serious extinction risk. To aid in the strategic planning and priorities for conservation, we studied roosting ecology. These bats inhabit the Chihuahuan Desert in one of the smallest distributional ranges of any mammal. Using radiotelemetry, we located 25 summer roosts, all in the skirts of dry leaves of yucca trees (Yucca carnerosana). We conclude that to roost, these bats search for clumps of tall yucca trees with a mean height of 3.93 m and mean width of skirts of 1.35 m.

Roosting ecology and morphometric analysis of Pteropus medius (Indian flying fox) in Lower Dir, district, Pakistan

The present study was conducted to explore morphometric variations of Pteropus medius (the Indian flying fox) and the roosting trees in Lower Dir, Pakistan. The bats were captured from Morus alba, Morus nigra, Brousonetia papyrifera, Pinus raxburghii, Hevea brasiliensis, Platanus orientalis, Populous nigra, Melia azedarach, Eucalyptus camaldulensis and Grevillea robusta through sling shot and mess net methods. A total of 12 bats were studied for the differential morphological features based on age and sex. Male bats were recorded higher in weight than females. The variations were found in body mass (821.1±34.65gm), circumference of body with wings (25.43±0.39cm), wingspan (112.58±1.90cm), Body length (20.73±0.68cm), Snout length (3.42±0.04cm), Eye length (1.45±0.033cm), Length of ear (3.56±0.05cm), Width of ear (2.46±0.04cm), Length b/w ear (5.51±0.11cm), Circumference of neck (12.23±0.24cm), Circumference of body without wings (18.68±0.31cm), Arm wing length (23.2±1.03cm), Length of thumb (5.43±0.1cm), Length of nail (1.89±0.05cm), Hand wing length (29.1±0.51cm), Maximum width of wing (21.03±0.68cm), Length b/w tip of wing to 5th digit (29.39±0.30cm), Length b/w 5th digit to foot (22.97±1.09cm), Length b/w feet (18.31±0.74cm) and Length of foot claw (4.23±0.05cm). This study was designed for analysis of external morphological variations for P. medius (the Indian flying fox) that may help in identification of these bats and their roosting sites.

Roosting ecology of the southernmost bats, Myotis chiloensis and Histiotus magellanicus, in southern Tierra del Fuego, Chile

ABSTRACTThere are few studies of day-roosting ecology of bats inhabiting the southernmost forests of South America, where cool summer temperatures and land management practices pose several challenges. The goal of the present study was to describe day-roosting habitats and patterns of thermoregulation in two bat species occurring on Tierra del Fuego, Myotis chiloensis (Chilean myotis) and Histiotus magellanicus (southern big-eared brown bat), during late spring. To do so, we tagged 17 bats with temperature-sensitive radio-transmitters, located 17 day-roosts, and collected 81 days of skin temperature data. We concurrently recorded ambient air temperature to determine its effect on torpor use. Both species were found roosting in large diameter (77.8 ± 6 cm), typically live, Nothofagus pumilio trees (lenga) located on the edges of forest gaps or within stands primarily composed of smaller, younger trees. Bats of both species frequently used torpor, with skin temperatures dropping below a torpor threshold on 89% of days (n = 72) and daily minimum skin temperatures averaging 16.5 °C over the course of our study. Average daily air temperature was a significant predictor of torpor use, with lower skin temperatures and more time spent in torpor observed on colder days. Minimum skin temperature and time spent torpid did not vary between bat species, nor did the characteristics of day-roosts. These data show that spring temperatures in Tierra del Fuego pose an energetic challenge that bats meet through frequent use of torpor, and likely, habitat selection. We recommend local conservation efforts keep these thermal challenges in mind by retaining large trees, which may provide warmer microclimates or room for social groups.