Understory bat roosts, availability and occupation patterns in a Neotropical rainforest of Costa Rica

Abstract

Abstract:The strong link between bats and their roosts is widely recognized as being particularly significant. Despite this, roosting ecology of bats is poorly understood and much of the basic information is still unknown. In this study, we investigated the availability and occupation patterns of four roost types (trees, caves, termite nests and tents) used by bats at Tirimbina Biological Reserve (TBR), Costa Rica. To accomplish our aim, we systematically surveyed both sides of established trails and transects, looking for understory roosts. Potential roosts were examined for bat presence in order to establish occupation. Roost availability and density were estimated using traveled distances (km) and inspected area (10 m for trees/caves and 15 m for tents/termite nests) of each trail or transect sampled. For the tent roosts, data on taxonomic information of plant modified, type of architecture, condition and construction achievement were also recorded. The area surveyed represented 45.4 % of the total area of the TBR (345 ha). Tents were the most common roost (56.6 % of all roosts, N = 223), followed by trees (24.4 %, N = 96), termite nests (18.8 %, N = 74) and caves (0.2 %, N = 1). We detected only 27 roosts occupied by bats (6.8 % of all roosts, 0.17 occupied roosts/ha). Caves showed the highest occupation rate (100 %, N = 1), followed by trees (17.7 %, N = 17), tents (3.6 %, N = 8) and termite nests (1.3 %, N = 1). We found the roosts for 10 species, representing 33.9 % of the bat fauna documented at the reserve (62 species). Density of roosts per bat species varied between 0.017-0.138 roosts/ha. Phyllostomidae was the best-represented family with Micronycteris microtis representing the most common species encountered. Four distinct tent architectures were documented. Bifid architecture was the most common (133 tents), followed by Conical (47 tents), Apical (27 tents) and Inverted Boat (16 tents). Most of the tents found were healthy (76.7 %, N = 171) and totally constructed (88.8 %, N = 198). Our study demonstrated that occupied bat roosts are difficult to find in the forest. When compared to the roost availability, the low occupation rates suggested that, at least in our study area, roosts might not be a limiting resource. Nevertheless, to confirm this hypothesis, information about fidelity and selection process of the species is fundamental for understanding to what extent these roosts meet the requirements to be inhabited or modified. Worldwide conservation efforts on bats should focus on understanding roosting ecology, especially due to anthropogenic pressures that are continuously reducing the availability of roosts, which undoubtedly contributes to the risk of extinction for specialized and sensitive species. Rev. Biol. Trop. 64 (3): 1333-1343. Epub 2016 September 01.Key words: Costa Rica, Neotropical bats, Phyllostomidae, roosting ecology, bat tents, Sarapiquí.Neotropical bat species are particularly abundant and diverse (Fenton, 1992;Kalko, 1998 (Kalko, 1998) and roost availability (Humphrey, 1975;Ka...

Out of thin air: surveying tropical bat roosts through air sampling of eDNA

“…The copyright holder for this preprint this version posted November 8, 2022. ; https://doi.org/10.1101/2022.11.07.515479 doi: bioRxiv preprint tunnels and we have observed them roosting in the sugar mill structures near the tree roost where they were detected. They have been observed emerging from tree roosts in our study area and are known to roost in hollow trees elsewhere in the neotropics (Villalobos-Chaves et al, 2016;Voss et al, 2016), thus their detection in both the artificial tunnels where they were seen, and in the hollow tree roosts, is consistent with documented roosting behaviour. While it is believed that S. parvidens do sometimes roost in caves (or cave-like structures) as our data suggested and often co-roosts with other bats, they had not previously been observed doing this in the local area.…”

“…Bat species are characterized by a wide variety of roosting ecologies (Fenton & Ratcliffe, 2010; Voss et al, 2016) utilizing caves, trees, man-made structures, cracks in rocks (Altringham, 2011), leaf litter (Mormann & Robbins, 2007), and even pitcher plants (Grafe et al, 2011). Some species modify the environment to create their roosts (e.g., creating leaf tents (Kunz, 1982) or excavating roosts within termite mounds (Esquivel et al, 2020)) and multiple species may use the same roost (Villalobos-Chaves et al, 2016; Kelm, Toelch & Jones, 2021). Bats require safe roosts that provide protection from predators with appropriate environmental conditions related to temperature and humidity.…”

Roosting ecology of Stenodermatinae bats (Phyllostomidae): evolution of foliage roosting and correlated phenotypes

“…(); 117 Vieira (); 118 Villalobos‐Chaves et al. (); 119 Voss et al. (); 120 Webster and Jones (); 121 Zortéa (); 122 Zortéa and De Brito (); 123 this study.…”

The Influences of Micro- and Macro-Habitat Variables on Tent-Roosting in Dermanura watsoni on the Osa Peninsula, Costa Rica

“…Habitat type had no significant effect on the number of tents or the number of plants with tents. Many non-independent variables may influence tent construction type and plant species used to construct tents even in the same area and habitat type (Choe and Timm, 1985;Chaverri and Kunz, 2006b;Rodríguez-Herrera, Medellín and Timm, 2007;Villalobos-Chaves et al, 2016;this study).…”