Limited use of bat boxes in a rural landscape: implications for offsetting the clearing of hollow‐bearing trees

Abstract

Bat boxes frequently form part of hollow-bearing tree offsets; however, their effectiveness is poorly documented. We investigated the effectiveness of a bat box program designed to partially offset tree hollow loss from clearing for a coal mine. During the first year of monitoring, we detected bats in 5% of 1,308 box checks. Only 3 of 13 local tree cavity-roosting bat species/species groups used boxes and occupancy was not strongly associated with modeled box and site attributes. In the second year, we tested two hypotheses that may explain the relatively low box use: (1) solar exposure of boxes was inadequate for heterothermic bats and (2) available box designs were of low suitability. Relocating boxes to increase solar exposure did not increase use, or enhance the temperature profiles of relocated boxes. Introduction of a new box design led to 11 times higher use compared with existing designs for Nyctophilus spp. (long-eared bat). Overall, our data suggest that the bat box program was ineffective due to few bat species using boxes, infrequent box use by three species, and rarity of maternity roosting. The knowledge gap of species-specific box designs and roosting ecology limits the effectiveness of boxes to offset cleared hollow-bearing trees. Lack of knowledge and the widespread use of bat boxes to offset lost tree hollows highlights the need to (1) rigorously protect hollow-bearing trees and (2) advance our understanding of species-specific roost ecology, box design preferences and mechanical hollow creation into trees, before artificial hollows can be considered a meaningful offset measure.

Avoiding a conservation pitfall: Considering the risks of unsuitably hot bat boxes

“…The direct fitness effects of parasite accumulation, predation, and behavioral alteration are largely unexplored for bat populations using bat boxes. In many scenarios, bat boxes may not be the best or optimal solution for providing bats with beneficial alternate roosting habitat (Griffiths, Bender, Godinho, Lentini, & Lumsden, 2017; López‐Baucells et al, 2017; Rueegger et al, 2019). We suggest researchers investigate alternatives to bat box deployment.…”

“…Human‐induced land use changes may eliminate natural roosting and nesting habitats for wildlife, particularly for species that typically roost in cavities and crevices in mature trees. Practitioners often supply “nest” boxes as alternative roosts (e.g., Arias, Gignoux‐Wofsohn, Kerwin, & Maslo, 2020; Collins, Ross, Ferguson, Williams, & Langton, 2020; Lindenmayer et al, 2017; Rueegger, Goldingay, Law, & Gonsalves, 2019); such roosts are commonly deployed for bats (Flaquer, Torre, & Ruiz‐Jarillo, 2006; Mering & Chambers, 2012; Mering & Chambers, 2014), birds (De León & Mínguez, 2003; Demeyrier, Lambrechts, Perret, & Grégoire, 2016; Stephens, Kaminski, Leopold, & Gerard, 1998), rodents (Iwińska, Boratyński, Trivedi, & Borowski, 2020), and marsupials (Beyer & Goldingay, 2006; Isaac, Parsons, & Goodman, 2008; Rueegger, Goldingay, & Brookes, 2012). While intended to enhance the recovery and persistence of at‐risk species, on some occasions these artificial structures have adverse negative effects, leading to low survival and fecundity (e.g., Klein, Nagy, Csörgo, & Mátics, 2007; Miller, 2002; Semel, Sherman, & Byers, 1988).…”

Nest box contentions: Are nest boxes used by the species they target?

“…That project was deemed a failure due to a paucity of nest box use by the target species. An evaluation of a bat box project at a mine site by Rueegger et al (2019) also highlighted a lack of research knowledge that has hindered evaluation and prospects of a successful outcome.…”

No evidence for memory retention of a learned association between a cue and roost quality after hibernation in free‐ranging bats

“…From an applied conservation perspective, getting insights into species’ behavioral responses in their habitat is essential for planning adequate conservation measures (Berger‐Tal et al., 2011). In the particular case of bats, how species react to new roosting options (i.e., exploration and use) determines, in the long term, the success of species management measures (Rueegger, Goldingay, Law, & Gonsalves, 2019; Zeale et al., 2016).…”