Interplay between local and landscape-scale effects on the taxonomic, functional and phylogenetic diversity of aerial insectivorous neotropical bats

Abstract

Context Human-modified landscapes are globally ubiquitous. It is critical to understand how habitat loss and fragmentation impact biodiversity from both a local habitat context and landscape-scale perspective to inform land management and conservation strategies. Objectives We used an experimentally fragmented landscape in the Brazilian Amazon to investigate variation in aerial insectivorous bat diversity in response to local habitat and wider landscape characteristics, applying a multiscale approach. Methods We conducted bat acoustic surveys at 33 sites, comprising old secondary forests and fragments of primary forest. Taxonomic, functional and phylogenetic diversity facets were calculated within a Hill numbers framework. We analysed responses to fragment size, interior-edge-matrix gradients, as well as local vegetation structure, continuous forest cover, edge density and patch density across five spatial scales (0.5−3 km) surrounding detector locations. Results Compared with continuous forest, secondary forest matrix around the smallest fragments harboured lower diversity. The overall negative effect of the matrix became less pronounced with increasing fragment size. In contrast, forest edges generally contained higher taxonomic, functional and phylogenetic diversity. We found subtle scale-sensitive associations for functional diversity, responding positively to forest cover (at the 1 km scale) and negatively to edge (1 km scale) and patch density (2.5 km scale). Conclusions Despite a low-contrast matrix of tall secondary forest surrounding fragments after ~ 30 years of forest recovery, aerial insectivorous bat diversity is not comparable to continuous primary forest. Assemblage functional diversity responds to compositional and configurational landscape characteristics at scales deserving further evaluation at guild and species level.

Secondary forest buffers the effects of fragmentation on aerial insectivorous bat species following 30 years of passive forest restoration

“…Appel et al (2021b) found elevated activity levels in secondary forest compared to continuous forest, however P. alitonus and P. rubiginosus exhibited foraging plasticity with increased activity in continuous forest on bright moonlit nights, possibly to reduce threats from avian predators. This flexibility was only evident in Pteronotus species which produce high duty cycle constant-frequency echolocation calls, allowing them to accurately detect small mobile prey items in dense vegetation (Estrada-Villegas et al 2012;de Oliveira et al 2015;L opez-Baucells et al 2018). They are well adapted to forage in regenerating forests where understory vegetation may be heavily cluttered.…”

“…For each of the 33 sampling sites, within three plots of 100 m 2 (5 × 20 m) around the detector locations (during the same period as the acoustic sampling) we quantified seven vegetation variables (López‐Baucells et al 2022): (1) number of trees (>10 cm diameter at breast height [DBH]); (2) number of woody stems (<10 cm DBH); (3) average DBH of trees (>10 cm); (4) percentage canopy cover; (5) liana density (visually classified every 5 m in five categories varying from no lianas to very high liana density); (6) canopy height (based on visual estimation); and (7) vertical stratification in vegetation density.) To reduce the dimensionality of the data, we performed a principal components analysis (PCA) (López‐Baucells et al 2022). The first axis explained 38.3% of total variance (Table S2; Fig.…”

“…Farneda et al 2018, 2022; Rocha et al 2018), recent research has also targeted the ensemble of aerial insectivorous bats (e.g. Appel et al 2021 b ; López‐Baucells et al 2022; Yoh et al 2022), which comprises a considerable fraction of the BDFFP bat fauna.…”

“…Multi‐dimensional (taxonomic, functional, and phylogenetic) diversity responses of the aerial insectivorous bat ensemble to vegetation and landscape structure indicated subtle scale‐sensitive associations for functional diversity only (López‐Baucells et al 2022). The regenerating secondary forest matrix around the smallest fragments was found to accommodate significantly lower diversity compared to the continuous forest.…”

“…Here, we build on our previous multi‐dimensional diversity analysis (López‐Baucells et al 2022) and investigated (1) how species‐specific occupancy and activity differ across the four main habitats (continuous forest [CF], forest fragment interiors [I], fragment edges [E], and secondary forest matrix sites [M]), considering both the disturbance interior‐edge‐matrix [IEM]) and fragment‐size gradients; and (2) whether local vegetation structure and landscape metrics influence activity across multiple spatial scales. These comparisons were conducted for a selection of common species/sonotypes and four functional guilds (edge foragers [EF], forest specialists [FS], flexible forest foragers [FF] and open space specialists [OS] sensu Yoh et al 2022).…”