Hammer-headed bat movement behavior and habitat selection

Background: Animals with key ecological roles, such as seed-dispersing
fruit bats, rely to varying degrees on habitat structure to indicate the
locations of rewards and risks. Methods: To understand how variation in
vegetation structure influences fruit bat selection, we related movement
steps of hammer-headed bats (Hypsignathus monstrosus) to attributes of
canopy height, vertical and horizontal structure, and habitat type in a
mature rainforest of southern Cameroon. Vegetation structural metrics were
measured with UAV-LiDAR at 10 m resolution for a 25 km2 study area.
Because bats frequently moved outside the study area, we also
characterized vegetation height and horizontal complexity over the full
extent of bat movement trajectories by upscaling UAV-LiDAR measurements
using spaceborne remote sensing, including GEDI LiDAR data. Results: At
the site level, hammer-headed bats preferred areas of intermediate canopy
height close to large canopy gaps (≥500 m). Individual bats varied in
selection for vertical vegetation complexity, distance to smaller canopy
gaps (≥50 m), and plant volume density of intermediate vegetation strata
(10-20 m). Over the full extent of movement trajectories, hammer-headed
bats consistently preferred intermediate canopy height, and areas closer
to canopy gaps. At both spatial extents, bats moved the shortest distances
in swamp habitats dominated by Raphia palms. These behaviors indicate use
of forest types that vary structurally, with a preference for open
airspace during foraging or moving among resources, and for dense swamp
vegetation during roosting and foraging periods. In addition, most bats
regularly made long flights of up to 17.7 km shortly after sunset and
before sunrise and limited their movements to three or fewer destinations
throughout the tracking period. Conclusions: These results highlight the
importance of integrating remote sensing and animal tracking data to
understand habitat selection of a species whose movements influence viral
spillover risk and spatial patterns of seed dispersal.