Previous light-weight GPS-logger studies elucidated bat’s navigation and social foraging behavior and revealed how landscape characteristics shape movement patterns.
We hypothesize that the Japanese greater horseshoe bat’s movement behavior is influenced by the landscape context (semi-natural vs. anthropogenic), resulting in differences in movement measures.
GPS-data from 8 females (19 trips), collected from 2015 to 2018 in semi-natural (Hokkaido) and anthropogenic (Fukui prefecture) landscapes of Japan, were analyzed for differences in total flight distance and foraging behavior. For the latter, we excluded data logged with large intervals (semi-natural landscape: n=2) and classified each trip’s GPS-points into “foraging” or “commuting” categories using DBSCAN (Density-Based Spatial Clustering). All data was analyzed using either generalized or linear mixed effect models in R.
Bats in the semi-natural landscape traveled farther (10.8±1.3 km per trip) and used more foraging grounds (6±1.4) that were located within forests compared to bats in the anthropogenic landscape (3.9±1.3 km, 2.5±1.1) that also used residential areas.
We conclude that bats in a semi-natural landscape might be increasing energy intake by frequently leaving a foraging patch for a more profitable one (marginal value theorem), while bats in the anthropogenic landscape might be reducing flight costs by traveling to few, close foraging patches.