African forest elephant movements depend on time scale and individual behavior

Abstract

The critically endangered African forest elephant (Loxodonta cyclotis) plays a vital role in maintaining the structure and composition of Afrotropical forests, but basic information is lacking regarding the drivers of elephant movement and behavior at landscape scales. We use GPS location data from 96 individuals throughout Gabon to determine how five movement behaviors vary at different scales, how they are influenced by anthropogenic and environmental covariates, and to assess evidence for behavioral syndromes—elephants which share suites of similar movement traits. Elephants show some evidence of behavioral syndromes along an ‘idler’ to ‘explorer’ axis—individuals that move more have larger home ranges and engage in more ‘exploratory’ movements. However, within these groups, forest elephants express remarkable inter-individual variation in movement behaviours. This variation highlights that no two elephants are the same and creates challenges for practitioners aiming to design conservation initiatives.

Long Distance Seed Dispersal by Forest Elephants

“…This empirical distribution was constructed from timestamped GPS movement tracking data of forest elephants in Gabon. These data consist of hourly latitude and longitude coordinates for 96 different elephants collected between 2015 and 2019 (Beirne et al, 2021). Specifically, these hourly observations for each elephant observations were differenced with all subsequent observations to calculate t, change in time, d, change in distance, x, change in east/west distance, and y, change in north/south distance.…”

“…Sex was recorded during the collaring of each elephant. Behavioral syndrome was incorporated as the degree of exploratory behavior from Beirne et al (2021), where negative values represent idlers (small home ranges, short movement distances, and low exploratory behavior) and positive values represent explorers (large home range, long movement distances, and low exploratory behavior).…”

“…Forest elephants consume seeds of more species than any other large vertebrate (Beirne et al, 2020) and are the sole disperser of many large or robustly encapsulated seed species (Guimarães et al, 2008;Beaune et al, 2013). With daily travel distances of 7.4 km per day (Mills et al, 2018) and annual home ranges of 195 km 2 (Beirne et al, 2021), they contribute to LDD. Using coarse GPT categories for small and large seeds, Blake et al (2009) estimated that 88% of elephant-dispersed seeds were moved >1 km and 14% of seeds were moved >10 km from parent plants.…”

“…Forest elephants, however, likely vary in the quality of their seed dispersal services with habitat use, sex and individual behavior. Male elephants, for example, move farther and have larger home range size and weaker site fidelity than females (Beirne et al, 2021). And, forest elephants exhibit distinct behavioral syndromes along an axis that varies from individuals with smaller home ranges, shorter movement distances and less exploratory behavior to those with larger ranges, longer movement distances and more exploratory behavior (Beirne et al, 2021).…”

“…Male elephants, for example, move farther and have larger home range size and weaker site fidelity than females (Beirne et al, 2021). And, forest elephants exhibit distinct behavioral syndromes along an axis that varies from individuals with smaller home ranges, shorter movement distances and less exploratory behavior to those with larger ranges, longer movement distances and more exploratory behavior (Beirne et al, 2021). Finally, poaching and habitat loss have drastically reduced forest elephant populations in the last two decades (Maisels et al, 2013;Poulsen et al, 2017Poulsen et al, , 2018, thus we need to understand how the reduction or loss of seed dispersal services provided by elephants could affect forest species composition.…”