African forest elephant movements depend on time scale and individual behavior

Christopher Beirne,Connie J Clark,Lee J T White,Joseph Okouyi,Thomas M Houslay,John R Poulsen,Mike Fay,Peter Morkel

doi:10.1038/s41598-021-91627-z

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.

Highlights

That compose a small fraction of their extant range
We derive five individual-level movement behaviors from forest elephant GPS tracking data: movement distance, home range size, site fidelity, diurnality and exploratory behavior—each of which captures an important aspect of movement ecology
Home range is an important parameter for designing wildlife management strategies—how much area does a forest elephant require in a given period of time? ‘Site fidelity’ reflects the degree to which individuals remain in one location or move freely around the landscape and has been shown to govern survival and reproductive success in multiple t axa[22,23]

Summary

Introduction

That compose a small fraction of their extant range. Given the rapid rate of decline of forest elephant populations across their range (60–80% within ten years:16,17), landscape-scale characterization of the drivers of movement, and its associated individual variation, is vital for the design of effective conservation and management strategies[18], forecasting how forest elephants will cope with future environmental c hange[18,19], and determining how their absence will transform tropical forest ecosystems[15]. We derive five individual-level movement behaviors from forest elephant GPS tracking data: movement distance, home range size, site fidelity, diurnality and exploratory behavior—each of which captures an important aspect of movement ecology. The relative amount of time individuals spend in exploratory movements versus resting/foraging (shorter movements with low directional persistence) is important for understanding individual foraging decisions, social interactions and responses to anthropogenic disturbances[29,30] Characterizing these movement behaviors and the factors that influence them is important for effective conservation; for example, to ensure that reserves or corridors are large enough, properly configured, and allow for seasonal and/ or anthropogenically-induced behavioral changes. We employ data from the largest forest elephant GPS collaring program to date to explore how the movement behaviors of 96 individuals in Gabon are influenced by both intrinsic (sex) and extrinsic factors (rainfall, temperature seasonality and anthropogenic disturbance).

Methods

Results

Conclusion