Animal displacement as a responsive movement trait for biodiversity monitoring

Animal movement provides high-resolution insights into how species respond to human disturbances. However, such temporal dynamics remain largely absent from the current biodiversity monitoring framework. We present a working pipeline in which we operationalize a movement trait, maximum displacement, as a standardized metric for biodiversity monitoring. We first compiled, cleaned, and harmonized animal movement tracking data from 8,379 individuals representing 66 terrestrial mammal species across 62 countries. Then, we quantified 1-day and 10-day displacements at the individual level (n = 1,611,140 and n = 329,209, respectively). Finally, we examined how individual maximum displacement responds to the composition (i.e., amount, measured by settlement cover) and configuration (i.e., spatial arrangement, measured by settlement porosity) of settled landscapes, where human settlements represent impermeable movement barriers for terrestrial mammals. Our results showed that maximum displacement declined consistently with increasing amounts of settlement in a landscape. In addition, we found that maximum displacement decreased with decreasing settlement porosity across species and scales. At the 10-day scale, for example, displacements decreased by 31.1% with the loss of settlement porosity and by 30.8% with increasing settlement coverage. We also tested these responses under different measurements of the composition of settled landscapes, including the widely used human footprint index and human modification index, and our results remained consistent. Because animal movement is closely associated with ecosystem functions such as seed dispersal and nutrient transfer, the variation in maximum displacement can serve as an indicator for biodiversity changes in response to human pressure. Our results also provided global-scale empirical evidence that landscape configuration is as important as landscape composition in shaping ecological processes such as animal movement. Taken together, our study showed that maximum displacement is a useful movement trait that could be incorporated into indicator frameworks for biodiversity monitoring, especially as animal movement data continue to proliferate with the advancement of tracking technology.