Space use by African savanah elephants and their ranging patterns beyond the protected area boundaries

Protected areas in southern Africa provide refuge to important megafauna such as the savannah elephant (Loxodonta africana). Sections of these protected areas are often transfrontier conservation complexes, whose objective is to facilitate historic patterns of animal dispersal and knowledge of megafauna home ranges, habitat use, and dispersal in key protected areas such as Gonarezhou National Park can inform vital decision-making for the global conservation goals of African elephants. This study investigated the seasonal and sex differences in elephants' home range sizes, home range overlap, and their interaction with environmental variables, using location data derived from satellite collars fitted on 26 savannah elephants from 2016 – 2022 in Gonarezhou National Park, Zimbabwe. Furthermore, the study investigated the extent to which male and female elephants used landscapes outside the Gonarezhou National Park, focusing on the effects of season and landcover types on the likelihood of dispersal outside the protected area. It also examined the impact of time of day on elephant activity and landscape use. Additionally, the study evaluated behavioural differences among elephants when ranging in non-protected areas with varying human densities. The study also assessed changes in woody vegetation cover, richness, diversity, and species composition in Gonarezhou National Park between 2010 and 2023, focusing on the impacts of fire and elephants. Changes in species composition were assessed for relevant environmental variables such as fire frequency, slope, and distance from the permanent rivers, and analyses were conducted for the entire park and its main vegetation types and ecoregions. Differences in the size of home ranges between sexes in all seasons were not significant. Both male and female elephants had high site fidelity, retaining 60% of their home ranges between consecutive seasons, and only females, possibly tracking forage quality, showed reduced overlap of home ranges between the hot dry and hot wet seasons. Male elephants preferred vegetation types dominated by Colophospermum mopane, whereas females used more diverse upland vegetation types, showing a preference for higher elevations than males across all seasons. The results showed that male elephants were more likely to move outside the GNP than females, dispersing at greater distances than females. Male elephants moved as far as 60 km from Gonarezhou, while females typically did not disperse further than 15 km. Most movement outside protected area boundaries was during the cool-dry season (April to July). Male and female elephants returned to the Gonarezhou National Park during the hot-wet season (December to March). When outside the Gonarezhou National Park, male elephants preferred forested land cover types, whilst females remained in shrublands. Collared elephants avoided areas adjacent to the Gonarezhou National Park where human population densities were high. Although surface water may also play a role in elephant movement, there were no reliable data to validate this in this study. The results denoted some use of areas neighbouring Gonarezhou National Park by elephants, particularly in Mozambique, but not widespread dispersal. Within the Gonarezhou National Park, plant species richness significantly declined, with no changes in woody vegetation cover, diversity, or evenness, except in the alluvial ecoregion, where diversity decreased. Changes across height layers revealed increased richness and diversity in the <1m layer, and declines in the 1-3m and 3-5m layers. Species composition changes were significant across ecoregions and influenced by fire frequency. A decrease in dominant tree species was observed, varying by species' resilience to the current elephant pressure. Currently, the elephant population in GNP has a growth rate of about 6% per annum, and considering the global conservation status of African savannah elephants, dispersal to other less populated areas would be ideal and the best option for managing this elephant population. The results showed that Gonarezhou National Park is undergoing simplification in woody vegetation, likely due to the combined effects of elephants and fire. This is leading to shrubbier vegetation and changes in species composition, particularly in trees. To prevent further degradation, actions must be implemented, such as the use of individual protection systems from debarking, the development of a fire management system, and the creation of ecological corridors in the Greater Limpopo Transfrontier Conservation Area to facilitate the movement of elephants. Conservation planning in the region should consider immediate interventions for addressing barriers to the movement of elephants to Zinave and Banhine National Parks in Mozambique to avoid the risk of escalating fragmentation of the landscape. Additionally, the communal area linking Gonarezhou to Kruger National Park should be prioritised for conservation efforts and pilot projects to test the functionality of the corridor. In other areas where fences and human settlements restrict elephant movement, continuous monitoring of elephant space use is recommended, and research dynamics should be taken into account when developing site-specific elephant management plans.