Woody vegetation dynamics in a protected African savanna: insights from vegetation resurvey of the Gonarezhou National Park, Zimbabwe

Aims: This study assessed changes in woody vegetation cover, richness, diversity, and species composition in GonarezhouNational Park (GNP) between 2010 and 2023, focusing on the impacts of fire and elephants. Analyses were conducted for theentire park and its main vegetation types and ecoregions.Location: GNP is located in southern Zimbabwe, bordering Mozambique, covering approximately 5000 km 2 .Methods: In 2010, 313 sampling areas were surveyed, and a resurvey was conducted in 2022/2023 using a plotless method. Foreach area, woody species cover was recorded in four height classes. Indices for total woody cover, species richness, diversity(Shannon), and evenness (Pielou) were calculated for both surveys across the park, ecoregions, and vegetation types. Differencesbetween surveys were analyzed with paired t-tests. Species composition changes were analyzed using NMDS and PERMANOVA,while the effects of fire frequency, slope, and distance from rivers on species composition were tested with a mixed linear model.The change in dominant species occurrence was also examined.Results: Species richness significantly declined, with no changes in woody vegetation cover, diversity, or evenness, except in thealluvial ecoregion, where diversity decreased. Changes across height layers revealed increased richness and diversity in the < 1 mlayer and declines in the 1–3 m and 3–5 m layers. Species composition changes were significant across ecoregions and influencedby fire frequency. A decrease in dominant tree species was observed, varying by species' resilience to current pressures.Conclusions: GNP 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 man-agement system, and the creation of ecological corridors in the Greater Limpopo Transfrontier Conservation Area to facilitatethe movement of elephants