Understanding the scale of elephant effects for conservation management: integrating woody shrub responses in succulent thicket, South Africa

The conservation management of elephant focuses on identifying and mitigating the extent and intensity of effects on biodiversity. However, these concepts are poorly integrated in empirical studies, which confound our understanding of the scale of the impacts. Our study quantifies > 50 years of elephant effects on the canopy shrubs (a key functional guild) of the Addo Elephant National Park, South Africa, contrasting the impacts between elements of the community; i.e. from community composition and structure, to the structure of individual canopy species. We show the vulnerability of succulent thicket to being transformed as the accumulated influences of elephant reduce community composition and structure, and consequently ecological functioning. The pattern of transformation is similar to that caused by domestic herbivores, which leads us to predict that elephant will eventually bring about landscape-level degradation and a significant loss of biodiversity. While we expected the influences on the canopy species to provide insight into these community responses, we demonstrate an uneven distribution of impacts between these elements of biodiversity. This implies that the canopy dominants might not be useful indicators of community change in thicket, a pattern that is likely repeated among the canopy trees of savanna systems. Our findings have important implications for monitoring, andsuggest that predicting the impacts requires a broader integrated understanding of the mechanisms driving the changes between elements of biodiversity, at various spatial and temporal scales. Thus, the effective conservation management of elephant can only be achieved through the careful, scientific design of monitoring programmes