Elephant rewilding affects landscape openness and fauna habitat across a 92-year period.

Trophic rewilding aims to promote biodiverse self-sustaining ecosystems through the restoration of ecologically important taxa and the trophic interactions and cascades they propagate. How rewilding effects manifest across broad temporal scales will determine ecosystem states; however, our understanding of post-rewilding dynamics across longer time-periods is limited. Here we show that the restoration of a megaherbivore, the African savannah elephant (Loxodonta africana), promotes landscape openness (i.e. various measures of vegetation composition / complexity) and modifies fauna habitat, and that these effects continue to manifest up to 92-years post-reintroduction. We conducted a space-for-time floristic survey and assessment of 17 habitat attributes (e.g. floristic diversity and cover, ground wood, tree hollows) across five comparable nature reserves in South African savannah where elephants were reintroduced between 1927 - 2003, finding that elephant reintroduction time was positively correlated with landscape openness and some habitat attributes (e.g. large-sized tree hollows), but negatively associated with others (e.g. large-sized coarse woody debris). We then indexed elephant site-occurrence between 2006 - 2018 using telemetry data and found positive associations between site-occurrence and woody plant densities. Taken along-side the longer-term space-for-time survey, this suggests that elephants are attracted to dense vegetation in the short-term, and that this behavior increases landscape openness in the long-term. Our results suggest that trophic rewilding with elephants helps promote a semi-open ecosystem structure of high importance for Africa biodiversity. More generally, our results suggest that megafauna restoration provides a promising tool to curb Earth's recent ecological losses and highlights the importance of considering long-term ecological responses when designing and managing rewilding projects.