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

Abstract

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 after reintroduction.

Late‐Quaternary megafauna extinctions have strongly reduced mammalian vegetation consumption

“…Large herbivores can have major direct structural effects on vegetation (e.g. elephants knock trees over Asner & Levick, 2012; Gordon et al, 2023), but are also important in more subtle ways. Importantly, key ecological effects of herbivores exhibit strong allometric scaling, for example, nutrient and seed dispersal (Doughty et al, 2013; Fricke et al, 2022; Wolf et al, 2013), nutrient stoichiometry in dung (Le Roux et al, 2020), and vegetation consumption and ecosystem energy flux (Enquist et al, 2020; Pedersen et al, 2017).…”

Feedback loops between 3D vegetation structure and ecological functions of animals

“…Assisted reintroductions of species to landscapes can also promote change-inducing feedback that recovers past vegetation structure. One example from a South African savanna showed how elephant browsing behaviour in densely vegetated areas contributed to an eventual increase in landscape openness through a change-inducing feedback loop (Gordon et al, 2023).…”

“…In this example, reintroduced African savanna elephants are attracted to dense vegetation, where they browse and knock down trees, creating more open vegetation structure and attracting other herbivores, which contribute to further increases in vegetation openness by browsing and grazing in areas where they can easily find forage and detect predators. This figure draws from many examples in African savannas, with the examples in Steps 1 and 6 from inside and outside the Nkuhlu herbivore exclosure in Kruger National Park, South Africa; the example in Step 2 of rewilding in South Africa from Gordon et al (2023). Photo: Bernard Dupont, CC BY‐SA 2.0 via Wikimedia Commons; elephant tracking data in South Africa in Step 3 from Thaker et al (2019); tree density data in Step 4 from Gordon et al (2023) and viewshed in Step 5 from (Davies, Tambling, et al, 2016).…”

“…This figure draws from many examples in African savannas, with the examples in Steps 1 and 6 from inside and outside the Nkuhlu herbivore exclosure in Kruger National Park, South Africa; the example in Step 2 of rewilding in South Africa from Gordon et al (2023). Photo: Bernard Dupont, CC BY‐SA 2.0 via Wikimedia Commons; elephant tracking data in South Africa in Step 3 from Thaker et al (2019); tree density data in Step 4 from Gordon et al (2023) and viewshed in Step 5 from (Davies, Tambling, et al, 2016).…”

“…Ecological functions of animals are often recognized in conservation strategies for their ability to sustain ecosystems or restore them to an earlier state of structure and functioning (Enquist et al, 2020; Gordon et al, 2023; Malhi et al, 2022). Some conservation strategies have benefited from acknowledging components of a feedback loop between vegetation structure and animal ecological roles, such as how landscapes can change after reintroducing animals (Gordon et al, 2023). Tools and methods now exist to describe animal–vegetation feedback loops and their importance for ecosystem functioning, with broad applications for conservation.…”