Advancing Conservation through Ecological Restoration and the Efficacy of Multi-Trophic Rewilding in the Yellowstone Ecosystem

Abstract

The Yellowstone Northern Range can be used to produce a long-term and critical dataset on the effectiveness of multi-trophic rewilding, or reintroduction of the gray wolf (Canis lupus) in ecosystem recovery. The subsequent troic cascade in 1995, with the wolf coming back, essentially rearranged the ecosystem, starting to not be a predator-prey scenario, but to regain the biodiversity and the complexity of habitats. The paper evaluates the effects of the cascade, which shows the extensive influence it has on the riparian structure and the most important wildlife species. The increase of the hyper-abundant elk (Cervus elaphus) population caused behavioral changes, which reduced the level of browsing pressure, which caused a substantial recovery of vital riparian vegetation such as willows (Salix spp.) and shrubs that produced berries. In particular, the authors recorded a significant rise in the heights of the willow stems, with the majority exceeding 200 cm (this height is beyond the reach of the elk) after the reintroduction, unlike the levels before 1995, when it was less than 50 cm on average. The paper examines the effects of the cascade, which has shown a significant influence on par with the structure of the riparian zone and major wildlife species between 1995 and the current time. This vegetation recovery directly enabled the reintroduction of the beaver (Castor canadensis), an ecosystem engineer by building wetlands, but indirectly benefited the omnivorous grizzly bear (Ursus arctos horribilis) by increasing important carrion food sources and essential fruit sources for pre-hibernation foraging. The Yellowstone experience demonstrates that recovery of the entire suite of large carnivores can trigger a self-perpetuation process of ecological recovery, which re-establishes complex interactions to climb a conservation agenda.