The role of Megafauna in shaping ecosystems: insights into rewilding

VENI Project (N. 016.veni.181.031)

Funded by the Dutch Research Council (NWO)

Total budget = 249,900 Euros

Executive summary

Large-bodied mammals (megafauna) have experienced massive Pleistocenic extinctions and ongoing severe declines of extant species. These species exert strong effects in ecosystems, and their losses and decline triggered shifts in ecosystem equilibria. Rewilding is a new conservation vision that proposes several approaches including the reintroduction of megafauna to restore ecosystem functions. Yet our understanding on the ecological effects of megafauna is limited to a few studies from which it is hard to generalise, making the outcomes of rewilding actions uncertain. Macroecology is traditionally based on correlative approaches, but for a better understanding of macroecological processes and increase predictive power the use of process-based models has been invoked multiple times.

This project aims to forecast the effect of extinction and reintroduction of megafauna on ecosystem structure and stability, shifts in ecosystem equilibria, top-down/bottom-up regulation, and the emergence of migration in reintroduced megafauna with a process-based modelling approach. Process-based models are built upon our theoretical understanding of ecology and focus on the underlying processes driving the ecological patterns. Such an approach allows for an analysis of rewilding effects on various temporal and geographic scales and a wide range of community and environmental conditions. I will also specifically apply the model to a study site in Velebit, Croatia, where rewilding is currently being implemented. Here, I will estimate the effect of current hunting quotas and no-take areas, optimize megafauna reintroduction strategy, and investigate local migration emergence.

By employing a process-based ecosystem model, this project will allow for a deeper understanding that goes beyond the individual species level to enable general conclusions that are representative a broader range of ecological contexts and species. The results of my Veni-project will contribute to the further underpinning and optimization of management strategies of rewilding initiatives.

Main collaborators

Selwyn Hoeks (Radboud University)

Marta Cimatti (Sapienza University)

Mark Huijbregts (Radboud University)

Mike Harfoot (WCMC)

Jens-Christian Svenning (Aarhus University)

Rewilding Europe

Research outputs

Hoeks, S., Huijbregts, M. A., Busana, M., Harfoot, M. B., Svenning, J. C., & Santini, L. (2020). Mechanistic insights into the role of large carnivores for ecosystem structure and functioning. Ecography, 43(12), 1752-1763.

Cimatti M., Ranc N., Benítez-López A., Maiorano L., Boitani L., Cagnacci F., Čengić M., Ciucci P., Huijbregts M.A.J., Krofel M., López Bao J., Selva N., Andren H., Bautista C., Cirovic D., Hemmingmoore H., Reinhardt I., Marenče M., Mertzanis Y., Pedrotti L., Trbojević I., Zetterberg A., Zwijacz-Kozica T., Santini L. Large carnivore expansion in Europe is associated with human population density and land cover changes. Diversity and Distributions, ACCEPTED

Hoeks S., Tucker M.A., Huijbregts, M.A.J., Harfoot M.B.J., Bithell M., Santini L. MadingleyR: an R package for increased accessibility, flexibility and reproducibility of mechanistic ecosystem modelling. Under review in Global Ecology and Biogeography

Santini L., et al. Simulating megafauna reintroduction in Europe: insights into trophic rewilding. In preparation