Exploring a natural baseline for large-herbivore biomass in ecological restoration

Fløjgaard, Camilla, Pedersen, Pil Birkefeldt Møller, Sandom, Christopher J, Svenning, Jens-Christian and Ejrnæs, Rasmus (2022) Exploring a natural baseline for large-herbivore biomass in ecological restoration. Journal of Applied Ecology, 59 (1). pp. 18-24. ISSN 0021-8901

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Abstract

1 - Large herbivores provide key ecosystem processes, but have experienced massive historical losses and are under intense pressure, leaving current ecosystems with dramatically simplified faunas relative to the long-term evolutionary norm. Hampered by a shifting baseline, natural levels of large-herbivore biomass are poorly understood and seldom targeted. This ‘Decade of ecosystem restoration’ calls for evidence-based targets for restoring the natural diversity and biomass of large herbivores.

2 - We apply the scaling of the consumer–producer relationship to a global dataset of large-herbivore density in natural areas. The analyses reveal that African ecosystems generally have much higher large-herbivore biomass and also the strongest consumer–producer relationship. For Europe, Asia and South America, there are no significant relationships with primary productivity indicative of impoverished faunas. Compared to expectations from the African scaling relation, large-herbivore biomass in ecosystems outside Africa is considerably lower than expected.

3 - Synthesis and applications. Ecological restoration and rewilding entail restoration of a natural grazing process. Our findings indicate that many nature reserves are depleted in large-herbivore biomass, judged from their primary productivity. Meanwhile, overexploitation by seasonal livestock grazing takes place in other areas. It is thus difficult, but urgent, to reach scientific consensus regarding a natural baseline for large-herbivore biomass. Until such agreement has been reached, we recommend to manage, or rewild, large herbivores in year-round near-natural grazing and without predefined density targets, but following natural and fluctuating resource availability with minimal management intervention. The establishment of experimental rewilding sites with reactive herbivore management is needed to further advance our understanding of natural grazing density.

Item Type: Article
Keywords: Herbivore, Mammal, Restoration, Rewilding, Megafauna, Megaherbivores
Schools and Departments: School of Life Sciences > Evolution, Behaviour and Environment
SWORD Depositor: Mx Elements Account
Depositing User: Mx Elements Account
Date Deposited: 18 Oct 2021 09:03
Last Modified: 22 Mar 2022 09:30
URI: http://sro.sussex.ac.uk/id/eprint/102328

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