Impacts of top predators and humans on the mammal communities of recovering temperate forest regions

Wen She; Jiayin Gu; Marcel Holyoak; Chuan Yan; Jinzhe Qi; Xinru Wan; Shuyan Liu; Lei Xu; Nathan James Roberts; Zhibin Zhang; Guangshun Jiang

doi:10.1016/j.scitotenv.2022.160812

Impacts of top predators and humans on the mammal communities of recovering temperate forest regions

Sci Total Environ. 2023 Mar 1:862:160812. doi: 10.1016/j.scitotenv.2022.160812. Epub 2022 Dec 7.

Authors

Wen She¹, Jiayin Gu¹, Marcel Holyoak², Chuan Yan³, Jinzhe Qi¹, Xinru Wan⁴, Shuyan Liu¹, Lei Xu⁵, Nathan James Roberts¹, Zhibin Zhang⁴, Guangshun Jiang⁶

Affiliations

¹ Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China; Northeast Asia Biodiversity Research Center, Northeast Forestry University, Harbin 150040, China.
² Department of Environmental Science and Policy, University of California, Davis, CA 95616, USA.
³ Institute of Innovation Ecology, Lanzhou University, Lanzhou 730000, China.
⁴ State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
⁵ Vanke School of Public Health, Tsinghua University, Beijing 100083, China.
⁶ Feline Research Center of National Forestry and Grassland Administration, College of Wildlife and Protected Area, Northeast Forestry University, Harbin 150040, China; Northeast Asia Biodiversity Research Center, Northeast Forestry University, Harbin 150040, China. Electronic address: jgshun@126.com.

PMID: 36493822
DOI: 10.1016/j.scitotenv.2022.160812

Abstract

Top predators are important drivers in shaping ecological community structure via top-down effects. However, the ecological consequences and mechanisms of top predator loss under accelerated human impacts have rarely been quantitatively assessed due to the limited availability of long-term community data. With increases in top predator populations in northern China over the past two decades, forests with varying densities of top predators and humans provide an opportunity to study their ecological effects on mammal communities. We hypothesized a priori of conceptual models and tested these using structural equation models (SEMs) with multi-year camera trap data, aiming to reveal the underlying independent ecological effects of top predators (tigers, bears, and leopards) and humans on mammal communities. We used random forest models and correlations among species pairs to validate results. We found that top predator reduction could be related to augmented populations of large ungulates ("large ungulate release") and mesopredators ("mesopredator release"), consistent with observations of mammal communities in other ecosystems. Additionally, top predator reduction could be related to reduced small mammal abundance. Hierarchical SEMs identified three bottom-up pathways from forest quality to human activities, large ungulates, and some small mammals, and five top-down pathways from human activities and top predators to some small mammals, large ungulates, and mesopredators. Furthermore, our results suggest that humans showed predominant top-down effects on multiple functional groups, partially replacing the role of top predators, rather than be mediated by them; effects of humans and top predators appeared largely independent. Effects of humans on top predators were non-significant. This study provides novel insights into the effects of top predators and humans as super-predators on mammal communities in forest ecosystems and presents cues of bottom-up effects that can be translated into actionable management plans for improving forest quality, thereby supporting top predator recovery and work/life activities of local people.

Keywords: Bottom-up effects; Co-existence; Ecological communities; Forest quality; Top-down effects.

MeSH terms

Animals
Ecosystem*
Food Chain
Humans
Mammals
Models, Theoretical
Population Dynamics
Predatory Behavior*