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

Global Tiger Density Linked With Forest Carbon Stock, Top-Down and Bottom-Up

Tiger (Panthera tigris) survival, as apex predators in forest ecosystems, largely depends on abundant prey in healthy, intact forests. Because large herbivore prey are drivers of plant biomass, we reasoned that tiger distribution and density are probably also closely linked with forest carbon (C) stock, the management of which is critical for mitigating climate change. However, whether tigers exert top-down control of forest C stocks or are passive surrogate C indicators bottom-up is a salient unanswered question in conservation and management, particularly in trophic rewilding. Here, we compiled estimates of global tiger presence and density to test the top-down effects of tigers on forest C stocks and tiger-carbon relationships along a gradient from "empty forests" without tigers to "target state" ecosystems with tigers living at different abundances. Our results showed that tiger presence was associated with higher forest vegetation C stocks, lower C emissions, and higher C inputs globally. Top-down effects via ungulate biomass were stronger in less established forests. Furthermore, forest vegetation or soil C stocks increased with tiger density or reached tiger-carbon peaks in four forest habitat types covering most of the tiger range. Our findings reveal that tigers, represented by their presence and density, are both an indicator and a driver of forest ecosystem C stocks, depending on underlying ecological conditions, and could safeguard forests against future C emissions and improve our understanding of climate-C cycle feedback.

The Spatial Relationship Between Two Sympatric Pheasant Species and Various Human Disturbance Activities

Establishing and managing nature reserves to mitigate wildlife habitat loss and fragmentation is challenging, particularly in the face of increasing human activity. To understand how wildlife coexists in environments affected by anthropogenic disturbances, we conducted a 19-month survey examining the Reeves's pheasant (Syrmaticus reevesii) and Koklass pheasant (Pucrasia macrolopha) in the Anhui Tianma National Nature Reserve, China. Previous studies of large terrestrial birds focused primarily on livestock impacts, with less attention given to other human activities. We used occupancy models and performed daytime activity rhythm analysis based on camera trap data to examine the spatiotemporal responses of these species to human activities, livestock, and domestic dogs. The results showed that human disturbance activities within the reserve impact the distribution patterns of Reeves's pheasant and Koklass pheasant, but the effect was not significant. In high-disturbance environments, both species adjusted their activity times to avoid direct or indirect interactions with humans, livestock, and dogs. These findings provide insights for replanning core and creation of buffer zones within the reserve and have broader implications for conservation strategies in similar habitats. Our study suggests that well-designed conservation objectives can balance species protection with sustainable human presence.

Multitrophic Diversity of the Biotic Community Drives Ecosystem Multifunctionality in Alpine Grasslands

Biodiversity and ecosystem multifunctionality are currently hot topics in ecological research. However, little is known about the role of multitrophic diversity in regulating various ecosystem functions, which limits our ability to predict the impact of biodiversity loss on human well-being and ecosystem multifunctionality. In this study, multitrophic diversity was divided into three categories: plant, animal, and microbial communities (i.e., plant diversity, rodent diversity, and bacterial and fungal diversity). Also, 15 ecosystem functions were divided into four categories-water conservation, soil fertility, nutrient cycling and transformation, and community production-to evaluate the significance of biotic and abiotic variables in maintaining ecosystem multifunctionality. Results indicated that species diversity at multiple trophic levels had a greater positive impact on ecosystem multifunctionality than species diversity at a single trophic level. Notably, the specific nature of this relationship depended on the niche breadths of plants, indicating that plants played a key role in linking above and belowground trophic levels. Abiotic factors such as altitude and pH directly acted on ecosystem multifunctionality and could explain changes in ecosystem functions. Overall, our study offers valuable insights into the critical role of multitrophic species diversity in preserving ecosystem multifunctionality within alpine grassland communities, as well as strong support for the importance of biodiversity protection.

Three-dimensional forest foodscape in large herbivores' habitat based on UAV with LiDAR detection

With the development of artificial intelligence, the integration of LiDAR technologies and foodscape theories to study wildlife habitat, nutritional ecology, species coexistence, and other existing hot and difficult issues would become an international frontier in the field of wildlife habitat ecology and management.