1
|
Yang Y, Zhao Y, Stidham TA, Liu X, Zhu X, Li B, Zhang L, Ni X, Si X. Uncovering widespread Anthropocene dietary shifts in Chinese large mammalian herbivores. Ecol Lett 2024; 27:e14343. [PMID: 38069561 DOI: 10.1111/ele.14343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 01/31/2024]
Abstract
The Anthropocene's human-dominated habitat expansion endangers global biodiversity. However, large mammalian herbivores experienced few extinctions during the 20th century, hinting at potentially overlooked ecological responses of a group sensitive to global change. Using dental microwear as a proxy, we studied large herbivore dietary niches over a century across mainland China before (1880s-1910s) and after (1970s-1990s) the human population explosion. We uncovered widespread and significant shifts (interspecific microwear differences increased and intraspecific microwear dispersion expanded) within dietary niches linked to geographical areas with rapid industrialization and population growth in eastern China. By contrast, in western China, where human population growth was slower, we found no indications of shifts in herbivore dietary niches. Further regression analysis links the intensity of microwear changes to human land-use expansion. These analyses highlight dietary adjustments of large herbivores as a likely key factor in their adaptation across a century of large-scale human-driven changes.
Collapse
Affiliation(s)
- Yangheshan Yang
- Zhejiang Zhoushan Archipelago Observation and Research Station, Institute of Eco-Chongming, Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Yuhao Zhao
- Zhejiang Zhoushan Archipelago Observation and Research Station, Institute of Eco-Chongming, Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Thomas A Stidham
- Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xiangxu Liu
- Zhejiang Zhoushan Archipelago Observation and Research Station, Institute of Eco-Chongming, Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Xichao Zhu
- National Animal Collection Resource Center, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Bicheng Li
- Shanghai Natural History Museum (Branch of Shanghai Science & Technology Museum), Shanghai, China
| | - Lixun Zhang
- School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
- Yuzhong Mountain Ecosystems Observation and Research Station, Lanzhou University, Lanzhou, Gansu, China
| | - Xijun Ni
- Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xingfeng Si
- Zhejiang Zhoushan Archipelago Observation and Research Station, Institute of Eco-Chongming, Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| |
Collapse
|
2
|
Pringle RM, Abraham JO, Anderson TM, Coverdale TC, Davies AB, Dutton CL, Gaylard A, Goheen JR, Holdo RM, Hutchinson MC, Kimuyu DM, Long RA, Subalusky AL, Veldhuis MP. Impacts of large herbivores on terrestrial ecosystems. Curr Biol 2023; 33:R584-R610. [PMID: 37279691 DOI: 10.1016/j.cub.2023.04.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Large herbivores play unique ecological roles and are disproportionately imperiled by human activity. As many wild populations dwindle towards extinction, and as interest grows in restoring lost biodiversity, research on large herbivores and their ecological impacts has intensified. Yet, results are often conflicting or contingent on local conditions, and new findings have challenged conventional wisdom, making it hard to discern general principles. Here, we review what is known about the ecosystem impacts of large herbivores globally, identify key uncertainties, and suggest priorities to guide research. Many findings are generalizable across ecosystems: large herbivores consistently exert top-down control of plant demography, species composition, and biomass, thereby suppressing fires and the abundance of smaller animals. Other general patterns do not have clearly defined impacts: large herbivores respond to predation risk but the strength of trophic cascades is variable; large herbivores move vast quantities of seeds and nutrients but with poorly understood effects on vegetation and biogeochemistry. Questions of the greatest relevance for conservation and management are among the least certain, including effects on carbon storage and other ecosystem functions and the ability to predict outcomes of extinctions and reintroductions. A unifying theme is the role of body size in regulating ecological impact. Small herbivores cannot fully substitute for large ones, and large-herbivore species are not functionally redundant - losing any, especially the largest, will alter net impact, helping to explain why livestock are poor surrogates for wild species. We advocate leveraging a broad spectrum of techniques to mechanistically explain how large-herbivore traits and environmental context interactively govern the ecological impacts of these animals.
Collapse
Affiliation(s)
- Robert M Pringle
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
| | - Joel O Abraham
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - T Michael Anderson
- Department of Biology, Wake Forest University, Winston Salem, NC 27109, USA
| | - Tyler C Coverdale
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA; Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Andrew B Davies
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | | | | | - Jacob R Goheen
- Department of Zoology & Physiology, University of Wyoming, Laramie, WY 82072, USA
| | - Ricardo M Holdo
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - Matthew C Hutchinson
- Department of Life & Environmental Sciences, University of California Merced, Merced, CA 95343, USA
| | - Duncan M Kimuyu
- Department of Natural Resources, Karatina University, Karatina, Kenya
| | - Ryan A Long
- Department of Fish and Wildlife Sciences, University of Idaho, Moscow, ID 83844, USA
| | - Amanda L Subalusky
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Michiel P Veldhuis
- Institute of Environmental Sciences, Leiden University, 2333 CC Leiden, The Netherlands
| |
Collapse
|
3
|
Phillips EM, Pringle RM. Ecology: How mesopredators run with the big dogs. Curr Biol 2023; 33:R197-R199. [PMID: 36917945 DOI: 10.1016/j.cub.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Food webs are indispensable maps of community organization, but most are crudely drawn - an inconvenient truth that ecologists must confront. A new DNA metabarcoding study quantifies predator-prey interactions and ecological-network structure with long-overdue precision, supplying insight into how large and small carnivores coexist.
Collapse
Affiliation(s)
- Erin M Phillips
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Robert M Pringle
- Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
| |
Collapse
|
4
|
Lu Q, Cheng C, Xiao L, Li J, Li X, Zhao X, Lu Z, Zhao J, Yao M. Food webs reveal coexistence mechanisms and community organization in carnivores. Curr Biol 2023; 33:647-659.e5. [PMID: 36669497 DOI: 10.1016/j.cub.2022.12.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 11/11/2022] [Accepted: 12/20/2022] [Indexed: 01/20/2023]
Abstract
Globally, massive carnivore guild extirpations have led to trophic downgrading and compromised ecosystem services. However, the complexity of multi-carnivore food webs complicates accurate identification of species interactions and community organization. Here, we used fecal DNA metabarcoding to investigate three communities that together encompass eight large- and meso-carnivore species and their 44 prey taxa of the Qinghai-Tibet Plateau (QTP), one of the last places on Earth that still harbors intact carnivore assemblages. Quantitative food-web analyses revealed pronounced interspecific variations in the carnivores' prey compositions and dietary partitioning both between and within guilds. Additionally, body masses of the carnivores and their prey exhibited consistent hump-shaped correlations across communities. Overall, differences in prey diversity, size category, and proportional utilization among the carnivore species result in trophic niche segregation that likely promotes carnivore coexistence in the harsh QTP environment. Network structure analyses detected significant modularity in all food webs but nestedness in only one. Furthermore, network characterization identified pikas (Ochotona spp.), bharal (Pseudois nayaur), and domestic yak (Bos grunniens) as potential keystone prey across the areas. Our results paint a holistic and detailed picture of the QTP carnivore assemblages' trophic networks and demonstrate that the combined use of the molecular dietary approach and network analysis can generate structural insights into carnivore coexistence and can identify functionally important species in complex communities. Such knowledge can help safeguard carnivore guild integrity and enhance community resilience to environmental perturbations in the sensitive QTP ecosystems.
Collapse
Affiliation(s)
- Qi Lu
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Chen Cheng
- Center for Nature and Society, School of Life Sciences, Peking University, Beijing 100871, China; Shan Shui Conservation Center, Beijing 100871, China
| | - Lingyun Xiao
- School of Life Sciences, Peking University, Beijing 100871, China; Department of Health and Environmental Sciences, Xi'an Jiaotong Liverpool University, Suzhou, Jiangsu 215123, China
| | - Juan Li
- School of Life Sciences, Peking University, Beijing 100871, China; Department of Health and Environmental Sciences, Xi'an Jiaotong Liverpool University, Suzhou, Jiangsu 215123, China
| | - Xueyang Li
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Xiang Zhao
- Shan Shui Conservation Center, Beijing 100871, China
| | - Zhi Lu
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China; Center for Nature and Society, School of Life Sciences, Peking University, Beijing 100871, China; Shan Shui Conservation Center, Beijing 100871, China
| | - Jindong Zhao
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Meng Yao
- School of Life Sciences, Peking University, Beijing 100871, China; Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
| |
Collapse
|
5
|
Walker RH, Hutchinson MC, Potter AB, Becker JA, Long RA, Pringle RM. Mechanisms of individual variation in large herbivore diets: Roles of spatial heterogeneity and state-dependent foraging. Ecology 2023; 104:e3921. [PMID: 36415899 PMCID: PMC10078531 DOI: 10.1002/ecy.3921] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 11/24/2022]
Abstract
Many populations of consumers consist of relatively specialized individuals that eat only a subset of the foods consumed by the population at large. Although the ecological significance of individual-level diet variation is recognized, such variation is difficult to document, and its underlying mechanisms are poorly understood. Optimal foraging theory provides a useful framework for predicting how individuals might select different diets, positing that animals balance the "opportunity cost" of stopping to eat an available food item against the cost of searching for something more nutritious; diet composition should be contingent on the distribution of food, and individual foragers should be more selective when they have greater energy reserves to invest in searching for high-quality foods. We tested these predicted mechanisms of individual niche differentiation by quantifying environmental (resource heterogeneity) and organismal (nutritional condition) determinants of diet in a widespread browsing antelope (bushbuck, Tragelaphus sylvaticus) in an African floodplain-savanna ecosystem. We quantified individuals' realized dietary niches (taxonomic richness and composition) using DNA metabarcoding of fecal samples collected repeatedly from 15 GPS-collared animals (range 6-14 samples per individual, median 12). Bushbuck diets were structured by spatial heterogeneity and constrained by individual condition. We observed significant individual-level partitioning of food plants by bushbuck both within and between two adjacent habitat types (floodplain and woodland). Individuals with home ranges that were closer together and/or had similar vegetation structure (measured using LiDAR) ate more similar diets, supporting the prediction that heterogeneous resource distribution promotes individual differentiation. Individuals in good nutritional condition had significantly narrower diets (fewer plant taxa), searched their home ranges more intensively (intensity-of-use index), and had higher-quality diets (percent digestible protein) than those in poor condition, supporting the prediction that animals with greater endogenous reserves have narrower realized niches because they can invest more time in searching for nutritious foods. Our results support predictions from optimal foraging theory about the energetic basis of individual-level dietary variation and provide a potentially generalizable framework for understanding how individuals' realized niche width is governed by animal behavior and physiology in heterogeneous landscapes.
Collapse
Affiliation(s)
- Reena H Walker
- Department of Fish and Wildlife Sciences, University of Idaho, Moscow, Idaho, USA
| | - Matthew C Hutchinson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Arjun B Potter
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Justine A Becker
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA.,Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, USA
| | - Ryan A Long
- Department of Fish and Wildlife Sciences, University of Idaho, Moscow, Idaho, USA
| | - Robert M Pringle
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| |
Collapse
|
6
|
Lintulaakso K, Tatti N, Žliobaitė I. Quantifying mammalian diets. Mamm Biol 2022. [DOI: 10.1007/s42991-022-00323-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
AbstractWe propose a quantitative approach for categorising mammalian diets based on the taxonomy of food items and parts consumed (the form of food). Our analysis covers 82% of the mammalian species alive today. The diet information comes from different data sources—textbooks, datasets and peer-reviewed literature and includes a transformation of narrative quantitative data into qualitative data. We link a database on nutrient composition of diet items of the quantitative diet data and analyse the distribution of macronutrients of diets across taxonomic groups and map them to the dental morphology of the eaters. The results show associations between dental complexity and the concentrations of some nutrients. Our analysis highlights omnivory as a multi-faceted concept—there are many kinds of omnivores within the dietary space we report. The developed dataset and the proposed approach relating the chemical composition of diets offers a basis for future comparative studies of living and fossil mammals. With this study, we make the accompanying large-scale dietary data publicly available online (https://www.mammalbase.net).
Collapse
|
7
|
The generality of cryptic dietary niche differences in diverse large-herbivore assemblages. Proc Natl Acad Sci U S A 2022; 119:e2204400119. [PMID: 35994662 PMCID: PMC9436339 DOI: 10.1073/pnas.2204400119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Ecological niche differences are necessary for stable species coexistence but are often difficult to discern. Models of dietary niche differentiation in large mammalian herbivores invoke the quality, quantity, and spatiotemporal distribution of plant tissues and growth forms but are agnostic toward food plant species identity. Empirical support for these models is variable, suggesting that additional mechanisms of resource partitioning may be important in sustaining large-herbivore diversity in African savannas. We used DNA metabarcoding to conduct a taxonomically explicit analysis of large-herbivore diets across southeastern Africa, analyzing ∼4,000 fecal samples of 30 species from 10 sites in seven countries over 6 y. We detected 893 food plant taxa from 124 families, but just two families-grasses and legumes-accounted for the majority of herbivore diets. Nonetheless, herbivore species almost invariably partitioned food plant taxa; diet composition differed significantly in 97% of pairwise comparisons between sympatric species, and dissimilarity was pronounced even between the strictest grazers (grass eaters), strictest browsers (nongrass eaters), and closest relatives at each site. Niche differentiation was weakest in an ecosystem recovering from catastrophic defaunation, indicating that food plant partitioning is driven by species interactions, and was stronger at low rainfall, as expected if interspecific competition is a predominant driver. Diets differed more between browsers than grazers, which predictably shaped community organization: Grazer-dominated trophic networks had higher nestedness and lower modularity. That dietary differentiation is structured along taxonomic lines complements prior work on how herbivores partition plant parts and patches and suggests that common mechanisms govern herbivore coexistence and community assembly in savannas.
Collapse
|