American Naturalist最新文献_第4页

Family Matters: Linking Population Growth, Kin Interactions, and African Elephant Social Groups. 家庭问题：连接人口增长、亲缘关系和非洲象社会群体。

IF 2.4 2区环境科学与生态学

American Naturalist Pub Date : 2025-01-01 Epub Date: 2024-11-18 DOI: 10.1086/733181

Jasper C Croll, Hal Caswell

{"title":"Family Matters: Linking Population Growth, Kin Interactions, and African Elephant Social Groups.","authors":"Jasper C Croll, Hal Caswell","doi":"10.1086/733181","DOIUrl":"10.1086/733181","url":null,"abstract":"AbstractIn many species, individuals are embedded in a network of kin with whom they interact. Interactions between kin can affect survival and fertility rates and thus the life history of individuals. These interactions indirectly affect both the network of kin and the dynamics of the population. In this way, a nonlinear feedback between the kin network and individual vital rates emerges. We describe a framework for integrating these kin interactions into a matrix model by linking the individual kin network to a matrix model. We demonstrate the use of this framework for African elephant populations under varying poaching pressure. For this example, we incorporate effects of the maternal presence and matriarchal age on juvenile survival and effects of the presence of a sister on young female fecundity. We find that the feedback resulting from the interactions between family members shifts and reduces the expected kin network. The reduction in family size and structure severely reduces the positive effects of family interactions, leading to an additional decrease in population growth rate on top of the direct decrease due to the additional mortality. Our analysis provides a framework that can be applied to a wide range of social species.","PeriodicalId":50800,"journal":{"name":"American Naturalist","volume":"205 1","pages":"E1-E15"},"PeriodicalIF":2.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142883415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Shifting Precipitation Regimes Influence Optimal Germination Strategies and Population Dynamics in Bet-Hedging Desert Annuals. 降水变化对荒漠一年生植物最佳发芽策略和种群动态的影响

IF 2.4 2区环境科学与生态学

American Naturalist Pub Date : 2025-01-01 Epub Date: 2024-11-18 DOI: 10.1086/733105

William S Cuello, Sebastian J Schreiber, Jennifer R Gremer, Pete C Trimmer, D Lawrence Venable, Andrew Sih

{"title":"Shifting Precipitation Regimes Influence Optimal Germination Strategies and Population Dynamics in Bet-Hedging Desert Annuals.","authors":"William S Cuello, Sebastian J Schreiber, Jennifer R Gremer, Pete C Trimmer, D Lawrence Venable, Andrew Sih","doi":"10.1086/733105","DOIUrl":"https://doi.org/10.1086/733105","url":null,"abstract":"AbstractClimate change will affect both the mean and the variability in environmental conditions and may have major negative impacts on population densities in the future. For annual plants that already live in an extreme environment like the Sonoran Desert, keeping a fraction of their seeds dormant underground (for possibly years at a time) is critical to survive. Here, we consider how this form of bet hedging (i.e., delayed germination) for 10 Sonoran Desert annuals mediates responses to precipitation shifts. We use a demographic model parameterized with long-term field and precipitation data to explore how forecasted changes in precipitation impact annual plant species' population densities. We then examine how instantaneous evolution of optimal germination fractions in the shifted precipitation regimes bolsters population densities. Our results indicate that overall less rainfall and, to a lesser extent, increased variance in rainfall drive population levels down. Instantaneous evolution of optimal germination fractions in new regimes benefited species' populations only marginally, and only for small to moderate shifts in precipitation. Thus, even rapid evolution is unlikely to save populations experiencing larger shifts in precipitation. Finally, we predict that specialists that can capitalize on wet-year bonanzas or are water use efficient will be the most resilient to precipitation shifts as long as their seed survivorships are sufficiently high.","PeriodicalId":50800,"journal":{"name":"American Naturalist","volume":"205 1","pages":"55-75"},"PeriodicalIF":2.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142883384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Soilscapes of Mortality Risk Suggest a Goldilocks Effect for Overwintering Ectotherms. 死亡风险的土壤景观表明越冬变温动物的金发姑娘效应。

IF 2.4 2区环境科学与生态学

American Naturalist Pub Date : 2025-01-01 Epub Date: 2024-11-22 DOI: 10.1086/733183

Sarah A Waybright, Michael E Dillon

{"title":"Soilscapes of Mortality Risk Suggest a Goldilocks Effect for Overwintering Ectotherms.","authors":"Sarah A Waybright, Michael E Dillon","doi":"10.1086/733183","DOIUrl":"https://doi.org/10.1086/733183","url":null,"abstract":"AbstractChanging climates are driving population declines in diverse animals worldwide. Winter conditions may play an important role in these declines but are often overlooked. Animals must not only survive winter but also preserve body condition, a key determinant of growing season success. We hypothesized that ectotherms overwintering in soil face a trade-off between risks of cold damage (including freezing) near the surface and elevated energy use at deeper depths. To test this hypothesis, we developed landscapes of mortality risk across depth for overwintering bumble bee queens. These critical pollinators are in decline in part because of climate change, but little is known about how climate affects overwintering mortality. We developed a mechanistic modeling approach combining measurements of freezing points and the temperature dependence of metabolic rates with soil temperatures from across the United States to estimate mortality risk across depth under historic conditions and under several climate change scenarios. Under current conditions, overwintering queens face a Goldilocks effect: temperatures can be too cold at shallow depths because of substantial freezing risk but too hot at deep depths where they risk prematurely exhausting lipid stores. Models suggest that increases in mean temperatures and in seasonal and daily temperature variation will increase risk of overwinter mortality. Better predictions of effects of changing climate on dormant ectotherms require more measurements of physiological responses to temperature during dormancy across diverse taxa.","PeriodicalId":50800,"journal":{"name":"American Naturalist","volume":"205 1","pages":"E16-E33"},"PeriodicalIF":2.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142883390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Equilibrium Theory of Biodiversity Dynamics: A General Framework for Scaling Species Richness and Community Abundance along Environmental Gradients. 生物多样性动态平衡理论：物种丰富度和群落丰富度沿环境梯度标度的一般框架

IF 2.4 2区环境科学与生态学

American Naturalist Pub Date : 2025-01-01 Epub Date: 2024-11-12 DOI: 10.1086/733103

Jordan G Okie, David Storch

{"title":"The Equilibrium Theory of Biodiversity Dynamics: A General Framework for Scaling Species Richness and Community Abundance along Environmental Gradients.","authors":"Jordan G Okie, David Storch","doi":"10.1086/733103","DOIUrl":"https://doi.org/10.1086/733103","url":null,"abstract":"AbstractLarge-scale temporal and spatial biodiversity patterns have traditionally been explained by multitudinous particular factors and a few theories. However, these theories lack sufficient generality and do not address fundamental interrelationships and coupled dynamics among resource availability, community abundance, and species richness. We propose the equilibrium theory of biodiversity dynamics (ETBD) to address these linkages. According to the theory, equilibrium levels of species richness and community abundance emerge at large spatial scales because of the population size dependence of speciation and/or extinction rates, modulated by resource availability and the species abundance distribution. In contrast to other theories, ETBD includes the effect of biodiversity on community abundance and thus addresses phenomena such as niche complementarity, facilitation, and ecosystem engineering. It reveals how alternative stable states in both diversity and community abundance emerge from these nonlinear biodiversity effects. The theory predicts how the strength of these effects alters scaling relationships among species richness, (meta)community abundance, and resource availability along different environmental gradients. Using data on global-scale variation in tree species richness, we show how the general framework is useful for clarifying the role of speciation, extinction, and resource availability in driving macroecological patterns in biodiversity and community abundance, such as the latitudinal diversity gradient.","PeriodicalId":50800,"journal":{"name":"American Naturalist","volume":"205 1","pages":"20-40"},"PeriodicalIF":2.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142883540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Age-Specific Phenology and Reproductive Success Senescence Vary with Environmental Age in a Wild Bird. 野生鸟类的年龄物候和生殖成功衰老随环境年龄的变化而变化。

IF 2.4 2区环境科学与生态学

American Naturalist Pub Date : 2025-01-01 Epub Date: 2024-11-11 DOI: 10.1086/733182

Suzanne Bonamour, Luis-Miguel Chevin, Christophe de Franceschi, Anne Charmantier, Céline Teplitsky

{"title":"Age-Specific Phenology and Reproductive Success Senescence Vary with Environmental Age in a Wild Bird.","authors":"Suzanne Bonamour, Luis-Miguel Chevin, Christophe de Franceschi, Anne Charmantier, Céline Teplitsky","doi":"10.1086/733182","DOIUrl":"https://doi.org/10.1086/733182","url":null,"abstract":"AbstractSenescence is ubiquitous yet highly variable among species, populations, and individuals, for reasons that are poorly understood. It is not clear how environmental conditions affect senescence, especially in the wild. We explored the influence of environment on the degree of laying date age-specific variation and reproductive success senescence in wild blue tits. We disentangled the effects of age from those of previously encountered environmental conditions by introducing two complementary estimates of \"relative environmental age.\" These estimates quantify the cumulative past environment experienced by an individual through two population-level metrics: average breeding failure and adult mortality. Results confirmed that laying date first advanced and annual reproductive success first increased with age up until about 3 years old, when these trends were reversed, consistent with a senescent decline. Both proxies for environmental conditions influenced laying date age-specific rates, such that females experiencing a more favorable environment had faster phenological decline. Conversely, environmental age did not affect reproductive success and its senescence. This study demonstrates that past environment can shape phenological age-specific change beyond the effects of chronological age and suggests that senescence will be best understood by investigating the deterioration of performances with accumulating exposure to detrimental conditions across a variety of traits.","PeriodicalId":50800,"journal":{"name":"American Naturalist","volume":"205 1","pages":"76-89"},"PeriodicalIF":2.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142883409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Natural Selection after Severe Winter Favors Larger and Duller Bluebirds. 严冬过后的自然选择有利于体型更大、更钝的蓝鸟。

IF 2.4 2区环境科学与生态学

American Naturalist Pub Date : 2024-12-01 Epub Date: 2024-10-10 DOI: 10.1086/732818

Virginie Rolland, Susan L Balenger, Jennifer L Grindstaff, Lynn Siefferman

{"title":"Natural Selection after Severe Winter Favors Larger and Duller Bluebirds.","authors":"Virginie Rolland, Susan L Balenger, Jennifer L Grindstaff, Lynn Siefferman","doi":"10.1086/732818","DOIUrl":"10.1086/732818","url":null,"abstract":"AbstractExtreme cold events, which have become more frequent, can revert the direction of long-term responses to climate change. In 2021, record snowstorms swept the United States, causing wildlife die-offs that may have been associated with rapid natural selection. Our objective was to determine whether the snowstorms caused natural selection in Eastern Bluebirds (Sialia sialis). To test which mechanism most influenced their survival, we measured the morphology and coloration of fatalities and survivors at three sites. Survival was associated with a longer tarsus and with a wider, longer, and deeper beak, in support of the starvation and thermal endurance hypotheses. Additionally, bluebirds with more-ornamented plumage were less likely to have survived, perhaps because of an early energy investment in mate and site acquisition. As bluebirds encounter increasingly warm summer conditions, the longer extremities favored during the snowstorms may continue to be favored through their thermoregulatory benefits. However, the dull plumage coloration favored by natural selection during the snowstorms may be opposed by sexual selection benefits of more-ornamented plumage. Overall, responses to extreme events are difficult to predict from responses to long-term climate change, and responses to one event, such as the 2021 snowstorms, may not predict responses to a future extreme event.","PeriodicalId":50800,"journal":{"name":"American Naturalist","volume":"204 6","pages":"561-573"},"PeriodicalIF":2.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142669850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Pollen Wars: Explosive Pollination Removes Pollen Deposited from Previously Visited Flowers. 花粉大战：爆炸式授粉会清除之前来过的花朵上沉积的花粉。

IF 2.4 2区环境科学与生态学

American Naturalist Pub Date : 2024-12-01 Epub Date: 2024-10-10 DOI: 10.1086/732797

Bruce Anderson, Ana Carolina Sabino-Oliveira, Carlos Andres Matallana-Puerto, César Augusto Arvelos, Cinthia Soares Novaes, Daniela Cristina de Cario Calaça, Isadora Schulze-Albuquerque, João Pedro Santos Pereira, Jordana Oliveira Borges, Lilian Rodrigues Ferreira de Melo, Patrick Menezes Consorte, Sara Medina-Benavides, Tamires de Oliveira Andrade, Thainã Resende Monteiro, Vanessa Gonzaga Marcelo, Victor H D Silva, Paulo Eugênio Oliveira, Vinícius Lourenço Garcia de Brito

{"title":"Pollen Wars: Explosive Pollination Removes Pollen Deposited from Previously Visited Flowers.","authors":"Bruce Anderson, Ana Carolina Sabino-Oliveira, Carlos Andres Matallana-Puerto, César Augusto Arvelos, Cinthia Soares Novaes, Daniela Cristina de Cario Calaça, Isadora Schulze-Albuquerque, João Pedro Santos Pereira, Jordana Oliveira Borges, Lilian Rodrigues Ferreira de Melo, Patrick Menezes Consorte, Sara Medina-Benavides, Tamires de Oliveira Andrade, Thainã Resende Monteiro, Vanessa Gonzaga Marcelo, Victor H D Silva, Paulo Eugênio Oliveira, Vinícius Lourenço Garcia de Brito","doi":"10.1086/732797","DOIUrl":"10.1086/732797","url":null,"abstract":"AbstractPollen grains from different plants potentially compete for ovule access because flowers produce many more pollen grains than ovules. Pollen competition could occur on pollinators, where there is finite space for pollen placement. Here, we explore the explosive pollen deposition in Hypenia macrantha (Lamiaceae, a perennial flowering plant native to South America that is frequently visited by hummingbirds) and determine whether it can improve male performance by reducing pollen loads deposited by previously visited flowers. Through the simulation of floral visits utilizing a hummingbird skull, we showed that explosive pollen deposition by untriggered flowers dislodges almost twice as many pollen grains as already-triggered flowers. In addition, pollen removal increases with the amount of deposited pollen by the floral explosion, suggesting that the precision or the explosive force of pollen deposition plays a pivotal role in this pollen removal process. These results suggest that explosive pollen placement, a mechanism that has evolved in many unrelated angiosperm clades, may confer a prepollination male competition advantage to plants.","PeriodicalId":50800,"journal":{"name":"American Naturalist","volume":"204 6","pages":"616-625"},"PeriodicalIF":2.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142669855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Revisiting Clements and Gleason: Insights from Plant Distributions on Pikes Peak, Clements's Life-Long Study Site. 重新审视克莱门茨和格里森：从克莱门茨毕生研究的地点派克峰上的植物分布中获得启示。

IF 2.4 2区环境科学与生态学

American Naturalist Pub Date : 2024-12-01 Epub Date: 2024-10-14 DOI: 10.1086/732808

Julian Resasco, Diego P Vázquez, Christy M McCain, Steven D Olson

{"title":"Revisiting Clements and Gleason: Insights from Plant Distributions on Pikes Peak, Clements's Life-Long Study Site.","authors":"Julian Resasco, Diego P Vázquez, Christy M McCain, Steven D Olson","doi":"10.1086/732808","DOIUrl":"10.1086/732808","url":null,"abstract":"AbstractHow do species' distributions respond to their environments? This question was at the heart of the Clements-Gleason controversy, ecology's most famous debate. Do species respond to the environment in concerted ways, leading to distinct and cohesive assemblages (the Clementsian paradigm), or do species respond to the environment independently (the Gleasonian paradigm)? Using plant occurrences along the elevation gradient of Pikes Peak (Colorado) as a lens through which to gain insight into Clements's perspectives on the debate, we formally test for community patterns along this gradient using a modern framework unavailable at the time of Clements and Gleason. The Pikes Peak region was Clements's study area for more than 40 years, where he established a research lab and distributed sites along the elevational gradient. His investigations of plant distributions on this mountain likely influenced his views on communities. We found mixed support for the paradigms, with neither the Gleasonian paradigm nor the Clementsian paradigm fully supported. While distributions along the gradient showed evidence of clustering of species range edges, considered to be consistent with the Clementsian paradigm, the pattern was weak, and neither range edges nor species turnover peaked at ecotone elevations, as expected under the Clementsian paradigm. Our results illuminate the Clements-Gleason debate by allowing us to probe issues that complicate conclusively testing the paradigms, such as deciding on how we quantify environmental gradients and determining the appropriate scales for community patterns and processes that might generate them. Revisiting the debate also revealed that Clements's and Gleason's views had more in common than we realize. The debate may be less neatly resolved than we assume from mythos, and it continues to have relevance to basic and applied ecology today, as its legacy has shaped our (still tenuous) notion of ecological communities and the trajectory of our field.","PeriodicalId":50800,"journal":{"name":"American Naturalist","volume":"204 6","pages":"533-545"},"PeriodicalIF":2.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142669866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Bee Phenological Distributions Predicted by Inferring Vital Rates. 通过推断生命速率预测蜜蜂的时态分布

IF 2.4 2区环境科学与生态学

American Naturalist Pub Date : 2024-12-01 Epub Date: 2024-10-08 DOI: 10.1086/732763

Michael Stemkovski, Aidan Fife, Ryan Stuart, William D Pearse

{"title":"Bee Phenological Distributions Predicted by Inferring Vital Rates.","authors":"Michael Stemkovski, Aidan Fife, Ryan Stuart, William D Pearse","doi":"10.1086/732763","DOIUrl":"10.1086/732763","url":null,"abstract":"AbstractHow bees shift the timing of their seasonal activity (phenology) to track favorable conditions influences the degree to which bee foraging and flowering plant reproduction overlap. While bee phenology is known to shift due to interannual climatic variation and experimental temperature manipulation, the underlying causes of these shifts are poorly understood. Most studies of bee phenology have been phenomenological and have only examined shifts of point estimates, such as first appearance or peak timing. Such cross-sectional measures are convenient for analysis, but foraging activity is distributed across time, and pollination interactions are better described by overlap in phenological abundance curves. Here, we make simultaneous inferences about interannual shifts in bee phenology, emergence and senescence rates, population size, and the effect of floral abundance on observed bee abundance. We do this with a model of transition rates between life stages implemented in a hierarchical Bayesian framework and parameterized with fine-scale abundance time series of the sweat bee Halictus rubicundus at the Rocky Mountain Biological Laboratory in Colorado. We find that H. rubicundus's emergence cueing was highly sensitive to the timing of snowmelt but that emergence rate, senescence rate, and population size did not differ greatly across years. The present approach can be used to glean information about vital rates from other datasets on bee and flower phenology, improving our understanding of pollination interactions.","PeriodicalId":50800,"journal":{"name":"American Naturalist","volume":"204 6","pages":"E115-E127"},"PeriodicalIF":2.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142669843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Sporadic Events Have a Greater Influence on the Dynamics of Small, Isolated Populations Than Density Dependence and Environmental Conditions. 与密度依赖性和环境条件相比，零星事件对孤立小种群动态的影响更大。

IF 2.4 2区环境科学与生态学

American Naturalist Pub Date : 2024-12-01 Epub Date: 2024-10-14 DOI: 10.1086/732876

Roxanne Turgeon, Fanie Pelletier, Steeve D Côté, Marco Festa-Bianchet, Sandra Hamel

{"title":"Sporadic Events Have a Greater Influence on the Dynamics of Small, Isolated Populations Than Density Dependence and Environmental Conditions.","authors":"Roxanne Turgeon, Fanie Pelletier, Steeve D Côté, Marco Festa-Bianchet, Sandra Hamel","doi":"10.1086/732876","DOIUrl":"10.1086/732876","url":null,"abstract":"AbstractDensity dependence is often assumed in population dynamics, but its importance in small, isolated populations has been questioned. We evaluated the relative influence of density dependence, environmental conditions, and sporadic events (disease outbreaks and specialist predators) on annual population growth rate, annual female reproduction, and annual survival of juveniles and adult females in three populations of mountain ungulates. We analyzed long-term (30-47 years) individual-based data on two bighorn sheep populations and one mountain goat population in Alberta, Canada. The effect of cougar predation episodes and pneumonia epizootics on annual population growth rate was twice as strong as that of population density. While pneumonia reduced adult female and juvenile survival and predation episodes decreased all demographic rates, high density lowered only juvenile survival. Long-term studies are pivotal for understanding the dynamics of large herbivore populations, but they are rarely duplicated. Our analysis of three mountain ungulate populations with similar life history and ecological characteristics provides evidence that infrequent sporadic events can have a greater relative influence on annual population growth than density-dependent factors in isolated populations. This result contrasts with studies of larger, well-connected populations, highlighting the importance of considering sporadic events in the management and conservation of isolated populations.","PeriodicalId":50800,"journal":{"name":"American Naturalist","volume":"204 6","pages":"574-588"},"PeriodicalIF":2.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142669894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0