{"title":"Strengthening of negative density dependence mediates population decline at high temperatures","authors":"Lillie Stockseth, Zoey Neale, Volker H. W. Rudolf","doi":"10.1002/ecy.70030","DOIUrl":null,"url":null,"abstract":"<p>While temperature is well known to affect many life history traits of ectothermic organisms, any attempt to scale up these individual-level processes to population-level consequences must assume a relationship between temperature and the strength of per capita density dependence. Yet, theory has made contrasting predictions about this relationship, and we still need clear experimental tests to determine which relationship is realized in natural systems, especially in heterotrophs. Here, we experimentally isolated and quantified the thermal response of density dependence from the population dynamics of the herbivore <i>Daphnia pulex</i>. We show that the strength of negative density dependence increased linearly with temperature, doubling every 7°C, while the intrinsic growth rate of increase showed a humped shape relationship. This difference caused a humped-shaped relationship of carrying capacity with temperature, with a dramatic 50% decline at the highest temperature. The results provide a sorely needed test of theory and highlight the importance of accounting for thermal responses of indirect effects that only emerge at the population level when forecasting the effects of global warming. While warming temperatures may benefit the individual (via increased growth and reproduction), our results reveal that warming still can be a detriment to the population by strengthening density-dependent processes.</p>","PeriodicalId":11484,"journal":{"name":"Ecology","volume":"106 3","pages":""},"PeriodicalIF":4.4000,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ecy.70030","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Ecology","FirstCategoryId":"93","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/ecy.70030","RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ECOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
While temperature is well known to affect many life history traits of ectothermic organisms, any attempt to scale up these individual-level processes to population-level consequences must assume a relationship between temperature and the strength of per capita density dependence. Yet, theory has made contrasting predictions about this relationship, and we still need clear experimental tests to determine which relationship is realized in natural systems, especially in heterotrophs. Here, we experimentally isolated and quantified the thermal response of density dependence from the population dynamics of the herbivore Daphnia pulex. We show that the strength of negative density dependence increased linearly with temperature, doubling every 7°C, while the intrinsic growth rate of increase showed a humped shape relationship. This difference caused a humped-shaped relationship of carrying capacity with temperature, with a dramatic 50% decline at the highest temperature. The results provide a sorely needed test of theory and highlight the importance of accounting for thermal responses of indirect effects that only emerge at the population level when forecasting the effects of global warming. While warming temperatures may benefit the individual (via increased growth and reproduction), our results reveal that warming still can be a detriment to the population by strengthening density-dependent processes.
期刊介绍:
Ecology publishes articles that report on the basic elements of ecological research. Emphasis is placed on concise, clear articles documenting important ecological phenomena. The journal publishes a broad array of research that includes a rapidly expanding envelope of subject matter, techniques, approaches, and concepts: paleoecology through present-day phenomena; evolutionary, population, physiological, community, and ecosystem ecology, as well as biogeochemistry; inclusive of descriptive, comparative, experimental, mathematical, statistical, and interdisciplinary approaches.