{"title":"Balancing: A solution to our distorted indices of transient dynamics","authors":"R. A. Hinrichsen","doi":"10.1002/1438-390x.12178","DOIUrl":null,"url":null,"abstract":"Because populations are at the mercy of random disturbances large and small, they rarely, if ever, converge on predicted long‐term behaviors. Therefore, when employing matrix population models, ecologists study the dynamics of populations that depart from stable distributions. Necessary for such studies are indices of transient dynamics that measure the size of short‐term population fluctuations. These indices advance our understanding of population dynamics by revealing that population growth rate in a single timestep can far exceed the stable population growth rate. Despite their value, indices of transient behavior possess two major shortcomings: they are scale dependent and easily distorted by outsized population classes. Distortion occurs whenever immature classes, due to their sheer size, carry greater weight in the calculation of population size than mature classes. Beluga sturgeon (Huso huso), for example, have an immature age class (eggs) that is several orders of magnitude larger than its mature age classes. To remove the undue influence of outsized classes, I use balancing, which rescales classes by the stable population distribution and makes the indices of transient dynamics scale invariant. I apply balancing to 1800 population projection matrices for various species across the Animal Kingdom, using reactivity and the Henrici metric of non‐normality as indices of transient dynamics. I found that balancing profoundly changes the picture of which populations have the greatest or least potential transient dynamics. Using a population projection matrix for northern pike (Esox lucius), I demonstrate how balancing influences pseudospectra contour plots that are used to infer transient dynamics.","PeriodicalId":54597,"journal":{"name":"Population Ecology","volume":null,"pages":null},"PeriodicalIF":1.1000,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Population Ecology","FirstCategoryId":"93","ListUrlMain":"https://doi.org/10.1002/1438-390x.12178","RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"ECOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Because populations are at the mercy of random disturbances large and small, they rarely, if ever, converge on predicted long‐term behaviors. Therefore, when employing matrix population models, ecologists study the dynamics of populations that depart from stable distributions. Necessary for such studies are indices of transient dynamics that measure the size of short‐term population fluctuations. These indices advance our understanding of population dynamics by revealing that population growth rate in a single timestep can far exceed the stable population growth rate. Despite their value, indices of transient behavior possess two major shortcomings: they are scale dependent and easily distorted by outsized population classes. Distortion occurs whenever immature classes, due to their sheer size, carry greater weight in the calculation of population size than mature classes. Beluga sturgeon (Huso huso), for example, have an immature age class (eggs) that is several orders of magnitude larger than its mature age classes. To remove the undue influence of outsized classes, I use balancing, which rescales classes by the stable population distribution and makes the indices of transient dynamics scale invariant. I apply balancing to 1800 population projection matrices for various species across the Animal Kingdom, using reactivity and the Henrici metric of non‐normality as indices of transient dynamics. I found that balancing profoundly changes the picture of which populations have the greatest or least potential transient dynamics. Using a population projection matrix for northern pike (Esox lucius), I demonstrate how balancing influences pseudospectra contour plots that are used to infer transient dynamics.
期刊介绍:
Population Ecology, formerly known as Researches on Population Ecology launched in Dec 1952, is the official journal of the Society of Population Ecology. Population Ecology publishes original research articles and reviews (including invited reviews) on various aspects of population ecology, from the individual to the community level. Among the specific fields included are population dynamics and distribution, evolutionary ecology, ecological genetics, theoretical models, conservation biology, agroecosystem studies, and bioresource management. Manuscripts should contain new results of empirical and/or theoretical investigations concerning facts, patterns, processes, mechanisms or concepts of population ecology; those purely descriptive in nature are not suitable for this journal. All manuscripts are reviewed anonymously by two or more referees, and the final editorial decision is made by the Chief Editor or an Associate Editor based on the referees'' evaluations.