Fitness differences override variation‐dependent coexistence mechanisms in California grasslands DOI
Andrew J. Muehleisen, C. T. White, Lauren G. Shoemaker

и другие.

Journal of Ecology, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 22, 2024

Abstract While most studies of species coexistence focus on the mechanisms that maintain coexistence, it is equally important to understand structure failed coexistence. For example, California annual grasslands are heavily invaded ecosystems, where non‐native annuals have largely dominated and replaced native communities. These systems also highly variable, with a high degree rainfall seasonality interannual variability—a quality implicated in functionally distinct species. Yet, despite apparent strength this variation, between system has faltered. To test how variation‐dependent modulate we implemented competition experiment two previously common forbs three now‐dominant grasses spanning conservative‐acquisitive range traits. We grew individuals from each under varying densities all other as competitors, either wetter or drier early season treatments. Using subsequent seed production, parameterized models, assessed potential for among pairs quantified relative influence mechanisms. As expected, found little Competition was by grass Avena fatua , while were unable invade grasses. Mutual competitive exclusion across almost often contingent rainfall, suggesting rainfall‐mediated priority effects. Among mechanisms, temporal storage effect had moderate stabilizing four five when averaged nonlinearity destabilizing, except conservative grass, which benefited release dry conditions. Synthesis : Our findings suggest variability does mitigate fitness differences underlie widespread invasion California, but influences dynamics

Язык: Английский

Loss of Earth’s old, wise, and large animals DOI
R. Keller Kopf,

Sam C. Banks,

Lauren J. N. Brent

и другие.

Science, Год журнала: 2024, Номер 387(6729)

Опубликована: Ноя. 21, 2024

Earth’s old animals are in decline. Despite this, emerging research is revealing the vital contributions of older individuals to cultural transmission, population dynamics, and ecosystem processes services. Often largest most experienced, valued by humans make important reproduction, information acquisition trophic resistance resilience natural anthropogenic disturbance. These observations contrast with senescence-focused paradigm age that has dominated literature for more than a century yet consistent findings from behavioral ecology life history theory. In this work, we review why global loss can be particularly detrimental long-lived indeterminate growth; those increasing reproductive output age; dependent on migration, sociality, transmission survival. Longevity conservation needed protect ecological roles services provided animals.

Язык: Английский

Процитировано

5
Reexamining the storage effect: Why temporal variation in abiotic factors seems unlikely to cause coexistence DOI
Simon Maccracken Stump, David A. Vasseur

Ecological Monographs, Год журнала: 2023, Номер 93(4)

Опубликована: Июнь 3, 2023

Abstract The temporal storage effect—that species coexist by partitioning abiotic niches that vary in time—is thought to be an important explanation for how coexist. However, empirical studies measure multiple mechanisms often find the effect is weak. We believe this mismatch because of a shortcoming theoretical models used study effect: while described as having just three requirements (partitioning variation, buffered population growth, and covariance between environment density‐dependence), make four assumptions, which are mathematically subtle but biologically important. In paper, we examine those assumptions. First, assume environmental variation leads rapid impact on density‐dependence. delays density‐dependence (including caused competition cohorts) weaken effect. Second, intraspecific almost identical interspecific competition. unless resource or predator virtually absent, then variation‐independent will overshadow benefits Third, even though there vast environment, equally adapted average (i.e., zero fitness‐differences). show fitness differences particularly problematic specializing temporally rare far less effective than other types niches. Finally, stochastic extinctions can ignored, invader growth determine coexistence. effects tend reduce mean persistence times, if rates positive. These results suggest assumptions needed strict: first second assumption relaxed, it greatly stabilizing mechanism; third fourth create diversity‐destroying may undermine real‐world communities—annual plants, tropical forests, iguanid lizards—and all communities violate This suggests probably not diversity most systems.

Язык: Английский

Процитировано

8
Eco‐evolutionary maintenance of diversity in fluctuating environments DOI Creative Commons
Masato Yamamichi, Andrew D. Letten, Sebastian J. Schreiber

и другие.

Ecology Letters, Год журнала: 2023, Номер 26(S1)

Опубликована: Сен. 1, 2023

Abstract Growing evidence suggests that temporally fluctuating environments are important in maintaining variation both within and between species. To date, however, studies of genetic a population have been largely conducted by evolutionary biologists (particularly geneticists), while community ecologists concentrated more on diversity at the species level. Despite considerable conceptual overlap, commonalities differences these two alternative paradigms yet to come under close scrutiny. Here, we review theoretical empirical genetics ecology focusing ‘temporal storage effect’ synthesise theories maintenance across different levels biological organisation. Drawing Chesson's coexistence theory, explain how promote diversity. We propose further synthesis disciplines comparing models employing traditional frequency‐dependent dynamics those adopting density‐dependent dynamics. then address temporal fluctuations simultaneously via rapid evolution eco‐evolutionary Comparing synthesising ecological approaches will accelerate our understanding nature.

Язык: Английский

Процитировано

8
Fluctuation-dependent coexistence of stage-structured species DOI
Chhaya M. Werner, Lauren M. Hallett, Lauren G. Shoemaker

и другие.

The American Naturalist, Год журнала: 2024, Номер 205(3), С. 327 - 341

Опубликована: Окт. 2, 2024

AbstractModern coexistence theory is a dominant framework for understanding how environmental fluctuations promote species coexistence. However, assessing fluctuation-dependent mechanisms of in empirical systems-in which have diverse life histories and environment-competition relationships-has remained challenging many ecologists. To help empiricists theoreticians alike build intuition the role across systems environments, we explore two stage-structured histories-perennial seedbanking annuals-differ competition with nonseedbanking annual three scenarios. Our scenarios delineate partition resources within among years whether most intense during favorable or unfavorable periods. We use this work to link differences vital rates interaction strengths patterns Fluctuation-dependent can be equally important perennial an adult "storage" stage as annuals. outcomes differentiate between these strategies based on they experience stronger weaker environments. This sets applying partitioning frameworks mixed stage-structure communities, facilitating variation drives dynamics broader range systems.

Язык: Английский

Процитировано

2
It's about (taking up) space: Discreteness of individuals and the strength of spatial coexistence mechanisms DOI Open Access
Stephen P. Ellner, Robin E. Snyder, Peter B. Adler

и другие.

Ecology, Год журнала: 2024, Номер 105(11)

Опубликована: Окт. 6, 2024

Abstract One strand of modern coexistence theory (MCT) partitions invader growth rates (IGR) to quantify how different mechanisms contribute species coexistence, highlighting fluctuation‐dependent mechanisms. A general conclusion from the classical analytic MCT is that relying on temporal variation (such as storage effect) are generally less effective at promoting than spatial or spatiotemporal (primarily growth‐density covariance). However, assumes continuous population density, and IGRs calculated for infinitesimally rare invaders have infinite time find their preferred habitat regrow, without ever experiencing intraspecific competition. Here we ask if disparity between persists when individuals are, instead, discrete occupy finite amounts space. We present a simulation‐based approach quantifying in this situation, building our previous spatially non‐varying habitats. As expected, found weakened; unexpectedly, contribution IGR covariance could even become negative, opposing coexistence. also shifts which demographic parameters had largest effect strength Our substantive conclusions statements about one model, across parameter ranges subjectively considered realistic. Using methods developed here, effects individual discreteness should be explored theoretically broader range conditions, models parameterized empirical data real communities.

Язык: Английский

Процитировано

1
Asymmetric relationships and their effects on coexistence DOI

Pimsupa Jasmin Albert,

Daniel C. Reuman

Ecology Letters, Год журнала: 2023, Номер 27(1)

Опубликована: Ноя. 13, 2023

Abstract Species coexistence attracts wide interest in ecology. Modern theory (MCT) identifies mechanisms, one of which, storage effects, hinges on relationships between fluctuations environmental and competitive pressures. However, such are typically measured using covariance, which does not account for the possibility that environment competition may be more related to each other when they strong than weak, or vice versa. Recent work showed ‘asymmetric tail associations’ (ATAs) common ecological variables, important extinction risk, ecosystem stability, phenomena. We extend MCT, decomposing effects show influence ATAs. Analysis a simple model an empirical example diatoms illustrate ATA influences can comparable magnitude mechanisms ATAs make difference species exclusion. new mechanism coexistence.

Язык: Английский

Процитировано

1
Dormancy promotes coexistence in fluctuating environments DOI Creative Commons
Natalie T. Jones,

Joanna D. Bundus,

Jonathan B. Shurin

и другие.

Oikos, Год журнала: 2024, Номер unknown

Опубликована: Окт. 4, 2024

Dormancy allows organisms to survive hostile conditions and is hypothesized enable species coexist in fluctuating environments. Although determining how avoid extinction critical understanding the dynamics of natural populations, experimental work exploring if when dormancy rescues populations from remains rare. We conducted an experiment, where we grew two nematode at three temperatures. Strains Caenorhabditis elegans had mutations altering their propensity enter a dormant stage briggsae was single strain with wildtype background. used those empirical results parameterize model simulate competitive outcomes environments between species. show that upregulating pathway would otherwise go extinct, thereby increasing coexistence competing By leveraging genetic tools available system, this study provides confirmation specifically facilitates promotes diversity. This system could be more expansively explore role interactions.

Язык: Английский

Процитировано

0
Fitness differences override variation‐dependent coexistence mechanisms in California grasslands DOI
Andrew J. Muehleisen, C. T. White, Lauren G. Shoemaker

и другие.

Journal of Ecology, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 22, 2024

Abstract While most studies of species coexistence focus on the mechanisms that maintain coexistence, it is equally important to understand structure failed coexistence. For example, California annual grasslands are heavily invaded ecosystems, where non‐native annuals have largely dominated and replaced native communities. These systems also highly variable, with a high degree rainfall seasonality interannual variability—a quality implicated in functionally distinct species. Yet, despite apparent strength this variation, between system has faltered. To test how variation‐dependent modulate we implemented competition experiment two previously common forbs three now‐dominant grasses spanning conservative‐acquisitive range traits. We grew individuals from each under varying densities all other as competitors, either wetter or drier early season treatments. Using subsequent seed production, parameterized models, assessed potential for among pairs quantified relative influence mechanisms. As expected, found little Competition was by grass Avena fatua , while were unable invade grasses. Mutual competitive exclusion across almost often contingent rainfall, suggesting rainfall‐mediated priority effects. Among mechanisms, temporal storage effect had moderate stabilizing four five when averaged nonlinearity destabilizing, except conservative grass, which benefited release dry conditions. Synthesis : Our findings suggest variability does mitigate fitness differences underlie widespread invasion California, but influences dynamics

Язык: Английский

Процитировано

0