scholarly journals Evolutionary rescue can maintain an oscillating community undergoing environmental change

2013 ◽  
Vol 3 (6) ◽  
pp. 20130036 ◽  
Author(s):  
Gregor F. Fussmann ◽  
Andrew Gonzalez
Keyword(s):  
Environmental Change ◽  
Community Dynamics ◽  
Ecological Communities ◽  
Evolutionary Response ◽  
Evolutionary Rescue ◽  
Before And After ◽  
Internal Forces ◽  
Frequency Changes ◽  
Response To Environmental Change ◽  
Physiological Acclimation

The persistence of ecological communities is challenged by widespread and rapid environmental change. In many cases, persistence may not be assured via physiological acclimation or migration and so species must adapt rapidly in situ . This process of evolutionary rescue (ER) occurs when genetic adaptation allows a population to recover from decline initiated by environmental change that would otherwise cause extirpation. Community evolutionary rescue (CER) occurs when one or more species undergo a rapid evolutionary response to environmental change, resulting in the recovery of the ancestral community. Here, we study the dynamics of CER within a three-species community coexisting by virtue of resource oscillations brought about by nonlinear interactions between two species competing for a live resource. We allowed gradual environmental change to affect the traits that determine the strength and symmetry of the interaction among species. By allowing the component species to evolve rapidly, we found that: (i) trait evolution can allow CER and ensure the community persists by preventing competitive exclusion during environmental change, (ii) CER brings about a change in the character of the oscillations (period, amplitude) governing coexistence before and after environmental change, and (iii) CER may depend on evolutionary change that occurs simultaneously with or subsequently to environmental change. We were able to show that a change in the character of community oscillations may be a signature that a community is undergoing ER. Our study extends the theory on ER to a world of nonlinear community dynamics where—despite high-frequency changes of population abundances—adaptive evolutionary trait change can be gradual and directional, and therefore contribute to community rescue. ER may happen in real, complex communities that fluctuate owing to a mix of external and internal forces. Experiments testing this theory are now required to validate our predictions.

scholarly journals Modes of response to environmental change and the elusive empirical evidence for bet hedging

2011 ◽  
Vol 278 (1712) ◽  
pp. 1601-1609 ◽  
Author(s):  
Andrew M. Simons
Keyword(s):  
Environmental Change ◽  
Empirical Evidence ◽  
Natural Environments ◽  
Bet Hedging ◽  
Fluctuating Selection ◽  
Hedging Strategies ◽  
Evolutionary Response ◽  
Human Decision ◽  
Response To Environmental Change

Uncertainty is a problem not only in human decision-making, but is a prevalent quality of natural environments and thus requires evolutionary response. Unpredictable natural selection is expected to result in the evolution of bet-hedging strategies, which are adaptations to long-term fluctuating selection. Despite a recent surge of interest in bet hedging, its study remains mired in conceptual and practical difficulties, compounded by confusion over what constitutes evidence for its existence. Here, I attempt to resolve misunderstandings about bet hedging and its relationship with other modes of response to environmental change, identify the challenges inherent to its study and assess the state of existing empirical evidence. The variety and distribution of plausible bet-hedging traits found across 16 phyla in over 100 studies suggest their ubiquity. Thus, bet hedging should be considered a specific mode of response to environmental change. However, the distribution of bet-hedging studies across evidence categories—defined according to potential strength—is heavily skewed towards weaker categories, underscoring the need for direct appraisals of the adaptive significance of putative bet-hedging traits in nature.

scholarly journals Genomic signatures of evolutionary rescue in bats surviving white-nose syndrome

2018 ◽  
Author(s):  
Sarah A. Gignoux-Wolfsohn ◽  
Malin L. Pinsky ◽  
Kathleen Kerwin ◽  
Carl Herzog ◽  
MacKenzie Hall ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Environmental Change ◽  
Rapid Evolution ◽  
Genomic Signatures ◽  
White Nose Syndrome ◽  
Multiple Loci ◽  
Evolutionary Rescue ◽  
Before And After ◽  
Soft Selection ◽  
Little Brown Bat

AbstractRapid evolution of advantageous traits following abrupt environmental change can help populations grow and avoid extinction through evolutionary rescue. Here, we provide the first genetic evidence for rapid evolution in bat populations affected by white-nose syndrome (WNS). By comparing genetic samples from before and after little brown bat populations were decimated by WNS, we identified signatures of soft selection on standing genetic variation. This selection occurred at multiple loci in genes linked to hibernation behavior rather than immune function, suggesting that differences in hibernation strategy have allowed these bats to survive infection with WNS. Through these findings, we suggest that evolutionary rescue can be a conservationrelevant process even in slowly reproducing taxa threatened with extinction.

Species in variable environments

2019 ◽  
pp. 287-306
Author(s):  
Gary G. Mittelbach ◽  
Brian J. McGill
Keyword(s):  
Environmental Change ◽  
Species Interactions ◽  
Species Coexistence ◽  
Dynamic State ◽  
Ecological Communities ◽  
Variable Environments ◽  
Degraded Ecosystems ◽  
Alternative Community ◽  
Response To Environmental Change ◽  
Alternative Community States

Species and communities may exist in a dynamic state of change in response to environmental variation and disturbance. This chapter explores the consequences of variable environments and disturbance to species interactions and community structure. In particular, it examines how disturbance can result in the succession of ecological communities, how disturbance may promote (or hinder) species coexistence, how a varying environment can promote species coexistence through a mechanism called the “storage effect”, and how communities may shift between alternative states in response to environmental change. The latter topic is particularly relevant to the management of biotic resources and the restoration of degraded ecosystems, as systems may respond to environmental change abruptly at a “tipping point”, leading to alternative community states that can be difficult to reverse.

scholarly journals Evolutionary rescue in randomly mating, selfing, and clonal populations

2016 ◽  
Author(s):  
Hildegard Uecker
Keyword(s):  
Environmental Change ◽  
Random Mating ◽  
Diploid Species ◽  
Evolutionary Rescue ◽  
Before And After ◽  
Establishment Probability ◽  
Population Survival ◽  
Set Up ◽  
Mutant Homozygote ◽  
Allele Model

AbstractSevere environmental change can drive a population extinct unless the population adapts in time to the new conditions (“evolutionary rescue”). How does bi-parental sexual reproduction influence the chances of population persistence compared to clonal reproduction or selfing? In this paper, we set up a one-locus two-allele model for adaptation in diploid species, where rescue is contingent on the establishment of the mutant homozygote. Reproduction can occur by random mating, selfing, or clonally. Random mating generates and destroys the rescue mutant; selfing is efficient at generating it but at the same time depletes the heterozygote, which can lead to a low mutant frequency in the standing genetic variation and also affects the establishment probability of the mutation. Due to these antagonistic effects, we find a non-trivial dependence of population survival on the rate of sex/selfing, which is strongly affected by the dominance coefficient of the mutation before and after the environmental change. Importantly, since mating with the wildtype breaks the mutant homozygote up, a slow decay of the wildtype population size can impede rescue in randomly mating populations.

scholarly journals Eco-evolutionary community turnover following environmental change

2018 ◽  
Author(s):  
Jesse R. Lasky
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Environmental Change ◽  
Community Dynamics ◽  
Environmental Gradients ◽  
Interspecific Variation ◽  
Community Response ◽  
High Gene Flow ◽  
High Gene ◽  
Response To Environmental Change

AbstractCo-occurring species often differ in intraspecific genetic diversity, which in turn can affect adaptation in response to environmental change. Specifically, the simultaneous evolutionary responses of co-occurring species to temporal environmental change may influence community dynamics. Local adaptation along environmental gradients combined with gene flow can promote genetic diversity of traits under selection within populations. Here I build off existing quantitative genetic theory to study community dynamics of locally adapted species in response to temporal environmental change. I show that species with greater gene flow have lower equilibrium population size due to maladaptive immigrant genotypes (migration load). However, following abrupt environmental change that leaves all species initially maladapted, high gene flow species adapt faster due to greater standing genetic diversity. As a result, communities may undergo a transient reversal in relative abundance, sometimes only after substantial lag periods. If constant temporal environmental change is applied, the community exhibits a shift toward stable dominance by species with intermediate gene flow. High gene flow species can sometimes increase abundance under environmental change if environmental change supresses superior competitor but lower gene flow species. The community dynamics observed here parallel the purely ecological successional dynamics following disturbances and are analogous to the transient benefit of hypermutator alleles under changing environments. My results demonstrate how interspecific variation in life history can have far-reaching impacts on eco-evolutionary community response to environmental change.

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