scholarly journals Stochasticity-induced stabilization in ecology and evolution

2019 ◽  
Author(s):  
Antony Dean ◽  
Nadav M. Shnerb
Keyword(s):  
Population Genetics ◽  
Species Richness ◽  
Diffusion Approximation ◽  
Generation Time ◽  
Overlapping Generations ◽  
Storage Effect ◽  
Asymmetric Competition ◽  
Bet Hedging ◽  
Qualitative And Quantitative ◽  
Hedging Strategies

AbstractThe ability of random environmental variation to stabilize competitor coexistence was pointed out long ago and, in recent years, has received considerable attention. Here we suggest a novel and generic synthesis of stochasticity-induced stabilization (SIS) phenomena. The storage effect in the lottery model, together with other well-known examples drawn from population genetics, microbiology and ecology, are placed together, reviewed, and explained within a clear, coherent and transparent theoretical framework. Implementing the diffusion approximation we show that in all these systems (including discrete and continuous dynamics, with overlapping and non-overlapping generations) the ratio between the expected growth and its variance governs both qualitative and quantitative features of persistence and invasibility. We further clarify the relationships between bet-hedging strategies, generation time and SIS, study the dynamics of extinction when SIS fails and the explain effects of species richness and asymmetric competition on the stabilizing mechanism.

scholarly journals A continuum of biological adaptations to environmental fluctuation

2019 ◽  
Vol 286 (1912) ◽  
pp. 20191623 ◽  
Author(s):  
Ming Liu ◽  
Dustin R. Rubenstein ◽  
Wei-Chung Liu ◽  
Sheng-Feng Shen
Keyword(s):  
Overlapping Generations ◽  
Bet Hedging ◽  
Environmental Fluctuation ◽  
Infinite Population ◽  
Biological Adaptation ◽  
Hedging Strategies ◽  
Wide Range ◽  
Population Sizes ◽  
Environmental Unpredictability ◽  
Per Capita

Bet-hedging—a strategy that reduces fitness variance at the expense of lower mean fitness among different generations—is thought to evolve as a biological adaptation to environmental unpredictability. Despite widespread use of the bet-hedging concept, most theoretical treatments have largely made unrealistic demographic assumptions, such as non-overlapping generations and fixed or infinite population sizes. Here, we extend the concept to consider overlapping generations by defining bet-hedging as a strategy with lower variance and mean per capita growth rate across different environments. We also define an opposing strategy—the rising-tide—that has higher mean but also higher variance in per capita growth. These alternative strategies lie along a continuum of biological adaptions to environmental fluctuation. Using stochastic Lotka–Volterra models to explore the evolution of the rising-tide versus bet-hedging strategies, we show that both the mean environmental conditions and the temporal scales of their fluctuations, as well as whether population dynamics are discrete or continuous, are crucial in shaping the type of strategy that evolves in fluctuating environments. Our model demonstrates that there are likely to be a wide range of ways that organisms with overlapping generations respond to environmental unpredictability beyond the classic bet-hedging concept.

Evaluating agricultural bet-hedging strategies in the Kona Field System: New high-precision230Th/U and14C dates and plant microfossil data from Kealakekua, Hawai‘i Island

2016 ◽  
Vol 52 (1) ◽  
pp. 70-80 ◽  
Author(s):  
MARK D. McCOY ◽  
MARA A. MULROONEY ◽  
MARK HORROCKS ◽  
HAI CHENG ◽  
THEGN N. LADEFOGED
Keyword(s):  
Bet Hedging ◽  
Field System ◽  
Hedging Strategies ◽  
Plant Microfossil

scholarly journals THE FIRST DATA ON THE MEIOBENTHOS OF LAKE NERO

2020 ◽  
pp. 61-72
Author(s):  
V. Gusakov
Keyword(s):  
Species Richness ◽  
Aquatic Organisms ◽  
Quantitative Structure ◽  
Community Members ◽  
Volga River ◽  
Volga River Basin ◽  
Qualitative And Quantitative ◽  
First Results ◽  
High Species Richness ◽  
First Time

The paper provides the first results of a study of the qualitative and quantitative structure of the community of bottom meiofauna (meiobenthos) in shallow, hypereutrophic Lake Nero (Volga River basin, Yaroslavl region, Russia). In the samples, collected in early September 2017, 106 representatives from 16 systematic groups of aquatic organisms were found. About half of them had not been previously recorded in the lake's fauna. The species composition of Gastrotricha, Nematoda, Tardigrada, Acari, Harpacticoida, and Ostracoda was analyzed in the water body for the first time. It is established that at the end of the vegetation season, the lake's meiobenthos characterizes by relatively high species richness, diversity, and quantitative parameters. The circle of the main (dominant) community members in the studied period was outlined.

scholarly journals Seasonality and competition select for variable germination behavior in perennials

2022 ◽  
Author(s):  
Hanna ten Brink ◽  
Thomas Ray Haaland ◽  
Oystein Hjorthol Opedal
Keyword(s):  
Simulation Models ◽  
Population Variation ◽  
Priority Effects ◽  
Bet Hedging ◽  
Environmental Predictability ◽  
Hedging Strategies ◽  
Unpredictable Environments ◽  
Evolutionary Simulation ◽  
Negative Frequency Dependent Selection ◽  
Germination Timing

The common occurrence of within-population variation in germination behavior and associated traits such as seed size has long fascinated evolutionary ecologists. In annuals, unpredictable environments are known to select for bet-hedging strategies causing variation in dormancy duration and germination strategies. Variation in germination timing and associated traits is also commonly observed in perennials, and often tracks gradients of environmental predictability. Although bet-hedging is thought to occur less frequently in long-lived organisms, these observations suggest a role of bet-hedging strategies in perennials occupying unpredictable environments. We use complementary numerical and evolutionary simulation models of within- and among-individual variation in germination behavior in seasonal environments to show how bet-hedging interacts with density dependence, life-history traits, and priority effects due to competitive differences among germination strategies. We reveal substantial scope for bet-hedging to produce variation in germination behavior in long-lived plants, when "false starts" to the growing season results in either competitive advantages or increased mortality risk for alternative germination strategies. Additionally, we find that two distinct germination strategies can evolve and coexist through negative frequency-dependent selection. These models extend insights from bet-hedging theory to perennials and explore how competitive communities may be affected by ongoing changes in climate and seasonality patterns.

scholarly journals Interplay of population genetics and dynamics in the genetic control of mosquitoes

2014 ◽  
Vol 11 (93) ◽  
pp. 20131071 ◽  
Author(s):  
Nina Alphey ◽  
Michael B. Bonsall
Keyword(s):  
Population Genetics ◽  
Overlapping Generations ◽  
Large Scale ◽  
Genetic Model ◽  
Homing Endonuclease ◽  
Wild Type ◽  
Larval Competition ◽  
Selfish Genetic Elements ◽  
Fitness Effects ◽  
Ecological Aspects

Some proposed genetics-based vector control methods aim to suppress or eliminate a mosquito population in a similar manner to the sterile insect technique. One approach under development in Anopheles mosquitoes uses homing endonuclease genes (HEGs)—selfish genetic elements (inherited at greater than Mendelian rate) that can spread rapidly through a population even if they reduce fitness. HEGs have potential to drive introduced traits through a population without large-scale sustained releases. The population genetics of HEG-based systems has been established using discrete-time mathematical models. However, several ecologically important aspects remain unexplored. We formulate a new continuous-time (overlapping generations) combined population dynamic and genetic model and apply it to a HEG that targets and knocks out a gene that is important for survival. We explore the effects of density dependence ranging from undercompensating to overcompensating larval competition, occurring before or after HEG fitness effects, and consider differences in competitive effect between genotypes (wild-type, heterozygotes and HEG homozygotes). We show that population outcomes—elimination, suppression or loss of the HEG—depend crucially on the interaction between these ecological aspects and genetics, and explain how the HEG fitness properties, the homing rate (drive) and the insect's life-history parameters influence those outcomes.

scholarly journals Ecological niche and bet-hedging strategies for Triodia (R.Br.) seed germination

2017 ◽  
Vol 121 (2) ◽  
pp. 367-375 ◽  
Author(s):  
Wolfgang Lewandrowski ◽  
Todd E Erickson ◽  
Emma L Dalziell ◽  
Jason C Stevens
Keyword(s):  
Seed Germination ◽  
Ecological Niche ◽  
Bet Hedging ◽  
Hedging Strategies

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.

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