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Plant dispersal mechanisms rely on anatomical and morphological adaptations for the use of physical or biological dispersal vectors. Recently, studies of interactions between the dispersal unit and physical environment have uncovered fluid dynamic mechanisms of seed flight, protective measures against fire, and release mechanisms of explosive dispersers. Although environmental conditions generally dictate dispersal distances, plants are not purely passive players in these processes. Evidence suggests that some plants may enact informed dispersal, where dispersal-related traits are modified according to the environment. This can occur via developmental regulation, but also on shorter timescales via structural remodelling in relation to water availability and temperature. Linking interactions between dispersal mechanisms and environmental conditions will be essential to fully understand population dynamics and distributions.

Dormancy is a bet‐hedging strategy that allows organisms to persist through conditions that are suboptimal for growth and reproduction by entering a reversible state of reduced metabolic activity. Dormancy allows a population to maintain a reservoir of genetic and phenotypic diversity (i.e., a seed bank) that can contribute to the long‐term survival of a population. This strategy can be potentially adaptive and has long been of interest to ecologists and evolutionary biologists. However, comparatively little is known about how dormancy influences the fundamental evolutionary forces of genetic drift, mutation, selection, recombination, and gene flow. Here, we investigate how seed banks affect the processes underpinning evolution by reviewing existing theory, implementing novel simulations, and determining how and when dormancy can influence evolution as a population genetic process. We extend our analysis to examine how seed banks can alter macroevolutionary processes, including rates of speciation and extinction. Through the lens of population genetic theory, we can understand the extent that seed banks influence the evolutionary dynamics of microorganisms as well as other taxa.

Epigenetic processes manage gene expression and products in a real-time manner, allowing a single genome to display different phenotypes. In this paper, we discussed the relevance of assessing the different sources of epigenetic variation in natural populations. For a given genotype, the epigenetic variation could be environmentally induced or occur randomly. Strategies developed by organisms to face environmental fluctuations such as phenotypic plasticity and diversified bet-hedging rely, respectively, on these different sources. Random variation can also represent a proxy of developmental stability and can be used to assess how organisms deal with stressful environmental conditions. We then proposed the microbiome as an extension of the epigenotype of the host to assess the factors determining the establishment of the community of microorganisms. Finally, we discussed these perspectives in the applied context of conservation.

Bet-hedging is an ecological risk-aversion strategy in which a population does not commit all its effort toward a single reproductive event or specific environmental condition, and instead spreads the risk to include multiple reproductive events or conditions. For aquatic invertebrates in dry wetlands, this often takes the form of some propagules hatching in the first available flood, while remaining propagules hatch in subsequent floods (the “hedge”); this better ensures that a subset of propagules will hatch in a flood of sufficient duration to successfully complete development. Harsh environmental conditions are believed to promote an increased reliance on bet-hedging. Bet-hedging studies have typically been restricted to single sites or single populations. Community-level assessments may provide more robust support for the range of hatching strategies that exist in nature. Here, we tested whether freshwater zooplankton assemblages inhabiting ephemeral and unpredictable wetlands of a semiarid zone of tropical Brazil employ hatching strategies suggestive of bet-hedging; few efforts have addressed bet-hedging in the tropics where the unique conditions may influence the strategy. We collected dry sediments from six ephemeral wetlands, and flooded them across a sequence of three hydrations under similar laboratory conditions to assess whether hatching patterns conform to some of the predictions of the bet-hedging theory. We found that taxa showing hatching patterns akin to bet-hedging associated with delayed hatching numerically dominated the assemblages that emerged from dry sediments, although there was large heterogeneity in the hatching rate among sites and across taxa. While some populations distributed their hatching across all three floods and committed most of their hatching fraction to the first hydration, others committed as much or more effort to the second hydration (the “hedge”) or the third hydration (another substantial “hedge”). Thus, in the harsh study wetlands, hatching patterns akin to bet-hedging associated with delayed hatching were common and occurred at multiple temporal scales. Our community assessment found that a commitment to the “hedge” was greater than the current theory would predict. Our findings have broader implications; bet-hedger taxa seem especially well equipped to tolerate stress if conditions become harsher as environments change.

• Heteromorphic diaspores (fruits and seeds) are an adaptive bet-hedging strategy to cope with spatiotemporally variable environments, particularly fluctuations in favourable temperatures and unpredictable precipitation regimes in arid climates. • We conducted comparative analyses of the biophysical and ecophysiological properties of the two distinct diaspores (mucilaginous seed (M⁺) vs indehiscent (IND) fruit) in the dimorphic annual Aethionema arabicum (Brassicaceae), linking fruit biomechanics, dispersal aerodynamics, pericarp-imposed dormancy, diaspore abscisic acid (ABA) concentration, and phenotypic plasticity of dimorphic diaspore production to its natural habitat and climate. • Two very contrasting dispersal mechanisms of the A. arabicum dimorphic diaspores were revealed. Dehiscence of large fruits leads to the release of M⁺ seed diaspores, which adhere to substrata via seed coat mucilage, thereby preventing dispersal (antitelechory). IND fruit diaspores (containing nonmucilaginous seeds) disperse by wind or water currents, promoting dispersal (telechory) over a longer range. • The pericarp properties confer enhanced dispersal ability and degree of dormancy on the IND fruit morph to support telechory, while the M⁺ seed morph supports antitelechory. Combined with the phenotypic plasticity to produce more IND fruit diaspores in colder temperatures, this constitutes a bet-hedging survival strategy to magnify the prevalence in response to selection pressures acting over hilly terrain.

The ability of random environmental variation to stabilize competitor coexistence was pointed out long ago and, in recent years, has received considerable attention. Analyses have focused on variations in the log abundances of species, with mean logarithmic growth rates when rare, 𝔼[r], used as metrics for persistence. However, invasion probabilities and the times to extinction are not single-valued functions of 𝔼[r] and, in some cases, decrease as 𝔼[r] increases. Here, we present a synthesis of stochasticity-induced stabilization (SIS) phenomena based on the ratio between the expected arithmetic growth μ and its variance g. When the diffusion approximation holds, explicit formulas for invasion probabilities and persistence times are single-valued, monotonic functions of μ/g. The storage effect in the lottery model, together with other well-known examples drawn from population genetics, microbiology, and ecology (including discrete and continuous dynamics, with overlapping and non-overlapping generations), are placed together, reviewed, and explained within this new, transparent theoretical framework. We also clarify the relationships between life-history strategies and SIS, and study the dynamics of extinction when SIS fails

Partial migration strategies, in which some individuals migrate but others do not, are widely observed in populations of migratory animals. Such patterns could arise via variation in migratory behaviors made by individual animals, via genetic variation in migratory predisposition, or simply by variation in migration opportunities mediated by environmental conditions. Here we use spatiotemporal variation in partial migration across populations of an amphidromous Hawaiian goby to test whether stream or ocean conditions favor completing its life cycle entirely within freshwater streams rather than undergoing an oceanic larval migration. Across 35 watersheds, microchemical analysis of otoliths revealed that most adult Awaous stamineus were freshwater residents (62% of n = 316 in 2009, 83% of n = 274 in 2011), but we found considerable variation among watersheds. We then tested the hypothesis that the prevalence of freshwater residency increases with the stability of stream flows and decreases with the availability of dispersal pathways arising from ocean hydrodynamics. We found that streams with low variation of daily discharge were home to a higher incidence of freshwater residents in each survey year. The magnitude of the shift in freshwater residency between survey years was positively associated with predicted interannual variability in the success of larval settlement in streams on each island based on passive drift in ocean currents. We built on these findings by developing a theoretical model of goby life history to further evaluate whether mediation of migration outcomes by stream and ocean hydrodynamics could be sufficient to explain the range of partial migration frequency observed across populations. The model illustrates that the proportion of larvae entering the ocean and differential survival of freshwater-resident versus ocean-going larvae are plausible mechanisms for range-wide shifts in migration strategies. Thus, we propose that hydrologic variation in both ocean and stream environments contributes to spatiotemporal variation in the prevalence of migration phenotypes in A. stamineus. Our empirical and theoretical results suggest that the capacity for partial migration could enhance the persistence of metapopulations of diadromous fish when confronted with variable ocean and stream conditions.

Stochastic environments shape life-history traits and can promote selection for risk-spreading strategies, such as bet-hedging. Although the strategy has often been hypothesized to exist for various species, empirical tests providing firm evidence have been rare, mainly due to the challenge in tracking fitness across generations. Here, we take a ‘proof of principle’ approach to explore whether the reproductive strategy of multiple-batch spawning constitutes a bet-hedging. We used Atlantic cod (Gadus morhua) as the study species and parameterized an eco-evolutionary model, using empirical data on size-related reproductive and survival traits. To evaluate the fitness benefits of multiple-batch spawning (within a single breeding period), the mechanistic model separately simulated multiple-batch and single-batch spawning populations under temporally varying environments. We followed the arithmetic and geometric mean fitness associated with both strategies and quantified the mean changes in fitness under several environmental stochasticity levels. We found that, by spreading the environmental risk among batches, multiple-batch spawning increases fitness under fluctuating environmental conditions. The multiple-batch spawning trait is, thus, advantageous and acts as a bet-hedging strategy when the environment is exceptionally unpredictable. Our research identifies an analytically flexible, stochastic, life-history modelling approach to explore the fitness consequences of a risk-spreading strategy and elucidates the importance of evolutionary applications to life-history diversity.

Phenological shifts have been observed in a wide range of taxa, but the fitness consequences of these shifts are largely unknown, and we often lack experimental studies to assess their population-level and evolutionary consequences. Here, we describe an experimental study to determine the fitness consequences of phenological shifts in blue orchard bee (Osmia lignaria) emergence, compare the measured seasonal fitness landscape with observed phenology in the unmanipulated population, and assess seasonal variation in key factors related to reproduction, foraging, and brood parasitism that were expected to affect the shape of the fitness landscape. By tracking individually marked females, we were able to estimate the lifetime fitness impacts of phenological advances and delays. We also measured parasitism risk, floral resource use, and nesting behavior to understand how each varies seasonally, and their combined effects on realized fitness. Survival to nesting decreased non-monotonically throughout the season, with a 20.4% decline in survival rates between the first and second cohorts. The total reproductive output per maternal bee was 14.9% higher in the second cohort compared to the first, and 161% higher in the second cohort compared to the third. Combining seasonal patterns in survival and reproductive output, experimentally advanced females showed 30.6% higher fitness than bees released at the historic peak. In contrast, the nesting phenology of unmanipulated bees showed nearly equal numbers of nesting attempts in the first two cohorts. Both increased resource availability and reduced parasitism risk favored earlier emergence. These results are consistent with a population experiencing directional selection for earlier emergence, adaptive bet-hedging, or developmental constraints. Our study offers insight into the fitness consequences of phenological shifts, the mechanisms affecting the fitness consequences of phenological shifts in a community context, and the potential for adaptive responses to climate change.