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Meta-analysis is the gold standard for synthesis in ecology and evolution. Together with estimating overall effect magnitudes, meta-analyses estimate differences between effect sizes via heterogeneity statistics. It is widely hypothesized that heterogeneity will be present in ecological/evolutionary meta-analyses due to the system-specific nature of biological phenomena. Despite driving recommended best practices, the generality of heterogeneity in ecological data has never been systematically reviewed. We reviewed 700 studies, finding 325 that used formal meta-analysis, of which total heterogeneity was reported in fewer than 40%. We used second-order meta-analysis to collate heterogeneity statistics from 86 studies. Our analysis revealed that the median and mean heterogeneity, expressed as I2, are 84.67% and 91.69%, respectively. These estimates are well above 'high' heterogeneity (i.e., 75%), based on widely adopted benchmarks. We encourage reporting heterogeneity in the forms of I2 and the estimated variance components (e.g., τ2) as standard practice. These statistics provide vital insights in to the degree to which effect sizes vary, and provide the statistical support for the exploration of predictors of effect-size magnitude. Along with standard meta-regression techniques that fit moderator variables, multi-level models now allow partitioning of heterogeneity among correlated (e.g., phylogenetic) structures that exist within data. [ABSTRACT FROM AUTHOR]

Comparative evaluations of population dynamics in species with temporal and spatial variation in life-history traits are rare because they require long-term demographic time series from multiple populations. We present such an analysis using demographic data collected during the interval 1978-1996 for six populations of western terrestrial garter snakes (Thamnophis elegans) from two evolutionarily divergent ecotypes. Three replicate populations from a slow-living ecotype, found in mountain meadows of northeastern California, were characterized by individuals that develop slowly, mature late, reproduce infrequently with small reproductive effort, and live longer than individuals of three populations of a fast-living ecotype found at lakeshore locales. We constructed matrix population models for each of the populations based on 8-13 years of data per population and analyzed both deterministic dynamics based on mean annual vital rates and stochastic dynamics incorporating annual variation in vital rates. (1) Contributions of highly variable vital rates to fitness (?s) were buffered against the negative effects of stochastic variation, and this relationship was consistent with differences between the meadow (M-slow) and lakeshore (L-fast) ecotypes. (2) Annual variation in the proportion of gravid females had the greatest negative effect among all vital rates on ?s. The magnitude of variation in the proportion of gravid females and its effect on ?s was greater in M-slow than L-fast populations. (3) Variation in the proportion of gravid females, in turn, depended on annual variation in prey availability, and its effect on ?s was 4-23 times greater in M-slow than L-fast populations. In addition to differences in stochastic dynamics between ecotypes, we also found higher mean mortality rates across all age classes in the L-fast populations. Our results suggest that both deterministic and stochastic selective forces have affected the evolution of divergent life-history traits in the two ecotypes, which, in turn, affect population dynamics. M-slow populations have evolved life-history traits that buffer fitness against direct effects of variation in reproduction and that spread lifetime reproduction across a greater number of reproductive bouts. These results highlight the importance of long-term demographic and environmental monitoring and of incorporating temporal dynamics into empirical studies of life-history evolution. [ABSTRACT FROM AUTHOR]

Most evolutionary theory does not deal with populations expanding or contracting in space. Invasive species, climate change, epidemics, and the breakdown of dispersal barriers, however, all create populations in this kind of spatial disequilibrium. Importantly, spatial disequilibrium can have important ecological and evolutionary outcomes. During continuous range expansion, for example, populations on the expanding front experience novel evolutionary pressures because frontal populations are assorted by dispersal ability and have a lower density of conspecifics than do core populations. These conditions favor the evolution of traits that increase rates of dispersal and reproduction. Additionally, lowered density on the expanding front eventually frees populations on the expanding edge from specialist, coevolved enemies, permitting higher investment into traits associated with dispersal and reproduction rather than defense against pathogens. As a result, the process of range expansion drives rapid life-history evolution, and this seems to occur despite ongoing serial founder events that have complex effects on genetic diversity at the expanding front. Traits evolving on the expanding edge are smeared across the landscape as the front moves through, leaving an ephemeral signature of range expansion in the life-history traits of a species across its newly colonized range. Recent studies suggest that such nonequilibrium processes during recent population history may have contributed to many patterns usually ascribed to evolutionary forces acting in populations at spatial equilibrium. [ABSTRACT FROM AUTHOR]

Indirect ecological effects (IEEs) clearly influence species dynamics and abundance, yet relatively little is known about how they influence the evolution of species involved. While genetic variation in the species causing and responding to the IEE has obvious effects, the influence of genetic variation in intermediate species remains unexamined. Given the often counterintuitive responses of populations to IEEs this seems a significant omission. Following a community genetics approach, we used a model tetra-trophic system (parasitoid wasp, aphid, barley, and rhizobacteria) to investigate the effect of genetic interactions within the two linking species (aphids and barley) on the IEE of rhizobacteria on wasps. We show that 12.4% of the variation in wasp size, a proxy for fitness, is explained by higher-order interactions between aphid genotype (A), barley genotype (B), and presence or absence of rhizobacteria (R) (Genotype[B] × Genotype[A] × Environment[R]). Thus, the IEE of rhizobacteria on the parasitoid wasp is influenced by the specific combination of aphid and barley genotypes that mediate the interactions. In some cases changes in the genotypes of the intermediate species completely reverse the effect of rhizobacteria on wasp size. Our work demonstrates that within-species genetic variation is important in shaping IEEs in communities, an essential component of community evolutionary processes. [ABSTRACT FROM AUTHOR]

Central to the ecology and evolution of a broad range of plants is understanding why they routinely have submaximal reproduction manifested as low seed : ovule and fruit : flower ratios. We know much less about the processes responsible for low seed: ovule ratios than we do for fruit : flower ratios. Current hypotheses for low seed : ovule ratios are largely drawn from those for fruit : flower ratios, including proximate (ecological) causes of pollen limitation, resource limitation, and pollen quality, as well as the ultimate (evolutionary) hypothesis of "bet, hedging" on stochastic pollination. Yet, such mechanisms operating on fruit : flower ratios at the whole-plant level may not best explain low seed : ovule ratios at the individual-flower level. We tested each of these proximate and ultimate causes for low seed : ovule ratios using the specialized pollination mutualism between senita cacti (Pachycereus schottli) and senita moths (Upiga virescens). Seed : ovule ratios were consistently low (∼0.61). Such excess ovule production by senita likely has a strong genetic component given the significant differences among plants in ovule number and the consistency in ovule production by plants within and among flowering seasons. Excess ovule production and low seed : ovule ratios could not be explained by pollen limitation, resource limitation, pollen quality, or bet hedging. Nevertheless, phenotypic selection analyses did show significant selection gradients for increased ovule number, suggesting that other evolutionary processes may be responsible for excess ovule production and low seed : ovule ratios. In contrast, low fruit: flower ratios at the whole-plant level were explained by an apparent equilibrium between pollen and resource limitation. Thus, mechanisms responsible for low fruit : flower ratios at the whole-plant level are not necessarily in accord with those of low seed : ovule ratios at the individual-flower level. This suggests that we may need to adopt a more pluralistic approach to seed : ovule ratios and consider alternative hypotheses, including a greater array of proximate and ultimate causes. Initial results of this study suggest that floral allometry, selection on correlated floral traits, stigma clogging with pollen grains, and style clogging with pollen tubes may provide promising avenues for understanding low seed : ovule ratios. [ABSTRACT FROM AUTHOR]

Given the occurrence of mixed mating systems among plants, a general mechanism explaining the evolution and maintenance of this condition is needed. Although numerous theoretical models predict mixed mating to be evolutionarily stable, conditions favoring intermediate selfing are often stringent and have limited applicability. Here we investigated the role of vegetative herbivory, a ubiquitous biotic factor limiting plant reproduction, in the mating system expression of Impatiens capensis (Balsaminaceae), a species with an obligate mixed-mating system (individuals produce both selfing, cleistogamous, and facultatively outcrossing, chasmogamous flowers). Herbivory reduced proportional chasmogamous reproduction partially, but not entirely, through a reduction in plant size and the strength of this effect varied among replicates. Herbivory decreased geitonogamous selfing in chasmogamous flowers via several mechanisms including reduced chasmogamous flower display size and pollinator visitation rate and altered pollinator composition. Overall, herbivory caused a decrease in whole-plant outcrossing, indicating that the effects of herbivory on proportional chasmogamous reproduction, which favor selfing, outweigh the effects on chasmogamous outcrossing rate, which favor outcrossing. Not only do our findings unravel the mechanisms underlying herbivore-mediated changes in the mating system, but they also point to the role of natural enemies in contributing to the maintenance of a mixed mating system. [ABSTRACT FROM AUTHOR]

An ongoing debate in ecology revolves around how species composition and ecosystem function are related. To address the mechanistic controls of this relationship, we manipulated the composition of dissolved organic matter (DOM) fed to aquatic bacteria to determine effects on both bacterial activity and community composition. Sites along terrestrial to aquatic flow paths were chosen to simulate movement of DOM through catchments, and DOM was fed to downslope and control bacterial communities. Bacterial production was measured, and DOM chemistry and bacterial community composition (using denaturing gradient gel electrophoresis of 16S rRNA genes) were characterized following incubations. Bacterial production, dissolved organic carbon (DOC)-specific bacterial production, and DOC consumption were greatest in mesocosms fed soil water DOM; soil water DOM enhanced lake and stream bacterial production by 320–670% relative to lake and stream controls. Stream DOM added to lake bacteria depressed bacterial production relative to lake controls in the early season (-78%) but not the mid-season experiment. Addition of upslope DOM to stream and lake bacterial communities resulted in significant changes in bacterial community composition relative to controls. In four of five DOM treatments, the bacterial community composition converged to the DOM source community regardless of the initial inoculum. These results demonstrate that shifts in the supply of natural DOM were followed by changes in both bacterial production and community composition, suggesting that changes in function are likely predicated on at least an initial change in the community composition. The results indicate that variation in DOM composition of soil and surface waters influences bacterial community dynamics and controls rates of carbon processing in set patterns across the landscape. [ABSTRACT FROM AUTHOR]

Density-dependent models that partition neighbors into conspecifics and heterospecifics ignore the great variation in effect of heterospecifics on focal plants. Both evolutionary theory and empirical results suggest that the negative effect of other plants on a focal plant should be higher for closely related neighbors than for less related neighbors. Using community-wide seedling mortality data from a forest where density dependence has previously been found, we searched for significant phylogenetic neighborhood effects (the 'phylodiversity' neighborhood) on seedling (<50 cm tall) survival at various spatial scales. Logistic regression models were used, with 19-mo survival of individual seedlings as the response. We found a significant positive effect of nearest taxon phylodiversity on seedling survival at the 36-m2 scale and the 4-m2 scale, indicating that seedling survival is enhanced by being in a neighborhood where heterospecifics are not closely related. At all scales there was a strong negative effect of conspecific seedling density on focal survival, and at small scales there was also an effect of heterospecific density, indicating generalized competition. We place these results (for seedling dynamics over a relatively short period of time) in the context of changes in phylodiversity between different size classes of plants in the same forest, which integrate the effects of dynamics of all size classes over long time periods. At the 36-m2 scale, there was an increase in nearest taxon phylodiversity (i.e., a decrease in phylogenetic clustering) from the seedlings (<50 cm tall) to the poles (1-5 cm diameter), consistent with the positive effect of local phylodiversity on seedling survival. In contrast, there was a marked decrease in average phylodiversity from seedlings to saplings at the same scale. The trees in the 1600 m2 surrounding the seedling plots had much lower phylodiversity than either the seedlings or saplings. Taken together, these results suggest that (1) over short time and spatial scales, local seedling phylodiversity has a positive effect on seedling survival, possibly via interaction with pathogens (which we discuss in detail), but (2) over longer time periods and larger spatial scales the effect of abiotic-related mortality results in habitat filtering for phylogenetically conserved traits. [ABSTRACT FROM AUTHOR]

The metacommunity framework predicts that local coexistence depends on the outcome of local species interactions and regional migration. In analogous fashion, spatial structure among populations can shape species interactions through evolutionary mechanisms. Yet, most metacommunity theories assume that populations do not evolve. Here, we evaluate how evolution shapes local species coexistence and exclusion within the multiscale and multispecies context embodied by the metacommunity framework. In general, coexistence in joint ecological-evolutionary models requires low to intermediate dispersal rates that can promote maintenance of both regional species and genetic diversity. These conditions support a set of key mechanisms that modify patterns of species coexistence including local adaptation, gene storage effects, genetic rescue effects, spatial genetic subsidies, and metacommunity evolution. Multispecies extensions indicate that correlated selection can further alter the outcome of interspecific interactions depending on the magnitude and direction of correlations and shape of fitness trade-offs. We suggest that an evolving metacommunity perspective has the potential to generate novel predictions about community structure and function by incorporating the genetic and species diversity that characterize natural communities. In adopting such a perspective, we seek to facilitate understanding about the interactions between evolutionary and metacommunity dynamics. [ABSTRACT FROM AUTHOR]

Periodical cicadas present numerous puzzles for biologists. First, their period is fixed, with individuals emerging as adults precisely after either 13 or 17 years (depending on species). Second, even when there are multiple species of either 13- or 17-year cicadas at the same location, only one or rarely two broods (cohorts) co-occur, so that periodical cicada adults appear episodically. Third, the 13- or 17-year periods of cicadas suggest there is something important about prime numbers. Finally, single broods can dominate large areas, with geographical boundaries of broods remaining generally stable through time. While previous mathematical models have been used to investigate some of these puzzles individually, here we investigate them all simultaneously. Unlike previous models, we take an explicitly evolutionary approach. Although not enough information is known about periodical cicadas to draw firm conclusions, the theoretical arguments favor a combination of predator satiation and nymph competition as being key to the evolution of strictly fixed periods and occurrence of only one brood at most geographical locations. Despite ecological mechanisms that can select for strictly fixed periods, there seem to be no plausible ecological mechanisms that select for periods being prime numbers. This suggests that the explanation for prime-numbered periods, rather than just fixed periods, may reside in physiological or genetic mechanisms or constraints. [ABSTRACT FROM AUTHOR]

Examines the effect of evolutionary history on local-scale plant diversity patterns. Relationship between richness and hydrogen-ion concentration (pH); Variation in soil pH; Effect of physiological tolerance on the relationship between richness and pH.

Examines the evolutionary significance of awn length variation in the clonal grass Hyparrhenia diplandra in a fire-prone savanna. Relation between seedling survival and awn length variability in a fire-prone habitat; Role of fire intensity; Flowering phenology and awn length variation.

Summarizes existing evidence on Uroleucon ambrosiae aphids host-use patterns in the field and investigates mechanistic and evolutionary explanations for these ecological patterns. Presentation of novel observational data on aphid host-use behaviors; Evaluation of the relative acceptability of the four asteraceous test plant species; Speculation on the ecological factors driving host range evolution in U. ambrosiae.

Examines causes of different life-history strategies of long-lived organisms. Evaluation of the natural selection of red-eared slider turtle; Role of the body size of hatchling turtles in natural selection; Differential mortality as explanation for size-dependent recapture probabilities; Pattern of survivorship from size-dependent predation.

Provides information on a study examining the performance of Castilleja wightii (Schrophulariaceae), a generalist root parasite, which is affected by the availability of different combinations of host species. Methodology used to conduct the study; Description of the study site; Advantages of mixed diets; Findings of the study.

Examines the theory of the evolution of mutualism, while focusing on the economic theory of relative advantage. Investigation of conditions under which species ought to specialize and trade in biological markets; Reference to game theory models using the Prisoner's Dilemma; Information on reviews and books on mutualism.

Population dynamics models have long assumed that populations are composed of a restricted number of groups, where individuals in each group have identical demographic rates and where all groups are similarly affected by density‐dependent and ‐independent effects. However, individuals usually vary tremendously in performance and in their sensitivity to environmental conditions or resource limitation, such that individual contributions to population growth will be highly variable. Recent efforts to integrate individual processes in population models open up new opportunities for the study of eco‐evolutionary processes, such as the density‐dependent influence of environmental conditions on the evolution of morphological, behavioral, and life‐history traits. We review recent advances that demonstrate how including individual mechanisms in models of population dynamics contributes to a better understanding of the drivers of population dynamics within the framework of integrated population models (IPMs). IPMs allow for the integration in a single inferential framework of different data types as well as variable population structure including sex, social group, or territory, all of which can be formulated to include individual‐level processes. Through a series of examples, we first show how IPMs can be beneficial for getting more accurate estimates of demographic traits than classic matrix population models by including basic population structure and their influence on population dynamics. Second, the integration of individual‐ and population‐level data allows estimating density‐dependent effects along with their inherent uncertainty by directly using the population structure and size to feedback on demography. Third, we show how IPMs can be used to study the influence of the dynamics of continuous individual traits and individual quality on population dynamics. We conclude by discussing the benefits and limitations of IPMs for integrating data at different spatial, temporal, and organismal levels to build more mechanistic models of population dynamics. [ABSTRACT FROM AUTHOR]

Not all herbivory is detrimental to plants. In some cases, plants can compensate for herbivory, maintain growth and fitness following damage, or even overcompensate for herbivory and perform better than if left undamaged. Examples of overcompensation to vertebrate herbivory are well known, but here we review the literature for examples of reproductive overcompensation (i.e., increased production of traits associated with fitness) and increased vegetative growth (i.e., vegetative overcompensation) following insect herbivory. We used a meta‐analysis to explore the effects of plant growth form, evolutionary history, herbivore feeding guild, and other plant and insect traits on the expression of reproductive and vegetative overcompensation by plants. Our literature search revealed 86 studies documenting examples of overcompensation for insect herbivory by 67 plant species representing 26 families. These plants included monocots and dicots, annuals and perennials, and woody and herbaceous plants. We also found that varied insect herbivores induce overcompensation, including 75 insect species in six orders representing 27 families and myriad feeding guilds. In our meta‐analysis, we calculated 53 effect sizes from 21 publications documenting reproductive overcompensation and 89 effect sizes from 40 publications documenting vegetative overcompensation. Variation in reproductive overcompensation was seen among plant growth forms, functional groups, cultivation, herbivore feeding sites, and plant and herbivore families. Variation in vegetative overcompensation was seen among plant families, herbivore families, and latitudinal gradients. We suggest overcompensation for insect herbivory may be far more prevalent than previously thought. Additional research focusing on the mechanisms, patterns, and ecological and evolutionary consequences of overcompensation for insect herbivory is likely to provide exciting new insights into this poorly understood and largely overlooked outcome of plant–insect interactions. [ABSTRACT FROM AUTHOR]

The article presents a list of books related to evolution. The article includes "Biology of gila monsters and beaded lizards," by Daniel D. Beck, "The sustainability revolution: portrait of a paradigm shift," by Andres R. Edwards, "Living with coyotes: managing predators humanely using food aversion conditioning," by Stuart R. Ellins, "Imperial gullies: soil erosion and conservation in Lesotho," by Katee B. Showers," and "Evolutionary game theory, natural selection, and Darwinian dynamics," by Thomas L. Vincent and Joel S. Brown.