Explore the vast range of titles available.

It is not known whether evolution will usually be rapid enough to allow a species to adapt and persist in a deteriorating environment. We tracked the eco-evolutionary dynamics of metapopulations with a laboratory model system of yeast exposed to salt stress. Metapopulations experienced environmental deterioration at three different rates and their component populations were either unconnected or connected by local dispersal or by global dispersal. We found that adaptation was favored by gradual deterioration and local dispersal. After further abrupt deterioration, the frequency of evolutionary rescue depended on both the prior rate of deterioration and the rate of dispersal. Adaptation was surprisingly frequent and rapid in small peripheral populations. Thus, evolutionary dynamics affect both the persistence and the range of a species after environmental deterioration.

Habitat loss fragments metacommunities, altering the movement of species between previously connected habitat patches. The consequences of habitat loss for ecosystem functioning depend, in part, on how these changes in connectivity alter the spatial insurance effects of biodiversity. Spatial insurance is the maintenance of biodiversity and stable ecosystem functioning in changing environments that occurs when species are able to move between local habitat patches in order to track conditions to which they are adapted. Spatial insurance requires a combination of species sorting dynamics, which allow species to disperse to habitats where they are productive, and mass effect dynamics, where dispersal allows species to persist in marginal habitats where environmental conditions do not support growth. Here we use a spatially explicit metacommunity model to show that the relative contribution of species sorting and mass effects to spatial insurance changes with the rate of dispersal. We then simulate different sequences of habitat loss by removing habitat patches based on their betweenness centrality (the degree to which a patch serves as a connection between other patches in the metacommunity). We demonstrate that the sequence of habitat loss has a large, non-linear impact on diversity, ecosystem functioning and stability. Spatial insurance is lost because habitat fragmentation impedes species sorting, while promoting mass effects and dispersal limitation. We find that species sorting dynamics, and thus spatial insurance, are most robust to the removal of habitat patches with low betweenness centrality. These findings advance our understanding of how habitat connectivity facilitates the maintenance of biodiversity and ecosystem functioning, and may prove useful for the design of habitat networks.

Whether evolution will be rapid enough to rescue declining populations will depend upon population size, the supply of genetic variation, the degree of maladaptation and the historical direction of selection. We examined whether the level of environmental stress experienced by a population prior to abrupt environmental change affects the probability of evolutionary rescue (ER). Hundreds of populations of two species of yeast, Saccharomyces cerevisiae and Saccharomyces paradoxus were exposed to a range of sublethal concentrations of salt for approximately a hundred generations before transfer to a concentration of salt lethal to the ancestor (150 g l–1 NaCl). The fitness of surviving populations of both species was a quadratic function of yield: fitness was greatest for large populations that had been selected on low salt concentrations (less than 20 g l−1 NaCl) and small populations that had adapted to high salt (more than 80 g l−1 NaCl). However, differences occurred between species in the probability of ER. The frequency of ER was positively correlated with salt concentration for S. cerevisiae, but negatively correlated with salt concentration in S. paradoxus. These results not only demonstrate that past environmental conditions can determine the probability of ER after abrupt environmental change, but also suggest that there may even be differences between closely related species that are worth further exploration.

Ecological communities are constantly responding to environmental change. Theory and evidence suggest that the loss or decline of stress-intolerant species can be compensated for by the growth of other species. Compensatory dynamics are a long-term feature of community dynamics across a broad range of models, and they can have strong stabilizing effects at the community level. Coexistence theory indicates that distinct environmental responses are required for compensatory dynamics and deemphasizes competition. Compensatory dynamics have been detected under experimental conditions, but are not dominant in a metanalysis of field surveys. Recent progress has been made in quantitative methods that detect compensatory dynamics at different temporal scales. Appropriate null models are required to sharpen our understanding of compensatory dynamics in nature. An integrated theory of compensation and compensatory dynamics will improve our ability to understand when communities maintain sufficient response diversity to buffer the effects of environmental change and anthropogenic stress.

Designing connected landscapes is among the most widespread strategiesfor achieving biodiversity conservation targets. The challenge lies in simultaneously satisfying the connectivity needs of multiple species at multiple spatial scales under uncertain climate and land-use change. To evaluate the contribution of remnant habitat fragments to the connectivity of regional habitat networks, we developed a method to integrate uncertainty in climate and land-use change projections with the latest developments in network-connectivity research and spatial, multipurpose conservation prioritization. We used land-use change simulations to explore robustness of species' habitat networks to alternative development scenarios. We applied our method to 14 vertebrate focal species of periurban Montreal, Canada. Accounting for connectivity in spatial prioritization strongly modified conservation priorities and the modified priorities were robust to uncertain climate change. Setting conservation priorities based on habitat quality and connectivity maintained a large proportion of the region's connectivity, despite anticipated habitat loss due to climate and land-use change. The application of connectivity criteria alongside habitat-quality criteria for protected-area design was efficient with respect to the amount of area that needs protection and did not necessarily amplify trade-offs among conservation criteria. Our approach and results are being applied in and around Montreal and are well suited to the design of ecological networks and green infrastructure for the conservation of biodiversity and ecosystem services in other regions, in particular regions around large cities, where connectivity is critically low. El diseño de paisajes conectados está entre las estrategias más utilizadas para alcanzar los objetivos de conservación de la biodiversidad. El reto yace en satisfacer simultáneamente las necesidades de conectividad de especies múltiples a escalas espaciales múltiples bajo el clima y el cambio de uso de suelo incierto. Para evaluar la contribución de los fragmentos de hábitat rémanentes a la conectividad de las redes de hábitats regionales desarrollamos un método para integrar la incertidumbre en las proyecciones climáticas y de cambio de uso de suelo a los desarrollos más recientes en la investigación de conectividad de redes y la priorización de la conservación espacial y multipropósito. Usamos las simulaciones de cambio de uso de suelo para explorar la resistencia de las redes de hábitats de especies ante escenarios alternativos de desarrollo. Aplicamos nuestro método a 14 especies focales de vertebrados de la zona periurbana de Montreal, Canadá. Considerar a la conectividad en la priorización espacial modificó fuertemente las prioridades de conservación y las prioridades modificadas fueron resistentes al cambio climático incierto. Establecer las prioridades de conservatión con base en la calidad del hábitat y la conectividad mantuvo una gran proportión de la conectividad de la región, a pesar de la pérdida anticipada del hábitat debido al climay al cambio del uso de suelo. La aplicación de los criterios de conectividad junto con los criterios de calidad de hábitat para el diseño de áreas protegidas fue eficiente con respecto a la cantidad del área que necesita protección y no amplificó necesariamente las compensaciones entre los criterios de conservatión. Nuestra estrategia y resultados estón siendo aplicados en y alrededor de Montreal y son muy adecuados para el diseño de las redes ecológicasy la infraestructura verde para la conservatión de la biodiversidad y los servicios ambientales en otras regiones, en particular en regiones que rodean grandes ciudades y en donde la conectividad es críticamente baja.

A significant fraction of the Earth's land surface is dominated by bryophytes. Research on carbon and nitrogen budgets of tundra, boreal, and peatland ecosystems has demonstrated the important role of mosses in understanding global change. Bryophytes are also habitat to a highly diverse microbiota that plays a key role in the function of these ecosystems. Here we define the term bryosphere to emphasize the combined role of mosses and their associated organisms in the functioning of ecosystems from local to global scales. In this minireview, we emphasize the value of the bryosphere as a spatially bounded, whole ecosystem that integrates aboveground and belowground processes, and we highlight the potential of the bryosphere as a natural model system (NMS) to assist in the study of environmental change on biodiversity and ecosystem functioning. We propose a formal definition of the bryosphere, attempt to summarize the current state of knowledge of the bryosphere, and discuss how the bryosphere can be a complex yet tractable system under an NMS framework. Recent use of the bryosphere as an NMS has shown how alterations in food web structure can affect ecosystem function in a manner that, although predicted by theory, has remained largely untested by experiment. An understanding of the biodiversity, ecosystem functioning, and adaptation of the bryosphere can be advanced by manipulative experiments coupled with a blend of techniques in molecular, physiological, community, and ecosystem ecology. Although studies described herein have demonstrated the utility of the bryosphere NMS for addressing ecological theory, the bryosphere is an underutilized system with exceptional promise.

Food webs are highly complex ecological networks, dynamic in both space and time. Metacommunity models are now at the core of unified theories of biodiversity, but to date they have not addressed food web complexity. Here we show that metacommunity theory can explain the emergence of species-rich food webs with complex network topologies. Our analysis shows that network branching in the food web is maximized at intermediate colonization rates and limited dispersal scales, which also leads to concomitant peaks in species diversity. Increased food web complexity and species diversity are made possible by the structural role played by network branches that are supported by omnivore and generalist feeding links. Thus, in contrast to traditional food web theory, which emphasizes the destabilizing effect of omnivory feeding in closed systems, metacommunity theory predicts that these feeding links, which are commonly observed in empirical food webs, play a critical structural role as food webs assemble in space. As this mechanism functions at the metacommunity level, evidence for its operation in nature will be obtained through multiscale surveys of food web structure. Finally, we apply our theory to reveal the effects of habitat destruction on network complexity and metacommunity diversity.

The relationship between biological diversity and ecological stability has fascinated ecologists for decades. Determining the generality of this relationship, and discovering the mechanisms that underlie it, are vitally important for ecosystem management. Here, we investigate how species richness affects the temporal stability of biomass production by reanalyzing 27 recent biodiversity experiments conducted with primary producers. We find that, in grasslands, increasing species richness stabilizes whole-community biomass but destabilizes the dynamics of constituent populations. Community biomass is stabilized because species richness impacts mean biomass more strongly than its variance. In algal communities, species richness has a minimal effect on community stability because richness affects the mean and variance of biomass nearly equally. Using a new measure of synchrony among species, we find that for both grasslands and algae, temporal correlations in species biomass are lower when species are grown together in polyculture than when grown alone in monoculture. These results suggest that interspecific interactions tend to stabilize community biomass in diverse communities. Contrary to prevailing theory, we found no evidence that species’ responses to environmental variation in monoculture predicted the strength of diversity’s stabilizing effect. Together, these results deepen our understanding of when and why increasing species richness stabilizes community biomass.

ContextAn important output of connectivity science is the identification of priority areas for the conservation of landscape connectivity. However, current connectivity conservation planning methods rarely take into account risks associated with future land use and climate change, and seldom incorporate stakeholder perceptions of connectivity priorities.ObjectivesWe modeled future connectivity change for five umbrella vertebrate species in a fragmented landscape, the Montérégie region in Québec, Canada. We aimed to show how connectivity, land use change, and climate change models can be integrated with stakeholder information to derive simple connectivity assessments and conservation scenarios.MethodsWe projected change in ecological connectivity along with land use and climate change, for five vertebrate species whose needs are representative of the habitat and movement needs of many other vertebrates in our study region. We organized a participatory workshop with local stakeholders, utilizing methods of consensus building to identify priority areas for connectivity. We used the results to generate simple connectivity conservation scenarios.ResultsLand use change strongly impacted connectivity negatively for all species. The effects were worsened by climate change the more our species relied on climate-sensitive forest habitats, suggesting that interactions between climate and land use change can matter even at sub-regional scales. Integrating stakeholders’ priorities into connectivity modeling allowed for the definition of useful scenarios.ConclusionsOur results highlight the relevance of an iterative, multi-stakeholder approach to the definition of scenarios for connectivity conservation priorities. Integrated models can support the scenario-making process for fragmented landscapes, where deriving realistic and relevant alternative scenarios is challenging.

Variability in the environment defines the structure and dynamics of all living systems, from organisms to ecosystems. Species have evolved traits and strategies that allow them to detect, exploit and predict the changing environment. These traits allow organisms to maintain steady internal conditions required for physiological functioning through feedback mechanisms that allow internal conditions to remain at or near a set-point despite a fluctuating environment. In addition to feedback, many organisms have evolved feedforward processes, which allow them to adjust in anticipation of an expected future state of the environment. Here we provide a framework describing how feedback and feedforward mechanisms operating within organisms can generate effects across scales of organization, and how they allow living systems to persist in fluctuating environments. Daily, seasonal and multi-year cycles provide cues that organisms use to anticipate changes in physiologically relevant environmental conditions. Using feedforward mechanisms, organisms can exploit correlations in environmental variables to prepare for anticipated future changes. Strategies to obtain, store and act on information about the conditional nature of future events are advantageous and are evidenced in widespread phenotypes such as circadian clocks, social behaviour, diapause and migrations. Humans are altering the ways in which the environment fluctuates, causing correlations between environmental variables to become decoupled, decreasing the reliability of cues. Human-induced environmental change is also altering sensory environments and the ability of organisms to detect cues. Recognizing that living systems combine feedback and feedforward processes is essential to understanding their responses to current and future regimes of environmental fluctuations. This article is part of the theme issue ‘Integrative research perspectives on marine conservation’.