Adaptive and Plastic Responses to Environmental Variation: Introduction to a Virtual Symposium in The Biological Bulletin.

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Previous articleNext article FreeAdaptive and Plastic Responses to Environmental Variation: Introduction to a Virtual Symposium in The Biological BulletinPatrick J. Krug, John P. Wares, and Jonathan D. AllenPatrick J. Krug1Department of Biological Sciences, Cal State Los Angeles, Los Angeles, California 90032-8201*Email: [email protected]. Search for more articles by this author , John P. Wares2Department of Genetics, Odum School of Ecology, University of Georgia, Athens, Georgia 30602 Search for more articles by this author , and Jonathan D. Allen3Department of Biology, William & Mary, Williamsburg, Virginia 23187 Search for more articles by this author †Email: [email protected].‡Email: [email protected].PDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinked InRedditEmailQR Code SectionsMoreClimate change is rapidly restructuring communities and altering the distribution of biodiversity along coastlines worldwide. While many species have undergone range shifts to track their niche, other taxa may adapt to, or tolerate, the changing conditions in which they find themselves. Forecasting the biological responses of coastal systems to global change is critical, given the ecological disruption to diverse communities (Zhang et al., 2017. Proc. R. Soc. B Biol. Sci. 284: 20171772), the importance of their resources to global food security (Costello et al., 2020. Nature 588: 95–100), and the vulnerable ecosystem services provided by coastal taxa (He and Silliman, 2019. Curr. Biol. 29: R1021–R1035). However, such forecasting efforts are challenged by key differences between aquatic (marine and freshwater) and terrestrial organisms, including their life histories and physical properties of their respective environments (Pinsky et al., 2019. Nature 569: 108–111; Shlesinger and Loya, 2019. Science 365: 1002–1007).Over the past decade, researchers have built upon syntheses of prior efforts (e.g., Hoffmann and Sgro, 2011. Nature 470: 479–485; Doney et al., 2012. Annu. Rev. Mar. Sci. 4: 11–37) to better predict evolutionary responses of coastal ecosystems to climate change, leading to novel insights (Munday et al., 2013. Ecol. Lett. 12: 1488–1500; Baltar et al., 2019. Trends Ecol. Evol. 34: 1022–1033) and new research networks (e.g., https://rcn-ecs.github.io). However, challenges remain for exploring organismal and community responses to future conditions in aquatic habitats. To effectively model the response of diverse organisms to changing stress regimes, we require more exploration of phenotypic diversity across environments, a better understanding of heritable variation, and broader insights from non-model systems.Studies aimed at forecasting organismal response often measure performance under predicted future conditions in the laboratory (Wernberg et al., 2012. Glob. Change Biol. 18: 1491–1498). However, many coastal ecosystems are already characterized by locally varying or temporally fluctuating stressors, such as temperature, seawater chemistry, and salinity. Environmental variation and local adaptation are increasingly recognized as critical to predicting biotic responses to anthropogenic climate change (Vargas et al., 2017. Nat. Ecol. Evol. 1: 1–7; Marshall et al., 2021. Proc. R. Soc. B Biol. Sci. 288: 20202968). Thus, species that routinely experience fluctuating conditions should yield insight into the organismal and life-history responses that may evolve in the face of ongoing global change.This year, in an era in which virtual meetings gained new meaning, The Biological Bulletin “virtual symposium” addressed the question of how taxa cope with variable environments. Our aim was to draw together case studies of plasticity and local adaptation from diverse taxa that inhabit coastal habitats prone to rapid change or sharp gradients in physical stress. Contributors are united by their interest in studying how variable conditions affect phenotype and performance, but they also reflect a wide array of techniques and study systems to investigate questions organized around this theme. Work at the intersection of climate and biotic response often suggests that the evolutionary effects of environmental change may be idiosyncratic to the species, or even population, under study; however, our goal was to invite contributions from diverse scientists and systems so that broad categories of responses become apparent, and thus we begin to develop the ability to make general predictions.Three papers use different approaches to study plasticity in the early life stages of marine or estuarine species, examining how organisms may be buffered against environmental stress and variation by alternative phenotypes, maternal effects, or microbial associations. Caplins (pp. 55–64) takes a genomic approach to study developmental plasticity in the poecilogonous sea slug Alderia willowi, in which individuals produce either small feeding larvae with high dispersal potential or larger offspring with a reduced dispersal capacity and shorter planktonic life span. Caplins also identifies key candidate genes that may be partly responsible for resilience to seasonal and latitudinal shifts in salinity and temperature and links these to the distributions of congeneric Alderia species (see below). Hooks and Burgess (pp. 92–104) use behavioral and rearing experiments to show a different kind of plasticity affecting dispersal in the crown conch, Melongena corona. Although larvae emerged from broods as crawl-away pediveligers, up to half delayed competence and swam for brief but variable periods, retaining this ability to enhance dispersal for over three weeks. The likelihood of a swimming phase was related to cues of juvenile habitat and food, suggesting adaptive plasticity for individuals, depending on their assessment of local habitat quality, and substantial within-brood variation in offspring dispersal. Finally, the microbiome of coastal organisms is increasingly recognized as fundamental to their health and to the ecosystem services they provide, but we are just beginning to understand how climate change may impact the stability and composition of the holobiome (Trevathan-Tackett et al., 2019. Nat. Ecol. Evol. 3: 1509–1520). To begin to close this knowledge gap, Carrier et al. (pp. 65–76) characterize the microbiome associated with deep-sea larvae of diverse invertebrate taxa and contrast the microbial diversity between deep-sea and coastal taxa. The results provide not only the first widespread taxonomic survey of the larval microbiome between these habitats, which differ in their predicted environmental stability, and but also a platform for further study of how microbial symbionts may buffer early life stages against fluctuating conditions.Several contributions used experimental approaches to test the effects of variable versus static conditions and/or to compare the effects of high temperature versus low salinity stress on coastal species. Bock et al. (pp. 43–54) studied how temperature transitions evoke different juvenile phenotypes in Alligator mississippiensis, as a model for understanding temperature-dependent sex determination (TSD). Their study revealed different effects of fluctuating versus constant temperature regimes on numerous aspects of development, juvenile morphology, and metabolism, as well as on sex ratio. These findings will improve our understanding of how temperature changes are likely to influence population biology for organisms with TSD. Many species are shifting their distribution poleward as the climate changes, suggesting that we may glean important insight from trait trade-offs or biotic interactions with landscape features at dynamic range edges (Donelson et al., 2019. Philos. Trans. R. Soc. B Biol. Sci. 374: 20180186). Krug et al. (pp. 105–122) study environmental factors underlying the distributional limits and seasonal interchange between two estuarine sea slugs (Alderia spp.) that narrowly overlap along the coast of California. They report exceptional tolerance of near-freshwater salinities and high temperatures yet differences between the species that likely contribute to their geographic range limits. Links between phenotype and genotype can now be explored for these species, given the genomic work in Caplins (pp. 55–64). Late-season tolerance to stress indicated that local adaptation develops in range-edge populations of both Alderia spp., but trade-offs in temperature versus salinity response may constrain adaptation in this fluctuating environment. George et al. (pp. 77–91) also use an experimental approach to examine the influence of fluctuating temperature and salinity on larvae of two echinoderms from the northeastern Pacific. Larval feeding was suppressed following a low-salinity stress event for both the sea star Pisaster ochraceus and the sand dollar Dendraster excentricus, but the species differed in feeding capability during such an event, indicating subtle and potentially adaptive differences comporting with adult and larval environments.Two reviews focus on the response of foundation species that create critical coastal habitat to the emergence of novel stress combinations or to localized conditions. Hays et al. (pp. 16–29) synthesize evidence from molecular and experimental studies that together demonstrate local adaptation on a microgeographic scale in foundation species from habitats ranging from temperate salt marshes to tropical reefs. A newfound appreciation for microgeographic adaptation structured by depth gradients and mating systems may have profound consequences for efforts to conserve ecosystem engineers, from seagrass meadows to oyster and coral reefs. Similarly, fluctuating seawater chemistry is recognized as a key threat facing the biological diversity of marine systems, as large-scale shifts in ocean pH driven by climate change intensify the effects of upwelling and community metabolism at smaller spatial and temporal scales. David (pp. 4–15) reviews the interactive effects of ocean acidification and boring epibionts on bivalve shells and proposes ways to study effectively the response of shell-boring polychaetes to changing water chemistry and temperature regimes. This work highlights the synergistic threats that climate change and epibionts pose to economically important bivalve species that perform critical ecosystem services and build threatened reef habitat.While Hays et al. (pp. 16–29) highlight case studies of adaptation in natural populations, Kelly and Griffiths (pp. 30–42) review the work that has been done using experimental evolution approaches in marine systems. Although experimental evolution has long been an invaluable tool for exploring the adaptive potential of organisms under a chosen selective regime, the complex life cycles and specialized niches of many coastal species have made it challenging to apply artificial selection to such taxa. Kelly and Griffiths synthesize the growing body of work in this area and provide recommendations for applying these methods to assess the potential for adaptation to future ocean conditions.We hope that patterns that emerge from the wide array of systems analyzed in these contributions will inspire future research on the coping strategies and mechanisms that evolve in environments prone to frequent or unpredictable change. As climate change intensifies the stresses associated with life along coastlines, environmental and evolutionary biologists will increasingly need to understand and predict the drivers of, and constraints on, plasticity and local adaptation. To that end, we thank the contributors to this virtual symposium for their efforts to consider how the biology of their focal species interacts with the complex selective landscape of coastal habitats, for summarizing decades of work on questions critical to conserving threatened biodiversity, and for highlighting current knowledge gaps and, thus, directions for fruitful ongoing study. Previous articleNext article DetailsFiguresReferencesCited by The Biological Bulletin Volume 241, Number 1August 2021Adaptive and Plastic Responses to Environmental Variation Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/716013 Views: 632 HistoryReceived June 17, 2021Accepted June 17, 2021Published online July 20, 2021 © 2021 The University of ChicagoPDF download Crossref reports no articles citing this article.