Ecological Monographs最新文献

{"title":"Abiotic and biotic drivers of tree trait effects on soil microbial biomass and soil carbon concentration","authors":"Rémy Beugnon,&nbsp;Wensheng Bu,&nbsp;Helge Bruelheide,&nbsp;Andréa Davrinche,&nbsp;Jianqing Du,&nbsp;Sylvia Haider,&nbsp;Matthias Kunz,&nbsp;Goddert von Oheimb,&nbsp;Maria D. Perles-Garcia,&nbsp;Mariem Saadani,&nbsp;Thomas Scholten,&nbsp;Steffen Seitz,&nbsp;Bala Singavarapu,&nbsp;Stefan Trogisch,&nbsp;Yanfen Wang,&nbsp;Tesfaye Wubet,&nbsp;Kai Xue,&nbsp;Bo Yang,&nbsp;Simone Cesarz,&nbsp;Nico Eisenhauer","doi":"10.1002/ecm.1563","DOIUrl":"10.1002/ecm.1563","url":null,"abstract":"<p>Forests are ecosystems critical to understanding the global carbon budget, due to their carbon sequestration potential in both aboveground and belowground compartments, especially in species-rich forests. Soil carbon sequestration is strongly linked to soil microbial communities, and this link is mediated by the tree community, likely due to modifications of microenvironmental conditions (i.e., biotic conditions, soil properties, and microclimate). We studied soil carbon concentration and the soil microbial biomass of 180 local neighborhoods along a gradient of tree species richness ranging from 1 to 16 tree species per plot in a Chinese subtropical forest experiment (BEF-China). Tree productivity and different tree functional traits were measured at the neighborhood level. We tested the effects of tree productivity, functional trait identity, and dissimilarity on soil carbon concentrations, and their mediation by the soil microbial biomass and microenvironmental conditions. Our analyses showed a strong positive correlation between soil microbial biomass and soil carbon concentrations. In addition, soil carbon concentration increased with tree productivity and tree root diameter, while it decreased with litterfall C:N content. Moreover, tree productivity and tree functional traits (e.g., fungal root association and litterfall C:N ratio) modulated microenvironmental conditions with substantial consequences for soil microbial biomass. We also showed that soil history and topography should be considered in future experiments and tree plantations, as soil carbon concentrations were higher at sites where historical (i.e., at the beginning of the experiment) carbon concentrations were high, themselves being strongly affected by the topography. Altogether, these results implied that the quantification of the different soil carbon pools is critical for understanding microbial community–soil carbon stock relationships and their dependence on tree diversity and microenvironmental conditions.</p>","PeriodicalId":11505,"journal":{"name":"Ecological Monographs","volume":"93 2","pages":""},"PeriodicalIF":6.1,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ecm.1563","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49043890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interspecific differences in microhabitat use expose insects to contrasting thermal mortality","authors":"Maria Vives-Ingla,&nbsp;Javier Sala-Garcia,&nbsp;Constantí Stefanescu,&nbsp;Armand Casadó-Tortosa,&nbsp;Meritxell Garcia,&nbsp;Josep Peñuelas,&nbsp;Jofre Carnicer","doi":"10.1002/ecm.1561","DOIUrl":"10.1002/ecm.1561","url":null,"abstract":"<p>Ecotones linking open and forested habitats contain multiple microhabitats with varying vegetal structures and microclimatic regimes. Ecotones host many insect species whose development is intimately linked to the microclimatic conditions where they grow (e.g., the leaves of their host plants and the surrounding air). Yet microclimatic heterogeneity at these fine scales and its effects on insects remain poorly quantified for most species. Here we studied how interspecific differences in the use of microhabitats across ecotones lead to contrasting thermal exposure and survival costs between two closely-related butterflies (<i>Pieris napi</i> and <i>P. rapae</i>). We first assessed whether butterflies selected different microhabitats to oviposit and quantified the thermal conditions at the microhabitat and foliar scales. We also assessed concurrent changes in the quality and availability of host plants. Finally, we quantified larval time of death under different experimental temperatures (thermal death time [TDT] curves) to predict their thermal mortality considering both the intensity and the duration of the microclimatic heat challenges in the field. We identified six processes determining larval thermal exposure at fine scales associated with butterfly oviposition behavior, canopy shading, and heat and water fluxes at the soil and foliar levels. Leaves in open microhabitats could reach temperatures 3–10°C warmer than the surrounding air while more closed microhabitats presented more buffered and homogeneous temperatures. Interspecific differences in microhabitat use matched the TDT curves and the thermal mortality in the field. Open microhabitats posed acute heat challenges that were better withstood by the thermotolerant butterfly, <i>P. rapae</i>, where the species mainly laid their eggs. Despite being more thermosensitive, <i>P. napi</i> was predicted to present higher survivals than <i>P. rapae</i> due to the thermal buffering provided by their selected microhabitats. However, its offspring could be more vulnerable to host-plant scarcity during summer drought periods. Overall, the different interaction of the butterflies with microclimatic and host-plant variation emerging at fine scales and their different thermal sensitivity posed them contrasting heat and resource challenges. Our results contribute to setting a new framework that predicts insect vulnerability to climate change based on their thermal sensitivity and the intensity, duration, and accumulation of their heat exposure.</p>","PeriodicalId":11505,"journal":{"name":"Ecological Monographs","volume":"93 2","pages":""},"PeriodicalIF":6.1,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ecm.1561","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49490468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Partner fidelity and environmental filtering preserve stage-specific turtle ant gut symbioses for over 40 million years","authors":"Yi Hu,&nbsp;Catherine L. D'Amelio,&nbsp;Benoît Béchade,&nbsp;Christian S. Cabuslay,&nbsp;Piotr Łukasik,&nbsp;Jon G. Sanders,&nbsp;Shauna Price,&nbsp;Emily Fanwick,&nbsp;Scott Powell,&nbsp;Corrie S. Moreau,&nbsp;Jacob A. Russell","doi":"10.1002/ecm.1560","DOIUrl":"https://doi.org/10.1002/ecm.1560","url":null,"abstract":"Sustaining beneficial gut symbioses presents a major challenge for animals, including holometabolous insects. Social insects may meet such challenges through partner fidelity, aided by behavioral symbiont transfer and transgenerational inheritance through colony founders. We address such potential through colony-wide explorations across 13 eusocial, holometabolous insect species in the ant genus Cephalotes . Through amplicon sequencing, we show that previously characterized worker microbiomes are conserved in sol-dier castes, that adult microbiomes exhibit trends of phylosymbiosis","PeriodicalId":11505,"journal":{"name":"Ecological Monographs","volume":"93 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2022-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ecm.1560","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50123837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Climate-mediated population dynamics of a migratory songbird differ between the trailing edge and range core","authors":"William B. Lewis,&nbsp;Robert J. Cooper,&nbsp;Richard B. Chandler,&nbsp;Ryan W. Chitwood,&nbsp;Mason H. Cline,&nbsp;Michael T. Hallworth,&nbsp;Joanna L. Hatt,&nbsp;Jeff Hepinstall-Cymerman,&nbsp;Sara A. Kaiser,&nbsp;Nicholas L. Rodenhouse,&nbsp;T. Scott Sillett,&nbsp;Kirk W. Stodola,&nbsp;Michael S. Webster,&nbsp;Richard T. Holmes","doi":"10.1002/ecm.1559","DOIUrl":"10.1002/ecm.1559","url":null,"abstract":"<p>Understanding the demographic drivers of range contractions is important for predicting species' responses to climate change; however, few studies have examined the effects of climate change on survival and recruitment across species' ranges. We show that climate change can drive trailing edge range contractions through the effects on apparent survival, and potentially recruitment, in a migratory songbird. We assessed the demographic drivers of trailing edge range contractions using a long-term demography dataset for the black-throated blue warbler (<i>Setophaga caerulescens</i>) collected across elevational climate gradients at the trailing edge and core of the breeding range. We used a Bayesian hierarchical model to estimate the effect of climate change on apparent survival and recruitment and to forecast population viability at study plots through 2040. The trailing edge population at the low-elevation plot became locally extinct by 2017. The local population at the mid-elevation plot at the trailing edge gradually declined and is predicted to become extirpated by 2040. Population declines were associated with warming temperatures at the mid-elevation plot, although results were more equivocal at the low-elevation plot where we had fewer years of data. Population density was stable or increasing at the range core, although warming temperatures are predicted to cause population declines by 2040 at the low-elevation plot. This result suggests that even populations within the geographic core of the range are vulnerable to climate change. The demographic drivers of local population declines varied between study plots, but warming temperatures were frequently associated with declining rates of population growth and apparent survival. Declining apparent survival in our study system is likely to be associated with increased adult emigration away from poor-quality habitats. Our results suggest that demographic responses to warming temperatures are complex and dependent on local conditions and geographic range position, but spatial variation in population declines is consistent with the climate-mediated range shift hypothesis. Local populations of black-throated blue warblers near the warm-edge range boundary at low latitudes and low elevations are likely to be the most vulnerable to climate change, potentially leading to local extirpation and range contractions.</p>","PeriodicalId":11505,"journal":{"name":"Ecological Monographs","volume":"93 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://esajournals.onlinelibrary.wiley.com/doi/epdf/10.1002/ecm.1559","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9642160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The geographic footprint of mutualism: How mutualists influence species' range limits","authors":"Joshua C. Fowler,&nbsp;Marion L. Donald,&nbsp;Judith L. Bronstein,&nbsp;Tom E. X. Miller","doi":"10.1002/ecm.1558","DOIUrl":"10.1002/ecm.1558","url":null,"abstract":"<p>Understanding mechanisms that generate range limits is central to knowing why species are found where they are and how they will respond to environmental change. There is growing awareness that biotic interactions play an important role in generating range limits. However, current theory and data overwhelmingly focus on abiotic drivers and antagonistic interactions. Here we explore the effect that mutualists have on their partner's range limits: the geographic “footprint” of mutualism. This footprint arises from two general processes: modification of a partner's niche through environment-dependent fitness effects and, for a subset of mutualisms, dispersal opportunities that lead suitable habitats to be filled. We developed a conceptual framework that organizes different footprints of mutualism and the underlying mechanisms that shape them, and evaluated supporting empirical evidence from the primary literature. In the available literature, we found that the fitness benefits and dispersal opportunities provided by mutualism can extend species' ranges; conversely, the absence of mutualism can constrain species from otherwise suitable regions of their range. Most studies found that the footprint of mutualism is driven by changes in the frequency of mutualist partners from range core to range edge, whereas fewer found changes in interaction outcomes, the diversity of partners, or varying sensitivities of fitness to the effects of mutualists. We discuss these findings with respect to specialization, dependence, and intimacy of mutualism. Much remains unknown about the geographic footprint of mutualisms, leaving fruitful areas for future work. A particularly important future direction is to explore the role of mutualism during range shifts under global change, including the promotion of shifts at leading edges and persistence at trailing edges.</p>","PeriodicalId":11505,"journal":{"name":"Ecological Monographs","volume":"93 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43541236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cross validation for model selection: A review with examples from ecology","authors":"Luke A. Yates,&nbsp;Zach Aandahl,&nbsp;Shane A. Richards,&nbsp;Barry W. Brook","doi":"10.1002/ecm.1557","DOIUrl":"10.1002/ecm.1557","url":null,"abstract":"<p>Specifying, assessing, and selecting among candidate statistical models is fundamental to ecological research. Commonly used approaches to model selection are based on predictive scores and include information criteria such as Akaike's information criterion, and cross validation. Based on data splitting, cross validation is particularly versatile because it can be used even when it is not possible to derive a likelihood (e.g., many forms of machine learning) or count parameters precisely (e.g., mixed-effects models). However, much of the literature on cross validation is technical and spread across statistical journals, making it difficult for ecological analysts to assess and choose among the wide range of options. Here we provide a comprehensive, accessible review that explains important—but often overlooked—technical aspects of cross validation for model selection, such as: bias correction, estimation uncertainty, choice of scores, and selection rules to mitigate overfitting. We synthesize the relevant statistical advances to make recommendations for the choice of cross-validation technique and we present two ecological case studies to illustrate their application. In most instances, we recommend using exact or approximate leave-one-out cross validation to minimize bias, or otherwise <i>k</i>-fold with bias correction if <i>k</i> &lt; 10. To mitigate overfitting when using cross validation, we recommend calibrated selection via our recently introduced modified one-standard-error rule. We advocate for the use of predictive scores in model selection across a range of typical modeling goals, such as exploration, hypothesis testing, and prediction, provided that models are specified in accordance with the stated goal. We also emphasize, as others have done, that inference on parameter estimates is biased if preceded by model selection and instead requires a carefully specified single model or further technical adjustments.</p>","PeriodicalId":11505,"journal":{"name":"Ecological Monographs","volume":"93 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2022-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ecm.1557","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47711101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Scientists' warning on climate change and insects","authors":"Jeffrey A. Harvey,&nbsp;Kévin Tougeron,&nbsp;Rieta Gols,&nbsp;Robin Heinen,&nbsp;Mariana Abarca,&nbsp;Paul K. Abram,&nbsp;Yves Basset,&nbsp;Matty Berg,&nbsp;Carol Boggs,&nbsp;Jacques Brodeur,&nbsp;Pedro Cardoso,&nbsp;Jetske G. de Boer,&nbsp;Geert R. De Snoo,&nbsp;Charl Deacon,&nbsp;Jane E. Dell,&nbsp;Nicolas Desneux,&nbsp;Michael E. Dillon,&nbsp;Grant A. Duffy,&nbsp;Lee A. Dyer,&nbsp;Jacintha Ellers,&nbsp;Anahí Espíndola,&nbsp;James Fordyce,&nbsp;Matthew L. Forister,&nbsp;Caroline Fukushima,&nbsp;Matthew J. G. Gage,&nbsp;Carlos García-Robledo,&nbsp;Claire Gely,&nbsp;Mauro Gobbi,&nbsp;Caspar Hallmann,&nbsp;Thierry Hance,&nbsp;John Harte,&nbsp;Axel Hochkirch,&nbsp;Christian Hof,&nbsp;Ary A. Hoffmann,&nbsp;Joel G. Kingsolver,&nbsp;Greg P. A. Lamarre,&nbsp;William F. Laurance,&nbsp;Blas Lavandero,&nbsp;Simon R. Leather,&nbsp;Philipp Lehmann,&nbsp;Cécile Le Lann,&nbsp;Margarita M. López-Uribe,&nbsp;Chun-Sen Ma,&nbsp;Gang Ma,&nbsp;Joffrey Moiroux,&nbsp;Lucie Monticelli,&nbsp;Chris Nice,&nbsp;Paul J. Ode,&nbsp;Sylvain Pincebourde,&nbsp;William J. Ripple,&nbsp;Melissah Rowe,&nbsp;Michael J. Samways,&nbsp;Arnaud Sentis,&nbsp;Alisha A. Shah,&nbsp;Nigel Stork,&nbsp;John S. Terblanche,&nbsp;Madhav P. Thakur,&nbsp;Matthew B. Thomas,&nbsp;Jason M. Tylianakis,&nbsp;Joan Van Baaren,&nbsp;Martijn Van de Pol,&nbsp;Wim H. Van der Putten,&nbsp;Hans Van Dyck,&nbsp;Wilco C. E. P. Verberk,&nbsp;David L. Wagner,&nbsp;Wolfgang W. Weisser,&nbsp;William C. Wetzel,&nbsp;H. Arthur Woods,&nbsp;Kris A. G. Wyckhuys,&nbsp;Steven L. Chown","doi":"10.1002/ecm.1553","DOIUrl":"10.1002/ecm.1553","url":null,"abstract":"<p>Climate warming is considered to be among the most serious of anthropogenic stresses to the environment, because it not only has direct effects on biodiversity, but it also exacerbates the harmful effects of other human-mediated threats. The associated consequences are potentially severe, particularly in terms of threats to species preservation, as well as in the preservation of an array of ecosystem services provided by biodiversity. Among the most affected groups of animals are insects—central components of many ecosystems—for which climate change has pervasive effects from individuals to communities. In this contribution to the scientists' warning series, we summarize the effect of the gradual global surface temperature increase on insects, in terms of physiology, behavior, phenology, distribution, and species interactions, as well as the effect of increased frequency and duration of extreme events such as hot and cold spells, fires, droughts, and floods on these parameters. We warn that, if no action is taken to better understand and reduce the action of climate change on insects, we will drastically reduce our ability to build a sustainable future based on healthy, functional ecosystems. We discuss perspectives on relevant ways to conserve insects in the face of climate change, and we offer several key recommendations on management approaches that can be adopted, on policies that should be pursued, and on the involvement of the general public in the protection effort.</p>","PeriodicalId":11505,"journal":{"name":"Ecological Monographs","volume":"93 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2022-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ecm.1553","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44323008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative biogeography: Decreasing and more variable dynamics of critical species in an iconic meta-ecosystem","authors":"Bruce A. Menge,&nbsp;Jonathan W. Robinson,&nbsp;Brittany N. Poirson,&nbsp;Sarah A. Gravem","doi":"10.1002/ecm.1556","DOIUrl":"10.1002/ecm.1556","url":null,"abstract":"<p>Ecosystem stability has intrigued ecologists for decades, and the realization that the global climate was changing has sharpened and focused this interest. One possible early warning signal of decreasing stability is increasing variability in ecosystems over time with increasing climate variability. Determining climate change effects on community stability, however, requires long-term studies of structure and underlying dynamics, including bottom-up and top-down effects in natural ecosystems. Although relevant datasets were rare in the early years of community ecology, such information has increased in recent decades. We investigated spatiotemporal changes in mean and variability of ecological subsidies (nutrients, phytoplankton, prey colonization), performance metrics of a dominant space occupier (mussels) and its primary predator (sea stars), and sea star predation rates on mussels in relation to climatic oscillations, temperature, and disease on rocky shores. The research involved annually repeated multiyear (~1999–2018), multisite (13 sites nested within five regions along ~260 km of the Oregon coast) observations, measurements, and experiments. We analyzed associations between environmental variables and ecological performance of key elements of the sea star-mussel-dominated mid intertidal system. We found that upwelling declined in some regions, but became more variable across all study regions. Air and water temperatures oscillated, but their mean and variation increased through time, with peak values coinciding with the 2014–2016 combined El Niño and Marine Heat Wave. Ecological subsidies generally declined during the study period but increased in variability. Excepting growth rate, mussel (<i>Mytilus californianus</i>) performance (condition index, reproductive output) generally decreased and became more variable. Primarily due to a sea star wasting epidemic, reproductive output of the top predator <i>Pisaster ochraceus</i> decreased and became more variable, and predation rate on mussels decreased. Analyses indicated that the primary drivers of these changes were temperature-related environmental factors. As declining means and increasing variability of ecological performances can typify destabilizing ecosystems, and environmental trends are toward ever more stressful conditions, the outlook for this iconic ecosystem is discouraging. Immediate and rapid action to mitigate and ultimately reverse climate change likely is the only option available to prevent an irreversible shift in the future of this, and most other ecosystems.</p>","PeriodicalId":11505,"journal":{"name":"Ecological Monographs","volume":"93 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47491920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intraspecific trait variability is a key feature underlying high Arctic plant community resistance to climate warming","authors":"Ingibjörg S. Jónsdóttir,&nbsp;Aud H. Halbritter,&nbsp;Casper T. Christiansen,&nbsp;Inge H. J. Althuizen,&nbsp;Siri V. Haugum,&nbsp;Jonathan J. Henn,&nbsp;Katrín Björnsdóttir,&nbsp;Brian Salvin Maitner,&nbsp;Yadvinder Malhi,&nbsp;Sean T. Michaletz,&nbsp;Ruben E. Roos,&nbsp;Kari Klanderud,&nbsp;Hanna Lee,&nbsp;Brian J. Enquist,&nbsp;Vigdis Vandvik","doi":"10.1002/ecm.1555","DOIUrl":"10.1002/ecm.1555","url":null,"abstract":"<p>In the high Arctic, plant community species composition generally responds slowly to climate warming, whereas less is known about the community functional trait responses and consequences for ecosystem functioning. The slow species turnover and large distribution ranges of many Arctic plant species suggest a significant role of intraspecific trait variability in functional responses to climate change. Here we compare taxonomic and functional community compositional responses to a long-term (17-year) warming experiment in Svalbard, Norway, replicated across three major high Arctic habitats shaped by topography and contrasting snow regimes. We observed taxonomic compositional changes in all plant communities over time. Still, responses to experimental warming were minor and most pronounced in the drier habitats with relatively early snowmelt timing and long growing seasons (<i>Cassiope</i> and <i>Dryas</i> heaths). The habitats were clearly separated in functional trait space, defined by 12 size- and leaf economics-related traits, primarily due to interspecific trait variation. Functional traits also responded to experimental warming, most prominently in the <i>Dryas</i> heath and mostly due to intraspecific trait variation. Leaf area and mass increased and leaf δ¹⁵N decreased in response to the warming treatment. Intraspecific trait variability ranged between 30% and 71% of the total trait variation, reflecting the functional resilience of those communities, dominated by long-lived plants, due to either phenotypic plasticity or genotypic variation, which most likely underlies the observed resistance of high Arctic vegetation to climate warming. We further explored the consequences of trait variability for ecosystem functioning by measuring peak season CO₂ fluxes. Together, environmental, taxonomic, and functional trait variables explained a large proportion of the variation in net ecosystem exchange (NEE), which increased when intraspecific trait variation was accounted for. In contrast, even though ecosystem respiration and gross ecosystem production both increased in response to warming across habitats, they were mainly driven by the direct kinetic impacts of temperature on plant physiology and biochemical processes. Our study shows that long-term experimental warming has a modest but significant effect on plant community functional trait composition and suggests that intraspecific trait variability is a key feature underlying high Arctic ecosystem resistance to climate warming.</p>","PeriodicalId":11505,"journal":{"name":"Ecological Monographs","volume":"93 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ecm.1555","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43000659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Applying the structural causal model framework for observational causal inference in ecology","authors":"Suchinta Arif,&nbsp;M. Aaron MacNeil","doi":"10.1002/ecm.1554","DOIUrl":"https://doi.org/10.1002/ecm.1554","url":null,"abstract":"<p>Ecologists are often interested in answering causal questions from observational data but generally lack the training to appropriately infer causation. When applying statistical analysis (e.g., generalized linear model) on observational data, common statistical adjustments can often lead to biased estimates between variables of interest due to processes such as confounding, overcontrol, and collider bias. To overcome these limitations, we present an overview of structural causal modeling (SCM), an emerging causal inference framework that can be used to determine cause-and-effect relationships from observational data. The SCM framework uses directed acyclic graphs (DAGs) to visualize researchers' assumptions about the causal structure of a system or process under study. Following this, a DAG-based graphical rule known as the backdoor criterion can be applied to determine statistical adjustments (or lack thereof) required to determine causal relationships from observational data. In the presence of unobserved confounding variables, an additional rule called the frontdoor criterion can be employed to determine causal effects. Here, we use simulated ecological examples to review how the backdoor and frontdoor criteria can return accurate causal estimates between variables of interest, as well as how biases can arise when these criteria are not used. We further provide an overview of studies that have applied the SCM framework in ecology. SCM, along with its application of DAGs, has been widely used in other disciplines to make valid causal inferences from observational data. Their use in ecology holds tremendous potential for quantifying causal relationships and investigating a range of ecological questions without randomized experiments.</p>","PeriodicalId":11505,"journal":{"name":"Ecological Monographs","volume":"93 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2022-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50141322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}