Ecological Monographs最新文献

Grassy biomes (savanna and grasslands) are globally extensive and host a unique biodiversity that is of central importance to human livelihoods. We focus here on the island of Madagascar—a microcosm of the global tropics, covered in 80% grassy biomes—to illustrate how transdisciplinary approaches to research can clarify ecosystem dynamics, from evolutionary history to human land use. Research on Madagascar's human-environment interactions has sparked debates about the role of past and current land use in shaping grassy biomes (e.g., pastoralism, cultivation, fire use). These debates echo those in other regions globally, and highlight obstacles to understanding and supporting both ecosystem and livelihood resilience. Like many tropical biodiversity hotspots, Madagascar faces converging challenges that can be aided by transdisciplinary research, including food and health insecurity, economic inequities, biodiversity loss, climate change, land conversion, and limited resource access. We present a framework to guide transdisciplinary research centered on improved understanding and management of grassy biomes on Madagascar by: (1) establishing a globally common terminology; (2) summarizing data contributions and scientific knowledge gaps relating to Madagascar's grassy biomes; (3) identifying priority research questions for Madagascar with applicability in other regions; and (4) highlighting transdisciplinary, inclusive approaches to research that can co-benefit people and the ecosystems with which they interact.

Variability in traits within species (intraspecific trait variability; ITV) has attracted increased interest in functional ecology, as it can profoundly influence the detection of functional trait patterns, calculations of functional diversity (FD), and assessments of ecosystem functioning. This interest stems from the recognition that species are not homogeneous entities but rather mosaics of individuals with varying trait values. Since multiple methods have emerged to explicitly incorporate ITV into FD calculations, accurate estimates and meaningful interpretations of FD would benefit from a more explicit methodological framework to account for ITV. Some methods treat individuals as the unit of analysis, while others characterize trait distributions around species means. Ecologists navigating this landscape of methods may face challenges in selecting the most appropriate approach to address their research questions, which also depend on data availability. Here, we synthesize the current literature to provide guidelines regarding how and when to use the various available methods to quantify ITV in biological systems and integrate it within FD. We also provide a toolbox to calculate the presented metrics in the form of implemented R code. As a case study, we computed correlations between FD metrics on simulated assemblages with varying degrees of trait variability. Our findings suggest that the choice of FD metric should be guided primarily by the ecological question being addressed and, to a lesser extent, by the number and types of traits, although the type of data available might also impose some limitations. Simulations revealed strong correlations among FD metrics that account for ITV, particularly those indicating the size of the occupied functional trait space. Furthermore, ITV seems to be more important for increasing the functional volume than between-species variability, while regularity metrics (how even species abundances are distributed in the functional trait space) were nearly insensitive to changes in between- or within-species variability. As evidence accumulates and shows how ITV is key to shaping species' fitness and distributions as well as affecting ecosystem functioning, this synthesis will serve as a conceptual and practical tool ideally inspiring and guiding researchers to integrate ITV in FD analyses.

Many organisms with broad distributions show latitudinal variations in morphological phenotypes and life history traits, such as body size and phenology, in relation to environmental changes such as temperature along latitude. Such variations have usually been considered the result of natural selection, but sexual selection may also lead to these latitudinal patterns. Although a recent study has shown the latitudinal pattern in the strength of male–male competition in medaka fish, such a latitudinal pattern related to sexual selection is rarely known in other organisms. Here, we show the latitudinal pattern of a reproductive trait driven by sexual selection in the Japanese black salamander (Hynobius nigrescens), where snout-vent length (SVL) in males predicts the outcome of male–male competition over egg sacs. First, we conducted phylogenetic analyses to examine the phylogenetic pattern along latitude. From the constructed phylogenetic tree, this species was split into five lineages that were roughly divided along latitude. We also used field surveys to examine whether the operational sex ratio (OSR: an index of the strength of male–male competition) varies across lineages with latitude. We found that the OSR was more biased toward males in a lineage distributed at lower latitudes due to its longer breeding period. We measured the SVLs of collected samples to determine if the latitudinal pattern also exists for SVL. Indeed, male SVLs were longer in lineages distributed at lower latitudes, whereas those in females did not differ among lineages. Our common garden experiment also showed that the individuals from a lineage distributed at lower latitudes had longer SVLs even when they grew under the same environmental conditions, suggesting that the latitudinal pattern in SVL is genetically determined. These results suggest that males at lower latitudes have evolved longer SVLs, driven by stronger male–male competition. Our study provides the first example, to the best of our knowledge, of a latitudinal pattern driven by sexual selection and its evolutionary determinant in detail in the wild.

Teittinen, Anette, Miska Luoto, Petteri Muukkonen, Maria-Katariina Myyry, Maria Reiman, Michael Scherer-Lorenzen, and Janne Soininen. 2025. “Cross-Boundary Connections of Biodiversity and Ecosystem Functioning in Boreal Ecosystems.” Ecological Monographs 95(1): e70013. 10.1002/ecm.70013.

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Maes, Tim, Julie Verheyen, Bruno Senghor, Aspire Mudavanhu, Ruben Schols, Bart Hellemans, Enora Geslain, Filip A. M. Volckaert, Hugo F. Gante, and Tine Huyse. 2025. “First Evidence of a Genetic Basis for Thermal Adaptation in a Schistosome Host Snail.” Ecological Monographs 95(1): e70006. 10.1002/ecm.70006.

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Open Access funding was provided by Universitat Innsbruck/KEMÖ.

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The addition of terrestrial inputs to the ocean can have cascading impacts on coastal biogeochemistry by directly altering the water chemistry and indirectly changing ecosystem metabolism, which also influences water chemistry. Here, we use submarine groundwater discharge (SGD) as a model system to examine the direct geochemical and indirect biologically mediated effects of terrestrial nutrient subsidies on a fringing coral reef. We hypothesize that the addition of new solutes from SGD alters ecosystem metabolic processes including net ecosystem production and calcification, thereby changing the patterns of uptake and release of carbon by benthic organisms. SGD is a common land–sea connection that delivers terrestrially sourced nutrients, carbon dioxide, and organic matter to coastal ecosystems. Our research was conducted at two distinct coral reefs in Moʻorea, French Polynesia, characterized by contrasting flow regimes and SGD biogeochemistry. Using a Bayesian structural equation model, our research elucidates the direct geochemical and indirect biologically mediated effects of SGD on both dissolved organic and inorganic carbon pools. We reveal that SGD-derived nutrients enhance both net ecosystem production and respiration. Furthermore, the study demonstrates that SGD-induced alterations in net ecosystem production significantly influence pH dynamics, ultimately impacting net ecosystem calcification. Notably, the study underscores the context-dependent nature of these cascading direct and indirect effects resulting from SGD, with flow conditions and the composition of the terrestrial inputs playing pivotal roles. Our research provides valuable insights into the interplay between terrestrial inputs and coral reef ecosystems, advancing our understanding of coastal carbon cycling and the broader implications of allochthonous inputs on ecosystem functioning.

Animal populations in arid environments, where extreme temperatures and erratic rainfall are normal, are particularly vulnerable to climate change. While numerous studies have examined the effects of temperature and rainfall on the breeding success and survival of arid-zone species, the mechanistic pathways linking climate variation to demography remain poorly described for most species. Using long-term data from meerkats (Suricata suricatta) in the Kalahari Desert, we show that increases in rainfall and primary productivity (as measured by normalized difference vegetation index) were associated with improved foraging success, daily body mass gain, and body condition, which in turn contributed to enhanced breeding success and survival. Conversely, high summer temperatures were associated with reduced foraging performance and body condition. Foraging efficiency declined when daily maximum summer temperatures exceeded 35°C, and at temperatures above 37°C, diurnal mass gains often failed to offset overnight mass losses. While high temperatures had short-term detrimental effects, runs of hot days were relatively infrequent and often coincided with periods of high primary productivity. As a result, individuals were rarely in poor condition during the hottest periods of the year, suggesting that they could recover any mass lost on hot days during subsequent cooler periods. Only when high temperatures persisted alongside low primary productivity did body condition drop sharply. Although temperature variation has not yet affected the demography of our meerkat population as strongly as rainfall variation, further warming in the region and the potential for more frequent and severe hot droughts are likely to have major implications for the species' distribution and persistence. Our study emphasizes the need to consider both rainfall and temperature variations across seasons, as well as their interactions, to better understand and predict the impacts of climate change on arid-zone animals. It also demonstrates the value of long-term, high-resolution behavioral and physiological data, including frequent, year-round weighing of animals, in establishing causal links between climate and demography.

Trait-based ecology, a prominent research field identifying traits linked to the distribution and interactions of organisms and their impact on ecosystem functioning, has flourished in the last three decades. Yet, the field still grapples with critical challenges, broadly framed as Raunkiæran shortfalls. Recognizing and interconnecting these limitations is vital for designing and prioritizing research objectives and mainstreaming trait-based approaches across a variety of organisms, trophic levels, and biomes. This strategic review scrutinizes eight major limitations within trait-based ecology, spanning scales from organisms to the entire biosphere. Challenges range from defining and measuring traits (SF 1), exploring intraspecific variability within and across individuals and populations (SF 2), understanding the complex relationships between trait variation and fitness (SF 3), and discerning trait variations with underlying evolutionary patterns (SF 4). This review extends to community assembly (SF 5), ecosystem functioning and multitrophic relationships (SFs 6 and 7), and global repositories and scaling (SF 8). At the core of trait-based ecology lies the ambition of scaling up processes from individuals to ecosystems by exploring the ecological strategies of organisms and connecting them to ecosystem functions across multiple trophic levels. Achieving this goal necessitates addressing key limitations embedded in the foundations of trait-based ecology. After identifying key SFs, we propose pathways for advancing trait-based ecology, fortifying its robustness, and unlocking its full potential to significantly contribute to ecological understanding and biodiversity conservation. This review underscores the significance of systematically evaluating the performance of organisms in standardized conditions, encompassing their responses to environmental variation and effects on ecosystems. This approach aims to bridge the gap between easily measurable traits, species ecological strategies, their demography, and their combined impacts on ecosystems.

Biodiversity is a central concept in ecology and biology. Its underpinnings are multifaceted and complex and involve multiple spatiotemporal scales, and many ways of measuring relevant characteristics. Its comprehensive understanding requires a framework on which to organize concepts and associated metrics. The analysis of biodiversity is based on combinations of two types of units: study units (i.e., the inferential domain in time and space that characterizes sampling) and measurement units (i.e., metrics). We provide an integrated framework for the units of study derived from three aspects of organisms: their spatiotemporal relationships (geography), their evolutionary relationships (phylogeny), and their ecological relationships based on their requirements and effects (niche). We systematize the units of measurement based on four types of data (identity, abundance, phylogeny, traits), two properties of those data (magnitude and variability), and three approaches for their measurement (total, pairwise, nearest neighbor). Together, they define 14 basic elements that can be combined in many ways and be subject to various mathematical operations. The result is 130 different metrics, including those in the literature and those developed herein. We propose standardized symbols for these metrics and provide formulas using standard notations for their parameters. Importantly, we show how our framework can be used to align study units and measurement units with questions concerning the causes and consequences of biodiversity. We provide case studies on bats in Peru and trees in the eastern United States to ecological gradient theory, niche theory, and theory about relationships between biodiversity and productivity, and we discuss which metrics might be most appropriate in tests of island biogeography theory and the dilution effect of pathogen transmission. Our key recommendations are that researchers should: (1) harmonize study unit properties with explicitly defined questions, (2) couple metric properties with underlying processes, and (3) compare metrics with similar properties. By providing an overarching framework that clearly delineates units of study and units of measurement, we hope to ensure that appropriate data are applied to particular scientific questions, especially those of a comparative nature, thereby leading to robust conclusions of theoretical import or practical use in management or conservation.

Instream structures such as dams and weirs create artificial barriers to the passage of riverine fish, fragmenting their communities and contributing to global declines in freshwater fish biodiversity. Preventing further declines requires the remediation of barriers to restore fish passage, but analysis of fragmented fish communities is necessary to prioritize locations and fish taxa for remediation. Additionally, the potential for high flow events to facilitate barrier drown-out and reduce fragmentation remains unresolved. We used a meta-regression analysis to investigate the severity of fish fragmentation in relation to barrier features, fish traits, and river flows, quantifying fragmentation with a novel log response ratio metric reflecting the asymmetry of fish populations around barriers. We discovered that high barriers, barriers which separate different sized habitats, and clusters of sequential barriers cause more severe fragmentation and should be prioritized for remediation. Currently, barrier remediation is focused on improving passage for mobile fishes, but taxa which migrate short distances and have poor swimming performance were most fragmented, suggesting efforts are warranted to improve passage for less vagile fishes. We found evidence that fragmentation was reduced by large river flows which spill onto the floodplain and provide additional connectivity around barriers, particularly in highly regulated sections of stream with many sequential barriers. The findings of this study can be applied to improve the management of fish passage in rivers, an area of increasing relevance with the worsening discontinuity of rivers due to climate change and the continued construction of barriers.