Ecology and Evolution最新文献

Within marine systems, nutrient cycling is driven by physical forces that create predictable geochemical gradients. In turn, these gradients are reflected in spatially explicit and chemically distinct foodwebs, creating unique chemical signatures of consumer tissues that are useful for tracking the location and diet of consumers. In the eastern North Pacific, over the past three decades green sea turtles (Chelonia mydas ) have become more commonly observed along the west coast of the United States, particularly along the urban Southern California coast. Understanding the habitat use patterns and basic demographic rates of these turtles is important for resource management. To address these data gaps, we used spatial patterns created by natural geochemical cycling (i.e., marine isoscapes) to inform sea turtle movement and habitat use over time. This was done by analyzing stable isotope values of bone growth layers in turtle humeri and analyzing the values with age and size data obtained through skeletochronology. This approach allowed us to recreate the movements and foraging patterns of green sea turtles in Southern California. We present vital life-history and demographic data, including the oceanic stage duration, timing of ontogenetic habitat shifts, and multi-year foraging patterns. Sea turtles depart the oceanic habitat recruiting to neritic foraging grounds around 6.6 years of age, indicated by nitrogen isotope values (δ¹⁵N), but turtles may do so as early as one year old, or may remain in oceanic zones for much longer. Once settled into isotopically distinct coastal habitats, it was common for turtles to establish multi-year residency, and while many appeared to consume at least some seagrass, stable carbon isotope values (δ¹³C)—a primary indicator of critical habitat—suggested that it was not the primary diet item of most individuals. Collectively, these findings fill information gaps about green turtle life-history, which have immediate application to ongoing regional management efforts.

Harbour seals (Phoca vitulina) have a broad distribution in coastal ecosystems across the northern hemisphere. In southern Scandinavia, a lack of spatially-resolved data on harbour seal populations poses a major challenge for developing ecologically informed management frameworks, particularly in Norway, where populations are regulated using county-level administrative boundaries. In this study, we use haul-out data from 26 harbour seals tagged with GPS phone tags during the post-moult period to provide the first assessment of connectivity and movement across management boundaries in the Skagerrak–Kattegat region of southern Scandinavia. Specifically, we examined the frequency and timing of haul-out events relative to management units and quantified spatial networks of connectivity across national and sub-national jurisdictions. We reveal a high degree of spatial connectivity in the region, with haul-outs occurring over a broad, integrated network along the Skagerrak–Kattegat coastline. Generally, harbour seals in the region had a high probability of performing cross-boundary haul-out events, with individuals repeatedly transitioning across distinct Norwegian management units, as well as transnationally between Norway, Sweden and Denmark. This study offers critical insights into harbour seal movement ecology in this data-limited region, whilst also addressing an important topic of applied management. We demonstrate that the current management units in the Norwegian Skagerrak may not adequately reflect the spatiotemporal scales of harbour seal movement. Importantly, these findings can complement forthcoming genetic data and support efforts to redefine management units in the area. More broadly, our study illustrates how telemetry-based assessments of spatial connectivity can provide a powerful tool to inform management frameworks for other wide-ranging marine species facing similar conservation challenges.

Species interactions are fundamental to ecological and evolutionary processes, shaping ecosystem dynamics and driving biodiversity. Among those, interactions between flies and amphibians are common in tropical areas, yet most aspects of their ecology and evolution are understudied. Using the PRISMA method, we systematically review the literature to examine the direct and indirect threats imposed by Diptera flies attacking amphibians and the behavioral, physiological, and acoustic defenses they elicit. We delve, for instance, into the eavesdropping behavior of some dipteran species, which use anuran calls as cues for host-seeking, and the potential impacts on frog communication systems. As flies can be disease vectors, we investigate pathogen transmission to amphibians as an indirect cost imposed by flies attacking them and examine the role of species specificity in these dynamics. Finally, we address how human activities are currently impacting these long-established interactions between dipterans and amphibians. We focus on potential disruptions caused by habitat alteration, the presence of invasive species, and climate change. By synthesizing existing knowledge of the threats imposed by flies on amphibians, we shed light on these groups of growing conservation concern given their current escalating extinction rates. Ultimately, our findings provide valuable insights into the intricacies of species interactions and underscore the urgent need for comprehensive studies mitigating the adverse effects of anthropogenic disturbances on these clades.

Understanding the foraging ecology of endangered marine mammals provides important information for their conservation yet remains challenging due to the elusive, underwater nature of their feeding habits. Here, we used environmental DNA (eDNA) metabarcoding with two complementary 12S rRNA markers to characterize potential prey communities available to the critically endangered Rice's whale (Balaenoptera ricei) in its core habitat in the northeastern Gulf of America (formerly Gulf of Mexico). Water samples (N = 21) collected during a 2019 survey within Rice's whale feeding areas detected 99 unique fish species across 62 families, exceeding the diversity recorded by concurrent trawl surveys. The combined metabarcoding approach revealed 74 fish species not recorded in trawls, while 16 trawl-caught species went undetected by eDNA. Notably, eDNA yielded higher detection rates for several potential prey taxa previously identified through stable isotope analysis and trawl surveys, resulting in an updated list of top potential prey. These findings suggest that key prey species may be more prevalent in Rice's whale habitat than previously documented. To support these analyses, existing reference databases were expanded by sequencing the 12S rRNA gene from 15 regional fish species, using new primers developed for this study. Our study demonstrates the value of eDNA as a complementary tool for monitoring the prey community of this critically endangered cetacean, while highlighting the need for continued development of reference databases to maximize the ecological insights gained from marine metabarcoding applications.

Following catastrophic population declines in the 1980s and 2022, the keystone herbivore Diadema antillarum has become a focal species for Caribbean-wide restoration initiatives. In the present work, we combined an 11-month field survey across four reefs on the island of Culebra, Puerto Rico, with reciprocal transplants to evaluate physiological performance and DNA methylation responses of D. antillarum to seawater temperature, salinity, sedimentation, and nutrient gradients. Environmental parameters varied significantly across sites and seasons (GLM, p < 0.01). Urchin densities were negatively correlated with sedimentation, and righting response (a proxy for neuromuscular function) slowed under elevated sedimentation. Epigenetic analyses revealed extensive DNA methylation variation clustering by season rather than site. Righting response correlated significantly with DNA methylation patterns, suggesting a role of epigenetic regulation in physiological plasticity. Surviving transplanted urchins rapidly recovered normal righting behavior, indicating individual-level acclimatization despite ~50% transplant mortality primarily attributed to handling stress rather than environmental incompatibility. Collectively, our results suggest that restoration efforts should prioritize low-sedimentation sites (< 30 mg·cm⁻²·day⁻¹) while implementing refined handling protocols and preconditioning strategies to enhance transplant success and minimize procedural mortality in suboptimal environments.

Interactions in single-host–parasite systems provide a tractable framework for understanding the ecological mechanisms that maintain community stability; yet, the link between species' multidimensional niches and their functional roles within these networks remains underexplored. Here, we integrated network topology, multidimensional niche analysis, and functional group delineation to investigate the adaptive strategies and assembly rules of a 12-species flea community on Mongolian gerbils (Meriones unguiculatus). The host-flea network was characterized by a stable, nested structure and exhibited strong seasonal dynamics, with connectivity peaking in summer and modularity increasing in autumn. To understand the underlying mechanisms, we quantified the niche breadth of each species along four identified ecological gradients. Our analysis revealed that the community was organized along a steep hierarchy of generalization. Two hyper-generalist species (Nosopsyllus laeviceps kuzenkoui and Xenopsylla conformis conformis), characterized by near-maximal niche breadth and core network positions, dominated the community. A broad niche was a major determinant of a species' role, showing a significant positive association with a wider range of exploited hosts (Wilcoxon test: p = 0.03, effect size = 0.82). In contrast, specialist species, such as the extreme specialist (Ophthalmopsylla jettmari), were confined to the network's periphery and a narrow subset of ecological conditions. Clustering based on the multidimensional niche profiles identified four distinct functional groups, reflecting a clear hierarchy of ecological strategies. Overall, this study suggests that, within this seasonally dynamic system, a hierarchical niche structure, rather than complex trade-offs, is a primary organizing principle, providing a more nuanced understanding of stability in parasitic systems.

Biodiversity underpins ecosystem functioning, and higher diversity of taxa and traits often enhances efficiency. However, such relationships may vary, as intraspecific variation—including differences across ontogenetic stages—can modulate a taxon's contribution to ecosystem functioning. We conducted laboratory experiments to examine the effects of shredder identity, diversity, and ontogenetic stage on leaf litter decomposition and fine particulate organic matter (FPOM) production. Three caddisfly shredder taxa (Allogamus, Potamophylax, and Sericostoma) were collected in two different months and fed with highly decomposable alder (Alnus glutinosa) leaves individually and in shredder combinations during 1-week incubation periods. The experiments reflected distinct larval instars and were conducted with a time interval of 2 months. We hypothesized that decomposition and FPOM production would vary with taxon identity and ontogeny, with diversity enhancing processing rates. We further expected higher processing rates in younger larvae due to their greater metabolic demands. Results showed that both shredder identity and ontogenetic stage significantly affected decomposition, FPOM production, and particle size distribution. The largest taxon, Potamophylax, had the highest decomposition and FPOM production rates and produced the largest FPOM particles, while the smallest taxon, Allogamus, had the lowest rates and produced the smallest particles. Within taxa, younger and smaller larval stages exhibited higher rates than their older conspecifics. These results highlight the importance of shredder identity and ontogenetic stage in shaping both the magnitude and timing of key ecosystem processes.

Urbanisation impacts biodiversity in coastal ecosystems. Conservation management is needed to improve species persistence in such areas where populations have become small and fragmented. We conducted a population viability analysis to compare management scenarios for an isolated population of the threatened green and golden bell frog (Litoria aurea) in a peri-urban area of coastal south-east Australia. The breeding population occupies a single wetland that is hydrologically connected to an intermittently open lagoon. The lagoon is periodically drained to reduce flood risk to residential areas, influencing the reproductive output of the population. We combined estimates of population size, demographics, dispersal and genetic diversity to compare the relative probability of local extinction over a 25-year forecast window under four management scenarios: (1) lagoon draining at historic rates (status quo); (2) halving the incidence of lagoon draining; (3) creating new breeding habitat; and (4) supplementing the population. Our modelling predicted that the population had a 60% probability of extinction under the status quo scenario, while halving the frequency of lagoon draining or creating a new but hydrologically distinct wetland nearby reduced the probability of extinction to 6%. Predictions of population size at the end of the forecast period never reached zero when 10 adults were supplementing the population each year. Our analysis suggested that this L. aurea population will likely go extinct if the current frequency of lagoon draining continues. We believed the most cost-effective strategy to improve the persistence of the population over a 25-year management horizon is to reduce how often the lagoon is drained so that sufficient water remains in the wetland to support egg and tadpole survival. We highlighted that artificially manipulating the hydrology of coastal environments to reduce flood risk can compromise the persistence of hydrology-dependent species.

The changing patterns of taxonomic diversity (TD) and phylogenetic diversity (PD) during forest succession can provide a reference for optimizing forest ecosystem management. The widely distributed Pinus kesiya var. langbianensis forest (PKF) in subtropical Yunnan, China, has important ecological and economic values. However, little is known about species diversity patterns and driving factors during the pine forest succession. Adopting the “space-for-time-substitution” (SFTS) approach and on the basis of community data from different successional stages, we investigated the dynamics of TD and PD across PKF succession by integrating environmental and spatial variables. The results show that both TD and PD follow a cosine pattern during succession, peaking at mid- to late-successional stages, but with TD lagging behind PD. TD responds more rapidly to changes in dominant environmental factors than PD. Moreover, there is an asynchronous oscillation between taxonomic β diversity (TβD) and phylogenetic β diversity (PβD). TβD is consistently greater than PβD and increases monotonically throughout succession, whereas the PβD still fluctuates in a cosine pattern. TD and PD are equally important in maintaining community stability, and the community becomes increasingly homogeneous and stable. Notably, early and late successional stages are dominated by competitive exclusion, whereas environmental filtering prevailed at mid-succession. The mean temperature of the driest quarter (bio9) plays an environmental filtering role in the community composition at the ecological scale, and the precipitation of the coldest quarter (bio19) shapes the phylogenetic structure by influencing the regional species pool at the evolutionary scale. Neutral and deterministic processes jointly govern β diversity, but niche differentiation has an increasing domination, which supports the “successional continuum hypothesis”. Spatial effects must be explicitly considered in SFTS-based successional studies. The management should prioritize conserving mid-successional stages (peak diversity) and balancing environmental heterogeneity with dispersal limitation. Ecological-evolutionary assembly linkages should be considered in the pinewood sustainable utilization and management.

Arid mountain ecosystems are characterized by unique environmental stresses and high biodiversity. However, knowledge regarding the distribution patterns, multidimensional characteristics, and shaping forces of plant community β-diversity—especially under extreme environmental conditions—remains insufficient. In this study, we focused on the northern slope of the central Kunlun Mountains, an extremely arid region, and analyzed plant community survey data from 72 sites. By applying β-diversity partitioning and multiple regression analyses, we systematically identified the patterns of both taxonomic and phylogenetic β-diversity and their components and evaluated the relative importance of geographic, climatic, and topographic distances in shaping β-diversity. The results showed that species turnover is the primary force structuring both taxonomic and phylogenetic β-diversity, and that these diversity indices increase substantially with elevational differences. The combined influence of geographic, climatic, and topographic distances explained 46.4% of the variability in taxonomic β-diversity and 53.6% in phylogenetic β-diversity. Variance partitioning analysis showed that β-diversity patterns were shaped predominantly by climatic distance, while the contributions of geographic and topographic distances were limited. Among climatic variables, mean annual temperature emerged as the most influential determinant. This study not only deepens our understanding of biodiversity maintenance mechanisms under extreme environmental conditions but also provides important scientific evidence for the formulation of biodiversity conservation and management strategies in this region, particularly for optimizing the spatial layout of multiple small nature reserves under a turnover-dominated β-diversity pattern.