Ecosystem Structure Research Articles (Page 1)

The structure and functioning of all ecosystems face growing threats, ranging from local development to global climate change. Ecosystems with little to no in situ primary production may be disproportionately dependent on resources from other ecosystems. We examined the role of basal resource availability on community structure and ecosystem multifunctionality of sandy beaches. We hypothesized that substantial marine macrophyte wrack inputs from productive nearshore ecosystems, like kelp forests, would drive recipient beach ecosystem structure and function. Using piecewise structural equation modeling, we found wrack abundance had a strong positive effect on beach food web diversity and biomass of detritivorous and predatory macroinvertebrates as well as ecosystem multifunctionality, an integrative measure of ecosystem functioning. Resource inputs and biodiversity both explained ecosystem multifunctionality, but the role of biodiversity was strongly underpinned by wrack inputs. The diversity and abundance of top predators, shorebirds, responded similarly to resource availability. Our findings suggest the influence of marine foundation species, such as giant kelp, can extend to recipient ecosystems as detrital subsidies. The highly coupled nature of these coastal ecosystems increases the likelihood that negative impacts to donor ecosystems will cascade to affect the structure and function of subsidized recipient ecosystems.

Abstract Background Climate change projections for western Patagonia, Argentina, predict a 1–3 °C increase in air temperature and a 10–30% reduction in precipitation by the end of this century, which will probably lead to more frequent and intense forest wildfires. Nothofagus are dominant tree species in Andean-Patagonian Forests ecoregion and are known to form symbiotic associations with ectomycorrhizal fungi (EcM). Forest fires threaten EcM, which play a critical role in ecosystem structure and functioning. In this study, we evaluated the impact of recent wildfires in Nothofagus forests on the taxonomic and functional diversity of soil fungi, with emphasis on EcM. Specifically, we aimed to identify fire-resistant fungal species that may contribute to forest restoration programs. To this end, we collected 151 composite soil samples from five paired burned and unburned (control) plots and assessed alpha and beta diversity responses to wildfires based on environmental DNA (eDNA) analysis. Results Soil fungi species richness was negatively affected by the interaction of wildfire with soil pH and nitrogen content. In contrast, Shannon’s index and Inverse Simpson’s index were positively influenced by wildfires, with calcium, phosphorus, and organic carbon of soil showing significant interactions. EcM species richness was negatively affected by wildfire, whereas diversity indices increased. In the soil fungal community, wildfire led to species turnover, whereas in the EcM community wildfire promoted a nestedness associated with species loss. Additionally, representative operational taxonomic units (OTUs), including Cortinarius sp. and Lyophyllum sp. were primarily associated with burned plots, suggesting their tolerance to wildfire disturbance. Conclusions In the fungal soil community, wildfire appeared to reduce species richness, while increased evenness, and species replacement. In contrast, the EcM community was largely lost, persisting as a reduced subset of pre-existing taxa. Active forest restoration through the inoculation of seedlings with native fire-tolerant EcM species could enhance tree establishment, growth, and survival in post-fire environments.

Spatial structure plays a vital role in forest operation, community dynamics, biodiversity conservation, and ecological functions, and it has been well documented at population, community, and regional levels. However, most studies on spatial structure focus on tree attributes without considering the relationships among neighbors. Based on the position, species, and size of neighboring trees, forest spatial structure can be classified into distribution, mixture, and differentiation classes. We analyzed the spatial patterns of these types in a 6-ha old-growth forest plot in southern China using pair correlation functions, mark correlation functions, and mark variogram functions. The results revealed that: (1) The distribution classes primarily exhibited aggregated patterns, with random associations dominating their relationships; (2) The mingling classes also exhibited aggregation, with spatial associations shifting from attraction to repulsion as the mingling degree increased; (3) The spatial structure of the differentiation classes was predominantly characterized by aggregation and random association. Intraspecific aggregation and small-tree aggregation were common features across all structural types. These findings are well explained by forest ecology theories such as dispersal limitation, mingling-size hypothesis, and the Janzen–Connell hypothesis, suggesting that different tree groups play distinct roles in forest communities. This study enhances our understanding of spatial structure in natural forest ecosystems and contributes to the monitoring, assessment, and management of forest resources.

Throughout geological time, an intertwined relationship between ecology and evolution has enabled distant clades to attain gigantism. By synthesizing fossil and modern data, we identify key tipping points in the rise of extreme-sized ocean animals—from early Cambrian arthropods and Ordovician mollusks to Triassic ichthyosaurs, Neogene sharks, and Quaternary whales. We show that ecological opportunities—from vacant niches to shifts in ocean productivity—have promoted the evolution of key adaptations to enhance prey intake, such as predatory appendages, specialized dentition, and baleens, ultimately enabling species to reach extreme sizes. The presence of ocean giants, in turn, has reshaped marine food webs, energy flow, nutrient cycling, and overall ecosystem structure. As such, their extinction or decline can have profound and lasting ecological consequences. Understanding the coevolutionary dynamics between marine giants and their environments is essential for predicting their resilience and conserving their critical roles in ocean ecosystems.

Climate change increases the recurrence of drought events with strong repercussions on grassland ecosystems. While the effects of single drought events on ecosystem structure and functioning are well understood, it is largely unknown whether and how recurrent drought events modify ecosystem responses to subsequent drought. Here, we assessed how the increase in drought recurrence of severe, annual summer drought impacted grassland communities. We examined these effects in a species‐rich sub‐alpine mountain meadow with drought recurrence of one, three and 13 years, compared to ambient conditions. We found that greater annual drought recurrence increased plant growth synchrony within the growing season. This pattern was associated with a reduction in species richness, a shift in plant functional groups, a loss of early‐seasonal plant species, and a constrained establishment of seedlings throughout the growing season. Furthermore, we show that negative drought effects were enhanced with an increasing drought recurrence, and that negative drought effects on plant communities outweighed the weak adaptive effects of individual species. We conclude that single drought and low‐recurrence drought studies may not adequately predict longer‐term plant community changes in our rapidly shifting climate. Furthermore, with the ongoing increase in drought recurrence, we predict grassland plant communities to become more vulnerable to future disturbances, as increasing seasonal synchrony reduces temporal buffering within the community, making the community less resilient. Moreover, given the weak adaptive effects of individual plant species to long‐term recurrent drought, we conclude that plant communities are unlikely to be able to adapt to the rapid increase in annually recurrent drought events.

Opposing δ13C and δ15N signatures in terrestrial and aquatic insects from Brazilian ecosystems by human disturbance.

Water level fluctuations shape phytoplankton community in the Xiangxi Bay from Three Gorges Reservoir.

Cultivated land-wetland complex increases humified DOM inputs and elevates eutrophication potential in Lake Lugu.

Pygoscelis penguins as indicators of perfluoroalkyl substances pollution and global health risks - case study from King George Island (Western Antarctic).

Environmental factors contribute to antimicrobial resistance, a global health threat. Contaminated gutter water in urban areas spreads resistant bacteria, disrupting ecosystems and promoting biofilm formation, causing widespread concern. This study aimed to evaluate antibiotic-resistant bacterial populations across six gutter ecosystems in Roorkee, Uttarakhand, India during summer against different classes of antibiotics, identify presence of beta-lactamase, and explores total bacterial communities, and predicting metabolic pathways through 16S rRNA based metagenomic approach of V3 region. The highest resistant bacterial population was found in HL_NS-6, and HL_NS-2, with highly resistance to Penicillin (ampicillin and oxacillin), Cephalosporin (Cephalothin), aminoglycoside (Kanamycin), fluoroquinolone (ciprofloxacin), and Antifolate (Trimethoprim) class antibiotics. Beta-lactamase activity was detected in all samples except HL_NS-5, indicated by nitrocefin hydrolysis. The microbial community in the six samples were composed with the major families enterobacteriaceae (15.4%) and pseudomonadaceae (8.29%), covering 23.7% of the total population. The highest taxa were found in HL_NS-2 and HL_NS-4, while the largest genera were Pseudomonas (8.3%), Escherichia (8.2%), Hydrogenophaga (6.85%), and Candidatus Moranella (5.4%). There were 21.25% common bacterial genera were present as core microbiome and rest were signified the population diversity among the six-gutter microbiome. The coexistence of common metabolic pathways (citric acid cycle, carbon, nitrogen metabolism etc.), and streptomycin, glycosphingolipid, lipopolysaccharide, cyanoamino acid metabolism pathways might be induced the development of antibiotic resistance in gutter microbiome. This study suggests the presence of antibiotic-resistant bacteria with antibiotic resistant metabolic pathways, and beta-lactamase genes in urban gutter water, which could be harmful to both human health and environmental ecosystems.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-20043-4.

Tyrannosaurus rex ranks among the most comprehensively studied extinct vertebrates1 and a model system for dinosaur paleobiology1. As one of the last surviving non-avian dinosaurs, Tyrannosaurus is a crucial datum for assessing terrestrial biodiversity, ecosystem structure, and biogeographic exchange immediately preceding the end-Cretaceous mass extinction -one of Earth's greatest biological catastrophes. Paleobiological studies of Tyrannosaurus, including ontogenetic niche partitioning2-4, feeding, locomotor biomechanics,5,6and life history7-9 have drawn upon an expanding skeletal sample comprising multiple hypothesized growth stages-and yet the Tyrannosaurus hypodigm remains controversial10-13. A key outstanding question relates to specimens considered to exemplify immature Tyrannosaurus1,14-19, which have been argued to represent the distinct taxon Nanotyrannus11,13,20,21. Here, we describe an exceptionally well-preserved, near somatically mature tyrannosaur skeleton (NCSM 40000) from the Hell Creek Formation that shares autapomorphies with the holotype specimen of N. lancensis. We couple comparative anatomy, longitudinal growth models, observations on ontogenetic character invariance, and a novel phylogenetic dataset to test the validity of Nanotyrannus, demonstrating conclusively that this taxon is distinguishable from Tyrannosaurus, sits outside Tyrannosauridae, and unexpectedly contains two species-N. lancensis and N. lethaeus, sp. nov. Our results prompt a re-evaluation of dozens of existing hypotheses based on currently indefensible ontogenetic trajectories. Finally, we document at least two co-occurring, ecomorphologically distinct genera in the Maastrichtian of North America, demonstrating that tyrannosauroid alpha diversity was thriving within one million years of the end-Cretaceous extinction.

ABSTRACTFunctional traits of plants and animals play a pivotal role in shaping mutualistic or predatory interactions within plant–animal systems, directly regulating the structure and function of forest ecosystems. Yet, the outcomes of multispecies interactions—particularly in seed–rodent systems—remain inadequately resolved, largely because traditional methods fail to track individual‐level interactions and seed fates with sufficient precision. To address this gap, we applied a novel double‐duplex passive integrated transponder (PIT) tagging technique to investigate the fates of seeds from four sympatric tree species (with distinct seed traits) when exploited by two sympatric rodent species (with contrasting body sizes) in a subtropical forest of Southwest China from 2018 to 2019. Our results revealed that rodent body size and seed size are key determinants of seed fates. The larger rat Niviventer confucianus scatter‐hoarded and consumed seeds of all four trees, with a significant preference for large‐sized seeds of Quercus variabilis and Lithocarpus harlandii. In contrast, the smaller mouse Apodemus draco did not hoard the large‐sized seeds of L. harlandii and showed a significant preference for small‐sized seeds of Camellia oleifera. Additionally, N. confucianus exhibited a higher interspecific pilfering rate on seeds of C. oleifera and L. harlandii than A. draco. Our study highlights the significant role of size traits in shaping the mutualistic or predatory interactions in seed–rodent systems and demonstrates the utility of individual‐based tracking in disentangling complex species interactions.

A key challenge for ecological science is to understand how biodiversity loss is changing ecosystem structure and function at scales that are relevant for policy1. Almost all biodiversity metrics are challenging to disaggregate into animal-mediated ecosystem functions such as pollination, seed and nutrient dispersal, and predation. Here we adopt an ecosystem energetics approach2 as a physically meaningful method of translating animal species composition into a suite of ecosystem functions. Drawing on new datasets that estimate biodiversity intactness and species population densities3-5, we quantify historical changes to energy flows through mammal- and bird-mediated ecosystem functions across sub-Saharan Africa. In total, trophic energy flows have decreased by more than one-third. The pattern of decreasing function varies by historical biome, driven by arboreal birds and primates in forests, terrestrial herbivores in grassy systems, and burrowing mammals in arid systems. Functions performed by megafauna in particular have collapsed outside protected areas. Compared with other biodiversity metrics, an energetics approach highlights the ecological importance of smaller animals and keystone species. The results can help practitioners conserve and restore functionally diverse, energetically intact ecosystems across land uses and biomes. By relating biodiversity intactness to energy and material flows, ecosystem energetics can also advance efforts to integrate animal-driven functions into biosphere and earth system models, helping us to understand possible regional or planetary boundaries6 for biodiversity.

Climate change and anthropogenic pressures increasingly threaten the ecological integrity of inland water bodies, particularly saline lakes due to their unique hydrological and biological features. This review focuses on Lake Tudakul, one of Uzbekistan’s largest saline lakes and a Ramsar-listed wetland, assessing its vulnerability under future climate scenarios. The study integrates climate scenario modeling (RCP4.5 and RCP8.5) with standardized ecotoxicological bioassays—Microtox®, MARA, algal growth inhibition, Lemna minor, and Daphnia magna toxicity tests—to evaluate combined effects of rising temperatures (2.0 °C and 4.5 °C) and chemical pollutants. Results reveal increased biological sensitivity to contaminants under elevated temperatures, suggesting potential synergistic impacts that may disrupt lake ecosystem structure and function. Lake Tudakul, a regional biodiversity hotspot, is exposed to agrochemical runoff, increasing salinity, and microplastic pollution, threatening aquatic organisms and ecological services. The accumulation and trophic transfer of pollutants—such as heavy metals, persistent organic compounds, and micro(nano)plastics—pose risks to food webs, public health, and water safety. These stressors may also increase the likelihood of harmful algal blooms and cyanotoxin outbreaks. The study emphasizes the urgent need for early-warning systems, adaptive management, and transboundary cooperation to mitigate ecological risks. Lake Tudakul exemplifies the vulnerability of semi-arid lakes under compounding climate and human pressures, highlighting the importance of integrative, ecosystem-based strategies to safeguard biodiversity and freshwater resources.

Abstract. Environmental gradients affect vegetation structure and ecosystem productivity. Along the northern Australia tropical transect (NATT), which transitions from tropical moist conditions in the north to arid conditions in the south, vegetation composition and structure are closely tied to rainfall patterns. We hypothesise that biotic competition and abiotic stress exhibit opposing patterns along the NATT rainfall gradient and aim to disentangle these effects on vegetation structure and productivity. Using a trait-based dynamic vegetation model, we simulated vegetation responses to varying competition and stress along the NATT. The model successfully simulated spatial variations and temporal patterns in carbon and water fluxes, where evapotranspiration and gross primary productivity decrease with rainfall along the gradient. Simulation results showed that taller and medium-sized Eucalyptus had higher carbon mass, leaf area index, and foliar projective cover at the wet end of the gradient. In contrast, Acacia and grasses were dominant at the dry end. Crown coverage shows spatial and temporal variability with rainfall, with higher variability in tree plant functional types (PFTs) crown cover in the north and more uniform in the south, while grasses have maximum coverage during the wet season in the dry end of the gradient. These patterns suggest a shift in the importance of biotic versus abiotic factors, with competition playing a more significant role in the wet region and stress becoming more influential as aridity increases in the south. Overall, our study underscores water availability as a primary driver of vegetation structure and highlights the role of competition and stress in modulating ecosystem structure, composition, and productivity along the rainfall gradient.

Abstract The Bering Sea is a highly productive subarctic ecosystem with some of the most valuable commercial fisheries in the United States. This seasonally ice‐covered sea has been rapidly changing due to ocean warming with impacts to the ecosystem structure and fisheries. The long‐term effects of these shifts on primary producers, however, are still unknown. Continuous monitoring of primary productivity in the Bering Sea is critical, yet observations that capture the ephemeral nature of plankton are challenging to sustain. To address this gap, high temporal resolution primary productivity rates were quantified at a mooring site (M2) in the southeastern Bering Sea in 2021. From a suite of sensors at M2 (fluorescence, dissolved oxygen, temperature, and total dissolved gas pressure), we calculated gross primary productivity (GPP), net primary productivity (NPP), and net community productivity (NCP), the latter based on net biological oxygen saturation using dissolved oxygen/nitrogen (O 2 /N 2 ) ratios. These estimates elucidate weekly patterns from the spring bloom through fall, when the water column becomes well‐mixed. In 2021, we observed average productivity during the spring bloom, yet wind patterns and mixing dynamics during the spring contributed to low productivity during summer and fall. The 2021 productivity metrics (GPP, NPP, and NCP) were compared across the growing season and contrasted with seasonal productivity estimates at M2 in previous years with consideration given to variability of ice conditions (warm/cold years) and wind stress.

As a distinct plant functional group, climbers critically sustain ecosystem structure and function globally. However, little is known about those in China. Here, we examine the diversity and distribution of Chinese climbers at a regional scale. First, climbing species data were collected. Then, Pearson correlations were conducted to assess relationships between environmental variables and climber species richness. Also, variation partitioning was used to reveal the pure and shared effects of four explanatory variable groups on species richness. A total of 3485 climber species (551 genera, 105 families) were recorded in China. Woody lianas dominated the climbing flora (64.73% of species) relative to herbaceous vines; twining represented the predominant mechanism (1829 species, 52.48%) relative to the others. Chinese climbers largely presented a pattern of species richness that decreased from south to north in China. Moreover, endemic and threatened climbers exhibited strong distributional congruence with all climbers. Additionally, four predictor groups (temperature, precipitation, geography, human impact) were found to jointly account for over 70% of species density variance across different climber types through variation partitioning, with precipitation’s pure effect dominating. Thus, Chinese climbers exhibit high diversity and an uneven distribution, primarily driven by precipitation. This study also provides a valuable reference on climbers at the regional scale for future studies.

The biodiversity-ecosystem function puzzle: Untangling the roles of topography, canopy cover, and structural diversity in Zagros woodlands.

Climate change-induced shifts in plant phenology have substantially impacted terrestrial ecosystem structure and function. While the effects of drought and heatwaves on leaf senescence have been studied, the response of leaf senescence to compound drought and heatwave events remains poorly understood, especially due to a lack of experimental evidence. In this study, we investigated the responses of leaf senescence to varying durations (13, 28, and 43 days) of compound drought and heatwave stress in saplings of three temperate deciduous tree species. We found that prolonged drought and heatwave conditions delayed leaf senescence by 20.2 in Koelreuteria paniculata and 22.4 days Hibiscus syriacus, respectively, potentially as a compensation for stress-induced reductions in growth. However, leaf senescence in the lowly tolerant Acer palmatum shifted from delayed to advanced, indicating a nonlinear response. Total photosynthesis, relative height increment, and basal diameter growth decreased in all three species, with the strongest reductions in Acer palmatum, followed by Hibiscus syriacus and Koelreuteria paniculata. Our findings demonstrate delayed effects of environmental stress on leaf senescence and highlight species-specific variation in response to compound drought-heatwave events, providing insights into how plants respond to climate change.

ABSTRACT The impacts of land‐use change on biodiversity may be studied through different approaches and biological scales, being abundance and morphological traits two trustworthy variables that can depict a cause‐and‐consequence scenario of environmental transformations at the population scale. In the tropics, native non‐forested ecosystems structure complex ecological communities, with species presenting complex responses toward environmental shifts. We investigated the effects of land‐use change on the abundance and morphological traits of dung beetle species in one of the major Neotropical wetlands, the Brazilian Pantanal. To achieve this, we sampled individuals of two widely distributed South American dung beetle species, Dichotomius bos and Dichotomius nisus , across native grasslands, exotic pastures, and soybean fields. We measured individuals' body mass, pronotum length/width ratio, relative protibial size, elytra length/width ratio, and size of pronotum relative to abdomen size—which are directly linked to ecosystem functions provided by dung beetles. Exotic pastures and soybean croplands had a higher abundance of dung beetles than native grasslands. Furthermore, soybean croplands had individuals with a lower pronotum length/width ratio than in native grasslands and exotic pastures for both species studied. Morphological traits in D. nisus were more strongly influenced by land‐use change than those in D. bos , indicating that even closely related species may respond differently to habitat alterations due to different ecological adaptations. Finally, these findings highlight that morphological traits are sensitive to land‐use changes in non‐forested ecosystems and could be important to complement the information obtained from studies that used community metrics.