Wetlands are among the most diverse and dynamic ecosystems on Earth. Meanwhile, they have experienced habitat loss and degradation worldwide, leading to biodiversity declines. As a primary driver of wetland loss and degradation, fragmentation can pose profound impacts on natural environmental regimes of floodplain wetlands. Here, we investigated the composition of macroinvertebrate assemblages in the Heihe Floodplain, Northwest China comparing wetlands with connection to rivers (i.e., riverine wetlands) and those isolated from rivers (i.e., lacustrine wetlands), with the wetland type used as a proxy for hydrological connectivity. We observed evident differences in species composition and community structure of macroinvertebrates between riverine and lacustrine wetlands. Three indicator species (Palaemon sp., Radix sp., Gyraulus sp.) were identified for lacustrine wetlands, whereas none were detected for riverine wetlands. Compared to lacustrine wetlands, riverine wetlands had significantly lower taxonomic and functional richness, but they had significantly higher mean local contributions to taxonomic and functional beta diversity, as well as more heterogeneous communities at regional scale. Our study highlights the need for a balanced wetland conservation strategy that protects lacustrine wetlands with high local diversity while also maintaining or restoring appropriate hydrological connectivity to promote regional biodiversity recovery and enhance ecosystem service functions. It also underscores the importance of incorporating functional traits and beta diversity into environmental monitoring and conservation planning to safeguard wetland biodiversity and associated ecosystem functions and services.
Fire is an important disturbance in many terrestrial ecosystems across the globe. A byproduct of fire is partially combusted organic matter, or pyrogenic carbon (PyC), which can be difficult for most microbes to decompose. Pyrophilic fungi are fungi that can break down and use PyC, survive through extreme heat, and/or have adaptations to rapidly colonize under postfire conditions. However, only a few fungal taxa have been characterized for their pyrophilic traits. Understanding the growth strategies and pyrophilic traits of fungi found in post-fire environments can help us understand mechanisms of ecosystem recovery from fire and their contributions to carbon cycling. Here, we characterized the pyrophilic traits of seven fungal isolates (Trichoderma and Mucor species) by testing their ability to grow on different carbon substrates (media containing PyC, sucrose, or water agar). Isolates were also incubated across a range of temperatures to determine if carbon source impacts thermotolerance and if the ability to catabolize PyC co-occurs with higher thermotolerance. We found that PyC-associated fungi exhibited a wide range of growth strategies, and many were able to grow on PyC. However, we found weak evidence for thermotolerance and growth on PyC as coordinated pyrophilic traits. Finally, we also found high intraspecific variation in growth strategies and weak tradeoffs along the fungal economics spectrum growth traits. These results were additionally supported by FT-IR analysis of substrates and fungal tissues, which showed different tissue chemistry based on substrate. Our results highlight the importance of intraspecific variation in carbon use ability and growth strategy as a key area of future research for pyrophilic fungi.
Rapid urbanization and land-use change are reshaping ecological spaces in urban agglomerations, underscoring the need to identify conservation and restoration priorities under alternative development pathways. Taking the Yangtze River Delta as a case study, this study integrates landscape ecological risk assessment, morphological spatial pattern analysis, and circuit theory to evaluate ecological security network responses under business-as-usual, urban development, and ecological protection scenarios for 2035. To better capture the spatial heterogeneity of ecological resistance, landscape ecological risk was incorporated into the composite resistance surface together with land use, elevation, and slope, allowing resistance values to reflect differences among areas of the same land-use type under different landscape configurations and disturbance conditions. Multi-period validation yielded overall accuracies of 0.87 and 0.90 and Kappa coefficients of 0.81 and 0.85 for the 2018 and 2020 land-use simulations, respectively. Built-up land expanded most strongly under the urban development scenario, increasing by 6, 866.91 km2, whereas the increase was limited to only 54.37 km2 under the ecological protection scenario. Ecological risk exhibited a persistent spatial gradient of higher risk in the northeast and lower risk in the southwest, with high-risk areas concentrated primarily in highly urbanized regions. Ecological pinch points and barrier points were mainly concentrated along urban fringes and intercity connection zones. Comparison of the three development scenarios showed that the ecological protection scenario was more effective in constraining uncontrolled urban expansion and maintaining ecological connectivity. However, barrier points inherited from historically developed areas persisted under the ecological protection scenario, and their number did not decline markedly. This trade-off indicates that ecological protection alone cannot fully resolve regional connectivity constraints. Improving regional ecological connectivity therefore requires targeted restoration of persistent barrier points together with coordinated protection of ecological source areas and corridors.
Rapid and unplanned urbanization significantly disrupts natural ecosystems and often leads to biotic homogenization across all climatic regions, including the tropics. The conservation potential of urban green spaces, including university campuses, remains relatively understudied, particularly regarding the divergent responses of different trophic groups within these ecosystems. University campuses are different from other urban environments in that their structures are primarily designed to support education and scientific research while conserving natural habitats. Here, we investigated the possibilities of taxonomic and functional homogenization within the tropical suburban environment of a university campus in Nadia, West Bengal, India, by studying the presence and functional characteristics of two phylogenetically distant arthropod groups, butterflies (primary consumers and pollinators) and spiders (top predators). Butterflies are often used as bioindicators, whereas spiders, which function as apex predators in urban ecosystems, serve to monitor habitat alterations. We performed systematic point counts for butterflies and visual searches for spiders across ten sampling plots categorized into three distinct habitat types based on anthropogenic disturbance (highly urbanized roadside, highly managed, and unmanaged natural zones). Taxonomic diversity was assessed using standard alpha diversity indices. Community composition and beta diversity were analyzed using Bray-Curtis dissimilarity, non-metric multidimensional scaling (NMDS), and permutational multivariate analysis of variance (PERMANOVA). To evaluate functional diversity (FRic, FEve, and FDiv), species were categorized according to key functional traits. We found high species richness at the suburban site, which remained consistent across all habitats. Our analysis showed a lack of significant community divergence, and functional diversity remained stable across different habitat categories in both groups (ANOVA: p > 0.05). Our results also indicated high functional redundancy for each land use. PERMANOVA test indicated that habitat type reflects a non-significant amount of variation in community composition for both butterflies (p = 0.413) and spiders (p = 0.886). These results demonstrate that different areas within a single university campus may not act as environmental filters for different species; instead, they support species assemblages based upon the available microhabitats. Overall, these findings highlight the importance of university campuses as functional refuges within urban biodiversity networks, emphasizing the need to maintain local botanical heterogeneity to conserve biodiversity.
Seasonal lake wetlands perform multiple ecological functions, including flood regulation, maintenance of land-water ecotonal habitats, and support for migratory waterbirds, and therefore play a critical role in regional biodiversity conservation. However, integrated assessments linking long-term wetland landscape reconfiguration, changes in habitat quality, and waterbird community responses remain scarce. Focusing on the Dongting Lake wetland, this study integrated land-use data, landscape metrics, habitat quality (HQ) and habitat degradation (DEG) estimated with InVEST, and waterbird species richness and community composition. Habitat-waterbird response models were developed using negative binomial generalized linear models and partial permutational multivariate analysis of variance. The results showed that the total wetland area increased from 5,019.03 km2 in 2000 to 5,118.04 km2 in 2020, whereas area of lake decreased by 533.87 km2 and reservoir/pond and marsh increased by 317.70 and 227.41 km2, respectively. For lake, percentage of landscape (PLAND) and largest patch index (LPI) both declined, indicating that wetland change was primarily characterized by internal class replacement and reconfiguration of dominant patches. Over the same period, mean HQ decreased from 0.47827 to 0.45371, whereas mean DEG increased from 0.17985 to 0.19445. Waterbird species richness showed generally weak associations with HQ, DEG, and landscape variables, although wetland LPI exhibited a positive but not significant trend during ER (IRR = 1.3763, FDR q = 0.0632). In contrast, community composition during ER was significantly associated with wetland LPI (semi-partial R2 = 0.1027, permutation p = 0.0078, FDR q = 0.0468). By jointly evaluating wetland landscape configuration, InVEST-based habitat quality, and waterbird response models, this study identified differences in habitat–waterbird associations between two recession periods. These findings provide an evidence base for adaptive management, ecological restoration of river-connected lake wetlands, and conservation of wintering waterbird habitats.
