Search Results (256)

Landscape patterns serve as important drivers of macroinvertebrate biodiversity. However, the mechanisms through which landscape dynamics influence biodiversity across different elevation gradients in undammed rivers remain poorly understood. Here, this study investigated macroinvertebrate communities in the Chishui River, which represents the only undammed tributary maintaining a natural flow regime in the upper Yangtze River. We documented 97 macroinvertebrate taxa (3 phyla, 16 orders, and 57 families) with a mean density of 314.93 ind./m². NMDS and PERMANOVA analyses revealed significant spatial heterogeneity in macroinvertebrate community composition, but no overall seasonal variation. However, functional diversity indices (e.g., FRic) exhibited seasonal fluctuations across the river system. Furthermore, we assessed nine landscape metrics to capture heterogeneity, complexity, and fragmentation effects. Random forest modeling with nine predictors revealed that landscape heterogeneity primarily drove functional diversity in the upstream areas, whereas landscape fragmentation was the dominant factor in the downstream areas. Functional diversity, which reflects trait-based ecological roles, provides more direct insights into ecosystem processes than taxonomic diversity alone. Notably, the taxonomic diversity indices (Margalef richness, Shannon–Wiener diversity, Simpson diversity, and Pielou evenness index) showed no significant correlations with landscape metrics. These findings highlight the critical role of functional diversity in evaluating landscape-mediated ecological effects. For effective conservation, management strategies should prioritize reducing anthropogenic disturbances in downstream areas while preserving natural landscape heterogeneity. Full article

The Dongting Lake wetland is an important habitat for rodents. In order to understand the structural characteristics of rodent communities and the effect of groundwater level on them, this study explored the changes in rodent community structure in four different habitats (Carex, Reeds, Carex + Reeds, and Poplar) from 2003 to 2023. Meanwhile, the relationships between groundwater level, nutrient composition of Carex brevicuspis, and structural characteristics of rodent communities were analyzed. The results showed that the advantages of rodent species in the four different habitats are different, and the community structure of rodents has undergone significant changes in recent years. A significant correlation between groundwater level and the nutrient composition of C. brevicuspis was found. Further analysis shows a significant correlation between the nutritional components of C. brevicuspis and the population structure of rodents. Crude protein, total phosphorus, and dry matter were three key plant nutrient indicators that were significantly correlated with both capture rate and the community diversity index (p < 0.05). Total phosphorus and crude protein were significantly negatively correlated with capture rate and Simpson’s index (p < 0.05), but significantly positively correlated with Pielou’s index and Shannon–Wiener’s index (p < 0.05), while the dry matter was completely opposite. The research conclusions suggest that different habitats and groundwater levels affect different characteristics of rodent community structures, and that plant nutrients are likely to be the mediator. Full article

Primary forests harbor extraordinary biodiversity, but conversion from primary forests to secondary forests often leads to biodiversity loss and diminished ecosystem functioning. While much of the existing research has focused on plants and vertebrates, soil fauna—particularly Collembola—remain underexplored in this context. To address this gap, we conducted a comprehensive assessment of the Collembola diversity and community composition in primary and secondary forests across two regions in northeastern China. Among 5587 Collembola individuals, 69 morphospecies were identified. The Collembola abundance and Shannon–Wiener index were significantly higher in primary forests, although the species richness did not differ significantly between the forest types. In contrast, the community composition differed markedly, with several taxa found exclusively in primary forests. Notably, environmental factors exerted stronger influences on Collembola communities in primary forests, suggesting that these ecosystems may be more vulnerable to climate change and external disturbances. These findings demonstrate that primary forests play a crucial role in protecting soil fauna diversity and emphasize that future conservation efforts should focus on the strict protection of primary forests. Full article

Investigating altitudinal distribution patterns of species richness represents a fundamental research objective in biogeography and community ecology. Hainan Island has tropical rainforests ranging from sea level to >1800 m a.s.l., with various animal species, including reptiles such as geckos. Information on the altitudinal distribution patterns of animal diversity on Hainan Island is limited. Thus, from October 2020 to June 2023, we surveyed Gekkonidae species on Diaoluo Mountain and Jianfeng Ridge in the Hainan Tropical Rainforest National Park using a line transect method. The two study sites were divided into seven altitudinal zones at intervals of 150 m from 31 to 1080 m a.s.l. We tested correlations between abundance and species diversity indices and altitude. Five gecko species were identified. The endemic Gekko similignum mainly occurred at high-altitude areas on both mountains, whereas Hemidactylus frenatus occupied low-altitude areas. Gehyra mutilata had the lowest abundance among all species at all altitudes. Diaoluo Mountain exhibited a higher species diversity and abundance than Jianfeng Ridge. Geckos on Diaoluo Mountain were mainly distributed between 31 and 920 m a.s.l., presenting a bimodal distribution, with peaks appearing in altitudinal zones II (181–330 m a.s.l.) and VI (781–930 m a.s.l.). The gecko distribution on Jianfeng Ridge ranged from 31 to 948 m a.s.l., presenting a unimodal distribution, with a peak in altitudinal zone V (631–780 m a.s.l.). Full article

Anthropogenic disturbances significantly impact plant biodiversity in subtropical forests. While prior research has primarily concentrated on taxonomic diversity, other dimensions of biodiversity, such as phylogenetic and functional diversities, remain insufficiently explored. This study simultaneously investigated these three facets of plant diversity in subtropical forests with two distinct disturbance histories in eastern China, aiming to elucidate the effects of intermediate anthropogenic disturbances on biodiversity. Disturbed deciduous broadleaf forests exhibited markedly lower Pielou evenness index values compared to their conserved counterparts (p < 0.05). Disturbed evergreen broadleaf forests demonstrated significantly higher species richness, Shannon–Wiener index scores, and phylogenetic diversity relative to those found in conserved forests (p < 0.05). Furthermore, both disturbed deciduous broadleaf and mixed evergreen–deciduous broadleaf forests displayed significantly reduced functional richness and quadratic entropy coefficient values when compared with their conserved equivalents (p < 0.05). Forest type exerted a significant influence on all three dimensions of biodiversity (p < 0.05). In conclusion, intermediate anthropogenic disturbances have the potential to enhance both plant taxonomic and phylogenetic diversities while concurrently diminishing functional diversity within the subtropical forests of eastern China. The mechanisms driving responses in plant diversity to intermediate anthropogenic disturbances vary according to forest types. Full article

The stand structure of ancient tea tree (Camellia taliensis) communities is critical for maintaining their structural and functional stability. Therefore, this study employed backpack laser scanning (BLS) technology to extract individual tree parameters (diameter at breast height, tree height, relative coordinates, etc.) in seven sample plots (25 m × 25 m each) to analyze their spatial and non-spatial structure characteristics. Firstly, the accuracy of diameter at breast height (DBH) and tree height (TH) estimations using BLS resulted in a root mean square error (RMSE) of 4.247 cm and 2.736 m and a coefficient of determination (R²) of 0.948 and 0.614, respectively. Secondly, in this community, trees exhibited an aggregated spatial distribution (average uniform angle > 0.59), with small differences in DBH among adjacent trees (average dominance > 0.48) and a high proportion of adjacent trees belonging to different species (average mingling > 0.64). Ancient tea trees in the 5–15 cm diameter class face considerable competitive pressure, with values ranging from 14.28 to 179.03. Thirdly, this community exhibits rich species composition (more than 7 families, 8 genera, and 10 species, respectively), strong regeneration capacity (with an inverse J-shaped diameter distribution), uniform species distribution (Pielou evenness index > 0.71), and high species diversity (with a Shannon–Wiener diversity index ranging from 1.65 to 2.47 and a Simpson diversity index ranging from 0.71 to 0.91), and the ancient tea trees maintain a prominent dominant status and important value ranging from 19.36% to 49%. The results indicate that, under the current conditions, the structure and function of this community collectively exhibit relatively stable characteristics. BLS provides a powerful tool for the research and conservation of rare and endangered species. Full article

Gehu Lake in the lower reaches of the Taihu Lake Basin has experienced water quality degradation due to increasing human activities, pollutant discharge, and non-point source pollution, which requires ecosystem restoration. Currently, the community structure of aquatic organisms and their influencing environmental factors remain poorly understood. Thus, in this study, we conducted comprehensive fieldwork in June 2024 and analyzed the community structures of plankton (i.e., phytoplankton and zooplankton) and macroinvertebrates, and their influencing environmental factors in Gehu Lake and the inflowing river. The trophic level index (TLI) and biodiversity indices (Shannon–Wiener, Pielou, and Margalef) were utilized to assess water quality status. Pearson correlation analysis and redundancy analysis (RDA) were applied to identify key factors influencing plankton and macroinvertebrate community structures. The dominant phytoplankton species included Merismopedia tranquilla, Microcystis aeruginosa, Aphanizomenon flos-aquae, Aphanocapsa elachista, and Aulacoseira granulata. The dominant zooplankton species were mainly Brachionus diversicornis, Brachionus calyciflorus, and Asplanchna priodonta. The dominant macroinvertebrate species were Microchironomus tabarui and Chironomus flaviplumus. The findings suggest that Gehu Lake exhibited moderate pollution levels, while the diversity indices were significantly correlated with environmental factors. The Shannon–Wiener index of zooplankton displayed a markedly negative correlation with Chl-a (p < 0.05). The results from redundancy analysis showed that TP, TN, SD, COD_Mn, and Chl-a were key environmental factors shaping the aquatic community structure in the lake. Full article

Species and phylogenetic diversity play vital roles in sustaining the structure, function, and resilience of plant communities, particularly in tropical rainforests. However, the mechanisms according to which environmental filtering and competitive exclusion influence diversity across forest layers remain insufficiently understood. In this study, we investigated the species and phylogenetic diversity patterns in two representative tropical rainforest sites—Bawangling and Jianfengling—within Hainan Tropical Rainforest National Park, China, focusing on communities associated with the endangered species Hopea hainanensis. We employed a one-way ANOVA and Pearson’s correlation analyses to examine the distribution characteristics and interrelationships among diversity indices and used Mantel tests to assess the correlations with environmental variables. Our results revealed that the plant community in Jianfengling exhibited a significantly higher species richness at the family, genus, and species levels (a total of 288 plant species have been recorded, belonging to 82 families and 183 genera) compared to that in Bawangling (a total of 212 plant species, belonging to 75 families and 162 genera). H. hainanensis held the highest importance value in the middle tree layer across both sites (IV(BWL) = 12.44; IV(JFL) = 5.73), while dominant species varied notably among other forest layers, indicating strong habitat specificity. Diversity indices, including the Simpson index, the Shannon–Wiener index, and Pielou’s evenness, were significantly higher in the large shrub layer of Jianfengling, whereas Bawangling showed a relatively higher Shannon–Wiener index in the middle shrub layer. Phylogenetic diversity (PD) and the phylogenetic structure indices (NRI and NTI) displayed distinct vertical stratification patterns between sites. Furthermore, the PD in Bawangling’s large shrub layer was positively correlated with total phosphorus in the soil, while community evenness was influenced by soil organic carbon and total nitrogen. In Jianfengling, species richness was significantly associated with soil bulk density, altitude, and pH. These findings enhance our understanding of the ecological and evolutionary processes shaping biodiversity in tropical rainforests and highlight the importance of incorporating both species and phylogenetic metrics into the conservation strategies for endangered species such as Hopea hainanensis. Full article

Numerous studies have demonstrated that in residential areas of Western cities, both luxury and legacy effects significantly shape tree species diversity dynamics. However, the specific mechanisms driving these diversity patterns in China, where urbanization has progressed at an unprecedented pace, remain poorly understood. In this study we selected 20 residential settlements and 7 key socio-economic properties to investigate the change trend of tree diversity (2006–2021) and its socio-economic driving factors in Beijing. Our results demonstrate significant increases in total, native, and exotic tree species richness between 2006 and 2021 (p < 0.05), with average increases of 36%, 26%, and 55%, respectively. Total and exotic tree Shannon-Wiener indices, as well as exotic tree Simpson’s index, were also significantly higher in 2021 (p < 0.05). Housing prices was the dominant driver shaping total and exotic tree diversity, showing significant positive correlations with both metrics. In contrast, native tree diversity exhibited a strong positive association with neighborhood age. Our findings highlight two dominant mechanisms: legacy effect, where older neighborhoods preserve native diversity through historical planting practices, and luxury effect, where affluent communities drive exotic species proliferation through ornamental landscaping initiatives. These findings elucidate the dual dynamics of legacy conservation and luxury-driven cultivation in urban forest development, revealing how historical contingencies and contemporary socioeconomic forces jointly shape tree diversity patterns in urban ecosystems. Full article

To explore the characteristics of species diversity and phylogenetic diversity, as well as the dominant processes of community construction, in different forest types (deciduous broad-leaved forest, mixed coniferous and broad-leaved forest, and Chinese fir plantation) in subtropical regions, analyze the specific driving patterns of soil nutrients and other environmental factors on the formation of forest diversity in different forest types, and clarify the differences in response to environmental heterogeneity between natural forests and plantation forests. Based on 48 fixed monitoring plots of 50 m × 50 m in Shouchang Forest Farm, Jiande City, Zhejiang Province, woody plants with a diameter at breast height ≥5 cm were investigated. Species diversity indices (Margalef index, Shannon–Wiener index, Simpson index, and Pielou index), phylogenetic structure index (PD), and environmental factors were used to analyze the relationship between diversity characteristics and environmental factors through variance analysis, correlation analysis, and generalized linear models. Phylogenetic structural indices (NRI and NTI) were used, combined with a random zero model, to explore the mechanisms of community construction in different forest types. Research has found that (1) the deciduous broad-leaved forest had the highest species diversity (Margalef index of 4.121 ± 1.425) and phylogenetic diversity (PD index of 21.265 ± 7.796), significantly higher than the mixed coniferous and broad-leaved forest and the Chinese fir plantation (p < 0.05); (2) there is a significant positive correlation between species richness and phylogenetic diversity, with the best fit being AIC = 70.5636 and R² = 0.9419 in broad-leaved forests; however, the contribution of evenness is limited; (3) the specific effects of soil factors on different forest types: available phosphorus (AP) is negatively correlated with the diversity of deciduous broad-leaved forests (p < 0.05), total phosphorus (TP) promotes the diversity of coniferous and broad-leaved mixed forests, while the diversity of Chinese fir plantations is significantly negatively correlated with total nitrogen (TN); (4) the phylogenetic structure of three different forest types shows a divergent pattern in deciduous broad-leaved forests, indicating that competition and exclusion dominate the construction of deciduous broad-leaved forests; the aggregation mode of Chinese fir plantation indicates that environmental filtering dominates the construction of Chinese fir plantation; the mixed coniferous and broad-leaved forest is a transitional model, indicating that the mixed coniferous and broad-leaved forest is influenced by both stochastic processes and ecological niche processes. In different forest types in subtropical regions, the species and phylogenetic diversity of broad-leaved forests is significantly higher than in other forest types. The impact of soil nutrients on the diversity of different forest types varies, and the characteristics of community construction in different forest types are also different. This indicates the importance of protecting the original vegetation and provides a scientific basis for improving the ecological function of artificial forest ecosystems through structural adjustment. The research results have important practical guidance value for sustainable forest management and biodiversity conservation in the region. Full article

Desert plant communities play a vital role in sustaining the stability of arid ecosystems; however, they demonstrate limited resilience to environmental changes. A critical aspect of understanding community assembly mechanisms is determining whether soil texture heterogeneity affects vegetation diversity in arid deserts, especially under conditions of extreme water scarcity and restricted nutrient availability. This study systematically examined the relationships between plant diversity and soil physicochemical properties across four soil texture types—sand, sandy loam, loamy sand, and silty loam—by selecting four representative desert systems in the Hami region of Xinjiang, China. The objective was to elucidate the mechanisms through which soil texture may impact desert plant species diversity. The findings revealed that silty loam exhibited distinct characteristics in comparison to the other three sandy soil types. Despite its higher nutrient content, silty loam demonstrated the lowest vegetation diversity. The Shannon–Wiener index (H′), Simpson dominance index (C), Margalef richness index (D), and Pielou evenness index (Jsw) for silty loam were all lower compared to those for sand, sandy loam, and loamy sand. However, silty loam exhibited higher values in electrical conductivity (EC), urease activity (SUR), and nutrient content, including soil organic matter (SOM), ammonium nitrogen (NH⁴⁺-N), and available potassium (AK), than the other three soil textures. This study underscores the significant regulatory influence of soil texture on plant diversity in arid environments, offering new insights and practical foundations for the conservation and management of desert ecosystems. Full article

Long-term monitoring of small mammal communities provides critical insights into biodiversity conservation by detecting ecosystem degradation and quantifying anthropogenic impacts. Using 13 years (2005–2017) of standardized live-trapping data from the Diannan area, China, we analyzed 22 small mammal species to assess population dynamics and community restructuring through co-occurrence network analysis, species composition trends, and multi-index diversity evaluation (Shannon–Wiener, Margalef, Simpson, and Pielou). The research results showed that, except for the two dominant species, Eothenomys miletus and Apodemus chevrieri, whose populations showed an increasing trend during the survey period, the populations of all other species showed a decreasing trend, and some species even faced local extinction. The species diversity index significantly decreased, and the complexity of the co-occurrence network structure also appeared at the local level. We observed a decrease in the diversity of small mammals and the interactions between species. Pearson correlation and redundancy analysis (RDA) revealed that temperature, precipitation, and sunshine duration were the primary environmental drivers of the observed temporal variations in small mammal community structure. These results emphasize the necessity of further conservation efforts to protect local ecosystems and mitigate the negative impact of human activities on the environment. Full article

The present study analyzed the vegetation diversity in three forests located in southern Romania and assessed their degree of similarity. Data were collected using frame quadrat sampling and species taxonomic identification. The methodology included the calculation of ecological indices (Shannon–Wiener, equitability, maximum entropy, Menhinick, Margalef, McIntosh, Gleason, and Simpson) and statistical analysis using ANOVA and Duncan tests (p < 0.05). Similarity between forests was evaluated using the Jaccard and Dice/Sørensen coefficients. The results showed that biodiversity increases with area size, and the forest ecosystem in Vlădila exhibited the highest number of woody and herbaceous species. Although the forest ecosystem in Studinița had the greatest floristic diversity, according to the Shannon–Wiener index, it also showed higher equitability (0.911 compared to 0.673 in Vlădila) due to a more uniform species distribution. The forest ecosystem in Studinița acted as an intermediate zone between those in Grădinile and Vlădila. Variations in diversity among the three areas reflect ecological differences influenced by location-specific factors such as soil type, climatic conditions, and human interventions. This suggests that ecological conditions and the physical characteristics of forests significantly impact the number and types of species that can coexist within an ecosystem. Full article

Mayfly nymphs are reliable indicators of aquatic habitat quality, and whilst their presence and relative abundance are often used in bioassessment schemes, it is important to recognise that these attributes are affected by the sampling method employed. To test these effects, we sampled stream habitats for mayflies using two commonly used techniques in a standardised setup: aquatic sweep nets and manual collection from stones. These methods resulted in different success rates in detecting certain taxa depending on their biological traits (preferred microhabitat and locomotion type). Whilst species lists generally overlapped between the two methods, they yielded different values of total abundance, taxon richness, Shannon–Wiener’s diversity index, assemblage saprobic index, and general community structure. These results suggest that reliance on a single collection method is prone to yield only partial information for ecological assessments and emphasises the importance of employing a sampling technique that is appropriate for the study question and goals or combining more than one method. Based on these findings, we outline the scientific justifications for using each sampling method. Full article

Urban parks are an important component of public urban spaces, which directly impact the living experiences of residents and the urban image. High-quality urban parks are crucial for enhancing the well-being of residents. This study selected Fukuoka, Japan, as the study site. Five urban parks were chosen to evaluate landscape visual quality by using the Scenic Beauty Estimation (SBE) method. The Semantic Differential (SD) method was used to get sample subjective landscape features. Meanwhile, sample objective landscape features were obtained by using semantic segmentation techniques in deep learning and combined with spatial analysis to understand their distribution. A regression model was established, which used the SBE values as the dependent variable and subjective landscape features as the independent variables to analyze the relationship between urban park landscape visual quality and subjective landscape features. The regression analysis revealed that sense of layering, harmony, interestingness, sense of order, and vitality were the core factors influencing visual quality. All five features had a significant positive impact on landscape visual quality. The sense of order was the most influential factor, which would be the key to enhancing the landscape perception experience. Moreover, the XGBoost model and SHAP value from machine learning were used to reveal the nonlinear relationships and significant threshold effects between urban park visual quality and five objective landscape features: openness, greenness, enclosure, vegetation diversity, and Shannon–Wiener diversity index. This study showed that when openness exceeded 0.27, the positive effect was significant. The optimal threshold for the greenness was 0.38. Vegetation diversity and enclosure had to be below 0.82 and 0.58, respectively, to have a positive impact. Meanwhile, the positive influence of the Shannon–Wiener diversity index reached its maximum at a value of 1.37. This study not only establishes a systematic method for diagnosing landscape problems and evaluating landscape visual quality but also provides both theoretical support and practical guidance for urban park landscape optimization. Full article