Ecohydrology最新文献

Riparian corridors serve as critical ecohydrological interfaces that support biodiversity conservation, regulate ecosystem services and sustain agricultural productivity, particularly in regions facing intensifying climate stress. This study examines the ecological and socio-economic functions of riparian zones along the Indus River Basin, one of South Asia's most climate-vulnerable and agriculturally dependent regions. The research explores how shifts in hydrological regimes driven by glacial melt, erratic rainfall and prolonged drought impact plant species diversity, ecological integrity and food system resilience. Using a mixed-methods approach that integrates empirical field surveys, secondary data analysis and participatory assessments, the study identifies key stressors affecting riparian ecosystems and evaluates nature-based strategies for adaptation. Results highlight that the restoration of native vegetation, reestablishment of natural hydrological processes and incorporation of indigenous knowledge significantly enhance the adaptive capacity of riparian landscapes. These interventions not only improve ecological functionality such as water retention, soil stability and pollination but also contribute to the long-term viability of agricultural systems and local livelihoods. The research in question highlights the inevitability of active community involvement and participatory governance in the development and implementation of effective conservation efforts. The researchers suggest an inseparable linkage between ecological restoration and social resilience and policy coherence, which makes this integrated framework very likely to bring success in climate change-related food and water security through biodiversity preservation. In particular, the analysis points out protecting and rehabilitating riparian zones as an ecological imperative as well as a strategic measure to promote sustainable development and climate resilience among transboundary river systems, like the Indus.

Tree transpiration plays an important role in the hydrological cycle and largely determines the availability of watershed water resources. The Hanjiang River Basin is the source of the middle route of the south-to-north water diversion project; understanding the characteristics of tree transpiration in the basin and its key controlling factors is of great importance for sustainable water resources management of the region. In this study, we measured the sap flux density as a surrogate of transpiration for three representative tree species (oak, poplar and pine) from January 2021 to December 2023 in the Hanjiang River Basin. Results showed that incoming short-wave radiation (Rsi) and vapour pressure deficit (VPD) are the major factors controlling daytime sap flux density. The nighttime sap flux density generally correlates with the daytime sap flux density for all the tree species. A statistical model was developed for estimating daytime sap flux density based on Rsi and VPD, and the nighttime sap flux density is estimated using its dependence on daytime sap flux density. The proposed model could explain more than 85% of sap flux density variation of the three tree species. Soil water content (SWC) exhibited different impacts on sap flux density among the three tree species, with oak and pine showing clear SWC control, while poplar showed negligible SWC control. Incorporating SWC in the proposed statistical model improved the model performance for oak and pine during dry periods. This study revealed the characteristics of sap flux density of oak, pine and poplar in the Hanjiang River Basin and proposed a statistical sap flux density model for sap flux density simulations in the humid region of China.

With an increasing focus on ecological conservation, protecting and restoring spawning habitats for migratory species has become a focus of attention. However, restoration designs focusing only on increasing the quantity of spawning habitats for fish can result in little to no improvement, as the presence of various potential barriers would severely impede fish from accessing upstream habitats and utilizing their resources, thus further affecting the effectiveness of restoration efforts. Here, we suggest a more comprehensive assessment framework which closely links potential barriers and upstream migration opportunities with the quantity and quality of fish spawning habitats. This framework was implemented to assess the influence of potential migration barriers on the availability of spawning habitats in order to enhance the pertinence and effectiveness of river restoration technologies. In this study, we used the Heishui River, a primary tributary of the Jinsha River, as a case study to research the distribution of fish potential migration obstacles under hydropower development, and restoration efforts were designed to coordinate the accessibility and quality of spawning habitat, which was beneficial for increasing the restoration success probability. The results showed that neglecting river potential barriers would lead to overestimation of fish spawning habitat effectiveness. The effective spawning habitat (ESH) determined by considering potential barriers was reduced by 54.0%–86.9% (for Schizothorax wangchiachii) and 31.4%–86.9% (for Jinshaia sinensis) compared with the traditional weighted usable area (WUA) thus may lead to the deviation of ecological restoration patterns and effects. We highlight that, in the river ecological restoration targeting migratory species, priority should be given to potential barriers restoration close to the downstream estuary and those areas with poorer habitat quality, so as to ensure the effectiveness of more and better-quality spawning habitats. The proposed framework can help managers in conducting sustainable assessments and conservation of potential habitats while informing decisions on habitat restoration priorities.

Precipitation significantly alters the structure and stability of wetland vegetation ecosystems, particularly under increasing global climate change. Analysing the multi-scale mechanism and ecological effects of precipitation on wetland vegetation diversity patterns is crucial for wetland ecological restoration and biodiversity conservation. Based on the analysis of spatiotemporal heterogeneity and variation of the precipitation process, this paper constructed a high spatiotemporal resolution vegetation dynamic dataset of Poyang Lake by integrating multi-source remote sensing data and a machine learning method, and reveals the multi-scale influences and time lag effects of the precipitation process on the vegetation diversity pattern. The results showed as follows: (1) The spatial distribution of precipitation in Poyang Lake was unbalanced, and exhibited an overall increasing trend, with the precipitation intensity index showing non-stationary characteristics relatively. (2) From 2000 to 2020, vegetation diversity exhibited significant spatiotemporal heterogeneity. Increased vegetation landscape dominance was associated with a decrease in diversity and evenness indices, shifting the landscape distribution from balanced to unbalanced. (3) Vegetation diversity exhibited a notable lag in its response to precipitation, with the timing and magnitude of the response varying depending on the precipitation distribution and timescale. At the monthly scale, precipitation exhibited a negative correlation with Shannon diversity index (SHDI), Shannon evenness index (SHEI) and richness index (PT), but a positive correlation with Shannon dominance index (DI). The response intensity of the vegetation diversity pattern to precipitation followed the order: precipitation of month (PM), maximum 5-day precipitation amount (RX5day), and maximum 1-day precipitation amount (RX1day). The response of the vegetation diversity pattern to PM displayed both time-lag and cumulative effects. At the annual scale, annual total wet days precipitation (PRCPTOT) and precipitation frequency indices (R20, R25) significantly influenced the vegetation diversity pattern within the same year. The precipitation intensity index exerted a significant influence on the vegetation diversity pattern primarily with a 3–4 year lag. The influence of the precipitation process on the vegetation diversity pattern has a strong relationship with its instability characteristics. Our findings can offer valuable insights for the conservation and restoration of wetland vegetation diversity, and provide a scientific foundation for the sustainable management of the lake ecosystem.

Poyang Lake, with an obviously fluctuating water level, is connected to the Yangtze River by only one important waterway. To understand how water level fluctuation drives fish community diversity in this waterway, 12 indices across three dimensions (species diversity, taxonomic diversity and functional diversity) were calculated. Meanwhile, redundancy analysis (RDA) and generalized additive models (GAM) were used to evaluate the response of fish community diversity to water level fluctuations. We collected 63 fish species belonging to 7 orders, 13 families and 39 genera, with Cypriniformes being the dominant order. According to RDA, habitat changes driven by water level fluctuations were the primary factors underlying the shifts in fish community diversity. The GAM model further revealed that water level changes directly impacted the diversity of the fish community, leading to a decrease in the taxonomic distinctness index but an increase in species diversity, taxonomic diversity and functional diversity. Particularly, the number of species, the variation in the taxonomic distinctness index and the functional richness index exhibited highly significant correlations with water levels (p < 0.001). Therefore, high water levels were the primary and crucial factor in maintaining the fish community diversity in the waterway connecting Poyang Lake and the Yangtze River. These results could provide a scientific basis for the conservation and management of the fishery resources in the water body and provide important guidance to strengthen the protection and management of the lake ecosystem.

Extreme climate events such as floods and droughts become more often than before, but their ecological impacts on large lakes are still unclear. We studied responses of zooplankton species composition, density, biomass and diversity to an extreme flooding event by comparing zooplankton communities in a flooding year (2020) and a regular water level year (2021) in Poyang Lake, the largest freshwater lake in China. Mean density and biomass of zooplankton were not significantly different between the flooding and regular water level years. Density and biomass of rotifers were significantly lower in the flooding year than in the regular water level year, while the biomass of cladocerans was significantly higher in the flooding year. Species richness, Shannon–Wiener index, and Simpson index were significantly lower in the flooding year. A total of 45 and 60 species were detected in the flooding and regular water level years, respectively. Canonical correspondence analysis showed that water depth, alkalinity, transparency, conductivity, total nitrogen, nitrate, phosphate and turbidity were the main factors affecting the zooplankton community. This study provides evidence of flooding effects on zooplankton, which have implications for the conservation of freshwater lake ecosystems under extreme climate events.