Ecohydrology最新文献

Biodiversity studies have traditionally focused on species rank, yet recent research highlights the inadequacy of this approach alone. Instead, scientists emphasise taxonomic and functional surrogacy methods, such as indices of taxonomic distinctness and functional diversity, to grasp the relationships among species and their functional characteristics within ecosystems. Despite being a significant river in the Deccan Plateau region, understanding of the taxonomic distinctiveness and functional diversity of the fish community of the Bhima River basin remains elusive. Thus, we conducted this study to understand the relationship between these indices and environmental drivers affecting the fish community in the Bhima River basin. We studied taxonomic distinctness (Δ⁺), variation in taxonomic distinctness (λ⁺), functional dispersion (FDis), functional divergence (FDiv) and functional evenness (FEve) of the fish community. By correlation and regression analyses, we found a significant association between taxonomic distinctness and functional diversity indices. We also found that these indices are mainly influenced by annual temperature range, mean temperature diurnal range and precipitation of the dry season. We recommend conducting a comprehensive assessment of fish populations and studying the potential effects of climate change on fish diversity to improve understanding of their distribution in the Bhima River basin.

Sustainable groundwater management must account for the needs of groundwater dependent ecosystems. To understand the relationship of ecosystems and seasonal water use, we studied the stable isotope composition (δ¹⁸O and δ²H) of water in streamside trees in a semi-arid streamside environment (Livermore, California, USA). We sampled seven trees at two sites every other month from April 2024 through April 2025 for tree xylem stable water isotope signatures. These data were compared to potential source waters: precipitation, imported surface water, soil water and regional groundwaters. Large daily precipitation events were found to be isotopically similar to regional groundwater and were thus treated as one water source. A Bayesian mixing model using stable water isotopes was used to determine the ratios of these three potential source waters (small daily precipitation events, groundwater/large daily precipitation events and imported water) present in tree xylem water. On average, tree water sources include 32% imported water (SD = 9%), 35% small daily precipitation events (SD = 10%) and 33% groundwater (SD = 3%), with significant seasonal variation (t_{summer-winter} = 30.8, p < 0.01), particularly drawing more imported water (more than 55%) in the summer. While small daily precipitation events contribute only 10% of the total precipitation in our dataset, it represents a third of water used by trees. In addition, while these ecosystems are designated as groundwater dependent ecosystems, the trees use approximately one third imported water and even more during dry summer months. This approach provides water managers with a practical tool for quantifying ecosystem water needs, supporting data-driven decisions and regulatory compliance. While California's Sustainable Groundwater Management Act emphasizes supporting groundwater dependent ecosystems, it allows flexibility in demonstrating benefits. Our methodology provides a way to document that management actions (such as managed aquifer recharge with imported water) deliver measurable co-benefits to GDEs.

Floating vegetation islands (FVI) act as dynamic eco-hydraulic elements in both natural and engineered waterways, yet their interactions with flow, particularly those influenced by root canopy morphology, remain insufficiently understood. This study employs a computational fluid dynamic (CFD)–based approach to investigate how different FVI root structures affect channel hydrodynamics and turbulence characteristics. The model was first validated and then used for simulation purposes. Three configurations were examined: tall roots (Case A), short roots (Case B) and a combination of tall and short roots (Case C). High-resolution CFD simulations were conducted in a rectangular open channel to analyse flow velocity patterns, turbulence dynamics and bed shear responses around these FVI. The results reveal that vegetation morphology strongly governs flow behaviour and energy distribution. Case A produced substantial flow blockage, pronounced velocity gradients and extensive wake zones associated with heightened erosion potential. Case B induced moderate flow reduction and exhibited faster flow recovery, resulting in lower shear stress but limited flow attenuation. Case C demonstrated a balanced response, achieving moderate velocity reduction and more uniform turbulence distribution throughout the flow depth. Turbulence intensity and bed shear stress patterns also varied considerably among configurations: Case A concentrated turbulent kinetic energy and exhibited sharp stress gradients, Case B maintained more consistent profiles, and Case C displayed a spatially distributed turbulence field and intermediate stress variability, promoting stable sediment transport and ecological equilibrium. These findings underscore the pivotal role of vegetation (root canopy) arrangement in regulating flow resistance, sediment dynamics and ecological functionality, suggesting that strategically designed FVI can optimize erosion control, enhance habitat complexity and improve hydraulic performance in riverine and channelized systems.

Coastal wetlands are dynamic ecosystems where freshwater-saltwater interactions are governed by both hydrological and oceanic processes. However, climate change and human interventions such as lagoon breaching increasingly disrupt these interactions, posing challenges for ecosystem conservation. This study investigates the hydrogeological controls on water levels and salinity in a coastal freshwater wetland enclosed by Avoca Lagoon, an Intermittently Closed and Open Lake and Lagoon (ICOLL) in New South Wales, Australia. The wetland supports the endangered Green and Golden Bell Frog (GGBF, Litoria aurea), which requires low salinity for breeding. Using a multidisciplinary approach—combining groundwater and surface water monitoring, electrical resistivity tomography and lagoon bathymetry and salinity profiling—the study identifies strong hydraulic connectivity between the wetland and the lagoon, mediated by both lateral and vertical saltwater intrusion pathways. We identify four distinct hydrological stages of the lagoon that influence groundwater-surface water interactions within the wetland. Groundwater discharge plays a critical but often constrained buffering role, sustaining freshwater conditions while being limited by anthropogenic regulation of lagoon water levels. These findings highlight the narrow hydrological range supporting GGBF habitat and the vulnerability of the system to even minor water level fluctuations. They also underscore the need for adaptive management strategies—such as dynamic berm operation, managed aquifer recharge and protection of recharge zones—to balance flood mitigation with wetland conservation. This study advances understanding of groundwater-surface water interactions that underpin ecological resilience and demonstrates that groundwater connectivity must be integrated into ICOLL management frameworks to enhance preparedness for future climate variability and sea level rise.

Amid escalating climate extremes in the 21st century, the hydrological regulatory functions of forest ecosystems have become crucial for climate adaptation strategies. Sichuan Province, encompassing critical headwaters of the Yangtze and Yellow River basins, sustains 23.7 million hectares of forests with distinctive elevational gradients (500–7500 m). This study implements the Lund–Potsdam–Jena Dynamic Global Vegetation Model (LPJ-DGVM) coupled with multitemporal Geographic Information Systems analysis (2010–2022) to systematically evaluate forest hydrological services. Through terrain-adjusted hydrological modelling and spatial clustering techniques, we quantify water retention capacities (annual average 2850 ± 320 m³/ha) and humidity stabilization effects (relative humidity enhancement: 8.3%–15.7%) across four major forest types. Geographically weighted regression reveals significant spatial heterogeneity in soil moisture storage (18.5–33.8% vol) and evapotranspiration rates (2.2–3.6 mm/day), with 62% of variations explained by bioclimatic drivers (temperature-precipitation synergy, r = 0.68) and anthropogenic pressure indices (population and gross domestic product composite, r = 0.59). Our proposed optimization framework integrates three implementation phases: (1) priority conservation of 12 critical water-yield zones (identified through hydrological sensitivity analysis), (2) rehabilitation of 850 km riparian corridors connecting fragmented habitats and (3) systematic resource integration through multifunctional landscape design. Scenario projections estimate 16%–24% enhancement in hydrological regulation efficiency, demonstrating viable pathways to reconcile ecological security (water provision capacity +19%), economic viability (ecotourism potential +28%) and social equity (disaster risk reduction for 4.3 million residents).

Fluvial wetlands, such as floodplains, are particularly vulnerable to increasingly frequent extreme climatic events such as droughts because river flows are tightly coupled to atmospheric drivers such as precipitation. At the same time, these ecosystems can play a crucial role in supporting biodiversity resilience by providing refuge during regional droughts. The Paraná River Basin, the second largest in South America, has experienced unprecedented reductions in river flow since 2019. Here, we examine the effects of this multiyear hydrological and meteorological drought (2019–2024) on bird assemblages in the Paraná River floodplain. We compared two distinct hydrological contexts: a period with greater water availability in the floodplain (i.e., ‘wet’ period; 2011–2013) and another marked by drier and more recent conditions (i.e., ‘drought’ period; 2021–2024). Comparisons were based on point counts conducted at 60 sites along approximately 450 km. At each point, we also quantified habitat heterogeneity. Under drought conditions, regional and per-point species richness, total abundance and Simpson diversity increased markedly, with non–wetland-exclusive species showing the strongest response. Habitat heterogeneity also increased and was positively correlated with all bird metrics; however, drought effects remained significant after accounting for habitat variability. Beta-diversity analyses revealed reduced species turnover during drought, and indicator-species analysis identified 63 species associated exclusively with drought (22% wetland-exclusive; 78% nonexclusive). Overall, our results suggest that although river levels reached historical lows and assemblages became dominated by non–wetland-dependent species, the floodplain retained sufficient wetland refugia to sustain, and in some cases even enhance, populations of wetland-dependent species during the drought.