Ecohydrology最新文献

Woody plant encroachment and subsequent thicketization is a global phenomenon that has been demonstrated to reduce groundwater recharge, yet it is unknown whether reducing woody plant cover will restore groundwater recharge rates to pre-encroachment levels. We investigated how savanna restoration influences soil moisture dynamics and deep drainage in the Post Oak Savanna ecoregion of Texas, USA, which overlies the recharge zone of the underlying Carrizo–Wilcox Aquifer. We compared soil moisture and deep drainage responses in water years 2023 and 2024 across the following three vegetation states: restored savanna, woodland mosaic and thicketized woodland. We found that savanna had higher profile mean volumetric water content than both woodland mosaic and thicketized woodland. Deep drainage rates were consistently higher in the savanna than in the woodland mosaic, and those in the intercanopy area were higher than those in the undercanopy areas. A water balance analysis provided independent validation of the matric potential based drainage estimates, demonstrating consistent temporal patterns and overlapping ranges. These findings indicate the effectiveness of thicketized savanna restoration in enhancing deep drainage and sustaining groundwater resources in subhumid landscapes.

Mosses and lichens that colonize rock barrens are critical for primary soil formation, landscape water storage and ecosystem succession. Mosses and lichens often grow as mats or cushions (referred to as mats) in and above depressions or crevices in the bedrock where moisture availability is greater. Shallow soil deposits covered with mats also provide critical nesting habitat for species-at-risk turtles in the eastern Georgian Bay, Ontario region. However, there is concern that a drying climate will reduce mat productivity due to a reduction in moisture availability, thereby impacting soil formation, landscape hydrology and their suitability as turtle nesting habitat. To better understand how drying may impact moss and lichen mats, we assessed the ecohydrological controls on moisture availability and productivity. Net primary productivity (NPP) was estimated using fine-scale surveys in 2014 and 2024 and complemented with measurements of mat moisture availability at the start and end of the 10-year study period. We found that mat catchment size had a significant impact on moisture availability, but the strength of the relationship was reduced during periods of low soil moisture availability. Catchment size did not have a significant impact on NPP, but there was slightly greater NPP in large catchments, and NPP increased with increasing bedrock depression storage. We suggest that under a changing climate, the overall productivity of moss-dominated rock barrens will decrease with decreasing moisture availability, the relationship between NPP and moss depth will strengthen and mat cover may shift towards more lichen-dominated rock barrens, influencing the availability and function of turtle nesting habitat.

Vegetated floodplains modulate river hydraulics through drag forces that affect flow conveyance, sediment transport and floodplain ecosystems. Non-uniform vegetation patches are widespread in natural floodplains and challenge drag prediction models, as the scale-dependent effects of patch configuration, canopy density and submergence remain inadequately quantified. Here, we directly measured drag forces on nature-like flexible woody vegetation across individual plant, isolated patch and reach-scale patch set-ups using a novel multi-scale drag measurement system in a recirculating flume. Investigations span emergent (H/h_d ≈ 1) and submerged (H/h_d ≈ 2) regimes, with patches varying in planform configuration and density. Results show that drag increased non-linearly with spatial scale. For instance, reach-scale patches having the same number of plants and canopy density (LAI) as the isolated ones exerted 1.1–2.2 times greater drag than isolated patches due to canopy continuity and wake interactions. Normalization of drag by one-sided leaf area revealed strong dependence on patch configuration and flow velocity, whereas normalization by newly defined configuration–density parameter (D_W) reduced inter-configuration variability, providing a scaling framework from emergent to submerged conditions. For patches submerged to twice the deflected canopy height, the total drag was reduced by roughly half compared with emergent condition. These findings show that vegetation-induced drag depends jointly on spatial scale, configuration, plant density and submergence. Overall, the results establish a physical basis for linking vegetation-induced drag to flow resistance and flow distribution, which together determine key ecohydrological functions such as flow partitioning, sediment retention and hydraulic connectivity across vegetated floodplains.

The increasing demand for freshwater, in combination with climate change and pollution, compromises the quality and quantity of water resources. These pressures have intensified cyanobacterial blooms, including toxic events that threaten human health and aquatic ecosystems. This study complements the objectives of the Water Framework Directive by addressing the current lack of systematic data on toxic cyanobacteria and cyanotoxins. Therefore, the occurrence of toxic cyanobacteria in Mediterranean reservoirs was revisited, and the findings were complemented by case studies of two Portuguese reservoirs. Phytoplankton community composition and toxin concentrations were analysed, and cyanobacterial strains were screened for toxin-producing genes. The data gathered from literature revealed widespread cyanobacterial blooms across Spain, Portugal and Italy, with cell densities frequently exceeding the WHO medium-risk threshold (20,000 cells/mL) and occasionally reaching the very high-risk level (1000,000 cells/mL). Microcystins were the most frequently detected toxins, often occurring above the WHO guideline (1 μg/L), whereas saxitoxin, anatoxin and cylindrospermopsin were detected less frequently. In Portugal, the Aguieira reservoir exhibited recurrent blooms and high phytoplankton biomass under eutrophic conditions, while the Rabagão reservoir showed no relevant cyanobacterial proliferation. Molecular analyses confirmed the presence of the mcyA gene in Microcystis aeruginosa isolated from Aguieira, indicating its potential for microcystin production, whereas Aphanizomenon flos-aquae lacked detectable toxin biosynthesis genes. Overall, these findings highlight the ecological variability of cyanobacteria in Mediterranean reservoirs and emphasize the importance of integrating toxin monitoring and molecular tools into water quality assessments to strengthen management strategies and safeguard public health.

Bartoň, D., M. Brabec, Z. Sajdlová, P. Blabolil, J. Kubečka, and M. Šmejkal. 2025. “ Cascade of Dams Amplifies Predation Risks for Rheophilic Fish Eggs.” Ecohydrology 18, no. 7: e70128. https://doi.org/10.1002/eco.70128.

In the first sentence in the “Funding” section, there is an error in one letter in the project code. The text “‘Assessment of biodiversity, population status, and management in non-salmonid fishing grounds’ (No. GL25020052)” is incorrect. This should be: “‘Assessment of biodiversity, population status, and management in non-salmonid fishing grounds’ (No. QL25020052)”.

We apologize for this error.

In semi-arid regions of the United States, mesquite trees are widely distributed across the landscape and play a pivotal ecological role, influencing hydrological processes and contributing to biodiversity. This is especially true in riparian areas, where understanding the adaptive water-use strategies of facultative phreatophytes is essential to understanding ecohydrology in this region and in similar dryland ecosystems worldwide. This study investigated the water-use strategies of mesquite trees (Prosopis velutina) located in the floodplain of the San Pedro River in southern Arizona, USA across two contrasting water years, a dry winter/wet summer (2022) versus a wet winter/dry summer (2023). We explored the impact of age, size and density of mesquite stands (characterized as mature trees, dense young thicket and thinned young thicket) to understand how these trees access both deep (groundwater) and shallow soil moisture (recent precipitation). Across stand types, trees opportunistically used both deep and shallow source water, a strategy that is consistent in woody plants that grow with a bimodal precipitation regime. That relatively young thickets show similar strategies to mature bosques demonstrates the potential for rapid restoration to bosque form and function. We also examined leaf water potential to assess seasonal water stress between the two water years and found that despite the summer precipitation in 2023 being 111% lower than in 2022, summer leaf water potential had similar dynamics. This unexpected result leads us to posit that the higher winter precipitation in 2023 compared to 2022 (91% higher) helped to buffer the trees in 2023 from water stress, even during a drier summer. This suggests that winter precipitation (deeper in the soil profile) remains an important water source for trees, even in dryland regions where surface water along riparian areas is readily available.

Characterizing the transit times or ‘ages’ of water through soil–plant systems is important for modelling ecohydrological processes and improving the accuracy of climate and terrestrial biosphere models (CTBMs). Soil–plant transit times, however, remain poorly characterized. Here, we revisit and leverage a unique isotope labelling dataset from a tropical mesocosm experiment to investigate soil–plant transit times over a 9-month period following a controlled drought. We propose a simple framework for modelling water movement through soil–plant systems, accessible to groups of researchers outside catchment hydrology. We employ two modelling approaches to estimating transit times—parametric (gamma/lognormal) and data-based (phenomenological). Our findings reveal that the parametric approach results in mean transit times (MTTs) that are generally longer than MTTs derived from the data-based approach, particularly in trees. Furthermore, our results demonstrate significant preferential flows in the vadose zone and similar water flow patterns via trees at the scale of this ecosystem. Analogous to preferential flow in soils, we refer to this ecosystem-scale water flow via trees as ‘xylem bias,’ whereby some trees have a stronger pull on water and/or larger pool of stored water than others. These results suggest a complex interplay of partitioning, storage and release mechanisms that remain largely unaccounted for in soil–plant transit time literature. We suggest that our findings have significant implications for CTBMs, underlining the need for improved representations of root water uptake and internal water storage. Our discussion illustrates how interdisciplinary approaches can enhance interpretation of tracer experiments and transit-time analyses.