Search Results (30)

A syntaxonomical revision of the plant communities of the Isoëto-Nanojuncetea class occurring in Sardinia is provided. Within this class, the ephemeral herbaceous hygrophilous associations linked to temporarily submerged surfaces occur, which are widespread in the European, Mediterranean, and Macaronesian countries. It groups plant communities floristically characterized by a rich set of annual hygrophytes or more rarely hemicryptophytes and geophytes, which are also physiognomically, ecologically, and structurally well differentiated. Within this class, two orders are recognized in Sardinia, such as Isoëtetalia and Nanocyperetalia, which are represented by several alliances. In particular, four alliances can be referred to as Isoëtetalia (Isoëtion, Menthion cervinae, Cicendio-Solenopsion laurentiae, and Agrostion pourretii), while a single alliance (Verbenion supinae) belonging to Nanocyperetalia has been identified. Within these alliances, several associations already described have been surveyed, while several other unpublished ones, are here proposed as new to science. Overall, 35 associations are recognized, 18 of which are described for the first time. Each higher-rank syntaxa and related associations are examined from a nomenclatural, floristic, ecological, and chorological point of view. In particular, the more significant phytosociological relevés regarding the examined associations were processed using cluster analysis, DCA ordination, optimclass diagram in order to highlight the correlations between them. As regards the floristic aspects, a checklist of the species occurring in the phytosociological relevés is provided. Full article

In this study, we selected a series of pothole wetlands to investigate their nucleation, evolution, and recent anthropogenic degradation in the Alcores Depression (AD), southern Iberian Peninsula, where over 100 closed watersheds containing shallow, ephemeral water bodies up to 2 hm² have been identified. We surveyed the regional geological framework, utilized digital elevation models (DEMs), orthophotos, and aerial images since 1956. Moreover, we analyzed precipitation and temperature data in Seville from 1900 to 2024, collected hydrometeorological data since 1990 and modelled the water level evolution from 2002 to 2025 in a representative pothole in the area. Our observations indicate a flooded surface reduction by more than 90% from the 1950s to 2025. Climatic data reveal an increase in annual mean temperatures since 1960 and a sharp decline in annual precipitation since 2000. The AD’s inception due to tectonic isolation during the Quaternary favoured the formation of pothole wetlands in the floodplain. The reduction in the hydroperiod and wetland degradation was primarily due to agricultural expansion since 1950, which followed an increase in groundwater extraction and altered the original topography. Recently, decreased precipitation has exponentially accelerated the degradation and even the complete disappearance of many potholes. This study underscores the fragility of small wetlands in the Mediterranean basin and the critical role of human management in their preservation. Restoring these ecosystems could be a highly effective nature-based solution, especially in semi-arid climates like southern Spain. These prairie potholes are crucial for enhancing groundwater recharge, which is vital for maintaining water availability in regions with limited precipitation. By facilitating rainwater infiltration into the aquifer, recharge potholes increase groundwater levels. Additionally, they capture and store run-off during heavy rainfall, reducing the risk of flooding and soil erosion. Beyond their hydrological functions, these wetlands provide habitats that support biodiversity and promote ecological resilience, reinforcing the need for their protection and recovery. Full article

This study evaluates the potential water availability in Barka Slough and the effects of changing hydrological conditions on the aquatic habitat of five protected species. Barka Slough is a historically perennial wetland at the downstream western end of the San Antonio Creek Valley watershed (SACVW). A previously published hydrologic model of the SACVW for 1948–2018 was extended to include 2019–2021 and then modified to simulate the future years of 2022–2051. Two models simulating the future years of 2022–2051 were constructed, each with different climate inputs: (1) a repeated historical climate and (2) a 2070-centered Drier Extreme Warming climate (2070 DEW). The model with the 2070 DEW climate had warmer temperatures and an increase in average annual precipitation driven by larger, albeit more infrequent, precipitation events than the model with the historical climate. Simulated groundwater pumpage resulted in cumulative groundwater storage depletion and groundwater-level decline in Barka Slough in both future models. The simulations indicate that Barka Slough may transition from a perennial to an ephemeral wetland. Streamflow, stream disconnection, and depth to groundwater are key habitat metrics for federally listed species in Barka Slough. Future seasonal conditions for each metric are more likely to affect federally listed species’ habitats under 2070 DEW climatic conditions. Future seasonal streamflow volume may negatively impact unarmored threespine stickleback (Gasterosteus aculeatus williamsoni) and tidewater goby (Eucyclogobis newberryi) habitats. Future seasonal stream disconnection may negatively impact the unarmored threespine stickleback habitat. Future groundwater-level decline may negatively impact Gambel’s watercress (Nasturtium gambelii) and La Graciosa thistle (Cirsium scariosum var. loncholepis) habitats and could influence the ability to use Barka Slough as a restoration or reintroduction site for these species. Results from this study can be used to inform water management decisions to sustain future groundwater availability in the SACVW. Full article

Plant growth, health, and resilience to stress are intricately linked to their associated microbiomes. Grapevine, functioning as a holobiont, forms essential relationships with fungi and bacteria across both its belowground (roots) and aboveground (leaves and berries) compartments. The root microbiome exhibits a stable, site-specific structure, whereas the microbiomes of ephemeral tissues such as leaves and berries, which regenerate annually, display more stochastic assembly patterns across growing seasons. Among these, grape berries represent a critical component in viticulture due to their direct influence on wine quality and flavor complexity. Berries provide a unique ecological niche, hosting diverse microbial communities composed of yeasts, bacteria, and fungi that interact with the grapevine and its surrounding environment. These microorganisms are not only pivotal to berry development but also contribute significantly to the synthesis of secondary metabolites and fermentation processes, ultimately shaping the sensory and organoleptic properties of wine. This review consolidates current knowledge on the grapevine microbiome, with a particular emphasis on the microbial dynamics of grape berries. Full article

Flood variability associated with urbanization, ecological change, and climatic change is of increasing economic and social concern in and around Flagstaff, Arizona, where flood hydrology is influenced by a biannual precipitation regime and the relatively unique geologic setting at the edge of the San Francisco Volcanic Field on the southern edge of the Colorado Plateau. There has been limited long-term gauging of the ephemeral channels draining the developed lands and dry coniferous forests of the region, resulting in a spaciotemporal gap in observation-based assessments of large-scale flooding patterns. We present new data from over 10 years of flood monitoring using a crest stage gauge network, combined with other channel monitoring records from multiple agency sources, to assess inter-decadal patterns of flood change in the area, with a specific emphasis on examining how various controls and disturbances have altered the character and seasonality of peak annual flows. Methods of analysis included the following: using Fisher’s Exact Test to compare the seasonality of flooding between historic data spanning the 1970s and contemporary data obtained since 2010; summarizing GIS-based spatial data and meteorological timeseries to characterize study catchment conditions and changes between flood study periods; and relating spatiotemporal patterns of flood seasonality and occurrences of notably large floods with catchment characteristics and environmental changes. Our results show systematic patterns and changes in Flagstaff-area flood regimes that relate to geologic and topographic controls of the varied catchment systems, and in response to records of climate variations and local catchment disturbances, including urbanization and, especially, high-severity wildfire. For most catchments there has been a shift from predominantly late winter to spring snowmelt floods, or mixed seasonal flood regimes, towards monsoon-dominated flooding, patterns which may relate to observed local warming and precipitation changes. Post-wildfire flooding has produced extreme flood discharges which have likely exceeded historical estimates of flood magnitude over decade-long monitoring periods by one to two orders of magnitude. We advocate for continued monitoring and the expansion of local stream gauge networks to enable seasonal, magnitude-frequency trend analyses, improved climate and environmental change attribution, and to better inform the many planned and ongoing flood mitigation projects being undertaken in the increasingly developed Flagstaff region. Full article

Anaxyrus microscaphus (The Arizona Toad) is an at-risk species that is endemic to the southwestern United States. Despite conservation concerns, little is known about the ecological drivers of its distribution and habitat use. We investigated the potential distribution of A. microscaphus at the range-wide scale and local scales (i.e., Zion National Park), using MaxEnt to model habitat suitability under current and future climate scenarios. Our models incorporated 12 environmental variables, including climatic, geomorphological, and remotely sensed data. The results showed good model accuracy, with temperature and elevation being the top contributing variables. Currently, 42.6% of the park’s area provides a suitable habitat for A. microscaphus, but projections for 2050 and 2070 indicate a significant reduction in suitable habitat across its range. Temperature was the most influential variable, with habitat suitability decreasing as the annual mean temperatures exceeded 10 °C. Precipitation, vegetation, and topography variables also significantly contributed to the models. The most suitable habitat within Zion National Park occurred along sloped rivers and streams and in valleys with sandy soils, emphasizing the importance of riparian habitat conservation for A. microscaphus survival and persistence. As climate change progresses, the species’ habitat is expected to become increasingly constrained across local and range-wide scales. Our models demonstrated a shift in the suitable habitat towards major river systems, indicating a potential reliance on larger permanent river systems as smaller, more ephemeral habitats decrease in size and abundance. Future management strategies should prioritize conserving and enhancing the resilience of these habitats. MaxEnt models can guide population survey efforts and facilitate the identification of priority conservation areas, saving time and resources for species of concern such as A. microscaphus. Further research, including field surveys and large-scale analyses, is necessary to further refine our understanding of this species’ distribution and how it may be impacted by climate and habitat change. Full article

International interest is growing in biodiversity conservation and sustainable use in drylands. Desert ecosystems across arid Central Asia are severely affected by global change. Understanding the changes in a plant community is an essential prerequisite to revealing the community assembly mechanism, vegetation conservation, and management. The knowledge of large-scale spatial variation in plant community structure in different Central Asian deserts is still limited. In this study, we selected the Taukum (TD, Kazakhstan) and the Gurbantunggut (GD, China) deserts as the research area, with similar latitudes despite being nearly 1000 km apart. Thirteen and 15 sampling plots were set up and thoroughly investigated. The differences in community structure depending on multiple plant attributes (individual level: plant height, canopy diameter, and plant volume, and community level: plant density, total cover, and total volume) were systematically studied. TD had a better overall environmental status than GD. A total of 113 species were found, with 68 and 74 in TD and GD, respectively. The number of species and plant attributes was unequally distributed across different families and functional groups between deserts. The values of several plant attributes, such as ephemerals, annuals, dicotyledons, and shrubs with assimilative branches in GD, were significantly lower than those in TD. The Motyka indices of six plant attributes (26.18–38.61%) were higher between the two deserts than the species similarity index (20.4%), indicating a more robust convergence for plant functional attributes. The community structures in the two deserts represented by different plant attribute matrices demonstrated irregular differentiation patterns in ordination diagrams. The most variance in community structure was attributed to soil and climatic factors, while geographic factors had the smallest proportion. Consequently, the community structures of the two distant deserts were both different and similar to an extent. This resulted from the long-term impacts of heterogeneous environments within the same region. Our knowledge is further deepened by understanding the variation in community structure in different deserts on a large spatial scale. This therefore provides valuable insights into conserving regional biodiversity in Central Asia. Full article

The determination of groundwater recharge (GWR) with an appropriate method is among the main subjects of groundwater resource management. This research is an event-scale quantitative assessment and a development of a water balance model of an aquifer response resulting from flash flooding and infiltration from the ephemeral streambed of some representative basins in Saudi Arabia. The methodology employed in the water balance analysis of this study starts with surface runoff rather than rainfall as in the literature, since the recharge process mainly occurs from runoff on the ground surface. A conceptual model of the local surface–subsurface interaction is developed to estimate the effective aquifer response (AR). The annual cumulative groundwater recharge (GWR) depths vary from 1.22 m to 6.97 m, with an average rise of 4.24 m at the studied wells; most of this happened following the May and April flash flood events. The results show also similar profile patterns and timings for most of the water level rises and falls. An average root mean square error (RMSE) of 0.46 m is obtained from the simulations and the coefficient of determination (R²) values range from 0.57 to 0.99. The results verified that the daily simulated groundwater elevations have shown very good agreement with the observed daily groundwater elevations over a time span of one year. In this work, the key issue to interpret the GWR depth from individual well samples is whether the model on the samples fits the measured groundwater level within the experimental runoff reaches (ERRs). The time steps (Δt) of the GWR simulation process are significantly affected by the high variability in the aquifer characteristics, as shown for the hydraulic conductivity values ranging from 5.3 m/day to 438 m/day within ERRs. This study highly recommends that groundwater recharge studies be site-specific. Otherwise, the extrapolation of the results even to adjacent basins is questionable. Full article

The wild vegetation of the Eastern Desert is characterized by openness and comprises perennials and ephemerals. The current study investigated the relationship between the edaphic factors of the natural vegetation along El Sheikh Fadl–Ras Gharib Road, Southwest Suez Gulf, in the northern sector of the Eastern Desert. The vegetation structure of the study area is relatively simple. The surveyed plants included 93 species from 22 families (51 perennials and 42 annuals). Asteraceae, Brassicaceae, Amaranthaceae, and Fabaceae were the richest families, constituting the majority of plant species (53.76%). Therophytes were the most frequent life forms. About 83.87% of the total flora were pluriregional elements of different affinities. Most of the recorded taxa occupied the Irano-Turanian/Mediterranean/Saharo-Sindian/Sudano-Zambezian chorotypes. The application of TWINSPAN classification resulted in grouping the vegetation into three main vegetation groups (A, B, and C), representing distinct microhabitats. The CCA ordination indicates diversity in vegetation group A. Group B was highly associated with Na, Mg, CaCO₃, silt, clay, and C/N. Group C showed a high correlation with sand, K, and N. The differences in wild plant life forms, richness, and diversity along the studied desert roadsides, in association with the soil differences, provide a good indication of plant biodiversity. Full article

Accurately mapping land use/land cover changes (LULCC) and forest disturbances provides valuable information for understanding the influence of anthropogenic activities on the environment at regional and global scales. Many approaches using satellite remote sensing data have been proposed for characterizing these long-term changes. However, a spatially and temporally consistent mapping of both LULCC and forest disturbances at medium spatial resolution is still limited despite their critical contributions to the carbon cycle. In this study, we examined the applicability of Landsat time series temporal segmentation and random forest classifiers to mapping LULCC and forest disturbances in Vietnam. We used the LandTrendr temporal segmentation algorithm to derive key features of land use/land cover transitions and forest disturbances from annual Landsat time series data. We developed separate random forest models for classifying land use/land cover and detecting forest disturbances at each segment and then derived LULCC and forest disturbances that coincided with each other during the period of 1988–2019. The results showed that both LULCC classification and forest disturbance detection achieved low accuracy in several classes (e.g., producer’s and user’s accuracies of 23.7% and 78.8%, respectively, for forest disturbance class); however, the level of accuracy was comparable to that of existing datasets using the same reference samples in the study area. We found relatively high confusion between several land use/land cover classes (e.g., grass/shrub, forest, and cropland) that can explain the lower overall accuracies of 67.6% and 68.4% in 1988 and 2019, respectively. The mapping of forest disturbances and LULCC suggested that most forest disturbances were followed by forest recovery, not by transitions to other land use/land cover classes. The landscape complexity and ephemeral forest disturbances contributed to the lower classification and detection accuracies in this study area. Nevertheless, temporal segmentation and derived features from LandTrendr were useful for the consistent mapping of LULCC and forest disturbances. We recommend that future studies focus on improving the accuracy of forest disturbance detection, especially in areas with subtle landscape changes, as well as land use/land cover classification in ambiguous and complex landscapes. Using more training samples and effective variables would potentially improve the classification and detection accuracies. Full article

Climate change and anthropogenic pressures are the main drivers of the quantitative and qualitative depletion of water bodies, worldwide. Nowadays, in many urban areas, discharging effluents from wastewater treatment plants (WWTPs) into surface water bodies is a management solution to face the problem of water scarcity and sustain environmental flows. Although this practice can cause some concerns in public opinion about possible ecological side-effects and impairment of quality on receiving streams, it is an important contribution to the environmental baseflow of ephemeral streams, but also to groundwater recharge, especially during dry seasons, and in semi-arid and arid regions. This latter occurs through losing reaches along the streambed, though many factors may affect the infiltration rate, such as spatial distribution of streambed sediments and bedrock or the presence of channel lining. Moving from such premises, this study focuses on the Canale Reale River, an effluent-fed stream located nearby the city of Brindisi on the south-eastern side of the Apulia Region, in Italy. The Canale Reale flows through the Torre Guaceto protected wetland, located along the Adriatic coast. It collects effluents from four WWTPs with wastewater contributing for about 16.5% of the annual volume of channel drainage (i.e., 3.82 Mm³ out of 23.02 Mm³ along its 50 km long course). Within the framework of a complex geological setting, the Canale Reale River crosses different lithologies, which implies different streambed infiltration conditions. Using the Reach Length Water Balance method (RLWB), the transmission losses between the watercourse and the underlying aquifers were investigated. Particularly, the method allowed for the estimation of a spatially-average value of the riverbed’s infiltration rate applicable to the whole river course as well as the minimum, average, and maximum potential transmission losses ($T{L}_P$) from the river to the underlying groundwater systems. Combining the estimated $T{L}_P$ values and the Flow Duration Curve (FDC) allowed for the inferring of the Transmission Loss Duration Curves (TLDC). Finally, the water volume infiltrating during an average hydrological year was estimated to be 6.25 Mm³, 61% of which was due to treated wastewater discharge. The results obtained confirm that the practice of increasing the river flow rates with WWTP effluents reduces the dry riverbed periods, with potential improvements to the river’s ecological sustainability and relevant enhancement of groundwater recharge. Full article

Different organ morphologies determine the manner in which plants acquire resources, and the proportion of biomass of each organ is a critical driving force for organs to function in the future. Regrettably, we still lack a comprehensive understanding of root traits and seedling biomass allocation. Accordingly, we investigated and collected the seedling root morphological traits and biomass allocation of 50 annual ephemeral species to clarify the adaptation to environment. The findings of this study showed that there was a significantly negative correlation between root tissue density (RTD) and root diameter (RD) (p < 0.05), which did not conform to the hypothesis of the one-dimensional root economics spectrum (RES). On this basis, we divided 50 plant species into those rooted in dense or gravelly sand (DGS) or loose sand (LS) groups according to two soil conditions to determine the differences in root strategy and plant strategy between the two groups of plants. Our study revealed that the species rooting DGS tend to adopt a high penetration root strategy. However, the species rooting LS adopt high resource acquisition efficiency. At the whole-plant level, 50 species of ephemerals were distributed along the resource acquisition and conservation axis. Species rooting DGS tend to adopt the conservation strategy of high stem biomass fraction and low resource acquisition efficiency, while species rooting LS tend to adopt the acquisition strategy of high root and leaf biomass fraction and high resource acquisition efficiency. The research results provide a theoretical basis for the restoration and protection of vegetation in desert areas. Full article

Snowpack loss in midlatitude mountains is ubiquitously projected by Earth system models, though the magnitudes, persistence, and time horizons of decline vary. Using daily downscaled hydroclimate and snow projections, we examine changes in snow seasonality across the U.S. Pacific Southwest region during a simulated severe 20-year dry spell in the 21st century (2051–2070) developed as part of the 4th California Climate Change Assessment to provide a “stress test” for water resources. Across California’s mountains, substantial declines (30–100% loss) in median peak annual snow water equivalent accompany changes in snow seasonality throughout the region compared to the historic period. We find that 80% of historic seasonal snowpacks transition to ephemeral conditions. Subsetting empirical-statistical wildfire projections for California by snow seasonality transition regions indicates a two-to-four-fold increase in the area burned, consistent with recent observations of high elevation wildfires following extended drought conditions. By analyzing six of the major California snow-fed river systems, we demonstrate snowpack reductions and seasonality transitions result in concomitant declines in annual runoff (47–58% of historical values). The negative impacts to statewide water supply reliability by the projected dry spell will likely be magnified by changes in snowpack seasonality and increased wildfire activity. Full article

Playas are ecologically and hydrologically important ephemeral wetlands found in arid and semi-arid regions of the world. Urbanization, changes in agricultural land use and irrigation practices, and climate change all threaten playas. While variations in playa inundation on the Great Plains of North America have been previously analyzed by satellite using annual and decadal time scales, no study to our knowledge has monitored the Great Plains playa inundation area using sub-monthly time scales. Thousands of playas smaller than ~50 m in diameter, which were not previously identified by the Landsat satellite platform, can now be captured by higher resolution satellite data. In this preliminary study, we demonstrate monitoring spatial and temporal changes in the playa water inundation area on sub-monthly times scales between September 2018 and February 2019 over a region in West Texas, USA, using 10 m spatial resolution imagery from the Sentinel-2A/B satellites. We also demonstrate the feasibility and potential benefits of using the Sentinel-2A/B satellite retrievals, in combination with precipitation and evaporation data, to monitor playas for environmental, ecological, groundwater recharge, and hydrological applications. Full article

Amphibian populations are threatened globally by stressors, including diminishing availability of suitable wetland breeding sites, altered hydroregimes driven by changing weather patterns, and exposure to contaminants. Ecological risk assessment should encompass spatial and temporal scales that capture influential ecological processes and demographic responses. Following the PopGUIDE framework of population model development for risk assessment, we used matrix population models, in conjunction with existing hydroregime predictions, under a climate change scenario to evaluate the effects of environmental stochasticity and aquatic pesticide exposure on amphibians that are dependent on ephemeral wetlands. Using southern toads (Anaxyrus terrestris) as an example, we simulated population dynamics with breeding success dependent on hydroregime suitability. Years were defined as optimal, marginal, or insufficient for successful toad recruitment, based on the duration of their potential breeding season and rate of larval development to metamorphosis. We simulated both probabilistic and chronologically specific population projections, including variable annual fecundity, based on hydroregime suitability and reduced larval survival from carbaryl exposure. In our simulations, populations were more negatively impacted by prolonged drought, and consequently multiple sequential years of reproductive failure, than by aquatic pesticide exposure. These results highlight the necessity of reliable climate projections to accurately represent the effects of altered hydroregimes on amphibian populations. Risk assessment approaches could be improved with flexible modifications that allow inclusion of various extrinsic stressors and identification of demographic and ecological vulnerabilities when precise data are lacking. Full article