Temporary Wetlands Research Articles

Glyphosate-induced biochemical changes in female Cynopoecilus sp. inhabiting temporary wetlands

Glyphosate is Brazil’s most widely used pesticide, often applied to different crops that may be close to temporary wetlands. This pesticide poses a threat to populations of annual killifish that live in these locations. Few studies have explored the toxicodynamics of pesticides in annual killifish. Here females of Cynopoecilus sp. at different development stages (young-adult and senile) are exposed to Roundup Original DI® herbicide (65, 130 and 260 µg/L of acid equivalent of N-phosphomethyl glycine (glyphosate)) to analyze its impact on oxidative balance and lipoperoxidation, including superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), and SOD/CAT ratio, as well as markers of intermediary metabolism such as total proteins (TPs), glycogen, and uric acid (UA). Senile females showed increased CAT and glutathione S-transferase activities and a decreased SOD/CAT ratio. Total protein and UA values were increased. Two-way ANOVA demonstrated correlations between age and different exposure groups for lipoperoxidation, SOD, CAT, GST, TPs, and UA, especially in senile females. Although it is not considered a target species, Cynopoecilus sp. suffers harmful effects from the interaction with this herbicide even at environmentally relevant concentrations. This impact was observed in senile females, which may result in reduced life cycle and reproduction quality.

High Ammonium Addition Changes the Diversity and Structure of Bacterial Communities in Temperate Wetland Soils of Northeastern China.

The soil microbiome is an important component of wetland ecosystems and plays a pivotal role in nutrient cycling and climate regulation. Nitrogen (N) addition influences the soil's microbial diversity, composition, and function by affecting the soil's nutrient status. The change in soil bacterial diversity and composition in temperate wetland ecosystems in response to high ammonium nitrogen additions remains unclear. In this study, we used high-throughput sequencing technology to study the changes of soil bacterial diversity and community structure with increasing ammonium concentrations [CK (control, 0 kg ha-1 a-1), LN (low nitrogen addition, 40 kg ha-1 a-1), and HN (high nitrogen addition, 80 kg ha-1 a-1)] at a field experimental site in the Sanjiang Plain wetland, China. Our results showed that except for soil organic carbon (SOC), other soil physicochemical parameters, i.e., soil moisture content (SMC), dissolved organic nitrogen (DON), total nitrogen (TN), pH, ammonium nitrogen (NH4+), and dissolved organic carbon (DOC), changed significantly among three ammonium nitrogen addition concentrations (p < 0.05). Compared to CK, LN did not change soil bacterial α-diversity (p > 0.05), and HN only decreased the Shannon (p < 0.05) and did not change the Chao (p > 0.05) indices of soil bacterial community. Ammonium nitrogen addition did not significantly affect the soil's bacterial community structure based on non-metric multidimensional scaling (NMDS) and PERMANOVA (ADONIS) analyses. Acidobacteriota (24.96-31.11%), Proteobacteria (16.82-26.78%), Chloroflexi (10.34-18.09%), Verrucomicrobiota (5.23-11.56%), and Actinobacteriota (5.63-8.75%) were the most abundant bacterial phyla in the soils. Nitrogen addition changed the complexity and stability of the bacterial network. SMC, NO3-, and pH were the main drivers of the bacterial community structure. These findings indicate that enhanced atmospheric nitrogen addition may have an impact on bacterial communities in soil, and this study will allow us to better understand the response of the soil microbiome in wetland ecosystems in the framework of increasing nitrogen deposition.

Salinisation of arid temporary pools alters crustacean hatching success but not phenology dynamics

The widespread acceleration of freshwater salinisation due to human activities, such as pollution, resource extraction and urbanisation coupled with climate change, poses a significant threat to aquatic ecosystems. Limited work has been directed towards salinisation effects in temporary wetland systems. These systems are characterised by unique crustacean communities reliant on dormant egg production. We assessed salinisation effects on temporary wetland crustacean communities from semi–arid pans in the Khakhea–Bray Transboundary Aquifer region of South Africa using a laboratory–based approach. Sediment from pans containing crustacean resting eggs was exposed to water with varying salinities (0‒10 ppt), and emergent hatchlings were assessed over a 30–day hydroperiod. At salinities of 2.5 ppt and above, there were significant decreases in emergent taxa richness and abundance. Spinicaudata and Ostracoda were the most sensitive taxa to high salinities. Cladocera, Copepoda, Notostraca and Anostraca hatchlings had shallower decreases with salinity, but hatchability still fell rapidly. There was a limited effect on community hatching phenology dynamics from salinity, with all taxa showing reduced hatchability over time overall, with the exception of Cladocera which exhibited a clear unimodal response, peaking around 20 days post‒inundation. This suggests that the main impact of salinisation in these systems will be reductions in hatching success and hence reduced recruitment, leading to changes in predation pressures, food web structure and functioning of these ecosystems, with implications for associated ecosystem services.

New records of fairy shrimp (Anostraca, Branchinectidae) in temporary wetlands from Patagonia

New records of fairy shrimp (Anostraca, Branchinectidae) in temporary wetlands from Patagonia

Functional Response of Aquatic Macroinvertebrate Communities to Temporality in Tropical Temporary Ponds

Temporary or stationary wetlands (ponds) are bodies of shallow water that experience periodic droughts and an irregular flood cycle throughout the year. Although these wetlands are widely distributed in the Colombian territory, there have been few studies on their ecology. The aim of this research is to determine the effects of hydroperiod on the functional diversity of aquatic and semiaquatic macroinvertebrates in five temporary ponds in the department of Magdalena (Colombia). The samplings were performed during the hydroperiods of the filling and drying phases. Samples were collected from all the microhabitats present (sediment, littoral, and limnetic zones). Correlation analyses were performed between the traits and sites in the two hydroperiods, and a multidimensional and comparative analysis of functional diversity was performed, where indices of distance, richness, and functional dispersion were calculated in each hydroperiod. Statistical differences in functional replacement were found for only one of the ponds; however, the other ponds showed a similar trend. These results fit the functional turnover ecological hypothesis in that the response of the aquatic and semiaquatic macroinvertebrate communities was associated with the hydroperiod of the ponds based on the habitat “templet” theory.

Local environmental variables outperform spatial and land use pattern in the maintenance and assembly of phytoplankton communities in the wetland cluster

Phytoplankton is a crucial primary producer in wetland ecosystems and is highly sensitive to changes in water quality. It has long been considered one of the most important biological indicators for monitoring water pollution. However, our understanding of the various aspects of phytoplankton communities assembly and the factors driving them remains limited. In this study, we conducted collection and analysis of phytoplankton samples from a temperate wetland cluster encompassing both lake and marsh types under the backdrop of industrial pollution from the petroleum industry. Our aim was to investigate the influence of spatial factors, land use patterns, and local environmental variables on the taxonomic and functional structure of the phytoplankton community, utilizing structural equation modeling (SEM) and variation partitioning. Our results revealed that environmental filtering exerts a greater relative impact on shaping the taxonomic composition of phytoplankton compared to mass effects. Human activities, such as industrial and agricultural production, can lead to landscape modifications that increase water nutrient levels and consequently influence the community composition. Taxonomic beta diversity is determined by both mass effects and environmental filtering. In contrast, functional beta diversity responds more to local environmental gradients, while the land use pattern was not important for facets of beta diversity in the wetland cluster. These results validate the concordance and complementarity between functional and taxonomy-based biome structures, highlighting the significance of integrating multiple ecological drivers. The results of this study contribute to a deeper understanding of wetland community assembly and the processes of biogeography, and are of crucial significance for the biological monitoring and management of freshwater ecosystem environmental pollution.

Technological Advances to Rescue Temporary and Ephemeral Wetlands: Reducing Their Vulnerability, Making Them Visible

Mediterranean temporary ponds are a priority habitat according to the Natura 2000 network of the European Union, and complete inventories of these ecosystems are therefore needed. Their small size, short hydroperiod, or severe disturbance make these ponds undetectable by most remote sensing systems. Here we show, for the first time, that the distributed hydrologic model IBER+ detects ephemeral and even extinct wetlands by fully exploiting the available digital elevation model and resolving many microtopographic features at drainage basin scales of about 1000 km2. This paper aims to implement a methodology for siting flood-prone areas that can potentially host a temporary wetland, validating the results with historical orthophotos and existing wetlands inventories. Our model succeeds in dryland endorheic catchments of the Upper Guadalquivir Basin: it has detected 89% of the previously catalogued wetlands and found four new unknown wetlands. In addition, we have found that 24% of the detected wetlands have disappeared because of global change. Subsequently, environmental managers could use the proposed methodology to locate wetlands quickly and cheaply. Finding wetlands would help monitor their conservation and restore them if needed.

Persistent effects of historical sea levels on the population structure of a temporary wetland copepod

Abstract Temporary wetland ecosystems are common in arid and semi‐arid environments, and are inhabited by diverse invertebrate communities. Little is known about the dynamics of genetic connectivity in the geographically scattered populations of these wetland specialists. The current study investigated the spatial genetic structure and dispersal history of a recently described calanoid copepod, Lovenula raynerae, reported from temporary wetlands in the Eastern Cape province of South Africa. We tested whether the species represents a single, well‐connected population or comprises different regional genetic groups, some of which may be rare or endangered. Mitochondrial COI sequences were generated for 365 specimens from 46 temporary wetlands spread across the species' known distribution range. Isolation‐by‐distance and isolation‐by‐environment patterns of partitioning genetic variations across the landscape were evaluated. In addition, the presence of historical impediments to gene flow between contemporary populations was investigated using a combination of Monmonier's algorithm and Bayesian reconstruction of phylogeographical diffusion in continuous space. The wetland populations were highly structured across the landscape and could be assigned to six distinct evolutionary lineages, potentially representing some level of cryptic speciation. Two distinct phases were identified in the dispersal history of these lineages. Initially, dispersal only occurred inland of a postulated barrier, but eventually the barrier disappeared and the species extended its range by spreading into regions close to the coastline. Molecular dating shows that the barrier represents the upper limit of the coastline during the Pliocene, and that its crossing was facilitated by Pliocene sea regression in southern Africa. Our finding shows that complex demographic histories can be preserved in the mitochondrial DNA of temporary wetland crustaceans because of limited effective gene flow after initial colonisation events. This makes them an interesting study system to explore the long‐term effects of climate change on arid ecosystem communities.

Seasonality in the feeding ecology of Black-necked swans (Cygnus melancoryphus) in a temperate wetland of southern Chile

Seasonality in the feeding ecology of Black-necked swans (Cygnus melancoryphus) in a temperate wetland of southern Chile

Effects of temperature and heat waves on embryonic development of annual fishes from Neotropical wetlands: Implications for climate change scenarios

AbstractClimate change projections predict warmer temperatures and increased frequency of heat waves in many regions across the globe. These scenarios are expected to strongly impact temperature‐dependent life‐history traits of aquatic species, such as the embryonic stage of annual fishes inhabiting temporary freshwater wetlands. Here, we assessed the effects of different incubation temperatures (18, 24, 27 and 30°C) and exposure to heat waves (18–30°C for 6 h) on aspects of the embryonic development: mortality and trajectory (direct development or diapause entry) of two Neotropical species of annual fishes from high‐ (Austrolebias nubium) and low‐altitude (A. cyaneus) areas. Temperatures of 30°C resulted in 100% embryo mortality in both species, and development trajectory differed between species across temperatures. Embryo mortality in the high‐altitude species was higher at 27°C, while a higher number of embryos of the low‐altitude species entered diapause II at 18°C. Embryo mortality and development trajectory after exposure to heat waves were similar between species. In terms of implications for climate change scenarios, temperatures above 27°C seem critical for the embryo survival of both species studied, although they seem capable to endure short‐term events of heat waves. In summary, our results indicate that the persistence of populations of high‐altitude annual fish species may be subject to higher threat under warming scenarios, since embryos from this species were more sensitive to increasing temperatures than the low‐altitude species.

A wetland permanence classification tool to support prairie wetland conservation and policy implementation

AbstractWetland permanence, the duration and frequency that surface water is present, affects biological communities and whether wetlands are protected under legislation in some jurisdictions. Wetland drainage in the Prairie Pothole Region (PPR) has changed the distribution of wetlands because smaller and more temporary wetlands are more likely to be drained. This change in distribution affects biodiversity and other wetland ecosystem services. In Manitoba, Canada, wetlands are treated differently under the Water Rights Act based on permanence classification and can either be drained with a simplified registration (temporary and ephemeral wetlands), drained with a permit requiring mitigation (seasonal wetlands), or are protected from drainage (semipermanent and permanent wetlands). To facilitate implementing a conservation program targeting the most vulnerable wetlands, we built a classification model using LiDAR and Sentinel‐2 data (1312 training observations). Our random forest model had 73% accuracy on 563 test observations and is applicable across the agricultural region of southwestern Manitoba. We predicted the wetland permanence class of 365,499 wetlands and built an online tool to help practitioners implement a conservation program that pays producers to conserve temporary and ephemeral wetlands. Our approach is applicable elsewhere in the PPR and other regions with variation in wetland permanence.

An evaluation of the landscape structure and La Niña climatic anomalies associated with Japanese encephalitis virus outbreaks reported in Australian piggeries in 2022

The widespread activity of Japanese encephalitis virus (JEV) reported in previously unaffected regions of eastern and southern Australia in 2022 represents the most significant local arbovirus emergency in almost 50 years. Japanese encephalitis virus is transmitted by mosquitoes and maintained in wild ardeid birds and amplified in pigs, the latter of which suffer significant reproductive losses as a result of infection. The landscape epidemiology of JEV in mainland Australia is almost entirely unknown, particularly in the eastern and southern parts of the country where the virus has not been previously documented. Although other areas with endemic JEV circulation in the Indo-Pacific region have demonstrated the importance of wild waterbird-livestock interface in agricultural-wetland mosaics, no such investigation has yet determined the composition and configuration of pathogenic landscapes for Australia. Moreover, the recent emergence in Australia has followed substantial precipitation and temperature anomalies associated with the La Niña phase of the El Niño Southern Oscillation. This study investigated the landscape epidemiology of JEV outbreaks in Australian piggeries reported between January and April of 2022 to determine the influence of ardeid habitat suitability, hydrogeography, hydrology, land cover and La Niña-associated climate anomalies. Outbreaks of JEV in domestic pigs were associated with intermediate ardeid species richness, cultivated land and grassland fragmentation, waterway proximity, temporary wetlands, and hydrological flow accumulation. This study has identified the composition and configuration of landscape features that were associated with piggery outbreaks reported in 2022 in Australia. Although preliminary, these findings can inform actionable strategies for the development of new One Health JEV surveillance specific to the needs of Australia.

Some like it salty: Spatio‐temporal dynamics of salinity differentially affect anurans and caudates in coastal wetlands

Abstract Coastal wetlands are naturally subjected to salinity, which is expected to increase through global climate changes. Most species will be affected by these changes, leading to major consequences for community structure and ecosystem functioning. We investigated variation of salinity of temporary wetlands across spatial (1,000 m from the ocean) and temporal (across three breeding season) scales relevant to coastal biodiversity and used amphibians (six species, sampled across one breeding season) as a model to investigate the consequences of the spatio‐temporal variation of salinity in 24 ponds situated on the Atlantic coast of France. We show that salinity is a highly dynamic environmental variable that varies widely both across spatial and temporal scales. The spatio‐temporal dynamics of salinity are a critical factor structuring amphibian communities that affect the main amphibian phylogenetic groups (caudates vs. anurans) differently. Temporal variation in salinity disrupts the match between salinity selected by reproductive adults and those experienced later by their developing offspring, which negatively affect reproductive success. Future changes in coastal salinity are likely to affect the structure and functioning of these ecosystems, excluding salt‐intolerant species and eventually leading to less diverse communities of salt‐tolerant species.

Mechanism of bacterial communities regulating litter decomposition under climate warming in temperate wetlands

Plant litter decomposition plays a crucial role in the flow of nutrients and energy in ecosystems. However, the mechanism of bacterial communities regulating litter decomposition under climate warming in temperate wetlands remains largely unknown. The objective of this study was to determine the influences of temperature on decomposition and the bacterial regulatory mechanism under climate warming in temperate wetlands. In this study, we conducted a 1.5-year litter decomposition warming experiment using dominant plant species in the temperate lake wetlands of the North China Plain. Our results showed that the decomposition rate (K) had a significant positive correlation with temperature, and the non-additive effects of litter decomposition could be clearly observed in the mixtures of Phragmites australis and Typha angustata, especially under warming conditions. Among the three types of litter, Phragmites australis had the highest temperature sensitivity (2.75), which meant that it would be most affected by climate change in the future. The concentrations of C and N showed a significant positive correlation with the decomposition rate and were mainly driven by Proteobacteria and Firmicutes, while the concentration of lignin and the lignin:N ratio had a highly significant negative correlation with the decomposition rate and were mainly driven by Bacteroidota and Actinobacteriota. Furthermore, the bacterial cooccurrence network revealed that the abundance of Firmicutes and Desulfobacterota increased significantly, and positive edges accounted for 67.81% ~ 71.14% under warming conditions. The bacterial networks of litter decomposition were mainly composed of symbiotic relationships, and warming was helpful for improving the positive correlations and symbiotic relationships of bacterial flora and sped up the litter decomposition process. These results will be helpful to further understand the mechanism of bacterial communities regulating litter decomposition under climate warming in temperate wetland ecosystems.

Restoring functional forested peatlands by combining ditch-blocking and partial cutting: An amphibian perspective

Artificial drainage for forestry has caused major degradation of temperate peatland ecosystems. Partial restoration of those ecosystems is now widely considered, but feasible targets and effectiveness of restoration practices are not well established. In this study, we analyse a forested peatland restoration experiment in Estonia from a functional perspective of amphibian populations. In 2014–2020, we surveyed a before-after-control-impact experiment that combined two habitat manipulations: partial cuttings for restoring sparse tree canopy cover, and ditch blocking with soil filling to restore the water table. We monitored the responses in the aquatic habitats and breeding of brown frogs (moor frog Rana arvalis and common frog R. temporaria). Along with the expected habitat changes (ditch blocking quadrupled water depths and tree cutting reduced the shade), we found that ditch blocking restored the soil-type specific water acidity levels that the draining had homogenized. Partial ditch blocking reduced frog breeding activity in the first year, but it recovered and increased later on, specifically on sapric Histosols and supported by temporary wetlands, floods and pools created. However, the number of offspring did not clearly respond to the restoration and instead varied much among years. Our results indicate that, in drained forested wetlands: (i) near-natural aquatic habitats are a distinct restoration target and several years of post-restoration monitoring are needed to confirm the development of ecological integrity; (ii) increased breeding activity of amphibians may not result in improved recruitment; and thus, (iii) integrative wetland restoration techniques could benefit from an “amphibian perspective” of sustaining their whole life cycles and the food webs they support.

Reproductive Strategy of the Annual Fish Leptopanchax Opalescens (Rivulidae) and Trade-Off Between Egg Size and Maximum Body Length in Temporary Wetlands

Reproductive Strategy of the Annual Fish Leptopanchax Opalescens (Rivulidae) and Trade-Off Between Egg Size and Maximum Body Length in Temporary Wetlands

Invasive Species Change Plant Community Composition of Preserved Prairie Pothole Wetlands

Plant communities in North American prairie pothole wetlands vary depending on hydrology, salinity, and anthropogenic disturbance in and around the wetland. We assessed prairie pothole conditions on United States Fish and Wildlife Service fee-title lands in North Dakota and South Dakota to improve our understanding of current conditions and plant community composition. Species-level data were collected at 200 randomly chosen temporary and seasonal wetland sites located on native prairie remnants (n = 48) and previously cultivated lands that were reseeded into perennial grassland (n = 152). The majority of species surveyed appeared infrequently and were low in relative cover. The four most frequently observed species were introduced invasive species common to the Prairie Pothole Region of North America. Our results suggested relative cover of a few invasive species (i.e., Bromus inermis Leyss., Phalaris arundinacea L., and Typha ×glauca Godr. (pro sp.) [angustifolia or domingensis × latifolia]) affect patterns of plant community composition. Wetlands in native and reseeded grasslands possessed distinct plant community composition related to invasive species' relative cover. Invasive species continue to be prevalent throughout the region and pose a major threat to biological diversity, even in protected native prairie remnants. Despite efforts to convert past agricultural land into biologically diverse, productive ecosystems, invasive species continue to dominate these landscapes and are becoming prominent in prairie potholes located in native areas.

Correction: Sedimentary Organic Carbon and Nitrogen Sequestration Across a Vertical Gradient on a Temperate Wetland Seascape Including Salt Marshes, Seagrass Meadows and Rhizophytic Macroalgae Beds

Correction: Sedimentary Organic Carbon and Nitrogen Sequestration Across a Vertical Gradient on a Temperate Wetland Seascape Including Salt Marshes, Seagrass Meadows and Rhizophytic Macroalgae Beds

Predatory invertebrates indirectly impact leaf‐litter breakdown by different foragers in temporary wetlands

AbstractTemporary wetlands constitute a reservoir of fauna, many of which are endemic species well adapted to the typical dry–flooded cycle. The degradation of organic matter (both autochthonous and allochthonous) is an important process in temporary wetlands. Wetland animals like caddisfly and anuran larvae participate directly and indirectly in litter breakdown. Both groups also experience predation by invertebrates and vertebrates, which could alter the dynamics of litter breakdown. We used mesocosms to experimentally study the roles of caddisfly and tadpoles in leaf litter breakdown in the presence of a caged predator. We investigated how the presence of different types of forager (larvae of the caddisfly Verger vespersus and Batrachyla taeniata tadpoles) impacts leaf litter breakdown and also whether the presence of a caged belostomatid predator affected this process. Additionally, we investigated the behavioral response of B. taeniata tadpoles and V. vespersus larvae to predation risk cues from belostomatids previously fed on tadpoles or caddisflies. Our results indicated that only caddisfly larvae have a significant impact on litter breakdown. Predation risk did not influence the process, caddisfly larvae exposed to a caged predator reached the pupal stage more quickly than larvae that were not thus exposed, and tadpoles significantly reduced their activity in response to predation risk cues. None of the life‐history parameters of B. taeniata were affected by the predator, but tadpoles accelerated their development in warmer water. Our study is the first in South America to analyze the interactions between a common assemblage of tadpoles and caddisfly larvae and their impact on leaf litter breakdown when they experience predation risk. The model used here contributes to our understanding of ecosystem processes such as leaf litter breakdown and the impact of different biotic and abiotic variables when foragers co‐occur in the food webs of temporary aquatic systems.

Evaluating capabilities of machine learning algorithms for aquatic vegetation classification in temperate wetlands using multi-temporal Sentinel-2 data

Different perspectives use of machine learning (ML) algorithms have proven their performance depends on the quality of reference data. This is particularly true when targets are complex environments, such as wetlands, on which a vast majority of studies are site-specific and based on a single date. With this work, an extensive reference dataset of about 400,000 samples was collected, covering nine different sites and multiple seasons, to be considered representative of temperate wetland vegetation communities at continental scale. Starting from this dataset, the performance of selected ML classifiers was compared for detailed wetland vegetation type mapping, using spectral indices (SI) derived from multi-temporal composites of Sentinel-2 as input. Global and per-class accuracy metrics were computed based on four independent training and testing subsets, extracted from the overall dataset, and the impacts of input features variation in number and sites covered were assessed. Our results show a generally higher predictive power for ensemble methods, such as Random Forest (RF) and eXtreme Gradient Boosting (XGBoost), compared to standalone ones, with the notable exception of Support Vector Machine (SVM); the latter in fact, in the algorithm that scored the highest overall accuracy (0.977 ± 0.001) and F-score for all the target classes. Decreasing the number of input features generally resulted in classification accuracy losses, less marked for RF than for SVM, while site-specific algorithms training showed more stability of SVM, thus indicating SVM stronger transferability than RF and XGBoost.