Wetland Condition Research Articles

Evaluating the Land Use and Land Cover change of unprotected wetland situated in the Khultabad Tehsil of Aurangabad District, Maharashtra

The study investigated the effects of Land Use and Land Cover (LULC) change dynamics on the state and status of an unprotected wetland in semi-arid regions of India. The effects of the LULC shift on the wetland during a 15-year period were mapped and quantified using the long-term satellite image data collection. Using the supervised analysis approach, a multi-source satellite image analysis was carried out. The complete research area's Landsat data series were utilised to evaluate, map, and track LULC change over time. Wetland detection maps created for the 2007–2013–2016–2022 temporal periods were examined. According to the findings, the amount of agricultural land remained essentially constant during the comparative period, ranging from 29.71% to 31.43%. The percentage of waste land progressively grew from 14.29% to 22.86% between 2007 and 2016. By 2022, the plantation area will have shrunk from 15.43% in 2007 to 5%. Similarly, it is anticipated that the habitat would grow from 8.07% in 2007 to 12.93% in 2022. Farmland and fallow area figures are different because both land uses were determined using different season satellite pictures. But there is no obvious increase or decrease in the total agricultural area. These results may be used to create specialised wetland management plans and perhaps even a framework for restoring wetlands that are not currently under protection

Monitoring long-term vegetation condition dynamics in persistent semi-arid wetland communities using time series of Landsat data

Wetlands in arid and semi-arid regions are characterized by dry- and wet-phase vegetation expression which responds to variable water resources. Monitoring condition trends in these wetlands is challenging because transitions may be rapid and short-lived, and identification of meaningful condition change requires longitudinal study. Remotely-sensed data provide cost effective, multi-decadal information with sufficient temporal and spatial scale to explore wetland condition. In this study, we used a time series of Enhanced Vegetation Index (EVI) derived from 34 years (1988–2021) of Landsat imagery, to investigate the long-term condition dynamics of six broad vegetation groups (communities) in a large floodplain wetland system, the Macquarie Marshes in Australia. These communities were persistently mapped as River Red Gum wetland, Black Box/Coolibah woodland, Lignum shrubland, Semi-permanent wetland, Terrestrial grassland and Terrestrial woodland. We used generalized additive models (GAM) to explore the response of vegetation to seasonality, river flow and climatic conditions. We found that EVI was a useful metric to monitor both wetland condition and response to climatic and hydrological drivers. Wetland communities were particularly responsive to river flow and seasonality, while terrestrial communities were responsive to climate and seasonality. Our results indicate asymptotic condition responses, and therefore evidence of hydrological thresholds, by some wetland communities to river flows. We did not observe a long-term trend of declining condition although an apparent increase in condition variability towards the end of the time series requires continued monitoring. Our remotely-sensed, landscape-scale monitoring approach merits further ground validation. We discuss how it can be used to provide a management tool which continuously assesses short and long-term wetland condition and informs conservation decisions about water management for environmental flows.

The relationship between mountain wetland health and water quality: A case study of the upper Hanjiang River Basin, China

This study investigates the degradation process of mountain wetlands in the upper Hanjiang River Basin (HRB) over a 30-year span from 1990 to 2020. In particular, the landscape development intensity (LDI) index was employed to conduct a comprehensive assessment of the wetland health. This was subsequently combined with the spatio-temporal changes of water quality in the basin to explore the potential correlations between the health status of mountain wetlands and the associated watershed water quality. The results show that over the past three decades, wetland ecosystems have shrunk by 18% due to conversion into farmland, grass, construction land and forest land. This was significant between 2010 and 2020, as shown by a land use dynamic index of −1.121% during 2010–2020, which was significantly higher than that in the preceding two decades (0.003%, 0.367%) (p < 0.05). LDI values for individual sub-watersheds across different years ranged from 2.39 to 4.93, demonstrating an increasing trend since 2010. This indicates a heightened level of human interference in mountain wetlands. Although the water quality within the basin generally adhered to the Class II surface water quality standard, total nitrogen (TN) (primarily from farming) was a concern. Areas with relatively more human activity were observed to exhibit increased pollution levels, as demonstrated by a positive correlation between LDI and the concentrations of total phosphorus (TP), ammonium nitrogen (NH4+-N), and chemical oxygen demand (COD) in the basin. The LDI of the mountain wetland exhibited a consistent positive correlation with the water quality comprehensive function, both during the flood (r = 0.77–0.81) and non-flood (r = 0.61–0.70) seasons (p < 0.05). This indicates the significant impact of the wetland landscape structure on the water quality within a 1000 m radius on either side of the river. Special attention should be paid to the management and allocation of wetland landscapes within this 1000 m buffer zone. Furthermore, efforts to control upstream pollutant emission should be strengthened.

Impact of Artisanal Gold Mining on Wetland Health in Buhweju District, Southwestern Uganda

Wetland degradation due to anthropogenic activities including artisanal gold mining is widely common in Uganda, and this affects vegetation health status if not controlled. However, the use of the Normalised Difference Vegetation Index (NDVI) to determine the health status of wetlands is rare. In this study, remote sensing techniques with the use of spatial-temporal Normalised Difference Vegetation Index (NDVI) were used for the wetlands in Bitsya Subcounty, Buhweju district (noted for artisanal gold mining with the use of mercury) to determine the wetland health status for the period between 2012-2021. This was for the purposes of identifying target areas for intervention and developing appropriate, location-specific intervention options. 7 images of 30 * 30 m and 3 images of 10 * 10 m respectively, ortho-rectified, cloud-free Landsat and Sentinel images obtained from the USGS archive were analysed. The results showed that the high NDVI value (0.775) was detected in the year 2019 and the low NDVI value (0.068) was detected in the year 2017. The NDVI maps showed low values mostly in the middle of the wetland where artisanal gold mining was mostly taking place, indicating a huge decline in the wetland health status as compared to other wetland edges noticed with high NDVI. The results from the study suggest that the wetland policies in the study area could not be effectively implemented and this reduces the vegetation health status, threatening the functionality of the wetland and as well as loss of the free natural goods and services derived from them. This necessitates the development of wetland restoration campaigns. However, failure to implement the wetland policies may have an ecosystem impact on the wetland micro and macro-organisms, soil nutrients, and water quality as well as a decline in vegetation health

Fabrication and Field Performance of Power Weeder for Mechanized Rice Cultivation in Bangladesh

A study was aimed at modifying and manufacturing a power weeder at the local workshop using locally available material and evaluating its performance in the condition of Bangladesh. The Bangladesh Rice Research Institute's Farm Machinery and Post-harvest Technology (FMPHT) division (BRRI) took the initiative to fabricate a power weeder using locally available materials. In the wetland of the BRRI research field and farmer's field at Jogitola of Gazipur district, the developed power weeder was tested during the boro season of 2017-2018. The average weeding efficiency of the power weeder was 80.38% and 81.43% at the research and farmers' field respectively. The percent of tiller damage was observed 2.78% and 2.81% respectively. 910 m2 h-1 (0.091 ha h-1) was the average effective field capacity of the power weeder. After 5 days, the percentage of weeds revived for power weeder was observed at 32.26% and 34.90% at the BRRI research and farmers' fields, respectively. Weed biomass was found 35.43 gm m-2 in a farmer’s field and 30.88 gm m-2 in the BRRI research field, Gazipur. This machine can be run by one man/woman easily. The weight of the complete weeder is 18.3 kg. The benefit-cost ratio of the weeder is 1.85. Farmers can use this weeder in wetland conditions. In the line transplanted wetland field conditions, the power weeder was found suitable for controlling weeds with minimum standing water. Bangladesh Rice J.26 (1): 47-57, 2022

Stakeholders’ composition, knowledge and use of earth observation data in wetland ecological assessments, Zimbabwe

The study analyses stakeholders’ knowledge and use of earth observation (EO) derived data in the assessment and monitoring of Driefontein and Intunjambili wetlands’ ecological conditions. Data was collected using a questionnaire survey administered to 282 randomly selected households and semi-structured interviews carried out with purposefully selected key informants representing institutional stakeholders. The results of this study show that the stakeholder categories identified in the two wetland areas are government departments, statutory bodies, non-governmental organisations, research institutions, academia and the local people. Most of the institutional stakeholders (55.6%) and household respondents (81.7%) do not have knowledge of EO data application in wetland conditions monitoring. Chi-Square test results further show that the households’ knowledge on use of remotely sensed derived products and services does not vary with age (p > 0.05), marital status (p > 0.05), level of education (p > 0.05), except gender in Driefontein (p < 0.05). However, the various stakeholder categories recommended wider application of earth observation products and services in the assessment of land use land cover changes, water quantity and quality, flood monitoring, fire outbreaks and the establishment of a wetland inventory to abate wetland degradation. The utilisation of EO data is constrained by lack of knowledge on the use of remotely sensed data in wetland ecological conditions assessment. Investment in capacity building initiatives for both technical and non-technical stakeholders involved in wetland management in Zimbabwe is required so as to enhance their skills in EO data utilisation.

A Comprehensive Multi-Metric Index for Health Assessment of the Poyang Lake Wetland

The Poyang Lake wetland is home to many unique and threatened species. However, it has been severely degraded in recent decades due to the joint effects of human influence and climate change. Here we establish a wetland health index (WHI) for Poyang Lake, which considers five types of attributes (biological, water quality, sediment, land use and remote sensing, and socio-economic attributes) of the wetland to evaluate wetland conditions. Forty-nine variables across five categories were assembled as candidate metrics for the WHI through field surveys conducted in 2019 at 30 sample sites. Principal component analyses were performed to identify the most important variables in each of the five categories as the primary metrics of each index category (e.g., biological index). Eighteen variables were finally selected from the five categories to construct the WHI. The WHI scores varied from 0.34 to 0.80 at the 30 sample sites, with a mean of 0.55. The Poyang Lake wetland is generally in fair condition according to our WHI scores. Sample sites where connected rivers flow into the lake were assessed to be in a poor condition, highlighting the importance of reducing pollution input from rivers for wetland conservation. Scores of individual indices of the five categories were not highly correlated (0.29 ≤ pairwise Spearman’s r ≤ 0.69), suggesting that information provided by each index is different and might be complementary. The composite WHI as well as the individual category indices can provide comprehensive information on wetland conditions that would facilitate the development of more targeted and effective strategies for wetland management.

Effectiveness of rapid sampling assessments for wetland-breeding amphibians

A primary response to the Clean Water Act has been the development of numerous indices of biotic integrity (IBI) using various taxonomic groups to assess the condition of water bodies in the United States. The IBI is a frequently used approach for assessing the ecological integrity of streams; however, it is less commonly applied to wetland systems, despite the scientific and policy needs to assess wetland condition and develop ecological performance goals for wetland monitoring, creation, and restoration. Although a great deal of attention has been given to wetland acreage due to the “no net loss” policy over the past two decades, much less attention has been given to the ecological integrity of these same wetlands. To assess wetland health and function, regulatory agencies and land managers need clear performance standards that are based on the ecology of wetland organisms. To address this need, we sampled 242 wetlands distributed across 45 managed properties in Illinois, U.S.A. over three years (2012–2014) for adult and larval amphibians (12 samples per wetland). Amphibian assemblages make up critical ecological components of many wetland ecosystems and are considered useful bioindicators of environmental change because they are sensitive to various forms of environmental and habitat alteration. We developed an amphibian-based IBI (hereafter aIBI) for the assessment of seasonal wetlands and optimal sampling strategies to best quantify these wetlands (i.e., assessment of time and effort). The aIBI applied a conservation coefficient to all species captured; conservation coefficients were developed through a survey of amphibian experts (n = 16). We captured 25 amphibian species with an average of 7.11 amphibian species (range 1–13) per site. Using the species occurrence data collected from both dipnet and minnow trap surveys over 12 survey periods, we assessed the average percent error in the estimation of aIBIs and species richness. Our results show that a wetland can be accurately evaluated with amphibians in one field season, but that multiple samples during that field season will be necessary. We show that 4–5 surveys using multiple methods distributed throughout the spring and summer are required. This level of effort may be incongruent with existing definitions of ‘rapid assessment’, but it is the necessary level of effort needed to confidently and accurately evaluate wetlands using amphibians as an indicator taxon. Additionally, aIBI provides a more robust framework to assess wetland integrity compared to simple species richness or other similar methodologies.

Multi-sensor and multi-platform retrieval of water chlorophyll a concentration in karst wetlands using transfer learning frameworks with ASD, UAV, and Planet CubeSate reflectance data

China has one of the widest distributions of carbonate rocks in the world. Karst wetland is a special and important ecosystem of carbonate rock regions. Chlorophyll-a (Chla) concentration is a key indicator of eutrophication, and could quantitatively evaluate water quality status of karst wetland. However, the spectral reflectance characteristics of the water bodies of karst wetland are not yet clear, resulting in remote sensing retrieval of Chla with great challenges. This study is a pioneer in utilizing field-based full-spectrum hyperspectral data to reveal the spectral response characteristics of karst wetland water body and determine the sensitive spectral bands of Chla. We further evaluated the Chla retrieval performance of multi-platform spectral data between Analytical Spectral Device (ASD), Unmanned aerial vehicle (UAV), and PlanetScope (Planet). We proposed two multi-sensor weighted integration strategies and two transfer learning frameworks for estimating water Chla from the largest karst wetland in China by combing a partial least square with adaptive ensemble algorithms. The results showed that: (1) In the range of 500–850 nm, the spectral reflectance of water bodies in the karst wetland was overall 0.001–0.105 higher than the inland water bodies, and the sensitive spectral ranges of water Chla focus on 603–778 nm; (2) UAV images outperformed ASD and Planet data, and produced the highest inversion accuracy (R2 = 0.670) for water Chla in karst wetland; (3) Multi-sensor weighted integration retrieval methods improved the Chla estimation accuracy (R2 = 0.716). Integration retrieval methods with the different weights produced the better Chla estimation accuracy than that of methods with the equal weights; (4) The transfer learning methods from ASD to UAV platform provided the better retrieval performance (the average R2 = 0.669) than that of methods from UAV to Planet platform. The transfer learning methods obtained the highest estimation accuracy of Chla (R2 = 0.814) when the ratio of the training and test data in the target domain was 7:3. The transfer learning methods produced the higher estimation accuracies with the distribution of the absolute residuals between predicted and measured values <20.957 mg/m3 compared to the multi-sensor weighted integration retrieval methods, which demonstrated that transfer learning is more suitable for estimating Chla in karst wetland water bodies using multi-platform and multi-sensor data. The results provide a scientific basis for the protection and sustainable development of karst wetlands.

Status of river-connected lakes under the influence of the Three Gorges Dam: research progress and prospect

The construction and operation of the Three Gorges Dam, the world's largest dam, has provided important support for national economic development and drinking water safety. However, the dam's construction has had a non-negligible impact on the ecosystem condition of lake wetlands in the middle and lower reaches of the Yangtze River, which has become a significant theme in recent scientific researches and policy works. Although previous studies have carried out detailed assessments of the relationship between the Three Gorges Dam and downstream lake wetland ecosystems, there has not been a comprehensive discussion. Based on the bibliometric method and the systematic collation of related research, this paper comprehensively reviewed the research progress and hot topics of the river-connected lakes in the middle and lower reaches of the Yangtze River under the influence of the Three Gorges Project. The results show that the number of related studies continued to grow during the study period, involving multiple research fields. The research hotspots focused on five fields: schistosomiasis, remote sensing monitoring of the landscape, water quality, water level and sediment. The disturbance of the Three Gorges Dam on lake water level, landscape heterogeneity and habitat quality may be the focus of further research. In addition, this study presents challenges and recommendations for future research directions. This paper aims to provide a constructive reference for the management of the Three Gorges Dam and the conservation and restoration of lake wetland ecosystems.

Assessing Nutrient Assimilation by Wetland Impoundments Across Environmental Gradients

Wetland impoundments are constructed for recreational and conservational purposes. Here, the water level can be carefully controlled, producing ideal conditions for aquatic plant growth to support migratory birds or other management goals. These wetlands also perform a critical function of nutrient assimilation, with the capability to protect downstream waters from eutrophication. Understanding how the structural characteristics of wetlands are related to this functional capacity within shallow impoundments will help inform management practices to improve overall wetland function. We characterized 18 waterfowl impoundments surrounding the Great Salt Lake, Utah, USA. Wetland assimilation of nitrogen (N) and phosphorus (P) was estimated at each wetland by controlled nutrient addition within mesocosms. In addition, wetland condition was assessed using a multimetric index (MMI), an indicator of the biological quality of the wetlands. We found that N assimilation was inversely correlated with water depth and positively correlated with soil % clay and total iron. Phosphorus assimilation was related to dissolved oxygen, aluminum, and N and P concentrations within the water column and soil. Nutrient assimilation did not differ among wetlands rated as poor, fair, and good by the MMI.

Ecosystem health assessment and comparison of natural and constructed wetlands in the arid zone of northwest China

Wetlands in the arid zone of northwest China have ecological values such as climate regulation, water conservation, and biodiversity maintenance. However, in the context of global warming and economic development, the degree of natural and human interference in the wetlands has been increasing, and wetland health problems are becoming increasingly severe. The current comparative research on the ecosystem health evaluation of natural and constructed wetlands and their sustainable development in the arid zone of northwest China is not perfect, so we selected the natural (Dunhuang Xihu Wetland) and constructed wetlands (Suzhou District Wetland) as research objects. The ecosystem health evaluation system has been developed from 5 levels of the drive, pressure, state, impact, and response (DPSIR). The ecological health status and impact factors were evaluated for the two wetlands using socioeconomic data combined with remote sensing technology from 2000 to 2019. The results showed that 1) the ecological health of natural and constructed wetlands was in a medium healthy state, and the ecological health values of the wetlands showed a trend of decreasing and then increasing from 2000 to 2019, with 2005 as the turning point. The ecological health status of natural wetlands (0.46) was better than that of constructed wetlands (0.42). 2) The main reasons for the degradation of constructed wetlands (-3.20%) were the urban population expansion and blind agricultural reclamation of wetlands, while the degradation of natural wetlands (-6.45%) was dominated by extreme climatic conditions and overuse of water resources. These results provide case support and a theoretical basis for the conservation management and sustainable development of wetland ecosystems in the arid zone.

Benthic macroinvertebrates community structure and physicalchemical characteristics at Lauca River Basin high altitude wetlands, Altiplano, Chile

High Andean freshwater ecosystems are highly threatened by scarce water availability, species invasion, and global climate change, so generating knowledge about their ecological characteristics is extremely important for conservation decision-making. In this work, the seasonal variations and relationships between physico-chemical variables and the structure and composition of the macroinvertebrate community were analyzed considering “season”, “type of ecosystem” and “site” factors. Five sites of representative ecosystems at Lauca River Basin of the Chilean Altiplano were sampled, two of them lentic and three lotic. Two field-sampling periods within a year according to the pre- and post-rain seasons characteristic of the Altiplano climate were considered. Thirty-five taxa were identified, and it was observed that the taxa Orthocladiinae, Austrelmis sp., Hyallela cf kochi, Podonominae and Helicopsychidae were indicator taxa that contributed the most to differences among sites or ecosystems (≥ 10 %.). No significant differences were found in the alpha diversity indicators used, except for some abundance values and Pielou’s Evenness index (J´), which varied significantly between lotic and lentic systems. The results of the ordination analysis showed a significant differentiation considering physical and chemical variables and macroinvertebrates assemblages that responded to “sites” (ANOSIM R Global = 0.64, p = 0.001) and “type of ecosystem” factors (ANOSIM R Global = 0.31, p = 0.02). The “season” factor was not statistically significant to explain the variability of biological data (ANOSIM R Global = -0.003, p = 0.47) and was slight and marginally significant with the physical and chemical data (ANOSIM R Global = 0.1, p = 0.04). In addition, the linear redundancy analysis (RDA) showed that physico-chemical variables related to hardness, temperature, phosphorous, and nitrogen explained most of the variance in the biological data (the first two canonical axes RDA1 and RDA2 explained 45.23 % of the total variation, p = 0.004). These results support the relevance of local conditions for high altitude wetlands and how those environmental characteristics can be reflected in the macroinvertebrate assemblages that inhabit them.

Composition and structure of water birds in some areas of northwestern Algeria

Wetlands have an inestimable importance in different regions of the world. Algeria is rich in wetlands which are among the most precious resources in terms of biological diversity. Water birds are particularly attractive and important because of their long-distance migrations and their potential as indicators of the status and value of wetlands. This is how; works on the avifauna are still more and rarer, in Algeria and particularly in the area of Tiaret. It’s, with this in mind, that our study, which relates to the assessment of the biodiversity of birds in the wetlands of Tiaret area and Tissemsilt area, over a period of two years, from 2016 to 2018, and this in order to inventory and determine the distribution of all species of birds, photographed or captured and recognize species of ecological, trophic and phenological interest, located in these regions which remains still virgin.

Wetland nitrogen removal from agricultural runoff in a changing climate

Wetlands in agricultural areas mitigate eutrophication by intercepting nutrient transports from land to sea. The role of wetlands for nutrient removal may become even more important in the future because of the expected increase in agricultural runoff due to climate change. Because denitrification is temperature dependent, wetland nitrogen (N) removal usually peaks during the warm summer. However, climate change scenarios for the northern temperate zone predict decreased summer and increased winter flows. Future wetlands may therefore shift towards lower hydraulic loading rate and N load during summer. We hypothesised that low summer N loads would decrease annual wetland N removal and tested this by examining 1.5–3 years of continuous N removal data from created agricultural wetlands in two regions in southern Sweden (East and West) during different periods. West wetlands showed relatively stable hydraulic loads throughout the year, whereas East wetlands had pronounced no-flow periods during summer. We compared East and West wetlands and tested the effects of several variables (e.g., N concentration, N load, hydraulic load, depth, vegetation cover, hydraulic shape) on annual absolute and relative N removal. We found no difference in annual N removal between East and West wetlands, even though summer N loads were lower in East than in West wetlands. A possible explanation is that stagnant water conditions in East wetlands suppressed decomposition of organic matter during summer, making more organic matter available for denitrification during winter. Absolute N removal in all wetlands was best explained by N load and hydraulic shape, whereas relative N removal was best explained by emergent vegetation cover and hydraulic shape. This study highlights the importance of design and location of agricultural wetlands for high N removal, and we conclude that wetlands in a future climate may remove N from agricultural runoff as efficiently as today.

Participatory Rural Appraisal for Assessing Freshwater Wetland Status and Fishery Potential in West Midnapore, West Bengal, India

Participatory Rural Appraisal for Assessing Freshwater Wetland Status and Fishery Potential in West Midnapore, West Bengal, India

Degradation Status and Local Community Perception towards Kadar-Basaso Wetland in Sinana District of Bale Zone, South Eastern Ethiopia

Wetlands are valuable resources that provide a variety of functions for local populations, including environmental, hydrological, and socioeconomic benefits. Despite the importance of wetlands to humanity, they have been largely degraded and even lost in many countries including Ethiopia because they are wrongly regarded as wastelands. Some wetland conservation policies were designed not based on the perceptions of the people residing around the wetlands and lack of attention to communal areas. It is because of this gap that a quantitative analysis of physicochemical soil quality analysis and the local community’s perceptions was carried out with the overall goal of analyzing the degradation status of Kadar-Basaso wetland and community perceptions. A cross-sectional research approach was used with a purposeful soil sampling from/in 6 plots sized 50 m × 50 m and &gt;100 m apart along two transect lines, and 200 household heads chosen randomly from three villages(Basaso, Shallo, and Nano Robe) bordering the wetland. Soil sampling, questionnaires, focus group discussion, and key informant interviews were used to collect data and then examined quantitatively and qualitatively. The result shows that the Kadar-Basaso wetland was moderately degraded. The physicochemical analysis of the soil reveals that the pH was acidic, indicating the presence of acidic waste effluents. In addition, the electric conductivity was salt-free, cation exchange capacity were found to be low, the organic matter was relatively low, potassium levels vary very little, and Phosphorous variation was minimal. Expansion of farmland and Overgrazing were the most damaging elements affecting wetland biodiversity. From the analysis, it was noted that communities’ attitudes influence human activities on the wetland. The study recommends that the government and wetland management authorities must establish strategies to minimize deterioration in the area and offer better infrastructure for both livestock keepers and farmers to improve the long-term usage of wetlands. The best management strategies should be devised for all sizes, types, and all site wetlands.

Integrating temperature gradient-based 3T and resistance-based models for simulating evapotranspiration and its components

The accurate estimation of evapotranspiration (ET) and its major components [e.g., transpiration (Tr) and soil evaporation (Ev)] requires an understanding of complex soil–plant-atmosphere interactions. The temperature gradient-based three temperature (3T) model for simulating the dynamics of Ev and Tr has no requirement for resistance terms and its use of simple input variables (i.e., temperature and radiation) allows its application to both field studies and remote sensing. However, reference temperature is a key requirement for the 3T model and approaches for obtaining accurate reference temperature and the implications of different reference temperature choices on ET estimates remain poorly understood. This study improved a resistance-based model applicable to a wide range of climatic/ecosystem conditions and integrated it with the 3T model to predict ET and Tr. A novel numerical approach was used to estimate the reference temperature under dry land surface scenarios. The two models provided similar predictions of Ev, Tr, and ET at the four sites provided that the available energy for the canopy (e.g., net radiation) and ground soil (e.g., net radiation and ground heat flux) was constrained within the framework of the energy balance. Alternatively, the accuracy of simulations of Ev and ET by the 3T model significantly declined due to systematic mismatching of input drivers (temperature and radiation) under dry and wet scenarios. We emphasize that 3T is working better when input temperature and radiation under dry and wet land conditions were systematically matched within the framework of energy balance. The results of this study provide a promising novel temperature-gradient method for detecting canopy water stress.

Factors affecting the ecological habitat of Benthic macro-invertebrate assemblages in Asan wetland, Dehradun in Garhwal Himalaya

The Himalayan region has several freshwater resources, such as rivers, lakes, and wetlands. These freshwater resources have been adversely affected by environmental factors. Freshwater biological systems are defenseless against outcomes of environmental changes that might prompt the irreversible disintegration of these natural surroundings. The present study aimed to investigate the effect of biotic and abiotic factors on the Benthic macro-invertebrate assemblages of the Asan wetland, Dehradun in Garhwal Himalaya. A determination of the physico-chemical health status of the Asan wetland viz., electrical conductivity (EC), total dissolved solids (TDS), biochemical oxygen demand (BOD), and nutrients parameters like nitrogen, potassium, and phosphorus were investigated during this study. Three sampling sites (Site 1, Site 2 and Site 3) of wetland were selected and the water samples were collected seasonally, i.e., summer, winter, and monsoon from April 2021-March 2022. Maximum values of EC(163.75 µS/cm), TDS (232.78 (mg/l), alkalinity (141.20 mg/l) and pH(7.8) were recorded in the monsoon season (June-September) and minimum values of EC( 135.80µS/cm), TDS (196.80 (mg/l), alkalinity (119.80mg/l) and pH(7.2) were recorded in the winter season (November–February). An overall total of 18 macrobenthos genera belonging to four classes was identified. Maximum communities of macrobenthos were observed during the winter and minimum communities during the monsoon season. Canonical correspondence analysis (CCA) was used to determine whether microbenthic genera and habitat ecological parameters and showed a positive or negative correlation. Thus, the present study contributed to the status of various factors and their impacts on the Benthic macro-invertebrate structure of the Asan wetland.

Beaver pond identification from multi-temporal and multi- sourced remote sensing data

ABSTRACT The maintenance and restoration of wetland habitat is a priority conservation action for most waterfowl and other wetland-dependent species in North America. Despite much progress in targeting habitat management in staging and wintering areas, methods to identify and target high-quality breeding habitats that result in the greatest potential for wildlife are still required. This is particularly true for species that breed in remote, inaccessible areas such as the American black duck, an intensively managed game bird in Eastern North America. Although evidence suggests that black ducks prefer productive, nutrient-rich waterbodies, such as beaver ponds, information about the distribution and quality of these habitats across the vast boreal forest is lacking with accurate identification remaining a challenge. Continuing advancements in remote sensing technologies that provide spatially extensive and temporally repeated information are particularly useful in meeting this information gap. In this study, we used multi-source remotely sensed information and a fuzzy analytical hierarchy process to map the spatial distribution of beaver ponds in Ontario. The use of multi-source data, including a Digital Elevation Model, a Sentinel-2 Multi-Spectral Image, and RadarSat 2 Polarimetric data, enabled us to identify individual beaver ponds on the landscape. Our model correctly identified an average of 83.0% of the known beaver dams and 72.5% of the known beaver ponds based on validation with an independent dataset. This study demonstrates that remote sensing is an effective approach for identifying beaver-modified wetland features and can be applied to map these and other wetland habitat features of interest across large spatial extents. Furthermore, the systematic acquisition strategy of the remote sensors employed is well suited for monitoring changes in wetland conditions that affect the availability of habitats important to waterfowl and other wildlife.