Permanent Water Bodies Research Articles

Assessment of Land Use Land Cover Changes for Predicting Vulnerable Agricultural Lands in River Basins of Bangladesh Using Remote Sensing and a Fuzzy Expert System

The aim of this study was to assess the LULC changes over 26 years from 1995 to 2021 to find the most changed land use conditions within the 25 km territory of the main river systems of Bangladesh. In addition, the prediction of vulnerable areas for agricultural land use in terms of inundation by river water was also analyzed. The study area includes river networks distributed through eight administrative divisions (Rangpur, Rajshahi, Mymensingh, Sylhet, Dhaka, Khulna, Barishal and Chittagong) of Bangladesh, covering an area of 64,556 km2. The study was conducted by identifying permanent water bodies from NDWI indices and preparing LULC maps that include the five main land use classes (water body, bare land, vegetation, agricultural land, and urban area) in the Google Earth Engine platform using supervised classification. The LULC maps were then analyzed in the ArcGIS® environment. A vulnerability map for agricultural land use was also prepared using a fuzzy expert-based system applying multicriteria analysis. From the land use land cover map of the study area, it was found that among the five land use classes, water bodies, bare land, vegetation, and urban areas increased in size by 3.65%, 2.18%, 3.31% and 2.55%, respectively, whereas agricultural land use significantly decreased by 11.68%. This decrease in agricultural land use was common for the analyzed area of all administrative divisions. According to the vulnerable area map of the eight divisions, more than 50% of the analyzed area of the Khulna and Dhaka divisions and more than 40% of the analyzed area of the Rajshahi, Mymensingh, Sylhet, Barishal and Chittagong divisions were highly vulnerable to agricultural land use due to the possibility of inundation by water. However, approximately 44% of the analyzed area of the Rangpur division was not vulnerable for agricultural land use. The prepared LULC and vulnerability maps can be helpful for the future land use planning of Bangladesh to meet the increasing demand for food production and livelihoods for increasing populations.

On the surface or down below: Field observations reveal a high degree of surface activity in a burrowing crayfish, the Little Brown Mudbug (Lacunicambarus thomai)

Opposed to most crayfish species that inhabit permanent bodies of water, a unique burrowing lifestyle has evolved several times throughout the crayfish phylogeny. Burrowing crayfish are considered to be semi-terrestrial, as they burrow to the groundwater-creating complex burrows that occasionally reach 3 m in depth. Because burrowing crayfishes spend most of their lives within their burrow, we lack a basic understanding of the behavior and natural history of these species. However, recent work suggests that burrowing crayfishes may exhibit a higher level of surface activity than previously thought. In the current study, we conducted a behavioral study of the Little Brown Mudbug, Lacunicambarus thomai using video surveillance to determine their degree of surface activity and behavioral patterns. Throughout 664 hrs of footage, we observed a surprisingly high amount of activity at the surface of their burrows-both during the day and night. The percentage of time that individual crayfish was observed at the surface ranged from 21% to 69% per individual, with an average of 42.48% of the time spent at the surface across all crayfish. Additionally, we created an ethogram based on six observed behaviors and found that each behavior had a strong circadian effect. For example, we only observed a single observation of foraging on vegetation during the day, whereas 270 observations of this behavior were documented at night. Overall, our results suggest that burrowing crayfishes may exhibit higher levels of surface activity than previously thought. To increase our understanding of burrowing crayfish behaviors ecology, we encourage the continued use of video-recorded observations in the field and the laboratory.

A methodology for mapping annual flood extent using multi-temporal Sentinel-1 imagery

A novel automated approach for mapping nonurban flood extents using satellite-based Sentinel-1C-band SAR data is presented and applied in the Republic of Ireland. The methodology mapped the maximum flood extent of over 25,000 detected water bodies across Ireland over a five-year period (2016–2021). Flood extents were classified using a semi-automatic tile-based histogram thresholding approach and refined using a series of post processing filters. These included multi-temporal filters which exploited the timing and orbit position of the Sentinel-1 satellite to identify likely false positives, and contextual information based filters which used external information such as topography and land use to estimate the likelihood of flooding and constrain its extent. A topographic correction algorithm was also applied to hydrologically-correct flood bodies. The methodology produced a user accuracy of above 0.95 for each annual map when compared to observed flood level data, overall accuracy values above 0.97 and kp values above 0.7 when compared to mapping process based on Sentinel-2 validation imagery, and the capacity to detect over 90% of recorded permanent water bodies larger than 2 ha. As an additional step, confidence information was provided for each flood polygon based on the quantity of consistently flooded pixels used in its definition. The mapping process represents a stable and systematic nonurban flood mapping methodology that enables inter-annual comparison of flood extent at gauged and ungauged sites.

Diatom diversity, distribution and ecology in Mediterranean ecosystems of Abrau Peninsula, north-western Caucasus.

The North Caucasus is an extensive region with a multitude of landscapes and high biological diversity. Amongst various ecosystems, the xerophytic sub-Mediterranean forests of the Abrau Peninsula (Utrish State Nature Reserve) and its vicinity are unique but have been poorly studied. The diversity of diatoms in North Caucasian ecosystems have been studied partially and only little information is available about their presence and distribution on the Abrau Peninsula. Here, we present a comprehensive check-list of diatoms sampled during a July 2021 field campaign. Samples were collected in 67 sites, including 39 permanent streams, 21 temporal (puddles) and seven permanent waterbodies. Results of the current study contribute to improving the knowledge about diatoms in the north-western Caucasus and its sub-Mediterranean ecosystems in particular. Here, we provide a detailed dataset that contains 215 freshwater and brackish diatom occurrences collected during a field campaign in July 2021. A total of 88 diatom (Bacillariophyta) taxa which belong to 12 orders, 25 families and 39 genera were collected. The genera with the highest number of occurrences per site were Gomphonema (26), Nitzschia (22), Navicula (20), Cocconeis (14), Amphora (14), Achnanthidium (14) and Planothidium (11). The genera with the highest number of infrageneric taxa were Nitzschia (8), Navicula (7), Gomphonema (6) and Mastogloia (5). Naviculablazencicae, known as the endemic of the Lake Prespa (Levkov 2007) is found from two sites in our study. Three specimens of the genus Mastogloia could not be assigned to a known species and may represent new diatom species. Distribution and ecology data are provided for each taxa. Occurrence data are given. Statistical analysis of diatom communities showed a significant dependence on habitat type and their ecological conditions.

Multispectral imagery for detection and monitoring of vegetation affected by oil spills and migration pattern in Niger Delta Region, Nigeria

Oil spills in the Niger Delta area can be detected and monitored using this novel technique. Landsat 5 and 8 images were used to assess various vegetation stress, such as Normalized Difference Vegetation Index, Soil Adjusted Vegetation Index, Atmospheric Resistant Vegetation Index, Green Near Infrared and Green Short-wave Infrared, from the spill site in 2019, non-spill site (1992 pre-oil spill) and 2020 post-oil spill events, respectively. There is a substantial difference (p-value <0.005) in the vegetation conditions at the Spill Site and the non-spill Site in 2020 in terms of NDWI, SAVI, ARVI2 and G-NIR and G-SWIR. NDVI, SAVI, ARVI2, G-NIR, G-SWIR, and G-SWIR. There is a very significant difference in vegetation conditions between the pre-spill event and the post-spill event in 2020 (p-value <0.005). The oil spills' migration patterns and flow directions indicate from north to south along the runoff water using SRTM data. The sentinel 1 data revealed visualization of the flooded areas, including water surfaces that are stable around oil pipelines and the surroundings, using calibration threshold and the RGB band method to distinguish flooded areas from permanent water bodies. This was used to map areas affected by the oil spill on land and water bodies for proper environmental assessment before and during the flood of the oil spill environment. Multi spectral imagery is therefore a veritable tool for detection, response and monitoring of oil spills from pipelines.

Long-term detection and spatiotemporal variation analysis of open-surface water bodies in the Yellow River Basin from 1986 to 2020

Accurately investigating long-term information about open-surface water bodies can contribute to water resource protection and management. However, due to the limits of big-data calculations for remote sensing, there has been no specific study on the long-term changes in the water bodies in the Yellow River Basin. Thus, in this study, we developed a new combined extraction rule to build an entire annual-scale open-surface water body dataset for 1986–2020 with excellent effectiveness in eliminating the interference of shadows in the Yellow River Basin using all of the available Landsat images. For the first time, the spatial distribution, change trends, conversion processes, and the heterogeneity of the surface water bodies in the Yellow River Basin were analyzed comprehensively to the best of our knowledge. The extraction results had an overall accuracy of 99.70 % and a kappa coefficient of 0.90, which were validated using 34,073 verification points selected on high-resolution Google Earth images and random Landsat images. The total area of water bodies initially decreased (1986–2000) and then increased (2001−2020); however, only the size of the permanent water bodies increased in most areas, while the size of most of the seasonal water bodies decreased. In regions with human-made water bodies, the non-water areas were substantially converted to seasonal and permanent water bodies; however, in areas with natural water bodies, many permanent and seasonal water bodies were gradually converted to non-water areas. Thus, most of the increases in the water bodies occurred in the form of artificial lakes and reservoirs, while most of the decreases in the water body area occurred in natural wetlands and lakes. The areas of both the permanent and seasonal water bodies were positively correlated with precipitation, but only the area of the seasonal water bodies was negatively correlated with temperature.

A New Coherence Detection Method for Mapping Inland Water Bodies Using CYGNSS Data

Inland water is an important part of the Earth’s water cycle. Mapping inland water is vital for understanding surface hydrology and climate change. Spaceborne global navigation satellite systems reflectometry (GNSS-R) has been proven to be an effective technique to detect inland water bodies. This paper proposes a new method to map inland water bodies using the delay-Doppler map (DDM) measurements provided by the GNSS-R platform Cyclone GNSS (CYGNSS). In this new method, we develop a refined power ratio to identify the coherence in DDM caused by the inland water. Processed with an image segmentation method, the refined power ratio is then applied to discriminate the permanent inland water bodies from the land. Using CYGNSS data over the Amazon Basin and the Congo Basin in 2020, we successfully generated water masks with a spatial resolution of 0.01°. Compared with the reference optical water masks, the overall detection accuracy in the Amazon Basin is 94.48% and the water detection accuracy is 92.23%, and the corresponding accuracies in the Congo Basin are 96.12% and 93.16%, respectively. Compared with the previous DDM power-spread detector (DPSD) method, the new method’s false alarms and misses in the Amazon Basin are reduced by 17.1% and 9.1%, respectively, while the false alarms and misses in the Congo Basin are reduced by 10.2% and 22%, respectively. Moreover, our method is proven to be useful for detecting short-term flood inundation.

Detection and mapping of May 2021 flood in Beaufort, Sabah using Sentinel-1 SAR and Sentinel-2 multispectral in Google Earth Engine

Recurring floods severely impacted the livelihood and socio-economic. It causes disruption of clean water, electricity, communications, properties damages and sometimes loss of life. Information on flooded areas is crucial for effective emergency responses support. In this study we used Sentinel 1 (S-1) C-band and Sentinel 2 (S-2) Multispectral satellite imageries where wider area covered in 12 days repeat satellite pass. The flood event on the 26 May 2021 was identified and we retrieved the S-1 GRD SAR imagery and S-2 level-2A BOA in GEE environment. We analysed the S-1 VV, VH, VV/VH imagery by pixels clustering using object based SNIC classification and Machine Learning (ML) algorithm for extraction of waterbody. Meanwhile for the S-2 we used MNDWI and extracted the waterbody area using thresholding value. We obtained the final flooded area of S-1 and S-2 by subtraction with permanent waterbody. The S-2 flood estimation results were better than S-1. However, S-2 limited to cloud free and less cloudy coverage while S-1 lacking of ability to identify flood in detailed was influenced by slope shadow area. This study provides the basis of detection and mapping floods using S-1 and S-2 imageries through Machine Learning techniques in GEE for local scope of Sabah, Borneo region and Malaysia.

Larval biotopes of mosquitoes (Diptera: Culicidae) on the Berezinsky Biosphere Reserve (Belarus)

The purpose of the research is to study of larval biotopes of the family Culicidae Meigen, 1818 on the territory of the Berezinsky Biosphere Reserve.Materials and methods. Mosquito larvae collected on the Berezinsky Biosphere Reserve in 2016–2020. A total of 7772 mosquito larvae were collected in the course of 1467 counts. Mosquito larvae were collected in four types of natural reservoirs: permanent open (I); permanent shaded (II); temporary open (III) and temporary shaded (IV). The larvae were collected by dip net. The specimens were identifed using standard keys; in certain cases, the taxonomic collection of the Zoological Institute of the Russian Academy of Sciences (St. Petersburg) was used.Results and discussion.We found larvae of 22 mosquito species on the Berezinsky Biosphere Reserve. The genus Aedes Meigen, 1818 is the most abundant – 16 species (72,7%). The genus Anopheles Meigen, 1818 is represented by 2 species (9,2%), the genus Culiseta Felt, 1904 – 3 species (13,6%) and the genus Culex Linnaeus, 1758 – 1 species (4,5%). The largest number of species (18) is recorded in permanent and temporary open-type reservoirs, 17 – in temporary shaded reservoirs and the smallest number – 6 in permanent shaded reservoirs. Three species, Aedes vexans (Meigen, 1830), Ae. cantans (Meigen, 1818), and Ae. sticticus (Meigen, 1838) were found at all types of water bodies. The main larval breeding habitats are reservoirs of temporary origin with varying degrees of shading (88,0%). There are the highest abundance and mean average density of larvae. Thus, in temporary open water bodies, the abundance is 52,4% (with an average density of 197,0±45,7 sp./m2), and in temporary shaded water bodies, the abundance is 35,5% (with an average density of 287,2±162,1 sp./m2). For permanent reservoirs with varying degrees of shading, a low abundance and an average density of larvae are noted. Thus, in permanent open water bodies, the abundance is 9,6% (with an average density of 27,0±7,7 sp./m2), and in permanent shaded water bodies, the abundance is 2,5% (with an average density of 19,4±6,0 sp./m2). In permanent open water bodies, the greatest species diversity is noted, which is confrmed by the values of the indices (Нʹ = 3,06; D Mg = 2,57 and DSm = 0,16).

ASTER GLOBAL DEM (GDEM) VERSION 3

Abstract. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a 14-channel imaging instrument operating on NASA’s Terra satellite since 1999. ASTER’s visible–near infrared (VNIR) instrument, with three bands and a 15 m Instantaneous field of view (IFOV), is accompanied by an additional VNIR band using a second, backward-looking telescope. Collecting along-track stereo pairs, the geometry produces a base-to-height ratio of 0.6. In 2009, the ASTER Science Team released Version 1 of the global DEM (GDEM) based on stereo correlation of 1.2 million ASTER scenes. The DEM has 1 arc-second latitude and longitude postings (∼30 m) and employed cloud masking to avoid cloud-contaminated pixels. The GDEM covers all of the Earth’s land surface from 83 degrees north to 83 degrees south latitude. Version 2 was released in 2011, with notable improvements in coverage and accuracy. In 2019, the final, Version 3, was released; again improving on coverage and removing almost all artifacts. Th GDEM is a unique, global high spatial resolution digital elevation dataset available to all users at no cost. In addition, a second unique dataset was produced and released. The raster-based ASTER Global Water Body Dataset (ASTWBD) identifies the presence of permanent water bodies, and marks them as ocean, lake, or river. An accompanying DEM file indicates the elevation for each water pixel. To date, over 110+ million 1×1 degree GDEM tiles have been distributed.

Hazard Flood Mapping and Monitory in Parts of the Niger Delta Region Using Sentinel 1 Synthetic Aperture Radar

In this study, the RGB band and threshold techniques were used to distinguish between the flooded area and permanent water bodies with the use of Sentinel 1 images to map and monitor flood hazards in Yenagoa, Bayelsa State. The acquired images were before the flood events in January 2019 and during the events in October and November 2019 with the aid of Snap 7.0 and ArcGIS software. The preprocessing of Sentinel-1 images and the mapping procedure have been described in detail, and the results have been evaluated. The results show that the Sentinel 1 sensor can rapidly provide quality data in mapping floods. The applied techniques, RGB and Threshold, show a clear disparity between permanent water bodies and floods by applying contact stretch to histograms. Zones with low backscatter signify flooded areas in red, with high radar response signifying land in the archive indicating surfaces. Areas with black indicate permanent waterbodies, while areas with white indicate built up areas. The estimated significant difference in mean water surface for January and October 2019 is -0.23 dB, while for January and November 2019 it is-0.36 decibels (dB). The difference between October and November 2019 is -0.12 decibels (dB) for the estimated mean water surface in the study area. Therefore, emphasizing remote sensing and GIS as essential tools for flood mapping, risk analysis, and better flood management is therefore essential.

Continuous Monitoring of the Surface Water Area in the Yellow River Basin during 1986–2019 Using Available Landsat Imagery and the Google Earth Engine

The Yellow River Basin (YRB) has been facing severe water shortages; hence, the long-term dynamic monitoring of its surface water area (SWA) is essential for the efficient utilization of its water resources and sustainable socioeconomic development. In order to detect the changing trajectory of the SWA of the YRB and its influencing factors, we used available Landsat images from 1986 through to 2019 and a water and vegetation indices-based method to analyze the spatial–temporal variability of four types of SWAs (permanent, seasonal, maximum and average extents), and their relationship with precipitation (Pre), temperature (Temp), leaf area index (LAI) and surface soil moisture (SM).The multi-year average permanent surface water area (SWA) and seasonal SWA accounted for 46.48% and 53.52% in the Yellow River Basin (YRB), respectively. The permanent and seasonal water bodies were dominantly distributed in the upper reaches, accounting for 70.22% and 48.79% of these types, respectively. The rate of increase of the permanent SWA was 49.82 km2/a, of which the lower reaches contributed the most (34.34%), and the rate of decrease of the seasonal SWA was 79.18 km2/a, of which the contribution of the source region was the highest (25.99%). The seasonal SWA only exhibited decreasing trends in 13 sub-basins, accounting for 15% of all of the sub-basins, which indicates that the decrease in the seasonal SWA was dominantly caused by the change in the SWA in the main river channel region. The conversions from seasonal water to non-water bodies, and from seasonal to permanent water bodies were the dominant trends from 1986 to 2019 in the YRB. The SWA was positively correlated with precipitation, and was negatively correlated with the temperature. Because the permanent and seasonal water bodies were dominantly distributed in the river channel region and sub-basins, respectively, the change in the permanent SWA was significantly affected by the regulation of the major reservoirs, whereas the change in the seasonal SWA was more closely related to climate change. The increase in the soil moisture was helpful in the formation of the permanent water bodies. The increased evapotranspiration induced by vegetation greening played a significant positive role in the SWA increase via the local cooling and humidifying effects, which offset the accelerated water surface evaporation caused by the atmospheric warming.

Amphibian and reptilian fauna from the early Miocene of Echzell, Germany

The present study describes a rich amphibian and reptilian assemblage from the early Miocene locality Echzell, Germany. It consists of one allocaudate, five salamander, five frog, one gecko, chamaeleonids, anguine lizards, one lacertid, one skink and five snake taxa. The entire herpetofauna of Echzell is represented by genera and/or families very broadly known from the early Miocene of Europe. Contrary to other early Miocene herpetofaunas, the Echzell assemblage includes surprisingly only one form of crocodile-newts (Chelotriton). The EchzellPalaeobatrachus robustusrepresents the youngest record of the species and extends its stratigraphic range to the late early Miocene. Regarding chameleons, the frontal is partly preserved, but represents the first described frontal of the extinct speciesChamaeleo andrusovi. The only anguine lizard that can be identified in the assemblage is represented by a new genus and speciesSmithosaurus echzellensis.Our phylogenetic analyses consistently recovered it as the sister taxon to either [Ophisauriscus quadrupes+Ophisaurus holeci] + [Anguis+Ophisaurus] (in the first analysis) or [Anguis+Ophisaurus] (in the second analysis). However, the results are based on limited fossil material – the parietal – and the support for the clade is very low. Thus, the interpretation of theSmithosaurusrelationship among anguines needs to be taken with caution and has to be tested in further studies. Among snakes,Natrix longivertebratarepresents the oldest record of the species and extends the stratigraphic range of this fossil snake back to the early Miocene. In addition, we provide here a broader comparison of the Echzell amphibian and reptilian assemblage with their European records for the MN3 and MN4 biostratigraphical units. Besides that, the entire herpetofauna of Echzell includes very broadly known early Miocene European forms. Remains of other groups of the same period such as Bufonidae, Hylidae, Pelodytidae, Amphisbaenia, Varanidae, Cordylidae,Pseudopus, are not found in the material available to us. We also conclude that the amphibian and reptilian fossil record across MN3–MN4 is significantly biased by taphonomic and/or environmental conditions. The amphibian and reptilian assemblage of Echzell is rich in forms living in humid and warm environments with forested areas, permanent water bodies and also some open habitats. The following climatic parameters can be reconstructed based on the herpetofauna: a mean annual temperature of 17.4–28.8 °C, minimal warm month temperature 18–28.3 °C, minimal cold month temperature 8–22.2 °C, and mean annual precipitation with a value of 791±254 mm.

Ecological and parasitological characteristics of the “Fasciola hepatica L.–Lymnaea (Galba) subangulata” system

Background. Fasciolosis is one of the most common zoonoses in the world, caused by the trematode Fasciola hepatica L. This helminthiasis leads to significant economic damage in animal husbandry and can pose a direct threat to human health. Today, in the context of climate change, detailed knowledge of the biological characte­ristics of the trematode F. hepatica circulation will make it possible to predict outbreaks of fasciolosis on farms in detail and plan effective measures to combat this dangerous disease. The purpose of this work is to clarify some aspects of F. hepatica biology within Berdychiv district belonging to the forest-steppe zone of Zhytomyr region. Material and Methods. The work was carried out during 2020–2021. Collections of mollusks from water bodieson the territory of Berdichevsky district of Zhytomyr region served as the material for the research. Their identification was carried out by conchological features. Conventional methods were used for the parasitological study of mollusks. In total, more than 2000 mollusks Lymnaea (Galba) spp. were examined. Sampling of water and mollusks was carried out from four pasture reservoirs. Results. The main intermediate host of F. hepatica is the mollusk L. (G.) subangulata in the territory of Berdychiv region; L. (G.) truncatulaplays a secondary role in the distribution of this trematode. It was noted that the carriers of F. hepatica partenites are mainly mollusks with a shell height of 4.0 to 8.2 mm. New data on the dynamics of infection of L. (G.) subangulata with the trematode F. hepatica was obtained. The dynamics of infestation of these mollusks with F. hepatica cercariae shows a stable uniform character in the form of a two-peak curve, with peaks in May (2.51 ± 0.88 %) and August (9.19 ± 1.78 %). The overall prevalence of L. (G.) subangulata invasion by fasciola cercariae in the studied water bodies in 2020 was significantly lower than in 2021. Conclusions. In modern climatic conditions, in the territory of the region, permanent water bodies have become fasciolosis foci and common places for the settlement of L. (G.) subangulata, infected with F. hepatica cercariae. The most favorable environmental conditions for fasciola and its intermediate hosts develop in spring; accordingly; for the definitive hosts, this period is quite dangerous in terms of infection of animals.

Effects of elevated temperature, reduced hydroperiod, and invasive bullfrog larvae on pacific chorus frog larvae.

Climate change and invasive species threaten many ecosystems, including surface freshwater systems. Increasing temperatures and reduced hydroperiod due to climate change may promote the persistence of invasive species and facilitate new invasions due to potentially higher tolerance to environmental stress in successful invaders. Amphibians demonstrate high levels of plasticity in life history characteristics, particularly those species which inhabit both ephemeral and permanent water bodies. We tested the influence of two projected effects of climate change (increased temperature and reduced hydroperiod) on Pacific chorus frog (Pseudacris regilla) tadpoles alone and in combination with the presence of tadpoles of a wide-spread invasive amphibian, the American bullfrog (Lithobates catesbeianus). Specifically, we explored the effects of projected climate change and invasion on survival, growth, mass at stage 42, and development rate of Pacific chorus frogs. Direct and indirect interactions between the invasive tadpole and the native tadpole were controlled via a cage treatment and were included to account for differences in presence of the bullfrog compared to competition for food resources and other direct effects. Overall, bullfrogs had larger negative effects on Pacific chorus frogs than climate conditions. Under future climate conditions, Pacific chorus frogs developed faster and emerged heavier. Pacific chorus frog tadpoles developing in the presence of American bullfrogs, regardless of cage treatment, emerged lighter. When future climate conditions and presence of invasive American bullfrog tadpoles were combined, tadpoles grew less. However, no interaction was detected between climate conditions and bullfrog presence for mass, suggesting that tadpoles allocated energy towards mass rather than length under the combined stress treatment. The maintenance of overall body condition (smaller but heavier metamorphs) when future climate conditions overlap with bullfrog presence suggests that Pacific chorus frogs may be partially compensating for the negative effects of bullfrogs via increased allocation of energy towards mass. Strong plasticity, as demonstrated by Pacific chorus frog larvae in our study, may allow species to match the demands of new environments, including under future climate change.

Invertebrate beta diversity in permanent and temporary lentic water bodies: a meta-analytic assessment

Invertebrate beta diversity in permanent and temporary lentic water bodies: a meta-analytic assessment

Flood Monitoring by Integrating Normalized Difference Flood Index and Probability Distribution of Water Bodies

Climate change has caused an increase in the frequency of flood events. Rapid and accurate flood mapping is essential for disaster monitoring and risk assessment. The normalized difference flood index (NDFI) is a change detection method with the characteristics of efficient processing and less manual intervention, which can quickly obtain flood information. However, the NDFI method would misclassify some permanent water bodies in lakes and rivers into floods. We presented a framework by combining NDFI calculated from synthetic aperture radar images and a summer permanent water bodies (SPWB) exclusion layer derived from optical remote sensing surface reflectance data, abbreviated as NDFI-SPWB. This framework was further verified by the flood event in the Yangtze river basin in July 2020. Results show that the NDFI-SPWB framework can increase the user accuracy by approximately 10% and the Kappa coefficient by approximately 0.08 compared with the original NDFI method, which verifies the feasibility and effectiveness of the proposed framework.

Characterization of the anopheline vector breeding habitats: Implications for elimination of malaria in tribal inhabited Car Nicobar Island.

Malaria is an important public health problem in Andaman & Nicobar archipelago. Among the three districts, Nicobar is the most endemic district where API is >2. In this district, the malaria incidence in Car Nicobar Tehsil has declined steadily over the past 10 years. A renewed initiative to consolidate this gain is being made with the ultimate objective of achieving zero indigenous transmission of malaria in Car Nicobar. So, the present study undertook a close environmental monitoring of water bodies for assessing changes in the risk potential of mosquito vector breeding habitats which can augment the elimination programme. The breeding habitats of anopheline mosquitoes were sampled in 16 areas of Car Nicobar Island for eight time periods during 2017-2020. Along with anophelines, various associated water parameters (n=60) were estimated, viz. physicochemical (n=13), and biological, which included culicine mosquito immatures, insect predators (n=5), phytoplanktons (n=31) and zooplanktons (n=10). In the 16 study sites, overall 1126 surface water stagnating bodies constituting 21 different habitat types were surveyed. Of these, 17 were positive for anopheline breeding. Water bodies from three villages were consistently found to be positive for anopheline breeding. However, early instars of anopheline larvae were more abundant compared to the late instars. Four anopheline species were recorded, including Anopheles sundaicus, A. barbirostris, A. insulaeflorum and A. subpictus, in which 48 per cent were A. sundaicus. Multivariable analysis indicated that anopheline density was significantly higher in permanent water bodies than in temporary habitats (P<0.05) (high risk of anophelines). The highest pH (≥8.2), dissolved solids (≥0.39) levels showed significantly (P<0.05) decreased larval densities (lower risk of breeding), adjusted with breeding sites and season. Nitrite levels increased (P=0.022) larval densities. The present study facilitated estimating the productive period of a larval habitat enabling target larval sources to reduce adult populations. Implementing larviciding strategy before monsoon season is presumably the most cost-effective strategy. The output can be utilized for environmental monitoring of mosquito breeding risk in other malaria endemic areas, particularly where medium/large water bodies are the predominant breeding sites for malaria vectors.

Integrating SAR and Optical Remote Sensing for Conservation-Targeted Wetlands Mapping

The Prairie Pothole Region (PPR) contains numerous depressional wetlands known as potholes that provide habitats for waterfowl and other wetland-dependent species. Mapping these wetlands is essential for identifying viable waterfowl habitat and conservation planning scenarios, yet it is a challenging task due to the small size of the potholes, and the presence of emergent vegetation. This study develops an open-source process within the Google Earth Engine platform for mapping the spatial distribution of wetlands through the integration of Sentinel-1 C-band SAR (synthetic aperture radar) data with high-resolution (10-m) Sentinel-2 bands. We used two machine-learning algorithms (random forest (RF) and support vector machine (SVM)) to identify wetlands across the study area through supervised classification of the multisensor composite. We trained the algorithms with ground truth data provided through field studies and aerial photography. The accuracy was assessed by comparing the predicted and actual wetland and non-wetland classes using statistical coefficients (overall accuracy, Kappa, sensitivity, and specificity). For this purpose, we used four different out-of-sample test subsets, including the same year, next year, small vegetated, and small non-vegetated test sets to evaluate the methods on different spatial and temporal scales. The results were also compared to Landsat-derived JRC surface water products, and the Sentinel-2-derived normalized difference water index (NDWI). The wetlands derived from the RF model (overall accuracy 0.76 to 0.95) yielded favorable results, and outperformed the SVM, NDWI, and JRC products in all four testing subsets. To provide a further characterization of the potholes, the water bodies were stratified based on the presence of emergent vegetation using Sentinel-2-derived NDVI, and, after excluding permanent water bodies, using the JRC surface water product. The algorithm presented in the study is scalable and can be adopted for identifying wetlands in other regions of the world.

PALEOENVIRONMENTAL ANALYSIS OF A LOWER CRETACEOUS PALEOLAKE FROM THE IGUATU BASIN BASED ON ITS OSTRACOD FAUNA AND XRF DATA

ABSTRACTThis paper presents the results of a paleoenvironmental study of two Hauterivian–Aptian adjacent sections (Transnordestina A/B) of the Iguatu Basin using ostracods and aided by X-ray fluorescence (XRF), total organic carbon (TOC), total sulfur (S), and spectral analyses. Cluster analysis divided the 10 genera found into two main groups: one composed of Alicenula-Pattersoncypris?-Brasacypris-Hastacypris-Ilyocypris?, and the second composed of Cypridea-Looneyellopsis-Rhinocypris?. The first group is interpreted as representing paleoenvironments with permanent waterbodies, such as lakes, and the second as being indicative of ephemeral settings, such as temporary pools in an inundation plain. XRF analysis using the positive peaks of Ca/Ti and Ca/ΣTi, Fe, Al ratios show a few dry periods, particularly in the lower and middle part of Transnordestina A, between 0 to 175 m and 385 to 475 m, which also display a small number of ostracods. Total S shows several high peaks which might be indicative of gypsum deposition during droughts. Spectral analysis of molar Ti/Al ratio shows two intervals with different sedimentation rates, between 0 and 233 m, and 233 to 836 m. For the first interval, six 100 ka eccentricity cycles were identified; the low number of ostracods for the interval and highly variable Ca/Ti and Ca/ΣTi, Fe, Al values indicate a different sedimentation rate in a drier environment. For the second interval, ten 405 ka cycles were identified; its higher ostracod count and more stable Ca/Ti and Ca/ΣTi, Fe, Al values could be indicative of increasing humidity.