Permanent Water Bodies Research Articles

Eemian paleoenvironment based on the freshwater malacofauna and isotope record (Piła site; north-western Poland)

This article presents the results of malacological and isotope studies on lacustrine sediments from the Eemian interglacial site in the Piła (north-western Poland). Twenty species of molluscs were found in the analysed sediments. Changes in the taxonomic composition and the quantitative structure of malacofauna in the profile allowed distinguishing five types of assemblages corresponding to different phases of the lake's evolution. Ratios of oxygen and carbon isotopes (δ18O and δ13C) reflecting changes in the lake water composition were measured in shells of two predominating snail species, Valvata piscinalis (Müller, 1774) and Bithynia tentaculata (Linnaeus, 1758), and in opercula of Bithynia tentaculata. Significant variability in isotope contents was noted for shells in individual profile sections and between analysed taxa. The results of malacological and isotope studies were supplemented with lithological, stratigraphical and palynological data. On this basis, the sediments age was determined (optimal and suboptimal phases of the Eemian interglacial). Environmental changes of paleolake have been also reconstructed. The analysed sediments were initially deposited in the coastal, periodically drained zone of the reservoir. The younger part of the sequence represents the shallow part of the littoral zone of the permanent water body. The malacological and isotope data also allowed distinguishing two phases of increased water level in the reservoir, and changes in its trophic state probably generated by climatic factors.

Phyllodiaptomusparachristineae, a new species of copepod (Copepoda, Calanoida, Diaptomidae) from the floodplain of the lower Mekong River Basin in Thailand and Cambodia.

Phyllodiaptomus (Phyllodiaptomus) parachristineaesp. nov., a new diaptomid copepod, was collected from 30 sites in the lower Mekong River Basin floodplain in northeastern Thailand and nine sites in Cambodia. The new species is the 13th species of the genus to have been recorded across Asia. It has a wide range of habitats, occurring in small to large, temporary to permanent water bodies, and it can be found at any time of the year. The morphology of the new species is most similar to that of the males of P. (P.) christineae, having a comb on the antepenultimate segment on the right antennule, symmetrical caudal rami, a narrow hyaline lamella on the left P5 basis, a distal accessory spine on the right P5Exp-2, and a single-lobed Enp on the right P5. On the other hand, the males of the new species have second and third urosomites without hair-like setae on the ventral margin, a rounded distal margin of the P5 intersclerite plate, a semi-circular lamella on the right P5 basis, a strong principal lateral spine inserted at the proximal 1/3 of the right P5Exp-2, and a two-segmented left P5Enp. Morphological differences among species in the subgenus Phyllodiaptomus (Phyllodiaptomus) as well as the distribution and habitats of the 13 species and two subspecies of Phyllodiaptomus in Asia are discussed.

Remote sensing and GIS tool application for tracing the water body of Bangalore area

To comprehend the function of the water bodies at various sizes, such as regional and global, for example, in biogeochemical cycles, it is necessary to more correctly estimate the size, form, and extent of the water bodies. Excluding the few areas with precise maps, scaling upward to vast area regions relies on statistical estimates of the number and size of lakes, rivers, and other water bodies, which explains why estimates are wrong. In comparison to the currently available conventional and frequently used methods of mapping land surface water (LSW), remote sensing offers several extra advantages since it is a more accurate, efficient, and reliable information source with the ability to make multiple high-frequency and repeatable quantities of observations. This project describes the development and technological evolution of the Water Body Map (WBM), which employs an automated algorithm to interpret multi-temporal Landsat images from the USGS database. In this project, we used Landsat 5 band photographs to define a water body map without any cloud cover. Permanent water bodies were separated from temporary water-covered areas by estimating the frequency of water bodies in overlapping, multi-temporal Landsat images. In contrast to past studies, the WBM now makes a more precise distinction between rivers and floodplains by looking at the frequency of water bodies. As a result, it is clear that using multi-temporal images from sources is equally as important for mapping global water bodies as analysis at a higher resolution. The classification's accuracy was confirmed in Hokkaido (Japan) and the United States of America using databases of actual water bodies. Around 70% of lakes N1 km2 have relative water area errors of b25%, and the commission error was diminishing and nearly nonexistent. The Water Body Mapping's overall accuracy should be helpful for much larger scale research projects in hydrology, biogeochemistry, and climate systems, among other things. It can also include a quantification of the kinds of water bodies that are currently present around. Some smaller water bodies were overlooked, primarily because shoreline pixels were not included. The primary goal of this project was to estimate the accuracy of mapping water bodies using Landsat 5 TM data by employing straightforward digital image processing techniques.

Natural history and ecology of the slender crayfish (Faxonius compressus): an ecosystem engineer in the Western Highland Rim, USA

ABSTRACT Ecosystem engineers influence the physical environment, which changes the distribution and availability of resources to other organisms. Based on their burrowing abilities, freshwater crayfish have been widely recognised as ecosystem engineers. Crayfishes construct burrows that range from simple, rudimentary depressions in aquatic systems, to complex, labyrinth-like terrestrial burrows that may be significant distances from permanent water bodies. Here, we investigate ecosystem engineering and burrowing of the slender crayfish, Faxonius compressus, which lives in lotic environments characterised by an abundance of small cobble- and gravel-sized substrates. Without larger substrates to burrow under, we found F. compressus populations construct extremely high densities of burrows across riffle, run and pool macrohabitats. Based on the average number of burrows, a 5 × 100 m pool is estimated to contain an average of 25,860 burrows. We also conducted behavioural observations of this species to glean information on their natural history. Faxonius compressus regularly inhabits and competes for ownership of burrows which serve as a shelter from predators. Importantly, these burrows are not only used by F. compressus; we documented other crayfishes and fish species utilising these burrows. In total, we documented two other crayfishes and six fish species utilising F. compressus burrows. We discuss the ecosystem engineering abilities of this species in relation to other crayfish and suggest future avenues of research to elucidate this species’ natural and life history.

Phytoplankton and zooplankton diversity in rural wetlands of Anand and Kheda districts, Gujarat India

Plankton diversity plays an essential role in aquatic wetlands. Phytoplankton and zooplankton communities were assessed in three permanent water bodies: Petli (S1), Deva (S2) and Heranj (S3) of the Anand and Kheda districts. Sampling was done from December 2020 to March 2021. Collection of plankton and identification of planktons was done using various published plankton manuals. A total of 32 phytoplankton have been recorded during the study period, from which 36 % belong to class Chlorophyta, 32 % belong to class Bacillariophyta, 16 % belong to Cyanophyta, 10 % belong to Charophyte, 3 % belong to Dinophyta, and 3 % belong to Euglenophyta. In addition, a total of 27 zooplankton species have been found, from which 46 % belong to Maxillopoda, 23 % belong to Monogononta, 19 % belong to Branchiopoda, 8 % belong to Eurotatoria, and 4 % belong to Hexanauplia. S1 has the maximum number of phytoplankton (24), followed by S3 with 18 and S2 with 15 species. Zooplankton were at the maximum in S1 (19), followed by S2 with 16, and S3 with 11 species. Results of the present study indicate that the studied wetlands have rich plankton diversity.

Stratigraphic and Paleoecological Significance of the Early/Middle Pleistocene Vertebrate Fauna of the Süttő 21 Site

The Süttő 21 site is a fissure fill of the freshwater limestone of the Gazda quarry in Süttő. The material was collected between 2017 and 2019, and the results are summarised in this article, with a special focus on the small vertebrate fauna of the site and its stratigraphic and paleoecological significance. The fissure fill can be placed around the Early/Middle Pleistocene boundary (ca. 1.1 and 0.77 Ma). The paleoecological analysis of the herpeto- and mammal fauna of the sequence indicates the proximity of a permanent water body. The lower part of the sequence is dominated by open habitat indicator taxa indicating a cool, dry climate. Towards the upper part of the sequence, the climate remained cool, but became wetter, and the vegetation gradually changed to forest-steppe/open forest. The fauna of the Süttő 21 site can be compared with the material of sites that are of a similar age, thus revealing taxonomic and paleoecological differences between different areas of the country. While a warm, dry climate and open vegetation can be reconstructed in the Villány Hills around the Early/Middle Pleistocene boundary, the Northern Hungarian areas had a cooler, wetter climate and a slightly more closed (sparse forest, forest-steppe) vegetation during this period.

A new species of Acanthocyclops Kiefer, 1927 (Copepoda, Cyclopoida) from ephemeral and permanent waterbodies of Sian Ka’an and Calakmul biosphere reserves, Mexico

Abstract A new species of the genus Acanthocyclops is described from temporal freshwater bodies in the Sian Ka’an and Calakmul Biosphere Reserves in Southeast Mexico. Acanthocyclops fiersi n. sp. represents the third species of the genus described from the Neotropics, only after A. rebecae and A. smithae. Acanthocyclops fiersi n. sp., is recognized as a member of the A. vernalis-robustus species-complex, and its clear divergence with respect to its congeners was supported using comparative morphology and molecular methods. The mtCOI marker revealed a 0.54% K2P divergence within populations of A. fiersi n. sp. and 17.6-22.41% with respect to other members of the A. vernalis-robustus species-complex. Acanthocyclops fiersi n. sp. might be restricted to the Yucatán Peninsula. Comments about the likely underestimated regional diversity of Acanthocyclops and the need of further studies in the Neotropics are provided. An identification key to the species of Acanthocyclops distributed in Mexico is included.

Detection, occupancy, and abundance of the alligator snapping turtle in Texas

AbstractThe alligator snapping turtle (Macrochelys temminckii) is a long‐lived species that is widely distributed across the southeastern United States. Both these characteristics make monitoring its occupancy and abundance particularly challenging. In 2020 and 2021, we conducted hoop trap surveys at 51 permanent water bodies across the Texas, USA, range of the species to estimate occupancy and average abundance with site occupancy models and multinomial N‐mixture models, respectively. We confirmed the species to be present at 61% of surveyed locations. Mean detection probability was 0.77, and was influenced methodologically by the spacing of traps, and environmentally by lunar phase and water flow velocity. Mean occupancy probability was 0.82, and mean estimated abundance was 7.57 turtles/site. Our data provided evidence that the species has a higher occurrence probability in waters of highly forested catchments, and is most probable to occur in highest abundances at median latitudes within its Texas range. Despite known microhabitat preferences of the species, instream habitat characteristics (e.g., canopy coverage, depth, sinuosity) did not strongly influence its occupancy or abundance. Spatial dynamics of the occupancy and abundance of the species in Texas are influenced by landscape features more than local habitat. These results further corroborate the importance of watershed land cover to aquatic organisms, and our methods provide a standardized template for monitoring and quantifying important demographic parameters of the species across multiple locations while accounting for imperfect detection.

Chironomidae in shallow water bodies of a protected lowland freshwater floodplain ecosystem.

Lowland floodplains are complex ecosystems comprised of standing and flowing waters interacting with terrestrial habitats, and the main force creating, shaping and influencing, both habitats and biotic communities, is a hydrological regime and water supply from the parent river. In areas not much altered by anthropogenic influence, the Danube creates such floodplain areas, and temporary shallow water bodies within represent biodiversity important habitats. In the Kopački Rit Nature Park floodplain in Croatia, diversity based on Chironomidae (Diptera) in both benthic and epiphytic communities was studied in eight ponds (temporary shallow water body) and at two channel locations (permanent shallow water body). At each location samples of sediment and macrophytes were taken at three sites. The benthic chironomid community was comprised of 29 taxa, most abundant being representatives of the Chironomus genus and Tanypus kraatzi in ponds, and Polypedilum nubeculosum and Cladotanytarsus sp. in channel samples. Cricotopus gr. sylvestris, Paratanytarsus sp. and Endochironomus tendens were dominant epiphytic chironomids (18 taxa). Non-metric multidimensional scaling and analysis of similarity analyses showed there was a clear grouping of sampling locations based on their position in the park and the distance from each other, more evident in the case of benthic chironomid communities. Furthermore, when the water bodies were compared based on the community structure from different locations and substrates, there was also a statistically significant separation. Community composition indicates high productivity and organic matter production of studied water bodies, but moreover, the differences in substrate preferences evident in 16 common out of 31 recorded chironomid taxa, indicate the importance of habitat complexity preservation in a floodplain.

A dataset of the annual water bodies in wet seasons on the Mongolian Plateau during 1990–2021

The Mongolian Plateau is characteristic of fragile ecosystem and serious land desertification. As one of the main climate-varied sensitive regions in Asia, it is of great value for the study on temporal and spatial changes of water resources. For the production of this dataset, we used Google Earth engine (GEE) platform to process the high–quality Landsat series satellite images available in the past 32 years (1990–2021). Using the minimum cloud amount synthesis algorithm, we obtained the minimum cloud amount images in the wet season (from June to September) of each year. After calculating NDWI, we further used the OTSU algorithm for threshold segmentation, and extracted the yearly water body data with 30m resolution on the Mongolian Plateau in the wet season for 32 years. The final data results are saved in GeoTIFF format. Through comparison, the average consistency between this dataset and the JRC annual water body data in both permanent water body and maximum water body is 93.0% and 90.9% respectively, which indicates the high reliability of this dataset. The dataset can provide data support for water resource changes, ecological construction planning, environmental protection, etc. on the Mongolian Plateau.

Long-Term Changes in Water Body Area Dynamic and Driving Factors in the Middle-Lower Yangtze Plain Based on Multi-Source Remote Sensing Data

The accurate monitoring of long-term spatial and temporal changes in open-surface water bodies offers important guidance for water resource security and management. In the middle and lower reaches of the Yangtze River, the monitoring of water body changes is especially critical due to the dense population and drastic climate change. Due to the complexity of the physical environment in which the water bodies are located, the advantages and disadvantages of various water body detection rules can vary in large-scale areas. In this paper, we use Landsat 5/7/8 data to extract the area of water bodies in the study area and analyze their spatial and temporal trends from 1984 to 2020 using the Google Earth Engine (GEE) platform. We propose an improved water body extraction rule based on an existing multi-indicator water body algorithm that combines impervious surface data and digital elevation model data. In this study, the performance of the improved algorithm was cross-validated using seven other water body indicator algorithms, and the results showed the following: (1) the rule accurately retained information about the water body while minimizing the interference of shadows on the extracted water body. (2) On the annual scale from 1984 to 2020, the open-surface water body dataset extracted using this improved rule showed that the turning point for the area of each water body type was 2011, with an overall decreasing trend in area before 2011 and an increasing trend in area after 2011, with the exception of special years, such as 1998. (3) The driving mechanism analysis showed that, overall, precipitation was positively correlated with the water body area and temperature was negatively correlated with the water body area. Additionally, human activities can have an impact on surface water dynamics. The key influencing factors are diverse for each water body type; it was found that seasonal water bodies were correlated with precipitation and paddy fields and permanent water bodies were correlated with temperature and urban construction. The accurate monitoring of the spatial and temporal dynamics of open-surface water performed in this study can shed light on the sustainable development of water resources and the environment.

Can germination strategies help to understand regional co‐occurrence of two morphologically conserved congeneric macrophytes?

Abstract In variable environments the production of dormant life stages can help organisms to avoid periods that are unsuitable for growth and reproduction, and different species may rely on different cues to break dormancy. However, it is still unclear to what extent variation in germination strategies can help to explain variation in the distributions of related species and contribute to adaptive radiation. Using standardised laboratory germination trials, we demonstrated the existence of both inter‐ and intraspecific variation in germination strategies in two congeneric species of submerged macrophytes that occur in a dynamic wetland system characterised by strong variation in salinity and hydro‐regime. The ditch grass Ruppia maritima L. typically lives in temporary waterbodies, where it assures high seed set through a short life cycle, early flowering and self‐pollination. Its congeneric Ruppia spiralis L. ex Dumortier grows in (semi‐)permanent waterbodies where it can have a perennial life cycle. Populations are presumed to be maintained mainly through clonal growth, and seed production is lower than in R. maritima. We hypothesised that salt and temperature are two important germination cues in these ecosystems that can explain the observed differences in distribution patterns between these two species. We exposed seeds of both species in a full factorial designed experiment to four different salinities (0‰, 7‰, 14‰ and 21‰) and two different temperature regimes (17 and 24°C, simulating spring and summer temperatures, respectively). The experiment was repeated over three consecutive inundation cycles (30 days of inundation, followed by 30 days of drought). During the third cycle, all seeds were inundated with fresh water, as salinity might constraint germination in species that rely on fresh water for germination. We found that the R. maritima seeds had overall low germination success. The freshwater inundation caused rapid germination in seeds that previously were in a high‐salinity treatment. In R. spiralis, which inhabits more permanent habitats of variable salinity, we detected a more complex response, involving two germination peaks. These two contrasting germination strategies observed within R. spiralis could target spring or summertime growing periods respectively. We believe that the observed variation in germination strategies is an important element in ecological differentiation in the morphologically conserved genus Ruppia and may have contributed to past and ongoing speciation.

Highland pastoralism in the Early Bronze Age Kura-Araxes cultural tradition: Stable oxygen (δ18O) and carbon (δ13C) isotope analyses of herd mobility at Köhne Shahar in northwestern Iran

Nomadic pastoralism and long-distance transhumance are often invoked as primary explanatory mechanisms for human migrations and regional interactions in the Early Bronze Age Kura-Araxes cultural tradition of the West Asian highlands. Based on established archaeological proxies of pastoralism, these arguments have rendered homogenous reconstructions of a complex pastoral landscape because of the effect of site formation processes that smooth out diagnostic archaeological signatures of diverse herd mobility strategies. Overcoming this equifinality requires an interdisciplinary approach that can empirically measure animal movements in the past. In this paper we use stable oxygen (δ18O) and carbon (δ13C) isotope analyses of incrementally-sampled teeth to investigate sheep, goat, and cattle herding strategies at the Kura-Araxes settlement of Köhne Shahar. Our δ18O analysis reveals that cattle and caprines accessed different water sources, with cattle staying closer to the settlement and the more permanent bodies of water that it provided. Restricted intra-annual ranges in δ13C values also show that nearly all herd animals were managed locally, involving limited transhumance that was supplemented with dry foddering. We contextualise our observations with published zooarchaeological data to call for more nuanced interpretations of Kura-Araxes pastoral landscapes that deemphasise the role of long-distance pastoral mobilities.

The Effect of Physico-Chemical Stress on the Population of Chlamydomonas Species in a permanent pond of Kanpur, (U.P.) India

In permanent lentic water bodies, the chemical picture completely depends on the surroundings from where these bodies receive effluents. Planktons play an important role as primary producers of the system. The limnological study is important for water quality monitoring by which correlation has been established among different physical, chemical, and biological parameters. This statistical analysis easily represented the presence /absence of Planktons on the basis of seasonal variations. Regarding the seasonal variations, the values of pH, magnesium & calcium (Mg, Ca), dissolved oxygen & dissolved oxygen matter (DO, DOM) indicate variation in water quality which directly or indirectly influence the population of Chlamydomonas elliptica, Chlamydomonas globosa, Chlamydomonas intermedia, and Chlamydomonas orbicularis. On the basis of chemical analysis in terms of DO & DOM, the shallow water system was moderately polluted. Chlamydomonas intermedia showed dominant species which occurred most of the months in a year. The fluctuation in the population densities of Chlamydomonas elliptica, Chlamydomonas globosa, and Chlamydomonas orbicularis was observed greatly as they occurred in a few months in a year. Chlamydomonas intermedia showed positive co-relation with DO and significant negative co-relation with DOM. Mg and pH showed significant negative values. Apart from this, biological populations also showed various co-relation among other known species.

Assessment of Mercury Concentrations in Water and Fish Tissue Analysis in Kaw Lake, Oklahoma, 2022

The Kaw Nation has been collecting water, sediment, and fish samples from Kaw Lake and upper Arkansas River from 2007 to present to examine the concentrations of Mercury and other heavy metals to protect the health of the tribal members. Kaw Lake is in the North-Central part of Oklahoma. Kaw Lake is a permanent water body constructed in 1976 by the Army of Corps of Engineers. The Lake is consistently fed by the Arkansas River and other tributaries as runoff coming all the way from Colorado through Kansas to Kaw Lake of Oklahoma. The Lake has a surface area of 26.64 square miles (69 km2) and shoreline of 168 miles (270 km) with a total drainage area of 56,345 square miles (145,393 km2) and an average water depth of 8 meters. The water and fish samples were collected from 7 sites of Kaw Lake, once in a month and the fish samples once in a year during summertime, early July to end of July. The fish samples focused on 5 sport, predator, and bottom dwelling species of large consumable size, greater than 200 mm length and 560 grams weight. The five fish sampled were Catfish, White bass, Largemouth and Smallmouth bass, Black and White crappie. The fish and water samples were sent to Accurate Environmental Labs for detailed analysis. Predator species were analyzed as fillet and the bottom dwellings as a whole fish using EPA Method 7471A-M. Mercury from Water and Fish Tissue Samples were analyzed by Atomic Fluorescence Spectrometry. The laboratory analysis indicated that all the Mercury concentration in the fish samples except in Blue Catfish and Spotted Bass fall below the Maximum Contaminant Level (MCL) of 0.5 mg/kg.

Multi-Scale Flood Mapping under Climate Change Scenarios in Hexagonal Discrete Global Grids

Among the most prevalent natural hazards, flooding has been threatening human lives and properties. Robust flood simulation is required for effective response and prevention. Machine learning is widely used in flood modeling due to its high performance and scalability. Nonetheless, data pre-processing of heterogeneous sources can be cumbersome, and traditional data processing and modeling have been limited to a single resolution. This study employed an Icosahedral Snyder Equal Area Aperture 3 Hexagonal Discrete Global Grid System (ISEA3H DGGS) as a scalable, standard spatial framework for computation, integration, and analysis of multi-source geospatial data. We managed to incorporate external machine learning algorithms with a DGGS-based data framework, and project future flood risks under multiple climate change scenarios for southern New Brunswick, Canada. A total of 32 explanatory factors including topographical, hydrological, geomorphic, meteorological, and anthropogenic were investigated. Results showed that low elevation and proximity to permanent waterbodies were primary factors of flooding events, and rising spring temperatures can increase flood risk. Flooding extent was predicted to occupy 135–203% of the 2019 flood area, one of the most recent major flooding events, by the year 2100. Our results assisted in understanding the potential impact of climate change on flood risk, and indicated the feasibility of DGGS as the standard data fabric for heterogeneous data integration and incorporated in multi-scale data mining.

The northernmost Eurasian Miocene beavers: Euroxenomys (Castoridae, Mammalia) from Olkhon Island, Lake Baikal (Eastern Siberia)

The castorid dental material described in this paper derives from Miocene, fossiliferous deposits of the Baikal rift valley, exposed at Tagay Bay on Olkhon Island in the Lake Baikal, in eastern Siberia. It consists of maxillary fragments and isolated upper and lower teeth of the small trogontheriine beaver Euroxenomys minutus (von Meyer, 1838). It is the first record of the species in Asia and at the same time the northernmost occurrence of Eurasian Miocene beavers. The magnetostratigraphic correlation of the Tagay -1 section, indicates a late Burdigalian, Early/early Middle Miocene age of ~16.5 to ~16.3 Ma that corresponds to the Mammalian Neogene zone MN4/5. The presence of E. minutus in Tagay is an indicator for an Orleanian European-Siberian bioprovince during the Mid-Miocene Climate Optimum, and for a continuous belt of humid, warm-temperate to subtropical forests, stretching from Europe to Siberia, and probably further to East and South-Eastern Asia. In Eurasia, beaver remains are an indicator of permanent water bodies, which is in agreement with the palaeoenvironment of the Tagay locality.

Estimativa da área afetada por inundações através de polarimetria com imagens Sentinel 1A Synthetic Aperture Radar (SAR) na bacia do rio Frío (Costa Rica)

Synthetic Aperture Radar (SAR) polarimetry is a remote sensing technique known for being applied to monitoring of land surface and water bodies. Polarimetry aims at charactering the land surface through the analysis of its response under different combinations of transmitting and receiving an- tennas polarization, called polarimetric channels. The use of cross-polarization (vertical/horizontal) proved to be efficient for estimating the extent of the floods between July 22nd and July 30th in the Frío river basin (Costa Rica). To that end, Sentinel-1 images from the European Space Agency have been used, with a workflow process and RGB composition that allowed to draw a clear distinction between flooded and permanent water bodies. The use of optical imagery for flood mapping is limit- ed by weather conditions, specially by the presence of clouds. SAR measurements are independent of daytime and weather conditions, providing valuable information for monitoring flood events. Furthermore, flood extent is a critical factor for the calibration and validation of hydraulic models (Horritt, 2006). Flood extent can be also used for damage assessment and risk management and can be of benefit to rescuers during flooding (Corbley, 1999).

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.