Temporary Water Bodies Research Articles

Community Characteristics of Sympatric Freshwater Turtles from Savannah Waterbodies in Ghana

Despite increasing pressures on freshwater resources worldwide, and the threatened status of most freshwater turtles, there is still limited knowledge of habitat use and niche partitioning in Afrotropical freshwater turtle communities. In this study, we describe habitat associations, community diversity, and temporal patterns of occurrence of freshwater turtle species in the Dahomey Gap ecoregion of Ghana (West Africa). We gathered data from 13 sites in central Ghana and along the Sene Arm of Lake Volta in the Digya National Park (Bono East Region). We employed opportunistic short-term surveys (at seven sites) together with longer-term (six-months duration) standardized evaluations of turtle presence and numbers in different habitats (at six sites). Overall, a total of 210 turtle individuals of four species (Trionyx triunguis, Cyclanorbis senegalensis, Pelomedusa sp. and Pelusios castaneus) were recorded; precise capture sites and habitat type were recorded for 139 individuals, but the 71 individuals observed in marketplaces were not considered in our analyses. At a local scale, we observed three sympatric species in various study sites. In each of these sites, the dominant species was either C. senegalensis or Pelomedusa sp., with the latter species being more abundant in temporary waterbodies and C. senegalensis more numerous in permanent ones. A Multiple Correspondence Analysis suggested that, in permanent waterbodies all species were associated with similar physical habitat variables. In a Canonical Correspondence Analysis, we showed that the density of herbaceous emergent vegetation was more important for P. castaneus than for C. senegalensis. Comparisons of diversity metrics between our study sites and previous studies revealed that turtle community composition was similar across savannah sites.

The effect of larval cigarette exposure on the life history of the major malaria vector Anopheles arabiensis (Diptera: Culicidae)

Anopheles arabiensis typically breeds in clean, temporary bodies of water. This species, however, is adapting to breeding in polluted water. This has the effect of pollutants being non-insecticidal forms of selection pressure driving insecticide resistance. Cigarette butts are common plastic pollutants which are complex toxicants that would include nicotine pollutants. This is of concern as the neonicotinoid clothianidin is suggested as a potential vector control insecticide. As such, there is a risk that larval exposure to cigarette pollution could alter the efficacy of this insecticide. This study aimed to examine the effect of larval cigarette exposure on the life history of laboratory-reared An. arabiensis, as well as elucidate the role of nicotine in these effects. Two laboratory strains of An. arabiensis were used, the insecticide susceptible SENN and the resistant SENN-DDT strain. The effects of cigarette and nicotine exposure on key life history traits were assessed. SENN-DDT laid more eggs in cigarette-polluted water than SENN but developed significantly slower in polluted water. Larval cigarette selection increased adult longevity in SENN-DDT, but reduced longevity in SENN. Larval selection did not alter neonicotinoid tolerance in males of either strain, or female SENN. Nicotine selection increased tolerance to both neonicotinoids, but cigarette selection only increased clothianidin tolerance in SENN-DDT females. Insecticide resistant An. arabiensis therefore had an advantage in cigarette polluted environments. Selection for cigarette tolerance only increased neonicotinoid tolerance where insecticide resistance was already present. Therefore, larval cigarette exposure may only have a limited effect on neonicotinoid efficacy for malaria control.

First evidence of underwater sounds emitted by the living fossils Lepidurus lubbocki and Triops cancriformis (Branchiopoda: Notostraca)

Sound is the most effective means of communication in marine and freshwater ecosystems. However, no data about acoustic emissions from non-malacostracan crustaceans are currently available, so their ability to produce sounds is unknown. For the first time, this study investigated the sound produced by 2 tadpole shrimp species,Triops cancriformisandLepidurus lubbocki.L. lubbockiindividuals were collected from a natural temporary pond in Sicily (Italy), whereasT. cancriformisindividuals were obtained from eggs contained in sediment from a rock pool in Sardinia (Italy). In the laboratory, experimental tanks with the animals (one species at a time) were acoustically monitored. Both species produced high-frequency, wideband pulses distinguishable by their sound pressure level, which was higher inL. lubbocki(146 dB) than inT. cancriformis(130 dB), and by their first and second peak frequencies, which were higher inL. lubbocki(65 and 86 kHz) than inT. cancriformis(63 and 71 kHz). The energy distributions in the power density spectra showed different shapes, as revealed by the 3 dB bandwidth and centre frequency. The pulse durations were 88 and 97 µs inL. lubbockiandT. cancriformis, respectively.L. lubbockipresented a higher emission rate thanT. cancriformisand a marked circadian pattern, with a higher abundance of sounds during the night. This study reports the first evidence of sound emissions from non-malacostracan crustaceans and reveals the high potential of passive acoustic monitoring to detect the presence, abundance, and life cycle of these elusive keystone species of temporary water bodies.

Seasonal Diversity of mosquito species in Dakshina Kannada district, Karnataka, India.

Dakshina Kannada is one of the districts of Karnataka state of India with high incidences of mosquito-borne diseases, especially malaria and dengue. The larval stages of the mosquitoes are very important in determining the prevalence of adult mosquitoes and associated diseases. Hence, the occurrence of mosquito species was investigated by sampling different water bodies present in the Dakshina Kannada district from June 2014 to May 2017. Random sampling was carried out from permanent and temporary, artificial and natural water bodies belonging to 11 types of microhabitats using dippers and suction pumps. A maximum of 37 mosquito species belonging to 12 genera were recorded with the dominant genera being Culex. Most species have been recorded from temporary bodies of water with the highest number of species in receptacles. Monsoon is the most productive season, both in terms of occurrence and abundance followed by post-monsoon and pre-monsoon. The abundance of mosquito larvae was significantly higher in temporary water bodies compared to the permanent. Abundant rainfall in the study area which produces many natural and domestic temporary water bodies accounts for mosquito breeding throughout the year.

Feeding ecology and coexistence dynamics in a community of fishes in a temperate temporary water body

AbstractTemporary water bodies are temporally variable ecosystems supported primarily by rainwater. The biota supported by such water bodies present a range of capacities to remain in this environment for all or part of their life cycles. During floods, temporary pools can connect with permanent streams, promoting changes in trophic networks in the aquatic food webs. The aim of this research was to analyse the feeding ecology of a fish community in a temporary pool near of Tlacotalpan, in the Mexican southeast, in order to understand the dynamics of the feeding habits. First, we identified feeding habits that can be interpreted as guilds of the fishes in the temporary pool: the annual killifish Millerichthys robustus (the only autochthonous species) is planktophagous; Cynodonichthys tenuis and Astyanax aeneus are insectivores; Dormitator maculatus and larvae of amphibians (Lithobates sp.) are mainly detritivorous; and Poecilia mexicana is planktophagous and insectivorous. We then estimated the effect of coexistence on niche breadth and overlap. The niches of M. robustus and P. mexicana evidenced overlap, but the breadth was adjusted inversely, suggesting feeding specialisation in M. robustus in response to competition. We documented the existence of two cohorts of M. robustus; the niche breadth of the first and second cohorts suggesting different strategies probably related to competition under variable conditions. The niche of C. tenuis and A. aeneus, and D. maculatus and tadpoles overlapped, following a pattern of feeding generalisation in response to competition.

Fatty acid stable isotopes add clarity, but also complexity, to tracing energy pathways in aquatic food webs.

Tracing the flow of dietary energy sources, especially in systems with a high degree of omnivory, is an ongoing challenge in ecology. In aquatic systems, one of the persistent challenges is in differentiating between autochthonous and allochthonous energy sources to top consumers. Bulk carbon stable isotope values of aquatic and terrestrial prey often overlap, making it difficult to delineate dietary energy pathways in food webs with high allochthonous prey subsidies, such as in many northern temperate waterbodies. We conducted a feeding experiment to explore how fatty acid stable isotopes may overcome the challenge of partitioning autochthonous and allochthonous energy pathways in aquatic consumers. We fed hatchery‐reared Arctic Char (Salvelinus alpinus) diets of either benthic invertebrates, terrestrial earthworms, or a mixture of both. We then compared how the stable carbon isotopes of fatty acids (δ13CFA) distinguished between diet items and respective treatments in S. alpinus liver and muscle tissues, relative to bulk stable isotopes and fatty acid profiles. Although a high degree of variability of fatty acid stable carbon isotope values was present in all three measures, our results suggest that the ability of this method to overcome the challenges of bulk stable isotopes may be overstated. Finally, our study highlights the importance of further experimental investigation, and consideration of physiological and biochemical processes when employing this emerging method.

Zwergschnepfe (Lymnocryptes minimus) Winterliche Vorkommen in Maßnahmenflächen für den Kiebitz

As part of the restoration of extensive, grazed wet grassland with open, temporary shallow water bodies for the lapwing, habitat conditions were created in seven areas of Baden-Württemberg that also meet the habitat requirements of wintering Jack Snipes. Four of the seven areas were specifically checked for the presence of the species on 11/01/2024. A total of five Jack Snipes were detected in three of the areas. This means that there are now winter records of the Jack Snipe from all seven sites. When additional data are taken into account, the sum of the maxima of the Jack Snipe, from all areas, amounts to a total of 37 individuals. In terms of nature conservation, this number would be classified as being of at least supraregional to state-wide importance, while the individual areas would be classified as being of regional importance. The data show that the wintering population of the Jack Snipe can be supported with a high degree of predictability if suitable habitat development measures are implemented. From a nature conservation perspec- tive, these important occurrences are proof that measures implemented for the lapwing have a relevant positive effect not only for this target species itself, but also for other declining species.

Late Cretaceous palynomorphs from the Golfo San Jorge Basin, Argentina

A lithofacial and palynological study was carried out on the Cañadón Seco Formation in the La Frieda Oeste x-1 well (Golfo San Jorge Basin). According to sedimentological characteristics of the core four main litofacies lithofacies are defined: 1. Cross-bedded sandstones, 2. Interlaminated fine-grained sandstones and mudstones, 3. Shales, and 4. Muddy tuff. The cross-bedded sandstones correspond to channel deposits, which are interpreted as lateral bars (point bars) or attached bars. The interchannel area is dominated by interlaminated fine-grained sandstones and mudstones, together with shales. The former represents sedimentation occurred in proximal floodplain areas, while shales correspond to deposition in distal floodplains, where thin and scarce muddy tuff intercalations indicate ash fall events. The palynological assemblage here analyzed was recovered from the green shales corresponding to distal floodplains areas, probably surrounding temporary water bodies. The floristic assemblage contains abundant fern spores as a dominant group, followed by angiosperm and gymnosperm pollen grains. Bryophyte and lycophyte spores, along with fungal remains, are also present in lower proportions. Based on the taxonomic content of the palynoflora, a Turonian–Coniacian age is suggested for this assemblage. Additionally, some taxa present in the assemblage allow inferring temperate to warm and humid conditions. This new record represents a period of time little known for the evolution of angiosperms in the southern region of Gondwana.

Zwergschnepfe (Lymnocryptes minimus) Winterliche Vorkommen in Maßnahmenflächen für den Kiebitz.

As part of the restoration of extensive, grazed wet grassland with open, temporary shallow water bodies for the lapwing, habitat conditions were created in seven areas of Baden-Württemberg that also meet the habitat requirements of wintering Jack Snipes. Four of the seven areas were specifically checked for the presence of the species on 11/01/2024. A total of five Jack Snipes were detected in three of the areas. This means that there are now winter records of the Jack Snipe from all seven sites. When additional data are taken into account, the sum of the maxima of the Jack Snipe, from all areas, amounts to a total of 37 individuals. In terms of nature conservation, this number would be classified as being of at least supraregional to state-wide importance, while the individual areas would be classified as being of regional importance. The data show that the wintering population of the Jack Snipe can be supported with a high degree of predictability if suitable habitat development measures are implemented. From a nature conservation perspec- tive, these important occurrences are proof that measures implemented for the lapwing have a relevant positive effect not only for this target species itself, but also for other declining species.

On the Biodiversity Hotspot of Large Branchiopods (Crustacea, Branchiopoda) in the Central Paroo in Semi-Arid Australia

Biodiversity is central to the structure and functioning of communities including those of temporary water bodies. Worldwide the large branchiopod component commonly consists up to about six species instantaneously per site and twice that number across the surrounding district. Where these figures reach eight to ten species per site and about twice that number per district, the term diversity hotspot is sometimes used. In eastern Australia, biogeographical factors have facilitated a rich large branchiopod fauna ca 80 species and locally within 500 km2 of the central Paroo in northwestern New South Wales where a rarely diverse and abundant array of habitats supports at least 38 species, though the maximum per site syntopically is still near 10 species — we suggest it be termed a super hotspot.

RAISING EXPERIMENTAL INFECTION OF PARAMPHISTOMOSIS IN SHEEP UNDER LABORATORY CONDITION

Snails, the intermediate host are the transmitter of trematode infection in ruminants in the endemic areas of Punjab. Under DST-SERC-FAST-Track project(DST, GOI, New Delhi), the survey was conducted mainly in ponds, bank of the River Satluj and Beas its surrounding temporary water bodies, ditches, impoundments, near by tube well sand paddy fields in Ludhiana, Hoshiarpur Kapurthala and Amritsar district of Punjab. A total of 701 snails were collected, and seven species were identified as Indoplanorbis exustus, Gyraulus convexiusculus, Lymnaealuteola, L. auricularia, Bellamya (Vivipara) bengalensis, Corbicula striatella, and Thiara tuberculata. Out of the total collected snails, 365, 4, 165, 127, 16 and 24 were contributed by I. exustus, G. convexiusculus, Lymnaeasp., B. bengalensis, C. striatella and T. tuberculata respectively. Snails like I. exustus, G. convexiusculus and Lymnaeasp were found to be most prominent in ditches, impoundments, nearby tube wells and paddy fields which play a very important role in the transmission of most pathogenic diseases like paramphistomosis and schistosomosis in ruminants respectively. The other snails were recorded to be common in bank of the River Satluj and its surrounding temporary water bodies. I. exustusan intermediate host of Paramphistomum spp. were kept in different batches individually in glass tubes as per Leiper's glass tube technique. Snails in bulk were also kept in beaker, surgical tray, earthenpots and petridishes with coloured poly then estrips to harvest metacercariae. Polythene strips of different colour, green, yellow and pink were used for the encystment of cercariae. These strips were stuck to the inner surface of the petridishes, beakers and surgical tray. Various encystment materials like water plants; lettuce and itsit (Trienthemagovinda) leaves were used. It was observed that maximum attraction of cercariae was towards itsit leaves followed by green and yellow polythene strips. Very few cercariae were also encysted onthe wall of the containers. 185 individuals of I. exustuswere found to be shedding cercariae with the prevalence rate of 55.89%. The cercariae were identified ascerearia of Paramphistomum epiclitum. The collected metacercariae were used for raising the infection in sheep. A total of 12,040 metacercariae was collected from185 infected snails (I. exustus) and kept in polyvinyl tubes (stored at 4°C). These metacercariae were given orally to two sheep for raising paramphistome infection under experimental condition. The animals were subjected with 4000 metacercariae to each sheep. The grass with encysted metacercariae was also collected from thefields for feeding to sheep. Faecal samples examined microscopically and found positive for paramphistome eggs after 135 days post infection. The experiments confirm the transmission of paramphistome infection in sheep. This disease is highly pathogenic and there is a need to formulate control and preventive measures for the betterment of livestock industry

Is the spread of the alien water boatman Trichocorixa verticalis verticalis (Hemiptera, Corixidae) aided by zoochory and drought resistant eggs?

Abstract Desiccation resistance is a key trait determining the distribution of aquatic insects, their potential for overland dispersal, and survival during drought periods in temporary waterbodies, as well as the spread of invasive species. Passive dispersal by waterbirds is considered to be a key process favouring the spread of invasive species and is more likely to occur for insects with eggs that are resistant to desiccation or gut passage. We investigated the hypothesis that the eggs of the alien boatman Trichocorixa verticalis verticalis are resistant to desiccation and digestion and thus able to disperse via waterbirds. We conducted experiments to test for egg resistance to desiccation in still air and under moving air conditions, to simulate bird flight. Oviposition on greater flamingo (Phoenicopterus roseus) legs and wetland plants was tested in the laboratory and in the field. Resistance of eggs to simulated gut passage was studied, as was the viability of eggs recovered from Eurasian coot (Fulica atra) droppings in the field. Only a fraction of eggs hatched after 8 hr of exposure to still air at 15°C (4% of exposed eggs), and after 2 hr exposure to air flow conditions at 20°C (8%). Oviposition on flamingo legs was confirmed in the laboratory but not in the field. However, oviposition rates were higher on plant stems than on flamingo legs. Digestion simulations showed very low resistance to chemical treatment and no resistance to scarification, and eggs recovered from coot droppings did not hatch. Our experiments demonstrated that T. v. verticalis cannot be considered to have eggs resistant to desiccation or gut passage. However, the dispersal of eggs on legs of flamingos or other waterbirds may occur as rare events. This epizoochory of eggs could potentially contribute to the expansion and gene flow of T. v. verticalis around the Mediterranean region.

First record of <em>Arctodiaptomus wierzejskii</em> (Richard, 1888) (Copepoda Calanoida Diaptomidae) from Malta

Diaptomid copepods belonging to the genus Arctodiaptomus Kiefer, 1932 were collected in two temporary water bodies in Malta. The morphological identification of the collected specimens proved that they belong to Arctodiaptomus wierzejskii (Richard, 1888) even if a morphological peculiarity pertaining to the morphology of the male right antennule of the Maltese populations was observed and here briefly discussed. This finding constitutes the first record of a calanoid copepod from the inland waters of the Maltese Islands.

Combining Multi-Sensor Satellite Imagery to Improve Long-Term Monitoring of Temporary Surface Water Bodies in the Senegal River Floodplain

Accurate monitoring of surface water bodies is essential in numerous hydrological and agricultural applications. Combining imagery from multiple sensors can improve long-term monitoring; however, the benefits derived from each sensor and the methods to automate long-term water mapping must be better understood across varying periods and in heterogeneous water environments. All available observations from Landsat 7, Landsat 8, Sentinel-2 and MODIS over 1999–2019 are processed in Google Earth Engines to evaluate and compare the benefits of single and multi-sensor approaches in long-term water monitoring of temporary water bodies, against extensive ground truth data from the Senegal River floodplain. Otsu automatic thresholding is compared with default thresholds and site-specific calibrated thresholds to improve Modified Normalized Difference Water Index (MNDWI) classification accuracy. Otsu thresholding leads to the lowest Root Mean Squared Error (RMSE) and high overall accuracies on selected Sentinel-2 and Landsat 8 images, but performance declines when applied to long-term monitoring compared to default or site-specific thresholds. On MODIS imagery, calibrated thresholds are crucial to improve classification in heterogeneous water environments, and results highlight excellent accuracies even in small (19 km2) water bodies despite the 500 m spatial resolution. Over 1999–2019, MODIS observations reduce average daily RMSE by 48% compared to the full Landsat 7 and 8 archive and by 51% compared to the published Global Surface Water datasets. Results reveal the need to integrate coarser MODIS observations in regional and global long-term surface water datasets, to accurately capture flood dynamics, overlooked by the full Landsat time series before 2013. From 2013, the Landsat 7 and Landsat 8 constellation becomes sufficient, and integrating MODIS observations degrades performance marginally. Combining Landsat and Sentinel-2 yields modest improvements after 2015. These results have important implications to guide the development of multi-sensor products and for applications across large wetlands and floodplains.

Effect of Hydrological Connectivity on the Phosphorus Buffering Capacity of an Urban Floodplain

Floodplains can perform nutrient buffering functions and therefore influence the riverine nutrient dynamics depending on the extent of the hydrological connectivity. This work focused on quantifying the adsorption/desorption potential of a degraded floodplain of the Danube River (Lower Lobau) based on sediment characterization (grain size distribution, organic content, and P-fractions) and sediment type-specific P-adsorption via batch experiments. We established an adsorption/desorption budget model with a high temporal and spatial resolution. With this model, we identified spatial patterns related to hydrology and calculated the phosphorus buffering capacity of permanent and temporary floodplain water bodies. Sediment characteristics were defined by the distance to the inflow area and the hydrological connectivity of the floodplain water bodies. The main factor for the concentration of total phosphorus (Ptot) in the sediments was the grain size distribution. Ptot was ten times higher in silt-dominated sediments compared to gravel-dominated sediments. Inorganic phosphorus (Pinorg) ranged between 36 and 90% depending on the organic content of the sediments. Both the adsorption and the desorption potential of SRP (soluble reactive phosphorus) were highest in large, frequently connected water bodies and were strongly controlled by hydrology. The total adsorption potential of the floodplain was up to 40 times higher in wet years (e.g., 2002) than in dry years (e.g., 2003), when floodplain water bodies were connected less frequently to the main channel of the Danube. Up to 75% of the adsorbed SRP was desorbed and released into the water column after periods of connection. Consequently, SRP adsorption directly reduced the P-load in the Danube River main channel. The adsorption/desorption mechanisms worked as a buffering system by taking up the SRP imported during floods and releasing it over a longer period after the floods. This stimulated high primary production in the floodplain water bodies and impacted the overall P-retention of the floodplain.

Phylogeny and Biogeography of Spinicaudata (Crustacea: Branchiopoda).

Spinicaudata (spiny clam shrimp) is a taxon of Branchiopoda occurring since the Devonian and today it occurs nearly globally in temporary water bodies. We present the most species-rich phylogenetic analyses of this taxon based on four molecular loci: COI, 16S rRNA, EF1α and 28S rRNA. Our results support previous findings that Cyzicidae sensu lato is paraphyletic. To render Cyzicidae monophyletic we establish a fourth extant spinicaudatan family to accommodate Eocyzicus. Within Cyzicidae, none of the genera Cyzicus, Caenestheria or Caenestheriella are monophyletic, and the morphological characters used to define these genera (condyle length and rostrum shape) are not associated with well-delimited clades within Cyzicidae. There is insufficient resolution to elucidate the relationships within Leptestheriidae. However, there is sufficient evidence to show that the leptestheriid genera Eoleptestheria and Leptestheria are non-monophyletic, and there is no support for the genus Leptestheriella. Molecular clock analyses suggest that the wide geographic distribution of many spinicaudatan taxa across multiple continents is largely based on vicariance associated with the break-up of Pangea and Gondwana. Trans-oceanic dispersal has occurred in some taxa (e.g., Eulimnadia and within Leptestheriidae) but has been relatively rare. Our results highlight the need to revise the taxonomy of Cyzicidae and Leptestheriidae and provide evidence that the global spinicaudatan diversity may be underestimated due to the presence of numerous cryptic species. We establish Eocyzicidae fam. nov. to accommodate the genus Eocyzicus. Consequently, Cyzicidae comprises only two genera -Cyzicus and Ozestheria. Ozestheria occurs also in Africa and Asia and Ozestheria pilosa new comb. is assigned to this genus.

The current state of macrozoobenthos of some small reservoirs the North Kazakhstan region

Awareness of ecosystem integrity increases the relevance of collecting information on the biodiversity of water bodies of various types. The episodic nature of studies of small water bodies, along with the high variability of their hydrological, hydrochemical, and morphometric parameters, is the reason for the lack of a full assessment of the state of biota. The current paper provides information on macrozoobenthos of four small water bodies in the North Kazakhstan region. The study revealed 59 representatives with a predominance of insects in the benthofauna. Bottom complexes of shallow temporary water bodies were characterized by a wider spectrum with a greater proportion of insects relative to similar variables for lake Big Koskol. The basis was composed by species adapted to fluctuations of water availability, which led to a relatively stable state of biocenoses against the background of a significant range of quantitative characteristics of zoobenthos. More abundant development of benthic invertebrates highlighted in the lake Bolshoy Koskol (with the dominance of amphipods) and in the temporary water body T26 (with the predominance of insects). By the size of the average annual zoobenthos biomass — 29–31.5 g / m2 — the mentioned above water bodies were classified as highly productive. The level of development of benthic organisms in water bodies T20–T14, where Vermes were the leaders in biomass assessed as increased productive and moderate productive (10.3–3.1 g/m2 respectively). A low faunistic similarity of macrozoobenthos was noted, indicating the originality of the benthic complexes of the studied water body, which once again emphasizes the role of small water body in maintaining the biodiversity of the ecosystem. Relatively high structural variables of benthocenoses indicate a stable ecological state of bottom communities. The abundance of zoobenthos creates the prerequisites for the utilization of the studied and similar water bodies for organizing amateur — sport fishery and the extraction of feed used in aquarium fish farming

THE AVIFAUNA OF MARSH BIRDS IN THE RESERVOIRS OF THE KARATAU MOUNTAIN SYSTEM

The Karatau mountain range is a low-mountain system, does not have natural water sources in the form of lakes. Artificial water objects – water reservoirs – are the only large water bodies where most species of water birds are often found or locating during migration. One of the strategic important water bodies for agriculture of the Karatau mountain range is the Koskorgan reservoir. In addition, the Syrdarya River, one of the largest rivers in Kazakhstan, is the most important waterway in the researched region. During the spring flood of the river, temporary water bodies form on a vast territory, which also contributes to an increase in the species diversity of the avifauna of the region. These two water objects served to research the fauna of water birds. We have researched the main species of avifauna, both nesting and found during migrations.

Extraction of connected river networks from multi-temporal remote sensing imagery using a path tracking technique

Precise delineation of river networks is important for accurate hydrological and flood modelling. Whilst remote sensing (RS) has showed great potential in monitoring hydrological changes over space and time, the existing RS-based methods extract river networks based on local morphologies and seldom take into account the overall hydrological connectivity of the rivers. The existing methods also commonly neglect the effect of seasonal variation of water surfaces and the existence of temporary water bodies, which deteriorate the precision of positioning river networks. To address these challenges, a new two-stage method is developed to Extract spatiotemporal variation of water surfaces based on Multi-temporal remote sensing Imagery and Delineate connected river networks with improved accuracy (EMID method for short) using a path tracking technique. The EMID method delineates connected river networks using (a) multi-temporal imagery and a Random Forest model to synoptically map the location and extent of water surfaces under different hydrological conditions, and (b) an optimization algorithm to find the best river paths based on water-occurrence frequency. Four drainage basins with various river morphologies are considered to validate EMID. Comparing with alternative methods, the EMID method consistently produces river network results with improved accuracy in terms of stream location, river coverage and network connectivity.

A comparison between active and passive communities of Ostracoda (Crustacea) in a tropical temporary lake

ABSTRACT Some microcrustaceans living in temporary waterbodies produce drought-resistant stages under adverse conditions. These structures accumulate in the sediment, forming an egg bank in which eggs can remain viable for many years. Here, we evaluate the contribution of ostracod resting eggs to the structure of the active ostracod community in a tropical temporary lake located in the Upper Paraná River floodplain, Brazil. The active ostracod communities were sampled by hand net, while sediment samples (egg banks) were collected using a core sampler. Sediments were oven-dried, then re-hydrated with filtered lake water and kept in hatching chambers. A total of 13 ostracod species were recorded, eight species in the passive community,and nine species in the active community, four species were recorded in both communities. The species composition between active and passive communities was significantly different. Five species of the active community could be of allochthonous origin and are most likely introduced by flooding or by other dispersal vectors. In conclusion, the egg bank adds species not necessarily found in the active community, thus acting in the maintenance and enrichment of the local and regional faunas.