Lake Habitats Research Articles

Keanekaragaman Jenis Burung pada Berbagai Tipe Habitat di Pulau Belitung

Belitung Island is a satellite island of the mainland of Sumatra Island. So far, bird research has been very rare and there have been almost no recent publications, so research on birds on Belitung Island is needed. The research was conducted during February-April 2020 in seven habitat types in 18 locations. Data were taken using the IPA (Index Point of Abundance) method with observation times between 05.30-09.00 am and 03.00-06.00 pm. Qualitative analysis was carried out on the bird status, while quantitative analysis was carried out using: 1) chi-square for bird species richness; 2) Shannon-Wiener diversity index (H'); 3) evenness index (E); and 4) bird community similarity index (IS). There were 111 bird species from 40 families and 13 orders. The birds found significantly different between habitat types for the number of species (χ²count = 23.73; df = 6; P < 0.05) and the number of individuals (χ²count = 361.65; df = 6; P < 0.05). The number of bird species found ranged from 14 species (lake habitat) to 50 bird species (coastal habitat). One bird species can be found in all habitat types, namely Cinnyris jugularis. Nine species of shorebirds were found. The bird diversity index (H') was obtained at 3.83 which is included in the high category and the bird evenness index (E) was obtained at 0.81 which is included in the high category and means the community is stable. The community similarity index (IS) values between habitat types ranged from 0.10-0.33.

Seasonal habitat use of yellow perch Perca flavescens in a north‐temperate lake

AbstractKnowledge of species‐specific fish biology, ecology, and habitat use is critical for informing science‐based management. Yellow perch Perca flavescens are an ecologically and recreationally important fish species. Yet, for many north‐temperate systems (e.g. inland lakes of Wisconsin), little is known about yellow perch seasonal habitat use and ecology. We characterised yellow perch seasonal spatial distribution, size–structure, and condition between littoral and pelagic habitats in Crystal Lake (Vilas Co., WI) during the open water period of 2021. Seasonal spatial distribution and population size–structure were characterised by contemporaneous sampling in littoral and pelagic habitats using mini‐fyke nets and vertical gill nets, respectively. Relative abundance estimates for yellow perch in the littoral zone were greatest during early spring and declined throughout the open water season. Yellow perch pelagic relative abundance estimates were lowest in spring, peaked at the onset of stratification, and then declined and remained relatively consistent throughout the open water season. In general, yellow perch population size–structure and condition were greatest in the pelagic zone. Our findings suggest that after spring spawning, larger yellow perch prefer/select pelagic habitats, while sub‐adults and juveniles prefer/select littoral habitats, potentially resulting from increased predator refugia and(or) resource availability. Our results emphasise the importance of evaluating gear and fishery assessment bias, particularly when the target species may use a range of habitat types within a system.

Impact of the Invasive Alien Macrophyte Ludwigia hexapetala on Freshwater Ecosystems: Evidence from Field Data.

Biological invasions are a serious threat to biodiversity conservation, especially in freshwater ecosystems. The American macrophyte Ludwigia hexapetala, which colonizes both the aquatic and bank habitats of lakes, rivers, and canals, is invading many waterbodies in Europe, becoming an increasingly worrisome threat in several European countries, including Italy. However, only fragmentary information is available on the actual impact of its invasion in these habitats. This study aims to collect field data from various freshwater habitats in central and northern Italy, to assess the possible impact of L. hexapetala on the environmental parameters and plant biodiversity of the invaded habitats. The results show that in aquatic habitats, dense floating L. hexapetala populations reduce the light levels and oxygen available in the water, consequently limiting the growth of other aquatic plants. Indeed, L. hexapetala populations negatively affect aquatic plant diversity, as an increase in L. hexapetala cover corresponded to a decrease in Simpson's diversity index. In contrast, in bank habitats, L. hexapetala has no significant impact on plant diversity. Evidence suggests that some native species, such as Phragmites australis, which generally form compact populations along the banks, effectively counteract the invasion of L. hexapetala. This information may prove valuable for the environmental managers of those freshwater habitats where L. hexapetala invasion needs to be addressed and controlled.

Ecological function zoning of Nansi Lake Basin in China based on ecosystem service bundles.

Ecological function zoning is an essential means of scientific management of ecosystems. According to the characteristics of ecological function zoning, implementing zoning control is conducive to the governance and protection of the ecological environment and the maintenance of ecological sustainability. This study was conducted with the Nansi Lake Basin as the cross-section for 2018. The Integrated Valuation of Ecosystem Services and Trade-offs model was adopted to assess and measure five ecosystem services, including water yield, crop production, soil conservation, carbon storage and carbon sequestration, and habitat quality. The Self-Organizing Feature Maps neural network was applied to obtain the ecosystem service bundles, and then, the ecological function zones were divided. The results indicated that the overall spatial pattern of ecosystem services in the study zone showed a decreasing schema from east to west; There was a trade-off between supply services and support services and a synergy between supply services and regulatory services; according to the bundling results, the Nansi Lake Basin was divided into four ecological functional zones: the eastern ecological surplus zone, the central crop supply zone, the western ecological balance zone, and the lake habitat protection zone. The results showed that (1) the spatial distribution of various ecosystem services in the Nansi Lake Basin showed spatial heterogeneity and specific regional laws, showing a decreasing pattern from the east to the west as a whole, especially in soil conservation, carbon sequestration, and habitat quality. (2) According to the supply and spatial distribution of each ecosystem service, the Nansi Lake Basin was divided into four ecological functional zones: the eastern ecological surplus zone, the central crop supply zone, the western ecological balance zone, and the lake habitat protection zone. (3) For zone I, provisioning services and regulation services were in synergy. For zone II and zone III, the provisioning service had a trade-off relationship with the regulation service and the supporting service. For zone IV, supporting services were trade-offs not only with provisioning services but also with regulating services. In general, the trade-offs between ecosystem service in the Nansi Lake Basin were stronger than the synergies, and the overall benefits of ecosystem services were smaller. Relying on the perspective of the ecosystem service bundles, at the county level, this study provided an analysis of the trade-offs and synergies among ecosystem services in the Nansi Lake Basin, which helped formulate the management plan for the corresponding region and provided the appropriate recommendations for regional habitat conservation and restoration.

Spatio-temporal variation in avian taxonomic, functional, and phylogenetic diversity and its relevance for conservation in a wetland ecosystem in Myanmar

Wetland ecosystems host an extensive number of avian species and play therefore a key role in biodiversity conservation. However, avifauna in wetlands is severely impacted by the anthropogenic transformation of natural habitats into other land uses. Understanding how habitat changes influence avian community dynamics is crucial for effective management and conservation of bird habitats. Here, we assessed spatio-temporal variation in taxonomic, functional, and phylogenetic diversity, and assembly structures of the bird community in the Indawgyi Wetland Ecosystem in Myanmar. Bird surveys were seasonally conducted at 120 sample plots, which were equally distributed among four habitat types subject to different level of human influences (natural lake habitat, seasonally flooded grasslands, riparian forest, and agricultural land). Across habitat types, functional and phylogenetic diversity were the highest in the lake habitat, especially during the migration season, and the lowest in the cultivated habitat. Our results indicated over-dispersed functional and phylogenetic structures in the lake habitat, with clustered structures in the remaining habitats. Diversity of species important for conservation was also higher in the lake habitat and in areas far away from human disturbances. Spatial variation of bird community diversity suggests that conservation efforts in this ecosystem should concentrate more on the lake habitat and associated grassland habitats. Moreover, our results suggest the need for habitat restoration in riparian forests and increased sustainable agricultural practices in order to improve the contribution of these habitats to the diversity in the avifauna community. Our study highlighted the importance of integrating functional and phylogenetic dimensions into biodiversity analyses providing broader ecological insights for conservation.

Short-term responses of macroinvertebrate assemblages to the “ten-year fishing ban” in the largest highland lake of the Yangtze basin

The rapid decline of freshwater biodiversity caused by overfishing has led to the implementation of a series of conservation measures, including fishing bans. However, existing studies have mostly focused on the effects of fishing bans on economically important species, while impacts on freshwater macroinvertebrates in lake ecosystems have been rarely studied. This study used a before-and-after methodology to determine the short-term effects of the “ten-year fishing ban” on the macroinvertebrates of the Dianchi Lake, the largest highland freshwater lake in the upper Yangtze basin, between 2015 and 2022. Following the fishing ban, the overall macroinvertebrate species richness (median [interquartile]) across sites increased from 4 [2–6] to 5 [4–7]. The total density increased from 128 [80–272] to 212 [140–325] n/m2. The median biomass increased from 0.18 [0.08–0.41] to 0.51 [0.26–2.36] g/m2. In particular, the Chironomidae density in the offshore sites increased from 16.00 [0.00–32.00] to 33.30 [16.00–48.00] n/m2, and the biomass increased from 0.03 [0.00–0.09] to 0.16 [0.07–0.22] g/m2. Within the inshore sites, the aquatic insect density increased from 4 [1.33–15.33] to 56 [22.00–86.67] n/m2. The Malacostraca density increased from 34.67 [11.67–95.33] to 110 [53.33–223.33] n/m2, and the biomass increased from 0.43 [0.11–1.00] to 1.48 [0.50–2.00] g/m2. Two endangered Margarya species were rediscovered at multiple sites compared to the pre-fishing ban period. A significant change in macroinvertebrate community structure across the lake was observed, which can be largely attributed to the fishing ban. The immediate increase in species richness, density, and biomass of most macroinvertebrate species suggests a combination of effects from both reduced exploitation pressure and lessened disturbances on lake habitats. The findings indicate that the fishing ban is beneficial for the recovery of most macroinvertebrate species in freshwater lakes.

Bibi by Jo Weaver (review)

Reviewed by: Bibi by Jo Weaver Kate Quealy-Gainer, Editor Weaver, Jo Bibi; written and illus. by Jo Weaver. Peachtree, 2023 [32p] Trade ed. ISBN 9781682635537 $18.99 Reviewed from digital galleys R 4-8 yrs Bibi the flamingo has been with the flock so long that most of the other birds have been under her care at some point, as she showed them how to preen their feathers, stand on one leg, and build nests for their babies. When the hot sun leaves what was their lake habitat parched and dry, the flock must travel to find water, but the little ones can't fly yet. No worries, Bibi will guide the young flamingos on foot while the others fly ahead, and just as always, Bibi keeps her charges safe, and the flock reunites to spend the summer in cool waters and shade. When the time comes to move on again, however, Bibi is feeling old and tired and worries she won't be able to make this flight. This earnest picture book is a lovely little ode to the valuable wisdom of elders and the reciprocity of love and care across generations, and young viewers will be relieved to see the other birds tend to Bibi until she gets her strength back. As the clear matriarch of the flock, Bibi is warm but firm, and Weaver manages the tricky feat of giving character and social dynamics to the birds without rendering them cutesy or overly precious. That balance comes through in the charcoal and digital illustrations with close-ups of individual interactions focusing on the birds' expressive faces while larger, full-bleed spreads emphasize [End Page 272] their wildness and odd beauty. Subtle hues of pink and salmon (no bubblegum pinks here) are shaded with darker colors to create movement and texture, and in a particularly striking scene, the birds are shown in silhouette as they cross the cracking, dry land. The avian subjects and thematic connection to the handing down of generational wisdom makes this UK import an excellent primer for Guojing's The Flamingo (BCCB 9/22). [End Page 273] Copyright © 2023 The Board of Trustees of the University of Illinois

Sunlight irradiation promotes both the chemodiversity of terrestrial DOM and the biodiversity of bacterial community in a subalpine lake

Alpine lake habitats are evolving into subalpine lakes under the scenario of climate change, where the vegetation are promoted due to increasing temperature and precipitation. The abundant terrestrial dissolved organic matter (TDOM) leached from watershed soil into subalpine lakes would undergo strong photochemical reaction due to the high altitude, with the potential to alter DOM composition and affect the bacterial communities. To reveal the transformation of TDOM by both photochemical and microbial processes in a typical subalpine lake, Lake Tiancai (located 200 m below the tree line) was chosen. TDOM was extracted from the surrounding soil of Lake Tiancai and then subjected to the photo/micro-processing for 107 days. The transformation of TDOM was analyzed by Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and fluorescence spectroscopy, and the shift of bacterial communities was analyzed using 16s rRNA gene sequencing technology. Dissolved organic carbon and light-absorbing components (a350) decay accounted for approximately 40% and 80% of the original, respectively, in the sunlight process, but both less than 20% in the microbial process for 107 days. The photochemical process promoted the chemodiversity as there were ∼7000 molecules after sunlight irradiation, compared to ∼3000 molecules in the original TDOM. Light promoted the production of highly unsaturated molecules and aliphatics, which were significantly associated with Bacteroidota, suggesting that light may influence bacterial communities by regulating the DOM molecules. Carboxylic-rich alicyclic molecules were generated in both photochemical and biological processes, suggesting TDOM was converted to a stable pool over time. Our finding on the transformation of terrestrial DOM and the alternation of bacterial community under the simultaneously photochemical and microbial processes will help to reveal the response of the carbon cycle and lake system structure to climate change for high-altitude lakes.

Negligible native and significant alien colonization of artificial shoreline by macroinvertebrates in a large shallow lake (Lake Balaton, Hungary)

The aim of our study was to compare the richness and composition of macroinvertebrate assemblages in natural reed and artificial rip-rap habitats in a shallow lake 50+ years after shoreline modifications. Lake Balaton (Hungary) provided a unique study system as approximately half of its shoreline (c.105 km) has been modified. Littoral macroinvertebrates were collected in two habitat types (artificial rip-rap and natural reed) around the shoreline over two seasons. We found that native taxon richness of rip-rap habitat was only one-twentieth of the natural reed habitat. Rip-rap habitat harboured significantly more alien species. We found that the proportion of alien taxa was higher in rip-rap habitat (89.2%) than in reed habitat (16.7%). The composition of macroinvertebrate assemblages in the two habitats was also significantly different with limited to moderate overlap. Furthermore, all 8 indicator taxa of rip-rap habitat were alien, whilst all 28 indicator taxa were native in reed habitat. These results suggest that artificial engineering structure creates a novel ecosystem dominated by alien species.

Seasonal and diurnal patterns of littoral microhabitat use by fish in gravel pit lakes, with special reference to supplemented deadwood brush piles

The habitat quality of the littoral zone is of key importance for almost all lentic fish species. In anthropogenically created gravel pit lakes, the littoral zone is often structurally homogenized with limited fish habitats. We supplemented deadwood brush piles in the littoral zone of eight gravel pit lakes and investigated the diurnal and seasonal use of this and other typical microhabitats by six dominant fish species. Shoreline habitats were sampled using point abundance electrofishing during day and night in all four seasons, and patterns of fish abundance were compared amongst unstructured littoral habitats, emerged macrophytes and brush piles. We caught a total of 14,458 specimens from 15 species in the gravel pit lakes. Complex shoreline structures were used by all fish species that we examined, especially during daytime, whilst the use of unstructured habitats was highest during night. The newly added brush piles constituted suitable microhabitats for selected fish species, perch (Perca fluviatilis), roach (Rutilus rutilus) and pike (Esox lucius), particularly during winter. Supplemented deadwood provides suitable fish habitat in gravel pit lakes and may to some degree compensate for the loss of submerged macrophytes in winter by offering refuge and foraging habitat for selected fish species.

A meta-analysis reveals that geographical factors drive the bacterial community variation in Chinese lakes

The biogeographical distribution of plants and animals has been extensively studied, however, the biogeographical patterns and the factors that influence bacterial communities in lakes over large scales are yet to be fully understood, even though they play critical roles in biogeochemical cycles. Here, bacterial community compositional data, geographic information, and environmental factors were integrated for 326 Chinese lakes based on previously published studies to determine the underlying factors that shape bacterial diversity among Chinese lakes. The composition of bacterial communities significantly varied among the three primary climatic regions of China (Northern China, NC; Southern China, SC; and the Tibetan Plateau, TIP), and across two different lake habitats (waters and sediments). Sediment bacterial communities exhibited significantly higher alpha-diversity and distance-decay relationships compared to water communities. The results indicate that the “scale-dependent patterns” of controlling factors, primarily influenced by geographical factors, become increasingly pronounced as the spatial scale increases. At a national scale, geographical factors exerted a dominant influence on both the water and sediment communities across all lakes, as geographical barriers restrict the dispersal of individuals. At smaller spatial scales, temperature-driven selection effects played a greater role in shaping water bacterial community variation in the NC, SC, and TIP, while geographical factors had a stronger association with sediment bacterial community variation in the lakes of the three regions. This synthesis offers novel insights into the ecological factors that determine the distribution of bacteria in Chinese lakes.

Sediment prokaryotic microbial community and potential biogeochemical cycle from saline lakes shaped by habitat

The microbial diversity and ecological function in different saline lakes was reduced or disappeared as the influence of climate change and human activities even before they were known. However, reports about prokaryotic microbial of saline lakes from Xinjiang are very limited especially in large-scale investigations. In this study, a total of 6 saline lakes represented three different habitats, including hypersaline lake (HSL), arid saline lake (ASL), and light saltwater lake (LSL) were involved. The distribution pattern and potential functions of prokaryotes were investigated by using the cultivation-independent method of amplicon sequencing. The results showed that Proteobacteria was the predominant community and was widely distributed in all kinds of saline lakes, Desulfobacterota was the representative community in hypersaline lakes, Firmicutes and Acidobacteriota were mainly distributed in arid saline lake samples, and Chloroflexi was more abundant in light saltwater lakes. Specifically, the archaeal community was mainly distributed in the HSL and ASL samples, whereas it was very rare in the LSL lakes. The functional group showed that fermentation was the main metabolic process of microbes in all saline lakes and covered 8 phyla, including Actinobacteriota, Bacteroidota, Desulfobacterota, Firmicutes, Halanaerobiaeota, Proteobacteria, Spirochaetota, and Verrucomicrobiota. Among the 15 functional phyla, Proteobacteria was a distinctly important community in saline lakes, as it exhibited wide functions in the biogeochemical cycle. According to the correlation of environmental factors, SO42-, Na+, CO32-, and TN were significantly affected in the microbial community from saline lakes in this study. Overall, our study provided more detailed information about microbial community composition and distribution from three different habitats of saline lakes, especially the potential functions of carbon, nitrogen, and sulfur cycles, which provided new insight for understanding the complex microbiota adapt to the extreme environment and new perspectives on evaluating microbial contributions to degraded saline lakes under environmental change.

Past and future climate change effects on the thermal regime and oxygen solubility of four peri-alpine lakes

Abstract. Long-term effects of climate change on lakes globally will include a substantial modification in the thermal regime and the oxygen solubility of lakes, resulting in the alteration of ecosystem processes, habitats, and concentrations of critical substances. Recent efforts have led to the development of long-term model projections of climate change effects on lake thermal regimes and oxygen solubility. However, such projections are hardly ever confronted with observations extending over multiple decades. Furthermore, global-scale forcing parameters in lake models present several limitations, such as the need of significant downscaling. In this study, the effects of climate change on thermal regime and oxygen solubility were analyzed in the four largest French peri-alpine lakes over 1850–2100. We tested several one-dimensional (1D) lake models' robustness for long-term variations based on up to 63 years of limnological data collected by the French Observatory of LAkes (OLA). Here, we evaluate the possibility of forcing mechanistic models by following the long-term evolution of shortwave radiation and air temperature while providing realistic seasonal trends for the other variables for which local-scale downscaling often lacks accuracy. Based on this approach, MyLake, forced by air temperatures and shortwave radiations, predicted accurately the variations in the lake thermal regime over the last 4 to 6 decades, with RMSE < 1.95 ∘C. Over the previous 3 decades, water temperatures have increased by 0.46 ∘C per decade (±0.02 ∘C) in the epilimnion and 0.33 ∘C per decade (±0.06 ∘C) in the hypolimnion. Concomitantly and due to thermal change, O2 solubility has decreased by −0.104 mg L−1 per decade (±0.005 mg L−1) and −0.096 mg L−1 per decade (±0.011 mg L−1) in the epilimnion and hypolimnion, respectively. Based on the shared socio-economic pathway SSP370 of the Intergovernmental Panel on Climate Change (IPCC), peri-alpine lakes could face an increase of 3.80 ∘C (±0.20 ∘C) in the next 70 years, accompanied by a decline of 1.0 mg L−1 (±0.1 mg L−1) of O2 solubility. Together, these results highlight a critical alteration in lake thermal and oxygen conditions in the coming decades, and a need for a better integration of long-term lake observatories data and lake models to anticipate climate effects on lake thermal regimes and habitats.

Environmental extremes affect productivity and habitus of common reed in intermittent wetland

This article describes the effect of extreme water level events and extreme temperatures on the primary productivity and habitus of the common reed (Phragmites australis) growing in lake and riparian habitats at intermittent Lake Cerknica between 2007 and 2021. At each sampling site, the above-ground biomass, leaf biomass and shoot density per m2, the number of internodes and leaves per plant, average shoot height, shoot basal diameter and the ratio of flowering plants per total plant number were determined. Stand and plant properties varied significantly between the locations, with exception of the basal diameter, that varied less. Biomass per area and per plant showed the trend of decrease across years, but the reed density remained at the same level. Redundancy analysis of the relationships between environmental parameters and productivity and habitus parameters revealed the importance for the lake stand of high-water level parameters in the 4th quarter of the previous year, while the 1st quarter of the current year was important for the riparian stand. High water level variables explained 60% of variance of productivity parameters of the lake stand and 21% of those of the riparian stand. For low water level parameters, the explained variance was 51 and 24%, respectively. In the case of habitus parameters, variances explained by high water level parameters were 66% for lake stand and 34% for riparian stand and of low water level parameters, the corresponding variances were 45% for lake stand and 59% for riparian stand. Temperature extremes can explain the lower variance. The interrelation between wetland hydrological extremes and reed stand/plant properties that was obtained suggests that an ecohydrological approach may provide a basis for successful management of reed-colonised wetlands.

Habitat quality–physicochemical water quality–littoral macroinvertebrate community nexus in Lugo Lake (Ethiopia): Priorities for sustainable water resources management

AbstractThe integration of water quality characteristics with habplot‐based habitat quality assessment score (HabQA) has received little attention in ecological quality assessment studies. This study investigated the macroinvertebrate community structure in relation with lake habitat quality and physicochemical water quality variables in Lugo Lake (Ethiopia). Twelve sampling sites (eight agricultural and four recreational) were included. The variation among macroinvertebrates data was significantly explained by HabQA score and soluble reactive phosphorus. The study revealed the greater importance of habitat quality characteristics in comparison with the other conventional physicochemical characteristics on macroinvertebrate community structure. We strongly recommend the use of HabQA system while studying macroinvertebrate community structure for a deeper understanding of the environmental functioning of tropical lakes. The results suggested the need to apply integrated and sustainable protection and management of the lake catchment (including wetlands) to enhance the ecological integrity and hence biodiversity of lakes.

Effects of nutrient reduction and habitat heterogeneity on benthic macroinvertebrate assemblages in a large shallow eutrophic lake

The Taihu Lake ecosystem has been subjected to numerous anthropogenic stressors during the past decades, leading to substantial changes in nutrient dynamics and habitat quality. For instance, the northwestern lake bays receive large amounts of nutrient-rich wastewater and have frequently experienced algal blooms, while the eastern lake region is still dominated by submersed macrophytes. Such changes in environmental characteristics can greatly impact benthic macroinvertebrate communities. We used a 15-year monitoring data series collected by the Taihu Laboratory for Lake Ecosystem Research to examine the spatial and temporal variations of the benthic invertebrate fauna and evaluate its status and trends. We found that three major communities could be distinguished based on taxonomic group composition and abundance, and these corresponded well with three lake habitat types: algal-dominated, macrophyte-dominated, and open-lake zone. An analysis of temporal trends showed major changes in the macroinvertebrates during the study period, largely driven by a lake-wide and significant decline in the abundance of pollution-tolerant taxa. The spatial and temporal variations of macroinvertebrate communities were mainly explained by nutrients (e.g., total nitrogen and ammonium concentrations) and habitat factors (e.g., sediment substrates and macrophyte biomass) as indicated by Random Forests regression, but the major drivers of macroinvertebrate density differed among the three lake zones at the temporal scale. Moreover, our findings suggest that benthic invertebrates were more sensitive to the improvement of the lake's environmental conditions than the pelagic community was. This study provides insights into the responses of macroinvertebrates to ecological dynamics in lakes and highlights the importance of continued monitoring for tracking long-term changes.

Identification and environmental background of Chara remains in the Holocene sequence of Lake Peţea (NW Romania) and the possibilities of using the results in archaeobotany

The charophyte remains play an important role in the reconstruction of the hydrological characteristics (pH, water depth, stream flow, carbonate content, isotope geochemistry-water chemistry and temperature) of the former lake habitats. This is of particular importance in environmental historical studies, since the possibilities for obtaining aquatic food resources and the techniques and tools used are fundamentally influenced by these hydrological conditions. Our gyrogonite samples were recovered from the Holocene sequence of the thermalspring fed Lake Peţea NW Romania. The presence of the recovered Chara cf. hispida Linnaeus, 1753 gyrogonites marks the emergence of an oligotrophic shallow water lake system characterized by high dissolved Ca and Mg content and relatively poor plant cover in the Early Holocene. The results of previous malacological and ostracod studies also indicate the development of a shallow water lake with a muddy substrate and water temperatures above 18°C. As a warm-water lake, the local micro-environment was also home to many exploitable tree species. The charophyte remains that we recovered were from the Mesolithic level of the lake, so we were able to provide information on the hydrology of the lake for this period. Unfortunately, there have been no detailed archaeological investigations in the area to date revealing any potentially Mesolithic remains. Thus, no information is currently available on actual human occupation from the period in question.

Ornithological Survey and Habitat Quality Study in Rara Lake, Nepal

Rara Lake is situated in mountain ecoregion serves as staging post for the long range migratory wetland birds. The lake ambient forest bears the restricted range and globally threatened species. Bird species in the park is reported as unrecorded while habitat quality of the Rara lake providing the refuge to migratory and native bird species is degrading. Adherence to the statement, study was carried to gather the descriptive and evidence- based information on bird species and habitat quality was carried to understand bird status, its activities and habitat quality. Bird count was carried through line transect. Bird behavior, activities, stay-length and lake riparian habitat was noted through direct sighting. Water quality was assessed following American Public Health Association water quality test guideline. The study counted a total of 2415 bird individuals from listed 104 species including 16 migratory Waterfowls, 13 wetland dependent birds and 75 forest birds. The observed bird species ranged from frequent to very uncommon winter visitor stop in Rara lake primarily for fueling during migration. Observed that most of time birds were foraging at shallow water but merely outside lakes. Discarded trashes in the roosting and foraging site and around the lake circuit trail triggering threats to waterfowls and aquatic biodiversity while higher human movement through the trail causing disturbance to waterfowl. Water quality assessment revealed that Phosphorous and ammonia concentration in Rara lake were higher than the recommended level for freshwater/aquatic ecosystem connoting lake in the process of eutrophication and acute ammonia toxicity affecting aquatic life. Regular assessment of water quality is required preventing aquatic life from detrimental effects. Continuous monitoring to study their migratory behavior and habitat qualities would be essential to inform conservation policies also linking with eco-tourism activities.

DIVERSITY, ABUNDANCE, AND SPECIES RICHNESS OF AERIAL INSECTS IN DRY LAND OF KEFAMENANU, NORTH CENTRAL TIMOR, EAST NUSA TENGGARA

Abstract: It is important to conduct this research to determine the diversity, species richness, and even distribution of aerial insects based on habitat characteristics in the dry land of Kefamenanu city, North Central Timor, East Nusa Tenggara. The research was conducted on three types of habitats, namely dry land, rivers, and lakes by purposive sampling method. Sampling was done by documenting specimens in each habitat, identified, inventoried, and analyzed quantitatively to obtain data on species diversity, species richness, and evenness of insect species. Results revealed that aerial insects in Kefamenanu City contained 9 orders, 25 families, 44 genera, 54 species, 1998 individuals in three habitat types with diversity index (H'=3,068), evenness index (E=0.774), richness index (R). = 6.974), and dominance index (0.074). Aerial insects in dry land habitat found in 8 orders, 18 families, 32 genera, 32 species, 514 individuals with diversity index (H'=2.735), evenness index (E=0.789), richness index (R=4.966), and dominance index. (0.092). Aerial insects in river habitat found 7 orders, 20 families, 40 genera, 47 species, 792 individuals with diversity index (H'=3.205), evenness index (E=0.833), richness index (R=6.892), and dominance index (0.075). Aerial insects in lake habitat found 8 orders, 18 families, 35 genera, 39 species, 692 individuals with diversity index (H'=2,906), evenness index (E=0.793), richness index (R=5.811), and dominance index (0.083).
 Keywords: dry land, aerial insect, species diversity, species richness, species evenness

Drivers of contemporary lacustrine fish species richness in the glacial Lake Agassiz basin

AbstractAimBiological communities are the result of a stepwise spatiotemporal filtering process, driven by large‐scale historical and local contemporary determinants. The biogeographical pattern and species richness of North American fishes are predominantly determined by historical processes of past glaciations and postglacial dispersal and by contemporary environmental and ecological processes. We evaluated the effects of postglacial dispersal through glacial Lake Agassiz and habitat heterogeneity, represented by lake surface area, on contemporary freshwater fish species richness patterns of northwestern Ontario lakes.LocationNorthwestern Ontario, Canada.TaxonFreshwater fishes.MethodsApplying the theory of island biogeography and species–area curves, we examined the effects of isolation from the past dispersal corridor of glacial Lake Agassiz and habitat heterogeneity on species richness across 264 contemporary lakes. While controlling for correlations among the predictor variables, generalized linear models were constructed between species richness, as the response variable and the explanatory variables of lake elevation and surface area, and connection to the dispersal corridor.ResultsDifferential cover by glacial Lake Agassiz led to variation in fish species richness across contemporary lakes and it is higher in lakes that were covered by Lake Agassiz relative to basins remaining outside of the boundaries of the glacial lake. Lake surface area is the strongest predictor of species richness, while lake elevation is the strongest factor predicting isolation.Main ConclusionsHabitat heterogeneity and postglacial colonization have led to differences in fish richness within the same geographical region, which increases with lake surface area and decreases with elevation. These are likely driven by greater niche diversity facilitating the assembly of more diverse communities and isostatic rebound and fluctuating levels of Lake Agassiz isolating lakes at high elevations from the dispersal route earlier during the colonization process, respectively. These patterns underscore the importance of incorporating historical and environmental community determinants in biodiversity studies.