Lake Assemblages Research Articles

Eutrophication is better indicated by functional traits than taxonomic composition of macroinvertebrate assemblages in floodplain lakes

Eutrophication is better indicated by functional traits than taxonomic composition of macroinvertebrate assemblages in floodplain lakes

Correction: Comparative effects of river–lake disconnection on taxonomic and functional composition of molluscan assemblages in floodplain lakes

Correction: Comparative effects of river–lake disconnection on taxonomic and functional composition of molluscan assemblages in floodplain lakes

Comparative effects of river–lake disconnection on taxonomic and functional composition of molluscan assemblages in floodplain lakes

Comparative effects of river–lake disconnection on taxonomic and functional composition of molluscan assemblages in floodplain lakes

Native fish assemblages in natural lakes across Japan: Endemism deterioration lasting centuries

AbstractAimThis study aimed to illustrate the changing diversity patterns of native freshwater fish in the past two centuries and to identify priority locations for native fish conservation to counter future degradation.LocationJapanese archipelago.MethodsWe used the published native fish fauna data in 39 lakes across Japan, analysing historical and current diversity and projecting future distribution patterns based on the Japanese Red List. We assessed fish assemblages' taxonomic, phylogenetic, and functional alpha and beta diversity across different periods. Additionally, we proposed a cumulative diversity index that incorporated taxonomic, phylogenetic and functional facets, and then examined its relationship with the latitudinal positioning of the lakes across periods.ResultsWe observed a significant decrease in the richness of native freshwater fish since historical periods. Accompanying this decline were significant reductions in both phylogenetic relatedness and functional redundancy. Fish beta diversity increased from the past to the present and is predicted to decline drastically, indicating an ongoing homogenization process. Using the cumulative diversity index, we identified Hokkaido and Kyushu as crucial habitats for endemic fishes. These islands, with unique biogeographical backgrounds, contributed substantially to the national dissimilarity patterns of native fish assemblages in the historical period. However, the contribution is diminishing due to the ongoing decline in fish endemism.Main ConclusionsThe conservation priority of native freshwater fish in Japan should be assigned to Hokkaido and Kyushu due to the inhabited endemic species. The proposed framework for assessing the cumulative diversity of biotic communities presented the potential to aid macroecological explorations that underpin biodiversity conservation.

Integrated evaluation of the impact of water diversion on water quality index and phytoplankton assemblages of eutrophic lake: A case study of Yilong Lake

Water diversion has been widely utilized to enhance lake water quality and mitigate cyanobacterial blooms. However, previous studies have mainly focused on investigating the effects of water diversion on water quality or aquatic ecological health. Consequently, there is limited research investigating the combined impact of water diversion on the water quality and the ecological health of eutrophic lakes, and whether the WQI and phytoplankton assemblages demonstrate similar patterns following water diversion. In this study, the effects of water diversion on the ecosystem health of eutrophic lakes were comprehensively evaluated based on the WQI indices and phytoplankton assemblages during the NWDP-21 and WDP-22. The results showed that the annual mean of WQI increased from 52.02 to 54.36 after water diversion, which improved the water quality of the lake, especially NH3–N and TN decreased by 58.6% and 15.2%, respectively. The phytoplankton assemblages changed significantly before and after water diversion, and we observed that the total biomass of phytoplankton decreased by 12.3% and phytoplankton diversity indices (Shannon-Wiener diversity, Pielou evenness, and Simpson index) increased by 8.6%–8.9% after water diversion, with an improvement in the connectivity and stability of the phytoplankton. Notably, enhanced adaptations of rare sub-communities for resource use in water diversion environments, and water diversion inhibited the dispersal ability of dominant functional groups, and the effects of hydrological disturbances on the structure of phytoplankton assemblage favored the ecological health of eutrophic lakes. VPA analysis further reveals that water diversion alters the drivers of phytoplankton functional group biomass and phytoplankton diversity. The results of the PLS-PM analysis clarify that water diversion indirectly impacts the total phytoplankton biomass and phytoplankton diversity primarily by modifying light availability. Significant correlations are observed between the dominant functional groups biomass and diversity indices of WQI. The trends in changes observed in water quality indices and phytoplankton following water diversion align with the evaluation of water ecological health. This study provides valuable guidance for the ecological management of the diversion project in Yilong Lake and serves as a reference for similar projects in other lakes.

Autecology of the extant ostracod fauna of Lake Ohrid and adjacent waters - a key to paleoenvironmental reconstruction

Understanding the ecology of bioindicators such as ostracods is essential in order to reconstruct past environmental and climate change from analysis of fossil assemblages preserved in lake sediment cores. Knowledge of the ecology of ancient Lake Ohrid’s ostracod fauna is very limited and open to debate. In advance of the Ohrid ICDP-Drilling project, which has potential to generate high-resolution long-term paleoenvironmental data of global importance in paleoclimate research, we sampled Lake Ohrid and a wide range of habitat types in its surroundings to assess 1) the composition of ostracod assemblages in lakes, springs, streams, and short-lived seasonal water bodies, 2) the geographical distribution of ostracods, and 3) the ecological characteristics of individual ostracod species. In total, 40 species were collected alive, and seven species were preserved as valves and empty carapaces. Of the 40 ostracod species, twelve were endemic to Lake Ohrid. The most common genus in the lake was Candona, represented by 13 living species, followed by Paralimnocythere, represented by five living species. The most frequent species was Cypria obliqua. Species with distinct distributions included Heterocypris incongruens, Candonopsis kingsleii, and Cypria lacustris. The most common species in shallow, flooded areas was H. incongruens, and the most prominent species in ditches was C. kingsleii. C. lacustris was widely distributed in channels, springs, lakes, and rivers. Statistical analyses were performed on a “Lake Ohrid” dataset, comprising the subset of samples from Lake Ohrid alone, and an “entire” dataset comprising all samples collected. The unweighted pair group mean average (UPGMA) clustering was mainly controlled by species-specific depth preferences. Canonical Correspondence Analysis (CCA) with forward selection identified water depth, water temperature, and pH as variables that best explained the ostracod distribution in Lake Ohrid. The lack of significance of conductivity and dissolved oxygen in CCA of Ohrid data highlight the uniformity across the lake of the well-mixed waters. In the entire area, CCA revealed that ostracod distribution was best explained by water depth, salinity, conductivity, pH, and dissolved oxygen. Salinity was probably selected by CCA due to the presence of Eucypris virens and Bradleystrandesia reticulata in short-lived seasonal water bodies. Water depth is an important, although indirect, influence on ostracod species distribution, which is probably associated with other factors such as sediment texture and food supply. Some species appeared to be indicators for multiple environmental variables, such as lake level and water temperature.

Microbial assemblages in Arctic coastal thermokarst lakes and lagoons.

Several studies have investigated changes in microbial community composition in thawing permafrost landscapes, but microbial assemblages in the transient ecosystems of the Arctic coastline remain poorly understood. Thermokarst lakes, abrupt permafrost thaw features, are widespread along the pan-Arctic coast and transform into thermokarst lagoons upon coastal erosion and sea-level rise. This study looks at the effect of marine water inundation (imposing a sulfate-rich, saline environment on top of former thermokarst lake sediments) on microbial community composition and the processes potentially driving microbial community assembly. In the uppermost lagoon sediment influenced from marine water inflow, the microbial structures were significantly different from those deeper in the lagoon sediment and from those of the lakes. In addition, they became more similar along depth compared with lake communities. At the same time, the diversity of core microbial consortia community decreased compared with the lake sediments. This work provides initial observational evidence that Arctic thermokarst lake to lagoon transitions do not only substantially alter microbial communities but also that this transition has a larger effect than permafrost thaw and lake formation history.

Before and after mink fur farming: water chemistry and sedimentary diatom assemblages in lakes from southwestern Nova Scotia, Canada

Libera N, Rühland KM, Kurek J, Smol JP. 2024. Before and after mink fur farming: water chemistry and sedimentary diatom assemblages in lakes from southwestern Nova Scotia, Canada. Lake Reserv Manage. 40:18–35. Since the 1930s, farmed mink pelts have been an important contributor to the economy of rural Nova Scotia (NS, Canada). However, these farms are a potential source of pollutants to nearby ecosystems. To determine how regional lakes have been affected by fur farms, we compared modern water chemistry and sedimentary diatom assemblages in 14 lakes in southwestern Nova Scotia. We categorized lakes into 3 groups: (a) 5 lakes with fur farms in the catchment or near inlets; (b) 4 lakes downstream from or near fur farms; and (c) 5 reference lakes without hydrological connection to fur farms. To assess whether lake conditions have changed since the establishment of fur farms, we conducted a “before-and-after” paleolimnological analysis comparing surface sediments (representing modern environments) to dated sediments deposited prior to fur farm operations. Diatom assemblages registered distinct responses to eutrophication in several hypereutrophic lakes with farms within their catchment boundaries. In lakes ∼25 km downstream from fur farms, diatom assemblage changes were more characteristic of climate warming and acidification than of eutrophication, despite surface water nutrient concentrations well above levels in reference lakes. We found no association between the presence of fur farms and surface water trace metals that could potentially bioaccumulate and/or biomagnify. Our data indicate that decades of nutrient inputs from fur farms have caused eutrophication at several lakes where fur farms are close to the shoreline or to inlet streams.

Insight into diversity change, variability and co-occurrence patterns of phytoplankton assemblage in headwater streams: a study of the Xijiang River basin, South China.

Phytoplankton has been used as a paradigm for studies of coexistence of species since the publication of the "paradox of the plankton." Although there are a wealth of studies about phytoplankton assemblages of lakes, reservoirs and rivers, our knowledge about phytoplankton biodiversity and its underlying mechanisms in mountain headwater stream ecosystems is limited, especially across regional scales with broad environmental gradients. In this study, we collected 144 phytoplankton samples from the Xijiang headwater streams of the Pearl River across low altitude (< 1,000 m) located in Guangxi province, intermediate altitude (1,000 m < altitude <2,000 m) in Guizhou province and high altitude (> 2,000 m) in Yunnan province of China. Our study revealed high phytoplankton diversity in these streams. Freshwater phytoplankton, including cyanobacteria, Bacillariophyta, Chlorophyta, Rhodophyta, Chrysophyta, Euglenophyta, Glaucophyta, Phaeophyta and Cryptophyta, were all detected. However, phytoplankton alpha diversity exhibited a monotonic decreasing relationship with increasing altitude. High altitudes amplified the "isolated island" effect of headwater streams on phytoplankton assemblages, which were characterized by lower homogeneous selection and higher dispersal limitation. Variability and network vulnerability of phytoplankton assemblages increased with increasing altitudes. Our findings demonstrated diversity, variability and co-occurrence patterns of phytoplankton assemblages linked to environmental factors co-varying with altitude across regional scales.

Effects of nitrogen on benthic diatom assemblages in high-elevation central and eastern alpine lakes

ABSTRACT We explored patterns of benthic diatom composition across sixty-two high-elevation alpine lakes spanning a wide range of nitrogen (N) concentrations due to atmospheric deposition and background variation in lake and watershed characteristics. Our goals were to (1) assess the effect of lake water N concentration on benthic diatom composition during late summer or fall conditions and (2) identify policy-relevant response thresholds. The analyses were carried out on a large set of diatom and water chemistry data, integrated with new data. Multivariate and correlation analyses revealed associations between pH, N concentration, and benthic diatom composition, but the effects of pH and N were confounded. However, partial correlation analysis allowed us to identify “N-responsive diatoms”; that is, diatom taxa with nonspurious associations with N. Focusing on these taxa, we detected a decline in the abundance of taxa preferring low N concentrations and an increase in the abundance of taxa preferring high N concentrations starting at NO3 concentrations of approximately 5 µmol L−1. We interpreted this shift as an effect of watershed N saturation due to atmospheric deposition. Based on the results, we suggest a late-summer or fall concentration threshold of 5 µmol NO3 L−1 to prevent change in benthic diatoms in high-elevation alpine lakes.

Fish life-history traits predict abundance-occupancy patterns in artificial lakes

Life-history traits of a species have been postulated as a factor in abundance and occupancy patterns. Understanding how traits contribute to the ubiquity and rarity of taxa can facilitate the development of effective conservation policy by establishing a connection between species requirements and resource. The goal was to evaluate fish assemblages in artificial lakes for evidence of the abundance-occupancy patterns reported in natural environments and, if evident, to explore if observed patterns of abundance and occupancy could be attributed to species traits. Fish abundance and occupancy were estimated over 1990–2018 in 22 artificial lakes impounded within the Tennessee River basin, USA. Consistent with reports for many other taxonomic groups in natural environments, there was a positive association amidst 114 fish species between abundance and occupancy in artificial lakes (R2 = 0.78). This result indicates that the fish assemblages that develop in these anthropized environments follow the fundamental abundance-occupancy patterns uncovered in natural environments, despite assemblages having been disfigured by the dramatic rearrangement of habitats brought by impoundment. Moreover, a redundancy analysis focusing mostly on reproductive and habitat traits adequately predicted abundance-occupancy patterns of fish assemblages in artificial lakes (R2 = 0.69). Species abundance-occupancy is influenced by the interplay between life-history traits and habitat availability, even in artificial lakes, and by extension, possibly other artificial ecosystems.

Trace fossil zonation in interdune Lakes: example from the neogene of Eastern Patagonia, Argentina

The Upper Miocene-Lower Pliocene Río Negro Formation (Río Negro Province, Argentina) contains diverse and abundant continental trace fossils. The purpose of this contribution is to recognize distinctive trace fossil assemblages in interdune lakes as response to lake expansion and contraction. The interdune deposits host 23 invertebrate, vertebrate, and plant ichnotaxa that are linked to the hydrological dynamics of the lake. During lake expansion a highly diverse subaqueous trace fossil assemblage reflects an infaunal bivalve population living in a littoral zone with swampy vegetation and semiaquatic mammals. The trace fossil assemblage recorded during Lake Highstand is less diverse and mostly linked to bivalve-generated trace fossils reflecting resting, locomotion, and escape/equilibrium behaviour (comparable to the Mermia ichnofacies). The assemblage during lake contraction exhibits high ichnodiversity and is dominated by vertebrate trace fossils reflecting foraging activities of shorebirds, cursorial birds, and herding semiaquatic mammals and ground sloths frequenting water holes. Flat sandy areas with moist substrates marginal to the interdune lake displayed a moderate ichnodiversity and its distinctive components were armadillo meniscate burrows and footprints in cross-section, as well as subvertical calcareous root casts. Neogene interdune lacustrine deposits reflect a particular zonation of trace fossils in response to changing physical conditions.

The Caddisflies (Trichoptera) of Drummond Island, Michigan, With an Assessment of Lake Assemblage Biomass

The Caddisflies (Trichoptera) of Drummond Island, Michigan, With an Assessment of Lake Assemblage Biomass

Does littoral substrate affect macroinvertebrate assemblages in Mediterranean lakes?

The objective of this study was to investigate the effects of substrate type in macroinvertebrate assemblages in Mediterranean lakes. Samplings have taken place in the littoral zone of 21 lakes in Greece, between 2015 and 2018. We compared benthic macroinvertebrate assemblages among three substrate types of their littoral zones; sandy, covered with macrophytes and stony substrate. Benthic macroinvertebrate assemblages at sites with extended macrophyte cover differed only slightly in composition and abundance from the ones found in stony and sandy substrates. Coenagrionidae were indicative of sites covered with macrophytes and Oligochaeta and Erpobdellidae were representative of stony substrates. The type of substrate proved to be a statistically significant factor influencing the number of benthic macroinvertebrate taxa, the relative abundance of Oligochaeta and the relative abundance of Odonata. In the context of designing site-adapted management measures, priority could be given to the conservation and restoration of aquatic vegetation in lake littoral zones, which host rich macroinvertebrate assemblages with abundant taxa of Odonata.

Fish assemblages in lakes along environmental gradients at the eastern edge of Europe

Fish assemblages in lakes along environmental gradients at the eastern edge of Europe

Legacy effects of acidification and climate warming affect recent recovery of diatom assemblages in Sudbury-region lakes (Ontario, Canada)

Legacy effects of acidification and climate warming affect recent recovery of diatom assemblages in Sudbury-region lakes (Ontario, Canada)

Compositional and phylogenetic beta diversity reveal different patterns of aquatic plant assemblages in lakes along the Changjiang River

Many articles have examined the aquatic flora in lakes along the Changjiang River over the past four decades. However, studies on taxonomic and phylogenetic alpha and beta diversity of aquatic plants along the Changjiang River are lacking. In order to clarify the distribution pattern of aquatic plants in lakes of the Changjiang River, we comprehensively analyzed the phylogenetic structure, compositional beta diversity (CBD), and phylogenetic beta diversity (PBD) of their aquatic plant assemblages. We found strong regional differences in phylogenetic community structures with significant differences in the net relatedness index and nearest taxon index values at subregional scales. Interestingly, similarity clustering based on compositional beta similarity showed that the lakes in the upper Changjiang River and upper Pearl River were clustered into a branch, and then connected with the lakes in the lower Changjiang River. However, similarity clustering based on phylogenetic beta similarity clustered the lakes in the upper and lower Changjiang River together into a branch, before connecting them with the lakes in the upper Pearl River. Additionally, we found significantly higher taxonomic dissimilarity than phylogenetic dissimilarity overall, as well as in individual subregions of the Changjiang River. These results suggested that the uplift of the Qinghai-Tibet Plateau and river capture played important roles in the aquatic plant assemblages of lakes resulting in patterns of geographic endemism at regional scales.

Environmental factors are the major drivers of macroinvertebrate assemblage structure in southern Brazilian coastal lakes

AbstractCoastal freshwater lakes are distinctive landscape features in South America, and benthic macroinvertebrates are key to their ecological functioning. Identifying the main factors driving the assemblage structure of benthic macroinvertebrate is thus important for the development of management strategies in these ecosystems. However, studies on the drivers of macroinvertebrate assemblages are scarce in subtropical coastal lakes of the Neotropical region. Here, we evaluated the role of environmental (morphometric and water chemistry variables) and spatial factors in the assemblage structure of benthic macroinvertebrates in 36 coastal freshwater lakes in Brazil from 2008 to 2015. Macroinvertebrate family richness increased with ammonium, pH and water transparency, and decreased with nitrate content (slope ≈1 for all significant variables). Environmental factors explained most of the variation in macroinvertebrate composition (16%) compared to spatial ones (3.4%). In specific, Dugesiidae, Hydrobiidae, Corbiculidae, Sphaeromatidae, Noteridae, Hydropsychidae, Culicidae and Ceratopogonidae predominated in lakes with lower conductivity (&lt;100 μS/cm) and higher water transparency (&gt;1 m). Spatial factors summarized differences in macroinvertebrate assemblages between isolated and connected lakes. Although none of the lakes studied are directly impacted by organic pollution, our results suggest that benthic macroinvertebrate assemblages in subtropical coastal lakes are mostly structured by water chemistry, likely reflecting the major trends in land use along the study region (transition from agriculture to urban areas). We recommend that the conservation of macroinvertebrate biodiversity in southern Brazilian coastal lakes focus on the monitoring of water chemistry factors associated with human‐based land use.

Climate features or the composition of submerged vegetation? Which factor has a greater impact on the phytoplankton structure in temperate lakes?

This study compares the composition and biomass of phytoplankton assemblages of lakes with abundant vegetation dominated by (1) charophytes (Chara-lakes) and (2) angiosperms (Potamogeton-lakes). These two groups of submerged macrophytes effectively control the phytoplankton development in lakes, but differ in the feedback mechanisms involved. Despite increasing interest, the phytoplankton development in charophyte- and angiosperm-dominated lakes under different climatic circumstances remains poorly recognized. Each type of lakes was studied in two distant (>500 km apart) regions of Poland, characterized by distinctly different climate features (western – warmer, and north-eastern – cooler), with temperature differences corresponding to the predicted magnitude of the global warming-related temperature rise in the near future. Twelve lakes were selected for this study, three Chara- and three Potamogeton-lakes in each region. In addition to phytoplankton analysis, macrophytes and climatic conditions, water chemistry, and the use of land in the catchment area were studied. Although we expected that climatic differences would have greater impact on the structure of phytoplankton assemblage than that expected due to higher macrophyte biomass and lower nutrient availability in Chara- than in Potamogeton-lakes, multidimensional statistical analyses clearly distinguished between the two macrophyte types of lakes. Significantly lower values of the total phytoplankton biomass, and the biomass of diatoms and cyanobacteria occurred in Chara- vs Potamogeton-lakes. We therefore postulate that not only abundantly developed submerged macrophytes, but also the type of vegetation are important factors structuring phytoplankton development and by interacting with the physical and chemical characteristics of water show potential in mitigating the effects of climate change.

Panarchy suggests why management mitigates rather than restores ecosystems from anthropogenic impact

Panarchy, a model of dynamic systems change at multiple, interconnected spatiotemporal scales, allows assessing whether management influences ecological processes and resilience. We assessed whether liming, a management action to counteract anthropogenic acidification, influenced scale-specific temporal fluctuation frequencies of benthic invertebrates and phytoplankton assemblages in lakes. We also tested whether these fluctuations correlated with proxies of liming (Ca:Mg ratios) to quantify scale-specific management effects. Using an ecosystem experiment and monitoring data, time series analyses (1998–2019) revealed significant multiscale temporal (and thus panarchy) structure for littoral invertebrates across limed and reference lakes. Such patterns were inconsistent for sublittoral invertebrates and phytoplankton. When significant panarchy structure was found, Ca:Mg ratios correlated with only a few of the identified temporal fluctuation frequencies across limed and reference lakes. This suggests that liming effects become diluted in the managed lakes. The lack of manifestations of liming across the independent temporal fluctuation patterns suggest that this lake management form fails to create and enforce cross-scale interactions, a crucial component of ecological resilience. This interpretation supports liming as a mitigation effort rather than a tool to restore acidified lakes to a self-organizing system equivalent of circumneutral references.