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We analysed ground vegetation in 250 plots in 2018 in the old‐growth Picea abies‐dominated forest Säby Västerskog, south‐east Sweden as a follow‐up of studies in 1946 and 1998 with the same layout of plots. The vegetation changes were not clearly directional: the species composition in 2018 was intermediate between that of 1946 and 1998, whereas in 1998 species richness was higher and with the unique presence of a number of species indicating small‐scale disturbances. Vaccinium myrtillus increased in cover since 1946 and Avenella flexuosa decreased. This goes against regional trends that have been attributed to nitrogen deposition. Regional changes are overshadowed by local dynamics. [ABSTRACT FROM AUTHOR]

Understanding the trophic and demographic dynamics of apex predators is of paramount importance for ecosystem conservation. Apex predators are usually free from predation, and thus, the main driver of population dynamics is the availability of trophic resources, which affects breeding performance. Albeit food habits have been described in many apex species, the effects of changes in the trophic niche on long‐term demographic dynamics are poorly known. We describe the long‐term (N = 25 years) changes in trophic niche breadth of a recovering golden eagle population in a Mediterranean landscape (northern Spain) and search for potential correlates with their productivity (i.e., number of fledged eaglets per controlled pair) as a proxy for their breeding performance (N = 290 pair‐years). We identified a total of 3475 prey items from 77 species; rabbits, hares, and red‐legged partridges were the most frequent prey consumed (overall 51%), followed by roe deer (10%), red‐billed chough, red foxes, and woodpigeons, all of them with >5%. Prey diversity in eagles' diet decreased during the study period. Consumption of rabbits and roe deer increased, while that of hares and partridges decreased; no significant trends were observed in the consumption of foxes, choughs, and woodpigeons. Prey diversity and red‐legged partridge consumption were negatively correlated with productivity at the territory level, while rabbits, corvids, and pigeons showed a strong positive relationship with productivity. The size of the territory showed the strongest positive relationship with productivity, while roughness was negatively correlated. Rabbits and ungulates showed negative and positive correlations with roughness, respectively, while predator consumption exhibited a negative relationship with the size of the territory. Our findings give insights into the potential trophic mechanisms driving the dynamics of recovering apex predator populations; a reduction in the trophic niche breadth toward specific groups of prey, which could be due to a higher availability and individual specificity toward these prey species, might enhance productivity at the territory level and, ultimately, influence population dynamics facilitating the recovery process. The remarkable increase in the consumption of wild ungulates, predators, and other apex consumers suggests that the current population recovery and reduced trophic niche breadth may facilitate this eagle population to exhibit its apex role and contribute to ecosystem functionality. [ABSTRACT FROM AUTHOR]

Knowing the impacts of global climate change on the habitat suitability distribution of Limassolla leafhoppers contributes to understanding the feedback of organisms on climate change from a macroecological perspective, and provides important scientific basis for protecting the ecological environment and biodiversity. However, there is limited knowledge on this aspect. Thus, our study aimed to address this gap by analyzing Asian habitat suitability and centroid shifts of Limassolla based on 19 bioclimatic variables and occurrence records. Selecting five ecological niche models with the outstanding predictive performance (Maxlike, generalized linear model, generalized additive model, random forest, and maximum entropy) along with their ensemble model from 12 models, the current habitat suitability of Limassolla and its future habitat suitability under two Shared Socio‐economic Pathways (SSP1‐2.6 and SSP5‐8.5) in the 2050s and 2090s were predicted. The results showed that the prediction results of the five models are generally consistent. Based on ensemble model, 11 potential biodiversity hotspots with high suitability were identified. With climate change, the suitable range of Limassolla will experience both expansion and contraction. In SSP5‐8.52050s, the expansion area is 118.56 × 104 km2, while the contraction area is 25.40 × 104 km2; in SSP1‐2.62090s, the expansion area is 91.71 × 104 km2, and the contraction area is 26.54 × 104 km2. Furthermore, the distribution core of Limassolla will shift toward higher latitudes in the northeast direction, and the precipitation of warmest quarter was found to have the greatest impact on the distribution of Limassolla. Our research results supported our four hypotheses. Finally, this research suggests establishing ecological reserves in identified contraction to prevent habitat loss, enhancing the protection of biodiversity hotspots, and pursuing a sustainable development path with reduced emissions. [ABSTRACT FROM AUTHOR]

Concerns have been raised regarding the degradation of stream water quality due to the excessive influx of atmospheric deposition. This study aimed to reveal the long‐term variation in stream water chemistry in approximately 40 forested small watersheds in the northern Kanto region, based on 3 surveys conducted in 1991–1992, 2006–2007, and 2022. The factors influencing each dissolved element were investigated. Regarding long‐term variations in stream water chemistry, relatively stable concentrations of cations (Ca2+, Mg2+, K+, and Na+) and SiO2 were observed. However, the concentrations of anions (Cl−, NO3−$$ {\mathrm{NO}}_3^{-} $$, and SO42−$$ {\mathrm{SO}}_4^{2-} $$) decreased due to the improvement in the atmospheric environment and the diminishing effect of fertilization. Furthermore, the recent increase in stream water pH was attributed to an increase in bicarbonate (HCO3−$$ {\mathrm{HCO}}_3^{-} $$), compensating for the decrease in anion concentrations relative to cations. Geology was the most significant factor for inter‐watershed variations in cations and SiO2, and this influence remained relatively constant over 30 years. Forest practices, especially fertilization, had a significant effect on Cl− and NO3−$$ {\mathrm{NO}}_3^{-} $$, and contributed to higher concentrations in the fertilized watersheds than in the non‐fertilized watersheds over the 15 years following fertilization. Sulfate deposition was a significant influencing factor for SO42−$$ {\mathrm{SO}}_4^{2-} $$, and the concentration fluctuated under long‐term variations in deposition over the past 30 years. Despite substantial acid deposition in the study area, the absence of stream water acidification could be attributed to the abundant cation supply from bedrock and volcanic ash, which underwent weathering processes. [ABSTRACT FROM AUTHOR]

As one of the major producers of extreme precipitation, mesoscale convective systems (MCSs) have received much attention. Recently, MCSs over several hotpots, including the Sahel and US Great Plains, have been found to intensify under global warming. However, relevant studies on the East Asian rainband, another MCS hotpot, are scarce. Here, by using a novel rain‐cell tracking algorithm on a high spatiotemporal resolution satellite precipitation product, we show that both the frequency and intensity of MCSs over the East Asian rainband have increased by 21.8% and 9.8% respectively over the past two decades (2000–2021). The more frequent and intense MCSs contribute nearly three quarters to the total precipitation increase. The changes in MCSs are caused by more frequent favorable large‐scale water vapor‐rich environments that are likely to increase under global warming. The increased frequency and intensity of MCSs have profound impacts on the hydroclimate of East Asia, including producing extreme events such as severe flooding. Plain Language Summary: Mesoscale convective systems (MCSs), accounting for more than half of the total rainfall in the East Asian rainband, frequently generate high‐impact extreme weather events, such as flooding. In the summer of 2020, large regions of East Asia suffered extensive flooding and damage. Therefore, understanding the long‐term changes of MCSs is crucial to gain insights into how extreme weather may change in the context of global warming. However, compared to several other MCS hotpots, the investigation of long‐term changes of MCSs is scarce over East Asia. Here, based on a high spatiotemporal resolution satellite precipitation product and a novel MCS tracking method, we find that MCSs have become more frequent and intense in the East Asian rainband and accounted for three quarters of the total rainfall increase during 2000–2021. It is further found that increases in atmospheric total column water vapor, which is mainly due to increased temperature caused by anthropogenic forcing, leads to more frequent large‐scale water vapor‐rich environments that are responsible for the intensification of MCSs. As water vapor increases with global warming, it is very likely that MCSs will continue to intensify in this region into the future. Key Points: Mesoscale convective systems (MCSs) have become more frequent and intense in the East Asian rainband over the past two decadesThe significant increase of MCS precipitation accounted for three quarters of the total rainfall increase during 2000–2021The increase of atmospheric total column water vapor, mainly driven by anthropogenic forcing, leads to more favorable environments for MCSs [ABSTRACT FROM AUTHOR]

Heavy summer precipitation over the southern slope of the Tibetan Plateau has dramatic influences on water resources and hydrological disasters in South Asia. It experienced increasing trends over 1979–1996 and decreasing trends over 1996–2022, which are not yet well understood. Here we show observational and numerical evidence that stratospheric ozone has significant impacts on long‐term trends of summer precipitation in this strong convection area. It is found that stratospheric ozone depletion, by modulating the lower stratospheric temperature and upper‐tropospheric static stability, enhances deep convection and precipitation over the southern slope of the Tibetan Plateau. The results suggest that the ozone recovery in the future may reduce the summer precipitation over the southern slope of the Tibetan Plateau in the first half of the 21st century, which would be imperative for future water resource management in South Asia. Plain Language Summary: South Asia, with a population of more than 1.8 billion, is among the most vulnerable regions in the world in response to climate change and a global hotspot for water security. Heavy summer precipitation over the southern slope of the Tibetan Plateau, which directly affects North India and Nepal with a population of more than 200 million and has dramatic influences on water resources and hydrological disasters in South Asia, experienced increasing trends over 1979–1996 and decreasing trends over 1996–2022 (Figure 1). We find that the long‐term variations of the summer precipitation are likely related to the stratospheric ozone depletion and recovery over the Tibetan Plateau in recent decades. The convective precipitation over the southern slope of the Tibetan Plateau is modulated by the upper tropospheric static stability which is affected by the lower‐stratospheric temperature. We find that stratospheric ozone depletion, which radiatively cools the lower stratosphere, enhances the deep convection and precipitation. This work helps to understand the stratospheric contributions to the changes in the summer precipitation over the southern slope of the Tibetan Plateau and future water resource management in South Asia. Key Points: Trends in heavy summer precipitation over the southern slope of the Tibetan Plateau are positive in 1979–1996 and negative in 1996–2022Stratospheric ozone depletion led to lower stratospheric cooling and a reduction of upper‐tropospheric static stabilityStratospheric ozone depletion enhanced the deep convection and precipitation over the southern slope of the Tibetan Plateau [ABSTRACT FROM AUTHOR]

Benthic invertebrates are important trophic links in food webs and useful bioindicators of environmental conditions, but long‐term benthic organism abundance data across broad geographic areas are rare and historic datasets are often not readily accessible. This dataset provides densities of benthic macroinvertebrates collected from 1930 to 2019 during surveys in Lake Erie, a Laurentian Great Lake. The surveys were funded by the governments of the United States and Canada to investigate the status and changes in the benthic community. From the total of 21 lake‐wide and basin‐wide benthic surveys conducted in Lake Erie from 1929 to 2019, we were able to acquire data for 17 surveys, including species‐level data for 10 surveys and data by higher taxonomic groups for seven surveys. Our amassed Lake Erie dataset includes data from 11 surveys (including five with species‐level data) conducted in the western basin in 1930–2019, seven surveys (six with species‐level data) in the central basin, and eight surveys (seven with species‐level data) in the eastern basin (1973–2019). This Lake Erie dataset represents the most extensive temporal dataset of benthic invertebrates available for any of the Laurentian Great Lakes. Benthic samples were collected using Ponar or Shipek bottom dredges and taxa densities were calculated as individuals per square meter using the area of the dredge. Density data are provided for taxa in the Annelida, Arthropoda, Mollusca, Cnidaria, Nemertea, and Platyhelminthes phyla. Current taxonomy was used for most groups but, in a few cases, older taxonomic names were used for consistency with historical data. Analysis of this dataset indicates that eutrophication, water quality improvement, and dreissenid introduction were the major drivers of changes in the benthic community in the western basin, while hypoxia was a major factor in the central basin, and dreissenid introduction was the most important driver in the eastern basin. Considering the rarity of high taxonomic resolution long‐term benthic data for lake ecosystems, this dataset could be useful to explore broader aspects of ecological theory, including effects of eutrophication, hypoxia, invasive species, and other factors on community organization, phylogenetic and functional diversity, and spatial and temporal scales of variation in community structure. In addition, the dataset could be useful for studies on individual species, including abundance and distribution, species co‐occurrence, and how the patterns of dominance and rarity change over space and time. Use of this dataset for academic or educational purposes is encouraged as long as this data paper is properly cited. [ABSTRACT FROM AUTHOR]

A few studies have used historical inland fisheries data for defining reference points necessary for fisheries management. We developed a historical baseline of catches for inland fisheries of Greece during 1928–2019, with the interwar period (1928–1939), a period of intense political and socio‐economic turmoil, serving as a pre‐development reference period. The main harvested species were cyprinids, represented predominantly by Cyprinus carpio and Rutilus rutilus. Species that are currently threatened (i.e., Rutilus ylikiensis/Rutilus panosi and Alosa macedonica) or even possibly extinct (Pelasgus epiroticus) were vital food sources for local populations. Inland catches during the interwar period (1928–1939) were more than double than during 2000–2019, even though the former period can be described as early‐fishery. Such historical data are of high importance because many inland ecosystems were lost during the last century, and thus can be viewed as reference points for future inland fisheries and ecosystem management. [ABSTRACT FROM AUTHOR]

Understanding the degree to which deterministic and stochastic processes drive community assembly is an ongoing focus of research in community ecology. This effort is strongly biased towards ground‐rooted plants, resulting in a limited understanding of communities of other life‐forms, such as structurally dependent plants. Vascular epiphytes are sessile organisms growing non‐parasitically on three‐dimensional dynamic patches, their host plants. Since negative biotic interactions are thought to play a minor role in vascular epiphyte assembly, in some forests, epiphytes are fascinating model organisms to understand the prevalence of environmental filtering in shaping community assembly.We assessed the contribution of deterministic processes on the temporal dynamics of vascular epiphyte assemblages by tracking the direction of changes in composition, species richness and abundance in time at different ecological and spatial scales. We made use of a globally unique dataset from a lowland forest in Panama. We predict that if niche‐based mechanisms dominate, (a) temporal changes will be directional and (b) differences in the species composition of epiphyte assemblages will be primarily related to host plant characteristics and, to a lesser degree, to the distance between host trees.We show that temporal changes in vascular epiphyte assemblages were directional at different ecological scales, such as the forest patch, host species or individual tree assemblages. Epiphyte assemblages on host trees became more similar in their composition over time than expected by chance, and these changes were not due to homogenisation. While host characteristics were related to these directional changes, host structure rather than host identity was more strongly related to variation in assemblage dissimilarity, while spatial distance among trees was of minor importance. The observed directionality was primarily due to environmental filtering.This study provides the first evidence that niche‐based mechanisms dominate the dynamics of vascular epiphyte assemblages. Analysing temporal patterns of vascular epiphyte assemblages is a first important step towards understanding the relative importance of deterministic processes for diversity maintenance of one of the most diverse plant groups in the tropics.Synthesis. Directionality in the temporal changes of epiphyte assemblages suggests that niche‐based mechanisms dominate these temporal changes. Host size over host identity is the most important environmental filter for epiphyte assemblages establishment. [ABSTRACT FROM AUTHOR]

Taxonomic and functional trajectories of benthic assemblages were studied in shallow soft‐bottom sediments in the bay of Saint‐Brieuc (Western English Channel). Changes were assessed at different spatial and temporal scales using a macrobenthic dataset based on 38 stations sampled in 1987 and 2019, coupled with data from one station sampled annually between 2005 and 2019 as part of the European Water Framework Directive monitoring programme.Taxonomic trajectories indicated 1) changes in the structure and distribution of benthic assemblages, 2) an homogenization of the assemblages, and 3) significant functional shifts.Fishing activities and nutrient enrichment are probably strong drivers of the observed changes, as suggested by the higher mortality rate of fragile, flexible, tubiculous and burrowing species, and the increase in the abundance of opportunistic species in the assemblages. Certain populations of macroinvertebrates seem jointly controlled by climate change and by the aforementioned local factors of disturbance.The Community Trajectory Analysis framework appears as a new and interesting method to track ecological changes in marine ecosystems by measuring change with respect to a baseline state, to help define ecological recovery (station returning to the initial ecological state) and departure (station presenting increased changes over time), and to analyse trajectory similarity.According to the degradation of habitat over time, we identify the need for the implementation of knowledge‐based conservation strategies, especially within Natura 2000 sites. [ABSTRACT FROM AUTHOR]

Human inputs of pollutants to the atmosphere and subsequent deposition may decrease pH in the coastal waters. Significant rate of decrease in pH and increase in pCO2 by 3–5 times is noticed in the coastal Bay of Bengal (BoB) than the low‐latitude global ocean trends in the last few decades. We provide evidence for the first time for a rapid decrease in surface water pH due to atmospheric deposition of pollutants in the coastal BoB. The decrease in pH in the coastal BoB over the last decade is associated with concomitant increase in aerosol optical depth (AOD), total suspended particles (TSP) in air, sulfate and nitrate concentrations in TSP. This study suggests that contamination of surface coastal BoB by atmospheric pollutants not only acidifies surface ocean but also potentially amplifies CO2 emission with immediate implications to regional weather and climate. Plain Language Summary: Atmospheric pollutants are being increased rapidly in the South and Southeast Asia. Its deposition on the coastal waters decreases pH more rapidly than CO2 dissolution. We monitored the coastal waters of Bay of Bengal for 12 years at monthly observations and noticed the rate of decrease in pH is 3 times higher than open sea region in the low latitude global ocean and attributed to deposition of pollutants from the atmosphere. Key Points: Long‐term variability in pH suggests rapid acidification of coastal water of Bay of BengalAtmospheric deposition of pollutants decrease coastal water pHRapid rate of increase in atmospheric dust is noticed in the coastal Bay of Bengal [ABSTRACT FROM AUTHOR]

Time series of European sardine (Sardina pilchardus) landings from 1962 and environmental variables from 1978 in the northern Alboran Sea are analysed. European sardine spawns in the northern Alboran Sea from mid‐autumn to late winter at a temperature range slightly higher than the one observed in the nearby Eastern North Atlantic and the North Western Mediterranean. Individuals hatched during autumn and winter are incorporated to the fishery during the following summer and autumn producing the maximum annual landings. These landings show both a decreasing long‐term trend and a strong inter‐annual variability. Although further research is needed, the warming trend of sea surface temperature and the decrease in upwelling intensity inferred from empirical orthogonal function (EOF) analyses could have some influence on the negative trends of sardine landings. The inter‐annual variability of sardine abundance seems to be related to the wind intensity at a local scale, the second principal component of the chlorophyll concentration and the sardine abundance during the preceding year. If the inter‐annual variability is considered, a linear model including these three variables with a one‐year time lag allows to explain 79% of the sardine landings variance. If the negative linear trend is also considered, the model explains 86% of the variance. These results indicate that the body condition of spawners, linked to the food availability during the preceding year, is the main factor controlling the recruitment success. The possibility of predicting sardine landings 1 year in advance could have important implications for fishery management. [ABSTRACT FROM AUTHOR]

It is well established that the ocean is currently losing dissolved oxygen (O2) in response to ocean warming, but the long‐term, equilibrium response of O2 to a warmer climate is neither well quantified nor understood. Here we use idealized multimillennial global warming simulations with a comprehensive Earth system model to show that the equilibrium response in ocean O2 differs fundamentally from the ongoing transient response. After physical equilibration of the model (>4,000 years) under a two times preindustrial CO2 scenario, the deep ocean is better ventilated and oxygenated compared to preindustrial conditions, even though the deep ocean is substantially warmer. The recovery and overshoot of deep convection in the Weddell Sea and especially the Ross Sea after ~720 years causes a strong increase in deep ocean O2 that overcompensates the solubility‐driven decrease in O2. In contrast, O2 in most of the upper tropical ocean is substantially depleted owing to the warming‐induced O2 decrease dominating over changes in ventilation and biology. Our results emphasize the millennial‐scale impact of global warming on marine life, with some impacts emerging many centuries or even millennia after atmospheric CO2 has stabilized. Key Points: Equilibrium response in ocean O2 differs fundamentally from the currently ongoing transient response to global warmingO2 loss in (sub)tropical upper ocean (200–1,000 m) and associated expansion of low O2 zones but O2 increase in deep ocean below 2,000 m on multimillennial timescalesSome impacts on marine life will emerge many centuries after atmospheric CO2 has stabilized [ABSTRACT FROM AUTHOR]

The lifetime of ozone in the troposphere is approximately 3 weeks. Prevailing westerly winds at northern midlatitudes can transport air around the globe in that time. Hence, within these latitudes zonal similarity is expected in long‐term changes and seasonal cycles of concentrations of baseline ozone. We quantify the degree of zonal similarity by examining eight in situ baseline ozone data sets near the west coasts of North America and Europe, that is, upwind of those continents and downwind of the Pacific and Atlantic Oceans, where the impacts of local and regional ozone sources have been largely mixed into the troposphere, giving the best‐defined baseline ozone signature. Zonal similarity is found in both long‐term changes and seasonal cycles. The decades‐long increase in Northern Hemisphere, midlatitude baseline mixing ratios (average ~0.60 ppb year−1 from 1980–2000), has ended, with a maximum reached in the mid‐2000s, followed by slow decrease (average = −0.09 ± 0.08 ppb year−1 from 2000 to the present). The year of the ozone maximum exhibits little if any statistically significant difference with location, altitude, or season. The ozone seasonal cycle differs markedly between sea‐level coastal stations representative of the marine boundary layer and the free troposphere sampled at elevated sites and by sondes and aircraft. However, within each of these broad tropospheric layers, the seasonal cycles are similar at all locations. Vertical profiles of the parameters that define the long‐term trends and the seasonal cycle are also similar between North America and Europe. Plain Language Summary: Ozone in the lower atmosphere (i.e., the troposphere) plays important roles in atmospheric chemistry, air pollution, and climate change. Ozone has a wide variety of sources and sinks that vary temporally and spatially, which complicate our efforts to fully understand ozone's temporal and spatial distribution. Strong sources (primarily man‐made and natural) and sinks of ozone are located in the lower troposphere (i.e., the boundary layer), and input of ozone from the stratosphere is a strong source to the upper troposphere. Here we use long‐term records (~2 decades or more) of measured ozone concentrations at relatively remote locations in the northern midlatitudes (where the majority of man‐made ozone sources are located) to quantify as accurately and precisely as possible ozone's long‐term changes and seasonal cycles. Consistent with the ~3‐week lifetime of ozone in the troposphere, we find substantial similarity in these temporal variations throughout this latitude band. From the start of the measurements in the late 1970s, these concentrations increased until a maximum was reached in the mid‐2000s, followed by slowly decreasing concentrations. Decreasing ozone concentrations in the background troposphere is good news from the perspective of ozone's contributions to urban and regional air pollution and climate change. Key Points: Long‐term changes and seasonal cycles of lower troposphere baseline ozone are similar throughout northern midlatitudesAt northern midlatitudes baseline ozone increased before 2000, but that increase ended, and average concentrations have since decreasedThe year of the baseline ozone maximum (~2006) does not vary significantly with location, altitude, or season [ABSTRACT FROM AUTHOR]

A review of the long‐term changes and variations in benthic communities and the current status of the marine invasive species (MIS) in shallow waters of the Yellow Sea (Chinese sector) and the Sea of Japan (Russian and partly Korean sectors) is presented. This paper reflects on the progress and lessons learned, recommending actions for the future about the conservation of biodiversity.In the Bohai Sea, the benthic ecosystem has been degenerating due to anthropogenic activities such as overfishing and pollution since the 1950s. The dominant position of K‐strategy species is gradually being lost and replaced by R‐strategy species. In the Yellow Sea, the macrobenthic community is different from other areas due to the Yellow Sea Cold Water Mass. Many economic species have been destroyed, and the biotic structure has changed significantly due to overfishing and climate change.In the Russian sector of the Sea of Japan, the macrobenthic communities in the shallow‐water soft bottom have generally been in a stable condition for the last decades, except for some heavily polluted or disturbed areas due to dredging operations. The abundance of select large invertebrate species has changed considerably due to commercial fishing and poaching. Variations in macro‑ and meiobenthic communities under aquaculture conditions have occurred on a local scale during the last five decades.MIS show obvious differences between China and Russia in the following aspects: introduction pathways of MIS, composition and number of non‐native species, threats and impacts of MIS to native communities and ecosystems, and economic and public health impacts.Long‐term monitoring programmes should be developed to reveal future biotic changes and to separate the effects of cyclic variations of benthic communities from the impacts of pollution and eutrophication. Standardization of sampling procedures is required to compare changes/alternations in benthos across various regions worldwide. [ABSTRACT FROM AUTHOR]

Bay Sivash was a hypersaline lagoon but after construction of the North Crimean canal, it shifted to a brackish water state. In 2014, the canal was closed; a salinity increase started. In 2018 and 2019, plankton sampling was conducted in the bay at salinity from 30 to 100 g/L. A decrease in taxonomic diversity and total abundance was observed. Before November of 2018, Harpacticoida and chironomid larvae were the most common and abundant groups. Different stages of Artemia were consumed by invertebrate predators and fish at that time. In November 2018, Artemia stages contributed more than 90% to total zooplankton abundance at all sites excepting with salinity lower than 55 g/L. In June–July 2019, adult Artemia were at all sites with salinity higher than 82 g/L when there was no suppression by predators. A self‐sustaining Artemia population in the bay may recover in 2 or 3 years, when the average salinity would reach 80–90 g/L; total abundance of the active Artemia stages may reach 3000–5000 ind. M−3 between April and August. The lagoon may become one of the world main habitats of Artemia having a significant impact to provide world's supply by its cysts. [ABSTRACT FROM AUTHOR]

Increases in phytoplankton biomass have been widely observed over the past decades, even in lakes experiencing nutrient reduction. However, the mechanisms giving rise to this trend remain unclear. Here, we unveil the potential mechanisms through quantifying the relative contribution of bottom–up versus top–down control in determining biomasses of phytoplankton assemblages in Lake Geneva. Specifically, we apply nonlinear time series analysis, convergent cross mapping (CCM), to decipher the degree of bottom–up versus top–down control among phytoplankton assemblages via quantifying 1) causal links between environmental factors and various phytoplankton assemblages and 2) the relative importance of bottom–up, top–down, and environmental effects. We show that the recent increase in total phytoplankton biomass, albeit with phosphorus reduction, was mainly caused by a particular phytoplankton assemblage which was better adapted to the re‐oligotrophicated environment characterized by relatively low phosphorus concentrations and warm water temperature, and poorly controlled by zooplankton grazing. Our findings suggest that zooplankton act as a critical driver of phytoplankton biomass and strongly impact the dynamics of recovery from eutrophication. Therefore, our phytoplankton assemblage approach in combination with causal identification of top–down versus bottom–up controls provides insights into the reason why phytoplankton biomass may increase in lakes undergoing phosphorus reduction. [ABSTRACT FROM AUTHOR]

Nearshore wave characteristics and its variations at Ganpatipule coast, eastern Arabian Sea, for the past 4 decades (1979–2016) have been examined. The study is based on European Centre for Medium‐Range Weather Forecasts Re‐Analysis‐Interim wave data at ~50 m water depth and the nearshore wave parameters estimated using the numerical model Simulating WAves Nearshore, executed from the Delft3D dashboard considering shallow water wave propagation, wave setup, and breaking. The littoral drift is estimated based on bulk transport formula of the Coastal Engineering Research Centre with the input from the hydrodynamic module. The model shows good agreement with wave rider buoy measured wave parameters at 14‐m water depth. Anomalies of breaker height, period, and direction vary in the range of −0.35–0.4 m, −0.80–1 s, and − 16 to 12°, respectively during the study period. A detailed analysis of monthly variations of breaker height along the study region suggests a significant increasing trend during the Asian summer monsoon, whereas a decreasing trend is identified during the nonmonsoon period. The study region accounts for a northerly net transport of 3.9 × 105 m3 yr−1 with a significant increasing trend of 1,840 m3 yr−1. The strong wind field region along the central Arabian Sea (65–70°E and 15–20°N) gives a strengthened positive correlation (r > 0.7) with the littoral drift. Impacts of Pacific climate variability on interannual and decadal timescales are observed in the littoral drift rates. Key Points: Investigates nearshore wave climate and littoral drift for past 4 decades (1979–2016) at a location in eastern Arabian SeaBreaker height shows a significant increasing trend during the Asian Summer monsoon (June‐September)An increasing trend in the net littoral drift is observed (1,840 m3 yr−1)Impact of Pacific climate variability on littoral drift is observed during 1979–1989 [ABSTRACT FROM AUTHOR]

We present midlatitude solar response and linear trend from Colorado State University/Utah State University Na lidar nocturnal temperature observations between 1990 and 2017. Along with the nightly mean temperatures (_Ngt), we also use the corresponding 2‐hr means centered at midnight (_2MN), resulting in vertical trend profiles similar in shapes as those previously published. The 28‐year trend from _Ngt (_2MN) data set starts from a small warming at 85 km, to cooling at 87 (88) km, reaching a maximum of 1.85 ± 0.53 (1.09 ± 0.74) at 92 (93) km and turns positive again at 102 (100) km. The 6‐month winter trend is much cooler than the 4‐month summer trend with comparable solar response varying around 5 ± 1 K/100 SFU throughout the profile (85–105 km) with higher summer values. We explore the observed summer/winter trend difference in terms of observed gravity wave heat flux heating rate at a nearby station and the long‐term trend of gravity wave variance at a midlatitude. Between 89 and 100 km, the lidar trends are within the error bars of the Leibniz Middle Atmosphere (LIMA) summer trends (1979–2013), which are nearly identical to the lidar‐Ngt trend. We address the need of long data set for reliable analysis on trend, the extent of trend uncertainty due to possible tidal bias, the effect of a Pinatubo/episodic function, and the impact of stratospheric ozone recovery. Plain Language Summary: Anthropogenic greenhouse gases, primarily CO2, alter the Earth's climate, causing warming in the troposphere and the Earth/ocean surface, and cooling in the middle and upper atmosphere. Although determination of the long‐term temperature trend in the important mesopause region, about 100 km from Earth surface where the annual mean temperature is lowest, from ground is very challenging, it has been measured using fluorescence lidar observations. Based on 28‐year (1990–2017) data sets of nightly means and 2‐hr means centered at midnight, the maximum cooling rates in a midlatitude mesopause region are 1.85 K/decade and 1.09 K/decade, respectively, with the latter thought to be relatively free from contamination by atmospheric tides. The winter trend is much cooler than the summer trend. We found good agreement in the summer trend with model prediction and the summer/winter difference correlate with the associated gravity wave heat flux convergence. Key Points: We deduced long‐term solar response and linear trend from 28 years lidar observed midlatitude mesopause region nocturnal temperaturesWe compared the linear trends between nightly mean and 2‐hr midnight mean temperatures, and those between all, 4‐month summer and 6‐month winterWe found good agreement and trend model prediction and correlation between the summer/winter difference and the associated gravity wave heat flux convergence [ABSTRACT FROM AUTHOR]

Aim: Ecological communities are composed of both species and the biotic relationships (interactions or spatial associations) among them. Biotic homogenization in species composition (i.e., increased site‐to‐site similarity) is recognized as a common consequence of global change, but less is known about how the similarity of species relationships changes over space and time. Does homogenization of species composition lead to homogenization of species relationships or are the dynamics of species relationships decoupled from changes in species composition? Location: Wisconsin, USA. Time period: 1950–2012. Major taxa studied: Vascular plants. Methods: We used long‐term resurvey data to analyse changes in plant species association patterns between the 1950s and 2000s at 266 sites distributed among three community types in Wisconsin, USA. We used species associations (quantified via local co‐occurrence patterns) to represent one type of relationship among species. Species pairs that co‐occur more or less than expected by chance have positive or negative associations, respectively. We then measured beta diversity in both species composition and species association networks over time and space. Results: Shifts in species associations consistently exceeded the shifts observed in species composition. Less disturbed forests of northern Wisconsin have converged somewhat in species composition but little in species associations. In contrast, forests in central Wisconsin succeeding from pine barrens to closed‐canopy forests have strongly homogenized in both species composition and species associations. More fragmented forests in southern Wisconsin also tended to converge in species composition and in the species' negative associations, but their positive associations diverged over the last half century. Species composition and associations are generally affected by a similar set of environmental variables. Their relative importance, however, has changed over time. Main conclusions: Long‐term shifts in species relationships appear to be decoupled from shifts in species composition despite being affected by similar environmental variables. [ABSTRACT FROM AUTHOR]

Questions Have compositional changes occurred in thermophilous oak forests in Poland during the past two decades? What kinds of drivers might be responsible for these changes? Are the thermophilous oak woods still rich in species or have they rather lost their diversity? Location Sudetes Mts., SW Poland. Methods The vegetation of thermophilous oak forests within four distinct areas was surveyed on 92 semi-permanent plots in the time periods from 1992 to 1994 and from 2010 to 2014. The overall pattern in vegetation changes, trends in species composition and site parameters, as well as the diversity of studied communities were analysed using ordination and permutation techniques. Results The species composition of thermophilous oak forests has changed significantly. We recorded a decrease in the share of oligotrophic light-demanding species, whereas mesotrophic light-demanding and nitrophilous species showed an upward trend. Regarding the fourth group of shade-tolerant species, their share varied depending on the site. The analysis of habitat parameters revealed that the studied oak forest communities generally shifted from communities of moderately oligotrophic and mesic character towards forests growing on nutrient-richer but drier habitats. Interestingly, the observed change in species composition was not accompanied by the loss of biodiversity that has generally been reported in other types of thermophilous forests in Europe. Conclusions Changes observed within thermophilous and previously coppiced oak forests of southwest Poland are going in a direction which has not been recognized so far in analogous communities. The transition of studied communities is probably a result of the cumulative influence of several drivers, the most crucial of which seem to be soil regeneration, after the period of intensive acidity caused by sulphur emission between 1960 and 2000, and decreasing moisture. The observed changes are independent of the type of forest management (or the lack thereof) within the study sites. [ABSTRACT FROM AUTHOR]

Selective harvest may lead to rapid evolutionary change. For large herbivores, trophy hunting removes males with large horns. That artificial selection, operating in opposition to sexual selection, can lead to undesirable consequences for management and conservation. There have been no comparisons of long-term changes in trophy size under contrasting harvest pressures. We analyzed horn measurements of Stone's rams ( Ovis dalli stonei) harvested over 37 years in two large regions of British Columbia, Canada, with marked differences in hunting pressure to identify when selective hunting may cause a long-term decrease in horn growth. Under strong selective harvest, horn growth early in life and the number of males harvested declined by 12% and 45%, respectively, over the study period. Horn shape also changed over time: horn length became shorter for a given base circumference, likely because horn base is not a direct target of hunter selection. In contrast, under relatively lower hunting pressure, there were no detectable temporal trends in early horn growth, number of males harvested, or horn length relative to base circumference. Trophy hunting is an important recreational activity and can generate substantial revenues for conservation. By providing a reproductive advantage to males with smaller horns and reducing the availability of desirable trophies, however, excessive harvest may have the undesirable long-term consequences of reducing both the harvest and the horn size of rams. These consequences can be avoided by limiting offtake. [ABSTRACT FROM AUTHOR]

ABSTRACT The Arabian Sea and Bay of Bengal (BoB) regions are special interested sea areas in the Northern Hemisphere with large seasonal variability. This study focused on the long-term wind and wave in the central BoB from 1979 to 2012 based on the ECMWF ERA-Interim reanalysis data sets. Data were validated with the nearest available buoy data for the years 2003, 2004 and 2005, and good correlation was observed (root mean square error ≈ 0.17-0.43 m). A clear seasonality was noted with intensified wind and waves during the southwest monsoon season. We observed statistically declining trends in the mean and extreme wind speed (90th percentile) with increasing trend in extreme significant wave height (SWH). Seasonal analysis also investigated and found that the stronger events/winds during the southwest (SW) monsoon season are weakening. Conflicting trends in the wind and wave height were mainly due to the swell dominance at the region which was identified by the separate trend analysis of wind-sea and swell height. The area average analysis is carried out to investigate the sensitivity of the identified trend results for the point location and found similar trends for extreme wind speed and SWH. The high (>5 m) annual maximum SWH in the study area was attributed to the influence of tropical cyclones in the BoB, and all of these high waves occurred before 1996 indicating that the influence of tropical cyclones in the study area decreased after 1996. [ABSTRACT FROM AUTHOR]

Light in the marine environment is a key environmental variable coupling physics to marine biogeochemistry and ecology. Weak light penetration reduces light available for photosynthesis, changing energy fluxes through the marine food web. Based on published and unpublished data, this study shows that the central and southern North Sea has become significantly less clear over the second half of the 20th century. In particular, in the different regions and seasons investigated, the average Secchi depth pre-1950 decreased between 25% and 75% compared to the average Secchi depth post-1950. Consequently, in summer pre-1950, most (74%) of the sea floor in the permanently mixed area off East Anglia was within the photic zone. For the last 25+ years, changes in water clarity were more likely driven by an increase in the concentration of suspended sediments, rather than phytoplankton. We suggest that a combination of causes have contributed to this increase in suspended sediments such as changes in sea-bed communities and in weather patterns, decreased sink of sediments in estuaries, and increased coastal erosion. A predicted future increase in storminess (Beniston et al., 2007; Kovats et al., 2014) could enhance the concentration of suspended sediments in the water column and consequently lead to a further decrease in clarity, with potential impacts on phytoplankton production, CO2 fluxes, and fishery production. [ABSTRACT FROM AUTHOR]

An unusual data set of Plecoptera, very sensitive aquatic insects, allow diversity changes to be estimated for 175 streams in the Czech Republic between two periods, 1955-1960 and 2006-2011., Substantial overall declines in Plecoptera biodiversity were found. Three-quarters of the species studied declined in their frequency of occurrence, 48% of which were estimated have undergone a reduction of >30%. Overall, streams either at lowland or submontane altitude, particularly large rivers, lost the most species. A significant decrease in local species biodiversity was found in streams up to 700 m a.s.l., especially in small rivers., The taxonomic dissimilarity between contemporary and previous assemblages increased from montane to lowland altitudes (from ˜30 to ˜70%) and was the same in streams of different size (˜50%). Partitioning of dissimilarity showed that the overall change in dissimilarity was primarily driven by changes in species richness; however, species replacement was not negligible., The results demonstrated that aquatic insect biodiversity (Plecoptera in particular) is substantially declining in Europe, probably to a similar or greater extent than terrestrial insects, with potential implications for biodiversity of running waters. Plecoptera showed a complex response to habitat change, including loss of pollution-sensitive species and habitat-specialists as well as common species, which, in some cases, counterbalanced their losses by concurrent colonisation of new sites. [ABSTRACT FROM AUTHOR]

Populations may potentially respond to climate change in various ways including moving to new areas or alternatively staying where they are and adapting as conditions shift. Traditional laboratory and mesocosm experiments last days to weeks and thus only give a limited picture of thermal adaptation, whereas ocean warming occurring over decades allows the potential for selection of new strains better adapted to warmer conditions. Evidence for adaptation in natural systems is equivocal. We used a 50-year time series comprising of 117 056 samples in the NE Atlantic, to quantify the abundance and distribution of two particularly important and abundant members of the ocean plankton (copepods of the genus Calanus) that play a key trophic role for fisheries. Abundance of C. finmarchicus, a cold-water species, and C. helgolandicus, a warm-water species, were negatively and positively related to sea surface temperature ( SST) respectively. However, the abundance vs. SST relationships for neither species changed over time in a manner consistent with thermal adaptation. Accompanying the lack of evidence for thermal adaptation there has been an unabated range contraction for C. finmarchicus and range expansion for C. helgolandicus. Our evidence suggests that thermal adaptation has not mitigated the impacts of ocean warming for dramatic range changes of these key species and points to continued dramatic climate induced changes in the biology of the oceans. [ABSTRACT FROM AUTHOR]

The plant community structure of European lowland forests has changed dramatically in the twentieth century, leading to biodiversity decline at various spatial scales. However, due to methodological difficulties associated with simultaneous changes in species diversity and composition, ecological processes behind the changes are still poorly understood., We analysed temporal changes in forest plant community after the mid-twentieth-century abandonment of coppicing in a typical Central European forest, which had been managed as coppice for centuries. We used 122 semi-permanent plots first surveyed in the 1950s shortly after the last coppicing and again in the 2000s after half a century of natural succession. We used a novel temporal nestedness analysis to disentangle the immigration and extinction processes underlying temporal changes in community structure and tested whether species gains and losses were ecologically random. , The studied vegetation has shifted from the species-rich assemblages of a relatively open and low-nutrient forest towards the impoverished flora of a closed-canopy forest dominated by a few shade-adapted species. The significant reduction in beta diversity, that is, compositional heterogeneity among plots, indicated taxonomic homogenization of the forest understorey. Temporal species turnover was only a minor component of the community change, and recent assemblages are nested subsets of the former ones. Ecologically non-random extinctions dominated these changes. Light-demanding species with a persistent seed bank were the most prone to extinction, while species with high specific leaf area substantially increased in frequency., Synthesis and applications. The dominant process after the abandonment of coppicing was the ecologically non-random extinction of light-demanding species, leading to an impoverished, temporally nested plant community structure. This development is typical for many abandoned coppices and poses a significant threat to forest biodiversity in Europe. If forestry and conservation policies continue to prefer closed-canopy stands, many endangered species are likely to pay their extinction debts. To restore declining or even locally extinct species, canopy opening in abandoned coppices is urgently needed. [ABSTRACT FROM AUTHOR]

1. Rapid expansion and intensification of anthropogenic activities in the 20th century has caused profound changes in freshwater assemblages. Unfortunately, knowledge of the extent and causes of species loss (SL) is limited due to the lack of reliable historical data. An unusual data set allows us to compare changes in the most sensitive of aquatic insect orders, the Plecoptera, at some 170 locations in the Czech Republic between two time periods, 1955-1960 and 2006-2010. Historical data (1890-1911) on assemblages of six lowland rivers allow us to infer even earlier changes. 2. Regional stonefly diversity decreased in the first half of the 20th century. Streams at lower altitudes lost a substantial number of species, which were never recovered. In the second half of the century, large-scale anthropogenic pressure caused SL in all habitats, leading to a dissimilarity of contemporary and previous assemblages. The greatest changes were found at sites affected by organic pollution and a mixture of organic pollution and channelisation or impoundment. Colonisation of new habitats was observed in only three of the 80 species evaluated. 3. Species of moderate habitat specialisation and tolerance to organic pollution were most likely to be lost. Those with narrow specialisations in protected habitats were present in both historical and contemporary collections. 4. Contemporary assemblages are the consequence of more than a 100 years of anthropogenic impacts. In particular, streams at lower altitude and draining intensively exploited landscapes host a mere fragment of the original species complement. Most stonefly species are less frequently present than before, although their assemblages remain almost intact in near-natural mountain streams. Our analyses demonstrate dramatic restriction of species ranges and, in some cases, apparent changes in altitudinal preference throughout the area. [ABSTRACT FROM AUTHOR]

J. Neurochem. (2012) 121, 597-606. Abstract In cultured rat neocortical interneurons, we have studied the effect of long-term application of NMDA or AMPA on the surface density of the NMDA (GluN) receptor subunits GluN1 and GluN2B. Stimulation of Ca2+-permeable AMPA (GluA) receptors located on the interneurons decreased the response of GluN receptors. The reduction was caused by a decrease in the surface density of GluN1/GluN2B subunits. In contrast, stimulation of GluN receptors located on the interneurons enhanced the surface density of GluN1/GluN2B subunits. Both effects could be induced by network activation. [ABSTRACT FROM AUTHOR]

J. Neurochem. (2012) 121, 587-596. Abstract Changes in the density of NMDA (GluN) receptors in the neuronal membrane are critical for plasticity, whereas malfunction of precisely regulated GluN receptor activity may be involved in neurotoxicity. In cultured rat neocortical interneurons, we have studied the regulation of the surface density of GluN1, GluN2A and GluN2B subunits. Application of 5 μMol NMDA for 24 h followed by a washout period of 24 h decreased the response of GluN receptors for at least 2 days. The reduction was caused by a decrease in the surface density of GluN1/GluN2B subunits, whereas GluN2A subunits remained unaffected. Our data indicate that long but reversible low level activation of GluN receptors can cause long-term changes in their subunit composition in cultured interneurons. [ABSTRACT FROM AUTHOR]

Aim Lowland woodlands in Europe went through dramatic changes in management in the past century. This article investigates the influence of two key factors, abandonment of coppicing and increased pressure of ungulates, in thermophilous oakwoods. We focused on three interconnected topics: (1) Has the assumed successional trend lead to impoverishment of the vegetation assemblages? (2) Has it resulted in vegetation homogenization? (3) Are the thermophilous oakwoods loosing their original character? Location Czech Republic, Central Europe. Methods The vegetation in 46 semi-permanent plots was recorded three times: firstly, shortly after the abandonment of coppicing (1953) and then, after four to six decades of secondary succession and strong game impact (1992 and 2006). Overall trends and changes in species spectra were analysed. Results There is a marked successional shift towards species-poorer communities growing in cooler, moister and nutrient-richer conditions. The change was significantly different in parts affected and unaffected by high numbers of ungulates yet only for herbs, not the woody species. However, observed change in species composition was not accompanied by significant homogenization process that is the general process reported from elsewhere. A sharp decline in plant species typical for thermophilous woodland communities and in endangered species indicates that the original character of the woodland has been gradually lost. Main conclusions Thermophilous oakwoods have been largely replaced by mesic forests. Lowland oakwoods in continental parts of Europe historically depended on active management, which kept the understorey conditions light and warm. Successional processes in the 20th century caused a critical loss of species diversity at various spatial levels. However, artificially high numbers of ungulates, which otherwise have a negative impact, probably held up succession, so that the changes may still be reversible. [ABSTRACT FROM AUTHOR]

Background: Evaluations of continuous subcutaneous insulin infusion (CSII) usually focus on one pre- and one post-CSII measurement to assess metabolic therapy outcome. Aim: Extending this research, the aim of the present study was to provide a more fine-grained analysis of achieved glycaemic control. Methods: In 52 patients with type 1 diabetes (mean age of 37.85 years at CSII begin; s.d. ± 12.41), haemoglobin A1c (HbA1c) levels were assessed every 3 months over a period of 5 years (1 year before and 4 years after the introduction of CSII). Mixed models were utilized to describe changes in glycaemic control. Results: The pre–post course showed that already in the first quarter, a statistically significant lower HbA1c level was obtained [7.30%, in contrast to 8.21% at the last quarter with intensified conventional therapy (ICT)]. In the following 15 quarters, the mean HbA1c levels remained constantly lower than that with ICT. Overall, the aggregated mean HbA1c level of patients with CSII therapy was 7.19%, in contrast to 8.08% with ICT; thus, an overall decrease by 11% was achieved. In addition, individual differences in blood glucose level and age of diabetes onset as a predictor for therapy success were analysed. Conclusions: The data show an immediate, stable and long-term effect of CSII on HbA1c. In addition, a significant relationship between metabolic control and age of diabetes onset was found, as well as a reduction of variance in HbA1c levels between subjects after change to CSII. [ABSTRACT FROM AUTHOR]

The spatial extent of small pelagic fish spawning habitat is influenced by environmental factors and by the state of the adult population. In return, the configuration of spawning habitat affects recruitment and therefore the future structure of the adult population. Interannual changes in spatial patterns of spawning reflect variations in adult population structures and their environment. The present study describes the historical changes in the spatial distribution of spawning of anchovy ( Engraulis encrasicolus) and sardine ( Sardina pilchardus) in the Bay of Biscay during two periods: 1967–72 and 2000–2004. Using data from egg surveys conducted in spring, the spatial distributions of anchovy and sardine eggs are characterized by means of geostatistics. For each survey, a map of probability of egg presence is constructed. The maps are then compared to define (1) recurrent spawning areas, (2) occasional spawning areas and (3) unfavourable spawning areas during each period. Sardine spawning habitat is generally fragmented and appears spatially limited by the presence of cold bottom water. It is confined to coastal or shelf break refuge areas in years of restricted spawning extent. For anchovy, recurrent spawning sites are found in Gironde and Adour estuaries whilst spawning can extend further offshore in years of more intense spawning. For both species, the mean pattern of spawning has changed between 1967–72 and 2000–2004. Noticeably, the spatial distribution of anchovy eggs in spring has expanded northward. This trend possibly results from changes in environmental conditions during the last four decades. [ABSTRACT FROM AUTHOR]

1. In an attempt to discern long-term regional patterns in phytoplankton community composition we analysed data from five deep peri-alpine lake basins that have been included in long-term monitoring programmes since the beginning of the 1970s. Local management measures have led to synchronous declines in phosphorus concentrations by more than 50% in all four lakes. Their trophic state now ranges from mesotrophic to oligotrophic. 2. No coherence in phytoplankton biomass was observed among lakes, or any significant decrease in response to phosphorus (P)-reduction (oligotrophication), except in Lakes Constance and Walen. 3. Multivariate analyses identified long-term changes in phytoplankton composition, which occurred coherently in all lakes despite the differing absolute phosphorus concentrations. 4. In all lakes, the phytoplankton species benefiting from oligotrophication included mixotrophic species and/or species indicative of oligo-mesotrophic conditions. 5. A major change in community composition occurred in all lakes at the end of the 1980s. During this period there was also a major shift in climatic conditions during winter and early spring, suggesting an impact of climatic factors. 6. Our results provide evidence that synchronous long-term changes in geographically separated phytoplankton communities may occur even when overall biomass changes are not synchronous. [ABSTRACT FROM AUTHOR]

Abstract Long-term change in zooplankton biomass and composition of major zooplankton assemblages was studied with a focus on climate change and squid catch in the Japan/East Sea. This study deals with data sets of zooplankton biomass, abundance of major zooplankton assemblages, and sea surface temperature (SST) obtained during the period from 1965 to 1998, and the catch of squid, Todarodes pacificus , from 1978 to 1998. Based on its physical characteristics, the study area was divided into two subregions, a northern and southern region. The SST during the winter and spring (February and April) steadily increased after the late 1980s in the southern region. On the other hand, the northern region did not have a warm winter and had higher interannual fluctuations. Zooplankton biomass also showed an increasing trend and major zooplankton assemblages have shifted in their composition since the early 1990s. The northern region exhibited a greater increasing trend than the southern region in zooplankton biomass. Macrozooplankton such as chaethognaths, euphausiids and amphipods gradually increased after the early 1990s. In the Japan/East Sea, squid catches increased continuously after the early 1990s. The squid catch for the autumn of year n is significantly associated with the zooplankton biomass collected in October and December of year n - 1 (r =0.864 in the northern region and r =0.818 in the southern region, P < 0.001) and macrozooplankton, especially euphausiids (r =0.578 in the northern region and r =0.840 in the southern region, P < 0.05) and amphipods (r =0.695 in the northern region and r =0.648 in the southern region, P < 0.05). [ABSTRACT FROM AUTHOR]

Abstract Long-term phytoplankton responses in Lake Geneva to a decline in phosphorus (P) loading are examined in terms of summer (July–September) biomass and community structure. With the rapid development of human activity on its banks and within its catchment area in the 1960s, this large subalpine hydrosystem shifted from oligotrophy to eutrophy within approximately one decade. Measures to reduce P loading were initiated successfully in the mid-1970s, when total P concentrations in the winter overturn altered from 90 μg/L in 1980 to 40 μg/L in 1998. Until the 1990s, algal descriptors improved as expected (biomass decline, reappearance of diatom species, increased contribution of nanoplankton). Then, paradoxically, and in contrast to the reappearance of oligotrophic species, summer algal biomass began to increase. Pre-summer (period prior to the beginning of the clear water phase) dissolved inorganic phosphorus concentrations and summer phytoplankton composition presented similar interannual trends. However, the succession of phytoplankton structure during the reoligotrophication phase differed greatly from that during the eutrophication period, and a recent abnormal upward trend in algal densities is mainly the result of the development of large species that formerly were only common from late September until November. This community change, mainly triggered by filamentous (Mougeotia gracillima, Tribonema ) or motile forms (Dinobryon sociale, Cryptophycea ), seems to have been induced by the earlier and greater deepening of the P-depleted layer. In addition to milder summers, this massive development of larger forms seems to be favoured by four of their biological features: tolerance to warm temperatures, tolerance to low-light intensity (might exploit deeper layers where P is not yet limiting), shapes not only providing a large surface to volume ratio or motility (adaptation to low-nutrient concentrations), but increasing resistance to... [ABSTRACT FROM AUTHOR]

We examined long-term changes in the macroalgal vegetation at Stora Bornö Island in the inner Gullmar Fjord on the Swedish Skagerrak coast. This was made possible by access to a 1941 diving investigation. The same sites were reinvestigated in 1998. Community composition and depth distributions of species were compared and changes were analyzed with focus on functional groups (size, thallus shape, and life-history traits). We discovered a significant decrease in the depth extension of macroalgal species and a dramatic decline of species richness in the lower littoral (below 16 m of depth) compared with 57 years earlier. Ordination analysis revealed that there was a significant difference in the community composition between the two study periods. In general, small (<10 cm), thin, filamentous, and aseasonal ephemerals increased in relative abundance, whereas larger (>10 cm), coarsely branched, and perennial algae decreased. Calibrations of individual species to local sediment cover, using canonical correspondence analysis, indicated that part of the change in species composition was related to sediment load. Furthermore, large-scale climate differences (NAO Winter Index) between the study periods indicated a higher impact of Baltic Sea and Kattegat water in the nutrient dynamics of the fjord in the 1998 study. We concluded that the observed long-term changes in the macroalgal community at Stora Bornö Island were consistent with an increased nutrient availability. [ABSTRACT FROM AUTHOR]

We examined long-term changes in the macroalgal vegetation at Stora Bornö Island in the inner Gullmar Fjord on the Swedish Skagerrak coast. This was made possible by access to a 1941 diving investigation. The same sites were reinvestigated in 1998. Community composition and depth distributions of species were compared and changes were analyzed with focus on functional groups (size, thallus shape, and life-history traits). We discovered a significant decrease in the depth extension of macroalgal species and a dramatic decline of species richness in the lower littoral (below 16 m of depth) compared with 57 years earlier. Ordination analysis revealed that there was a significant difference in the community composition between the two study periods. In general, small (<10 cm), thin, filamentous, and aseasonal ephemerals increased in relative abundance, whereas larger (>10 cm), coarsely branched, and perennial algae decreased. Calibrations of individual species to local sediment cover, using canonical correspondence analysis, indicated that part of the change in species composition was related to sediment load. Furthermore, large-scale climate differences (NAO Winter Index) between the study periods indicated a higher impact of Baltic Sea and Kattegat water in the nutrient dynamics of the fjord in the 1998 study. We concluded that the observed long-term changes in the macroalgal community at Stora Bornö Island were consistent with an increased nutrient availability. [ABSTRACT FROM AUTHOR]

1. The long-term changes (1956–1998) in density and species composition of planktonic rotifers were studied at two sampling stations (I, II) of Lake Donghu, a shallow eutrophic Chinese Lake densely stocked with filter-feeding fishes. Annual average densities of rotifers increased with an increase in fish yield and eutrophication, whilst species number decreased from 82 in 1962–1963 to 62 in 1994–1998. 2. During 1962–98, some species such as Anuraeopsis fissa, Polyarthra spp. (including P. dolichoptera & P. vulgaris), Trichocerca pusilla and Synchaeta oblonga increased their percentage in abundance remarkably, whilst the proportion of Keratella cochlearis decreased at two relatively eutrophic stations from 19 to 4.2% at Station I and from 30 to 3.2% at Station II. 3. The high rmax of A. fissa probably made it more successful than other rotifers under high predation pressure by planktivorous fish. The decrease in the K. cochlearis population might be attributed partly to predation by Cyclops vicinus. 4. Small rotifers were less vulnerable to fish predation than large-sized cladocerans. Decreases in cladocerans coincided with increases in rotifers, suggesting that the indirect effect of fish predation on cladocerans might have partly contributed to the population development of rotifers in Lake Donghu during recent decades. 5. We also conducted surveys (1994–1998) of seasonal dynamics of rotifers at four sampling stations (I–IV) which have varied in trophic status after fragmentation of the lake in the 1960s. A total of 75 species were identified at the four stations. Both densities and biomass of rotifers were considerably higher in the two more eutrophic stations than in the two less eutrophic stations. This indicates that the population increase of rotifers at Stations I and II during recent decades might be partly attributed to eutrophication of the lake water. [ABSTRACT FROM AUTHOR]

Abstract Lake Abashiri is an example of a meromictic lake under the stability of upper oligohaline water and lower polyhaline water, but a brackish lake on the whole. Nevertheless, boundary depth of the hypolimnetic layer has gradually decreased with time. At the same time, this has led to an increase in salinity and eutrophication in the epilimnion and to an acceleration of deoxygenation of the hypolimnion, attributed to the upwelling of bluish water. In order to investigate succession of the aquatic biota linked to these hydrological changes, results of occasional long-term studies on the distribution of plankton and benthos were summarized, mostly from Japanese publications of lake surveys. In each result, the boundary of the polyhaline hypolimnetic layer has gradually risen from 13 to 7 m depth between 1932 and 1955, and has been determined, in recent years, to be 5.5 m. Salinity of the epilimnion was lower than 0.1‰ in 1930s, and 0.5–0.6‰ in the 1940s before 1949. Thereafter, salinity increased to 1.8–2.3‰ until recently, with levels now often over 3‰. Following these hydrological changes, the succession of planktonic fauna and flora, particularly of the dominant species, has exhibited a gradual change from freshwater to brackish or salinity tolerant species during the 72 year period from 1926 to 1997, including a period of variable species composition in 1975–1980 and a period of degradation after that. In contrast, according to available data, the benthic community has remained unchanged in terms of the composition of dominant species in all habitats during the same 72 year period. The dominance of some plankton and benthos species has been maintained over several decades, although the community structures have displayed a few phases of abundance and regression during these 72 years. [ABSTRACT FROM AUTHOR]

Benthic invertebrates are important trophic links in aquatic food webs and serve as useful bioindicators of environmental conditions because their responses integrate the effects of both water and sediment qualities. However, long‐term data sets for benthic invertebrate assemblages across broad geographic areas are rare and, even if collected, historic data sets are often not readily accessible. This data set provides densities of benthic macroinvertebrates for all taxa collected during lake‐wide surveys in Lake Ontario, a Laurentian Great Lake, from 1964 to 2018. This information resulted from surveys funded by the governments of the United States and Canada to investigate the status and changes of Lake Ontario benthic community. Of the 13 lake‐wide benthic surveys conducted in Lake Ontario over the course of 54 yr, we were able to acquire taxonomic data to the species level for 11 of the surveys and data to the group level for the other two surveys. Density data are provided for taxa representing the Annelida, Arthropoda, Mollusca, Cnidaria, Nemertea, and Platyhelminthes phyla. Univariate and multivariate analyses revealed that the compositional structure of Lake Ontario invertebrate assemblages differed markedly by depth and were also significantly altered by the Dreissena spp. invasion in early 1990s. The introduction of invasive dreissenids has changed the community historically dominated by Diporeia, Oligochaeta, and Sphaeriidae, to a community dominated by quagga mussels and Oligochaeta. Considering the rarity of long‐term benthic data of high taxonomic resolution in lake ecosystems, this data set could be useful to explore broader aspects of ecological theory, including effects of different environmental factors and invasive species on community organization, functional and phylogenetic diversity, and spatial scale of variation in community structure. The data set could also be useful for studies on individual species including abundance and distribution, species co‐occurrence, and how the patterns of dominance and rarity change over space and time. Use of this data set for academic or educational purposes is encouraged as long as the data source is properly cited using the title of this Data Paper, the names of the authors, the year of publication, the journal name, and the article number. [ABSTRACT FROM AUTHOR]

The article discusses the study on the long-term changes in the Saline Lake Qarun in Egypt caused by anthropogenic activities and climate change. The study involves a survey of zooplankton and physico-chemical parameters on lake. Result shows that salinity in the lake was increased caused by climatic changes and global warming.

Eutrophication is a well‐known problem of global proportions with some easily recognizable and potentially harmful effects on aquatic habitats, but our knowledge on the underlying associated changes in ecosystem functioning is rather limited. Relevant studies suggest that seasonal variability in the functional composition of phytoplankton shows an increase as eutrophication progresses. The aim of the present study was to test this hypothesis through the assessment of long‐term changes in the functional diversity and composition of phytoplankton in a large shallow lake situated in Central Europe with a history of dramatic changes in trophic state. Contrary to our expectations, results have shown that the maximum range of compositional variability had a significant negative correlation with the summer biomass maxima. On the other hand, average seasonal variability measured as annual beta diversity exhibited an increasing trend throughout the years from the period of early eutrophication to the recent period of reoligotrophication, seemingly following a decline in functional richness and a long‐term rise in annual mean water temperature. The enhanced variability in phytoplankton succession implies that all the ecosystem processes connected to the phytoplankton follow more complex seasonal dynamics. Besides changing community structure, trophic state also seems to be an important factor in setting the limits to compositional changes during the annual cycle, whereas long‐term warming is likely to enhance instability in the phytoplankton. The trajectories of these two factors and the changes in seasonal succession indicate a lake in transition, urging more in‐depth research efforts to understand the impact of climate change on this specific ecosystem, and raise the question of whether the observed changes can also occur in other similar aquatic systems. [ABSTRACT FROM AUTHOR]