Recent Ecological Changes Research Articles

Intermediate host patterns of acanthocephalans in the Weser river system: co-invasion versus host-capture.

Anthropogenic interference is a major driver of ecological change in freshwater ecosystems. Pollution and the introduction of new species not only alter macrozoobenthic community structures, but can also affect their respective parasite communities. The ecology of the Weser river system experienced a drastic decline in biodiversity over the past century due to salinization caused by the local potash industry. As a response, the amphipod Gammarus tigrinus was released into the Werra in 1957. A few decades after the introduction and subsequent spread of this North American species, its natural acanthocephalan Paratenuisentis ambiguus was recorded in the Weser in 1988, where it had captured the European eel Anguilla anguilla as a novel host. To assess the recent ecological changes in the acanthocephalan parasite community, we investigated gammarids and eel in the Weser river system. In addition to P. ambiguus, 3 Pomphorhynchus species and Polymorphus cf. minutus were discovered. The introduced G. tigrinus serves as a novel intermediate host for the acanthocephalans Pomphorhynchus tereticollis and P. cf. minutus in the tributary Werra. Pomphorhynchus laevis is persistent in the tributary Fulda in its indigenous host Gammarus pulex. Pomphorhynchus bosniacus colonized the Weser with its Ponto-Caspian intermediate host Dikerogammarus villosus. This study highlights the anthropogenically driven changes in ecology and evolution in the Weser river system. Based on morphological and phylogenetic identification, the shifts in distribution and host usage described here for the first time contribute to the puzzling taxonomy of the genus Pomphorhynchus in times of ecological globalization.

Long-term hydrographic changes in the Gulf of California and ecological impacts: A crack in the World’s Aquarium?

Although the Gulf of California is widely recognized as a region of high productivity and biodiversity, recent oceanographic and ecological changes have had a significant impact on its overall health. We review the relevant history of the economically important fishery based on large Humboldt (jumbo flying) squid (Dosidicus gigas) (>50 cm mantle-length and 10 kg body weight) that existed in the Guaymas Basin from the 1990′s until 2009, when a strong El Niño was accompanied by precocious spawning of squid at extremely small size (<30 cm mantle length and 0.1 kg). This short-lived phenotype is characteristic of the equatorial part of the species range and cannot be profitably fished. This phenomenon also occurred in conjunction with the strong 1997–1998 El Niño. Although rapid recovery of squid size and landings occurred after the 1997–1998 event, recovery after 2009–2010 El Niño was still incomplete when another strong El Niño occurred in 2015–2016. This last event has led to fixation of the small size-at-maturity phenotype in the Gulf of California — an effective poleward migration of the tropical phenotype. We also document years between El Niño 2009–2010 and 2015–2016 as being characterized by significant subsurface warming, leading to decreased productivity and restricted nighttime foraging opportunities for squid in the upper water column. These climatic trends have likely altered trophic webs throughout the Gulf of California, impacting many other taxa, including small pelagic fishes that are ecologically vital and commercially harvested in large quantities, as well as a suite of larger teleost fishes that are targeted by sport fishers. From these disparate data sources, collected and collated in coordination with regional resource users and environmental monitoring programs, an overall pattern emerges of long-term decline across multiple taxa. We also present evidence of a significant abatement of subsurface warming after 2015 and consider when – or if – the Gulf of California will return to a ‘normal’ state like that prior to 2010. Despite the potential for shifting to a cooler oceanic regime, the small phenotype for jumbo squid has persisted until present (2022), and the overall trajectory of ecological recovery is unclear. Integrated analyses of additional oceanographic and biological time-series, fisheries records, and other data will be necessary to identify critical processes and trajectories occurring in the Gulf of California.

NDVI-based ecological dynamics of forest vegetation and its relationship to climate change in Romania during 1987–2018

Forests have become increasingly stressed by climate change, including in Romania over recent decades, but their response to climate dynamics has not yet been analysed in this country. This study aims to investigate, for the first time, recent ecological changes in forests across Romania, in relation to climate dynamics that affected the country from 1987 to 2018. To this end, countrywide remote sensing (Landsat) data were processed for forest boundaries over the 32 years, in order to compute annual (summer season data) Normalized Difference Vegetation Index (NDVI) datasets, which were subsequently investigated as trends using the Mann-Kendall test and Sen's slope estimator. Simultaneously, various climatic data (temperature, precipitation and reference evapotranspiration) were processed through interpolation techniques and via the same two statistical tools, and were subsequently used for exploring the impact of climate change on Romanian forestlands after 1987. The results highlighted general greening (increasing NDVI) trends of forests nationally (65% of all NDVI changes, which total over 30.000 km2 across Romania), which were dominated by widespread positive NDVI trends detected in the Carpathians region of Romania. This general ecological dynamic suggests a possible enhancement in vegetation productivity in the country’s high-altitude areas. Contrasting browning (decreasing NDVI) trends were found for 35% of Romanian forestlands marked by NDVI changes, especially apparent in the Extra-Carpathians (lowland) region, which indicates that in these cases forests were degraded or devitalized. However, the statistical significance of both greening and browning trends is limited across the country. The analysis of climatic trends and of correlations between annual NDVI and climate data indicated that recent warming throughout Carpathians may be an important driving force of forest greening in temperature-limited mountain regions. This finding is supported by an at least moderate intensity of air temperature – NDVI relationships (r correlation coefficient values of ∼50%, the highest of all eco-climatic relationships analysed), generally detected throughout mountain environments. At the same time, it seems that evapotranspiration increase accounted at least in part for forest browning in lowland areas, while the impact of precipitation in forest ecological dynamics remains unclear. All these findings can be useful for a better forest management under the future climate change conditions in Romania.

Recent divergent changes in Alaskan pinniped trophic position detected using compound-specific stable isotope analysis

Over the past century, Alaskan pinnipeds have experienced dramatic changes in abundance, but these changes have been highly variable across species and regions. In recent decades, changes in atmospheric forcing and sea surface temperature have been particularly pronounced in the Gulf of Alaska and eastern Bering Sea, impacting the food webs in which Alaskan pinnipeds forage. We used compound-specific stable isotope analysis of nitrogen in amino acids to estimate historic and modern trophic positions of harbor seals Phoca vitulina and Steller sea lions Eumetopias jubatus in the Gulf of Alaska and Bristol Bay. We applied a Bayesian hierarchical framework to determine whether shared trends through time exist across pinnipeds (classified by region and species) on decadal scales. Model results identified both shared trends through time and classification-specific decadal changes in pinniped trophic position. The largest change in trophic position occurred in the 2000s and 2010s and was observed in both Steller sea lions (median: 2.8) and harbor seals (median: 3.1) in the Gulf of Alaska, but not harbor seals in Bristol Bay or Iliamna Lake. Divergent trophic position patterns in the 2000s were identified in the western stock of Steller sea lions, which increased in trophic position, and sympatric harbor seals in the northern Gulf of Alaska, which decreased in trophic position. Our results indicate that these species have been experiencing unique food web conditions in recent decades in the Gulf of Alaska, likely in response to recent climate-induced ecological change in the region.

Forum: A Change in the Ecological Understanding of Rangelands in the Great Basin and Intermountain West and Implications for Management: Revisiting Mack and Thompson (1982)

Reevaluating assumptions about the ecology and management of sagebrush and salt desert shrub systems in the Great Basin and Intermountain West is a proper role for science. These are complex rangeland ecosystems, and our management applications need to account for this complexity. Understanding and reckoning this complexity is vital to the future existence of these rangeland systems and their ability to provide critical goods and ecosystem services to society. The most influential ecological claim of the past 40 yr is based on ideas presented by Mack and Thompson (1982), that Great Basin and Intermountain West plant communities evolved with few or perhaps no large hooved-grazing animals. Our thesis asserts that Mack and Thompson's position is based on 1) an oversimplification of complex, heterogeneous, and diverse ecosystems; 2) a poor understanding of science, both in 1982 and now; and 3) the attribution of all recent ecological changes to a single land use. We review the archaeological and historical record of vegetation and large grazing animals in the region and then revisit Mack and Thompson's (1982) interpretations of the rangeland plants and plant communities, forage quality and nutrition, and soil biotic crusts east and west of the Rocky Mountains, adding the information necessary for a more comprehensive interpretation. We finish by proposing an alternative paradigm to guide management and conservation of sagebrush and salt desert systems of the Great Basin and Intermountain West and beyond.

Climate change as the dominant driver of recent ecological changes in a semi-arid alpine lake from the Chinese Loess Plateau

Semi-arid areas of northern China are under increasing pressures from anthropogenic activities and climate change. Although wetland areas in these drylands have experienced dramatic, unidirectional shifts in their ecological status in recent centuries, fundamental driving forces are poorly quantified. Here, we examine changes in sedimentary proxies (diatoms, spectrally-inferred chlorophyll-a, stable isotopes) preserved in a radiometrically-dated core from Tianchi Lake, an alpine lake within the margin of the East Asian Summer Monsoon (EASM) limit in China’s southwestern Loess Plateau. Our algal trends were compared with regional instrumental records, changes in EASM intensity, and with previously published paleolimnological data from this same lake to determine the principal drivers of regional ecological changes. We found no clear evidence that geochemical and biological proxies were strongly affected by deforestation and other human activities. Major environmental changes during the past ~ 200 years were found to be predominantly driven by climatic fluctuations, extreme precipitation events, and changes in EASM intensity. Prior to ~ 1965 CE, diatom assemblages indicate an oligotrophic, clear water state. Shifts in dominance between benthic Staurosirella pinnata and planktonic Lindavia comensis were likely controlled by ice-cover dynamics. Between ~ 1965 and 1980 CE an abrupt shift to a turbid water state during a period of extreme precipitation events was caused by excessive nutrient-laden soil erosion in the already susceptible deforested catchment. This turbid period was evidenced by a rapid increase to dominance of Achnanthidium minutissimum, a sharp decline in oligotrophic Lindavia comensis, increased primary production, and peaks in sediment grain size and SiO2 content. Post- ~ 1980 CE, we provide evidence that a shift towards planktonic diatom dominance can best be explained by changes in climate and EASM intensity, despite substantial nitrogen deposition in the region during the past few decades. Specifically, a drier and warmer climate together with weakened EASM wind strength resulted in decreased erosion and a return to a clear water state, coupled with enhanced thermal stability. Collectively, these observations expand our understanding of how changes in climate, extreme precipitation events, and fluctuations in EASM intensity influence semi-arid alpine lakes in northern China, as well as climate’s leading role in driving ecological change over the past two centuries, despite the intensification of human disturbances during recent decades.

Recent climate-driven ecological changes in tropical montane lakes of Rwenzori Mountains National Park, central Africa

Rwenzori Mountains National Park, which straddles the border between the Democratic Republic of Congo and Uganda, has experienced rapid glacier loss since the beginning of the twentieth century, yet there has been little investigation of aquatic biodiversity change in the park. This study presents a paleolimnological analysis from Lake Mahoma (2990 m asl), which is situated in the bamboo-forest transition zone. Diatom and organic geochemistry data from a 39-cm-long sediment core with a basal age of c. 1715 CE were compared with new analyses of previously published data from Lakes Bujuku (3891 m asl) and Lower Kitandara (3989 m asl), in the alpine zone. Comparisons were made to determine if aquatic ecosystem changes exhibited similar inter-lake patterns over the past ~ 150 years of climate warming and glacial recession, or if only local change was apparent. The diatom flora of Lake Mahoma is acidophilous, dominated by Aulacoseira ikapoënsis since at least the mid eighteenth century. In recent decades, the obligate nitrogen-heterotroph Nitzschia palea increased in importance, concurrent with declining δ15Norg values. We suggest that these late twentieth century changes were linked to regional warming and increased thermal stratification of Lake Mahoma. Regional comparisons of the Rwenzori lakes were done using existing organic geochemistry records (total organic carbon, C/N and δ13Corg) and through diatom compositional turnover analyses, and categorisation of species into one of four diatom growth morphology traits, or guilds: tychoplanktonic, high-profile, low-profile and motile. Over the past 150 years, all three lakes showed unidirectional, compositional diatom turnover, indicating that deterministic processes had affected diatom communities. Declining turnover at each site is broadly mirrored by an increase in tychoplanktonic taxa, along with concomitant declines in high-profile diatoms at Lake Mahoma, and low-profile diatoms at Lake Bujuku, and at least for the past 60 years, at Lower Kitandara. The interplay between diatom guilds at all sites is mainly a consequence of competition for available resources. Sediment organic carbon at all sites comes from both autochthonous and allochthonous sources, the relative abundances of which are influenced by the time elapsed since lakes had glaciers in their catchment.

The Potential of Organic Sediments in Florida Spring Runs as Records of Environmental Change

The origin of modern spring flow in Florida is generally presumed to correspond with sea-level stabilization at or near present levels during the Middle Holocene. Low sea level and associated karstic aquifer drawdown have been assumed to have prevented artesian flow in current Florida spring systems throughout the Terminal Pleistocene. However, little paleoenvironmental work has been undertaken to test these assumptions. Substantial ecological changes within many of Florida’s spring runs over the past two decades have raised interest in the use of sediment core analyses to characterize the nature, extent, timing, and potential triggers of these changes. We evaluated the extent and age of organic material accumulation in a broad sample of fifteen spring runs in central Florida. Radiocarbon dating of sediment cores indicated that many of these runs have accumulated organic material for thousands of years; five of the fifteen spring runs contain organic material that pre-dates Holocene sea-level stabilization. Therefore, either saturation or inundation of Florida’s artesian spring runs was much more geographically and temporally variable than has been previously assumed. It is likely that paleoenviron-mental reconstructions of those runs with lengthy sediment records will produce new knowledge about paleoclimate, paleobiology, and more recent ecological change.

Recent climate-driven ecological change across a continent as perceived through local ecological knowledge.

Documenting effects of climate change is an important step towards designing mitigation and adaptation responses. Impacts of climate change on terrestrial biodiversity and ecosystems have been well-documented in the Northern Hemisphere, but long-term data to detect change in the Southern Hemisphere are limited, and some types of change are generally difficult to measure. Here we present a novel approach using local ecological knowledge to facilitate a continent-scale view of climate change impacts on terrestrial biodiversity and ecosystems that people have perceived in Australia. We sought local knowledge using a national web-based survey, targeting respondents with close links to the environment (e.g. farmers, ecologists), and using a custom-built mapping tool to ask respondents to describe and attribute recent changes they had observed within an area they knew well. Results drawn from 326 respondents showed that people are already perceiving simple and complex climate change impacts on hundreds of species and ecosystems across Australia, significantly extending the detail previously reported for the continent. While most perceived trends and attributions remain unsubstantiated, >35 reported anecdotes concurred with examples in the literature, and >20 were reported more than once. More generally, anecdotes were compatible with expectations from global climate change impact frameworks, including examples across the spectrum from organisms (e.g. increased mortality in >75 species), populations (e.g. changes in recruitment or abundance in >100 species, phenological change in >50 species), and species (e.g. >80 species newly arriving or disappearing), to communities and landscapes (e.g. >50 examples of altered ecological interactions). The overarching pattern indicated by the anecdotes suggests that people are more often noticing climate change losers (typically native species) than winners in their local areas, but with observations of potential ‘adaptation in action’ via compositional and phenological change and through arrivals and range shifts (particularly for native birds and exotic plants). A high proportion of climate change-related anecdotes also involved cumulative or interactive effects of land use. We conclude that targeted elicitation of local ecological knowledge about climate change impacts can provide a valuable complement to data-derived knowledge, substantially extending the volume of explicit examples and offering a foundation for further investigation.

Recent changes in the spring microplankton of Lake Baikal, Russia

Lake Baikal is facing several environmental stressors, including climate change and nearshore eutrophication. To assess recent ecological changes in Lake Baikal and provide a baseline for future comparisons, we sampled spring plankton communities from the pelagic zone of the lake in 2016 and compared these data with unpublished and published historical information going back to 1990. In 2016, one pelagic long-term monitoring station was sampled in early spring (March) during ice cover and 21 long-term monitoring stations located throughout the lake were sampled in late spring (May-June). We measured water chemistry parameters at most stations and the abundance, taxonomic composition and biomass of bacteria, ciliates and phytoplankton at several locations in different areas of the lake. Biotic parameters from 2016 were compared with historical data, showing significant changes in the spring pelagic microbial community since the 1990s. We show increased quantities of small species, mixotrophic ciliates, and the appearance (or increasing number) of small coloured and colourless flagellates. We also show substantially decreased densities of formerly dominant heavily silicified diatoms such as Aulacoseira spp. Since 2007, Synedra acus subsp. radians, a smaller and weakly silicified diatom, has dominated the spring plankton of the lake. These results suggest that Lake Baikal’s pelagic plankton community may be changing, with climate likely playing a dominant role in these changes.

Adaptation to Climate Change in an Interior Pacific Island Village: a Case Study of Nawairuku, Ra, Fiji

We examine how residents of Nawairuku, an interior village in Ra, Fiji, are experiencing and responding to recent social and ecological changes. An analysis of data collected using semi-structured interviews with 27 households reveals that household adaptability – the ability or capacity to adapt to the impacts of climatic variations – depends on access to livelihood assets. All households have access to social capital through familial networks, which lessens the burden of extreme weather events, namely cyclones and flooding. Households with access to tangible assets such as land and the equipment and resources to utilize it, together with intangible assets like motivation and knowledge are better positioned to adapt their agricultural practices to changing climatic conditions. Households headed by a capable individual were also better positioned to adapt. We conclude that remoteness promotes self-sufficiency and initiative, and access to livelihood assets influences household capacity to adapt.

Testing for human impacts in the mismatch of living and dead ostracode assemblages at nested spatial scales in subtropical lakes from the Bahamian archipelago

AbstractNaturally time-averaged accumulations of skeletal remains—death assemblages—provide reliable, albeit temporally coarse, information on the species composition and structure of communities in diverse settings, and their mismatch with local living communities usually signals recent human-driven ecological change. Here, we present the first test of live–dead mismatch as an indicator of human stress using ostracodes. On three islands along a gradient of human population density in the Bahamas, we compared the similarity of living and death assemblages in 10 lakes with relatively low levels of human stress to live–dead similarity in 11 physically comparable lakes subject to industrial, agricultural, or other human activities currently or in the past. We find that live–dead agreement in pristine lakes is consistently excellent, boding well for using death assemblages in modern-day and paleolimnological biodiversity assessments. In most comparison of physically similar paired lakes, sample-level live–dead mismatch in both taxonomic composition and species’ rank abundance is on average significantly greater in the stressed lakes; live–dead agreement is not lower in all samples from stressed lakes, but is more variable. When samples are pooled for lake-level and island-level comparisons, stressed lakes still yield lower live–dead agreement, but the significance of the difference with pristine lakes decreases—species that occur dead-only (or alive-only) in one sample are likely to occur alive (or dead) in other samples. Interisland differences in live–dead agreement are congruent with, but not significantly correlated with, differences in human population density. This situation arises from heterogeneity in the timing and magnitudes of stresses and in the extent of poststress recovery. Live–dead mismatch in ostracode assemblages thus may be a reliable indicator of human impact at the sample level with the potential to be a widely applicable tool for identifying impacted habitats and, perhaps, monitoring the progress of their recovery.

Ecosystem Responses to Climate-Related Changes in a Mediterranean Alpine Environment Over the Last ~ 180 Years

The effect of recent climatic warming is significant in the Mediterranean region, especially in high-mountain areas. This study uses multiple sedimentary proxies from Rio Seco Lake, a remote alpine lake in the Sierra Nevada, southeastern Spain, to reconstruct recent environmental and ecological changes in the lake and catchment. Two main climatic periods can be distinguished during the past 180 years: Period One (1820 to ~ 1920s) characterized by colder and wetter conditions than the more recent Period Two (~ 1920s to the present), characterized by warmer and drier conditions. Independent proxies such as subfossil chironomid assemblages, n-alkane indices, pollen data and/or spectrally inferred chlorophyll-a concentrations indicate a longer ice-cover period, colder water temperature and more pronounced accumulation of snow in the catchment during Period One than in Period Two, likely producing water stress for catchment plant growth because of the low rate of ice melting in Period One. As temperature increases and precipitation decreases from the 1920s onwards, a wider development of wetland plants is observed, which is associated with the longer warm season that contributed to snow and ice melting in the catchment. This continuing temperature rise and precipitation decrease over the past 60-years by ~ 0.24°C per decade and –0.92 mm/y, respectively, lead to an important increase in chlorophyll-a and changes in lake biotic assemblages. Major chironomid community structure changes to warmer water taxa were recorded, resulting in a 2°C increase in mean July air temperature inferred by chironomids from ~ 1950 onwards. An inferred increase in primary production for the past few decades is consistent with higher temperatures, while wider development of wetland plants is associated with longer warm season. The coherence between independent environmental proxies, each associated with distinct mechanistic linkages to climatic shifts, strengthens our interpretations of a recent warming trend and an intensification of summer drought in this high-mountain area leading to distinct changes in the lake and its catchment. The impact of this climate change on the summits of Sierra Nevada and its influence transcends its geographical limits because these systems provide ecosystem services to a vast area.

Recent ecological change in ancient lakes

AbstractAncient lakes are among the best archivists of past environmental change, having experienced more than one full glacial cycle, a wide range of climatic conditions, tectonic events, and long association with human settlements. These lakes not only record long histories of environmental variation and human activity in their sediments, but also harbor very high levels of biodiversity and endemism. Yet, ancient lakes are faced with a familiar suite of anthropogenic threats, which may degrade the unusual properties that make them especially valuable to science and society. In all ancient lakes for which data exist, significant warming of surface waters has occurred, with a broad range of consequences. Eutrophication threatens both native species assemblages and regional economies reliant on clean surface water, fisheries, and tourism. Where sewage contributes nutrients and heavy metals, one can anticipate the occurrence of less understood emerging contaminants, such as pharmaceuticals, personal care products, and microplastics that negatively affect lake biota and water quality. Human populations continue to increase in most of the ancient lakes’ watersheds, which will exacerbate these concerns. Further, human alterations of hydrology, including those produced through climate change, have altered lake levels. Co‐occurring with these impacts have been intentional and unintentional species introductions, altering biodiversity. Given that the distinctive character of each ancient lake is strongly linked to age, there may be few options to remediate losses of species or other ecosystem damage associated with modern ecological change, heightening the imperative for understanding these systems.

Climatic factors as risks of recent ecological changes in the shallow zone of Lake Baikal

Eutrophication processes have been recorded in many world’s freshwater reservoirs, which are sources of drinking water. More and more investigations show that global warming is the main natural factor that causes eutrophication. In recent years, signs of eutrophication have also been recorded in Lake Baikal containing 20% of the world’s freshwater reserves. Therefore, we performed the first comprehensive analysis of long-term changes in climatic parameters capable to provoke negative changes in the shallow zone. The largest number of anomalies of climatic indices has been recorded in the 21st century. Moreover, the current decade has been the most favorable for the emergence of negative processes in the lake (outbreak of the mass growth of algae and aquatic vegetation, rotting of their remains at the bottom and on the shores of the lake, changes in the structure and zoning of biocoenoses, etc.). The main natural conditions favoring the emergence of negative signs are elevated temperatures of the air and lake shore water, reduced amount of precipitation, reduced inflow of river waters into Baikal and lowering of its water level, low-water season, and weakening of wind currents, water exchange processes, and, as a result, water self-purification. In the period of continuing global warming, it is necessary to study the climate effect on the processes in the shallow zone and to carry out long-term monitoring for elucidation of recent and expected changes in the ecological state of Lake Baikal and for their valid interpretation.

Adaptation to climate change and freshwater resources in Vusama village, Viti Levu, Fiji

Changing precipitation patterns including more intense and prolonged dry periods have become a growing concern for people living in the Pacific Island region. People in the region are particularly sensitive to these changes given their resource-based livelihoods and high dependence on rainfall for their freshwater needs. Despite this, little attention has been given to understanding the implications of climatic changes for people and their capacity to manage these changes. This paper assesses human vulnerability to climate change (as it relates to fresh water resources) in Vusama, an iTaukei village in southwest Viti Levu, Fiji in the context of recent social and ecological changes. An analysis of data collected using a vulnerability approach that included semi-structured interviews, participant observation and analysis of secondary sources reveal that climate change together with behavioural changes are negatively affecting availability and access to clean freshwater, with implications for household economies, food security and human health. In particular, prolonged drought and changing seasonal patterns, together with people’s increasing reliance on a village borehole in lieu of family wells have resulted in a freshwater crisis. People are coping by using earnings from wage employment and harvesting and selling seafood to buy water and vegetables, rationing freshwater and depending on extended social networks for fresh produce. Current responses are reactive and short-term. Longer-term adaptation strategies are needed that consider expected future climate change and broader human development goals.

Chironomid fauna of the lakes from the Pechora river basin (east of European part of Russian Arctic): Ecology and reconstruction of recent ecological changes in the region

We investigated chironomid fauna of surface sediments and a short sediment core (Bol’shoy Kharbey Lake) from Pechora river basin, Northern Russia. Twenty three investigated lakes have thermokarst, glacial or floodplain origin and are characterised by low mineralization, mostly hydrocarbon-calcium type of water and low concentration of nutrients. Most of the lakes have circumneutral pH around ≤7 and only two lakes are slightly more acidic with pH ≤ 6. Ninety six chironomid taxa were identified in the surface sediments. Distribution of chironomids in the studied region is driven by continentality, mean TJuly and рН. Chironomid communities from the core of the B. Kharbei Lake demonstrate the highest similarity with the fauna of the deeper lakes of the glacial origin. The glacial lakes have the highest indices of continentality and the lowest winter temperatures within the investigated data set. The chironomid fauna of the glacial lakes is composed of the profundal, oligotrophic and cold-stenotherm taxa. The fauna of the floodplain and thermokarst lakes is more closely related to TJuly and is composed of littoral and phytophilic taxa of meso–or eutrophic waters and moderate temperature conditions. The fauna of the acidic thermokarst lakes considerably differs from the other lakes. Chironomid communities here are represented by tolerant to acidification taxa, and by the typically littoral and shallow water acid-tolerant taxa that apparently also can tolerate acidification. Studied sediment record covers ca last 200 years. The reconstructed TJuly during the entire period remain slightly below the modern temperatures. From 1970 reconstructed TJuly shows steady increase to the modern level. The reconstructed water depths (WDs) of the lake are higher than today till 1980. The highest WDs are reconstructed for ca 1970. After that the WDs gradually decrease to the modern level. Changes of the WDs are most probably related to changes in the precipitation rate.

Phenotypic plasticity in morphological features of Thelaxes suberi (Del Guercio, 1911) (Hemiptera: Aphidoidea) feed on Quercus (L.) species

Phenotypic plasticity is a common and important phenomenon in aphids, particularly in host plant utilization. It has been shown that Thelaxes suberi species fed on three closely related Quercus species showed high amount of phenotypic plasticity in morphological characters. Thelaxes suberi population has the largest morphological features on Quercus infectoria and the smallest morphological features on the Quercus coccifera. It was thought that these differences related with the total protein content and level of amino acid in acorns of the host plant where Thelaxes individuals were collected during this study. Findings of the study indicated how high is phenotypic plasticity capacity of aphid species and interactions with host plant properties. Another important implication of the result is that as aphid has a close relationship with host plant and even small amount of changes in the same Quercus species caused that amount of plasticity in Thelaxes species. Recent ecological changes including climatic fluctuations directly influences host plants morphological/nutritional composition and might also impacts the diversity and distribution of aphid species. Findings were also discussed for possible changes in host plant range of the T. suberi as a result of the current phenotypic plasticity and possible interactions between different types of phenotypic plasticities.

Epidemiology and Characteristics of Rickettsia australis (Queensland Tick Typhus) Infection in Hospitalized Patients in North Brisbane, Australia.

Queensland tick typhus (QTT; Rickettsia australis) is a spotted fever group (SFG) rickettsial infection endemic to Australia. It is an underreported and often unrecognized illness with poorly-defined epidemiology. This article describes epidemiological features and the geographical distribution of QTT in hospitalized patients. Cases of QTT were identified retrospectively from 2000–2015 at five sites in Northern Brisbane through a pathology database. Included cases had a four-fold rise in SFG-specific serology, a single SFG-specific serology ≥256 or an SFG-specific serology ≥128 with a clinically consistent illness. Of the fifty cases identified by serology, 36 were included. Age ranged from 3–72 years (with a mean of 39.5 years) with a male-to-female ratio of 1:1.1. Fifteen of 36 (42%) study participants had hobbies and/or occupations linked with the acquisition of the disease. Seventeen of 36 (47%) identified a tick bite in the days preceding presentation to hospital, and reported exposure to a known animal host was minimal (25%). QTT infection occurred throughout the year, with half of the cases reported between April and July. Recent ecological and sociocultural changes have redefined the epidemiology of this zoonotic illness, with areas of higher infection risk identified. Heightened public health awareness is required to monitor QTT disease activity.

Chironomid Fauna of the Lakes from the Pechora River Basin (Bolshezemelskaia Tundra, Northern Russia): Ecology and Reconstruction of Recent Ecological Changes in the Region

Chironomid Fauna of the Lakes from the Pechora River Basin (Bolshezemelskaia Tundra, Northern Russia): Ecology and Reconstruction of Recent Ecological Changes in the Region