Predicted Climate Change Conditions Research Articles

Polygenic adaptation of a cosmopolitan pest to a novel thermal environment.

The fluctuation in temperature poses a significant challenge for poikilothermic organisms, notably insects, particularly in the context of changing climatic conditions. In insects, temperature adaptation has been driven by polygenes. In addition to genes that directly affect traits (core genes), other genes (peripheral genes) may also play a role in insect temperature adaptation. This study focuses on two peripheral genes, the GRIP and coiled-coil domain containing 2 (GCC2) and karyopherin subunit beta 1 (KPNB1). These genes are differentially expressed at different temperatures in the cosmopolitan pest, Plutella xylostella. GCC2 and KPNB1 in P. xylostella were cloned, and their relative expression patterns were identified. Reduced capacity for thermal adaptation (development, reproduction and response to temperature extremes) in the GCC2-deficient and KPNB1-deficient P. xylostella strains, which were constructed by CRISPR/Cas9 technique. Deletion of the PxGCC2 or PxKPNB1 genes in P. xylostella also had a differential effect on gene expression for many traits including stress resistance, resistance to pesticides, involved in immunity, trehalose metabolism, fatty acid metabolism and so forth. The ability of the moth to adapt to temperature via different pathways is likely to be key to its ability to remain an important pest species under predicted climate change conditions.

Long-term decline in body condition of female Australian fur seals: potential causes and implications

The Australian fur seal (Arctocephalus pusillus doriferus, AUFS) population is still recovering from the over-exploitation of the commercial-sealing era (18th and 19th centuries). While the population is considered to be only < 47% of its pre-harvest size, it now represents the greatest resident marine predator biomass in the south-eastern Australian marine ecosystem. The region is experiencing rapid environmental change and, as a keystone predator species, the AUFS is an indicator of ecosystem health. In the present study, the body mass, standard length and body condition index (BCI) were analysed between 1997-2021 in adult female AUFS provisioning pups on Kanowna Island (northern Bass Strait), the third largest colony for the species. While substantial inter-annual fluctuations were observed, there was no temporal trend in standard length during the 23-year study period. In contrast, body mass and, consequently, BCI decreased significantly, suggesting the population is experiencing changing nutritional conditions. While these changes do not appear to be due to competition with commercial fisheries or population expansion, weak but significant negative relationships were observed between BCI and 1-year lagged sea surface temperature and summer zonal winds in the Bonney Upwelling region, and both current- and 2-year lagged Indian Ocean Dipole (IOD). These findings suggest the BCI of AUFS may continue to decline under predicted climate change conditions. While a lack of a concurrent decline in pup production could indicate a degree of nutritional tolerance or flexibility in energy allocation, further monitoring is required to assess decreases in reproductive parameters (e.g., birth mass, pre-weaning growth rates) or vital rates, which would be expected with continued nutritional stress.

A very long-chain fatty acid enzyme gene, PxHacd2 affects the temperature adaptability of a cosmopolitan insect by altering epidermal permeability

Temperature fluctuations pose challenges to poikilotherms, such as insects, especially under climate change conditions. Very long-chain fatty acids (VLCFAs) form important structural components of membranes and epidermal surfaces, so play important roles in adaptation to temperature stress in plants. It has been unclear whether VLCFAs are involved in epidermis formation and thermal resistance in insects. In this study, we focused on the 3-hydroxy acyl-CoA dehydratase 2 (Hacd2), an important enzyme in the synthesis pathway of VLCFAs, in a cosmopolitan pest, the diamondback moth, Plutella xylostella. Hacd2 was cloned from P. xylostella and the relative expression pattern was identified. Epidermal permeability increased with the decreased VLCFAs in the Hacd2-deficient P. xylostella strain, which was constructed by using the CRISPR/Cas9 system. Survival and fecundity of the Hacd2-deficient strain was significantly lower than that of the wildtype strain when subject to desiccating environmental stress. Hacd2 mediates thermal adaptability in P. xylostella by changing epidermal permeability so is likely to be key to its remaining a major pest species under predicted climate change conditions.

Changing climate may mitigate the invasiveness risk of non-native salmonids in the Danube and Adriatic basins of the Balkan Peninsula (south-eastern Europe)

Salmonids are an extensively hatchery-reared group of fishes that have been introduced worldwide mainly for their high commercial and recreational value. The Balkan Peninsula (south-eastern Europe) is characterised by an outstanding salmonid diversity that has become threatened by the introduction of non-native salmonids whose potential risk of invasiveness in the region remains unknown and especially so under predicted climate change conditions. In this study, 13 extant and four horizon non-native salmonid species were screened for their risk of invasiveness in the Danube and Adriatic basins of four Balkan countries. Overall, six (35%) of the screened species were ranked as carrying a high risk of invasiveness under current climate conditions, whereas under predicted conditions of global warming, this number decreased to three (17%). Under current climate conditions, the very high risk (‘top invasive’) species were rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta (sensu stricto), whereas under predicted climate change, this was true only of O. mykiss. A high risk was also attributed to horizon vendace Coregonus albula and lake charr Salvelinus namaycush, and to extant Atlantic salmon Salmo salar and brook trout Salvelinus fontinalis, whose risk of invasiveness, except for S. fontinalis, decreased to medium. For the other eleven medium-risk species, the risk score decreased under predicted climate change, but still remained medium. The outcomes of this study reveal that global warming will influence salmonids and that only species with wider temperature tolerance, such as O. mykiss will likely prevail. It is anticipated that the present results may contribute to the implementation of appropriate management plans to prevent the introduction and translocation of non-native salmonids across the Balkan Peninsula. Additionally, adequate measures should be developed for aquaculture facilities to prevent escapees of non-native salmonids with a high risk of invasiveness, especially into recipient areas of high conservation value.

Environmental conditions lead to shifts in individual communication, which can cause cascading effects on soundscape composition.

Climate change is increasing aridity in grassland and desert habitats across the southwestern United States, reducing available resources and drastically changing the breeding habitat of many bird species. Increases in aridity reduce sound propagation distances, potentially impacting habitat soundscapes, and could lead to a breakdown of the avian soundscapes in the form of loss of vocal culture, reduced mating opportunities, and local population extinctions. We developed an agent‐based model to examine how changes in aridity will affect both sound propagation and the ability of territorial birds to audibly contact their neighbors. We simulated vocal signal attenuation under a variety of environmental scenarios for the south, central semi‐arid prairies of the United States, ranging from contemporary weather conditions to predicted droughts under climate change. We also simulated how changes in physiological conditions, mainly evaporative water loss (EWL), would affect singing behavior. Under contemporary and climate change‐induced drought conditions, we found that significantly fewer individuals successfully contacted all adjacent neighbors than did individuals in either the contemporary or predicted climate change conditions. We also found that at higher sound frequencies and higher EWL, fewer individuals were able to successfully contact all their neighbors, particularly in drought and climate change drought conditions. These results indicate that climate change‐mediated aridification may alter the avian soundscape, such that vocal communication no longer effectively functions for mate attraction or territorial defense. As climate change progresses, increased aridity in current grasslands may favor shifts toward low‐frequency songs, colonial resource use, and altered songbird community compositions.

Negative relationship between thermal tolerance and plasticity in tolerance emerges during experimental evolution in a widespread marine invertebrate.

Whether populations can adapt to predicted climate change conditions, and how rapidly, are critical questions for the management of natural systems. Experimental evolution has become an important tool to answer these questions. In order to provide useful, realistic insights into the adaptive response of populations to climate change, there needs to be careful consideration of how genetic differentiation and phenotypic plasticity interact to generate observed phenotypic changes. We exposed three populations of the widespread copepod Acartia tonsa (Crustacea) to chronic, sublethal temperature selection for 15 generations. We generated thermal survivorship curves at regular intervals both during and after this period of selection to track the evolution of thermal tolerance. Using reciprocal transplants between ambient and warming conditions, we also tracked changes in the strength of phenotypic plasticity in thermal tolerance. We observed significant increases in thermal tolerance in the Warming lineages, while plasticity in thermal tolerance was strongly reduced. We suggest these changes are driven by a negative relationship between thermal tolerance and plasticity in thermal tolerance. Our results indicate that adaptation to warming through an increase in thermal tolerance might not reduce vulnerability to climate change if the increase comes at the expense of tolerance plasticity. These results illustrate the importance of considering changes in both a trait of interest and the trait plasticity during experimental evolution.

Identifying threats from introduced and translocated non-native freshwater fishes in Croatia and Slovenia under current and future climatic conditions

Introduced and translocated non-native species are a major threat to biodiversity, especially in aquatic habitats. Efforts aimed at the mitigation of impacts and the implementation of preventative measures for the conservation of native biota must rely upon an accurate evaluation of the risks posed by non-native invasive species and are expected to be strengthened by international collaboration. In this study, 76 non-native freshwater fish species of which 48 extant (both introduced and translocated) and 28 horizon were screened for their risk of invasiveness in the neighbouring countries of Croatia and Slovenia under current and future climatic conditions. Using the Aquatic Species Invasiveness Screening Kit (AS-ISK), threshold scores for the Basic Risk Assessment (BRA) and for the combined BRA and Climate Change Assessment (BRA + CCA) allowed to distinguish with a high level of accuracy between low-, medium- and high-risk species – the latter representing ≈70% of the screened species. Brown bullhead Ameiurus nebulosus, round goby Neogobius melanostomus, topmouth gudgeon Pseudorasbora parva and Wels catfish Silurus glanis were the highest-scoring species for Croatia, and Ameiurus nebulosus, snakehead Channa argus and Pseudorasbora parva for Slovenia. There were discrepancies in medium- and high-risk rankings between Croatia and Slovenia for 12 species. Upon comparison of the BRA outcomes with those based on the Freshwater Fish Invasiveness Screening Kit (the predecessor of the AS-ISK), the risk changed for six species in Croatia and five in Slovenia. After accounting for predicted climate change conditions, the BRA + CCA risk scores increased for ≈50% of the species, with western mosquitofish Gambusia affinis, channel catfish Ictalurus punctatus and black carp Mylopharyngodon piceus achieving the highest score increment for Croatia, and round goby Neogobius melanostomus and Chinese (Amur) sleeper Perccottus glenii for Slovenia. The present outcomes will assist decision-makers in the implementation of appropriate measures for the management of extant non-native species and the potential introduction of horizon species. This is important for the regulation of pet trade and aquaculture as well as for management strategies aimed at the conservation of native biodiversity, which in the case of neighbouring countries/jurisdictions will benefit from joint efforts relying on a full risk assessment for the species classified at higher risk of invasiveness.

Experimental evidence of uncertain future of the keystone ragworm Hediste diversicolor (O.F. Müller, 1776) under climate change conditions

It is currently assumed that climate change related factors pose severe challenges to biodiversity maintenance. This paper assesses the multi-stressor effects of elevated temperature (15 °C as control, 25 °C as elevated) and CO2 levels (pH 8.1 as control, 7.5 and 7.0 representing acidifying conditions) on the physiological (survival and regenerative capacity), behavioral (feeding and burrowing activities), and biochemical changes (metabolic capacity, oxidative status and biotransformation mechanisms) experienced by the keystone polychaete Hediste diversicolor. Temperature rise enlarged the adverse effect of marine acidification on the survival of H. diversicolor, delayed the beginning of the excavation activity, enhancing the negative effects that pH decrease had in the burrowing behavior of this polychaete. Additionally, regardless of the temperature, exposure of H. diversicolor to acidification results in a reduction in the feeding rate. It is the first time that this decreased feeding capacity is found related to seawater acidification in this species. The healing of the wound and the blastemal formation were retarded due to these two climatic factors which hinder the regenerative process of polychaetes. These vital physiological functions of H. diversicolor can be related to the oxidative stress induced by climate change conditions since free radicals overproduced will impair cells functioning, affecting species biochemical and physiological performance, including feeding and tissue regeneration. The present results also demonstrated that although polychaetes' metabolic capacity was enhanced under stress conditions, organisms were still able to increase or maintain their energy reserves. Our findings are of major environmental relevance considering that predicted climate change conditions will affect species vital and ecological and physiological capacities. These can be translated into shrinking not only at the individual and population level but also in microbial and endofaunal diversities, in the detritus processing in estuaries and biogeochemical cycles at the ecosystem level. Thus the conservation of H. diversicolor populations is vital for the normal functioning of estuarine mudflat ecosystems.

Evaluating the impact of the weather conditions on the influenza propagation

BackgroundPredicting the details of how an epidemic evolves is highly valuable as health institutions need to better plan towards limiting the infection propagation effects and optimizing their prediction and response capabilities. Simulation is a cost- and time-effective way of predicting the evolution of the infection as the joint influence of many different factors: interaction patterns, personal characteristics, travel patterns, meteorological conditions, previous vaccination, etc. The work presented in this paper extends EpiGraph, our influenza epidemic simulator, by introducing a meteorological model as a modular component that interacts with the rest of EpiGraph’s modules to refine our previous simulation results. Our goal is to estimate the effects of changes in temperature and relative humidity on the patterns of epidemic influenza based on data provided by the Spanish Influenza Sentinel Surveillance System (SISSS) and the Spanish Meteorological Agency (AEMET).MethodsOur meteorological model is based on the regression model developed by AB and JS, and it is tuned with influenza surveillance data obtained from SISSS. After pre-processing this data to clean it and reconstruct missing samples, we obtain new values for the reproduction number of each urban region in Spain, every 10 minutes during 2011. We simulate the propagation of the influenza by setting the date of the epidemic onset and the initial influenza-illness rates for each urban region.ResultsWe show that the simulation results have the same propagation shape as the weekly influenza rates as recorded by SISSS. We perform experiments for a realistic scenario based on actual meteorological data from 2010-2011, and for synthetic values assumed under simplified predicted climate change conditions. Results show that a diminishing relative humidity of 10% produces an increment of about 1.6% in the final infection rate. The effect of temperature changes on the infection spread is also noticeable, with a decrease of 1.1% per extra degree.Conclusions: Using a tool like ours could help predict the shape of developing epidemics and its peaks, and would permit to quickly run scenarios to determine the evolution of the epidemic under different conditions. We make EpiGraph source code and epidemic data publicly available.

Mediterranean Long Shelf-Life Landraces: An Untapped Genetic Resource for Tomato Improvement.

The Mediterranean long shelf-life (LSL) tomatoes are a group of landraces with a fruit remaining sound up to 6–12 months after harvest. Most have been selected under semi-arid Mediterranean summer conditions with poor irrigation or rain-fed and thus, are drought tolerant. Besides the convergence in the latter traits, local selection criteria have been very variable, leading to a wide variation in fruit morphology and quality traits. The different soil characteristics and agricultural management techniques across the Mediterranean denote also a wide range of plant adaptive traits to different conditions. Despite the notorious traits for fruit quality and environment adaptation, the LSL landraces have been poorly exploited in tomato breeding programs, which rely basically on wild tomato species. In this review, we describe most of the information currently available for Mediterranean LSL landraces in order to highlight the importance of this genetic resource. We focus on the origin and diversity, the main selective traits, and the determinants of the extended fruit shelf-life and the drought tolerance. Altogether, the Mediterranean LSL landraces are a very valuable heritage to be revalued, since constitutes an alternative source to improve fruit quality and shelf-life in tomato, and to breed for more resilient cultivars under the predicted climate change conditions.

Simulated climate change decreases nutrient resorption from senescing leaves.

Nutrient resorption is the process whereby plants recover nutrients from senescing leaves and reallocate them to storage structures or newer tissues. Elemental resorption of foliar N and P has been shown to respond to temperature and precipitation, but we know remarkably little about the influence of warming and drought on the resorption of these and other essential plant macro- and micronutrients, which could alter the ability of species to recycle their nutrients. We conducted a 5year manipulative field study to simulate predicted climate change conditions and studied the effects of warming (W), rainfall reduction (RR), and their combination (W+RR) on nutrient resorption efficiency in five coexisting shrub species in a semiarid shrubland. Both mature and senesced leaves showed significant reductions in their nutrient contents and an altered stoichiometry in response to climate change conditions. Warming (W, W+RR) reduced mature leaf N, K, Ca, S, Fe, and Zn and senesced leaf N, Ca, Mg, S, Fe, and Zn contents relative to ambient temperature conditions. Warming increased mature leaf C/N ratios and decreased N/P and C/P ratios and increased senesced leaf C/N and C/P ratios. Furthermore, W and W+RR reduced nutrient resorption efficiencies for N (6.3%), K (19.8%), S (70.9%) and increased Ca and Fe accumulation in senesced leaves (440% and 35.7%, respectively) relative to the control treatment. Rainfall reduction decreased the resorption efficiencies of N (6.7%), S (51%), and Zn (46%). Reductions in nutrient resorption efficiencies with warming and/or rainfall reduction were rather uniform and consistent across species. The negative impacts of warming and rainfall reduction on foliar nutrient resorption efficiency will likely cause an impairment of plant nutrient budgets and fitness across coexisting native shrubs in this nutrient-poor habitat, with probable implications for key ecosystem functions such as reductions in nutrient retention in vegetation, litter decomposition, and nutrient cycling rates.

Risk screening of the potential invasiveness of non-native jellyfishes in the Mediterranean Sea

The aim of the present study was to risk screen 45 jellyfish species (30 hydromedusae, 14 scyphomedusae, one cubomedusa) for their potential invasiveness in the Mediterranean Sea to aid managers in making informed decisions on targeting appropriate species for management. Using the Aquatic Species Invasiveness Screening Kit (AS-ISK), calibrated basic and climate-change threshold assessment scores of 6.5 and 12.5, respectively, were identified for distinguishing reliably between species that pose ‘low-to-medium’ and ‘high’ risk of becoming invasive in the risk assessment area. Using these thresholds, 16 species were classified as high risk, 23 as medium risk and six as low risk under current climate conditions. Whereas, under future climate conditions, 13, 30 and two species, respectively, were classified as high, medium and low risk, respectively. Upside-down jellyfish Cassiopea andromeda, Australian spotted jellyfish Phyllorhiza punctata, sea nettle Chrysaora quinquecirrha and Rhopilema nomadica were the highest-scoring species, with the maximum increase in risk score under predicted climate change conditions being achieved by C. andromeda.

The influence of climate change related factors on the response of two clam species to diclofenac.

Diclofenac (DIC) is one of the non-steroidal anti-inflammatory drugs (NSAID) with higher consumption rates, used in both human and veterinary medicine. Previous studies already demonstrated the presence of this drug in aquatic environments and adverse effects towards inhabiting organisms. However, with the predictions of ocean acidification and warming, the impacts induced by DIC may differ from what is presently known and can be species-dependent. Thus, the present study aimed to comparatively assess the effects caused by DIC in the clams Ruditapes philippinarum and Ruditapes decussatus and evaluate if these impacts were influenced by pH and temperature. For this, organisms were acclimated for 30 days at two different temperature and pH (control conditions: pH 8.1, 17 °C; climate change forecasted scenario: pH 7.7, 20 °C) in the absence of drugs (experimental period I) followed by 7 days exposure under the same water physical parameters but in absence or presence of the pharmaceutical drug (at 1 μg/L, experimental period II). Biochemical responses covering metabolic capacity, oxidative stress and damage-related biomarkers were contrasted in clams at the end of the second experimental period. The results showed that under actual conditions, R. philippinarum individuals exposed to DIC presented enhanced antioxidant activities and reduced their respiration rate compared with non-contaminated clams. When exposed to the predicted climate change conditions, a similar response was observed in contaminated clams, but in this case clams increased their metabolic activities probably to fight the stress caused by the combination of both stressors. When R. decussatus was exposed to DIC, even at actual pH and temperature conditions, their antioxidant defences were also elevated but their baseline enzymatic activities were also naturally higher in respect to R. philippinarum. Although clams may use different strategies to prevent DIC damage, both clam species showed under low pH and high temperature limited oxidative stress impacts in line with a lower DIC bioaccumulation. The present findings reveal that predicted climate change related factors may not enhance the impacts of DIC in Ruditapes clams in a species-dependent manner although both displayed particular mechanisms to face stress.

Climate Change Impacts on Groundwater Resources in the Coastal Karstic Adriatic Area: A Case Study from the Dinaric Karst

The Bokanjac–Policnik system, as a complex set of mutually interrelated Dinaric karst catchments and sub-catchments, is a highly vulnerable and limited groundwater source for the wider Zadar area in northern Dalmatia, Croatia. Based on hydrogeological, hydrochemical, and hydrological research, including the prediction of groundwater discharge by the end of the twenty-first century, a complex study was performed with the following main aims: (1) groundwater protection in the present state, (2) assessment of future groundwater protection, and (3) prediction of drinking water availability and quality under the predicted climate change conditions. Long-term prediction of changes in groundwater quantity, as well as investigations of trends in groundwater quality, will allow us to protect this essential natural resource with respect to possible negative trends. The results showed that a significant decrease in the quantity of available groundwater is possible and that extraction will have to be well planned because any decrease in the groundwater pressure in this area will cause a further decrease in quality, especially regarding the possibility of seawater intrusions into the aquifer. The results of this study were incorporated in sanitary protection zones.

Tomato landraces as a source to minimize yield losses and improve fruit quality under water deficit conditions

The predicted climate change conditions are forcing crop improvement researchers to find drought tolerant genotypes. The aim of this experiment was to screen a large tomato (Solanum lycopersicum L.) collection cultivated under well-watered and water deficit conditions, in order to identify those genotypes with the best performance under water shortage. Thus, 165 tomato genotypes including different cultivars (landraces and modern genotypes) and fruit types (processing, big size, long shelf-life and cherry) were grown in open field under two different cultivation regimes: well-watered (WW, covering 100% crop evapotranspiration demands) and water deficit (WD, irrigation stopped one month after field transplantation). Several leaf-level traits, yield and fruit quality were measured. Large variability was found under WW, with 20-fold variations in yield among genotypes. No differences in yield or fruit quality traits were found between modern genotypes and landraces, while differences in these parameters were observed based on the fruit type. Water deficit affected the observed variability, with a general decrease of yield and increases of fruit quality. Cluster analysis based on fruit traits placed several landraces in the same cluster that the most productive modern genotypes, irrespective of the water treatment. Variable responses to WD were observed, depending on the fruit or cultivar type. Carbon isotope composition was positively correlated with leaf nitrogen content, and determined the yield limit under both treatments. The results of this study highlight the potential of landraces for minimizing yield reduction under WD and increasing fruit quality, having similar or even better performance as compared to modern improved genotypes.

Production of corn in Serbia in the light of climate change

This paper presents the basic elements of maize production technology in Serbia. For their good knowledge, it is necessary to be familiar with the basic biological requirements of the species, phenology and its particular requirements for water, heat, soil conditions and mineral nutrition. A special emphasis in this paper is given to recent research by the author regarding the correction of production technology (selection of hybrids, time and density of sowing, etc.) from the aspect of knowing the weather conditions of the year to the moment of sowing and the amount and position of available nitrogen in the soil profile during the spring before sowing. In the light of predicted climate change conditions for the Republic of Serbia, the authors of this paper have proposed and appropriated adaptation measures. The general conclusion is that there are no general recipes for the correct production technology of this plant species, but should be adapted to each specific year, field and hybrid.

Tolerance and potential for adaptation of a Baltic Sea rockweed under predicted climate change conditions

Climate change is threating species' persistence worldwide. To predict species responses to climate change we need information not just on their environmental tolerance but also on its adaptive potential. We tested how the foundation species of rocky littoral habitats, Fucus vesiculosus, responds to combined hyposalinity and warming projected to the Baltic Sea by 2070–2099. We quantified responses of replicated populations originating from the entrance, central, and marginal Baltic regions. Using replicated individuals, we tested for the presence of within-population tolerance variation. Future conditions hampered growth and survival of the central and marginal populations whereas the entrance populations fared well. Further, both the among- and within-population variation in responses to climate change indicated existence of genetic variation in tolerance. Such standing genetic variation provides the raw material necessary for adaptation to a changing environment, which may eventually ensure the persistence of the species in the inner Baltic Sea.

Risk screening of non-native and translocated freshwater fish species in a Mediterranean-type shallow lake: Lake Marmara (West Anatolia)

Risk screening tools to identify species with a high or low risk of invasiveness are being increasingly used for effective management purposes. Amongst the available tools, the Fish Invasiveness Screening Kit (FISK) has been used extensively and successfully in large risk assessment (RA) areas, and was recently upgraded to the new generic tool Aquatic Species Invasiveness Screening Kit (AS-ISK). The aim of the present study was to assess with AS-ISK the invasive potential of introduced non-native and translocated fishes in a Mediterranean-type shallow lake (Lake Marmara) located in west Anatolia (Turkey). Based on independent evaluations of 35 species by two assessors, calibration of AS-ISK resulted in a threshold score of -3.65, which reliably distinguished between potentially invasive (high risk) and potentially non-invasive (medium to low risk) fishes. Of the 35 species assessed, 17 were categorised as ‘low risk’ and included native/endemic and translocated natives, and the remaining 18 as ‘high risk’ and comprised non-natives and translocated natives. Carassius gibelio had the highest score in the Climate Change Assessment section, suggesting that it might potentially impact on the native fish fauna under likely climate change scenarios for the RA area. Some cool water non-native (Oncorhynchus mykiss, Salvelinus fontinalis), translocated native (Luciobarbus lydianus) and endemic species (Ladigesocypris mermere) in the catchment will likely be affected negatively by predicted climate change conditions.

Potential impacts of climate change on flow regime and fish habitat in mountain rivers of the south-western Balkans

The climate change in the Mediterranean area is expected to have significant impacts on the aquatic ecosystems and particular in the mountain rivers and streams that often host important species such as the Salmo farioides, Karaman 1938. These impacts will most possibly affect the habitat availability for various aquatic species resulting to an essential alteration of the water requirements, either for dams or other water abstractions, in order to maintain the essential levels of ecological flow for the rivers. The main scope of this study was to assess potential climate change impacts on the hydrological patterns and typical biota for a south-western Balkan mountain river, the Acheloos. The altered flow regimes under different emission scenarios of the Intergovernmental Panel on Climate Change (IPCC) were estimated using a hydrological model and based on regional climate simulations over the study area. The Indicators of Hydrologic Alteration (IHA) methodology was then used to assess the potential streamflow alterations in the studied river due to predicted climate change conditions. A fish habitat simulation method integrating univariate habitat suitability curves and hydraulic modeling techniques were used to assess the impacts on the relationships between the aquatic biota and hydrological status utilizing a sentinel species, the West Balkan trout. The most prominent effects of the climate change scenarios depict severe flow reductions that are likely to occur especially during the summer flows, changing the duration and depressing the magnitude of the natural low flow conditions. Weighted Usable Area-flow curves indicated the limitation of suitable habitat for the native trout. Finally, this preliminary application highlighted the potential of science-based hydrological and habitat simulation approaches that are relevant to both biological quality elements (fish) and current EU Water policy to serve as efficient tools for the estimation of possible climate change impacts on the south-western Balkan river ecosystems.

Relationships between denitrification gene expression, dissimilatory nitrate reduction to ammonium and nitrous oxide and dinitrogen production in montane grassland soils

The montane grassland soils of Europe store significant amounts of nitrogen (N), and climate change might drive their volatilization due to the stimulation of gaseous nitrous oxide (N2O) and dinitrogen (N2) losses. Hence, a thorough, mechanistic understanding of the processes responsible for N loss and retention such as denitrification and dissimilatory nitrate reduction to ammonium (DNRA) in these soils is urgently needed. Here we aimed to explore the relationships between denitrifier gene abundance and expression with N2 and N2O production and the importance of DNRA versus denitrification in nitrate consumption and N2O production for typical montane grassland soils of Southern Germany. In a laboratory incubation experiment with glucose and nitrate addition, we combined direct measurements of N2O and N2 production with a molecular analysis of the denitrifier communities involved in nitrite, nitric oxide (NO) and N2O reduction and with the quantification of DNRA. The soils originated from a space-for-time climate change experiment, where intact plant-soil mesocosms were exposed for three years either to ambient conditions at a high elevation site (“HE” control treatment) or to predicted climate change conditions (warming, reduced summer precipitation and reduced winter snow cover) by translocation to lower elevation (“LE” climate change treatment).The abundance (DNA) of cnorB genes was significantly reduced in LE soils, whereas the abundance of nosZ genes did not differ between the HE and LE soils. However, the decreased abundance of cnorB genes unexpectedly resulted in slightly increased rather than decreased potential N2O emissions. This effect could be explained by the increased levels of cnorB mRNA and, therefore, the higher physiological activity of the NO reducers in the LE soils. In contrast with the DNA levels, the dynamics of the cnorB mRNA levels followed N2O emission patterns, whereas the nosZ expression was strongly correlated with the N2 emission (R2 = 0.83). The potential rates of DNRA were approximately one-third of the rates of denitrification, and DNRA was not a source for N2O.We conclude that DNRA significantly competes with denitrification in these soils, thus contributing to N conservation. This work demonstrates that the molecular analysis of nosZ gene expression has great potential to contribute to solving the enigmatic problem of understanding N2 loss from soil.