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The environmental impact of climate change is meanwhile not only discussed in the scientific community but also in the general public. However, little is known about the interaction between climate change and pollutants like pesticides. A combination of multiple stressors (e.g. temperature, pollutants, predators) may lead to severe alterations for organisms such as changes in time of reproduction, reproductive success and growth performance, mortality and geographic distribution. The questions if aquatic organisms tend to react more sensitive towards incidents under climate change conditions remains. Therefore, within the present thesis the aquatic ecotoxicological profile of the fungicide pyrimethanil, as an exemplarily anthropogenic used contaminant, was examined.
A large test battery of ecotoxicological standard tests and supplement bioassays with non-model species was conducted to investigate if species-specific or life stage-specific differences occur or if temperature alteration may change the impact of the fungicide. Two of the most sensitive species (Chironomus riparius and Daphnia magna) were used to investigate the acute and chronic thermal dependence of pyrimethanil effects. The results clearly depict that the ecotoxicity of pyrimethanil at optimal thermal conditions did not depend on the trophic level, but was species-specific. With regard to EC10 values the acute pyrimethanil toxicity on C. riparius increased with higher temperature (6.78 mg L-1 at 14°C and 3.06 mg L-1 at 26°C). The chronic response of D. magna to the NOEC (no observed effect concentration) of the fungicide (0.5 mg L-1) was examined in an experiment which lasted for several generations under three simulated near-natural temperature regimes (‘cold year, today’ (11 to 22.7°C), ‘warm year, today’ (14 to 25.2°C) and ‘warm year, 2080’ (16.5 to 28.1°C)). A pyrimethanil-induced mortality increase was buffered by the strongly related increase of the general reproductive capacity, while population growth was stronger influenced by temperature than by the fungicide. At a further pyrimethanil concentration (LOEC – lowest observed effect concentration: 1 mg L-1), a second generation could not be established by D. magna under all thermal regimes.
Besides daphnids, the midge C. riparius was used for a second multigeneration study. In a bifactorial test design it was tested if climate change conditions alter or affect the impact of a low fungicide concentration on life history and genetic diversity. The NOAEC/2 (half of the no observed adverse effect concentration derived from a standard toxicity test) was used as a low pyrimethanil concentration to which laboratory populations of the midges were chronically exposed under the mentioned temperature scenarios. During the 140-day-multigeneration study, survival, emergence, reproduction, population growth, and genetic diversity of C. riparius were analyzed. The results reveal that high temperatures and pyrimethanil act synergistically on life history parameters of C. riparius. In simulated present-day scenarios, a NOAEC/2 of pyrimethanil provoked only slight to moderate beneficial or adverse effects. In contrast, an exposure to a NOAEC/2 concentration of pyrimethanil at a thermal situation likely for a summer under the future expactations uncovered adverse effects on mortality and population growth rate. In addition, genetic diversity was considerably reduced by pyrimethanil in the ‘warm year, 2080’ scenario, but only slightly under current climatic conditions. The multigeneration studies under near-natural thermal conditions indicate that not only the impact of climate change, but also low concentrations of pesticides may pose a reasonable risk for aquatic invertebrates in the future. This clearly shows that thermal and multigenerational effects should be considered when appraising the ecotoxicity of pesticides and assessing their future risk for the environment.
In addition to temperature further multiple abiotic and biotic stressors alterate pollutant effects. Moreover, to better discriminate and understand the intrinsic and environmental correlates of changing aquatic ecosystems, it was experimentally unraveled how the effects of a low-dose of pyrimethanil on daphnids becomes modified by different temperatures (15°C, 20°C, 25°C) and in the presence/ absence of predator kairomones of Chaoborus flavicans larvae. The usage of a fractional multifactorial test design provided the possibility to investigate the individual growth, reproduction and population growth rate of Daphnia pulex via different exposure routes to the fungicide pyrimethanil at an environmentally relevant concentration (0.05 mg L-1) - either directly (via the water phase), indirectly (via algae food), dually (via water and food) or for multiple generations (fungicide treated source population).
The number of neonates increased with increasing temperatures. At a temperature of 25°C no significant differences between the individual treatment groups were observed although the growth was overall inhibited due to pyrimethanil. Besides, at 15 and 20°C it is obvious that daphnids which were fed with contaminated algae had the lowest reproduction and growth rate. The obtained results clearly demonstrate that multiple stress factors can modify the response of daphnids to pollutants. The exposure routes of the contaminant are of minor importance, while temperature and the presence of a predator are the dominant factors impacting the reproduction of D. pulex. It can be concluded that low concentrations of pyrimethanil may disturb the zooplankton community at suboptimal temperature conditions, but the effects will become masked if chaoborid larvae are present. Therefore it seems necessary to observe prospectively if the combination of several stress factors like pesticide exposure and suboptimal temperature may influence the life history and sensitivity of several aquatic invertebrates differently.
Besides standard test organisms it is inevitable to conduct test with aquatic invertebrate which are not yet considered regularly in ecotoxicological experiments. For example molluscs represent one of the largest phyla of macroinvertebrates with more than 100.000 species, being ecologically and economically important. Therefore, within the present study embryo, juvenile, half- and full-life cycle toxicity tests with the snail Physella acuta were performed to investigate the impact of pollutants on various life stages. Different concentrations of pyrimethanil (0.06-0.5 or 1.0 mg L-1) assessed at three temperatures (15°C, 20°C, 25°C) revealed that pyrimethanil caused concentration-dependent effects independent of temperature. Interestingly, the ecotoxicity of pyrimethanil was higher at lower temperature for the embryo hatching and F1 reproduction, but its ecotoxicity for the growth of juveniles and the F0 reproduction increased with increasing temperature. More specifically, it could have been observed that especially during the reproduction test high mortality rates occurred at the highest concentration of 1 mg L-1 at all temperatures. Due to high mortality rates no snails were available for the F1 at the highest concentrations (0.5 and 1.0 mg L-1). Compared to the F0, overall more egg masses were produced in the F1, being all fertile and no mortality occurred. For the F1-generation the strongest pyrimethanil effects were detected at 15°C. A comparison of effect concentrations between both generations showed that the F1 is more sensitive than the F0.
These results indicate that an exposure over more than one generation may give a better overview of the impact of xenobiotics. With the establishment of an embryo and reproduction test under different temperatures and various concentrations of pyrimethanil with P. acuta we could successfully show that molluscs can respond more sensitive than model organisms and that both, chemical and thermal stressor strongly influence the behaviour of the pulmonates. It can be concluded that the high susceptibility for the fungicide observed in gastropods clearly demonstrates the complexity of pesticide-temperature interactions and the challenge to draw conclusions for the ecotoxicological risk assessment of pesticides under the impact of global climate change.
Since the 1980s, advances in wastewater treatment technology have led to considerably improved surface water quality in the urban areas of many high income countries. However, trace concentrations of organic wastewater-associated contaminants may still pose a key environmental hazard impairing the ecological quality of surface waters. To identify key impact factors, we analyzed the effects of a wide range of anthropogenic and environmental variables on the aquatic macroinvertebrate community. We assessed ecological water quality at 26 sampling sites in four urban German lowland river systems with a 0–100% load of state-of-the-art biological activated sludge treated wastewater. The chemical analysis suite comprised 12 organic contaminants (five phosphor organic flame retardants, two musk fragrances, bisphenol A, nonylphenol, octylphenol, diethyltoluamide, terbutryn), 16 polycyclic aromatic hydrocarbons, and 12 heavy metals. Non-metric multidimensional scaling identified organic contaminants that are mainly wastewater-associated (i.e., phosphor organic flame retardants, musk fragrances, and diethyltoluamide) as a major impact variable on macroinvertebrate species composition. The structural degradation of streams was also identified as a significant factor. Multiple linear regression models revealed a significant impact of organic contaminants on invertebrate populations, in particular on Ephemeroptera, Plecoptera, and Trichoptera species. Spearman rank correlation analyses confirmed wastewater-associated organic contaminants as the most significant variable negatively impacting the biodiversity of sensitive macroinvertebrate species. In addition to increased aquatic pollution with organic contaminants, a greater wastewater fraction was accompanied by a slight decrease in oxygen concentration and an increase in salinity. This study highlights the importance of reducing the wastewater-associated impact on surface waters. For aquatic ecosystems in urban areas this would lead to: (i) improvement of the ecological integrity, (ii) reduction of biodiversity loss, and (iii) faster achievement of objectives of legislative requirements, e.g., the European Water Framework Directive.
Despite numerous large-scale phylogenomic studies, certain parts of the mammalian tree are extraordinarily difficult to resolve. We used the coding regions from 19 completely sequenced genomes to study the relationships within the super-clade Euarchontoglires (Primates, Rodentia, Lagomorpha, Dermoptera and Scandentia) because the placement of Scandentia within this clade is controversial. The difficulty in resolving this issue is due to the short time spans between the early divergences of Euarchontoglires, which may cause incongruent gene trees. The conflict in the data can be depicted by network analyses and the contentious relationships are best reconstructed by coalescent-based analyses. This method is expected to be superior to analyses of concatenated data in reconstructing a species tree from numerous gene trees. The total concatenated dataset used to study the relationships in this group comprises 5,875 protein-coding genes (9,799,170 nucleotides) from all orders except Dermoptera (flying lemurs). Reconstruction of the species tree from 1,006 gene trees using coalescent models placed Scandentia as sister group to the primates, which is in agreement with maximum likelihood analyses of concatenated nucleotide sequence data. Additionally, both analytical approaches favoured the Tarsier to be sister taxon to Anthropoidea, thus belonging to the Haplorrhine clade. When divergence times are short such as in radiations over periods of a few million years, even genome scale analyses struggle to resolve phylogenetic relationships. On these short branches processes such as incomplete lineage sorting and possibly hybridization occur and make it preferable to base phylogenomic analyses on coalescent methods.
Background: Elucidating the genomic basis of adaptation and speciation is a major challenge in natural systems with large quantities of environmental and phenotypic data, mostly because of the scarcity of genomic resources for non-model organisms. The Atlantic molly (Poecilia mexicana, Poeciliidae) is a small livebearing fish that has been extensively studied for evolutionary ecology research, particularly because this species has repeatedly colonized extreme environments in the form of caves and toxic hydrogen sulfide containing springs. In such extreme environments, populations show strong patterns of adaptive trait divergence and the emergence of reproductive isolation. Here, we used RNA-sequencing to assemble and annotate the first transcriptome of P. mexicana to facilitate ecological genomics studies in the future and aid the identification of genes underlying adaptation and speciation in the system.
Description: We provide the first annotated reference transcriptome of P. mexicana. Our transcriptome shows high congruence with other published fish transcriptomes, including that of the guppy, medaka, zebrafish, and stickleback. Transcriptome annotation uncovered the presence of candidate genes relevant in the study of adaptation to extreme environments. We describe general and oxidative stress response genes as well as genes involved in pathways induced by hypoxia or involved in sulfide metabolism. To facilitate future comparative analyses, we also conducted quantitative comparisons between P. mexicana from different river drainages. 106,524 single nucleotide polymorphisms were detected in our dataset, including potential markers that are putatively fixed across drainages. Furthermore, specimens from different drainages exhibited some consistent differences in gene regulation.
Conclusions: Our study provides a valuable genomic resource to study the molecular underpinnings of adaptation to extreme environments in replicated sulfide spring and cave environments. In addition, this study adds to the increasing number of genomic resources in the family Poeciliidae, which are widely used in comparative analyses of behavior, ecology, evolution, and medical genetics.
Ambrosia artemisiifolia L., native to North America, is a problematic invasive species, because of its highly allergenic pollen. The species is expected to expand its range due to climate change. By means of ecological niche modelling (ENM), we predict habitat suitability for A. artemisiifolia in Europe under current and future climatic conditions. Overall, we compared the performance and results of 16 algorithms commonly applied in ENM. As occurrence records of invasive species may be dominated by sampling bias, we also used data from the native range. To assess the quality of the modelling approaches we assembled a new map of current occurrences of A. artemisiifolia in Europe. Our results show that ENM yields a good estimation of the potential range of A. artemisiifolia in Europe only when using the North American data. A strong sampling bias in the European Global Biodiversity Information Facility (GBIF) data for A. artemisiifolia causes unrealistic results. Using the North American data reflects the realized European distribution very well. All models predict an enlargement and a northwards shift of potential range in Central and Northern Europe during the next decades. Climate warming will lead to an increase and northwards shift of A. artemisiifolia in Europe.
BACKGROUND: Current biodiversity patterns are considered largely the result of past climatic and tectonic changes. In an integrative approach, we combine taxonomic and phylogenetic hypotheses to analyze temporal and geographic diversification of epigean (Carychium) and subterranean (Zospeum) evolutionary lineages in Carychiidae (Eupulmonata, Ellobioidea). We explicitly test three hypotheses: 1) morphospecies encompass unrecognized evolutionary lineages, 2) limited dispersal results in a close genetic relationship of geographical proximally distributed taxa and 3) major climatic and tectonic events had an impact on lineage diversification within Carychiidae.
RESULTS: Initial morphospecies assignments were investigated by different molecular delimitation approaches (threshold, ABGD, GMYC and SP). Despite a conservative delimitation strategy, carychiid morphospecies comprise a great number of unrecognized evolutionary lineages. We attribute this phenomenon to historic underestimation of morphological stasis and phenotypic variability amongst lineages. The first molecular phylogenetic hypothesis for the Carychiidae (based on COI, 16S and H3) reveals Carychium and Zospeum to be reciprocally monophyletic. Geographical proximally distributed lineages are often closely related. The temporal diversification of Carychiidae is best described by a constant rate model of diversification. The evolution of Carychiidae is characterized by relatively few (long distance) colonization events. We find support for an Asian origin of Carychium. Zospeum may have arrived in Europe before extant members of Carychium. Distantly related Carychium clades inhabit a wide spectrum of the available bioclimatic niche and demonstrate considerable niche overlap.
CONCLUSIONS: Carychiid taxonomy is in dire need of revision. An inferred wide distribution and variable phenotype suggest underestimated diversity in Zospeum. Several Carychium morphospecies are results of past taxonomic lumping. By collecting populations at their type locality, molecular investigations are able to link historic morphospecies assignments to their respective evolutionary lineage. We propose that rare founder populations initially colonized a continent or cave system. Subsequent passive dispersal into adjacent areas led to in situ pan-continental or mountain range diversifications. Major environmental changes did not influence carychiid diversification. However, certain molecular delimitation methods indicated a recent decrease in diversification rate. We attribute this decrease to protracted speciation.
Foliar fungal communities of plants are diverse and ubiquitous. In grasses endophytes may increase host fitness; in trees, their ecological roles are poorly understood. We investigated whether the genotype of the host tree influences community structure of foliar fungi. We sampled leaves from genotyped balsam poplars from across the species' range, and applied 454 amplicon sequencing to characterize foliar fungal communities. At the time of the sampling the poplars had been growing in a common garden for two years. We found diverse fungal communities associated with the poplar leaves. Linear discriminant analysis and generalized linear models showed that host genotypes had a structuring effect on the composition of foliar fungal communities. The observed patterns may be explained by a filtering mechanism which allows the trees to selectively recruit fungal strains from the environment. Alternatively, host genotype-specific fungal communities may be present in the tree systemically, and persist in the host even after two clonal reproductions. Both scenarios are consistent with host tree adaptation to specific foliar fungal communities and suggest that there is a functional basis for the strong biotic interaction.
Non-indigenous species that become invasive are one of the main drivers of biodiversity loss worldwide. In various freshwater systems in Europe, populations of native amphipods and fish are progressively displaced by highly adaptive non-indigenous species that can perform explosive range extensions. A total of 40 Ponto-Caspian round gobies Neogobius melanostomus from the Rhine River near Düsseldorf, North Rhine-Westphalia, Germany, were examined for metazoan parasites and feeding ecology. Three metazoan parasite species were found: two Nematoda and one Acanthocephala. The two Nematoda, Raphidascaris acus and Paracuaria adunca, had a low prevalence of 2.5%. The Acanthocephala, Pomphorhynchus tereticollis, was the predominant parasite species, reaching a level of 90.0% prevalence in the larval stage, correlated with fish size. In addition, four invasive amphipod species, Corophium curvispinum (435 specimens), Dikerogammarus villosus (5,454), Echinogammarus trichiatus (2,695) and Orchestia cavimana (1,448) were trapped at the sampling site. Only D. villosus was infected with P. tereticollis at a prevalence of 0.04%. The invasive goby N. melanostomus mainly preys on these non-indigenous amphipods, and may have replaced native amphipods in the transmission of P. tereticollis into the vertebrate paratenic host. This study gives insight into a potential parasite-host system that consists mainly of invasive species, such as the Ponto-Caspian fish and amphipods in the Rhine. We discuss prospective distribution and migration pathways of non-indigenous vertebrate (round goby) and invertebrates (amphipods) under special consideration of parasite dispersal.
There is increasing evidence that climate change will have a severe impact on species’ distributions by altering the climatic conditions within their present ranges. Especially species inhabiting stream ecosystems are expected to be strongly affected due to warming temperatures and changes in precipitation patterns. The aim of this thesis was to
investigate how distributions of aquatic insects, i.e., benthic stream macroinvertebrates would be impacted by warming climates. The methods comprised of an ensemble forecasting technique based on species distribution models (SDMs) and climate change scenarios of the Intergovernmental Panel on Climate Change of the year 2080. Future model projections were generated for a wide variety of species from a number of taxonomic orders for two spatial scales: a stream network within the lower mountain ranges of Germany, and the entire territory across Europe. In addition, the effect of the modelling technique on habitat suitability projections was investigated by modifying the choice of study area (continuous area vs. stream network) and the choice of predictors (standard vs. corrected set).
Projections of future habitat suitability showed that potential climate-change impacts would be dependent on species’ thermal preferences, and with a similar pattern for both spatial scales. Future habitat suitability was projected to remain for most or all of the modelled species, and species were projected to track their climatically suitable conditions by shifting uphill along the river continuum within the lower mountain ranges, and into a north-easterly direction across Europe. Cold-adapted headwater and high-latitude species were projected to lose suitable habitats, whereas gains would be expected for warm-adapted river and low-latitude species along the river continuum and across Europe, respectively. Additionally, habitat specialist species in terms of endemics of the Iberian Peninsula were identified as potential climate-change losers, highlighting their restricted habitat availability and therefore vulnerability to warming climates.
The main findings of this thesis underline the high susceptibility of stream macroinvertebrates to ongoing climate change, and give insights into patterns of possible consequences due to changes in species’ habitat suitability. Concerning the methodology, a clear recommendation can be given for future modelling approaches of stream macroinvertebrates by building models within a stream network and with a careful choice of environmental predictors, to reduce uncertainties and thus to improve model projections.
Before the advent of molecular phylogenetics, species concepts in the downy mildews, an economically important group of obligate biotrophic oomycete pathogens, have mostly been based upon host range and morphology. While molecular phylogenetic studies have confirmed a narrow host range for many downy mildew species, others, like Pseudoperonospora cubensis affect even different genera. Although often morphological differences were found for new, phylogenetically distinct species, uncertainty prevails regarding their host ranges, especially regarding related plants that have been reported as downy mildew hosts, but were not included in the phylogenetic studies. In these cases, the basis for deciding if the divergence in some morphological characters can be deemed sufficient for designation as separate species is uncertain, as observed morphological divergence could be due to different host matrices colonised. The broad host range of P. cubensis (ca. 60 host species) renders this pathogen an ideal model organism for the investigation of morphological variations in relation to the host matrix and to evaluate which characteristics are best indicators for conspecificity or distinctiveness. On the basis of twelve morphological characterisitcs and a set of twelve cucurbits from five different Cucurbitaceae tribes, including the two species, Cyclanthera pedata and Thladiantha dubia, hitherto not reported as hosts of P. cubensis, a significant influence of the host matrix on pathogen morphology was found. Given the high intraspecific variation of some characteristics, also their plasticity has to be taken into account. The implications for morphological species determination and the confidence limits of morphological characteristics are discussed. For species delimitations in Pseudoperonospora it is shown that the ratio of the height of the first ramification to the sporangiophore length, ratio of the longer to the shorter ultimate branchlet, and especially the length and width of sporangia, as well as, with some reservations, their ratio, are the most suitable characteristics for species delimitation.
Background: Hybridisation is presumed to be an important mechanism in plant speciation and a creative evolutionary force often accompanied by polyploidisation and in some cases by apomixis. The Potentilla collina group constitutes a particularly suitable model system to study these phenomena as it is morphologically extensively variable, exclusively polyploid and expresses apomixis. In the present study, the alpine taxon Potentilla alpicola has been chosen in order to study its presumed hybrid origin, identify underlying evolutionary processes and infer the discreteness or taxonomic value of hybrid forms.
Results: Combined analysis of AFLP, cpDNA sequences and ploidy level variation revealed a hybrid origin of the P. alpicola populations from South Tyrol (Italy) resulting from crosses between P. pusilla and two cytotypes of P. argentea. Hybrids were locally sympatric with at least one of the parental forms. Three lineages of different evolutionary origin comprising two ploidy levels were identified within P. alpicola. The lineages differed in parentage and the complexity of the evolutionary process. A geographically wide-spread lineage thus contrasted with locally distributed lineages of different origins. Populations of P. collina studied in addition, have been regarded rather as recent derivatives of the hexaploid P. argentea. The observation of clones within both P. alpicola and P. collina suggested a possible apomictic mode of reproduction.
Conclusions: Different hybridisation scenarios taking place on geographically small scales resulted in viable progeny presumably stabilised by apomixis. The case study of P. alpicola supports that these processes played a significant role in the creation of polymorphism in the genus Potentilla. However, multiple origin of hybrids and backcrossing are considered to produce a variety of evolutionary spontaneous forms existing aside of reproductively stabilised, established lineages.
In den vergangenen Jahren gab es verschiedene Initiativen, die auf die unzureichende Fördersituation der Schadstoffbezogenen Umweltwissenschaften in der Bundesrepublik Deutschland aufmerksam gemacht haben. Um eine objektive Analyse über die Fördersituation der Ökotoxikologie und Umweltchemie in Deutschland zu erhalten, wurde eine anonyme Online-Befragung ausgearbeitet. Mit Unterstützung der Society of Environmental Toxicology and Chemistry (SETAC) – German Language Branch und der Gesellschaft Deutscher Chemiker (GDCh) – Fachgruppe für Umweltchemie und Ökotoxikologie wurde eine Einladung zur Teilnahme an der Befragung an alle Mitglieder dieser beiden maßgeblichen Verbände der Ökotoxikologie und Umweltchemie im deutschsprachigen Raum versendet. Nur leitende Mitarbeiter aus den Bereichen Forschung, Behörden und Industrie sollten an der Befragung teilnehmen. Die Befragung gliedert sich in eine Sektion zur sozioökonomischen Charakterisierung der Teilnehmer, eine zur Förderung der Forschung durch die DFG und eine zur Förderung durch andere Geldgeber. Insgesamt haben 71 Wissenschaftler und Wissenschaftlerinnen in leitenden Positionen aus verschiedenen Sparten an der Befragung teilgenommen. Die Ergebnisse zeigen, dass die Teilnehmer als sehr leistungsstark eingestuft werden können. 48,5 % der Befragten hatten bereits einen Antrag bei der DFG gestellt. Ein Drittel der Befragten gaben an, eine Förderung durch die DFG erhalten zu haben. 64 % sind mit der Förderung Schadstoffbezogener Umweltwissenschaften durch die DFG nicht zufrieden, nur 7 % sind zufrieden. Es zeigte sich, dass die Anträge insgesamt sehr heterogen auf verschiedene Fachbereiche der DFG verteilt sind. Geowissenschaften, Wasserforschung und Chemie nehmen die ersten Ränge ein, vor Biologie und Ökologie. Im Gegensatz dazu gaben 91,2 % der Befragten an, dass Sie bereits Drittmittelanträge bei anderen Förderinstitutionen (außer der DFG) gestellt haben, und 83,6 % wurden bereits entsprechende Drittmittelanträge bewilligt. 62,3 % der Befragten sind der Meinung, dass sich die Fördersituation für die Schadstoffbezogenen Umweltwissenschaften in den letzten Jahren insgesamt verschlechtert oder sogar deutlich verschlechtert hat. Der überwiegende Anteil der Befragten (60,9 %) ist mit der Fördersituation durch Drittmittelgeber unzufrieden, nur 10,9 % sind damit zufrieden. Auf die Frage „Ist die Forschungsförderung im europäischen Ausland insgesamt besser als in Deutschland?“ antworteten 30 % mit „ja“, 9 % mit „nein“ und 61 % mit „ich weiß nicht“. Zusammenfassend ergab die Befragung, dass die Fördersituation der Ökotoxikologie und Umweltchemie in Deutschland insgesamt als steigerungsbedürftig, bei der DFG jedoch als problematisch zu bewerten ist. Die auffällige Unterrepräsentation der DFG im Vergleich zu anderen Drittmittelgebern verdeutlicht, dass die wichtigste Förderinstitution Deutschlands den Bedürfnissen der Schadstoffbezogenen Umweltwissenschaften nicht hinreichend Rechnung trägt. Insbesondere die Antworten auf die offenen Fragen bezüglich Verbesserungsmöglichkeiten der Forschungsförderung sollten als Grundlage für einen offenen Dialog der Schadstoffbezogenen Umweltforschung mit den Drittmittelgebern DFG, BMBF und DBU bzw. den entsprechenden Institutionen in CH und A genutzt werden.
Although it has been suggested that temperature increase may alter the toxic potential of environmental pollutants, few studies have investigated the potential risk of chemical stressors for wildlife under Global Climate Change (GCC) impact. We applied a bifactorial multigeneration study in order to test if GCC conditions alter the effects of low pesticide concentrations on life history and genetic diversity of the aquatic model organism Chironomus riparius. Experimental populations of the species were chronically exposed to a low concentration of the fungicide pyrimethanil (half of the no-observed-adverse-effect concentration: NOAEC/2) under two dynamic present-day temperature simulations (11.0–22.7°C; 14.0–25.2°C) and one future scenario (16.5–28.1°C). During the 140-day multigeneration study, survival, emergence, reproduction, population growth, and genetic diversity of C. riparius were analyzed. Our results reveal that high temperature and pyrimethanil act synergistically on the midge C. riparius. In simulated present-day scenarios, a NOAEC/2 of pyrimethanil as derived from a life-cycle toxicity test provoked only slight-to-moderate beneficial or adverse effects on C. riparius. In contrast, exposure to a NOAEC/2 concentration of pyrimethanil at a thermal situation likely for a summer under GCC conditions uncovered adverse effects on mortality and population growth rate. In addition, genetic diversity was considerably reduced by pyrimethanil in the future scenario, but only slightly under current climatic conditions. Our multigeneration study under near-natural (climatic) conditions indicates that not only the impact of climate change, but also low concentrations of pesticides may pose a reasonable risk for aquatic insects in future.
We study how species richness of arthropods relates to theories concerning net primary productivity, ambient energy, water-energy dynamics and spatial environmental heterogeneity. We use two datasets of arthropod richness with similar spatial extents (Scandinavia to Mediterranean), but contrasting spatial grain (local habitat and country). Samples of ground-dwelling spiders, beetles, bugs and ants were collected from 32 paired habitats at 16 locations across Europe. Species richness of these taxonomic groups was also determined for 25 European countries based on the Fauna Europaea database. We tested effects of net primary productivity (NPP), annual mean temperature (T), annual rainfall (R) and potential evapotranspiration of the coldest month (PETmin) on species richness and turnover. Spatial environmental heterogeneity within countries was considered by including the ranges of NPP, T, R and PETmin. At the local habitat grain, relationships between species richness and environmental variables differed strongly between taxa and trophic groups. However, species turnover across locations was strongly correlated with differences in T. At the country grain, species richness was significantly correlated with environmental variables from all four theories. In particular, species richness within countries increased strongly with spatial heterogeneity in T. The importance of spatial heterogeneity in T for both species turnover across locations and for species richness within countries suggests that the temperature niche is an important determinant of arthropod diversity. We suggest that, unless climatic heterogeneity is constant across sampling units, coarse-grained studies should always account for environmental heterogeneity as a predictor of arthropod species richness, just as studies with variable area of sampling units routinely consider area.
The wild silkmoth genus Sinobirma Bryk, 1944 is a poorly known monotypic taxon from the eastern end of the Himalaya Range. It was convincingly proposed to be closely related to some members of an exclusively Afro-tropical group of Saturniidae, but its biogeographical and evolutionary history remains enigmatic. After examining recently collected material from Tibet, northern India, and northeastern Myanmar, we realized that this unique species, S. malaisei Bryk, 1944 only known so far from a few specimens and from a very restricted area near the border between north-eastern Myanmar and the Yunnan province of China, may in fact belong to a group of closely related cryptic species. In this work, we combined morphological comparative study, DNA barcoding, and the sequences of a nuclear marker (D2 expansion segment of the 28S rRNA gene) to unequivocally delimit three distinct species in the genus Sinobirma, of which two are described as new to science: S. myanmarensis sp. n. and S. bouyeri sp. n. An informative DNA barcode sequence was obtained from the female holotype of S. malaisei—collected in 1934—ensuring the proper assignation of this name to the newly collected and studied specimens. Our findings represent another example of the potential of coupling traditional taxonomy and DNA barcoding for revealing and solving difficult cases of cryptic diversity. This approach is now being generalized to the world fauna of Saturniidae, with the participation of most of the taxonomists studying these moths.
During field work along a transect in the Cordillera Central of western Panama between 2008 and 2010, we detected several populations of amphibian species which are considered as “Endangered” or “Critically Endangered” by the IUCN. Some of these species had suffered from serious population declines, probably due to chytridiomycosis, but all are generally threatened by habitat loss. We detected 53% of the Endangered and 56% of the Critically Endangered amphibian species that have previously been reported from within the investigated area. We report on findings of species that have not been found in Panama for many years, and provide locality data of newly discovered populations. There is a need to create a new protected area in the Cerro Colorado area of the Serranía de Tabasará, where we found 15% of the Endangered and Critically Endangered amphibian species known to Panama.
The Arabidopsis arenosa complex is closely related to the model plant Arabidopsis thaliana. Species and subspecies in the complex are mainly biennial, predominantly outcrossing, herbaceous, and with a distribution range covering most parts of latitudes and the eastern reaches of Europe. In this study we present the first comprehensive evolutionary history of the A. arenosa species complex, covering its natural range, by using chromosome counts, nuclear AFLP data, and a maternally inherited marker from the chloroplast genome [trnL intron (trnL) and trnL/F intergenic spacer (trnL/F-IGS) of tRNALeu and tRNAPhe, respectively]. We unravel the broad-scale cytogeographic and phylogeographic patterns of diploids and tetraploids. Diploid cytotypes were exclusively found on the Balkan Peninsula and in the Carpathians while tetraploid cytotypes were found throughout the remaining distribution range of the A. arenosa complex. Three centers of genetic diversity were identified: the Balkan Peninsula, the Carpathians, and the unglaciated Eastern and Southeastern Alps. All three could have served as long-term refugia during Pleistocene climate oscillations. We hypothesize that the Western Carpathians were and still are the cradle of speciation within the A. arenosa complex due to the high species number and genetic diversity and the concurrence of both cytotypes there.
Sponges play a key role in Antarctic marine benthic community structure and dynamics and are often a dominant component of many Southern Ocean benthic communities. Understanding the drivers of sponge distribution in Antarctica enables us to understand many of general benthic biodiversity patterns in the region. The sponges of the Antarctic and neighbouring oceanographic regions were assessed for species richness and biogeographic patterns using over 8,800 distribution records. Species-rich regions include the Antarctic Peninsula, South Shetland Islands, South Georgia, Eastern Weddell Sea, Kerguelen Plateau, Falkland Islands and north New Zealand. Sampling intensity varied greatly within the study area, with sampling hotspots found at the Antarctic Peninsula, South Georgia, north New Zealand and Tierra del Fuego, with limited sampling in the Bellingshausen and Amundsen seas in the Southern Ocean. In contrast to previous studies we found that eurybathy and circumpolar distributions are important but not dominant characteristics in Antarctic sponges. Overall Antarctic sponge species endemism is ~43%, with a higher level for the class Hexactinellida (68%). Endemism levels are lower than previous estimates, but still indicate the importance of the Polar Front in isolating the Southern Ocean fauna. Nineteen distinct sponge distribution patterns were found, ranging from regional endemics to cosmopolitan species. A single, distinct Antarctic demosponge fauna is found to encompass all areas within the Polar Front, and the sub-Antarctic regions of the Kerguelen Plateau and Macquarie Island. Biogeographical analyses indicate stronger faunal links between Antarctica and South America, with little evidence of links between Antarctica and South Africa, Southern Australia or New Zealand. We conclude that the biogeographic and species distribution patterns observed are largely driven by the Antarctic Circumpolar Current and the timing of past continent connectivity.