570 Biowissenschaften; Biologie
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The loss of biodiversity is recognised on a global scale and also in the anthropogenic landscapes used for agriculture, now covering almost 50% of the global terrestrial land surface. In agriculture pesticides, biologically active chemicals are deliberately distributed to control pests, disease and weeds in the cropped areas. The quantification of remaining semi-naturals structures such as field margins and hedges is a prerequisite to understand the impact of pesticides on biodiversity, since these structures represent habitats for many organisms in agricultural landscapes. The presence of organisms in these habitats and crops is required to obtain an estimate of their potential pesticide exposure. In this text I provide studies on animal groups so far not addressed in risk assessment procedures for the regulation of pesticides such as amphibians, moths and bats. For all groups it becomes apparent that they are present in agricultural landscapes and potentially coincide with pesticide applications indicating a risk. Risk quantification also requires data on the sensitivity of organisms and here data for plants, amphibians and bees are presented. Effects translating to community level were studied for herbicide, insecticide and fertiliser effects in a natural system. After three years the treatments resulted in simplified plant communities with lower species numbers and a reduction in flowering plants. This reduction of flowers is used as an example for an indirect effect and was especially obvious for the effect of an herbicide on the common buttercup. Sublethal herbicide effects for a plant translated in an impact on feeding caterpillars, indicating a reduction in food quality. Insecticide inputs realistic for field margins also reduced moth pollination of white champion flowers by 30%. These indirect effects by distortions of food web characteristics are playing a critical role to understand declines in organism groups, however so far are not accounted for in pesticide risk assessment schemes. The current intense use of pesticides in agriculture and their inherent toxicity may lead to a chemical landscape fragmentation, where populations may not be connected anymore. Source-sink dynamics are important ecological processes and as a final result not only population size but also genetic population structure might be affected. Including potential pesticide impacts as costs in a model for amphibians migrating to breeding ponds in vineyards in Rhineland-Palatinate indicated the isolation of investigated populations. A first validation by analyzing the population structure of the European common frog confirmed the model prediction for some sites. For the regulation of pesticides in Europe a risk assessment is required and for the organisms of the terrestrial habitat a multitude of guidance documents is in place or is recently developed or improved. The results of the presented research indicate that wild plants and especially their reproductive flower stage are highly sensitive and risks are underestimated. Population recovery of arthropods needs a reevaluation at landscape scale and the addition of amphibian risk assessment in regulation procedures is suggested. However, developing or adopting risk assessment procedures and test systems is a time consuming task and therefore the establishment of risk management options is a pragmatic alternative with immediate effects. Artificial wetlands in the agricultural landscape proved to be important foraging sites for bats and their creation could mitigate negative pesticide effects. The integration of direct and indirect effects in a risk assessment scheme for all organism groups addressing also landscape scale and pesticide mixtures requires a long developing time. The establishment of model landscapes where management options and integrated pest management are applied on a larger scale would allow us to study pesticide effects in a realistic scenario and to develop an approach for the agriculture of the future.
The largest population of the anadromous Allis shad (A. alosa) of the 19th century was found in River Rhine and has to be considered extinct today. To facilitate the return of A. alosa into River Rhine an EU LIFE-project was initiated in 2007. The overall objective of this thesis was to assist aquaculture and stocking-measures at River Rhine, as well as to support restoration and conservation of populations of Allis shad in Europe.
By culturing the free-swimming nematode T. aceti in a solution of cider vinegar we developed a cost-effective live food organism for the larviculture of fish. As indicated by experiments with C. maraena, T. aceti cannot be regarded as an alternative to Artemia nauplii. However it has to be considered a suitable supplemental feed in the early rearing of C. maraena by providing essential fatty acids, thereby optimizing growth.
Also mass-marking practices with Oxytetracycline, as they are applied in the restocking of Allis shad have been evaluated. In experiments with D. rerio we demonstrated that water hardness can detrimentally affect mortality during marking and has to be considered crucial in the development of marking protocols for freshwater fish.
In order to get independent from wild spawners an ex-situ Broodstock-facility for Allis shad was established in 2011. Upon examination of two complete year classes of this broodstock, we found a high prevalence of various malformations, which could be traced back to distinct cysts developing one month post hatch. Despite applying a variety of clinical tests we could not identify any infectious agents causing these malformations. The observed malformations are probably a consequence of suboptimal feeding practices or the properties of the physio-chemical rearing environment.
The decline of stocks of A. alosa in Europe has been largely explained with the increase of river temperatures as a consequence of global warming. By investigating the temperature physiology of larval Allis shad we demonstrated that A. alosa ranges among the most thermo-tolerant species in Europe and that correlations between rising temperatures and the disappearance of this species have to be understood in a synecological context and by integrating a variety of stressors other than temperature. By capturing and examining juvenile and adult Allis shad from River Rhine, we demonstrated the first natural reproduction of A. alosa in River Rhine since nearly 100 years and the success of stocking measures within the framework of the LIFE project.
Non-Consumptive Effects of Spiders and Ants: Does Fear Matter in Terrestrial Interaction Webs?
(2014)
Most animals suffer from predators. Besides killing prey, predators can affect prey physiology, morphology and behaviour. Spiders are among the most diverse and frequent predators in terrestrial ecosystems. Our behavioural arena experiments revealed that behavioural changes under spider predation risk are relatively scarce among arthropods. Wood crickets (Nemobius sylvestris), in particular, changed their behaviour in response to cues of various spider species. Thereby, more common and relatively larger spider species induced stronger antipredator behaviour in crickets.
Behavioural changes under predation risk are expected to enhance predator avoidance, but they come at a cost. Crickets previously confronted with cues of the nursery web spider (Pisaura mirabilis) were indeed more successful in avoiding predation. Surprisingly, crickets slightly increased food uptake and lost less weight under predation risk, indicating that crickets are able to compensate for short-term cost under predation risk. In a following plant choice experiment, crickets strongly avoided plants bearing spider cues, which in turn reduced the herbivory on the respective plants.
Similar to spiders, ants are ubiquitous predators and can have a strong impact on herbivores, but also on other predators. Juvenile spiders increased their propensity for long-distance dispersal if exposed to ant cues. Thus, spiders use this passive dispersal through the air (ballooning) to avoid ants and colonise new habitats.
In a field experiment, we compared arthropod colonisation between plants bearing cues of the nursery web spider and cue-free plants. We followed herbivory during the experimental period and sampled the arthropod community on the plants. In accordance with the plant choice experiment, herbivory was reduced on plants bearing spider cues. In addition, spider cues led to changes in the arthropod community: smaller spiders and black garden ants (Lasius niger) avoided plants bearing spider cues. In contrast, common red ants (Myrmica rubra) increased the recruitment of workers, possibly to protect their aphids.
Although behavioural changes were relatively rare on filter papers bearing spider cues, more natural experimental setups revealed strong and far-reaching effects of predation risk. We further suggest that risk effects influence the spatial distribution of herbivory, rather than reduce overall herbivory that is expected if predators kill herbivores. Consequently, the relative importance of predation and risk effects is crucial for the way predators affect lower trophic levels.
Larvae of Cx.pipiens coocurred with Cladocera, but the latter established delayed in time. Biotope structure influenced time of species occurrence with ponds at reed-covered wetlands favouring crustacean development, while ponds at grassland biotopes favoured colonization by mosquito larvae. The mechanisms driving the negative effect of crustaceans on mosquito larvae were investigated within an experiment under artificial conditions. Crustacean communities were found to reduce both oviposition and larval development of Cx.pipiens. Crustacean communities of high taxa diversity, including both predatory and competing crustaceans, were more effective compared with crustacean communities dominated by single taxa. Presence of crustacean communities characterised by high taxa diversity increased the sensitivity of Cx.pipiens larvae towards Bti and prolonged the time of recolonization. In a final step the combined approach, using Bti and crustaceans, was evaluated under field conditions. The joint application of Bti and crustaceans was found to reduce mosquito larval populations over the whole observation period, while single application of Bti caused only short-term reduction of mosquito larvae. Single application of crustaceans had no significant effect, because high abundances of prior established mosquito larvae impeded propagation of crustaceans. At combined treatment, mosquito larvae were reduced by Bti application and hence crustaceans were able to proliferate without disturbance by interspecific competition. In conclusion, natural competitors were found to have a strong negative impact on mosquito larval populations. However, a time span of about 2 weeks has to be bridged, before crustacean communities reached a level sufficient for mosquito control. Results of a combined approach, complementing the short-term effect of the biological insecticide Bti with the long-term effect of crustaceans, were promising. Using natural competitors within an integrated control strategy could be an important tool for an effective, environmentally friendly and sustainable mosquito management.
Worldwide one third to one half of the freshwater crayfish species are threatened with population decline or extinction. Besides habitat deterioration, pollution, and other man-made environmental changes, invasive species and pathogens are major threats to the survival of European crayfish species. Freshwater crayfish are the largest freshwater invertebrates and strongly influence the structure of food webs. The disappearance of crayfish from a water body may change the food web and could have dramatic consequences for an ecosystem.rnOne goal in modern species conservation strategies is the conservation of genetic diversity, since genetic diversity is an advantage for the long-term survival of a species. The main aim of my thesis was to reveal the genetic structure and to identify genetic hotspots of the endangered noble crayfish (Astacus astacus) throughout Europe (part 1 of my thesis). Since the most significant threat to biodiversity of European crayfish species is the crayfish plague pathogen Aphanomyces astaci I studied new aspects in the distribution of A. astaci (part two of my thesis). The results serve as a basis for future conservation programs for freshwater crayfish. In the first part of my thesis I conducted a phylogeographic analysis of noble crayfish using mitochondrial DNA and nuclear microsatellite data. With these methods I aimed to identify its genetic hotspots and to reconstruct the recolonization history of central Europe by this species. I detected high genetic diversities in southestern Europe indicating that noble crayfish outlasted the cold climate phases during the Pleistocene in this region (Appendix 1). Because of the high genetic diversity found there, southeastern Europe is of particular importance for the conservation of noble crayfish. The mitochondrial DNA analysis points to a bifurcated colonization process from the eastern Black Sea basin to a) the North Sea and to b) the Baltic Sea basin (Appendix 2). A second independent refugium that was localized on the Western Balkans did not contribute to the colonization of central Europe. Furthermore, I found that the natural genetic structure is dissolved, probably due to the high human impact on the distribution of noble crayfish (e.g. artificial translocation). In the second part of this thesis using real-time PCR I identified calico crayfish (Orconectes immunis) as the fourth North American crayfish species to be carrier of the agent of the crayfish plague (Appendix 3). Furthermore I detected the crayfish plague pathogen in American spiny-cheek crayfish (Orconectes limosus) and native narrow-clawed crayfish (Astacus leptodactylus) in the lower Danube in Romania (Appendix 4). The distribution of infected spiny-cheek crayfish poses a threat to the native biodiversity in southeastern Europe and shows the high invasion potential of this crayfish species. Moreover, I found that even the native narrow-clawed crayfish in the Danube Delta, about 970 km downstream of the current invasion front of American crayfish, is a carrier of A. astaci (Appendix 5). This finding is of high importance, as the native species do not seem to suffer from the infection. In Appendix 6 I elucidate demonstrate that the absence of the crayfish plague agent is the most likely explanation for the coexistence of populations of European and American crayfish in central Europe. In my thesis I show that the common assumption that all North American crayfish are carrier of A. astaci and that all native crayfish species die when infected with A. astaci does not hold true. The studies presented in my thesis reveal new aspects that are crucial for native crayfish conservation: 1) The genetic diversity of noble crayfish is highest in southeastern Europe where noble crayfish outlasted the last glacial maximum in at least two different refugia. 2) Not all American crayfish populations are carrier of A. astaci and 3) not all Europen crayish populations die shortly after being infected with the crayfish plague pathogen.rnTo conserve native crayfish species and their (genetic) diversity in the long term, further introductions of American crayfish into European waters must be avoided. However, the introduction will only decrease if the commercial trade with non-indigenous crayfish species is prohibited.
Wild boars belong to the most wide spread ungulates in the world. They are characterized by a well performed adaption to their environment mainly due to their omnivorous dietary. The wild boar population in Germany increased during the past three decades. Nowadays their high density leads to problems in agricultural areas due to damage of crops and plays a significant role as disease vector as the classical swine fever. For an effective population management population size information is of crucial importance. Different traditional methods exist to estimate population sizes as direct sightnings, faecal drop counts or hunting harvest which provide only relative estimates and population trends. Absolute population sizes could be yielded by a Capture-Mark-Recapture (CMR) approach. However, capturing of wild boars is difficult to realize and costly in terms of personnel and field effort.
Furthermore the capture probabilities are heterogeneous due to the variable behaviour of individuals influenced by age, sex, and experience of the animals. Non-invasive genetic methods are a promising complement to the traditional methods for population size estimation particularly for wild boar. These methods reduce stress and capture bias and increase the number of re-captures. Faeces proved to be a suitable DNA source for wild boar genotyping, due to almost equal capture probability. However working with faeces implicates difficulties such as low DNA rnquality and quantity, genotyping errors as dropout and false alleles.
The main aim of the present study was to develop a reliable, cost-efficient, reproducible and practicable method for wild boar genotyping. This method should provide a reliable dataset of genotypes obtained from the collected faeces samples. Individual identification forms the basis for an improved mark-recapture approach. As there is no sound method for absolute population counts in free living wild boar, reference values for the validation of this new approach are missing. Therefore, different routines to reduce and to assess genotyping errors were compared within this thesis. For maximum amplification rate, the storage, the extraction methods and the PCR-procedure were optimised. A step by step procedure was evaluated in order to determine the minimum required microsatellite (MS) number for reliable individual identification including a test with family groups (female and embryo tissue) to distinguish even between close relatives. A multiple-tubes approach, post-amplification checking and different correction procedures were applied to reduce genotyping errors. In order to quantify real genotyping error rates (GER) of datasets derived from sampling in the Palatinate Forest in western Germany, different methods for GER determination were compared with each other, obtaining GERs between 0% and 57.5%. As a consequence, more strict criteria for the multi-tube approach and increased repetition number of homozygous samples were used. An additional method validation was the implementation of a blind test to achieve the reliability of the genotyping and error checking procedure. Finally a strict and practicable proposal for the lab procedure was developed, by beginning with faecal sample collection and ending with a reliable dataset with genotypes of each sample.
The results of the presented method were derived from two sampling periods in a 4000 ha area in the Palatinate Forest in Rhineland-Palatinate in December 2006 and 2007. Both provided high confidence intervals (CI) applying inaccurate estimates (eg. for 2006 population size amounted to 215 with CI 95% of 156-314 and for 2007 population size amounted to 415 with CI 95% of 318-561) due to low sampling sizes (for 2006 n = 141 and for 2007 n = 326), successfully analysed samples (for 2006 n = 89 and for 2007 n = 156) and recapture numbers (for 2006 n = 12 and for 2007 n = 24). Furthermore, the population estimates even for the lowest values were considerably higher than previously assumed by hunting statistics, which implicates an ineffective hunting regime in the study area. For the future prospect, to obtain more precise population size estimations the increase of sampling sizes is inevitable, because absolute and reliable estimates are highly desirable for wildlife management and the control of diseases transmission. Nevertheless, the method for individual genotyping of wild boars evaluated in this thesis could be successfully established resulting in reliable datasets for population estimation modelling with sufficiently low GER.
Population genetic structure in European Hyalodaphnia species: Monopolization versus gene flow
(2012)
Cyclic parthenogens displays an alternation of asexual and sexual reproduction which has consequences for the genetic structure of these organisms. The clonal diversity of cyclic parthenogenetic zooplankton populations is influenced by the size of the dormant egg bank, i.e., the amount of sexually produced dormant eggs that assembled in the sediment, as these dormant eggs contribute new genetic variants to the populations. Further, the clonal diversity is impacted by clonal erosion over time, which reduces the number of different clones through stochastic and selective processes. Although freshwater invertebrates are good dispersers through their dormant stages, the influence of gene flow is assumed to be negligible, as the local population successfully monopolizes the available resources. As these populations reach carrying capacity fast due to the asexual reproduction, the first colonizing individuals are able to successfully establish in the habitat, resulting in a priority effect which hinders the invasion of new genotypes. Due to clonal selection and sexual reproduction a population will locally adapt over time and will establish a dormant egg bank which facilitates the fast re-colonization after a hostile period. This thesis evaluates the processes altering the population genetic structure of cyclic parthenogenetic zooplankton with a special focus on the concepts of monopolization as well as the counteracting effects of gene flow, using large-lake Daphnia species. Thirty-two variable microsatellite DNA markers were developed and a subset of twelve markers was evaluated regarding their suitability for species assignment and hybrid class detection. With this marker set and an additional mitochondrial DNA marker forty-four natural European populations of the species D. cucullata, D. galeata and D. longispina were studied. In D. galeata, most populations were characterized by low clonal diversities which suggest high influence from clonal erosion over the growing season and a low contribution from the dormant egg bank. Further, recent expansions as well as gene flow were detected, probably caused by the anthropogenic alteration of freshwater habitats, in particular eutrophication of many European lakes. D. longispina and D. cucullata revealed a different genetic structure compared to D. galeata, with high genetic differentiation among populations. This indicates low levels of effective gene flow which is in line with the predictions of monopolization. Further, high clonal diversities were found in populations of the two taxa, suggesting a high contribution from the dormant egg bank while clonal erosion was often not detectable. In D. longispina, mitochondrial data revealed an ancient expansion which was probably initiated by the formation of glacial lakes after the last ice age.
In addition, in D. longispina not only clonal diversity but also genetic diversity was high, indicating that during the build-up of the studied populations the influence from gene flow was probably high. To better understand the processes that act on early populations the population build-up in regard to the temporal advantage of clones during invasion succession was experimentally studied and revealed that priority effects shape population structure of Daphnia species. However, in certain cases the highly superior clones resulted in the extinction of inferior clones independent of the temporal advantage the single clones had.
This clearly shows that not only the time of succession is important but also the competitive strength. rnIn conclusion, the results obtained show that the population genetic structure in cyclic parthenogenetic zooplankton species is impacted by various processes. In addition to earlier studies, which mainly focus on local adaptation, clonal erosion and the size of the dormant egg bank to understand population genetic structure, this thesis could show that gene flow may be effective as well. During population build-up the advantage of early arriving individuals does not necessarily predict the outcome of population assembly, as additional genotypes may contribute to the population. Finally, the genetic structure of established populations may be severely impacted by effective gene flow, if severe environmental changes alter the habitat of the locally adapted population.
To assess the effect of organic compounds on the aquatic environment, organisms are typically exposed to toxicant solutions and the adverse effects observed are linked to the concentration in the surrounding media. As compounds generally need to be taken up into the organism and distributed to the respective target sites for the induction of effects, the internal exposure is postulated to best represent the observed effects.
The aim of this work is to contribute to an improved effect assessment of organic compounds by describing experimental and modelling methods to obtain information on the internal exposure of contaminants in organisms.
Chapter 2 details a protocol for the determination of bioconcentration parameter for uptake (k1) and elimination (k2) of organic compounds in zebrafish (Danio rerio) eggs. This enables the simulation of the internal exposure in zebrafish eggs from an ambient exposure concentration over time. The accumulated contaminant amount in zebrafish eggs was also determined, using a biomimetic extraction method. Different bioconc-entration estimation models for the determination of internal steady-state concentrat-ion of pharmaceutical compounds in fish to an environmental exposure are presented in Chapter 3. Bioconcentration factors were estimated from the compounds octanol: water partition coefficient (KOW) to determine the internal exposure to an ambient concentration.
To assess the integral bioavailable fraction from the water and sediment phase of environmental contaminants for rooted aquatic plants, the internal exposure in river-living Myriophyllum aquaticum plants were determined over time, presented in Chapter 4. The plants were collected at different time points, with the accumulated organic contaminants determined using a liquid extraction method.
In Chapter 5 a protocol was established to enable the non-invasive observation of effects in M. aquaticum plants exposed to contaminated sediments over time. Since the toxicant effects are a result of all uptake and distribution processes to the target site and the toxico-dynamic process leading to an observed effect during static exposure, information on the internal exposure could thus be gained from the temporal effect expression.rn
Nandi forests (South and North Nandi forests) are situated in the Rift Valley Province of Kenya very close to Kakamega forest. From previous documents it has been seen that Kakamega and Nandi forests were connected to each other forming one big "U" shaped forest block till the beginnings of 1900s. Due to human pressures, currently there are three different forests form the previous one block forest. Although they were one forest, information on Nandi forests is very scanty when it is compared to that of Kakamega forest. The species composition and diversity as well as plant communities and population structure of Nandi forests have not been studied. Information is not available about the similarity status of South and North Nandi forests. Furthermore the natural regeneration potential (seedling bank) of these forests is not well studied and documented. Hence this study aims to fill these gaps.
In this study totally 76 quadrates (49 from South Nandi and 27 from North Nandi) were used to collect data. In the South Nandi forests 27 of the quadrates were laid in the better side of the forest (at Kobujoi) and the remaining 22 were in the heavily disturbed part of this forest (Bonjoge). The quadrates were arranged on transects that have one to one and half km which were parallel to the slope. The distance between the quadrates was 100 meter and transects are 500 m apart. The size of the main quadrate was 400 m2 (20 X 20 m) which also had five small plots (3 X 3 m) distributed on the four corners and in the center. Each woody plants (climbers, shrubs and trees) having more than one meter and greater than two centimeter diameter at breast height (dbh) were measured and recorded. Seedlings and herbaceous plants were sampled in the smaller plots. Individual plants were identified at species level and when it was not possible to identify in the field voucher specimen were prepared and latter identified at the East African Herbarium, National Museum of Kenya, and Nairobi. Clustering and ordination were performed using PC-ORD and CANOCO ecological softwares, respectively. For both clustering and ordination abundance data of the species was used. Shannon diversity index and evenness were computed using PC-ORD while similarity indices, Fisher alpha, rarefaction, species richness estimation (nonparametric species richness estimators) were conducted using EstimateS. Indicator species analysis was undertaken using PC-ORD. Basal area and height class distribution at forests level or site level (Bonjoge and Kobujoi) and diameter (dbh) class distribution for selected trees species were performed to evaluate population structure.
Furthermore importance value (IV) of woody plant species was calculated. SPSS version 16 was used to undertake both parametric (when data assume normal distribution) and nonparametric (when data are not assuming normal distribution) comparison of means, correlation and regression analysis.
In this study totally 321 vascular plant species comprising 92 families and 243 genera were identified in Nandi forests (both South and North Nandi forests). In South Nandi forest 253 plant species form 82 families and 201 genera were recorded while in North Nandi 181 species comprising 67 families and 155 genera were recorded. Jackknife second order estimators gave the highest species richness estimate for both South and North Nandi forests i.e. 284 and 209, respectively. In the case of highly disturbed and less disturbed parts of South Nandi forest 138 and 172 vascular plant species were recorded, respectively. Asteraceae, Rubiaceae and Euphorbiaceae are the top three species rich families of Nandi forests. In terms of different diversity measures (i.e. alpha and beta diversity, Fisher alpha, Shannon diversity and evenness indices) South Nandi is more diverse than North Nandi forest. Sörensen and Jaccard (classic) as well as their respective abundance based similarities showed that there is a low species similarity between South and Nandi forests. The cluster analysis resulted in three different plant communities and this result is supported by the ordination result.
South and North Nandi forest has inverted "J" height class distribution showing that larger proportion of woody plant individuals are found in the lower height classes. Similar pattern is observed when the diameters of all woody plants were considered together. However, different diameter class distributions (seven types) were identified when selected tree species were analyzed separately. It has been observed that the basal area of South Nandi forest is significantly lower than that of North Nandi forest (Mann-Whitney U =358, p < 0.001). Similarly Bonjoge has significantly lower basal area (t-value=3.77, p<0.01) than that of Kobujoi. Number of woody plat seedlings in South Nandi forest is significantly higher than that of North Nandi (Mann-Whitney U = 362.5, p<0.001). In the same way Bonjoge has significantly smaller number of ssedlings than Kobujoi (t-value 4.24, p<0.001). Most of species in both forests are able to resprout from stumps after physical damage; hence this helps the regeneration of the forests in addition to seedling banks. This study enables to fill some of the information gaps about Nandi forests especially of floristic composition, population structure, natural regeneration and human impacts on this ecosystem.
In dieser Studie sollte hinsichtlich der Entwicklung eines faunistisch begründeten Monitoringkonzeptes für hydrologische Interaktionen untersucht werden, inwieweit die Meiofauna in Hyporheal und Grundwasser in der Lage ist, Oberflächenwasser-Grundwasser-Interaktionen zu reflektieren und die hydrologischen Verhältnisse einer Uferfiltrationsanlage aufzuzeigen. Dafür wurden hydrochemische und faunistische Analysen bezüglich ihrer Aussagekraft miteinander verglichen. Außerdem wurde die Anwendbarkeit des Grundwasser-Fauna-Index (GFI) zur Beurteilung der Stärke des Oberflächenwassereinflusses auf unterirdisches Wasser überprüft. Für die Untersuchung wurde die Uferfiltrationsanlage Flehe der Stadtwerke Düsseldorf ausgewählt, auf deren Gelände 70 vertikale Entnahmebrunnen über eine Strecke von 1,4 km eine Brunnengalerie bilden, die im Jahr insgesamt 11 Mio. m3 Wasser fördert. Am Untersuchungsstandort wurden insgesamt 15 Observationspegel von Februar 2005 bis Januar 2006 faunistisch und hydrochemisch beprobt. Die physikochemische Untersuchung ergab eine Aufteilung des Untersuchungsgebietes in vier Zonen. Neben dem Oberflächenwasser des Rheins [OW Rhein] konnten das Uferfiltrationswasser zwischen Rhein und den Entnahmebrunnen [Hyporheal], alluviales Grundwasser hinter der Brunnengalerie [Alluv. GW] und bei größerer Entfernung zum Rhein landseitiges Grundwasser [landseitiges GW] differenziert werden. Dabei wies der Rhein die typische Charakteristik eines Fließgewässers auf, gekennzeichnet durch eine große Temperaturamplitude mit einem Sommermaximum, hohen Sauerstoffkonzentrationen mit einem Wintermaximum und erhöhten AOX-, DOC- und SAK254nm-Werten. Am Uferfiltrat der Gruppe [Hyporheal] wurde die Wirksamkeit der mikrobiellen Abbauprozesse während der Uferfiltration mit deutlichen Reduzierungen der DOC- und SAK- und Sauerstoffkonzentrationen ersichtlich. Die Gruppe [Alluv. GW] und verstärkt das [landseitige GW] waren durch eine höhere elektrische Leitfähigkeit und erhöhten Bor- und Sulfatkonzentrationen sowie z. T. geringen Sauerstoffgehalten gekennzeichnet. Anhand dieser hydrochemischen Differenzen konnte die unterschiedliche Herkunft des Wassers im Untersuchungsgebiet ermittelt werden Die faunistischen Untersuchungen zeigten ein differenzierteres Bild von den hydrologischen Verhältnissen als die Hydrochemie. Insgesamt konnten fünf ökologische Gruppen ermittelt werden. Die Gruppe [Hyporheal 1] der A-Pegelreihe wies als einzige euryöke Arten auf, die einen stärkeren Oberflächenwassereinfluss anzeigten. Im [Hyporheal 2] der B-Pegelreihe konnte eine artenreiche ökotonale Fauna nachgewiesen werden, während die Proben des alluvialen Grundwassers der C-Pegelreihe [Alluv. GW (Pumpe)] den Einfluss der Entnahmebrunnen reflektierten. In den Pegeln des alluvialen Grundwassers [Alluv. GW] wurde aufgrund der geringeren Beeinflussung der Pumpen artenreichere Zoozönosen vorgefunden. Das [landseitige GW] wies schließlich eine arten- und abundanzarme Fauna auf, die charakteristisch ist für Grundwasser mit geringem Oberflächenwassereinfluss. Folglich konnte die Fauna nicht nur die Herkunft des Grundwassers anzeigen, sondern auch den Einfluss und die Intensität des Oberflächenwassers auf das Grundwasser sowie anthropogene Störungen wie eine verstärkte Kolmation bzw. die Effekte der Wasserentnahme durch die Brunnen. Die Meiofauna im Grundwasserleiter der Uferfiltrationsanlage dürfte somit als Indikator für hydrologische Verhältnisse gut geeignet sein. Der Grundwasser-Fauna-Index konnte als der wichtigste Faktor aller physikochemischen Parameter ermittelt werden, der die faunistischen Gruppen am stärksten beeinflusst. Außerdem war der GFI in der Lage, die Auswirkung und Intensität des Einflusses von Oberflächenwasser auf die einzelnen Probestandorte anzuzeigen. Die hier dargestellten Ergebnisse zeigen, dass die Grundwasserfauna und der GFI viel versprechende Methoden zur Bewertung der hydrologischen Verhältnisse, insbesondere des Einflusses von Oberflächenwasser auf das Grundwasser sind. Daher sind sie als Ergänzung zur hydrochemischen Analyse zu empfehlen und können auch einen wichtigen Beitrag für die Vulnerabilitätsabschätzung leisten.
The genus Cheilolejeunea (Spruce) Schiffn. (Lejeuneaceae, Jungermanniopsida) is represented by 23 species in continental tropical Africa. The morphological characters such as features of the stem, leaf, lobule and perianth traditionally used to separate the taxa at both species and generic level have been found to be unstable. The species are variably ranked in several subgenera including Cheilolejeunea (Spruce) Schiffn., Euosmolejeunea Schiffn., Strepsilejeunea (Spruce) Schiffn. and Xenolejeunea Kachroo & Schust. Although the genus has never been monographed, there are a few regional taxonomic accounts for America, Australia and China. A comprehensive revision of Cheilolejeunea species is lacking in Africa where the existing studies are based on single subgenus and sub-regional flora or checklist compilations, which are sometimes without identification keys. This study revises the taxonomy of Cheilolejeunea and the closely allied genus Leucolejeunea A. Evans, in continental Africa based on morphological data analysed using phenetic and phylogenetic methods.
Foliicolous lichens are one of the most abundant epiphytes in tropical rainforests and one of the few groups of organisms that characterize these forests. Tropical rainforests are increasingly affected by anthropogenic disturbance resulting in forest destruction and degradation. However, not much is known on the effects of anthropogenic disturbance on the diversity of foliicolous lichens. Understanding such effects is crucial for the development of appropriate measures for the conservation of such organisms. In this study, foliicolous lichens diversity was investigated in three tropical rainforests in East Africa. Godere Forest in Southwest Ethiopia is a transitional rainforest with a mixture of Afromontane and Guineo-Congolian species. The forest is secondary and has been affected by shifting cultivation, semi-forest coffee management and commercial coffee plantation. Budongo Forest in West Uganda is a Guineo-Congolian rainforest consisting of primary and secondary forests. Kakamega Forest in western Kenya is a transitional rainforest with a mixture of Guineo-Congolian and Afromontane species. The forest is a mosaic of near-primary forest, secondary forests of different seral stages, grasslands, plantations, and natural glades.
Von November 2001 bis Dezember 2002 wurden 304 Grundwassermessstellen in Baden-Württemberg je zweimal faunistisch beprobt. Ebenso wurden Wasserproben zur Ermittlung der hydrochemischen Feldparameter entnommen. Dabei wurden 106 Tierarten gefunden, von denen 74 als stygophil oder stygobiont einzustufen sind. Mehr als 20 % der Messstellen waren unbesiedelt. Es wurden im Durchschnitt 2,3 Arten je Messstelle gefunden. Die meisten dieser Arten waren über das gesamte Gebiet verbreitet, nur etwa 20 waren in ihrer Verbreitung regional beschränkt. Vier Arten konnten nicht bestimmt werden und dürfen als bisher unbeschrieben gelten. Bemerkenswert ist der Einzelfund eines Syncariden der Familie Parabathynellidae, bei dem es sich um den Erstnachweis für diese Familie nördlich der Alpen und um eine neue, sehr ursprüngliche Art handelt. Mit zunehmender Tiefe wurde eine Abnahme der Artenzahl, Abundanz, Diversität und Besiedlungsfrequenz festgestellt, wobei diese Veränderungen unterhalb 20 m Tiefe sprunghaft erfolgten, wobei das oberflächennahe Grundwasser am dichtesten und artenreichsten besiedelt war. Die Zahl der tatsächlich vorkommenden, insbesondere der seltenen Arten, konnte vermutlich nicht annähernd erfasst werden. Die Zahl der in einer beliebigen Landschaftseinheit festgestellten Arten korrelierte linear mit der Zahl der untersuchten Messstellen. Auch konnten einige aus anderen Untersuchungen in Baden-Württemberg bekannte Arten nicht wiedergefunden werden. Dies weist darauf hin, dass die Zahl der im Untersuchungsgebiet lebenden Arten stark unterschätzt wurde. Eine starke Unterschätzung der Artenvielfalt im Grundwasser wird deswegen auch für die überwiegende Mehrzahl anderer grundwasserfaunistischer Studien angenommen. Die faunistischen Unterschiede zwischen den einzelnen Messstellen waren erheblich, was auf die große Heterogenität des Lebensraumes Grundwasser zurückzuführen ist. Eine Auswertung der Daten auf der Ebene der Einzelmessstellen und selbst auf der Ebene der Naturräume führte daher zu keinem Ergebnis. Ebenso wenig konnten deshalb Referenzzoozönosen beschrieben werden. Auf der nächst höheren Auswertungsebene, der Ebene der Naturraumgruppen zeigte die Fauna Verteilungsmuster, die sehr gut die geographischen Verhältnisse widerspiegeln, d. h. die faunistischen Ähnlichkeiten zwischen den Naturraumgruppen entsprachen annähernd auch ihrer räumlichen Lage zueinander. Auf dieser Auswertungsebene ergaben sich auch indirekte Zusammenhänge zwischen der Artengemeinschaft und der Landnutzung, der Leiterstruktur und der Nährstoffverfügbarkeit Fast alle Arten, die eine regional beschränkte Verbreitung aufwiesen, kamen im Einzugsgebiet des Rheins vor, waren jedoch in der Regel selten. Nur eine Art, Acanthocyclops gmeineri, wurde exklusiv im Donaueinzugsgebiet, an einer einzelnen Messstelle, gefunden. Ebenso waren auf Gemeinschaftsebene einzugsgebietsbedingte Verbreitungsmuster zu erkennen. Ein Einfluss der ehemaligen, voreiszeitlichen Flussgebietszugehörigkeit auf die Fauna konnte im Gebiet des Hochrheins, des Schwarzwaldes und des voralpinen Moor- und Hügellandes festgestellt werden: Diese Regionen, die heute dem Rheingebiet angehören, waren im Pliozän noch dem Flusseinzugsgebiet der Donau zugeordnet. Eine Reihe von Arten hat in diesen Regionen und im heutigen Donaueinzugsgebiet, also den Donau-Iller-Lechplatten und der Schwäbischen Alb, ihren Verbreitungsschwerpunkt. Wie oben bereits erwähnt, konnten die meisten regional begrenzten Arten im Rheineinzugsgebiet angetroffen werden. Nur eine Art konnte exklusiv für das rezente Donauflussgebiet festgestellt werden. Dieses Muster dürfte damit in Zusammenhang stehen, dass weite Teile des pliozänen oberen Donaueinzugsgebietes an das rezente Rheinsystem angegliedert wurden. So lassen sich drei Gruppen von Grundwassertieren unterscheiden: Arten des pliozänen Rheins, Arten der pliozänen Donau und nacheiszeitliche Wiederbesiedler mit einer landesweiter Verbreitung. Zusammenhänge zwischen der glazialen Vereisung und der rezenten Besiedlung des Grundwassers konnten nur insofern gefunden werden, als die meisten Arten als nacheiszeitliche Wiederbesiedler im gesamten Gebiet auftreten. Nur indirekte Zusammenhänge konnten zwischen der Besiedlung und der Art bzw. dem Chemismus der verschiedenen Grundwasserlandschaften gefunden werden. Als entscheidender Faktor für die Besiedlung erwies sich die hydraulische Leitfähigkeit. Diese überlagerte alle anderen Einflussgrößen, wie naturräumliche Gliederung, Hydrogeologie und Hydrographie. Danach konnten vier Gruppen unterschieden werden, von denen drei " Geringleiter, Lockergesteinsleiter und Kluftleiter - eindeutig voneinander zur trennen waren, während der Karst teilweise starke faunistische Ähnlichkeit mit den Lockergesteinsleitern aufwies. Große Ähnlichkeiten wurden zwischen den verschiedenen Lockergesteinsleitern festgestellt, so dass sie auch unter ökologischen Gesichtspunkten als einheitliche Gruppe aufgefasst werden können. Kluftleiter und Geringleiter waren in ihrer Besiedlung wesentlich heterogener als Karst- und Lockergesteinleiter. Um die Grundwassergemeinschaften bestimmter Landschaftseinheiten zu charakterisieren, erscheint es erforderlich, alle vorhandenen Aquifertypen der untersuchten Einheiten zu erfassen. Dabei sollte der Fokus nicht nur auf den Lockergesteinsleitern, sondern vor allem auch auf den Kluft- und Geringleitern liegen. Zwischen der faunistischen Besiedlung und natürlichen chemischen Stoffen und Parametern - einschließlich des Sauerstoffs " wurden keine direkten, signifikanten Zusammenhänge festgestellt. Korrelationen ergaben sich dagegen mit dem Nahrungsangebot, insbesondere der Menge an Detritus und toten Kleintieren (Aas). Daher ist davon auszugehen, dass das Auftreten von Grundwasserorganismen vor allem durch das Nahrungsangebot und weniger durch den Wasserchemismus beeinflusst wird. Das Nahrungsangebot seinerseits ist eine direkte Folge des hydrologischen Austausches, d. h. der Beeinflussung des Grundwassers durch Oberflächenwasser. Zur zukünftigen ökologischen Klassifizierung von Grundwasserlebensräumen wird ein hierarchisches, dreistufiges System, beginnend bei den geographischen, hydrographischen und naturräumlichen Verhältnissen über den Typ des Grundwasserleiters bis zum hydrologischen Austausch der Einzelstandorte diskutiert. Mit dem hydrologischen Austausch als zusätzliches Gliederungskriterium können die trophischen Verhältnisse mitberücksichtigt werden, die die kleinräumige Verteilung der Arten bestimmen.
Due to their confinement to specific host plants or restricted habitat types, Auchenorrhyncha are suitable biological indicators to measure the quality of chalk grassland under different management practices for nature conservation. They can especially be used as a tool to assess the success of restoring chalk grassland on ex-arable land. One objective of this study was to identify the factors which most effectively conserve and enhance biological diversity of existing chalk grasslands or allow the creation of new areas of such species-rich grassland on ex-arable land. A second objective was to link Auchenorrhyncha communities to the different grassland communities occurring on chalk according to the NVC (National Vegetation Classification). Altogether 100 chalk grassland and arable reversion sites were sampled between 1998 and 2002. Some of the arable reversion sites had been under certain grazing or mowing regimes for up to ten years by 2002. Vegetation structure and composition were recorded, and Auchenorrhyncha were sampled three times during the summer of each year using a "vortis" suction sampler. Altogether 110 leafhopper species were recorded during the study. Two of the species, Kelisia occirrega and Psammotettix helvolus, although widespread within the area studied, had not previously been recognized as part of the British fauna. By displaying insect frequency and dominance as it is commonly done for vegetation communities, it was possible to classify preferential and differential species of distinct Auchenorrhyncha communities. The linking of the entomological data with vegetation communities defined by the NVC showed that different vegetation communities were reflected by distinct Auchenorrhyncha communities. Significant differences were observed down to the level of sub-communities. The data revealed a strong positive relationship between the diversity of leafhoppers species and the vegetation height. There was also a positive correlation between the species richness of Auchenorrhyncha and the diversity of plant species. In that context it is remarkable that there was no correlation between vegetation height and botanical diversity. There is a substantial decrease in Auchenorrhyncha species richness from unimproved grassland to improved grassland and arable reversion. The decline of typical chalk grassland and general dry grassland species is especially notable. Consequently, the number of stenotopic Auchenorrhyncha species which are confined to only a few habitat types, are drastically reduced with the improvement of chalk grassland. Improved grassland and arable reversion fields are almost exclusively inhabited by common habitat generalists. The decrease in typical chalk grassland plants due to improvement is mirrored in the decline of Auchenorrhyncha species, which rely monophagously or oligophagously on specific host plants. But even where suitable host plants re-colonize arable reversion sites quickly, there is a considerable delay before leafhoppers follow. That becomes especially obvious with polyphagous leafhoppers like Turrutus socialis or Mocydia crocea, which occur on improved grassland or arable reversion sites only in low frequency and abundance, despite wide appearance or even increased dominance of their host plants. These species can be considered as the most suitable indicators to measure success or failure of long term grassland restoration. A time period of ten years is not sufficient to restore species-rich invertebrate communities on grassland, even if the flora indicates an early success.
Das Grundwasser unterliegt zahlreichen Nutzungen, gleichzeitig ist es Lebensraum einer artenreichen, hoch angepaßten Fauna. Verunreinigungen des Grundwassers mit Kontaminationen unterschiedlichsten Ursprungs stellen eine wachsende Problematik dar. Für das Monitoring von Altlastflächen werden bisher überwiegend physiko-chemische Methoden eingesetzt. Als weitere Möglichkeit bietet sich ein grundwasserfaunistisch begründetes Monitoring an. Da Freilanduntersuchungen über das Auftreten und die Verteilung von Grundwasserfauna in Altlastflächen bisher fehlen, widmet sich die vorliegende Dissertation dieser Thematik. Ein grundsätzliches Problem grundwasserfaunistischer Untersuchungen ist das Fehlen standardisierter Sammelmethoden. Daher erwies es sich als notwendig, die für die Untersuchung der Altlastflächen optimale Sammelmethode zu identifizieren. Insoweit liefert ein vorangehender Methodenvergleich die Grundlage für das Altlasten-Projekt. Ziel des Methodenvergleichs war es herauszufinden, ob die in Kluftgrundwasserleitern im Vergleich mit Lockergesteinsleitern festgestellte Artenarmut und die meist niedrigen Abundanzen habitat- oder auch methodenbedingt sind. Unter Verwendung eines phreatobiologischen Netzsammlers, einer pneumatischen Kolbenhubpumpe (System NIEDERREITER) und eines Quellnetzes wurden im Naturraum Pfälzerwald 16 Grundwasser-meßstellen (je 8 in den Kluftaquiferen des Buntsandsteins und den sandig-kiesigen Aquiferen der Talauen) und 8 Quellen, sowie 4 Grundwassermeßstellen in der pfälzischen Rheinebene hydrochemisch und faunistisch beprobt. Die Grundwässer beider Naturräume unterschieden sich sowohl hydrochemisch wie auch in ihrer faunistischen Zusammensetzung signifikant voneinander. Aus methodischer Sicht zeigten alle Sammeltechniken, mit Ausnahme der Quellbeprobung, trotz gewisser Unterschiede, qualitativ vergleichbare Ergebnisse. Ziel des Hauptteils der Arbeit " dem Altlasten-Projekt " war die Gewinnung erster empirischer Daten über das Vorkommen und die Verteilung von Grundwasserfauna in Abhängigkeit von Altlasten. Des weiteren sollten über die Korrelation der Grundwasserfauna mit hydrochemischen Parametern und den Koloniezahlen erste Ansätze für eine bioindikative Eignung gefunden werden. Basierend auf den Ergebnissen des methodischen Teils wurden unter Verwendung des phreatobiologischen Netzsammlers fünf in der pfälzischen Rheinebene liegende Untersuchungsstandorte (sechs Einzelschäden), die Kontaminationen unterschiedlicher Art aufwiesen, untersucht. Dabei handelte es sich um drei militärische und zwei industrielle Altlasten sowie eine Hausmülldeponie. Insgesamt wurden 91 Meßstellen, die sich im Zustrom, direkt im Schaden sowie im Abstrom befanden, zweimalig beprobt. Trotz der ausgeprägten Heterogenität der untersuchten Altlaststandorte sowie geringer Arten- und Taxazahlen und Abundanzen weisen die Verteilungsmuster auf Sensitivitäten der Fauna gegenüber Grundwasserverunreinigungen hin. In bezug auf einzelne Schadstoffe (LCKW, PCE, AKW) deuten sich schadstoffspezifische Verteilungsmuster der Fauna an. Das abundanteste Taxon der Untersuchung - die Nematoda - traten an den LCKW / PCE- kontaminierten Standorten nur in geringsten Abundanzen auf, ebenso wie die Parastenocaridae (Crustacea). Oligochaeta und einzelne Cyclopoida-Arten (Crustacea) scheinen hingegen deutlich höhere Konzentrationen dieses Schadstoffs zu tolerieren. Eine gegensätzliche Faunenverteilung wurde an den AKW- kontaminierten Standorten beobachtet. Hier zeigten sich die Nematoda wesentlich toleranter als alle anderen Taxa, ebenso wie die Parastenocaridae. Hingegen traten die Oligochaeta und Cyclopoida oberhalb geringer Konzentrationen nur noch sporadisch auf. Die abundanteste Cyclopoida-Art der gesamten Untersuchung, Diacyclops languidoides, konnte in Anwesenheit von AKW nicht nachgewiesen werden.
Fate and effects of insecticides in vegetated agricultural drainage ditches and constructed wetlands
(2006)
Studies have shown that runoff and spray-drift are important sources of nonpoint-source pesticide pollution of surface waters. Owing to this, public concern over the presence of pesticides in surface and ground water has resulted in intensive scientific efforts to find economical, yet environmentally sound solutions to the problem. The primary objective of this research was to assess the effectiveness of vegetated aquatic systems in providing buffering between natural aquatic ecosystems and agricultural landscape following insecticide associated runoff and spray-drift events. The first set of studies were implemented using vegetated agricultural ditches, one in Mississippi, USA, using pyrethroids (bifenthrin, lambda-cyhalothrin) under simulated runoff conditions and the other in the Western Cape, South Africa using the organophosphate insecticide, azinphos-methyl (AZP), under natural runoff and spray-drift conditions. The second set of studies were implemented using constructed wetlands, one in the Western Cape using AZP under natural spray-drift conditions and the other in Mississippi, USA using the organophosphate MeP under simulated runoff conditions. Results from the Mississippi-ditch study indicated that ditch lengths of less than 300 m would be sufficient to mitigate bifenthrin and lambda-cyhalothrin. In addition, data from mass balance calculations determined that the ditch plants were the major sink (generally > 90%) and/or sorption site for the rapid dissipation of the above pyrethroids from the water column. Similarly, results from the ditch study in South Africa showed that a 180 m vegetated system was effective in mitigating AZP after natural spray drift and low flow runoff events. Analytical results from the first wetland study show that the vegetated wetland was more effective than the non-vegetated wetland in reducing loadings of MeP. Mass balance calculations indicated approximately 90% of MeP mass was associated with the plant compartment. Ninety-six hours after the contamination, a significant negative acute effect of contamination on abundances was found in 8 out of the 15 macroinvertebrate species in both wetland systems. Even with these toxic effects, the overall reaction of macroinvertebrates clearly demonstrated that the impact of MeP in the vegetated wetland was considerably lower than in the non-vegetated wetland. Results from the constructed wetland study in South Africa revealed that concentrations of AZP at the inlet of the 134 m wetland system were reduced by 90% at the outlet. Overall, results from all of the studies in this thesis indicate that the presence of the plant compartment was essential for the effective mitigation of insecticide contamination introduced after both simulated and natural runoff or spray-drift events. Finally, both the vegetated agricultural drainage ditch and vegetated constructed wetland systems studied would be effective in mitigating pesticide loadings introduced from either runoff or spray-drift, in turn lowering or eliminating potential pesticide associated toxic effects in receiving aquatic ecosystems. Data produced in this research provide important information to reduce insecticide risk in exposure assessment scenarios. It should be noted that incorporating these types of best management practices (BMPs) will decrease the risk of acute toxicity, but chronic exposure may still be an apparent overall risk.
The estimation of the potential risk of pesticide entries into streams - and therefore the potential risk for the ecosystems - is an important requirement for the planning of risk mitigation strategies. Especially on the landscape level the required event triggered sampling methods are conjuncted with considerable efforts with regard to input data, time and personnel. To circumvent these problems simulation models form a reasonable alternative. The aims of this work were (A) the development of a simulation tool for the estimation of pesticide entries into surface waters on the landscape level, and (B) the application of the simulator for an exposure- and risk-assessment as well as the assessment of negative effects of pesticides on aquatic communities. Section 1 - Exposure-, Risk- and Effects In sections 1.1 and 1.2 the simulation model was applied to a multitude of small and medium sized streams in an agricultural impacted study area around the city of Braunschweig, Germany. Section 1.3 gives an overview of the simulators field of application and the general system structure. Section 1.1 - Scenario based simulation of runoff-related pesticide entries into small streams on a landscape level (English publication, p. 27): In this paper we present a simulation tool for the simulation of pesticide entry from arable land into adjacent streams. We used the ratio of exposure to toxicity (REXTOX) model proposed by the OECD which was extended to calculate pesticide concentrations in adjacent streams. We simulated the pesticide entry on the landscape level at 737 sites in small streams situated in the central lowland of Germany. The most significant model parameters were the width of the no-application-zone and the degree of plant-interception. The simulation was carried out using eight different environmental scenarios, covering variation of the width of the no-application-zone, climate and seasonal scenarios. The highest in-stream concentrations were predicted at a scenario using no (0 m) buffer zone in conjunction with increased precipitation. According to the predicted concentrations, the risk for the aquatic communities was estimated based on standard toxicity tests and the application of a safety factor. Section 1.2 - Linking land use variables and invertebrate taxon richness in small and medium-sized agricultural streams on a landscape level (English publication, p. 50): In this study the average numbers of invertebrate species across an arable landscape in central Germany (surveys from 15 years in 90 streams at 202 sites) were assessed for their correlation with environmental factors such as stream width, land use (arable land, forest, pasture, settlement), soil type and agricultural derived stressors. The stress originating from arable land was estimated by the factor "risk of runoff", which was derived from a runoff-model (rainfall induced surface runoff). Multivariate analysis explained 39.9% of the variance in species number, revealing stream width as the most important factor (25.3%) followed by risk of runoff (9.7%). Section 1.3 - Informationssystem zur ökotoxikologischen Bewertung der Gewässergüte in Bezug auf Pflanzenschutzmitteleinträge aus der Landwirtschaft - Systemaufbau und Anwendungsmöglichkeiten (German publication, p. 61): Section 1.3 contains a short overview of the simulation tool, the field of application and some examples of use, covering the effects of the width of the buffer zone as well as the creation of risk maps on the landscape level. Section 2 - The simulation tool An important aspect for the employment of a simulation model in the context of risk assessment is the applicability in practice: the accessibility of the needed input data, the conversion of the mathematical model into a software application that can be run on any current personnel computer and also an appropriate end-user documentation of the system. Section 1.4 - Informationssystem zur ökotoxikologischen Bewertung der Gewässergüte in Bezug auf Pflanzenschutzmitteleinträge aus der Landwirtschaft - Simulationsmodell und Systemaufbau (German report, p. 67): In this section a general overview of the simulation model as well as the schematic system structure given. Section 1.5 - Benutzerhandbuch (German report, p. 71): The user manual contains details concerning the installation of the system, generation of the required input data and the general use of the system. Moreover it presents some application examples (what-if analyses). Section 1.6 - Technical documentation (German report, p. 104): The technical documentation describes internal structures and processes of the simulation system. Section 1.6 provides information regarding the required structure of input/output tables.
Quellen sind hochdiverse Lebensräume mit einer stark spezialisierten Fauna, wobei noch Lücken im Verständnis der besiedlungsrelevanten Faktoren für die aquatische Makrofauna bestehen, so dass die Arbeit einen klärenden Beitrag hinsichtlich anthropogener Veränderungen und ihrer Auswirkungen auf die Besied-lung leisten will. Basierend auf Daten von 334 Quellen aller Grundwasserlandschaften von Rheinland-Pfalz wurden die Quellen morphologisch und faunistisch bewertet. Außerdem wurden die Quellen des Landes morphologisch typisiert, Referenzquellen analysiert und ein Ansatz für die morphologische und faunistische Leitbildentwicklung gegeben. Außerdem wird ein selbst entwickeltes, kompaktes Kartier- und Bewertungsverfahren zur Quellstruktur vorgestellt, wo bislang noch ein Defizit bestand. Das Verfahren erfasst in einem Erfassungsbogen alle ökologisch bedeutsamen Strukturparameter und bewertet in einem 5-stufigen System. Quellen sind hochdiverse Lebensräume mit kleinen Populationen in isolierter Lage. Bei der Untersuchung der 310 Quellen wurden insgesamt 292 Arten bzw. höhere Taxa des Makrozoobenthos nachgewiesen. Es wurden 89 quellassoziierte Taxa gezählt, hiervon waren 24 krenobiont und 65 krenophil. Der Anteil der quellassoziierten Fauna an der Gesamtfauna lag bei über 30%. Es fanden sich 19 Erstnachweise für Rheinland-Pfalz, 9 besondere Nachweise (seltene Arten) und 19 Rote-Liste-Arten. Erstnachweise fanden sich in wenig bearbeiteten Dipterengruppen, vor allem den Psychodidae (13), Limoniidae (5) und ferner den Simu-liidae (1). Bei den Köcherfliegen wurden etliche seltene Arten gefunden, welche bisher in Rheinland-Pfalz kaum gefunden wurden. Häufigere krenobionte Taxa waren Crunoecia irrorata, Bythinella dunkeri, Niphar-gus sp., Pisidium personatum, Salamandra salamandra, Thaumalea sp., Agabus guttatus, Crenobia alpina, Oxycera sp. und Beraea maura. Die durchschnittliche Taxazahl pro Quelle betrug 11, die maximale 62 Taxa. Schüttung und Morphologie der Quellen waren von Naturraum und Grundwasserlandschaft abhängig, so schütteten etwa Buntsandsteinquellen ergiebiger und konstanter als Tonschieferquellen. Quellen spiegeln die Hydrologie ihrer Einzugsgebiete wider, so dass in verschiedenen hydrogeologischen Einheiten die chemischen Parameter differierten. In einzelnen Quellen schwankte die Hydrochemie jahreszeitlich aber nur gering. Der pH-Wert etwa war im Quellwasser versauerungsgefährdeter Gebiete niedrig (Hunsrück, Pfälzer-wald), der Nitratgehalt anthropogen bedingt hoch in intensiv landwirtschaftlich genutzten Räumen. Die morphologische Quelltypologie, welche sich in erster Linie auf gängige Quelltypen stützte, ergab in elf hydrogeologischen Quelltypenräumen vier Basisquelltypen und fünf geochemische Sondertypen. Die Wan-derquelle wurde neu hinzu genommen. Die landesweite Verteilung der Quelltypen ergab bei ungefassten Quellen 57 % Sicker-, 32 % Sturz-, 9 % Tümpel- und über 2 % Wanderquellen. Wanderquellen dürften aber noch öfter vorkommen. Relief und Substrateigenschaften waren entscheidende Faktoren für die Typologie, so dass etwa Sturzquellen vor allem im Buntsandstein häufig waren, während Sickerquellen im Tonschiefer des rheinischen Schiefergebirges dominierten. Es wurden 85 Strukturreferenzquellen als typische, naturnahe Beispiele für einzelne Quelltypenräume genannt. Etwa zwei Drittel aller Quellen waren strukturell beein-trächtigt bis stark geschädigt, 59 % gefasst. Fassungen, Verrohrungen und Betonverbau waren ökologisch besonders bedeutsam. In Regionen mit intensiver Landwirtschaft lagen generell die stärksten Schädigungen vor. Im Forst waren Quellen durch Nadelholzmonokulturen und in den Hochlagen pufferarmer Mittelgebirge durch Versauerung geschädigt. Hinsichtlich der Besiedlung ergaben sich Unterschiede zwischen den Naturräumen, beeinflusst durch die Faktoren Geologie, Hydrochemie, Schüttungsverhältnisse, Landnutzung im Einzugsgebiet sowie die Struk-turvielfalt an der Quelle. Strukturell unveränderte und unversauerte Quellen besaßen im Schnitt höhere Ta-xazahlen. Einzelne Faktoren mit Einfluss auf die Besiedlung wurden in ihrer Auswirkung getestet. In Quel-len ist die Versauerung grundsätzlich besiedlungsbeschränkend und überlagert strukturelle Faktoren. Bei niedrigen pH-Werten kommt es zu verminderten Taxazahlen, allerdings sind viele Quellorganismen offen-sichtlich an eine leichte Versauerung angepasst, da in sauren Quellen der Anteil der Quellfauna höher war. Außerdem ergab die Untersuchung, dass neue und intakte Fassungen weniger Taxa und Quelltaxa aufwiesen, während bei alten und verfallenen Fassungen oft eine hohe Quelltaxazahl vorlag, so dass diese als sekundär ökologisch wertvoll zu bezeichnen sind. Die Umfeldnutzung und die Größe des Quellbereichs sind ebenfalls wichtig, so dass Quellen in Laub- und Mischwald sowie in extensivem Grünland am besten besiedelt waren. Die stärksten statistischen Zusammenhänge mit der faunistischen Besiedlung ergaben sich bei den Bewer-tungsergebnissen des Strukturverfahrens, was zeigt, dass das Verfahren realistisch bewertet. Multivariate statistische Methoden dienten der Ermittlung von Besiedlungsfaktoren und der Leitbildentwick-lung. Es ergab sich eine unterschiedliche Besiedlung bei verschiedener Hydrogeologie und Hydrochemie sowie bei verschiedenen Quelltypen. Allerdings waren die Ergebnisse nicht eindeutig, so dass die Trennung der Quelltypen nur teilweise gelang und die Quelltypen von den Grundwasserlandschaften überlagert waren. Die Faunenunterschiede verschiedener Regionen waren größer als die einer Region, so dass morphologische Quelltypen faunistisch nur innerhalb einer hydrogeologischen Einheit von Bedeutung sind. Es wurden regionale faunistische Leitarten für vier Grundwasserlandschaften genannt, wobei sich auf wenige hochstete Quellarten beschränkt wurde. Die Arbeit zeigt, dass faunistisch orientierte Leitbilder nur unter Schwierigkeiten anzugeben sind und vollständige Typuszönosen für größere Gebiete grundsätzlich in Frage zu stellen sind. Sehr häufige grundsätzliche Leitarten für Quellen silikatischer Mittelgebirge in Rheinland-Pfalz sind Crunoecia irrorata und Bythinella dunkeri.
In the present study the flora and vegetation of Kakamega Forest, an East African rainforest in Western Kenya, was investigated. Kakamega Forest is highly degraded and fragmented and is an ideal model to study the anthropogenic influence on the forest inventory. The main focus was to analyse the influence of human impact on the vascular plant species composition. During five field phases in the years 2001 to 2004 a total of 19 study sites scattered over the whole forest including all fragments were investigated regarding forest structure, species composition and plant communities. The different forest sites were analysed by three different methods, phytosociological relevés, line-transect and with the variable-area transect method. The forest survey revealed about 400 taxa of vascular plant species, among them 112 trees, 62 shrubs, 58 climbers and 114 herbs. Several species are restricted to this forest in Kenya, but only one endemic species, the herb Commelina albiflora, could be discovered. About 15 species were recorded as new for Kenya and probably at least one species is new to science. Kakamega Forest is a unique mixture of Guineo-Congolian and Afromontane floral elements. About one half of the vascular plant species has its origin in the lowland forests of the Congo basin and one third originates from Afromontane habitats. The present study represents the first description of plant communities of Kakamega Forest. An analysis of different forest sites and plantations resulted in 17 different vegetation units. For the mature forest sites eleven plant communities were described. The young succession stage consists of two plant communities. Since the disturbance history and the age of the different plant communities could be estimated, their chronology was also described. An exception are the study sites within the plantations and afforested sites. The four defined vegetation units were not described as plant communities, because they are highly affected by man and do not belong to the natural succession of Kakamega Forest. Nevertheless, the regeneration potential of such forests was investigated. Due to the different succession stages the changing species composition along a disturbance gradient could be analysed. Most of Kakamega Forest consists of middle-aged secondary forest often surrounded by very young secondary forest. A true primary rainforest could not be found due the massive influence by over-exploitation. In all parts of the forest the anthropogenic influence could be observed. The forest develops towards a climax stage, but a 2 Abstract comparison with former surveys shows that the regeneration is much slower than expected. Human impact has to be avoided to allow the forest to develop into a primary-like rainforest. But several climax tree species might be missing anyway, because after the broad logging activities in the past there are not enough seed trees remaining. Species richness was highest in disturbed forest sites. A mixture of pioneer, climax and bushland species could be recorded there. Therefore, a high species richness is not a suitable indicator for forest quality. The proportion of climax species typical for Kakamega Forest would be a better measure. Compared to the main forest block the forest fragments do not lack in diversity as expected due to fragmentation processes. Instead, the only near primary forest could be recorded in Kisere, a northern fragment. The high amount of climax species and the more or less undisturbed forest structure is a result of the strict protection by the Kenya Wildlife Service and due to low logging activities. Differences in species composition between the studied forest sites are either a result of the different logging history or management regime rather than due to different edaphic or climatic conditions.