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Küstenüberflutungsmoore sind typische Elemente der vorpommerschen Boddenküste an der südlichen Ostsee. Es sind nur wenige Dezimeter oberhalb des Meeresspiegels liegende Bereiche, die natürlicherweise von Röhrichten eingenommen werden. Mit der menschlichen Nutzung konnten sich seit dem Mittelalter eigenständige Salzgrünlandformationen etablieren, deren Fortbestand an eine extensive landwirtschaftliche Bewirtschaftung gebunden ist. Die Arbeit hat den Einfluss der Beweidung auf die ökofaunistische Indikatorgruppe der Laufkäfer als Repräsentanten des Stratums Epedaphon untersucht. Dafür wurden in den Jahren 2001 bis 2005 mit Bodenfallen die Laufkäfergesellschaften sowie verschiedene abiotische und biotische Standortfaktoren im Bereich von Küstenüberflutungsmooren am Greifswalder Bodden, auf der Insel Ummanz und am Strelasund erfasst. Darüber hinaus wurden bis in das Jahr 1986 zurückreichende vergleichbare Untersuchungen zu Laufkäfergesellschaften verschiedener Habitate der Ostseeküste von Mecklenburg-Vorpommern und Schleswig-Holstein analysiert. Die Auswertung erfolgte mit Hilfe deskriptiver und mulivariater Statistik, ökofaunistischer Indizes und Korrelations-, Regressions- und Indikatorarten-Analysen. Der Datensatz umfasste insgesamt 310 Laufkäfergesellschaften mit 156.140 Individuen aus 211 Arten. Im Gesamtvergleich aller Küsten- und küstennahen Habitate der südlichen Ostsee differenzieren sich die Laufkäfergesellschaften nach den Standortfaktoren Höhenlage, Bodensubstrat und vertikale Vegetationsdichte. Im torfgeprägten mittleren Geolitoral der Küstenüberflutungsmoore sind die horizontale Vegetationsdichte und die Streuschichtausprägung von entscheidender Bedeutung. Beide werden stark durch die Beweidung modifiziert und beeinflussen weitere edaphische Parameter wie Bodenfeuchte und –salinität sowie Raumfülle, -widerstand und das Mikroklima. In Kombination mit der Trittwirkung der Weidetiere und dem gesteigerten Überflutungseinfluss aufgrund der verringerten Anzahl von Mikrohabitaten kommt es mit zunehmender Beweidung zur Abnahme der Artenzahlen, Fangsummen und Biomasse der Laufkäfer sowie zur Zunahme des Individuenanteils halophiler und halobionter Arten. Es wurden drei charakteristische Laufkäfergesellschaften des aktuell beweideten Salzbinsenrasens (Juncetum gerardii), des aufgelassenen Salzgrünlandes (J. gerardii, Oenantho lachenalii-Juncetum maritimi) und ungenutzter Brackwasserröhrichte (Scirpetum maritimi) mit den entsprechenden Laufkäfer-Indikatorarten ermittelt. Das extensiv beweidete Salzgrünland ist ein überregional wichtiger Lebensraum für die naturschutzfachlich bedeutsamen Laufkäferarten Carabus clatratus und Agonum monachum. Aufgrund des anthropogen forcierten Klimawandels könnten sich zukünftig Veränderungen in der Zusammensetzung der Laufkäfergesellschaften ergeben, beispielsweise ist im Untersuchungsgebiet eine Arealregression der Indikatorart Bembidion transparens zu erwarten. Die Arbeit gibt Empfehlungen zum Nutzungsregime innerhalb des Salzgrünlandes und zur Effizienzkontrolle der Beweidungsmaßnahmen anhand der Laufkäfer. Dies wird beispielhaft anhand eines langjährigen Monitorings im Renaturierungsgebiet der Karrendorfer Wiesen dargestellt.
This dissertation evaluates the effects of site conditions and livestock grazing on the vegetation of Azerbaijan’s winter pastures. We improved methods to estimate grazing intensity in vast rangelands and enhanced an approach to detect discontinuities in vegetation changes along environmental gradients. All analyses use field data from the semi-arid rangelands of Gobustan and Jeiranchel, at the foothills of the Greater Caucasus mountains. The data set comprises 313 vegetation relevés, each sized 100 m², based on a pre-stratification using topographical parameters. Additionally, we included data from farm transects and exclosure experiments. For each plot, selected site and soil variables were determined. VEGETATION AND SITE CONDITIONS: By means of cluster analysis, we derived 16 vegetation types with a total of 272 vascular plant species. Our vegetation classification, which is closely linked to site conditions, is an important groundwork for adapted rangeland management and monitoring. The study areas are dominated by semi-deserts with a high coverage of dwarf shrubs, and the mean number of vascular plant species was found to be about 28 per 100 m². According to ordination analysis (NMDS), species composition changes primarily along the altitudinal gradient, gradually proceeding from the Salsola nodulosa semi-deserts of the lowest parts (below 300 m a.s.l.) to the Salsola ericoides and Artemisia lerchiana semi-deserts of the upper regions (300–650 m a.s.l.). Soil salinity and carbonate concentration decrease as altitude increases. A second gradient reflects grazing intensity. One plant community that is typically found on intensively grazed sites in the vicinity of farmyards stands apart from the rest, which are subject to lower grazing and trampling pressures. A third factor that differentiates plant communities is the sand concentration of the soils. Additionally, communities that occur on steep slopes differ from communities that occur on level terrain. EXCLOSURE EXPERIMENTS: Exclosure experiments revealed that short-time abandonment of grazing leads to an increase in the number of annual species, in vegetation coverage, and in the heights of forbs and grasses. Clipping experiments indicated that the herbaceous species show hardly any compensatory growth in response to grazing. ESTIMATING GRAZING INTENSITY: A recurrent theoretical problem in rangeland research is the spatial modelling of grazing intensity around grazing hotspots like farms or watering places, the so called piospheres. In a widely used approach, grazing intensity is assumed to decrease in direct proportion to the distance from a hotspot. The resulting response patterns, which relate characteristics of the vegetation or site conditions to grazing intensity, are often nonlinear, and have been interpreted as indicating threshold changes or diff erent state-and-transitions along grazing gradients. However, we show that these ‘thresholds’ are usually geometrical artefacts. Taking into account the concentric structure of grazing hotspots, we suggest a new approach that approximates grazing intensity as the ratio of the total number of livestock kept at the farm to the distance between a given plot and the hotspot centre. Our approach is a simple yet significant improvement over current approaches because it enables us to merge or compare data from different sampling sites and because the approximation is in direct proportion to other grazing indicators like dung density or soil salinity. SPECIES TURNOVER PATTERNS: Combining our new grazing pressure model with species presence/absence data, we modelled vascular plant species responses, patterns of species richness and species turnover along grazing gradients on farm transects in Gobustan. The derived typical species response pattern along the finite grazing gradient is a sigmoid decrease. Species richness declines monotonically with increasing grazing intensity and thus conforms to generally acknowledged assumptions on the relationship between species richness and grazing pressure in semi-arid rangelands. Species turnover along the gradient was calculated using the slopes of species response curves. At first sight, the resulting pattern gives evidence for a discontinuous change. However, it ranges within the 95 % confidence interval of a null model based on assumptions of the individualistic continuum concept. Thus, species composition seems to change continuously along grazing gradients in Gobustan. This new null model approach can probably be adapted and applied to all ecological gradients and is useful for the validation of individualcontinuum or community concepts.
Against the background of post-socialist transition and nationwide economic growth in Azerbaijan this dissertation analyses the utilisation of rangeland resources by mobile pastoralists in Azerbaijan. The study was motivated by the initially scarce knowledge about pastoralism in Azerbaijan and concerns about declining pasture condition due to growing livestock numbers. The study was guided by three research objectives, which were addressed cumulatively in five publications. The first objective aims at analysing the development of pastoralism in the transition period in comparison to developments in the pastoral sectors of other post-socialist countries. Secondly, the study addresses socio-economic causes of inappropriate pasture management by pastoralists. Finally, in an application-oriented research process recommendations for improving the management of pastoral farms and pasture governance were developed in order to mitigate inappropriate pasture management. For addressing these objectives the study frames the management of rangelands as a complex natural resource management system, in which the environment, users, governance structures, and the socio-political context are closely linked. Within this framework, the study focused especially on pastoral farms using a farm economics approach and on pasture governance with employing institutional economic theories. Regarding the methodology, a case study approach in four study regions was chosen in order to deal with the ex-ante limited information about Azerbaijani pastoralism and the explanatory aim of research.