Die vorliegende Dissertation behandelt die Ökologie von Cnidium dubium (Schkuhr) Thell. (Sumpf-Brenndolde), Gratiola officinalis L. (Gottes-Gnadenkraut) und Juncus atratus Krocker (Schwarze Binse), drei gefährdeten Arten, die als sogenannte Stromtalpflanzen in Mitteleuropa in ihrem Vorkommen eng an die Flussauen gebunden sind. Die Arbeit basiert auf verschiedenen Simulationsexperimenten und Feldstudien in der Unteren Havelniederung, einem „Feuchtgebiet von internationaler Bedeutung“. Sie behandelt Themenkomplexe wie das Samenbankverhalten, die Samenkeimung, die Stickstofflimitierung, die Konkurrenzkraft, das Verhalten der Pflanzen nach einer Sommertrockenheit und nach einer Winter/Frühjahrsüberflutung. Ferner widmet sie sich der Populationsbiologie der Arten und dem Verhalten der Pflanzen nach besonderen Störungsereignissen wie Mahd, Herbivorie und der Sommerflut 2002. Der Leser erfährt, wie die Pflanzen in verschiedenen Lebensphasen auf die auentypische Umwelt reagieren und erhält umfassende Einblicke in physiologische Mechanismen, die der Anpassung an die typischen Bedingungen einer mitteleuropäischen Flussaue dienen. Eine Interpretation der Ergebnisse zeigt auf, welche der spezifischen Eigenschaften zur Gefährdung der drei Stromtalarten beitragen. Die Arbeit ist für den Arten-, Biotop- und Landschaftsschutz interessant. Darüber hinaus bietet sie zahlreiche Anknüpfungspunkte zur ökophysiologischen Grundlagenforschung. Die verstärkte Nutzung physiologischer Methoden bei der Klärung ökologischer Fragestellungen wird angeregt. / The thesis deals with the ecology of three endangered European river corridor angiosperms Cnidium dubium (Schkuhr) Thell., Gratiola officinalis L. und Juncus atratus Krocker. The study is based on different experimental approaches and field surveys in a wetland along the Lower Havel River, a designated German Ramsar-site (Wetland of International Importance). This involves the examination of aspects of seed bank dynamics, germination, nitrogen limitation, competitive ability, and the response of plants to summer drought and/or winter/spring flooding. The thesis continues with a detailed study of the population biology of the species at natural sites and the response of these plants to specific disturbances like mowing, herbivory and the severe summer flooding in 2002. The reader learns about the traits of the three plant species to tolerate the typical conditions their natural sites are exposed to in different phases of their life cycle. He gets a comprehensive look at physiological means by which plants can adapt to the prevailing conditions of European river lowlands. The interpretation of the results is used to reveal specific plant traits, which may contribute to the endangerment of the three river corridor plants. As such, this thesis is interesting for protection of species, biotopes and landscapes. Furthermore, it provides numerous close connections to fundamental research from an ecophysiological perspective. The increased use of physiological methods is recommended in order to be able to adequately resolve ecological problems.

This thesis seeks to explain how site-scale design decisions can assist retention of rare plant communities concentrated in and near settled areas. To do so it focuses on a specific species and development context. Explanations are sought through examination of case studies of landuse developments in proximity to retained Garry oak plant communities located in the perimeter of Victoria, British Columbia. In the study region, exponential declines in species populations, health, and diversity of rare Garry oak ecosystems have been largely attributed to impacts from land-use developments. Over the past century, land-use developments have transformed the floral, spatial, structural and functional characteristics of the settled landscape. Isolated islands of imperiled plant associations remain on protected bioreserves: for recruitment and connectivity, these rare fauna rely on private-land greenways. Architectural teams have the potential to influence the decision-making processes that create ecologically-vital greenspace on private land, thereby enhancing survival for declining plant communities. Case-study evidence for the importance of land-use decisions on diminishing Garry oak meadow is gathered through vegetation surveys conducted on Garry oak meadow in proximity to six architectural projects on Victoria's western edge. Observed changes in growth extensions are then categorized in relation to human activities associated with built form, and correlated with principles from Landscape Ecology. An ARC of design strategies, developed in primary research by K. D. Rothley is adapted for architectural use as follows: firstly, AREA of a plant community is kept free of encroachment by the orderly frame established around vegetation; secondly, RARE SPECIES and habitat are identified with borders or signage; thirdly, CONNECTIVITY between retained landscapes is secured by siting roads and buildings to minimize ecosystem fragmentation. To effectively communicate preexisting landscape ecology principles, grouped under the ARC of strategies, illustrations and key-word phrases are developed. These principles, when integrated into architectural teams' structural knowledge, extend the architects' perceived role beyond aesthetics and economic efficiency. Enhancing habitat value through retention or restoration of rare ecosystems at the margins of suburban development, becomes an additional realm of influence for professional teams designing the spatial configurations of peri-urban landscapes.

This thesis seeks to explain how site-scale design decisions can assist retention of rare plant communities concentrated in and near settled areas. To do so it focuses on a specific species and development context. Explanations are sought through examination of case studies of landuse developments in proximity to retained Garry oak plant communities located in the perimeter of Victoria, British Columbia. In the study region, exponential declines in species populations, health, and diversity of rare Garry oak ecosystems have been largely attributed to impacts from land-use developments. Over the past century, land-use developments have transformed the floral, spatial, structural and functional characteristics of the settled landscape. Isolated islands of imperiled plant associations remain on protected bioreserves: for recruitment and connectivity, these rare fauna rely on private-land greenways. Architectural teams have the potential to influence the decision-making processes that create ecologically-vital greenspace on private land, thereby enhancing survival for declining plant communities. Case-study evidence for the importance of land-use decisions on diminishing Garry oak meadow is gathered through vegetation surveys conducted on Garry oak meadow in proximity to six architectural projects on Victoria's western edge. Observed changes in growth extensions are then categorized in relation to human activities associated with built form, and correlated with principles from Landscape Ecology. An ARC of design strategies, developed in primary research by K. D. Rothley is adapted for architectural use as follows: firstly, AREA of a plant community is kept free of encroachment by the orderly frame established around vegetation; secondly, RARE SPECIES and habitat are identified with borders or signage; thirdly, CONNECTIVITY between retained landscapes is secured by siting roads and buildings to minimize ecosystem fragmentation. To effectively communicate preexisting landscape ecology principles, grouped under the ARC of strategies, illustrations and key-word phrases are developed. These principles, when integrated into architectural teams' structural knowledge, extend the architects' perceived role beyond aesthetics and economic efficiency. Enhancing habitat value through retention or restoration of rare ecosystems at the margins of suburban development, becomes an additional realm of influence for professional teams designing the spatial configurations of peri-urban landscapes. / Applied Science, Faculty of / Architecture and Landscape Architecture (SALA), School of / Graduate

No description available.

The project was initiated by Eastern Cape Parks (ECP) as a request for the construction of inventories of priority species and their population levels inside three nature reserves on the Eastern Cape Wild Coast, South Africa, and to develop a strategic management plan to manage these natural resources in each reserve. Thirty key species were identified by local communities in and around Dwesa-Cwebe, Silaka and Mkambati Nature Reserves through community workshops. For forested areas belt transects of 100 m x 6 m where used. The basal circumference of key tree species within the belt transect was measured as well as the height of saplings (height < 150 m). Tree species were categorized based on densities, size class distribution (SCD) curves and values, and spatial grain. For grassland areas straight transects of 200 m long were used, along which ten 3 m x 3 m quadrates were placed at 20 m intervals. Within each grassland transect the height of herbs or tuft diameter of grasses was recorded and percentage cover estimated. Grassland species were categorized based on density, SCD curves and percentage cover. All species were placed into harvesting categories based on analysed ecological data that was collected in the field. Category 1 species were very rare or not found in the reserve and it was recommended that species be conserved and monitored. Category 2 species had low densities in the reserve indicating declining populations and was suggested that these be monitored and not harvested. Category 3 species had high densities and have potential for harvesting with strict limitations. Category 4 species were most abundant with very high densities and can be harvested within management guidelines. These categories were grouped further using social and ecological data such as harvesting risk, frequency of collection, use value and number of uses. This highlighted which species have conservation priority within each category and a decision can be made as to how intense or limited extraction should be. By incorporating GIS the distribution of each species was looked at and harvesting and non-harvesting zones established to determine where species can be extracted. Monitoring plans must consider the quantity of plant material collected, fire regimes, optimal harvesting rates and harvesting zones, and be able to pick up changes in populations. Also, it is important that the community be involved in conserving and monitoring these species. Adaptive monitoring and management must be used to steer harvesting practices in the Wild Coast reserves. This allows for the development of harvesting practices through ‘learning by doing’, and the evolution of good questions to guide monitoring decisions

Oldenburgia grandis is a rare, long-lived woody paleoendemic of the Fynbos Biome of South Africa. Confined to quartzite outcrops, it has a small geographic range and narrow habitat specificity. O. grandis responds to its fire-prone environment by resprouting. Elasticity analysis of O. grandis reveals that growth and fecundity were traded off for persistence of adult, mature and sapling stages. Morphological adaptations such as a corky fire-resistant bark and the ability to resprout after fire are traits that O. grandis have evolved to persist in a frequently disturbed environment. Population growth rate for sites undisturbed by fire for a number of years (l = 1.01) and sites at various stages of recovery after fire (l = 1.00) were very similar. The highest variation in transition probabilities for all sites was seen in the persistence of the seedling stage and growth from seedling to sapling. Observed population structure and stable stage distribution determined by the matrix model show that sites recently undisturbed by fire had high abundances of the adult and sapling stages. A peak in sapling stages was seen for the stable stage distribution where similar peak in sapling numbers were seen for population structures of sites at various stages of recoveryafter fire. Favourable environmental conditions for the persistence of O. grandis populations include no fire with transition probabilities between the observed minimum and maximum and fire frequency at a 10 year interval where seedling protection from the fire is high and adult and mature mortalities during the fire are low. Stochastic environmental events that could put populations (particularly small populations) at an increased risk of extinction include high to moderate fire intensities where seedling protection from the fire is low and adult and mature mortalities are high as a result of the fire.

Arable plant species diversity has been on a decline, with many species dependent on arable land becoming threatened. At the same time, attempts at defining the drivers of arable plant diversity have proven difficult and results are often contradictory. Much of the available data come from surveys that are small-scale and with great variability in methodology, leading to difficulties comparing them. In this study, I have used survey data from Gotland to examine how arable plant diversity is influenced by management, field size, soil texture and standing crop. I found a negative trend of diversity with increasing field size, and a suggested effect of management and soil texture on the presence of red listed arable plants. This study also evaluates the use of small datasets when examining plant diversity, and the limitations associated with it. It shows that while a small dataset cannot be analysed to the extent a more comprehensive one can, it is possible to identify trends and patterns with it, which may inform further studies.