Thesis (M.S.)--Southern Oregon University, 2005. / "A thesis submitted to the Department of Biology of Southern Oregon University in partial fulfillment of the requirements for the degree of Master of Science in Environmental Education." Includes bibliographical references (p. 36-50) Also available via Internet as PDF file through Southern Oregon Digital Archives: http://soda.sou.edu. Search Bioregion Collection.

Thesis (Ph.D.)--Ohio University, November, 2005. / Title from PDF t.p. Includes bibliographical references (p. 121-150)

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xvi, 263 p.; also includes graphics (some col.). Includes bibliographical references (p. 241-263). Available online via OhioLINK's ETD Center

The thesis explores various aspects of ecology of endangered damselfly Coenagrion ornatum, the specialists for lowland headwaters, in post-mining streams of Radovesicka spoil. The first part of thesis is manuscript which has been already submitted in Journal of Insect Conservation. In the first part, we focused on population estimate of the local population using capture-recapture method, and explored its habitat requirements across life stages and spatial scales. In the next part, I assess mobility of the focal species and reveals basic distribution patterns. Finally, the thesis suggest various implications for restoration of post-mining freshwaters and conservation of the studied species.

Magister Scientiae (Biodiversity and Conservation Biology) / Heavy grazing of rangelands in the succulent karoo has placed the biodiversity of these areas at risk. In Paulshoek, overgrazing has resulted in the removal of much of the palatable vegetation from low lying areas. The remaining vegetation is dominated by Galenia africana, an unpalatable shrub. Loss of favourable microsites, competition from Galenia africana, as well as loss of seed banks, may be the cause of poor seedling establishment of palatable species. I explored how high grazing pressure has changed this system by comparing with surrounding private farms, which have a history of less concentrated grazing pressure. I found that heavy grazing increased the seed bank of Galenia africana in the soil and reduced that of palatable perennials. Vegetation cover was significantly lower (p<0.0001) under heavy grazing and consisted mainly of Galenia africana and few palatable perennials. The aim of this study was to test techniques that could restore this area to a more productive palatable shrubland. I propose that rehabilitation can be used to gain an understanding of the ecological factors that may be sustaining this altered vegetation state. My methodology involved biophysical interventions to manipulate this system. Grazing pressure was removed from the study area and vegetation changes were monitored under grazed and protected regimes. No change in plant cover was found after two years. However, there was an increase in cover of palatable perennials in relation to overall cover. I physically manipulated the environment by introducing microcatchments and brushpacks to act as traps for water, seed and organic material. These interventions resulted in few changes, however, I found higher soil moisture levels in microcatchments and under brushpacks than open positions. Cover of ephemerals was also significantly higher (p<0.001) in areas that had been brushpacked. In the absence of a seedbank, I tested whether the introduction of seed would result in recruitment. Seed of four palatable perennial species was sown into open, packed and tilled soil. A low number of seeds germinated in the first year and most seedlings died. Further germination occurred after a rainfall event in the second year, but still in very low numbers. Various microhabitats were implemented to assess seedling establishment requirements. Seedlings were transplanted in microcatchments and open positions; in areas cleared of Galenia, under adult Galenia and brush packs and in bare soil. Microhabitats did not facilitate seedling establishment, and few seedlings survived. Survival of seedlings was influenced by the size of seedling at transplantation and site differences. I conclude that the factors underlying vegetation change are complex. Individual physical and biological interventions offered no immediate change in vegetation cover and composition. However, a combination of interventions may over time and under favourable climatic conditions allow the return of a viable palatable shrubland. / South Africa

It is an unresolved paradox that non-native species are successful in novel environments whereas native species, presumably adapted to that environment, decline. This knowledge gap has persisted because third party processes in invasion ecology have been overlooked. Ungulate densities are increasing due to the eradication of predators and landscape change and I asked how herbivory and invasion might interact to cause declines of native species. In Garry oak meadows, Canada’s most endangered ecosystem, native forbs have declined relative to non-native grasses and I tested the facilitatory role of herbivory in that degradation. My investigations, novel to the field, were conducted on islands spanning the Canada-US border. Islands served as natural experimental units in a mensurative study of abundance patterns in seven plant groups and 15 focal species along gradients of herbivory, biogeography, soil depth, and human activities. Increasing ungulate densities were related to declines in abundances of native forbs, and increasing abundances of non-native annual grasses. These regional patterns were upheld by two plot-based, 2x2 factorial experiments that contrasted the fitness of native species under manipulations of herbivory and competition for light. Specifically, I showed that ungulates limited the establishment, growth, survival and reproduction of seedlings and transplanted native forbs and shrubs and that competition from non-native species had little effect. I also calculated forage selectivity indices and tested the efficacy of fencing and cutting to reduce competition, for the restoration of native community biomass. Non-native annual grasses were rarely browsed and increased with increasing ungulate density. Non-native perennial grasses declined with herbivory, however, their regional abundances were unaffected by ungulate density despite being preferentially foraged. That non-native annual and perennial grasses differed in their responses to herbivory has consequences for restoration and illustrates the challenge of developing a comprehensive theory of invasion. Reducing ungulates, necessary for the recovery of native forbs, also benefits non-native perennial grasses and therefore their removal speed recovery of Garry oak meadows. Despite advances in invasion ecology, scientists and managers are disconnected and research is rarely implemented. I conclude by proposing seven solutions to facilitate the integration of science into management. / Forestry, Faculty of / Graduate

Ecological restoration that aims to reinstate indigenous processes may be constrained by regional and local conditions, especially those that drive dispersal and colonisation. Local conditions can be managed, while regional conditions cannot. The management of costly rehabilitation programmes is considered best practice when scientifically informed. My thesis documents the responses of biological communities to a range of local conditions developing in coastal dune habitats in response to ecological restoration. Here, landscape-level (spatial structure of patches of tree canopies) local conditions were distinguished from site-level (topography, soil nutrient content, woody plant community richness, microclimatic variables) local conditions. The spatial structure of tree canopies varied over time and differed between the mining lease site and the relatively undisturbed benchmark site prior to (1937- 1970), and after (1990-2006) mining. For example, approximately 20% of the mining lease site and 40% of the benchmark site was covered by tree canopies prior to mining. However, after mining and rehabilitation, the structure of tree canopies began to converge towards that of the benchmark. The topographic profile of coastal dunes was less heterogeneous after mining and rehabilitation than before. Aspect, elevation and gradient of dune slopes were also different and had shifted in space. Variability in the structure of tree canopies could not explain variability in species richness, forest-associated species richness and proportion of benchmark species for the millipede, dung beetle and bird communities ashad been expected. However, species composition did change (though idiosyncratically) with age-related changes in soil nutrient availability and tree species diversity. Temperature, relative humidity and light intensity varied with dune topography, but soil nutrient content (C: N ratio and pH) was better accounted for by the age of the regenerating forest than by dune topography. Similarly, analysis of covariance suggested that tree canopy density, woody plant richness and millipede species richness only responded to the aspect, elevation and gradient of restored coastal dunes when age was taken into account as a covariate. However, the response of keeled millipedes to dune topography, regardless of regeneration age, suggested that the microclimatic variability brought about by topographic heterogeneity may provide these specialists with suitable microhabitats. Throughout my thesis, the age of regenerating patches of indigenous canopies was often more important as an explanatory variable than habitat conditions per se. Age itself is not a determinant of biological communities, but merely the axis along which habitat conditions change with succession, and later, patch dynamics. Therefore, as elsewhere, my thesis has highlighted age as a useful proxy for the response of biological communities to local conditions. It seems that managing local variables such as those considered in my assessment is not an avenue through which to enhance restoration. After kick-starting initial conditions, best practice rehabilitation management should therefore focus on minimizing external disturbances rather than interfering with natural processes. / Thesis (PhD)--University of Pretoria, 2013. / Zoology and Entomology / unrestricted

No description available.

The goal of this project was to determine the effects of oyster reef restoration on oyster coverage, wave height dissipation and seagrass recruitment. First, to assess the current versus historical coverage of natural, dead and restored oyster reefs within Mosquito Lagoon, aerial photographs from 2009, provided by Saint Johns River Water Management District, were digitized using ArcGIS software. Live reefs, restored reefs and dead reefs were screen digitized using a reef ‘signature’ in order to estimate the area of each type of reef. The 2009 maps were used as a guide to digitizing the historical aerial photographs (1943, 1951, 1967, 1971, 1984, 1995, 2006). Dead reefs increased both in number and aerial extent during the study period (1943 – 2009), with 2009 having over 10 acres of dead reef coverage. Dead reefs were more likely to be found along major boating channels. Several dead reefs exhibited migration into the mangrove islands located landward of the 1943 footprint, with some dead reefs completely washing up into the shoreline. Restoration of dead reefs added 0.5 acres of live oysters to the Mosquito Lagoon area as of January 2009. Second, I examined how different oyster reef types (natural reef, restored reef, dead reef) reduced wave height. To determine wave height attenuation on each reef type, experiments were conducted in a 9 meter long wave tank using sensors that measured changes in wave height. For each reef type, replicate reefs were created in the wave tank. Shoreline sediment without oysters was used as a control. Using the wave generator, wave heights similar to Mosquito Lagoon boat wakes were created. Restored reefs reduced the incoming wave height by 25% compared to sediment without oysters. iii Lastly, I examined the potential link between oyster reef restoration and recruitment of seagrass fragments. Monthly surveys were performed to quantify the number of seagrass fragments encountering the three oyster reef types: dead reefs, natural reefs and restored reefs. The quantity of seagrass fragments was found to be similar on the three different reef types, but did show a significant trend of seasonality, which corresponds with the growing season of Halodule wrightii. Next, I tested retention of experimentally manipulated seagrass fragments on five natural and five restored reefs. Restored reefs retained seagrass fragments for significantly longer than natural reefs. I also measured seagrass fragment entanglement on each reef type inside the wave tank. I found that seagrass fragments were significantly more likely to become entangled and retained on restored reefs compared to dead and natural reefs. Overall, these metrics are important for determining the success of long-term oyster restoration project in Mosquito Lagoon, Florida. This project has found that oyster restoration is increasing the area of oyster habitat as well as providing important ecosystem services.

No description available.