Revegetation is employed to mitigate the spread of mine tailings in the environment by ameliorating tailings with organics to promote plant cover. Revegetation has proven to be successful in establishing plant cover, but the long-term effects are largely unknown. A field study was conducted to evaluate the success of four artificially revegetated tailings from Manitoba by comparing plant cover and diversity. Central Manitoba, Flin Flon, and Thompson had moderate cover while cover was low in Lynn Lake. All four sites had low diversity and were composed of early-successional species. The results suggest that while current revegetation methods promote plant growth on tailings, it is currently difficult to determine if and how the vegetation will progress from a grass-legume community to a boreal forest. In addition, while various amounts of effort were invested into each site, the results indicate the degree of remediation does not affect overall success.

Revegetation is employed to mitigate the spread of mine tailings in the environment by ameliorating tailings with organics to promote plant cover. Revegetation has proven to be successful in establishing plant cover, but the long-term effects are largely unknown. A field study was conducted to evaluate the success of four artificially revegetated tailings from Manitoba by comparing plant cover and diversity. Central Manitoba, Flin Flon, and Thompson had moderate cover while cover was low in Lynn Lake. All four sites had low diversity and were composed of early-successional species. The results suggest that while current revegetation methods promote plant growth on tailings, it is currently difficult to determine if and how the vegetation will progress from a grass-legume community to a boreal forest. In addition, while various amounts of effort were invested into each site, the results indicate the degree of remediation does not affect overall success.

Thesis (M. Phil.)--University of Hong Kong, 1999. / Includes bibliographical references.

Thesis (M. Sc.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references (leaves 100-106). Also available via the World Wide Web.

Made available in DSpace on 2014-06-11T19:27:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-01-26Bitstream added on 2014-06-13T20:16:40Z : No. of bitstreams: 1 jandoti_d_me_botib.pdf: 755910 bytes, checksum: d3aaec5ee62c92fe2ef7571335380637 (MD5) / O presente estudo foi realizado em uma Floresta Estacional Semidecidual, localizada na Estação Ecológica do Caiuá, município de Diamante do Norte, Estado do Paraná, Brasil. Para o levantamento fitossociológico, em cada uma das parcelas demarcadas, foram amostrados todos os indivíduos com perímetro a altura do peito (PAP) igual ou superior a 15 cm, totalizando 1.200 indivíduos arbóreos distribuídos em 78 espécies, 64 gêneros e 31 famílias. As famílias de maior riqueza de espécies foram Leguminosae com 14 espécies, Meliaceae com nove, Myrtaceae, Rutaceae e Euphorbiaceae com cinco espécies cada, Lauraceae com quatro e Polygonaceae, Annonaceae e Flacuortiaceae com três espécies cada. Sloanea monosperma, Gallesia integrifolia, Guarea guidonea, Trichila casaretti, Nectandra sp., Chrysophyllum gonocarpum, Guarea kunthiana, Nectandra cuspidata, Campomanesia xanthocarpa e Endlicheria paniculata foram as espécies com maior valor de importância. O índice de diversidade de Shannon (H’) obtido foi de 3,37, corroborando com valores obtidos em outros estudos desenvolvidos em florestas ripárias no Noroeste do Paraná / This study was carried out in a Semi-deciduous Seasonal Forest located in the Estação Ecológica do Caiuá, city of Diamante do Norte, State of Paraná, Brazil. All plants with DBH greater than or equal to 15 cm were sampled within each parcel, totalizing 1,200 individuals distributed within 78 species, 64 genus and 31 families. Plant families with great species richness were Leguminosae with 14 species, Meliaceae with nine, Myrtaceae, Rutaceae and Euphorbiaceae with five species each, Lauraceae with four and Polygonaceae, Annonaceae and Flacuortiaceae with three species each. Sloanea monosperma, Gallesia integrifolia, Guarea guidonea, Trichila casaretti, Nectandra sp., Chrysophyllum gonocarpum, Guarea kunthiana, Nectandra cuspidata, Campomanesia xanthocarpa and Endlicheria paniculata were those species with high levels of importance. The Shannon’s diversity indices (H’) was 3.37, corroborating with other studies carried out in riparian forests in the Northwest region of Paraná

Thesis (M.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 37-43). Also available in electronic format on the Internet.

Thesis (doctoral)--Wageningen Universiteit, 2005. / "Propositions" inserted. Includes bibliographical references (p. 107-122).

No description available.

Thesis (MTech (Nature Conservation))--Cape Technikon, 2003. / The study was carried out on two adjacent farms on the plains of the Nama Karoo near Beaufort West. The impacts of three grazing treatments (a) zero grazing (b) non-selective grazing (c) conventional grazing, on plant diversity and certain vegetation parameters were compared. Unpredictable and variable rainfall and major disturbance events such as droughts drive vegetation change in the Nama Karoo. Major recruitment events are rare and can determine Karoo vegetation composition for many years. The diversity of plant species plays an important role in determining vegetation composition during major recruitment events and following drought or disturbance such as grazing. Grazing can influence the composition, abundance and seed production of Karoo plants and in so doing influence the future abundance of desirable and undesirable forage species. These changes may only become evident over long periods, but small changes in vegetation as a response to grazing treatment can accumulate considerably over time.On the farm Elandsfontein, studies have shown that non-selective grazing leads to a higher plant turnover rate, resulting in more vigorous and productive plants, and improved ecosystem functioning. However there is no evidence of this grazing system promoting or reducing plant diversity. The aim of this study was to test whether the non-selective grazing system promoted or reduced plant diversity compared to no grazing and conventional grazing. The hypothesis was that there were no differences between the grazing treatments in terms of plant diversity or any of the vegetation parameters measured. To evaluate this hypothesis, plant data were collected from the three grazing treatments using the Modified-Whittaker vegetation sampling method. The method was further modified for this study to allow for accurate abundance measurements rather than estimates, and an increased area for recording species richness. Using various diversity indices that incorporate species richness and the proportional abundance of species, plant diversity values for each treatment were obtained. No differences in terms of plant diversity were found between the treatments. A significant difference between treatments was found in the density of plants, particularly in perennial grasses and shrubs. Canopy cover percentage did not differ for individual species or as total cover between the treatments.

One goal central to ecology is to understand how species interactions and biophysical processes interact over vastly different scales to govern past, current, and future patterns of diversity. Today, this goal is particularly critical given the degree to which rapid environmental change is affecting species distributions and community composition. Natural environmental gradients provide excellent opportunities to uncover possible mechanistic links between species distributions and environmental conditions links that are invaluable for understanding how species may respond to environmental change. This dissertation builds on recent approaches that combine information on species' functional traits and evolutionary histories to refine our view of how contemporary and historical processes jointly govern the distribution of biodiversity. In the context of tropical tree communities of Puerto Rico, the following four chapters evaluate hypotheses about the distribution of different dimensions of diversity (i.e., species, functional, and phylogenetic) across regional abiotic gradients. In chapter 1, I develop an island-wide molecular phylogeny for the native and naturalized trees of Puerto Rico, and show preliminary evidence that dry forests comprise an evolutionarily clustered subset of the total island tree flora. In chapter 2, I examine functional and phylogenetic diversity across spatial resource gradients, and use these patterns to infer variation in community assembly processes along a gradient of water availability. In chapter 3, I use temporal shifts of functional and phylogenetic diversity during secondary succession to infer the shifts in the processes underlying successional change in wet forests of Puerto Rico. Finally, in chapter 4, I evaluate the linkages between species functional traits and their geographic distributions, and test the hypothesis that community-weighted mean trait values reflect the `optimal' strategy for a given set of abiotic conditions. A theme common to all chapters is the idea that functional and phylogenetic dimensions of diversity can shed light on the processes underlying patterns of diversity better than more traditional metrics of species diversity. I provide recommendations for future research directions at the end of each chapter and in the final conclusions.