Thesis (M.F.A.)--Ohio State University, 2006. / Includes bibliographical references (leaves 122-128). Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--University of Florida, 1982. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 249-265).

No description available.

No description available.

Thesis (M.S. in landscape architecture)--Washington State University. / Includes bibliographical references.

This thesis is involved with changes that have occurred to small mammal populations following a major disturbance in the Anglesea region as a result of the 1983 Ash Wednesday fires. Fire, with its effects on spatial and temporal heterogeneity, was found to be an important factor in the maintenance of vegetation and small mammal community structure and diversity in the region. Successional changes in vegetation and small mammal communities were described by multivariate analyses, using data collected annually from 22 study sites. The use of factor analysis techniques, in reducing the annual capture data content, enabled long-term changes in the structure of mammal communities to be interpreted. The small mammal communities in the coastal heath and forest vegetation in the Anglesea region show evidence of a general resilience, (the degree and speed of recovery), to disturbance. Two phases of successional response to fire by mammal species have been proposed; a ‘re-establishment’ phase which occurs in the initial 5-6 years post-fire and is accompanied by rapid increase in species’ abundance, and a subsequent ‘maintenance’ phase accompanied by relatively minor changes in abundance. Habitat Suitability Indices were produced relating to these phases. Vertical density measures of understorey shrubs and herb layers showed significant relationships with small mammal species abundance at the study sites. Long term studies following major disturbances are needed to distinguish between short term recovery of plant and animal species and long term changes in these species. Studies extending over a number of years enable a better directional view of changes in small mammal communities than can be determined from . observations made over a short period. As a part of the investigation into temporal change, it was proposed to undertake trial reintroductions of the Swamp antechinus, Ant echinus minimus, a marsupial dasyurid species which was trapped in the area prior to the 1983 fire, but rarely subsequently. Other more commonly observed native small mammal species (e.g. Rattus fuscipes,R. lutreolus, Antechinus stuartii, Sminthopsis leucopus) had re-invaded the proposed reintroduction site after this fire. Failure of A. minimus to re-establish may have been due to spatial separation of the pre-fire populations coupled with the extensive area burnt in 1983, A source population of the species was located about 100km to the west and habitat utilization and interspecific and niche relationships between the species making the small mammal community explored. Discriminant analysis revealed some spatial separation of species within a habitat based on structural vegetation factors rather than floristic factors. Temporal separation of species was observed, asA. minimus were more active than Rattus species during daylight periods. There was evidence of micro-habitat selection by species, and structural vegetation factors were most commonly identified in statistical analyses as contributing towards selection by small mammal species. Following a theoretical modelling study three reintroduction trials were carried out near Anglesea during 1992-94. Individuals were subsequently radio tracked, and habitat relationships between the species in the small mammal community investigated. Although successful breeding of A, minimus occurred during the latter two trials, the subsequent fate of offspring was not determined. Invasive techniques required to adequately monitor young animals were considered potentially too damaging. Telemetry studies indicated a preference of A. minimus for short, wet heath vegetation. Structural vegetation factors were identified as being significant in discriminating between capture locations of species. Small scale and inexpensive trial reintroductions have yielded valuable additional data on this species and may be viewed as a useful tool in the conservation of other small native mammals.

This thesis set out to investigate the influence of disturbance on the succession of the Krakatau islands (Rakata, Sertung, Panjang). The hierarchical model of succession by S. Pickett and colleagues (1987) was adopted as a research framework, and provided the basis for an alternative model of succession on Krakatau that focuses on processes rather than successional pathways. Investigations were conducted on (i) the meso-scale, and (ii) the patch-scale, (i) quantified the recent disturbance regime, and inter- and intra-island differences in diversity, (ii) compared sapling performance (growth, mortality and recruitment), and species compositional patterning in space and time for saplings and the seed bank with respect to island, gap size and severity of disturbance. Multivariate techniques were used, and amongst other attempts at characterising the light environment, hemispherical photography was employed. For the first time the effect of a continuous period of volcanic activity (1992-1995) of Anak Krakatau could be directly quantified and compared between Panjang and Sertung (ash-affected) and Rakata (receiving no ash). Increased rates of gap formation in the volcanically active period in comparison to the previous decade were found for all islands. This supports the disturbance-driven model of Whittaker and colleagues. However, an extension is required, because, contrary to expectation, Rakata also experienced more disturbance. This increase is argued to be a result of more severe weather conditions, and an increased number of earth tremors, during times of volcanic activity. The disturbance factors of extreme climatic events (e.g. ENSO events) and human impact are also proposed for inclusion in the alternative model. Drought associated with the 1994 El Niño is of relevance to short-term and potential long-term impact on regeneration dynamics and succession. Attention was drawn to the local human influence of pumice mining on the coastal forests. Supporting previous findings on the plot- and whole island scales, data from species presence/absence transects established that species richness and beta-diversity on the ash- affected islands was also lower on the meso-scale. Panjang's canopy composition is less uniform, and locally more species-rich than Sertung's. More evidence of the suggested decline of the mono-dominant species Neonauclea calycina and Timonius compressicaulis was gathered. The third dominant, Dysoxylum gaudichaudianum, is expanding in the lowlands of all islands. This is aided by its ability to regenerate in moderate shade, to grow rapidly in gap environments, and its tolerance of ash-fall, drought and herbivory. However, on Rakata, it is not expected to become generally mono-dominant because a considerable number of other potential canopy species are present. Sapling performance and species composition and its changes were in general strongly affected by ash-fall and drought. These factors tended to override effects of gap size and severity of disturbance. Advance regeneration, and the composition of the local forest type were identified as important factors influencing the composition of the early stages of gap-fill. The local forest type also seemed to contribute most to seed bank composition. As rarer species tended to have clumped distributions, and 'safe sites' for regeneration seemed not to be limiting, dispersal constraints were argued to be the most likely factors slowing diversification, unless further severe volcanic disturbance leads to successional set-back. The latter also strongly limits the predictability of succession on Krakatau.

Thesis (M.S.)--Montana State University--Bozeman, 2004. / Typescript. Chairperson, Graduate Committee: Roger L. Sheley. Includes bibliographical references.

Identifying the diversity of contexts that can lead to hybridization is important for understanding its prevalence and dynamics in natural populations. Despite the potential of ecological succession to dramatically alter species co-occurrence and abundances, it is unknown whether it directly promotes hybridization and, if so, has long-lasting consequences. Here, we summarize 30 years of survey data across 10 populations to show that in western and mountain bluebirds, heterospecific pairing occurs during repeatable and transient colonization events at the early stages of species turnover. Despite mixed pairing occurring only during early succession, genetic data showed presence of hybrids at both early and late successional stages. Moreover, hybrids showed novel patterns of variation in morphology and behavior, emphasizing that even ephemeral contexts for hybridization can have important evolutionary consequences. Our results suggest that because ecological succession often brings together closely related competitors in disparate numbers but lasts for only a brief period of time, it may be a widespread but underappreciated context for hybridization.

Neste trabalho investigamos como são as interações discursivas que podem levar à promoção da enculturação científica durante uma atividade de trabalho de campo, relacionado à Ecologia, em uma área reflorestada. Várias perspectivas do campo da linguagem e ensino de Ciências nortearam este trabalho, dentre elas as pesquisas que consideram que a prática da argumentação em aula seja essencial para aprender Ciências, já que argumentar é inerente ao próprio discurso científico. Concebendo a Ciência como cultura, outras pesquisas discutem a importância de se envolver os alunos em atividades nas quais eles aprendam linguagens, regras, valores, conceitos da Ciência e como ela é construída ao longo do tempo, de forma a se posicionarem criticamente diante de situações que envolvam tomadas de decisões respaldadas em conhecimento científico. Contudo, raras atividades desenvolvidas em espaços não formais de ensino são amparadas pelos pressupostos apontados anteriormente, como por exemplo, os trabalhos de campo em ambientes naturais. Versando sobre os aspectos mencionados, foi elaborada uma atividade subdividida em três episódios: contextualização do trabalho de campo, realização do trabalho de campo e discussão dos dados coletados no trabalho de campo. O primeiro e o terceiro episódios ocorreram no Laboratório de Ensino de Biologia e o desenvolvimento do trabalho de campo ocorreu dentro da Floresta da USP, ambos no campus de Ribeirão Preto. Metodologias provenientes da Ecologia de Comunidades Vegetais foram empregadas, problematizando-se os possíveis estágios de sucessão ecológica do ambiente. Participaram da atividade dois monitores (estudantes do curso de Ciências Biológicas da USP, do mesmo campus) e alunos do sétimo ano do ensino fundamental. Inicialmente, toda a atividade foi videogravada e transcrita. Sua análise se deu com base nos elementos estruturais do Padrão de Argumentação de Toulmin e na verificação dos tipos de situações discursivas presentes. Averiguou-se, então, que turnos de falas durante toda a atividade compuseram um argumento geral construído a partir do problema proposto no trabalho de campo. Poucos argumentos pontuais também foram encontrados. No entanto, as falas dos alunos contribuíram minimamente com a construção de ambos os argumentos, predominando as falas dos monitores. Constatou-se também que aos alunos foi proporcionada uma vivência na qual um argumento, previamente delineado pelos monitores, pouco a pouco foi constituído. Porém, o contexto de produção desse argumento foi uma situação explicativa, a qual pode ser identificada pelos marcadores \"presença de uma única ideia (opinião)\" e \"justificativa de uma única ideia (opinião)\". / In this research we investigate the discursive interactions that may lead to the promotion of scientific literacy during a field work activity related to Ecology in a reforested area. Many perspectives in the field of language and science teaching guided this study, among them the researches that consider that the practice of argumentation in the classroom as essential to learning science, since arguing is inherent to scientific discourse. By designing science as culture, other studies discuss the importance of engaging students in activities in which they learn languages, rules, values, scientific concepts, and for the construction of science over time in order to position themselves critically in situations involving decision making using scientific knowledge as support. However, few activities in non-formal education are supported by the assumptions mentioned earlier, for example the fieldworks in natural environments. Dealing with the aspects mentioned above, was prepared an activity divided into three episodes: contextualization of the fieldwork, completion of fieldwork and discussion of data collected in the field. The first and third episodes occurred in the Biology Teaching Laboratory and the development of the field work took place within the USP Forest, both on the Ribeirão Preto campus. Methodologies from the Ecology of Plant Communities were used, questioning the possible ecological succession stages in the environment. Two monitors (Biology grad students from the same campus) and students of the seventh year of elementary school participated in the activity. Initially, all activity was videotaped and transcribed. Its analysis was based on structural elements of Toulmin Argumentation Pattern and on the verification of the present types of discursive situations. It was found then that shifts speeches throughout the activity composed a general argument constructed from the proposed issue in the fieldwork. Few specific arguments were found. However, the speech of students contributed minimally to the construction of both arguments, predominating the speeches of monitors. It was also found that students were provided an experience in which an argument previously outlined by the monitors, had been gradually established. However, the production context of this argument was an explaining situation, which can be identified by markers\' \"presence of a single idea (opinion)\" and \"justification of a single idea (opinion)\".