Considered key landscape elements, ecotones play an important role in landscape ecology. In heavily fragmented, or heterogeneous landscapes, ecotones become a major, even dominant, feature. Yet, there are relatively few studies investigating communities of invertebrates associated with ecotones, especially across natural boundaries. Furthermore, most analyses of habitat loss do not consider the characteristics of the areas surrounding remaining habitat, the matrix. This thesis attempts to partially fill the gap. Afromontane forest-grassland ecotones are characteristically sharp (usually a few metres), are mainly fire-maintained, and have been in existence for, perhaps, millions of years. Therefore they provide a good opportunity to study ecotone, forest patch and grassland matrix characteristics together, and the associated species assemblages. In short, I investigated the diversity and distribution patterns of epigaeic invertebrates across ecotones between the natural and isolated patches of Afromontane forests and the surrounding natural grassland matrix, in the province of KwaZulu-Natal, South Africa. In particular, the following primary hypothesis was evaluated; do edge effects, in terms of elevated abundance and species richness, and in terms of abrupt, significant changes in environmental conditions, occur across near-natural ecotones. These edge effects quite often occur across anthropogenically-created habitat junctions, but it is not clear whether they do across natural ones. To test this hypothesis, the following secondary hypotheses were evaluated. Firstly, often a single invertebrate taxon is used for assessing changing landscape patterns. However, recent work has suggested that patterns and responses vary widely between taxa, and that management programmes based on the knowledge of a single taxon would not necessarily predict or safeguard that of others. Therefore, in chapter I, the hypothesis whether a single taxon could be used in biodiversity studies, or alternatively, whether it is better to select an array of taxa, was tested. Several invertebrate taxa were selected to investigate this. These included terrestrial amphipods, spiders, carabids, staphylinids and ants. Indeed, results showed that species diversities and assemblage-compositions of epigaeic spiders, carabids, staphylinids and ants were significantly different in different-sized Afromontane forest patches. Only carabids and staphylinids correlated positively with each other in terms of numbers of species. The other taxa showed only weak positive, or negative, correlations in their species richness. Results supported the multi-taxa approach in conservation studies, even among groups sharing a common habitat stratum. Secondly, organismal diversity usually increases at disturbed habitat edges. This phenomenon is commonly referred to as the biological edge effect. This pattern, however, is not universal and a number of authors have shown evidence contradicting this hypothesis. In chapter II amphipods, ground beetles and ants were collected to test the biological edge effect hypothesis. In addition, a number of abiotic factors were measured across these forest-grassland boundaries in an attempt to relate the biotic with the abiotic. Little evidence was found to support the classical edge-effect hypothesis (elevated species richness at the ecotone). In fact, carabid abundance and species richness was high in forests, decreasing gradually through the ecotone to a low in grasslands. In contrast, ant species richness increased significantly from a low in forests, increasing gradually through the ecotone, to a high in grasslands. Certain species did, however, show a significant increase in abundance at the ecotone, such as Talistroides africana, a terrestrial amphipod, and Tetramorium avium, a seed-predatory ant. Afromontane forest-grassland ecotones are natural and are not the result of anthropogenic clear-cut fragmentation. They also lacked any great changes in micro-environmental conditions. I hypothesise that edge effects are of less importance at more naturally maintained habitat boundaries even if these boundaries are sharp. Thirdly, climatic variation has a major impact on invertebrate communities. The Afromontane landscape experiences hot and wet summers, and cool and dry winters. I hypothesised that invertebrate distribution patterns across an ecotone change from one season to the next (chapter III). For example, it is expected that certain winter-active species might disperse from one location along the gradient to another, perhaps to escape predators, or find winter-refugia. This would, in turn, change the pattern of distribution of the selected taxa across these ecotones. Surprisingly, the general pattern of distribution across these ecotones changed little. However, there were significant differences between summer, spring, winter and autumn catch, and species identities changed from one season to the next. For example, carabid abundance and species richness was higher in the forest, compared to in the grassland, while ants were species richer in the grassland, compared to in the forest. These patterns were consistent from one season to the next. Again, as was found in chapter II, T. africana was significantly more abundant at the ecotone, compared to either forest or grassland interiors, in all seasons throughout the year. To summarise, amphipods favoured the ecotone environment, carabids the forests and ants the grasslands, throughout the year. Finally, scientists have recently become aware of the importance of the matrix surrounding habitat patches, in the survival and occurrence of organisms in the habitat patch. I tested whether the quality of the matrix, as a function of human disturbance, has an influence on invertebrate occurrence and distribution patterns across Afromontane forest-grassland boundaries. Redgrass (Themeda triandra Forssk.) dominated Afromontane grasslands are, and have been experiencing varying degrees of anthropogenic disturbance. Consequently, ecotones vary from being very abrupt (heavy disturbance in the matrix) to gradual (little disturbance in the matrix), although still sharp compared to most ecotones elsewhere. Level of grassland disturbance influenced amphipod, carabid and ant assemblage-structure across Afromontane ecotones (chapter IV). Results support the hypothesis that the dynamics of remnant areas are influenced by factors arising in the surrounding landscape. In particular, carabid assemblage-composition changed highly significantly from undisturbed to disturbed sites (this taxon was mainly captured from forests). Furthermore, only a single carabid individual was captured from 8 to 128 m into the grassland and only 14 T. africana individuals were captured from 2 m inside the forest to 128 m into the grassland of the most disturbed site. Clearly, matrix quality influenced not only the patterns of occurrence of organisms in the grassland matrix, but also at the ecotones and in the forest patches. In conclusion, it is imperative to investigate a number of taxonomic groups in conservation ecology to give more reliable results, and thus conservation recommendations. Of course, not all taxa can be considered, and the selection of appropriate taxa still poses a problem, but a set of taxa that are considerably different biologically is a good start. Native Afromontane forest-grassland mosaics are in urgent need of conservation, as much of this habitat is subject to heavy anthropogenic disturbance such as human settlement, forestry, cattle grazing, agriculture, and frequent, out of season, fires. Unfortunately only 2% of this biome is protected in South Africa. Furthermore, matrix quality is important because it determines the survival rate of propagules moving between remnant patches of habitat, and therefore the success rate of such movements. Private land-owners own most of this grassland area in the Afromontane region, but no guidelines are available to them on how to protect this habitat. Throughout this thesis I emphasised the importance of protecting both native forest and the surrounding native grassland. A first initiative is simply to protect a zone of grassland around the forest patches, both in terms of less frequent burning regimes, and less, or no cattle grazing here. By doing so, a rich grassland ant fauna will be conserved, the grassland matrix quality will improve, and a rich carabid fauna, favouring predominantly Afromontane forest remnants, will be conserved. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2000.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2006. / Härtill 4 uppsatser.

Thesis (M.S.)--Wake Forest University. Dept. of Biology, 2003. / Vita. Includes bibliographical references (leaves 51-57).

This diploma thesis was written to analyze and evaluate the changes of the landscape in selected cadastral communities with a finished complex landscape management. The analysis was completed in four time periods. It included a historical time period in 1952, a period before the landscape management, a period during the designing of landscape management and the present condition of the landscape. Changes that appeared in the landscape were evaluated for land use, the permanent landscape structure, the density of the road network and ecotones. According to the results of the diploma thesis it is possible to find out how the complex landscape management project for individual studied areas contributed on the progress of the changes of the landscape.

Transições de floresta-campo são encontradas em diversas regiões do mundo. Sob condições climáticas favoráveis, tem-se observado um padrão de aumento na densidade de lenhosas e expansão florestal sobre áreas de vegetação campestre. Este trabalho tem como objetivo identificar diferenças de composição de espécies lenhosas e composição funcional entre comunidades florestais e de transição, bem como identificar padrões funcionais destas comunidades em resposta a gradientes de clima e solo. Para tanto, foram coletados dados em 18 áreas de transição floresta-campo no sul do Brasil, considerando a densidade de espécies lenhosas e atributos foliares mensurados em cada habitat (floresta e transição). Os sítios de amostragem foram descritos por variáveis de clima e solo, gerando assim três matrizes ambientais (E): tipo de habitat, climática e edáfica. A análise dos dados envolveu ajustes de Procrustes entre matriz T (atributos médios da comunidade ponderados pela abundância das espécies) e matriz E (r (TE)) para detectar padrões de convergência de atributos, e entre diversidade funcional (R) e matriz E (r (RE)) para detectar padrões de divergência, relacionando estes padrões a cada matriz E. Os resultados indicaram padrões de convergência e divergência em relação à matriz de habitat. Comunidades florestais e de transição diferiram em termos de média de SLA e área foliar, e também quanto à diversidade funcional (ambos com valores maiores na floresta). Considerando os gradientes ambientais, as comunidades de ambos os habitats apresentaram padrões de convergência com o clima e o solo. Em matéria de clima, o principal resultado foi em relação ao SLA, com valores mais altos em áreas de florestas estacionais. Quanto ao solo, as comunidades florestais demonstraram uma associação de SLA e espessura da folha com o gradiente de matéria orgânica / fertilidade, porém as comunidades de transição não apresentaram padrões claros. Padrões de divergência em relação ao solo foram observados para ambos os habitats, mas só a floresta apresentou divergência em relação ao gradiente climático. Concluímos que, apesar das diferenças locais entre habitats em termos de composição de espécies lenhosas e estratégias funcionais, as comunidades de transição e de floresta estão respondendo de forma semelhante aos gradientes climáticos regionais. No geral, as espécies lenhosas demonstram ter estratégias funcionais relacionadas a atributos foliares que tem possibilitado o processo de adensamento de lenhosas em ecossistemas campestres em áreas de transição de floresta-campo. / Forest-grassland transitions are found in many different regions of the world. Through favorable climatic conditions, a pattern of woody encroachment and forest expansion over open grassy areas is observed. This work aims at identifying species composition and functional differences between forest and transition communities concerning woody plants, as well as functional patterns of communities in response to climate and soil gradients. We collected data in 18 forest-grassland transition areas in southern Brazil, considering woody plant species density and leaf traits that were measured for each habitat (forest and transition). Sites were described by climate and soil variables, leading to three different environmental matrices (E): habitat-type, climatic, and soil gradient. Data analysis involved Procrustes adjustment between matrix T (community-weighted mean traits) and matrix E (r(TE)) to detect trait-convergence, and between functional diversity (R) and matrix E (r(RE)) to detect patterns of divergence related to each matrix E. Results showed convergence and also divergence concerning the habitat-type matrix. Forest and transitional communities differed in terms of SLA and leaf area community-weighted means, and also in functional diversity. Concerning the environmental gradients, either forest or transition habitats presented convergence patterns with climate and soil gradients. Main results concerning climate were related to higher SLA at seasonal forest sites. As for soil, forest communities have demonstrated an association of SLA and leaf thickness with the organic matter/fertility gradient, but transition didn’t present clear patterns. Concerning alpha-divergence both habitats responded to soil gradients, but only forest presented divergence concerning climate. We conclude that although woody species of both habitats locally differed in species composition and their functional strategies, communities of forest and grassland transitions are responding similarly to broader climate gradients. Overall woody species seem to have leaf traits strategies that enabled the encroachment process of grassy ecosystems in forest-grassland transitions.

Transições de floresta-campo são encontradas em diversas regiões do mundo. Sob condições climáticas favoráveis, tem-se observado um padrão de aumento na densidade de lenhosas e expansão florestal sobre áreas de vegetação campestre. Este trabalho tem como objetivo identificar diferenças de composição de espécies lenhosas e composição funcional entre comunidades florestais e de transição, bem como identificar padrões funcionais destas comunidades em resposta a gradientes de clima e solo. Para tanto, foram coletados dados em 18 áreas de transição floresta-campo no sul do Brasil, considerando a densidade de espécies lenhosas e atributos foliares mensurados em cada habitat (floresta e transição). Os sítios de amostragem foram descritos por variáveis de clima e solo, gerando assim três matrizes ambientais (E): tipo de habitat, climática e edáfica. A análise dos dados envolveu ajustes de Procrustes entre matriz T (atributos médios da comunidade ponderados pela abundância das espécies) e matriz E (r (TE)) para detectar padrões de convergência de atributos, e entre diversidade funcional (R) e matriz E (r (RE)) para detectar padrões de divergência, relacionando estes padrões a cada matriz E. Os resultados indicaram padrões de convergência e divergência em relação à matriz de habitat. Comunidades florestais e de transição diferiram em termos de média de SLA e área foliar, e também quanto à diversidade funcional (ambos com valores maiores na floresta). Considerando os gradientes ambientais, as comunidades de ambos os habitats apresentaram padrões de convergência com o clima e o solo. Em matéria de clima, o principal resultado foi em relação ao SLA, com valores mais altos em áreas de florestas estacionais. Quanto ao solo, as comunidades florestais demonstraram uma associação de SLA e espessura da folha com o gradiente de matéria orgânica / fertilidade, porém as comunidades de transição não apresentaram padrões claros. Padrões de divergência em relação ao solo foram observados para ambos os habitats, mas só a floresta apresentou divergência em relação ao gradiente climático. Concluímos que, apesar das diferenças locais entre habitats em termos de composição de espécies lenhosas e estratégias funcionais, as comunidades de transição e de floresta estão respondendo de forma semelhante aos gradientes climáticos regionais. No geral, as espécies lenhosas demonstram ter estratégias funcionais relacionadas a atributos foliares que tem possibilitado o processo de adensamento de lenhosas em ecossistemas campestres em áreas de transição de floresta-campo. / Forest-grassland transitions are found in many different regions of the world. Through favorable climatic conditions, a pattern of woody encroachment and forest expansion over open grassy areas is observed. This work aims at identifying species composition and functional differences between forest and transition communities concerning woody plants, as well as functional patterns of communities in response to climate and soil gradients. We collected data in 18 forest-grassland transition areas in southern Brazil, considering woody plant species density and leaf traits that were measured for each habitat (forest and transition). Sites were described by climate and soil variables, leading to three different environmental matrices (E): habitat-type, climatic, and soil gradient. Data analysis involved Procrustes adjustment between matrix T (community-weighted mean traits) and matrix E (r(TE)) to detect trait-convergence, and between functional diversity (R) and matrix E (r(RE)) to detect patterns of divergence related to each matrix E. Results showed convergence and also divergence concerning the habitat-type matrix. Forest and transitional communities differed in terms of SLA and leaf area community-weighted means, and also in functional diversity. Concerning the environmental gradients, either forest or transition habitats presented convergence patterns with climate and soil gradients. Main results concerning climate were related to higher SLA at seasonal forest sites. As for soil, forest communities have demonstrated an association of SLA and leaf thickness with the organic matter/fertility gradient, but transition didn’t present clear patterns. Concerning alpha-divergence both habitats responded to soil gradients, but only forest presented divergence concerning climate. We conclude that although woody species of both habitats locally differed in species composition and their functional strategies, communities of forest and grassland transitions are responding similarly to broader climate gradients. Overall woody species seem to have leaf traits strategies that enabled the encroachment process of grassy ecosystems in forest-grassland transitions.

Transições de floresta-campo são encontradas em diversas regiões do mundo. Sob condições climáticas favoráveis, tem-se observado um padrão de aumento na densidade de lenhosas e expansão florestal sobre áreas de vegetação campestre. Este trabalho tem como objetivo identificar diferenças de composição de espécies lenhosas e composição funcional entre comunidades florestais e de transição, bem como identificar padrões funcionais destas comunidades em resposta a gradientes de clima e solo. Para tanto, foram coletados dados em 18 áreas de transição floresta-campo no sul do Brasil, considerando a densidade de espécies lenhosas e atributos foliares mensurados em cada habitat (floresta e transição). Os sítios de amostragem foram descritos por variáveis de clima e solo, gerando assim três matrizes ambientais (E): tipo de habitat, climática e edáfica. A análise dos dados envolveu ajustes de Procrustes entre matriz T (atributos médios da comunidade ponderados pela abundância das espécies) e matriz E (r (TE)) para detectar padrões de convergência de atributos, e entre diversidade funcional (R) e matriz E (r (RE)) para detectar padrões de divergência, relacionando estes padrões a cada matriz E. Os resultados indicaram padrões de convergência e divergência em relação à matriz de habitat. Comunidades florestais e de transição diferiram em termos de média de SLA e área foliar, e também quanto à diversidade funcional (ambos com valores maiores na floresta). Considerando os gradientes ambientais, as comunidades de ambos os habitats apresentaram padrões de convergência com o clima e o solo. Em matéria de clima, o principal resultado foi em relação ao SLA, com valores mais altos em áreas de florestas estacionais. Quanto ao solo, as comunidades florestais demonstraram uma associação de SLA e espessura da folha com o gradiente de matéria orgânica / fertilidade, porém as comunidades de transição não apresentaram padrões claros. Padrões de divergência em relação ao solo foram observados para ambos os habitats, mas só a floresta apresentou divergência em relação ao gradiente climático. Concluímos que, apesar das diferenças locais entre habitats em termos de composição de espécies lenhosas e estratégias funcionais, as comunidades de transição e de floresta estão respondendo de forma semelhante aos gradientes climáticos regionais. No geral, as espécies lenhosas demonstram ter estratégias funcionais relacionadas a atributos foliares que tem possibilitado o processo de adensamento de lenhosas em ecossistemas campestres em áreas de transição de floresta-campo. / Forest-grassland transitions are found in many different regions of the world. Through favorable climatic conditions, a pattern of woody encroachment and forest expansion over open grassy areas is observed. This work aims at identifying species composition and functional differences between forest and transition communities concerning woody plants, as well as functional patterns of communities in response to climate and soil gradients. We collected data in 18 forest-grassland transition areas in southern Brazil, considering woody plant species density and leaf traits that were measured for each habitat (forest and transition). Sites were described by climate and soil variables, leading to three different environmental matrices (E): habitat-type, climatic, and soil gradient. Data analysis involved Procrustes adjustment between matrix T (community-weighted mean traits) and matrix E (r(TE)) to detect trait-convergence, and between functional diversity (R) and matrix E (r(RE)) to detect patterns of divergence related to each matrix E. Results showed convergence and also divergence concerning the habitat-type matrix. Forest and transitional communities differed in terms of SLA and leaf area community-weighted means, and also in functional diversity. Concerning the environmental gradients, either forest or transition habitats presented convergence patterns with climate and soil gradients. Main results concerning climate were related to higher SLA at seasonal forest sites. As for soil, forest communities have demonstrated an association of SLA and leaf thickness with the organic matter/fertility gradient, but transition didn’t present clear patterns. Concerning alpha-divergence both habitats responded to soil gradients, but only forest presented divergence concerning climate. We conclude that although woody species of both habitats locally differed in species composition and their functional strategies, communities of forest and grassland transitions are responding similarly to broader climate gradients. Overall woody species seem to have leaf traits strategies that enabled the encroachment process of grassy ecosystems in forest-grassland transitions.

This research examines the history of a small Florida agricultural community over the course of the twentieth century from a rhetorical perspective in order to understand the technological and communicative transitions that governed the development of American agricultural production. By examining archival and oral histories, this research will add to our understandings of how written and oral communications temper the relationships and social situations of an agricultural community, including the knowledge-making and technological adaptation resulting from communications within the community and with outside institutions and entities. Agricultural villages are not isolated entities, but rather sites of multiple rhetorical situations, and farmers do not farm alone, but inside an ecosystem of networked knowledges, practices, and traditions. Thus, the history of a singular farming community may serve as a rhetorical microcosm of modern American agriculture's evolution over the course of the twentieth century, and provide some mindfulness concerning the social, technological, and natural ecologies that act and interact within modern farming communities. This dissertation will use rhetorical genre theory and ideas of local literacies to examine the written and oral discourses that run through these ecologies for the purpose of tracing the relationships between the sponsors of agricultural ideas and technologies and the local farmers who interpreted, employed, and modified them. In addition, this project purports to add to digital history-making research through the construction of an historical archival website to which community members can add their voices. The Samsula Historical Archive creates an online nexus where community members can document, organize, and preserve the history of the community, offering a portal supporting multiple narratives and perspectives. Each family has its own stories and perspectives on historical happenings; by bringing these together in one databased location, the layers and interconnections will become clearer and perhaps stimulate further memories and insights. A discussion of the rhetorical choices faced in constructing such an artifact may also help future researchers embarking on such a project.

published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy