Thesis (MSc. Agriculture (Pasture Science)) -- University of Limpopo, 2016. / The relationships between tree age, growth rings, and stem circumference correlated with establishment patterns may be a valuable instrument to reveal the functioning of woody species in the Savanna Biome. A study on tree age and establishment patterns of Acacia tortilis in the semi-arid regions of the Limpopo Province was conducted to aid an understanding of the causes of encroachment in savanna vegetation. This study aimed to determine the periodicity of growth ring formation at two study areas, correlate the number of growth rings with different tree characteristics and document tree population establishment patterns of Acacia tortilis, using stem circumferences. This was done in order to predict long-term bush encroachment using the interaction between rainfall and soil on the age, growth and establishment patterns of Acacia tortilis. Data was collected at three sites representing two study areas, two sites at the University of Limpopo’s Syferkuil Agricultural Experimental Farm and one site at the Sondela Nature Reserve in the Limpopo Province. The study incorporated two different soil forms and two rainfall regimes. Trees were divided into five height classes; namely, <0.5 m, >0.5 – 1.5 m, >1.5 – 2.0 m, >2.0 – 3.0 m and >3m. Fifty trees (ten in each class) were felled at each site, and the following recordings were made: tree height, stem circumference and crown diameter. Furthermore, each felled stump was taken to the laboratory and examined for growth rings. The results indicated that growth pattern of Acacia tortilis stems were more influenced by soil form than the amount of rainfall. Tree height was not significantly affected by soil form. However, rainfall proved to have a significant effect on the final height of the plant. Both rainfall and soil form did not have a substantial effect on the number of growth rings. Crown diameter was affected by soil form but rainfall did not prove to have the same effect. Correlations between growth rings and stem circumferences, tree height and crown diameter, proved to have significant relationships. However, the relationship between stem circumference and the number of growth rings was the most significant. iv A prediction model was created using the relationship between stem size and growth rings. Using this model tree age can be determined in a non-destructive manner. However, the absence of a correlation between rainfall and establishment strongly suggests that rainfall cannot be used, on its own, to determine the establishment sequence and the pattern of bush encroachment. The study suggests that natural developments responsible for establishment patterns and population dynamics of woody species are complex, and their effects are visible after an extensive period. Therefore, to understand these influential processes comprehensively, several seasons of observations and monitoring would be recommended. Future research on this particular topic should include more than one encroaching species, because this will provide a broader perspective on the encroachment patterns of bush communities. However, the focus should be on studying the influence of growth limiting factors such as soil and climatic impacts, as well as area-specific environmental factors on the growth of encroaching species, such as Acacia tortilis. Key words: Bush encroachment, dendrochronology, growth rings, tree age, savanna, stem circumference Note: The candidate and the supervisors are aware of the fact that the Acacia genus has been revised. However, in this dissertation, the genus and species Acacia tortilis is still used. Relevant changes will be used in future publications. / University of Limpopo’s Department of Agriculture and National Research Foundation

Thesis (M.Sc. Agriculture (Pasture Science)) -- University of Limpopo, 2021 / Savanna rangelands are ecosystems which are characterized by the co-existence of scattered trees and shrubs with a continuous grass layer. However, the grass and tree balance has been highly altered as a result of disturbances caused by bush encroachment. Encroaching woody species have been shown to decrease species richness and abundance of the seed bank and ground‐layer diversity. So far little is known on the effect of bush encroachment and soil depth on the soil seed bank diversity in savanna rangelands. The objectives of this mini-dissertation were to (1) determine the influence of soil depth on soil seed bank diversity in bush encroached savanna rangelands, and (2) determine the relationships between soil seed bank herbaceous vegetation and physicochemical properties in encroached rangeland. In order to address these objectives, a savanna rangeland was demarcated into two encroachment gradients spanning from open to encroached rangeland. Within each encroachment gradient, six plots of 10 m x 10 m were randomly selected, whereby soil sampling and herbaceous vegetation were carried out and determined. In each replicate plot per encroachment level, five soil samples were randomly collected at 0-10 and 10-20 cm depths. The number of seedlings of different species emerging from the soil samples was used as a measure of the number of viable seeds in the soil and the composition of the seed bank using the seedling emergence method. The total seed densities showed significant differences (P<0.05) in the 0-10 cm depth layer in the open rangeland and encroached rangeland. Bush encroachment significantly (P<0.05) decreased the seed density of perennial grasses, specifically in 0-10 cm depth layer. Further, species diversity increased with bush encroachment in the 10-20 cm depth layer. Menhinick’s richness index showed no significant difference in the open and encroached rangeland, while species evenness decreased in the 0-10 cm depth layer and increased at 10-20 cm depth.The study also revealed negative correlations between organic carbon, calcium, clay, silt and forbs while mean weight diameter (MWD), a measure of soil aggregate stability was positively correlated with forbs. The canonical correspondence analysis (CCA) showed that pH, phosphorus, potassium and calcium were positively correlated to Eragrostis curvula and magnesium was negatively correlated to Panicum maximum. In open rangeland, CCA revealed that clay content was negatively correlated with species evenness while xii magnesium was negatively correlated to the Shannon Weiner index. Further, silt content was positively correlated with species richness and evenness. In the encroached rangeland, the CCA showed a negative correlation between magnesium and the Shannon Weiner index. The Sørensen’s index between soil seed banks and aboveground vegetation was low with index values of 0.22 and 0.24 in open and encroached rangeland, respectively. / AgriSeta

Thesis (M.Sc. Agriculture (Soil Science)) -- University of Limpopo, 2021 / Woody plant encroachment results in the degradation of grasslands. It is defined here as the increase in density, cover and biomass of woody plants into formerly open grasslands, reducing grassland productivity. Globally, many arid and semi-arid savanna grasslands are affected by this land cover transformation which changes the vegetation structure by altering the ratio of woody plants relative to grass species and influences soil hydrology. In the existing literature there is limited information on the effects of woody plant encroachment on soil physical and hydrological properties, especially in savanna grasslands. This study quantified and compared the soil physical and hydrological properties in the topsoil and subsoil of open and woody plant encroached grassland sites located on two contrasting soil forms, namely Bainsvlei and Rensburg. To achieve this objective, the two soils were sampled at various depth intervals from dug soil profiles at both sites at Towoomba Research Station in Bela Bela, Limpopo Province, South Africa. Soil physical properties including bulk density, porosity and aggregate stability as well as hydrological properties (water retention and hydraulic conductivity) were determined from collected samples. Compared to open grassland, soil bulk density was 11% and 10% greater in the topsoil and subsoil, while porosity was respectively 6% and 9% lower in the topsoil and subsoil of woody plant encroached grassland for Rensburg soils. In Bainsvlei soil, there was a minimal increase and decrease in the soil bulk density and porosity, respectively. Soil aggregate stability increased by 38% in the subsoil of woody plant encroached grasslands in Rensburg soil, due to increasing clay content with depth. In Bainsvlei soil, the soil aggregate stability was 9% and 13% lower in the topsoil and subsoil of the woody plant encroached grasslands compared to open grassland. Furthermore, the results revealed that in both soils, there was lower soil water retention and hydraulic conductivity in the topsoil and subsoil layers of woody plant encroached grassland than in open grasslands. There were no significant differences observed for soil hydraulic conductivity in the Bainsvlei and Rensburg topsoil. The subsoil hydraulic conductivity decreased by 24% in Bainsvlei and 44% in Rensburg soils in the woody plant encroached grassland. The soil water retention (SWR) decreased with an increase in woody plants. Specifically, there was 25% and 42% decrease in SWR with woody plant encroachment in the topsoil and subsoil of Bainsvlei soil, respectively. The same trend was observed in the Rensburg soils with 50% and 19% decrease in SWR in the topsoil and subsoil, respectively. Overall, the results revealed that soil type and depth influenced soil physical and hydrological properties in the studied woody plant encroached savanna grassland. As such, interventions aimed at controlling woody plant encroachment need to factor in soil type and depth in the development of management practices tailored to improve the soil hydrology of savanna grasslands

Thesis (M. Sc. Agriculture (Soil Science)) -- University of Limpopo, 2021 / Globally and in most parts of South Africa, there is a trend of increasing shrub encroachment in savanna rangelands. A number of studies have investigated the impact of shrub encroachment on soil organic carbon content (SOC) and soil organic carbon stocks (SOCs) in savannas. So far there is no clear consensus on whether shrub encroachment increases or decreases the level of SOC and SOCs, especially in semi arid savanna grasslands. Furthermore, knowledge on the effects of shrub encroachment on SOCs is largely restricted to the topsoil, as this is the part of the profile influenced by inputs and losses of soil organic matter. How shrub encroachment affects the vertical distribution of SOCs is rarely considered in the existing literature and the edaphic factors controlling SOCs with depth are poorly understood. The objectives of this study were (i) to quantify the vertical distribution of SOC and SOCs and (ii) to identify the edaphic factors controlling the vertical distribution of SOC and SOCs in a shrub-encroached savanna grassland sited on shallow plinthic soil. To achieve the objectives, a vegetation and soil survey of the savanna grassland was conducted whereby sampling areas were demarcated and characterized into open and shrub encroached grassland plots. In each encroachment level, three pits were randomly dug to the limiting layer on plots sited on the same soil type and similar topographic position. Soil samples were collected from the pits at depth intervals of 0-10, 10-20, 20-30, 30-40, 40-50, 50-60 and 60-70 cm. The collected soil samples were analyzed for chemical and physical properties in the laboratory. Correlation analysis was carried out to determine the relationship between SOC and SOCs, which were the variables of interest in this study and related controlling soil physicochemical properties. The results showed that SOC was significantly greater (P<0.05) in the shrub-encroached grassland compared to open grassland. Furthermore, the results revealed that SOC was on average 19 and 13% greater in the topsoil (0-20 cm) and subsoil (20-70 cm) of shrub encroached grassland compared to open grassland. The greater SOC in the topsoil of the shrub-encroached grassland was mainly attributed to higher SOC inputs from plant litter and detritus derived from trees and grasses, which are the dominant plant life forms in savannas. In the topsoil, SOC and SOCs were positively correlated with extractable phosphorus (P) (r = 0.60; P < 0.05), while in the subsoil they were positively correlated ix with extractable phosphorus (r = 0.54), soil porosity (r = 0.52), extractable copper (r = 0.46), extractable zinc (r = 0.41), exchangeable calcium (r = 0.37) and negatively correlated with mean weight diameter (r = -0.43). Overall, SOC and SOCs under both shrub-encroached and open grasslands vertically decreased with soil depth. The results obtained highlighted that the factors controlling the level of SOC and SOCs differs in the topsoil and subsoil of the studied shrub encroached grassland. These findings suggest that in the shallow plinthic soil investigated in this study, SOC in the topsoil is controlled by the macronutrient P, while in the subsoil it is physically protected by soil aggregates and chemically stabilized via complexation interactions with exchangeable cations and heavy metals. In-depth understanding of the physico-chemical factors controlling SOC storage is critical to foster management practices that will improve the cycling of SOC in shrub-encroached savanna grasslands.

Background: In light of the multitude of different channel options consumers have at hand and the rapidly advancing vertical integration of established brand manufacturers across industries, the question arises as to the basis on which consumers make their channel decision for a manufacturers direct-to-consumer (D2C) sales channel. Scholars have found that channel attributes and product-related factors generally play a pivotal role in consumer channel choice and have shown the influence they have on offline versus online channel choice. However, research in the context of established brand manufacturers offering D2C sales channels is so far underrepresented in the consumer channel choice literature despite its high current relevance. Purpose: This study investigates which channel attributes and product-related factors influence a consumer’s decision to fulfill a purchase through a manufacturer’s online D2C channel and how they do so, in order to gain insights into this so far insufficiently studied research context. Method: The data of this qualitative, explorative study was generated through semi-structured interviews with 16 purposefully selected samples. The sample was segmented demographically into four groups ranging from Baby Boomers to Generation Z, in which men and women are equally represented to create a heterogenous sample set. The data analysis followed an inductive approach using thematic analysis. Conclusion: This study found that 12 channel attributes and 8 product-related factors are relevant to consumer channel choice in the context of established manufacturers’ D2C channels.  Furthermore, it was found that channel choice is not exclusively based on the aforementioned, but that the individual factors are also interrelated. Particularly important are also influencing factors, which further affect consumer channel choice. Lastly, all identified factors are evaluated in tandem. A conceptual framework depicting these findings was developed.

Over the 21st century, climate change and wetland habitat loss will pose major threats to the Eastern Massasauga (Sistrurus catenatus), a federally threatened and Great Lakes region endemic rattlesnake. I collected capture-recapture data from sites across the range and modeled the effect of climatic variables on growth rate and asymptotic size. I found that high snow residence time was associated with larger asymptotic sizes but slower growth, while high spring precipitation increased growth rate. I then projected future growth and size under different carbon emission scenarios. Given the threat posed by successional encroachment of woody vegetation, I used spatially explicit capture-recapture models to examine the effects of landscape characteristics and phenology on the spatial distribution of density for a population in Michigan. I found highest density in areas close to a stream and with low vegetation intensity, which can inform prescribed burn programs and give additional insights into life history.

Thesis (MScConEcol (Conservation Ecology and Entomology))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Two populations of Acacia mellifera were noted in Pniel, which is a semi-arid savanna, near Kimberley in the Northern Cape province of South Africa. One population appeared on a rocky, andesitic laval ridges (soil pHKCL 6.5-7.0) along the Vaal river. The other appeared in a sandveld area (soil pHKCL 4). Bush encroachment by A. mellifera was found to be more extensive on the rocky areas than in the sandveld and the two habitats differed extensively on soil pH, clay and silt contents and also on water holding capacities. The rocky habitat was thus deduced to have a higher CEC. Seeds were sampled on a logarithmic scale for allozyme analysis and also randomly in each of the two habitats for local adaptation tests, in which case lime (CaCO3) and organic matter (cow-dung) were used in a completely-crossed design. Detected interaction effects (between population source and pH; population source and organic matter and between pH and organic matter) and significant differences could not separate the two populations as the differences occurred across populations. Random genetic differences leading to phenotypic plasticity in the two observed populations, might be responsible for the observed phenotypic differences. Allozymic data showed no significant differences between the two populations and the genetic distance between and within the populations also confirmed that the two populations had not genetically differentiated. The Mantel Test on the two populations, showed nonsignificant results. Nei‟s UPGMA dendrogram revealed that the game farm subpopulations were more primitive and genetically related to each other. Despite differences in allozyme frequencies, between the sampled sites, genetic differentiation was found to be low (FST = 0.337). Nei‟s (1972) original measures of genetic distance ranged between 0.871 and 1.000 with a mean of 0.949 ± 0.053. The study concluded that the two observed populations had not genetically differentiated and no local adaptation could be established rather phenotypic plasticity was evident and resulted in the observed divergent growth forms. Nonetheless, the overall direction of spread of encroachment appeared to be the eastward. / AFRIKAANSE OPSOMMING: Twee bevolkings van Acacia mellifera is gevind in Pniel, wat „n semi-ariede savanna is naby Kimberley in die Noord-Kaap provinsie van Suid-Afrika. Een bevolking het voorgekom op klipperige andesitiese lava riwwe (grond pHKCL 6.5-7.0) al langs die Vaalrivier. Die ander het voorgekom in „n sandveld area (soil pHKCL 4). Bos-oorskryding deur A. mellifera was meer uitgebreid op die klipperige areas as in die sandveld en die twee habitats het noemenswaardig verskil ten opsigte van grond pH, klei en silt inhoud asook waterhoukapasiteit. Dit kan was dus afgelei word dat die klipperige habitat „n hoër CEC het. Die sade was versamel op „n logaritmiese skaal vir allosiem-analise en ook ewekansig in die twee habitats vir lokale aanpassings toetse. In dié gevalle was kalk (CaCO3) en organiese material (koeimis) gebruik in „n totaal-gekruisde ontwerp. Bespeurde interaksie effekte (tussen bevolkings bron en pH; bevolkings bron en organiese material en tussen pH en organiese material) en noemenswaardige verskille kon nie die twee bevolkings skei nie, aangesien die verskille voorgekom het regdeur die twee bevolkings. Ewekansige genetiese verskille wat lei tot fenotipiese plastisiteit tussen die twee waargeneemde bevolkings mag dalk verantwoordelik wees vir die waargeneemde fenotipiese verskille. Allosiem-data het geen beduidende verskille gelewer tussen die twee bevolkings nie en genetiese afstand binne en tussen die bevolkings het ook bevestig dat die twee bevolkings nie geneties gedifferensiëer is nie. Die Mantel toets op die twee bevolkings het geen beduidende resultate gelewer nie. Nei se UPGMA dendogram get gewys dat die wildsplaas bevolkings was meer primitief en geneties verwant aan mekaar. Ten spyte van die allosiem frekwensies tussen die gemonsterde gebiede, was die genetiese differensiasie laag (FST = 0.337). Nei (1972) se oorspronlike meeting van genetiese afstand het tussen 0.871 en 1.000 beloop met „n gemiddeld van 0.949 ± 0.053. Die studie het bepaal dat die twee waargeneemde bevolkings nie geneties gedifferensiëer het nie en dat geen lokale aanpassing teenwoordig was nie. Fenotipiese plastisiteit was duidelik waarneembaar en het gelei tot die divergerende groeivorme. Nieteenstaande, was die algehele rigting van oorskryding ooswaarts.

This study is based in Tana River National Primate Reserve (TRNPR), Kenya. The reserve, established in 1976 to protect remnant patches of riverine forests from increasing human pressure is home to two endemic endangered primate subspecies, Tana River Red colobus (Colobus badius rufomitratus) and Tana River Crested mangabey (Cercocebus galeritus galeritus). Habitat encroachment through indigenous farming and forest uses was thought to be one of the causes of drastic colobus and mangabey population decline after 1975. This study aimed at; generating information on the impact of these human land-uses on the habitat, this would facilitate the preparation of management recommendations which would improve the chances of survival of primate habitats without compromising the welfare of indigenous people. Using 3 sets of aerial photographs and a geographic information system, information on land-use changes over time has been generated. A 3 month field work generated information on agriculture, forest uses and other relevant socio-economic information. Results from the study indicate that: (i) human population has increased by more than two-folds between 1969 and 1991; (ii) this has not corresponded to a net increase in forest area decrease or farm area increase; (iii) there has been a net increase in area under forest and decrease in area under agriculture; (iv) spatial and temporal changes in forest area explain colobus population crash observed between 1975 and 1985, (v) indigenous farmers interviewed prefer a compromise, where they are allowed controlled access to land within the reserve. They showed a keen knowledge of conservation costs and benefits and cause-effect processes between humans and the environment. Management recommendations advocate measures that encourage indigenous people to be partners in conservation.

Many natural areas and systems within urban landscapes are small or narrow. Landscape ecology studies within forested and agricultural landscapes have found that small natural areas that are protected from development or resource extraction through land use planning are significantly affected by adjacent land use changes. Some eventually lose the values for which they were protected. Studies also indicate that natural area boundary structures and functions are important determinants of the extent to which external threats affect adjacent natural areas. Few studies have empirically tested whether small or narrow urban natural areas that are protected from development through municipal land use planning are significantly affected by adjacent land use changes. However, municipal planners and forest managers are concerned that activities of residents living adjacent to the forest edge, commonly referred to as residential encroachment, may be degrading the social values, and ecological forms and functions of their woodlands. Studies have recorded evidence of human impacts within suburban forest edges, indicating that both recreation and yard-related activities are occurring and that these activities occur at significantly higher frequencies in the forest edge than in the interiors of these forests. However, no study has differentiated residential encroachment activities from those of other recreationists. In addition, although a number of municipalities have developed policies to address these activities, little is known about these policies, the extent to which they are implemented, or their effectiveness in protecting their small or narrow forested natural areas from residential encroachment activities. The principal research questions answered in this research are: 1) Do municipalities within Southern Ontario have policies for protecting natural areas from the activities of residents living adjacent to suburban forest edges? 2) To what extent are they implementing these policies? 3) What encroachment activities, if any, are occurring in Southern Ontario municipal forest edges? and 4) Are municipal boundary-related policies effective in limiting edge-resident encroachment activities? Using a mixed method approach, the research incorporates qualitative and quantitative data collection to answer these questions. The content analysis of official and secondary plans and social surveys of key informants within six Southern Ontario municipalities identify boundary-related policies for protecting municipal natural areas from residential encroachment activities. They also determine the extent to which the study municipalities implement these policies. Field studies in 40 forests within these municipalities used unobtrusive measurements of encroachment behaviour to describe encroachment activities under two implemented municipal boundary demarcation policies, and other boundary treatments The three research methods, together with a literature review, were used to determine whether Ontario municipal policies are effective in limiting edge-resident encroachment activities within municipal forest edges. The content analysis and interviews indicated that, in general, municipal policies were insufficient to address the edge-resident encroachment issue. Policies had been established, but not at a sufficiently authoritative policy level (i.e. the official plan level) to support their implementation by staff. In addition, policies were missing explicit goals, objectives and strategies to direct their implementation, and the municipalities had not integrated their disparate policy components into an integrated course of action through time and space. The municipalities were successful in implementing policies to prevent edge resident encroachment within natural areas adjacent to newly developing subdivisions. However, they had infrequently implemented their policies for preventing encroachment within natural areas adjacent to established subdivisions. Furthermore, all the municipalities were not frequently implementing their policies to remediate existing encroachments within natural areas adjacent to newly developing or established subdivisions. The unobtrusive measurement of encroachment behaviour confirmed that residential encroachment activities generated a housing effect zone of impact within municipal forest edges. The distribution of the evidence of encroachment was significantly biased to the forest border. Encroachment traces were highly prevalent within study forests, occurring in over 94% of sites and covering 26 to 50% of the sampled area. Encroachment traces were particularly intense in the first 8 metres from the forest border; but extended a mean maximum extent of 16 metres from the forest border, with 95% of the evidence of encroachment lying within 34 metres. Boundary type significantly affected the mean frequency, intensity and maximum extent of encroachment. Mean frequencies, intensities and extents of all encroachment, and of most encroachment categories, were generally higher in sites with boundary types that allowed edge residents ready access to the forest edge. Conversely, sites with boundary treatments that had barriers to entry, such as fences or grass strips, tended to have lower encroachment levels. Sites with multiple barriers, such as those with fences, grass strips and paths, tended to have the lowest mean frequencies, intensities and mean maximum extents of encroachment. While sites with implemented municipal post and fence policies had significantly lower mean frequencies, intensities and, in the case of fences extents of encroachment, they were not significantly different from those of sites under some of the boundary types not subject to municipal policies. They were also significantly higher than those of sites with fences and grass strips (with or without pathways). Sites with municipal posts had significantly lower mean intensities of encroachment than sites with other boundaries that enabled residents to enter the forest edge, and had significantly lower mean frequencies of waste disposal traces than fenced sites. Sites with fences also had significantly lower mean intensities of encroachment than sites with no boundary demarcation, or sites with fences and gates, and were particularly effective in reducing the incidence of yard extension encroachments, and mean maximum extents of encroachment. Despite the effectiveness of these boundary demarcation policies, and that of some of the other boundary treatments evaluated, none of the boundary treatments was effective in eliminating encroachment traces. A buffer of between 10 and 20 metres in width would be required to segregate the mean maximum extent of encroachment activities from sensitive forest edges, depending on the boundary demarcation policy, or type. The research concludes that current municipal policies are insufficient to meet the complexity and scope of the encroachment activities occurring. Some preventative policies have been developed and are regularly implemented within natural areas adjacent to new subdivisions. However, implemented boundary demarcation policies are insufficient to eliminate, or minimize residential encroachment. Wider more complex boundary policies that limit different types of encroachment and include elements that reduce access, spatially separate, and encourage informal residential surveillance (such as fences, grass strips and pathways) can further reduce encroachment levels. Few municipalities have established boundary demarcation policies to prevent encroachment within natural areas adjacent to established subdivisions, and study municipalities infrequently implement policies and bylaws to mitigate existing encroachments within these areas. Yet interviewees, and the results of the unobtrusive measurement of encroachment in study forest edges, indicate that encroachment activities are highly prevalent within these municipal forests. Policies at all levels, and particularly at the official plan level, are required to protect natural areas from edge resident encroachment, and other forms of post development impacts on natural areas. These policies are required to support the more rigorous enforcement of encroachment bylaws, and the negotiation, and implementation of effective buffers and boundary demarcation treatments. In consideration of these results and conclusions, the dissertation describes the implications for municipal planning policy and urban and regional planning theory, and provides recommendations for future research.

Many natural areas and systems within urban landscapes are small or narrow. Landscape ecology studies within forested and agricultural landscapes have found that small natural areas that are protected from development or resource extraction through land use planning are significantly affected by adjacent land use changes. Some eventually lose the values for which they were protected. Studies also indicate that natural area boundary structures and functions are important determinants of the extent to which external threats affect adjacent natural areas. Few studies have empirically tested whether small or narrow urban natural areas that are protected from development through municipal land use planning are significantly affected by adjacent land use changes. However, municipal planners and forest managers are concerned that activities of residents living adjacent to the forest edge, commonly referred to as residential encroachment, may be degrading the social values, and ecological forms and functions of their woodlands. Studies have recorded evidence of human impacts within suburban forest edges, indicating that both recreation and yard-related activities are occurring and that these activities occur at significantly higher frequencies in the forest edge than in the interiors of these forests. However, no study has differentiated residential encroachment activities from those of other recreationists. In addition, although a number of municipalities have developed policies to address these activities, little is known about these policies, the extent to which they are implemented, or their effectiveness in protecting their small or narrow forested natural areas from residential encroachment activities. The principal research questions answered in this research are: 1) Do municipalities within Southern Ontario have policies for protecting natural areas from the activities of residents living adjacent to suburban forest edges? 2) To what extent are they implementing these policies? 3) What encroachment activities, if any, are occurring in Southern Ontario municipal forest edges? and 4) Are municipal boundary-related policies effective in limiting edge-resident encroachment activities? Using a mixed method approach, the research incorporates qualitative and quantitative data collection to answer these questions. The content analysis of official and secondary plans and social surveys of key informants within six Southern Ontario municipalities identify boundary-related policies for protecting municipal natural areas from residential encroachment activities. They also determine the extent to which the study municipalities implement these policies. Field studies in 40 forests within these municipalities used unobtrusive measurements of encroachment behaviour to describe encroachment activities under two implemented municipal boundary demarcation policies, and other boundary treatments The three research methods, together with a literature review, were used to determine whether Ontario municipal policies are effective in limiting edge-resident encroachment activities within municipal forest edges. The content analysis and interviews indicated that, in general, municipal policies were insufficient to address the edge-resident encroachment issue. Policies had been established, but not at a sufficiently authoritative policy level (i.e. the official plan level) to support their implementation by staff. In addition, policies were missing explicit goals, objectives and strategies to direct their implementation, and the municipalities had not integrated their disparate policy components into an integrated course of action through time and space. The municipalities were successful in implementing policies to prevent edge resident encroachment within natural areas adjacent to newly developing subdivisions. However, they had infrequently implemented their policies for preventing encroachment within natural areas adjacent to established subdivisions. Furthermore, all the municipalities were not frequently implementing their policies to remediate existing encroachments within natural areas adjacent to newly developing or established subdivisions. The unobtrusive measurement of encroachment behaviour confirmed that residential encroachment activities generated a housing effect zone of impact within municipal forest edges. The distribution of the evidence of encroachment was significantly biased to the forest border. Encroachment traces were highly prevalent within study forests, occurring in over 94% of sites and covering 26 to 50% of the sampled area. Encroachment traces were particularly intense in the first 8 metres from the forest border; but extended a mean maximum extent of 16 metres from the forest border, with 95% of the evidence of encroachment lying within 34 metres. Boundary type significantly affected the mean frequency, intensity and maximum extent of encroachment. Mean frequencies, intensities and extents of all encroachment, and of most encroachment categories, were generally higher in sites with boundary types that allowed edge residents ready access to the forest edge. Conversely, sites with boundary treatments that had barriers to entry, such as fences or grass strips, tended to have lower encroachment levels. Sites with multiple barriers, such as those with fences, grass strips and paths, tended to have the lowest mean frequencies, intensities and mean maximum extents of encroachment. While sites with implemented municipal post and fence policies had significantly lower mean frequencies, intensities and, in the case of fences extents of encroachment, they were not significantly different from those of sites under some of the boundary types not subject to municipal policies. They were also significantly higher than those of sites with fences and grass strips (with or without pathways). Sites with municipal posts had significantly lower mean intensities of encroachment than sites with other boundaries that enabled residents to enter the forest edge, and had significantly lower mean frequencies of waste disposal traces than fenced sites. Sites with fences also had significantly lower mean intensities of encroachment than sites with no boundary demarcation, or sites with fences and gates, and were particularly effective in reducing the incidence of yard extension encroachments, and mean maximum extents of encroachment. Despite the effectiveness of these boundary demarcation policies, and that of some of the other boundary treatments evaluated, none of the boundary treatments was effective in eliminating encroachment traces. A buffer of between 10 and 20 metres in width would be required to segregate the mean maximum extent of encroachment activities from sensitive forest edges, depending on the boundary demarcation policy, or type. The research concludes that current municipal policies are insufficient to meet the complexity and scope of the encroachment activities occurring. Some preventative policies have been developed and are regularly implemented within natural areas adjacent to new subdivisions. However, implemented boundary demarcation policies are insufficient to eliminate, or minimize residential encroachment. Wider more complex boundary policies that limit different types of encroachment and include elements that reduce access, spatially separate, and encourage informal residential surveillance (such as fences, grass strips and pathways) can further reduce encroachment levels. Few municipalities have established boundary demarcation policies to prevent encroachment within natural areas adjacent to established subdivisions, and study municipalities infrequently implement policies and bylaws to mitigate existing encroachments within these areas. Yet interviewees, and the results of the unobtrusive measurement of encroachment in study forest edges, indicate that encroachment activities are highly prevalent within these municipal forests. Policies at all levels, and particularly at the official plan level, are required to protect natural areas from edge resident encroachment, and other forms of post development impacts on natural areas. These policies are required to support the more rigorous enforcement of encroachment bylaws, and the negotiation, and implementation of effective buffers and boundary demarcation treatments. In consideration of these results and conclusions, the dissertation describes the implications for municipal planning policy and urban and regional planning theory, and provides recommendations for future research.