Abstract To assess the symbiotic dependency of grain and shrub/tree legumes within five agro-ecological zones of Botswana, fully expanded leaves of the test species were sampled from about 26 study sites within Ngwaketse, Gaborone, Central, Ghanzi and Kalahari agro-ecological zones. Isotopic analysis revealed significant differences in 1)15N values of the grain legumes [cowpea (Vigna unguiculata L. Walp), Bambara groundnut (Vigna subterranea L. Verde.), and groundnut (Arachis hypogaea L.)] from the 26 farming areas in both 2005 and 2006. Estimates of %Ndfa of leaves also showed significant differences between farming areas, with cowpea deriving more than 50% of its N nutrition from symbiotic fixation. In terms of distribution, many more symbiotic shrub/tree species were found in the wetter Ngwaketse agro-zone compared to the fewer numbers in the drier Kalahari region. Acacias were the more dominant species at all sites. Leaf 1)15N values of shrub/tree species also varied strongly across Botswana, with 11 out of 18 of these legumes deriving about 50%, or more, of their N from symbiotic Nz fixation. Acacia caffra, in particular, obtained as much as 93.6% of its N nutrition from symbiotic fixation in the wetter Ngwaketse agro-zone. This study has shown that grain legumes sampled from farmer's fields in Botswana obtained considerable amounts of their N from symbiotic fixation. We have also shown that shrub and tree legumes probably play an important role in the N economy of the savanna ecosystems in Botswana. However, the decline in the number of functional Ny-fixing shrub/tree legumes along an aridity gradient suggests that soil moisture is a major constraint to Nz fixation in the tree legumes of Botswana.

Abstract To assess the symbiotic dependency of grain and shrub/tree legumes within five agro-ecological zones of Botswana, fully expanded leaves of the test species were sampled from about 26 study sites within Ngwaketse, Gaborone, Central, Ghanzi and Kalahari agro-ecological zones. Isotopic analysis revealed significant differences in 1)15N values of the grain legumes [cowpea (Vigna unguiculata L. Walp), Bambara groundnut (Vigna subterranea L. Verde.), and groundnut (Arachis hypogaea L.)] from the 26 farming areas in both 2005 and 2006. Estimates of %Ndfa of leaves also showed significant differences between farming areas, with cowpea deriving more than 50% of its N nutrition from symbiotic fixation. In terms of distribution, many more symbiotic shrub/tree species were found in the wetter Ngwaketse agro-zone compared to the fewer numbers in the drier Kalahari region. Acacias were the more dominant species at all sites. Leaf 1)15N values of shrub/tree species also varied strongly across Botswana, with 11 out of 18 of these legumes deriving about 50%, or more, of their N from symbiotic Nz fixation. Acacia caffra, in particular, obtained as much as 93.6% of its N nutrition from symbiotic fixation in the wetter Ngwaketse agro-zone. This study has shown that grain legumes sampled from farmer's fields in Botswana obtained considerable amounts of their N from symbiotic fixation. We have also shown that shrub and tree legumes probably play an important role in the N economy of the savanna ecosystems in Botswana. However, the decline in the number of functional Ny-fixing shrub/tree legumes along an aridity gradient suggests that soil moisture is a major constraint to Nz fixation in the tree legumes of Botswana.

MENVSC (Ecology and Resource Management) / See the attached abstract below

This study represents a continuation of the historical trend in the analysis of the relationships between climate and vegetation. The focus of the work is on an examination of the association of functioning plants and climatic processes and on the interaction of structured vegetation communities with their environment. Satellite observations and remote sensing technology provide new opportunities for studying the geo-biosphere at high temporal frequencies and for large geographic areas. Integration of spectral vegetation indices and thermal measurements from space is the prime methodology used in this study. The integration of thermal information with vegetation indices has the potential to result in an important contribution to ecological remote sensing. This study has investigated the triangular distribution pattern which has been repetitively observed in spectral domains defined by thermal measurements and vegetation indices. Results show that the triangular shape of an AVHRR data cluster can be consistently observed on different continents and at different times of the year. The triangular data pattern has also been observed using a seasonally averaged data set, representing the mean thermal and biomass conditions of a growing season. The triangular shape of the data spread in feature space clearly suggests an ecosystem triangle model for simulation of the global ecology. A closer analysis of 15 test sites representing the major biomes in the U.S. Southwest study area has shown that each biome has a stable territory in the two dimensional space of temperature and biomass. If the territory of each test site in the triangle can be viewed as a vegetation cell, the ecosystem as a whole may be modeled by using this cell structure. The ecosystem triangle model and the concept of the cell structure have been applied in a vegetation classification exercise. The significant improvement achieved in the vegetation classification supports the conclusion that the ecosystem triangle model is a reflection of surface biomes, and may be used as a tool to study the structure, organization, and function of the biosphere.

Archaeological data has increased significantly with Cultural Resource Management agencies finding and recording archaeological sites all across Utah. With the site data from the Utah State Historical Preservation Office, I examine the expansion of Archaic sites in the Eastern Great Basin from the Early Archaic through the Late Archaic, through the lens of elevation and ecological zones and proximity to wetland resources. I argue that the aridness of the Middle Holocene caused the people to expand into the mountains of Utah, and that the expansion continued into the Late Archaic period, even though the environment became more moist again. I also argue that the people of the Archaic stayed near to wetlands and wetland resources throughout the Archaic.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 190-196). Also available on the World Wide Web.

Development, environmental sustainability, agriculture and livelihoods are dimensions that are often considered antagonistic. By thinking at the landscape level however, innovative opportunities arise for simultaneity as these entities manifest spatially and require communication across disciplines. Trans-frontier Conservation Areas (TFCAs) embrace this thinking. These are large areas that cut across two or more international boundaries, include within them at least one Protected Area (PA) and other multiple resource use areas, including human dwellings and cultivated areas. Similarly, ecoagriculture is an innovative approach to land use management as it seeks to spatially synergise agriculture, livelihoods and biodiversity conservation across space and requires an awareness of landscape-level issues by land users, a condition which is not necessarily met. Such landscape thinking stems from the fact that if a piece of land is subject to rigorous conservation, it will fail if the surrounding areas are degraded. Additionally, it has been shown that agriculture often benefits from the nearby presence of natural areas for ecosystem services such as pollination, pest management, and erosion control. As such, multifunctional landscape mosaics together with small scale farmers, not large scale monocultures, are the key to global food security, as the former more effectively links agricultural intensification to hunger reduction. In order to ascertain an integrated understanding of the landscape concept, necessary for the formalisation of ecoagriculture, this study assessed the landscape perceptions and understandings held by local people residing within a TFCA. We employed participatory methods within the Mathenjwa Tribal Area (MTA), an area falling within the Lubombo TFCA and identified as holding ecoagriculture potential. Results revealed that local people perceive landscape as a function of subsistence utility. Local people perceive land-use multifunctionality, necessary for the formalisation of ecoagriculture, but at a smaller scale than expected depending on both social and biophysical interpretations. Landscape scale projects should incorporate local landscape understandings. / Dissertation (MA)--University of Pretoria, 2013. / Geography, Geoinformatics and Meteorology / MA / Unrestricted

Thesis (M.A. Agricultural Management (Animal Production)) -- University of Limpopo, 2020 / The Nguni is indigenous multi-purpose cattle breed that plays an important role in both commercial and communal farming systems in South Africa (SA). Unfortunately, the breed is currently under threat of diminishing due to farmers’ preference for exotic breeds and cross breeding. In recognition of the above, the Industrial Development Corporation, the Mpumalanga Department of Agriculture, Rural Development, Land and Environmental Affairs and the University of Limpopo established the Nguni cattle breed preservation project. In this project, a herd of 30 Nguni heifers and 1 bull were allocated to 34 Communal Property Associations (CPA) and 40 private farming enterprises each. With its three distinct ecological zones (High, Mid and Low-veld), the Mpumalanga province poses a challenge to the Nguni preservation project since cattle have to adapt to different ecological zones in order to grow and reproduce efficiently. Knowledge of cattle herd productivity improves the understanding of the functional attributes and is useful in determining the constraints and the potential of communal beef cattle production systems. Significant differences between ecological zones were observed for age at first calving, weaning rate, calves’ birth weight and calves’ weaning weight (p < 0.05). Calving of heifers in the Mid-veld zone occurred earlier (24 months) on both ownership types compared to Highveld (28.09 months for private and 26.00 for CPA) and the Lowveld (28.35 months for both ownerships). Nguni cattle on the Highveld performed better in terms of weaning rate under both private and CPA ownerships, where the weaning rate were 93% and 80%, respectively. Calves birth weight was lower in both ownership types in the Midveld zone (22.17 kg), whereas in the CPA, the Lowveld zone had higher calves birth weights (26.80 kg). In the private ownership, the highest calves’ birth weight (25.35 kg) was on the Highveld. The calves weaning weight were significantly higher (p < 0.05) on Highveld in private ownership (190.16 kg) and lowest (160.39 kg) in the Midveld zone. For the CPA, the highest calves weaning weight was also on the Highveld (187.55) and lowest on Midveld (167.50 kg). A full range of backup services that are offered to the communities by stakeholders in the form of a beef package that includes veld and pasture management, nutrition management, beef performance, animal recording keeping, genetic evaluation and animal health management program needs thorough attention.