Ecological land classification refers to an integrated survey in which areas of land, as ecosystems, are classified according to their ecological unity. In Canada, the approach was first advanced, nationally, in 1969 and was termed 'Bio-physical Land Classification'. This approach, which was derived from several foreign and domestic precedents, has been employed by various independent survey organizations throughout Canada to secure an ecological data bases for resource planning and management consideration. Because coordination was lacking between these organizations, modifications of this approach have taken place independently and often have been weighted according to the investigator's personal interests or capabilities. As such, the approach currently possesses a disparate character which is difficult to define singularly. To identify the current status in methodology, Canadian works in this field were comparatively analyzed. One result which stands out prominently from the analysis is that there are multifarious forms of ecological land classification. While they tend to achieve the same results, and demonstrate numerous commonalities land ecosystems have been manifested by combinations of criteria which are not always the same. Considerable confusion surrounds the nomenclature, the criteria for definitions and the criteria for recognition. Based on the analysis, hierarchical categories eco- province, ecoregion, ecodistrict, ecosection and ecotype are proposed. These are land ecosystems which possess a common recognized identity based on a unified pattern of biological and physical land characteristics. Each category coincides with a different order of generalization. Based largely on material extracted from past studies, criteria for recognition are stated. / Land and Food Systems, Faculty of / Graduate

Rapid increases in the global human population have led to agricultural intensification worldwide, highlighting the need for conserving the remaining fragmented natural areas and incorporating more sustainable farming techniques. South Africa is currently the largest producer of macadamia nuts in the world and macadamia plantings are increasing rapidly, resulting in the loss of natural vegetation. The study area, Hazyview in Mpumalanga, is an agricultural mosaic, with fragments of natural vegetation patches in between. These natural vegetation patches are key to retaining important ecosystem services for the agricultural industry such as pollination and pest-control. This study evaluated how a land-use mosaic, represented by an agricultural landscape with natural vegetation retained around the farms, is related with macadamia nut yield and quality, the activity of insectivorous bat species, and nocturnal insect abundance, with a specific focus on five different macadamia farms. The role and contribution of bats and insects in agro-ecosystems are becoming more apparent, and their importance as indicator species which can reflect environmental changes in plant and insect communities is of key value. With this information, I could gain a better understanding of the relationships between the surrounding biodiversity and the commercial macadamia nut production industry, as well as the potential impact that agriculture-induced landscape fragmentation has on the biodiversity in the region. Firstly, on-farm characteristics (e.g. tree age, density, height) for five farms were used, aswell as their yield and quality measures and land-use types surrounding each farm to determine potential relationships between macadamia nut yield and/or quality and proximity to surrounding natural vegetation. Farm characteristics such as the height and density of the macadamia trees planted had a significant association with yield and quality of the nuts which both decreased with increasing tree height and density. Additionally, a characteristic of land-use type (in this case, extent of waterbodies such as rivers/ dams and wetlands surrounding the farms) was found to have an association with yield. The surrounding natural areas likely act as a reservoir for both insects and their predators, which could be beneficial for the neighbouring agricultural lands by improving pollination, yield and nut quality through biological pest-control. Secondly, the Hazyview landscape composition was assessed, using National land-cover data and buffer zones around each of the five farms. Within a 5 km radius, land-cover composition varied across the five farms, reaching high proportions of natural vegetation (64.83 %), agriculture and forestry plantations (55.78 %), settlements (10.78 %) and water bodies (1.78 %) in some areas. This indicates the extent of the remaining natural vegetation surrounding each farm. Bat echolocation calls (bat activity) and insect collection (insect abundance) were conducted on two study farms. Sample points were located at different edge sites (land-use types), natural vegetation, river and road edges, to determine whether bats (activity) show preferences for foraging over macadamia orchards bordering natural vegetation and if insect abundance follows the same trend. Corresponding with other studies, land-use type, specifically natural vegetation bordering the farms, was significantly associated with increased bat activity and insect abundance within this agricultural landscape, with natural vegetation edges being preferred and road edges being least favoured by both. Bats from all three foraging guilds (clutter, clutter-edge and aerial) were recorded during the study, which indicates that the Hazyview farming region still appears to support a high bat species richness. In conclusion, this study highlights the importance of natural vegetation within an agricultural land-use mosaic and the benefits it can bring, both to the farmer and the surrounding biodiversity. Although ecosystem services were not directly measured, it can be deduced from the association of higher yield and better crop quality with surrounding natural vegetation, where the presence of bat and insects was found to be higher. Given the future increase in agricultural land expansion, information must be made publicly available, to allow farmers to consider all beneficial ecosystem services that the surrounding natural vegetation has to offer, namely pollination and pest-control. Farm management practices, which are aligned with consideration for ecosystem services have the potential to improve ecosystem functioning and service provision across agricultural landscapes. / Dissertation (MSc (Wildlife Management))--University of Pretoria, 2021. / Department of Science and Technology (DST), National Research Foundation (NRF) / Mammal Research Institute / MSc (Wildlife Management) / Unrestricted

No abstract provided. / Thesis / Bachelor of Arts (BA)

Daily temperature variations across an area can often be attributed to differences in land use/land cover (LULC). This study focuses on the relationships between the diurnal temperature ranges (DTRs) of 145 weather stations, classified as urban, agriculture, evergreen forests, deciduous forests, pine forests, and mixed forests. Paired samples t-tests were employed to test for significant DTR differences due to LULC type, season, and air mass type. Conflicting with previous research, agricultural areas reported the lowest DTRs, which may be due to the vegetation or to other physiographic variables. The forest types showed very few significant DTR differences. All of the LULC types experienced an annual bimodal DTR pattern, with peaks in April and October. Results of this study show that air mass has the largest influence on DTR (over LULC and season), therefore, the annual variability of air mass occurrence is most likely cause of the bimodal pattern.

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Stormwater retention ponds, constructed primarily for services such as flood control, are abundant in urban landscapes and documented hotspots of aquatic biodiversity. A previous study completed in our lab measured benthic community structure in several stormwater retention ponds in North Central Texas along an urban gradient. Results showed that larval chironomids (Diptera: Chironomidae) were the dominant macroinvertebrates in all of the ponds. It was also determined that differences in pond conditions associated with urban development could only be determined when chironomids were identified to the genus-level. However, collection and identification of chironomid larvae is often time-consuming. The objective of this current study is to evaluate the efficacy of the Chironomidae pupal exuviae technique (CPET) to detect changes in water quality in the same series of urban ponds in North Central Texas over one year. Based on results, CPET is an effective method of analyzing chironomid community response to environmental changes associated with anthropogenic impact. A total of 16,635 pupal exuviae were collected during this study representing 80 chironomid taxa, which included 40 genera across three subfamilies. The chironomid communities differed between ponds in proportion to the intensity of the urban development within their watersheds. Additionally, CPET provided the emergence phenology of a highly diverse chironomid assemblage. Results indicated that urban ponds in North Central Texas can provide refuge for biodiversity in a semi-arid region. As urbanization is projected to increase globally, it is critical to monitor how rapid urban expansion affects biodiversity and freshwater ecosystem conditions.

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