Master of Science / Department of Biology / Walter K. Dodds / North America has lost more than 95% of the original tallgrass prairie because of heavy land conversion, making prairie streams some of the most endangered habitats in North America. In order to effectively manage aquatic systems and improve biotic integrity of prairie streams research is needed that assesses the ecosystem characteristics of natural systems and evaluates the influence of anthropogenic alteration. We described the ecosystem characteristics of six ephemeral headwater streams draining tallgrass prairie within the Osage Plains of southwest Missouri. NO-3-N among all sites ranged from 1.56-91.36 μg L-1, NH+4-N ranged from 5.27-228.23 μg L-1, soluble reactive phosphorus ranged from below detection (1.0 μg L-1) to 41.22 μg L-1, TN ranged from 113.82-882.89 μg L-1, and TP ranged from 8.18-158.5 μg L-1during baseflow conditions. TN:TP molar ratios ranged from 22:1 to 53:1 indicating possible P was limiting relative to N in some streams. TSS during baseflow conditions ranged from 0.27-31.80 mg L-1. Autotrophic and heterotrophic comparisons of our study sites and reference sites classified our study streams as oligo-, meso-, and eu-autotrophic (N= 1, 4, and 1, respectively) and oligo-, meso-, and eu-heterotrophic (N= 4, 1, and 1, respectively). This study suggests that good water quality and moderate heterotrophic condition, with greater GPP resulting from an open canopy, are common conditions of tallgrass prairie streams. We also investigated interactions between land use/land cover, discharge rate, hydrologic alteration, and in-stream total suspended solids concentration in 23 Kansas- Missouri streams. Most streams had break points in the TSS loading rates at discharge rates exceeded <25% of days. Our estimates showed that 88% of the total annual TSS load occurred during the 11% of days with the greatest discharge rates. Buffered streams with greater percentages of grass and/or forest riparian areas had lower breakpoint values (indicating greater discharge rates were required to transport solid particles) and lower regression intercepts, which correlated to lesser TSS concentrations relative to unbuffered streams during high discharge days. In addition, grass buffered streams had smaller flood peaks and slower rise rates and forest buffered streams had less frequent floods, which lead to less total TSS transport.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: I investigated the impacts of the invasive wattle species (Acacia mearnsii, A. dealbata, A. decurrens), on the ecological function and productivity of rangelands in South Africa and their ability to sustain livestock production. More specifically, this study set out to: (1) assess grazing areas at a national scale; (2) identify evidence of progressive impacts of these species on livestock production across a selection of magisterial districts; (3) determine the effects of A. mearnsii density on growth form dominance of indigenous plant species, and highlight how this translates into impacts in forage quality and quantity; (4) determine the effects of A. mearnsii invasion on soil resources and conditions (key determinates of ecological function) required to support grazing production; and finally (5) determine to effects that clearing operations have had on the provision of grazing resources. My results indicate that the level of overlap between wattle invasion and areas with a high grazing potential, at the national scale, is relatively low (2.9%). However, at a magisterial district scale, areas with a high grazing potential have a moderate (approximately 35.1% high grazing potential area under wattle invasion for highest invaded district) level of invasion. Scattered and moderate levels of invasion currently dominate or characterise these species invasion patterns. Both light and dense A. mearnsii invasions reduce grazing capacity. Dense invasion had the most severe effect reducing grazing capacity from 2 ha, required to support one large stock unit, to 8 ha. The clearing of this species was found to improve grazing capacity within 5 years. The reduction in grazing capacity following invasion was largely due to reduced basal cover and herbaceous biomass. The clearing of invaded sites was found to increase both basal cover and herbaceous biomass to pre-invasion levels. Acacia mearnsii invasion was found to affect certain soil properties. Under an A. mearnsii canopy, plant litter, carbon content of the soil and nitrogen concentrations were all found to be elevated. Overall, this study demonstrates that Acacia invasions have a significant effect on grazing resources at a local or site scale, and that for the eastern region of South Africa, these effects are ultimately scaled up to a district level. This is likely to have important financial and human well-being repercussions. However clearing and restoration programs are clearly able to reverse or mitigate these effects. This study therefore lends support to or complements other ecosystem service provision arguments for clearing alien invasive species. / AFRIKAANSE OPSOMMING: Die impak van die indringer- wattelbome spesies ( A. mearnsii , A. dealbata , A. decurrens) , op die ekologiese funksie en produktiwiteit van weivelde in Suid-Afrika en hul vermoë om vee produksie te onderhou was ondersoek. Meer spesifiek, is hierdie studie uiteengesit om: (1) ondersoek in te stel na die mate van oorvleueling tussen indringing deur wattelbome spesies en belangrike weidingsgebiede op 'n nasionale skaal; (2) bewyse te verskaf van die progressiewe impak van hierdie spesies op vee-produksie oor 'n seleksie van politieke distrikte, (3) die gevolge van A. mearnsii digtheid op groei vorm en oorheersing van inheemse plante te wys, en hoe dit voer kwaliteit en kwantiteit affekteer; (4) die gevolge van A. mearnsii indringing op grond hulpbronne sowel as die kondisie (sleutel bepalende faktore van ekologiese funksie) wat benodig word om weiding produksie te ondersteun vas te stel, en uiteindelik (5) om die gevolge van skoonmaak bedrywighede op die voorsiening van weiding hulpbronne te bepaaal. My resultate dui daarop dat die vlak van oorvleueling tussen die wattelbome indringing en gebiede met 'n hoë weiding potensiaal, by die nasionale skaal, relatief laag is (2’9 %). Maar op 'n landdrosdistrik skaal, het gebiede met 'n hoë weiding potensiaal 'n matige (ongeveer 35.1 % weiding potensiaal area onder wattelbome indringing vir die hoogste binnegevalde distrik ) vlak van indringing. Verspreide en matige vlakke van indringing oorheers tans of kenmerk hierdie spesies se indringings patrone. Beide lig en digte A. mearnsii besettings verminder dravermoë. Digte inval het die mees ernstige uitwerking en verminder dravermoë van 2 ha, wat nodig is om een grootvee-eenheid te ondersteun na 8 ha. Bevindinge wys dat die verwydering van hierdie spesies weiding kapasiteit kan verbeter binne 'n tydperk van 5 jaar. Die afname in dravermoë na indringing is grootliks te wyte aan die afname in basale bedekking en kruidagtige biomassa. Na die skoonmaak van indringer persele is bevind dat beide basale bedekking en biomassa weer verhoog tot voor- indringings vlakke. Acacia mearnsii indringing beïnvloed sekere grondeienskappe. Onder A. mearnsii blaredak, is alle blaarafval, koolstof-inhoud van die grond en stikstof konsentrasies verhef. In die algeheel, toon hierdie studie dat die Acacia indringings 'n beduidende uitwerking op weidings hulpbronne by 'n plaaslike of perseel skaal het, en vir die oostelike streek van Suid-Afrika, is hierdie effekte ook uiteindelik vertaalbaar tot 'n distrik vlak. Dit sal waarskynlik belangrike finansiële en menslike welsyn gevolge hê, maar die skoonmaak en herstel programme is duidelik daartoe instaat om die gevolge te keer of te verminder. Hierdie studie leen dus ondersteuning aan of komplimenteer ander ekostelsel dienslewering argumente (soos dié van die Werk vir Water program) vir die verwydering van indringerspesies.

This study investigates the potential impacts on soils from development practices associated with new single-family residential home construction in the extra territorial jurisdiction (ETJ) of Pflugerville, Texas. My research question is: Are regulations that directly focus on soil conservation advisable within Pflugerville’s ETJ, and what areas of development ought to be primarily targeted by these regulations in order to better ensure the long-term stability of soil health and the minimization of soil loss? The rationale for this question is based on the city’s projected future population growth, the projected future demand for single-family residences, as well as the development and management practices typically associated with new single-family residential development in the ETJ of Pflugerville. I hypothesize that due to Pflugerville’s proximity to Austin and Round Rock, in addition to the relative abundance of available land to the east of the city of Pflugerville, that it is likely to continue experiencing sustained population and residential development growth, particularly in the form of new single-family residences in the ETJ. A population projection was conducted up to the year 2030, which in conjunction with average persons-per-household and single-family home permitting data, estimates potential consumer demand for single-family residences. The imperative to prevent soil loss is conceptually linked to ecosystem service benefits resulting from healthy and intact soils, such as improved water quality and the regulation of peak flow rates during storm events. Single-family residential development is evaluated in terms of conventional on-the-ground construction practices gathered from interviews with developers of single-family homes in the Pflugerville ETJ, as well as planning and regulatory specialists. These analyses are intended to inform regulatory and decision making processes regarding the importance and potential integration of soil preservation and conservation at the individual construction site level. / text

In this research, a recent version of the Boreal Ecosystem Productivity Simulator (BEPS), called BEPS-TerrainLab, was adapted to northern peatlands and evaluated using observations made at the Mer Bleue bog located near Ottawa, Ontario, and the Sandhill fen located near Prince Albert, Saskatchewan. The code was extended and modified with a major focus on the adequate representation of northern peatlands' multi-layer canopy and the associated processes related to energy, water vapour and carbon dioxide fluxes through remotely-sensed leaf area index (LAI) maps. An important prerequisite for the successful mapping of LAI based on remote sensing imagery is the accurate measurement of LAI in the field with a standard technique such as the LAI-2000 plant canopy analyzer. As part of this research, a quick and reliable method to determine shrub LAI with the LAI-2000 instrument was developed. This method was used to collect a large number of LAI data at the Mer Bleue bog for the development of a new remote sensing-based methodology using multiple endmember spectral unmixing that allows for separate tree and shrub LAI mapping in ombrotrophic peatlands. A slight modification of this methodology allows for its application to minerotrophic peatlands and their surrounding landscapes. These LAI maps were used to explicitly represent the tree and shrub layers of the Mer Bleue bog and the tree and shrub/sedge layers of the Sandill fen within BEPS-TerrainLab. The adapted version of BEPS-TerrainLab was used to investigate the in fluence of mescoscale topography (Mer Bleue bog) and macro- and mesoscale topography (Sandhill fen) on wetness, evapotranspiration, and gross primary productivity during the snow-free period of 2004. This research suggests that future peatland ecosystem modelling efforts at regional and continental scales should include a peatland type-specific differentiation of macro- and mesoscale topographic effects on hydrology, to allow for a more realistic simulation of peatlands' soil water balance. This is an important prerequisite for the reduction of currently existing uncertainties in wetlands' contribution to North America's carbon dioxide and methane annual fluxes from an ecosystem modelling perspective.

<p>In recent years, a global trend of increasing woody vegetation densities in semi-arid savanna habitats has been recorded, commonly described in South Africa as 'bush encroachment'. The shrubs and trees that do this (Increasers) have wrought significant economic and ecological impacts upon carrying capacities of large areas of savannas. This occurs, as suitable grazing areas are incrementally engulfed in shrubs and trees establishing new equilibria, from open savannas (essentially grasslands with scattered trees) into closed woodlands (treelands with scattered grasses). This thesis demonstrated a link between grass biomass, small mammal abundance and diversity, and their potential increaser seed/seedling predatory activities in the semi-arid Lowveld Savannas of South Africa.</p>

People visit protected areas (PAs) for enjoyment and appreciation of nature. However, tourism that is not well planned and managed can significantly degrade the environment, and impact negatively on nearby communities. Of further concern is the distribution of the costs and benefits of nature-based tourism (NBT) in PAs, with some communities experiencing proportionally more benefits, while other communities experience more of the cost. This distribution is complex and differs considerably amongst PAs. This thesis examines the flow and distribution of the costs and benefits of the NBT supply system to conservation and communities in the Serengeti ecosystem, Tanzania. The Serengeti ecosystem, a World Heritage site and a leading global wildlife tourism destination, was selected for this study because of high biodiversity, high poverty, and a high level of NBT activity. The research was guided by four main questions: (1) what is the nature of the supply system of NBT in the Serengeti ecosystem; (2) how do the management plans allow for and guide tourism in the Serengeti ecosystem; (3) what are the impacts of the NBT supply system on conservation; and, (4) what are the impacts of the NBT supply system on communities? A qualitative approach was used, combining document analysis, key informant interviews, and focus group discussions. This involved collecting data from a number of participants: PA agencies; the tourism industry; nearby communities; and non-governmental organizations. Participants were recruited through purposive and snowball sampling techniques. The findings offer an ecosystem-scale perspective rather than the common focus on a single PA. The study uses complex systems theory to help frame the NBT supply system in the Serengeti ecosystem, which is comprised of numerous agents that can be grouped in four major components − PAs, communities, tourism operations, and elements of the wider environment. The agents, such as tour operators, park management, and communities, vary across the ecosystem, and have multiple roles in NBT, including management of attractions, tourism planning and management, and provision of accommodation, transportation, accessibility, information, security, and utilities. There are complex interactions and relationships among these components across the ecosystem, and at local, regional, national, and international scales. PAs interact with tourism operators, PAs interact with communities, tourism operators interact with communities, and the three components are linked to the wider environment. These components of the NBT supply system interact dynamically in a non-linear manner, resulting in mixed outcomes for conservation and communities. The findings indicate the need for an integrated management approach to NBT in the Serengeti ecosystem that is more adaptive and ecosystem-based than currently exists. The wildlife legislation requires all PAs in the Serengeti ecosystem to have management plans, but some do not. The management plans in the ecosystem vary among PAs, with a number of flaws, including inadequate participation of stakeholders, poor use of zoning (design and implementation), and ineffective application of the “Limits of Acceptable Use” (LAU) as a main framework for controlling use. Management can be improved by several measures, including more effective inclusion of stakeholders, and application of the “Limits of Acceptable Change” (LAC) rather than “LAU,” amongst other measures that are outlined in more detail below. NBT in the Serengeti ecosystem is growing, and delivers a range of conservation benefits and costs that vary across the ecosystem. These conservation benefits include: financial support for conservation, improved biodiversity conservation and PA management, raised conservation awareness, and public support for conservation. These benefits can be improved by enhancing the quality of services and tourism experience, charging appropriate fees, PA agencies retaining a portion of tourism revenue, and improving collaboration and participation of stakeholders in NBT and conservation. Conservation costs include financial costs, wildlife disturbance, shifting priorities from conservation to tourism, habitat destruction, and pollution. These costs can be reduced by undertaking thorough investigation of the potential costs and benefits of tourism development, effective management planning, improving provision of information to tourists, and improving NBT management. NBT delivers many benefits to communities, such as income, employment, social services and infrastructure, scholarships, and school fees. These benefits can be improved by participation of local communities in conservation, promoting capacity building in local communities, improving legislation and mechanisms governing delivery of benefits, and encouraging communities to establish Wildlife Management Areas (WMAs). NBT results in many costs to local communities, such as loss of grazing land and farmland, conflict (tourism stakeholders, and human-wildlife conflicts), stress to local residents due to increase of human populations, and unintended consequences such as cultural degradation. These costs can be reduced by involving local communities in tourism development and management and developing codes of conduct for tourism operators and PA agencies. Specific examples of suggested actions include: developing and implementing effective management plans; promoting stakeholder awareness of conservation, NBT, and communities; and establishing a forum for discussing interests and issues of stakeholders in the ecosystem. The flow and distribution of these costs and benefits to conservation and communities also varies across the Serengeti ecosystem. Overall, NBT generates substantial benefits to PAs, although considerably less revenue is allocated to conservation activities than is accrued from NBT. On the other hand, local communities experience considerable costs and receive inadequate benefits that are not sufficient to address poverty. Inadequate mechanisms that govern the flow of the costs and benefits, poor governance, and persistent poverty are some of the main factors contributing to the imbalance of the flow and distribution of the costs and benefits of NBT. Finally, a complex systems perspective was shown to be a useful tool in understanding the NBT system as a whole, the dynamic interaction within the system and beyond, and associated costs and benefits delivered by that system. Overall, this study recommends adaptive management, ecosystem-based management, and an integrated approach that recognizes and accommodates the interests of various NBT stakeholders in the Serengeti ecosystem. Specific actions of high priority include developing and implementing effective management plans, adopting LAC in PA planning, capacity building for communities to participate in the tourism industry, and participation and collaboration of NBT stakeholders in the ecosystem. / Graduate

The Brenton Blue butterfly, Orachrysops niobe (Trimen) is currently only known to be extant at one locality in the southern Cape (the Brenton Blue Butterfly Reserve = BBBR), and currently globally Red Listed as "Critically Endangered". This research investigates the life history and ecological interactions of o. niobe and recommends management techniques for the BBBR. Adult nectar sources and female oviposition behaviour are described. The first two larval instars feed on the leaflets of the host plant Indigofera erecta Thunb., and the 3rd and 4th instar larvae feed on this plant's woody rootstock, attended by ants Camponotus baynei Arnold. Cannibalism takes place in the early larval stages. Adults emerge from late October - early December, from late January to early March, and occasionally there is a third brood in April. Morphological and behavioural features of the larvae are described, and larval growth patterns are compared to other polyommatines. The nature of the myrmecophilous behaviour is assessed and the phylogenetic relationships between Orachrysops, Euchrysops, Lepidochrysops, and other polyommatine genera are discussed. Ant assemblages at the BBBR are described from pitfall trap sampling and field observations of interactions between O. niobe larvae and ants. The ant assemblages at the BBBR, Nature's Valley Fynbos Reserve (NVFR) and Uitzicht 216/ 40 are compared. The potential impact of the Argentine ant at the BBBR is discussed. Adult and egg counts are used to study the population dynamics of O. niobe, leading to an estimate of the adult butterfly population and its fluctuations. A population dynamics model is constructed, and several factors impacting fecundity and mortality are assessed. Population studies on other polyommatines are compared and discussed. The morphology, reproductive biology and autoecology of the papilionoid legume I. erecta are described. An explanation is offered why the larvae of O. niobe are monophagous on this plant. Microhabitat variations cause changes in its vegetative morphology and this further explains the restricted range of O. niobe. The population dynamics of I. erecta is investigated and the effects of biotic and abiotic factors (including fire) assessed. Braun Blanquet methodology is used to sample and classify the vegetation communities at the BBBR. Ordination techniques are used to confirm the classification and to diagnose for environmental gradients. Hypotheses are generated about the ecological processes functioning at the site, and the environmental niche occupied by I. erecta. Correlations between the occurrence xxii of vegetation types and other plant species and I. erecta are sought and a strong association with Pterocelastrus tricuspidatus is demonstrated. Three study sites are described and the ecological history of the region is reconstructed. Ecosystems are no longer fully functional because natural fire regimes and megaherbivores are absent. It is suggested that O. niobe currently inhabits an interglacial refugium under stress from the current global warming trend. The remaining suitable habitat is threatened by coastal property development and environmental degradation. An increased population of o. niobe at the BBBR, and establishment of new populations is essential to avoid extinction. Management techniques are evaluated and a management strategy for the BBBR is proposed. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2006.

Land areas being used unsustainably are depleted and/or degraded. To prevent this from happening and/or to reverse the effects, we need to restore these environments. However, not all restoration practices are equal, and some do not adhere to rigorous standards of sustainability. In this study, restoration guidelines and opinions from field experts were analysed from an SSD perspective. The focus of this thesis was limestone quarries in northern Europe due to quarries’ impacts to the socio-ecological system and the sensitivity of northern ecosystems. The results were divided into two sub-sections: FSSD comparison to guidelines, which included an SP analysis to principles in guidelines, and interviews. The conclusion was that the SSD approach could enhance these quarry restoration guidelines by incorporating the recommendations formulated from the results and discussion. One recommendation was having the eight SPs as overarching boundaries for success. Incorporating these recommendations would fill the sustainability gaps, aiding in the practitioner's ability to be strategic and have long-term success within sustainable limits.

Previous work demonstrates conflicting evidence regarding the influence of snowmelt timing on forest net ecosystem exchange (NEE). Based on 15years of eddy covariance measurements in Colorado, years with earlier snowmelt exhibited less net carbon uptake during the snow ablation period, which is a period of high potential for productivity. Earlier snowmelt aligned with colder periods of the seasonal air temperature cycle relative to later snowmelt. We found that the colder ablation-period air temperatures during these early snowmelt years lead to reduced rates of daily NEE. Hence, earlier snowmelt associated with climate warming, counterintuitively, leads to colder atmospheric temperatures during the snow ablation period and concomitantly reduced rates of net carbon uptake. Using a multilinear-regression (R-2=0.79, P<0.001) relating snow ablation period mean air temperature and peak snow water equivalent (SWE) to ablation-period NEE, we predict that earlier snowmelt and decreased SWE may cause a 45% reduction in midcentury ablation-period net carbon uptake.

Throughout human history man has utilized the environment to varying degrees, depending on technology and population. These ¨ecosystem services¨ have suffered sustained degradation over the centuries, resulting in large investments having to be made to prevent and reverse further changes to the environment. Few studies have attempted to quantitatively compare how these changes, occurring long before modern environmental monitoring programs started, affected important ecosystem services such as species diversity, water quality, carbon burial and soil stability. The aims of this study were to i) assess whether human impact on ecosystem services have varied over time in perspective of relative change, and ii) to assess the individual (per capita) contributions. I used multiple sediment proxies from a 6 m C¹⁴-dated core collected from lake Ekoln, South-Central Sweden, to reconstruct environmental changes while tracking the population growth in the city of Uppsala during the last ten centuries. Through the use of pollen and diatom assemblages I reconstructed the changing terrestrial and aquatic diversities over time, while sediment accumulation rates and the X-ray fluorescence spectroscopy of the sediment was used to reconstruct soil stability, carbon burial and water quality, respectively. In the latter case, sediment phosphorus concentrations were used as a proxy for freshwater eutrophication while metals (mercury and lead) were used to infer inputs of toxic pollutants. Finally, I normalized (z) all data to create meta-data. The z-values and reconstructed population for Uppsala made it possible to differentiate 5 unique time periods based on anthropogenic induced change, which were not previously visible in the data, and all of which have been linked to the most likely historical causes, including the Black Death. The results show that the most significant anthropogenic impacts in terms of pollution volume occurred in the 1960s, while the period from 1200-1500 AD saw the most significant environmental change in terms per head of capita, most likely caused by the shift from woodland to open landscape through twiddening, a process of burning forest to create agricultural land, prior to 1500 AD. Moreover, rapid recovery is visible after the implementation of environmental policies from the 1970s onwards. / <p>Full surname: Kilpatrick van Houte</p>