<p>Livestock keeping has been the essential source of livelihood in Babati District for many hundreds of years. The traditional ecological knowledge about this semi-arid environment has influenced the general view on livestock management. This essay discusses the measures that are, or could be taken in Babati District to prevent overstocking and overgrazing in the woodlands. With the continuing population density increase also the livestock population grows. More houses and roads are built and the grazing lands diminish. To avoid overgrazing forest management programmes restrict grazing in forests. This additionally decreases availability of grazing land. My conclusion is that minimizing number of livestock is necessary to not exceed carrying capacity of pasture during drought. Hence this is not free from problems since it is traditionally rooted to have a large number of livestock as a buffer of energy and wealth. One solution for both how to prevent overstocking and how to survive with small number of livestock is to practise zero-grazing. Zero-grazing is to keep a small number of healthy big cattle e.g. exotic cows or crossbreeds in stables or tied up. However, when tying cattle on the spot the fact that cattle have four legs is disregarded.</p>

Cleaning validation of pharmaceutical manufacturing equipment is required by legislation. Generally, wet chemical techniques are employed using swabbing and/or rinse sampling methods. These are generally either selective and time consuming, or less selective and give results in a shorter period. The infrared reflection absorption spectroscopy (IRRAS) technique explored here attempts to deliver accurate, selective surface contamination information in real time to complement current methods and reduce down-time. The IRRAS instrument used in this research is a Fourier transform infrared (FTIR) spectrometer coupled by an IR fibre-optic cable to a grazing-angle sampling head with a fixed incidence angle of 80°. The introduced flexibility permits collection of in situ spectra from contaminated surfaces. Calibration models are developed using the multivariate, linear partial least squares (PLS) statistical method. The research focuses on sodium dodecyl sulfate (SDS), a model cleaning agent, on metal (aluminium and stainless steel) and dielectric (glass, EPDM and silicone) surfaces. The effects of surface finish are investigated for SDS on stainless steel. Calibrations for SDS and paracetamol in the presence of each other on glass surfaces are examined, as well as a common industrial cleaner (P3 cosa® PUR80) on polished stainless steel. For the calibration sets in this thesis, RMSECV values were < 0.41 µg cm⁻², corresponding to conservative surface residues detection limits of better than ~0.86 µg cm⁻². However, RMSECV values depend on the calibration loading range, and the detection limits were typically ~0.2 µg cm⁻² for loading ranges 0-2.5 µg cm⁻². These are below visual detection limits, generally taken to be 1-4 µg cm⁻², depending on the analyte and substrate. This shows that IRRAS is a viable method for the real-time detection and quantification of surface contamination by surfactants and active pharmaceutical ingredients on metals and dielectrics.

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14 pp. / A primary expression of stocking levels on rangeland vegetation is utilization defined as the proportion or degree of current years forage production that is consumed or destroyed by animals (including insects). Utilization may refer either to a single plant species, a group of species, or the vegetation as a whole. Utilization is an important factor in influencing changes in the soil, water, animal, and vegetation resources. The impact of a specific intensity of use on a plant species is highly variable depending on past and present use, period of use, duration of use, inter-specific competition, weather, availability of soil moisture for regrowth, and how these factors interact. Utilization data can be used as a guideline for moving livestock within an allotment with due consideration to season, weather conditions and the availability of forage and water in pastures scheduled for use during the same grazing season. In combination with actual use and climatic data, utilization measurements on key areas and utilization pattern mapping are useful for estimating proper stocking levels under current management. Utilization studies are helpful in identifying key and problem areas, and in identifying range improvements needed to improve livestock distribution.

Two trials were conducted to demonstrate diet selected by grazing cattle. Selection criteria were investigated on the basis of cattle selection for plant species, green leaf in preference to dry leaf or dry stem and the chemical contents of esophageal samples versus those in the standing crop. The influence of residual old vegetation on selection ability was studied by mowing all or part of the pasture. Cattle consumed Lehmann lovegrass in preference to shrubby species (Table 1). The esophageal samples contained higher levels of protein, phosphorus and IVDMD than that in the standing crop in both Trial 1 and Trial 2. Neutral detergent fiber was higher in the standing crop than in the esophageal samples, whereas in Trial 2, there appeared to be no difference in NDF. Removal of old vegetation by mowing had no effect on selection for plant parts. Cattle selected green leaf, in preference to dry leaf or dry stem regardless of the presence of old material. Free ranging cattle selected a diet that was higher in nutrient density and more digestible than the available forage.

Demographic, biological and behavioural knowledge, together with information on the ecological interactions and impact of a species is fundamental to effective management of most mammal species. In this study, these aspects were investigated for a population of feral horses in the Namib Naukluft Park of Namibia, which lies within a part of the Namib Desert. An attempt was made to evaluate the justification of the continued existence of this exotic species in a conservation area, as well as to provide baseline information and recommendations regarding management of these horses. The study investigated the botanical component and grazing capacity of the area inhabited by the horses, as well as the demography and quality of life of the horses. The study further examined the possible negative impact the horses may have on the natural biodiversity of the area. Finally, it looked at the historic, scientific, aesthetic and economic values of the horses. The collected data was then used as a technical basis for the development of a draft management plan during a stakeholder workshop. The study proposed a range of grazing capacity values related to the total rainfall of the preceding twelve months, based on grass production in response to rainfall in different plant communities. The horses, as well as the native large herbivores, utilized the study area according to the patchy rainfall patterns typically found in the Namib Desert. The population size of the horses fluctuated between 89 and 149 over a ten year period. The social structure of the population was more significantly influenced by artificial interference than natural disasters which had implications on natality, mortality and genetic viability. Termite activity, measured as utilization of grass provided in bait boxes, did not correlate with horse density and seems, instead, to be influenced by soil properties. The results of ant and tenebrionid beetle species composition surveys and analyses did not indicate a significant negative impact from the horses on the study area. No indication could be found that the horses threaten the survival of any native species in the area or that they change the vegetation structure. It appears as if the biodiversity of the area is subjected to large natural stresses due to the continued and frequent desiccation in the desert environment. The impact of the horses is therefore probably minor to that of the climatic stochasticity. It also became apparent that the horses have developed significant historical, scientific and tourism value. The general public opinion is that the horses should be managed as a wild population with minimal artificial interference. / Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2006.

This thesis investigates the effects of rangeland management systems on savanna ecosystems under different environmental conditions in Botswana, Southern Africa. The soil sampling and vegetation assessment were conducted in twenty–three transects located in communal and ranching grazing lands across three sites. Pastoralists were also interviewed on vegetation change on their respective grazing lands. Soil texture, pH, bulk density and soil organic carbon differed between sites, but not between communal and ranching lands. Soil organic carbon was positively affected by soil clay content. The herbaceous vegetation composition showed heterogeneity between sites, but Matlolakgang and Xanagas rangelands were in poor condition, particularly the communal grazing land that had high cover of increasers II species. Higher herbaceous biomass was observed in ranches than communal lands and biomass also increased with increasing soil organic carbon. Bush encroachment was observed in communal and ranching grazing lands at Matlolakgang and Xanagas, but not Goodhope. Woody plant cover, density and diversity increased with decline in soil clay content, but not linearly. Pastoralists indicated that herbaceous vegetation compositions had changed in some areas, with increase of unpalatable grass species and bush encroachment especially in communal land. Pastoralists considered bush encroachment a problem as it suppress herbaceous vegetation productivity, but they also considered woody vegetation as a valuable grazing resource. The long-term indicators of ecosystem degradation (soil and woody cover) showed that communal and ranching grazing did not affect the savanna ecosystem differently. This is contrary to assumptions of Tribal Grazing Land Policy of Botswana, which promote ranching as a more sustainable management system. The results revealed that rainfall and soil clay strongly influence rangeland condition. These results have implications for the management policies of communal grazing lands throughout sub-Saharan Africa and in similar arid habitats across the world.

Tropical coral reefs are among the most diverse ecosystems of the world but facing increasing threats to their health. Over the last thirty years, many Caribbean coral reefs have undergone dramatic changes and experienced large losses in coral cover, due to direct and indirect anthropogenic disturbances. The results of which are reefs with low rugosity, changed trophic dynamics and low fish diversity. In recent times reefs have failed to recover from disturbances due to an increase in frequency and severity of disturbances and stresses. In the Caribbean on many coral reefs this has resulted in a shift towards macroalgal dominance by species of the phylum Phaeophyta. The processes and factors affecting the standing crop of macroalgae are many and complex. Two main hypotheses are identified in the literature as being the driving forces of algal dynamics: nutrient dynamics (availability, supply and uptake) and herbivory. However, many studies have been found to be inconclusive because of the complexity of the coral reef ecosystem, which makes it difficult if not impossible to control for all factors and processes influencing the standing crop of macroalgae such as light, water flow and sedimentation. The inherent characteristics of macroalgae, like morphology and life history, make them behave differently. Whilst herbivore characteristics, like size of mouth parts, feeding modes and preferences, will influence the amount of algal biomass removed. The spatial context (i.e. coral fore reef vs. back reef) will influence the effects of both bottom-up and top-down controls. Besides these inter-habitat differences, macroalgae within similar habitats but differing geographical locations may respond differently, for example, a forereef exposed to the open ocean or a forereef located in a sheltered bay. This thesis attempts to provide insight into the dynamics of two dominant brown macroalgae on Caribbean coral reefs, Dictyota spp. and Lobophora variegata. This aim was addressed by developing a model for the macroalga species Dictyota to model the various processes and factors on a coral forereef affecting percentage cover. Further, the patch dynamics of both Lobophora variegata and Dictyota were investigated to gain an insight into their dynamics under varying environmental conditions: the windward and leeward sides of an atoll. Finally, herbivory is identified as one of the key process affecting macroalgal cover. I investigated this process by deploying cages on both the windward and leeward side of the atoll to investigate the effects of grazing pressure under varying environmental conditions. A Bayesian Belief Network model was developed for Dictyota spp. to model the bottom-up and top-down processes on a coral forereef determining the percentage cover. The model was quantified using relationships identified in the scientific literature and from field data collected over a nine moth period in Belize. This is the first BBN model developed for brown macroalgae. The fully parameterized model identified areas of limited knowledge and because of its probabilistic nature it can explicitly communicate the uncertainties associated with the processes and interactions on standing crop. As such the model may be used as a framework for scientific research or monitoring programmes and it is expected that the model performance to predict macroalgal percentage cover will improve once new information becomes available. Size-based transition matrices were developed for both Dictyota spp. and Lobophora variegata to investigate the patch dynamics under varying environmental conditions: the windward and leeward sides of an atoll. The matrices reveal that standard measures of algal percent cover might provide a misleading insight into the underlying dynamics of the species. Modelling the patch dynamics with matrices provided insight into the temporal behaviour of macroalgae. This is an important process to understand because patch dynamics are determining competitive interactions with other coral reef benthic organisms. The outcome of competitive interactions will differ with macroalgal species. This study indicate that Dictyota spp. responded strongly to differing environmental conditions in that it has reduced growth rates and lower percent cover on the leeward side of the atoll, whilst Lobophora variegata showed far less sensitivity to environmental conditions. The patch dynamics of Dictyota spp. also showed a higher temporal variation than Lobophora variegata but only on the exposed forereef. A caging experiment was set up to investigate the response of both macroalgal species to different grazing pressure scenarios, under varying environmental conditions. Dictyota spp. had a significant response to environmental conditions in that a higher percentage cover was found on the exposed side of the atoll, whilst for Lobophora variegata the response was far less obvious. The less clear response of Lobophora variegata was very likely caused by competition of Dictyota with Lobophora due to the very high cover Dictyota obtained in the cages where all herbivores were excluded. The low grazing pressure treatments also showed an increase in cover of Dictyota, whilst for Lobophora, only a reduction in the rate of increase could be observed. The results indicate that on the leeward side of the atoll, fish grazing alone seems sufficient to control the standing crop of Dictyota and Lobophora variegata. Retrospective analysis of the experimental design showed that the limited size of the experimental set up could have confounded the results for Lobophora as well. In future experiments it is recommended to increase number replicates. Management of coral reef habitats is frequently constrained by a lack of funds and resources. The BBN Model once fully parameterized can provide a useful tool for coral reef management, because the model allows exploration of different reef scenario’s, which in turn can aid in prioritizing management strategies. Furthermore, the thesis provided an insight into the complexities of macroalgal dynamics. The responses of macroalgae to physiological factors and ecological processes are species specific and dependent on the location, and caution against generalizing on what controls the standing crop of macroalgae. Therefore it is argued that future investigations into algal ecology should clearly define the species, habitat and location. This can help to make informed management decisions.

In this study we determined the magnitude of plant mediated CH4 emission (flux) in two vegetation types of Carex ramenskii. The objectives of this paper were to quantify the proportion of CH4 emissions from plant mediated flux and the total flux (plant and soil). This information is needed in order to understand how grazing affects plant mediated CH4 flux. In addition, we differentiated between two vegetation morphs, grazed and ungrazed, and determined the plant mediated CH4 flux for vegetation type.  This study was conducted at a field site on the Tutakoke River (61 15’N, 165 30’W) which is located in the coastal region of the Yukon-Kuskokwim Delta. Three replicate plots of the two vegetation morphs of Carex ramenskii were established. Methane flux was measured with a total flux chamber (plant and soil) and a single leaf chamber using a Picarro Cavity Ring-Down Spectroscopy Analyzer (Model G2308, Picarro Inc., Santa Clara, California). Plant density for the two plant types was determined. Temperature measurements were taken and correlated with gas flux. This study found that total net CH4 emissions from Carex ssp. were the same in both vegetation types. This similarity could indicate that plant mediated flux through vegetation is not affected by grazing in the sense that grazing is neither facilitating nor inhibiting plant mediated CH4 flux. The magnitude of plant mediated flux was still greater in the ungrazed meadow type, indicating on both greater facilitation of CH4 flux, and below ground oxygen transport enabling higher rates of CH4 consumption.

The Swedish village by-laws are a collection of rules for coexistence in a village which evolved during the 18th and 19th centuries. The dissertation takes its starting point in an edition of Byordningar från Mälarlänen (Village By-Laws in the Lake Mälar districts) containing about 400 by-laws from the central part of Sweden, and is a limited review of that edition at the same time as it gives a systematic survey of certain aspects specified in the by-laws. These aspects were added as the result of an official proposal in 1742 containing a model on how a by-law should be constructed. The question is asked whether the directives of the Government were formulated when they reached the local level, or whether they were redesigned and adapted to suit the local situation. The village by-laws in the Mälar counties differ in form and in content depending upon the official proposal on by-laws from 1742. The village by-laws were originally discussed in connection with the changes in agriculture, and thus concerned such sectors as farming methods, fencing, grazing, the right to certain proportions of the village's resources. The local conditions in the village are reflected in, for example, the rules on the length of the grass for grazing. There were different kinds of such by-laws, e.g., by-laws for individual villages and by-laws for parishes (approved at a parish meeting). The initiative of the Government in requiring village by-laws gave different results in different counties. Large parts of Uppsala county are without forest land. The fences and the system of enclosing fields are therefore of particular interest in a discussion on the village by-laws. I have demonstrated that their origin and acceptance in Swedish villages and parishes can be placed in political, chronological, social and functional contexts. / <p>Diss. Uppsala : Univ.</p>