The Little Bow River Project was implemented in 2003 and includes Alberta’s newest dam. The Project involves tripling the diversion of water from the Highwood River to the Little Bow River and subsequently storing the water in the Twin Valley Reservoir. This MSc Thesis provided part of the environmental monitoring for that Project and particularly investigated the impacts of augmented flows on the river channel and riparian vegetation along the upper reach of the Little Bow River. An initial component of the long-term study was to determine the existing associations between fluvial geomorphic characteristics and riparian plant communities. Poplar (Populus balsamifera L.), willow (Salix bebbiana Sargent and S. exigua Nutt.) and wolf-willow (Elaeagnus commutata Bernh.) communities were located along the upper section of the river, where the channel had a steeper gradient and was narrower and more sinuous. Cattail (Typha latifolia L.) and grass (grasses and sedges) communities were generally located along the lower section of the river that was shallower in gradient, wider and straighter. Plant community distribution also reflected impacts from cattle grazing. Initial channel and vegetation responses in the first two years following the increase in flow augmentation were slight and included bank slumping, sediment scour and inundation of flooded zones. The initial responses are consistent with the primary prediction of channel widening and this will probably be associated with some changes in the adjacent riparian plant communities. / xiv, 139 leaves : ill. (some col.) ; 29 cm.

Conventional wisdom in ecotoxicology predicts reductions in organismal fitness to follow from exposure-related physiological effects. This expectation may be appropriate for controlled laboratory environments, but may not necessarily reflect what is likely to take place in the wild. In an extensive review of the ecotoxicology literature, it was revealed that fish condition factor (an index of energetic fitness) is just as likely to respond favourably to pollutant exposure as it is to respond negatively. The remainder of this thesis examines some of the ecological reasons for this apparent paradox. One possible cause of altered energetic status in wild, pollutant-exposed fish is variable food availability. Addressing this possibility, I showed that consumption rates (estimated using a 137Cesium mass-balance approach) were not related to growth reductions in hormonally-impaired yellow perch ( Perca flavescens) from metal-contaminated lakes. Another possibility is that fish forage less efficiently in metal-polluted lakes as a result of lowered prey choice. In this thesis, I develop an enzymatic and individual-based biomarker for fish activity costs (muscle lactate dehydrogenase, LDH, activity) and show, through the use of this tool that the cost of fish activity is intimately tied to prey type and the ability to make normal ontogenetic diet shifts. Through the application of LDH measurements, as well as through bioenergetic modelling, diet and prey community analyses, a link between decreased prey choice and high perch activity costs leading to zero growth efficiency (energetic bottlenecks) was demonstrated in yellow perch from metal-contaminated lakes. This finding provided one of the first examples in ecotoxicology of a mechanistic link between community and organismal endpoints. The findings of this thesis emphasize the need for ecotoxicology to consider ecology when looking for and interpreting ecologically relevant endpoints. The final chapter of this thesis ex

Sorghum breeders have not made much yield improvement in new sorghum varieties in Kenya since Serena in was released in the late 1960s. KARI Mtama-1 which was released in 1993 has no yield advantage over Serena. A yield plateau for sorghum in Kenya is apparent. A new breeding approach was adopted to break that yield barrier. Development of hybrid sorghum was proposed and is expected to break the yield barrier and also deliver cultivars that meet farmers' main requirements. The objectives of the study were to (1) identify farmers' requirements in sorghum cultivars, constraints to sorghum production and why improved cultivars from research are not being adopted, (2) characterize male and female parents and establish if genetic distance could identify superior parent populations for hybrid production (3) estimate genetic variance components and determine the possibility of using GCA and SCA estimates in choosing parents for use in hybrid production, (4) test hybrids and open pollinated variety (OPV) parental lines for stress tolerance and identify tolerant hybrids for further testing and, (5) compare single cross hybrids and OPV varieties in yield performance. Participatory rural appraisal in Kitengei and Nzambani areas of Kambu showed that sorghum was especially important in semi-arid parts of Kenya. Food, trade, feed, nursing food and thatching were the most important uses of sorghum. High grain and stover yield, large grain size, early maturity, drought tolerance, pest and disease resistance, coloured grain and intermediate plant height were the major requirements of farmers. Fifty-three pollinators and forty-one male sterile parents were introduced from four sources and screened together with 27 pollen parents from Kenya. Parents and hybrids were tested in 4 environments: high and low plant density, in high and low moisture regimes laid out in a triple square lattice design in Kenya, with parents having two additional tests in South Africa. Males, females, sexes and parental sources differed significantly in head weight. There were sex x country and sex x environment interactions for head weight. Genetically distant parents' populations had higher chances of superior heterosis. Parents showed significant additive genetic variance in head weight. The regression of non-additive to additive genetic variance was roughly one and significant. Three female and five male parents were suitable for production of hybrids adapted to multiple environments. Hybrids and OPV lines significantly varied in head weight. Hybrids were superior to OPV lines in most agronomic traits. Economic superiority of the hybrids was sufficient to cover cost of hybrid production and distribution in Kenya. Hybrids and OPV lines varied significantly for plant density stress. Hybrids were less sensitive to stress and more productive than OPV lines under population density stress. KARI varieties were sensitive to plant density stress. In general low sensitivity to stress was beneficial and hybrids had superior yield to inbred varieties. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

The measurement of plant water content is essential to assess stress and disturbance in forest plantations. Traditional techniques to assess plant water content are costly, time consuming and spatially restrictive. Remote sensing techniques offer the alternative of a non destructive and instantaneous method of assessing plant water content over large spatial scales where ground measurements would be impossible on a regular basis. The aim of this research was to assess the relationship between plant water content and reflectance data in Eucalyptus grandis forest stands in KwaZulu-Natal, South Africa. Field reflectance and first derivative reflectance data were correlated with plant water content. The first derivative reflectance performed better than the field reflectance data in estimating plant water content with high correlations in the visible and mid-infrared portions of the electromagnetic spectrum. Several reflectance indices were also tested to evaluate their effectiveness in estimating plant water content and were compared to the red edge position. The red edge position calculated from the first derivative reflectance and from the linear four-point interpolation method performed better than all the water indices tested. It was therefore concluded that the red edge position can be used in association with other water indices as a stable spectral parameter to estimate plant water content on hyperspectral data. The South African satellite SumbandilaSat is due for launch in the near future and it is essential to test the utility of this satellite in estimating plant water content, a study which has not been done before. The field reflectance data from this study was resampled to the SumbandilaSat band settings and was put into a neural network to test its potential in estimating plant water content. The integrated approach involving neural networks and the resampled field spectral data successfully predicted plant water content with a correlation coefficient of 0.74 and a root mean square error (RMSE) of 1.41 on an independent test dataset outperforming the traditional multiple regression method of estimation. The potential of the SumbandilaSat wavebands to estimate plant water content was tested using a sensitivity analysis. The results from the sensitivity analysis indicated that the xanthophyll, blue and near infrared wavebands are the three most important wavebands used by the neural network in estimating plant water content. It was therefore concluded that these three bands of the SumbandilaSat are essential for plant water estimation. In general this study showed the potential of up-scaling field spectral data to the SumbandilaSat, the second South African satellite scheduled for launch in the near future. / Thesis (M.Sc.) - University of KwaZulu-Natal, Pietermaritzburg, 2008.

Metal contamination can disrupt the trophic links in food webs by altering the taxonomic composition and size structure of benthic invertebrate communities. Benthic invertebrate samples and perch (Perca flavescens) were collected from six lakes along a gradient of metal pollution in Rouyn-Noranda, Canada. The benthic communities of the contaminated lakes were less diverse and had smaller individuals (0.09 mg d.w. and 0.16 mg d.w. vs. 0.22 mg d.w. in the reference lake). The stomach contents of perch from contaminated lakes were less diverse, showed a greater reliance on chironomids or zooplankton, and cannibalism than perch from less polluted lakes. The mean size of prey in perch from contaminated lakes was smaller than in reference lakes (3.7 mg d.w. and 7.39 mg d.w. vs. 47.7 mg d.w. and 67.1 mg d.w. in reference lakes). (Abstract shortened by UMI.)

[Truncated abstract] In southern Australian farming systems the replacement of deep-rooted perennial native vegetation with shallow-rooted annual crops and pastures has resulted in rising groundwater tables and an increased incidence of dryland salinity. It has been suggested that to address this issue by restoring hydrological balance, large areas of agricultural land need to be vegetated with perennial plants. One of the most agriculturally productive ways to do this is to introduce perennial pastures, both into upslope groundwater

A growing human population accompanied by urbanisation and industrialisation have led to over exploitation and pollution of freshwater resources and have consequently impacted on aquatic ecosystem health. The Swartkops River in the Eastern Cape of South Africa is no exception. It drains a heavily industrialised catchment which has led to deterioration of its water quality due to pollution. Integrated water resources management (IWRM) requires the concurrent sustainable use of water resources and the protection of aquatic ecosystem health. Macroinvertebrates are well known for their ability to reflect the health of the environment in which they live, thus they were used to assess anthropogenic impacts in the Swartkops River for this study. Macroinvertebrate based biomonitoring approaches, including the South African Scoring System version 5 (SASS5); a multimetric approach involving 19 metrics; Chironomidae community assessments and screening of morphological deformities in Chironomidae larvae, were applied at four selected sampling sites to assess environmental water quality in the Swartkops River. Macroinvertebrates were sampled us ing the SASS5 protocols. Chironomidae were mounted and identified as far as practically possible using available keys. Mentum, ligula, mandible, paraligula and antenna in Chironomidae larvae were screened for deformities. Physical and chemical water quality variables were measured at each of the selected sampling sites. All data were subjected to relevant statistical analyses. Of the four sites sampled during the study period, results revealed that water quality at site 1 was the least impacted with highest SASS5 scores, average score per taxa (ASPT) values, richness, diversity, equitability and Ephemeroptera –Plecoptera-Trichoptera (EPT) richness, as well as least incidences of chironomid deformities. Water quality at site 2 was considered the next least impacted with higher SASS5 scores, A SPT values, richness, diversity and equitability, and lower incidences of deformities compared to sites 3 and 4. SASS5 scores and ASPT values revealed that both sites 3 and 4 were critically modified but the multimetric analysis, Chironomidae community assessment and incidences of deformities in Chironomidae larvae indicated that site 3 is the most impacted of the four sampling sites, with least species diversity, richness, equitability and highest incidences of deformities. The study revealed the importance of multicriteria approach to environmental biomonitoring as an integrated water resources management tool, and based on the results, site 3, as the most impacted, could be prioritised for restoration intervention.

Ph.D. / The Crocodile River catchment, in Mpumalanga, is one the most intensively used catchments in South Africa. The large number of intensively cultivated crops grown in the middle and lower subcatchments; industrial discharges; highly intensive irrigation; and extensive areas of exotic afforestation in the upper and middle sub-catchments has dramatically changed land use patterns within the catchment. The Middle Crocodile River sub-catchment is also impacted by intensive urbanisation; around Nelspruit, KaNyamazane and Matsulu. The Kaap River sub-catchment has been intensively mined for minerals and the impacts of these mining operations are still reflected in the water quality of streams and rivers in this sub-catchment. The downstream uses of the Crocodile River's water quality are the aquatic ecosystem, the Kruger National Park (as the river is the southern boundary of the park) and Mozambique (international obligations). The Crocodile River catchment supports one of the richest fish species diversities in South Africa. It is therefore important to determine the impacts of these land use activities on the fish populations and the potential human health risks if fish are consumed. In the present study data from five gauging stations for each of the main tributaries draining the five sub-catchments (the Upper, Middle and Lower Crocodile River, Kaap and Elands Rivers) were used. The water quality and quantity was determined from Department of Water Affairs and Forestry's (DWAF) National Hydrological Chemical Data Bank. Assessments of water quality (chemical, physical), sediment characteristics, and fish biological characteristics were undertaken at each of the chosen sampling sites. Water and fish samples were collected seasonally on ten sampling trips during the study period, June 1989 to September 1992. Eleven species of fish were collected, by means of gill and seine nets, at eight sites. The biological characteristics of the larger fish captured were measured and tissue (gills, liver, muscle, intestine, ovaries, testes and abdominal fat) samples were collected. These samples were analysed for eleven metals and Pyrethroid, Carbamate, Organochlorine, Organophosphate and Triazine pesticides. Sediment core samples were collected and determinations made of particle size, percentage organics, metals and pesticides. Standard methods were used for the determination of .the metal and pesticide concentrations in the water, sediment and fish tissues. The pesticide use per crop for South Africa was determined from a data-base. This data was used to determine the potential pesticide runoff from the different crops in the sub-catchments and to compare with the sediment and fish tissue levels recorded. The water quality status of the Crocodile River catchment is impacted by a variety of diffuse and point sources of pollution. The water quality indicated that diffuse sources of pollution originated from afforestation in the Upper, Middle and Kaap River sub-catchments; current and abandoned mining activities in the Kaap River sub-catchment; runoff from irrigated lands in the Middle, Lower and Kaap River sub-catchments; and wastes from industrial activities in the Elands and Middle sub-catchments. Point sources of pollution in the Crocodile River include ndustrial and waste water treatment works discharges mainly in the Middle sub-catchment.

Anthropogenic carbon dioxide (CO2) emissions are increasing the atmospheric CO2 concentration and the oceans are absorbing around 1/3 them. The CO2 hydrolysis increases the H+ concentration, decreasing the pH, while the proportions of the HCO3- and CO32- ions are also affected. This process already led to a decrease of 0.1 pH units in surface seawater. According to "business-as-usual" models, provided by the Intergovernmental Panel on Climate Change (IPCC), the pH is expected to decrease 0.3-0.5 units by 2100 and 0.7-0.8 by 2300. As a result the surface ocean carbonates chemistry will also change: with increasing pCO2, dissolved inorganic carbon will increase and the equilibrium of the carbonate system will shift to higher CO2 and HCO3– levels, while CO32– concentration will decrease. Surface seawaters will progressively become less saturated towards calcite and aragonite saturation state and some particular polar and cold water regions could even become completely undersaturated within the next 50 years. <p>Responses of marine organisms to environmental hypercapnia, i.e. to an excess of CO2 in the aquatic environment, can be extremely variable and the degree of sensitivity varies between species and life stages. Sea urchins are key stone species in many marine ecosystems. They are considered to be particularly vulnerable to ocean acidification effects not only due to the nature of their skeleton (magnesium calcite) whose solubility is similar or higher than that of aragonite, but also because they lack an efficient ion regulatory machinery, being therefore considered poor acid-base regulators. Populations from polar regions are expected to be at an even higher risk since the carbonate chemical changes in surface ocean waters are happening there at a faster rate. <p>The goal of this work was to study the effects of low seawater pH exposure of different life stages of sea urchins, in order to better understand how species from different environments and/or geographic origins would respond and if there would be scope for possible adaptation and/or acclimatization.<p>In a first stage we investigated the effects of ocean acidification on the early stages of an intertidal species from temperate regions, the Atlantic Paracentrotus lividus sea urchin, and of a sub-Antarctic species, Arbacia dufresnei. The fertilization, larval development and larval growth were studied on specimens submitted through different pH experimental treatments. The fertilization rate of P. lividus gametes whose progenitors came from a tide pool with high pH decrease was significantly higher, indicating a possible acclimatization or adaptation of gametes to pH stress. Larval size in both species decreased significantly in low pH treatments. However, smaller A. dufresnei echinoplutei were isometric to those of control treatments, showing that size reduction was most likely due to a slower growth rate. In the pH 7.4 (predicted for 2300) treatment, P. lividus presented significantly more abnormal forms than control ones, but A. dufresnei did not. The latter does not seem to be more vulnerable than temperate species, most likely due to acclimatization/adaptation to lower pH seasonal fluctuations experienced by individuals of this population during spring time.<p>In a second stage, adult physiological responses of P. lividus and A. dufresnei to low pH seawaters were studied. Intertidal field P. lividus specimens can experience pH fluctuations of 0.4 units during low tidal cycles, but their coelomic fluid pH will not change. During experimental exposure to low pH, the coelomic fluid (extracellular) pH of both species decreased after weeks of exposure to low seawater pH. However, it owned a certain buffer capacity (higher than that of seawater) which did not seem to be related to passive skeleton dissolution. In laboratory studies, the feeding rate of P. lividus, the RNA/DNA ratio (proxy for protein synthesis and thus metabolism) of both the gonads and the body wall of the studied species and the carbonic anhydrase activity in the body wall (an enzyme involved in calcification and respiratory processes) of A. dufresnei did not differ according to seawater pH. The same was true for spine regeneration (a proxy for calcification) of both species. This shows that both P. lividus and A. dufresnei are able to cope when exposed to mild hypercapnia (lowest investigated pH 7.4) for a mid-term period of time (weeks). In a different set of experiments, pH effects were tested on P. lividus individuals together with two temperatures (10ºC and 16ºC). The pH decrease of the coelomic fluid did not vary between temperatures, neither did its buffer response. The oxygen uptake rates of P. lividus (as a proxy for global metabolic state of the whole organism) increased in lower pH treatments (7.7 and 7.4) in organisms exposed to lower temperatures (10ºC), showing that this was upregulated and that organisms experienced a higher energetic demand to maintain normal physiological functions. For instance, gonad production (given by the RNA/DNA ratio) was not affected neither by temperature, nor pH.<p>Finally, possible morphological and chemical adaptations of cidaroid (“naked”) spines, which are not covered by epidermis, to low magnesium calcite saturation states were investigated. Deep sea field specimens from the Weddell Sea (Antarctica), Ctenocidaris speciosa were studied. Cidaroid spines have an exterior skeleton layer with a polycrystalline constitution that apparently protects the interior part of the monocrystaline skeleton, the stereom (tridimensional magnesium calcite lattice). The cortex of C. speciosa was by its turn divided into two layers. From these, it presented a thicker inner cortex layer and a lower Mg content in specimens collected below the aragonite saturation horizon. The naked cortex seems able to resist to low calcium carbonate saturation state. We suggest that this could be linked to the important organic matrix that surrounds the crystallites of the cortex.<p>Some echinoid species present adaptive features that enable them to deal with low pH stresses. This seems to be related to the environmental conditions to which populations are submitted to. Therefore, organisms already submitted to pH daily or seasonal fluctuations or living in environments undersaturated in calcium carbonate seem to be able to cope with environmental conditions expected in an acidified ocean. Under the realistic scenario of a decrease of ca. 0.4 units of pH by 2100, sea urchins, and echinoderms in general, appear to be robust for most studied processes. Even thought, this general response can depend on different parameters such as exposure time, pH level tested, the process and the life stage considered, our results show that there is scope for echinoids to cope with ocean acidification.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

M.Sc. (Zoology) / The Vaal River system is constantly subjected to pollution from various industrial, mining and agricultural activities. Consequently, pressure is continually exerted on the health of its fish communities and it was suspected that this may be a contributing factor to the repeated fish kills that have occurred in various sections of the river over the past few years. The aim of this study was to assess the health status of three fish species that were affected by the most recent mass fish mortality in the Vaal River. This was done using a combination of techniques including a histology-based health assessment (HHA) that involved a standard fish necropsy, the evaluation of blood parameters as well as a microscopic assessment of the liver, kidney, gills, and gonads. The histological results were semi-quantitatively assessed. Selected chemical substances were also tested for in water, sediment and the skeletal muscle tissue of the fish. Clarias gariepinus, Labeo capensis and Labeo umbratus specimens were collected from the Vaal River, approximately 2480m below the Vaal Dam (Latitude 26°51'17.47"S; Longitude 28° 7'16.58"E) following the latest occurrence of a fish kill in November 2011. Fish were collected using gill nets. Water was sampled in triplicate at three locations, and in situ measurements were done for selected physico-chemical parameters. Sediment samples were also collected and subjected to a sequential extraction technique and quantification of the heavy metals was done using Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS). Metals in skeletal muscle tissue and water were quantified using the same technique. An analysis of variance (ANOVA), followed by the appropriate post-hoc test was performed to determine differences between means of variables i.e. morphometric, histological, substance concentration and blood parameters...