Thèses sur le sujet « Rider Behaviour »

This thesis consists of eight chapters describing the development and validation of the Equine Behavior Assessment and Research Questionnaire (E-BARQ). The E-BARQ, a novel citizen science project, has the potential to change the way we understand horse behaviour by investigating the domestic equine triad of training, management and behaviour and linking its various interactions to outcomes and interventions. The way that horses are trained, handled, and managed influences their behaviour that, in turn, impacts both rider safety and horse welfare. While the fields of equine science and equitation science have made inroads into our understanding of horse behaviour, many traditional management and training techniques continue to be used today, despite the lack of an evidence-base to substantiate their efficacy. To obtain a baseline understanding of what constitutes normal behaviour in horses, it is necessary to collect, analyse and interpret large-scale, longitudinal, observational data relating to what I have dubbed the domestic equine triad. These data will reveal how our current training and management practices affect behaviour, a knowledge gap that could be argued to have, until now, compromised rider safety and horse welfare. The E-BARQ is designed to bridge this gap, deepen our understanding of horse behaviour and the horse-human dyad, and provide a robust, One Welfare evidence-base for future equine research promoting ethical equitation.

Thesis (M.S.)--University of Kentucky, 2008.
Title from document title page (viewed on February 3, 2009). Document formatted into pages; contains: viii, 72 p. : ill. (some col.), maps (some col.). Includes abstract and vita. Includes bibliographical references (p. 69-71).

The purpose of this travel cost study is to determine how rider behaviors and site characteristics influence repeat visits for equestrian trail riding in Kentucky. Primary data was collected via a survey developed and administered to trail riders in person and online. The average surveyed trail rider tends to be female, about 46 years old, with some higher education, and an annual household income of $65,000. She makes 11 trips to a specified site per year, 8 of which are daytrips, usually in the fall, and traveling 132 miles round trip. From other information gathered, an index of trail characteristics was developed to identify positive attributes of trails. To account for overdispersion of the number of visits per year, a negative binomial distribution in the estimation was used. The primary variables significant to explaining repeat visits to a site include distance in miles, the index of characteristics, and gender. Given consumer surplus estimates of $800 per equestrian it is recommended that established trails maximize desired characteristics. For new trail development it is recommended that trail characteristics are maximized and that they are built closer to the urban areas of the state since most riders are coming from these areas.

Pollution from metal mining has led to severe environmental damage. The assessment of metals is very complex as they interact with a broad spectrum of biotic and abiotic components depending on physicochemical conditions. Worldwide, discharges from ancient mines are considered one of the major causes of point and diffuse pollution. This thesis investigated the sources and mobility of metal pollution associated with historical mining in a carboniferous upland catchment, located in the Northern Pennines in the UK. From chemical analysis and geochemical modelling I identified metal sulphates and metal carbonates as the main mineral sources of metals. I also demonstrated that metal carbonates are controlling metal mobility, while seasonality is also producing changes in flow and pH conditions, affecting metal concentrations and behaviour. By using speciation modelling, ecotoxicological assessment tools and in situ macroinvertebrate survey I highlighted the dynamics of metals occurring in neutral mine drainage; and suggested the application of environmental quality standards based on bioavailability data within a realistic context relating response of aquatic organisms to river water chemistry and metals. I also evaluated the effects of episodic rainfall on aqueous metal mobility and toxicity to address some knowledge gaps. I found that rainfall conditions did not alter the circumneutral conditions of the catchment, although metal mobility and speciation were affected by the abundance of carbonate and bicarbonate minerals derived from bedrock weathering. I showed that metal toxicity occurred at circumneutral pH, and mainly attributable to zinc. Moreover, I assessed the effects of episodic rainfall in metal toxicity and calculations revealed that short-term fluctuations of metal concentrations are not reflected in the predicted acute toxicity risk to aquatic organisms, underlining the complexity of chemical speciation especially during episodic events. Likewise, I provided a baseline for future mitigation strategies for catchments under risk of metal pollution. Finally, I stressed the importance of the public perception and community involvement in a holistic management of catchments for protecting riverine ecosystems and improving their water quality. Overall, this thesis provides the evidence that a comprehensive metal assessment requires a great understanding of processes and reactions occurring from metal sources to potential endpoint environments (e.g. water, sediments, and biota). For regulatory purposes, technical knowledge needs to be sensibly transferred to the community for achieving an effective integrated catchment management. Findings from this thesis are suitable for the assessment of streams draining spoil waste areas with similar geochemical conditions and inform future management strategies.

Physical disturbance in the form of storm events has been implicated as a major determinant of community structure in streams. But there has been limited study of this effect on individual taxa within the communities. Such work is needed because of untested assumptions regarding the behavior of bioindicator species in these systems. Development of intricate indices of insect tolerances to organic pollution have become commonplace in environmental monitoring. However, research on the effects of natural disturbance on biological water quality assessment is lacking. Hydropsychid caddisflies are relatively intolerant to organic pollution and the United States Environmental Protection Agency has outlined the use of these organisms and others as an indication of clean water. If a species is recorded as absent from samples when it is present but hidden, this false negative would bias the water quality assessment. I tested hypotheses regarding the behavior of hydropsychid caddisflies facing increased discharge, and the effect of stream size on the magnitude of this phenomenon.Three sites along the West Fork of the White River, Indiana USA were studied during nine storms between 2001 and 2004. Stratified sampling from the upper 15 cm of substrate prior to and just after a storm, and again following reestablishment of normal flow, revealed alterations of hydropsychid distributions. During storms all but one species sought refuge in the hyporheic zone at depths dependent upon storm intensity. The possibility that poor water quality resulting from increased discharge caused the hydropsychid behavior was refuted by chemical analysis. Family level biotic index (FBI) data demonstrated that increased discharge results in a reduction of stream FBI values. These results indicate that high intensity storm events influence biological monitoring and should be factored into sampling protocol.
Department of Biology

The goal of this thesis was to examine the sources and ecological behaviour of genotoxic organics in the St. Lawrence river system. A rapid and effective version of the SOS Chromotest was developed to accomplish the task of genotoxicity assessment. The method, validated with standard reference materials, is particularly well suited to complex environmental extracts. The endpoint investigated throughout the thesis, SOS genotoxicity, is empirically related to more familiar endpoints such as mutagenicity and carcinogenicity. Analyses of literature data confirmed correlations between SOS genotoxicity and both Ames/Salmonella mutagenicity and animal carcinogenicity. Analyses of industrial and municipal wastewaters revealed that organic and inorganic chemical production facilities, metal refining and founding facilities and petroleum refineries release high potency wastes. Loading values indicate that low potency sources (e.g. municipal wastewater and pulp & paper facilities) often have exceptionally high loadings. A substantial portion (2.3-99.8%) of industrial genotoxins are associated with suspended particulates. Sorption partition efficients (K$ sb{ rm d-genotox}$) indicate that municipal wastewater and pulp & paper facilities release particularly soluble genotoxins. Extracts of suspended particulate matter collected near industrial discharges are direct-acting. Bottom sediment extracts are less potent and usually require S9 metabolic activation. Genotoxicity of both bottom sediment and suspended particulates are empirically related to the genotoxicity of regional industrial emissions. Direct-acting substances in the water column appear to be less stable and may be converted to more stable pro-genotoxic substances present in the bottom sediments. A mass balance of genotoxicity for St. Lawrence surface waters revealed that domestic, rather than industrial sources make the largest contribution to observed genotoxicity. The importance of domestic wastes was confirmed

Thesis (MScIng)--Stellenbosch University, 2007.
Some digitised pages may appear illegible due to the condition of the original hard copy.
ENGLISH ABSTRACT: The uranium leaching behaviour of ore from three different mines in the Vaal River region, namely Kopanang, Great Noligwa and Moab Khotsong, was investigated. The aim of the work was to characterise the uranium leaching behaviour of the different ores. It involved a full mineralogical evaluation of the ore as well as determining optimum operating conditions for maximum extraction of uranium, relating the extractions to mineralogical features of the ores. The major bulk minerals in the three Vaal River ores have been identified and consist primarily of quartz (70-80 %), with lesser amount~ of muscovite (8-11%). Moab Khotsong and Noligwa ore samples were found to be very similar, and Kopanang is different from the two ores. Kopanang ore has less pyrite, quartz, and chlorite than the other two ores, but contains more pyrophyllite. Chlorite is an acid consumer and a Fe2+/Fe3+ producer in uranium leaching. The difference in mineralogy of the three ores definitely reflected in the reagent profiles during acid leaching of uranium, specifically acid consumption. With regards to uranium occurrence, bulk uranium analysis showed that 80-90 % of the uranium in the ores is contained as uraninite, 8-19 % as brannerite, and the balance as traces of coffinite and uranium phosphates. Uranium grain sizes were found to be very small, with 50 % of the particles passing 19.4, 21.3 and 23.2 IJm for Kopanang, Noligwa and Moab Khotsong respectively. The degree of liberation of the uranium-bearing minerals was low, between 11 and 45 %, and expectedly increased as particle size decreased. However, between 87 and 93 % of the uraninite particles and 71 to 86 % of the brannerite particles have more than 10 % of their surfaces exposed, and even higher proportions have more than 5 % of their surfaces exposed. The primary experiments were designed within practically attainable boundaries, although special experiments were performed outside the boundaries during subsequent mechanistic studies. H2S04 addition varied between 10 and 25 kg/t, temperature varied between 40 and 60°C, and Mn02 addition varied between 2 and 4 kg/t (100 percent Mn02). Mn02 was added as pyrolusite, 1.5 hours after addition of acid. A relative pulp density of 1.55 was used. Leaching times of 24 and 48 hours were investigated. The ore was milled to 80 % -75 IJm, even though coarser grinding was also investigated. It was found that 60-90 % dissolution could be achieved as leaching conditions were varied within the operating window. Acid addition had the greatest influence on final uranium extractions. Practically useful results, within the operating window attainable in a plant, can be summarised as follows: • Uranium dissolutions are 80-85 % for Great Noligwa and Moab Khotsong ores, and 85-90 % for Kopanang ore • Required residence time = 24 hrs • To achieve the above dissolutions, Kopanang ore requires at least 11 kg/t acid, while acid requirements for Great Noligwa and Moab Khotsong ores are 14 and 16 kg/t respectively • MnOz addition can be kept at a minimum, because sufficient Fe can be leached from the ore (meaning only enough MnOz for conversion of ferrous to ferric needs to be added) • The chlorite dissolution reaction consumes acid, generates ferric and ferrous ions, but also generates dissolved silica. Therefore, the kinetics of this reaction must be understood in order to control it to the lowest extent possible, without impairing the availability of dissolved iron. An understanding of the factors responsible for the leaching behaviour of uranium-bearing ores is critical in achieving optimal uranium recoveries. This is particularly important in light of the fact that dissolutions higher than 90 % are very difficult to achieve under the normal operating conditions employed on the South African acid leaching plants. While solubility limitations were initially suspected, it was found that the reason for the existence of the upper limit for dissolution was most likely due to the presence of aerially locked uranium minerals (uranium minerals that is not exposed to the leaching environment). However, residue analysis showed that most of the uraninite dissolved and that the major fraction of unleached uranium existed as brannerite which is in fact exposed to the leaching environment. Therefore, the slow leaching kinetics / intrinsic inertness of brannerite was considered as the limiting factor for not achieving optimum recoveries. To achieve optimal extraction, considering the mineralogical characteristics of the ores (in terms of a plant's flow/operational perspective), a diagnostic leaching approach was followed. A mineralogyleachability explanation is presented to rationalise the difficulty in exceeding 90 % dissolution from low grade uranium ores on the basis of a novel diagnostic leaching method. More specifically, to determine the interrelationship between mineralogy, mineral liberation and the leaching behaviour of uranium, a methodology was developed for unlocking uranium by a combination of chemical (drastic leaching of minerals associated with the residual uranium) and physical (fine grinding to increase area exposure and liberation) methods. Diagnostic leaching results indicated that to improve uranium dissolution beyond 90 %, uneconomical conditions (residence time between 48 and 72 hours, constant pH = 1 or Eh = 700 mV) need to be considered and it will still not necessarily be possible to increase beyond 95%. The maximum obtained is 98% using nitric acid digestion at evaluated temperatures (900C). Mineralogical analysis indication that it is possible to leaching brannerite but, the leaching kinetics thereof is very slow. Based on the diagnostic leaching tests the following is recommended for the tree ores tested: Sulphuric acid leaching must be used for treating Kopanang ore. If the brannerite concentration of Noligwa and Moab Khotsong ore is < 20 % sulphuric acid leaching is recommended but if the brannerite concentration> 20 % other leaching methods will be recommended (Le. pressure leaching or using a different leaching reagent). A non-linear decision tree model was developed for modelling of the experimental data and is presented in this thesis. In this context it would be more realistic to determine a range for expected recovery rather than trying to determine an exact value. Therefore, a classification tree model was used. Using this method, just evaluating the tree shows that: For uranium dissolution higher than 70% a residence time longer that 17 hours is required including an acid addition higher that 11.35 kg/t for Noligwa and Moab Khotsong ore while lower acid concentration can be tolerated for Kopanang ore. It is proven that that model can with 86% accuracy separate that into the various classes. Through cross validation it is also proven to be a representative model with an average success rate of 84 % for classification of data with a standard deviation of 2.8%. This model can be used to predict the expected dissolution range based only on the operating parameters within the Vaal River context. Since the model is based on laboratory experimental data it can not necessarily be used for plant operation/optimisation purposes. It is recommended to develop an equivalent model using pilot plant data to develop a more accurate model which can also be used for optimisation purposes. Although it is not part of the original scope of the project (based on the information gained though out the project), a proposal of an empirical model simulator is also presented. Since development of the simulator is still in the developing stages, this thesis will only include the algorithm as well as a basic model predictor which can be used for future research. The ideal is to develop a simulator has the ability to predict uranium leaching behaviour and reagent consumption based on mineralogy. Gold extractions obtained by forward leaching (direct cyanide leaching of gold) were compared with those obtained by reverse leaching (sulphuric acid leaching of uranium followed by cyanide leaching of gold) for three different Vaal River ores, to quantify the benefits of reverse leaching option. Reverse leaching of gold recovery by between 3 and 4 percentage points, improving total gold recovery to 98 %. A gold benefit of between 0.4 and 0.6 g/t was measured. The exact financial gain is dependant on the gold price and other economic factors, but an estimated benefit for treating an average of 240000 t ore/month is in the order of R 14000 OOO/month. The reverse leaching operation for the recovery of both gold and uranium is therefore a financially justified process route, because recovery of uranium will ensure that the costs are lower than the revenue increment.
AFRIKAANSE OPSOMMING: Die logingsgedrag van uraan erts vanaf drie verskillende myne in the Vaalrivier omgewing, naamlik Kopanang, Noligwa en Moab Khotsong is ondersoek. Die doel van die studie is die karakteriseering van die uraan logingsgedrag en behels 'n indiepte mineralogiese evalueering van die verskillende ertse, die bepaling van die optimale bedryfskondisies vir die ekstraksie van uraan as ook die bepaling van 'n verband tussen ekstraksie en mineralogiese eienskappe van die erts. Die grootmaat minerale van die drie Vaalrivier ertse is geidentifiseer en bestaan hoofsaaklik uit kwarts (70 - 80 %), met 'n laer konsentrasie muskoviet (8 - 11 %). Daar is gevind dat die Moab Khotsong en Noligwa erts monsters tot 'n groot mate ooreenstem, terwyl Kopanang erts daarvan verskil. Kopanang erts bevat minder piriet, kwarts en chloriet maar meer pirofilliet in vergelyking met die ander twee ertse. Chloriet is 'n suur verbruiker en 'n Fe2+/Fe3 + verskaffer in uraan logings prosesse. Dit blyk uit die resulte dat die verskil in die mineralogie van die drie ertse definitief reflekteer op die reagense profiele tydens suur loging van uraan, veral suur verbruik. Die grootmaatanalise, in terme van die aanwesigheid van uraan, toon dat 80 - 90 % van die uraan in die erts voorkom as uraniniet, 8 - 19 % as branneriet en die balans kom voor as koffiniet en uraanfosfate. Daar is gevind dat die uraan korrelgrootte baie klein is, met 50 % van die partikels kleiner as 19.4, 21.3 en 23.2 IJm vir Kopanang, Noligwa en Moab Khotsong respektiewelik. Die graad van bevryding van die uraan bevattende minerale was laag (tussen 11 en 45 %) en neem na verwagting toe soos partikel grootte afneem. Nietemin, tussen 87 en 93 % van die uraniniet partikels en 71 _ 86 % van die branneriet partikels het meer as 10 % van die mineraal oppervlakte blootgestel aan die logings omgewing met selfs hoer proporsies met meer as 5 % blootgestelde oppervlak area. Die primere eksperimente was ontwerp binne die praktiese grense haalbaar op 'n aanleg. Spesiale eksperimente was wei ook uitgevoer buite die grense, vir opeenvolgende meganistiese studies. H 2 S0 4 byvoeging was gevarieer tussen 10 en 25 kg/t, temperatuur gevarieer tussen 40 en 60°C en Mn02 byvoeging is gevarieer tussen 2 en 4 kg/t (100 persent Mn02)' Mn02 is toegevoeg as pirolusiet 1.5 uur na die toevoeging van die suur. 'n Relatiewe pulp digtheid van 1.55 was gebruik. 'n Loging residensie tyd van 24 en 48 uur was ondersoek. Die erts was gemaal tot 80 % -75 IJm alhoewel growwer maling wei ook ondersoek is. Daar is gevind dat 60 - 90 % oplossing wei bereikbaar is binne die bedryfsgense. Dit blyk dat die suur byvoeging die grootste invloed het op die finale uraan ekstraksie. Praktiese nuttige informasie, binne die bedryfsgense van 'n aanleg, kan as volg opgesom word: • Uraan oplossings tussen 80 - 85 % vir Great Noligwa en Moab Khotsong erts en tussen 85 - 90 % vir Kopanang erts. • Vereiste residensietyd = 24 uur • Om begenoemde oplossings te bereik, benodig Kopanang erts ten minste 11 kg/t suur, terwyl die suur vereistes vir Noligwa en Moab Khotsong erts 14 en 16 kg/t is onderskeidelik • Mn02 toevoeging kan tot 'n minimum beperk word aangesien voldoende Fe geloog word vanaf die erts (dus sleg genoeg Mn02 vir die omskakeling van Fe2+ na Fe3+ word benodig) • Die chloriet oplossings reaksie verbruik suur en genereer Fe3 + en Fe2+ as ook silika in oplossing. Dit is dus belangrik om die kinetika van die reaksie te verstaan om sodoende die reaksie tot 'n groot mate te onderdruk sonder om die beskikbare yster in oplossing te beinvloed 'n Deeglike begrip van die faktore verantwoordelik vir die logingskarakteristieke van uraan bevattende ertse is krities om 'n optimale uraan opbrengs te bereik. Dit is veral belangrik aangesien oplossings hoer as 90 % moeilik is om te bereik onder die normale beheer kondisies wat gebruik word op Suid Afrikaanse suurlogingsaanlegte. Terwyl oplosbaarheidsbeperkings oorspronklik verdink was, is daar gevind dat die bestaan van 'n hoer limiet vir uraan oplosbaarheid waarskynlik 'n gevolg is van die teenwoordigheid van area geslote uraan minerale (uraan minerale wat nie aan die logings area blootgestel is nie). Nietemin, residu analiese toon dat die meeste van die uraniniet opgelos het en dat die grootste fraksie van ongeloogde uraan voorkom as brannerite, wat wei bloot gestel is aan die logings omgewing. Gebaseer op die bevindings word die stadige loging kinetika / intrisieke traagheid van brannerite gereken as die beperkende faktor vir optimum uraan herwinnig. Om optimale ekstraksie te bereik, gelet op die mineralogiese karakteristieke van die erts (in terme van 'n aanleg se vloei / beheer perspektief), was 'n diagnostieke logingsbenadering gevolg. 'n Mineralogiese-uitloging verduideliking word bespreek om die beperking van oplossings hoer as 90 % te bespreek vir lae graad uraan ertse wat gebaseer is op 'n stap vir stap diagnostiese metode. Meer spesifiek, om die interaksie tussen die mineralogie, mineraal bevryding en logingsgedrag van uraan te bepaal is 'n metodologie ontwikkel om uraan minerale te bevry deur 'n kombinasie van chemise (drastiese loging van minerale geassosieer met die residu uraan) en fisiese (fyn maling om die area van blootstelling en bevryding van uraan minerale te vergroot) metodes. Die diagnostiese resultate wys daarop dat om uraan oplossing te verhoog bo 90 %, onekonomiese kondisies (residensie tyd tussen 48 en 72 uur, konstante pH =1 of Eh = 700 mV) oorweeg moet word en dit nie noodwendig oplossings hoer as 95 % bewerkstellig nie. Die maksimum ekstrasie wat bereik was is 98 % tydens salpetersuur vertering by hoe temperature (90°C). Mineralogiese analieses wys daarop dat dit wei moontlik is om branneriet te loog maar dat die loging kinetika baie stadig is. Gebaseer op die diagnostieke logings resultate word die volgende aanbeveel: Swawelsuur loging vir die behandeling van Kopanang erts. Indien die konsentrasie van branneriet in Noligwa and Moab Khotsong erts laer is as 20 % sal swawelsuur loging aanbeveel word maar indien dit verhoog (>20 %) moet ander logings tegnieke oorweeg word (bv. drukloging of die gebruik van ander logings reagense) 'n Nie linieere besluit boom model was ontwikkel vir die modelering van die eksperimentele data en word weergegee in die tesis. Aangesien daar meer waarde Ie in die bepaling van 'n verwagte uraan oplossings in 'n bepaalde gebied, eerder as om die presiese waarde te probeer bepaal is dit as 'n klassifikasie model hanteer. Deur hierdie metode te volg kan daar, gebaseer op die ontwikkelde boom die volgende afleidings gemaak word: Om oplossing bo 70% te bereik is 'n residensie tyd van langer as 17 uur benodig as ook 'n suur toevoeging van meer as 11.35 kg/t vir Noligwa en moab Khotsong erts terwyl minder suur benodig word vir Kopanang erts. Daar is getoon dat die model met 86 % akkuraatheid die data kan skei in die verskillende klasse. Kruis valideering van die model toon dat dit verteenwoordigend is en gemiddeld 84 % sukses behaal in die klassifiseering van data met 'n standard afwyking van 2.8 %. Hierdie model kan gebruik word om die verwagte oplossings gebied te voorspel gebaseer op die beheer veranderlikes binne the Vaalriver konteks. Aangesien die model gebaseer is op laboratorium gegenereerde data kan dit nie noodwendig gebruik word vir aanleg beheer doeleindes of optimiseering nie. Daar word dus aanbeveel om dieselfde model te ontwikkel vir proef aanleg data om 'n meer akkurate model te ontwikkel wat gebruik kan word vir optimiseerings doeleindes. Alhoewel dit nie deel was van die oorspronklike omvang van die projek nie (gebaseer op die informasie versamel deur die verloop van die projek) word 'n voorstel van 'n empiriese model simulator bespreek in die tesis. Aangesien die ontwikkeling van die simulator nog in die ontwikkelings fase is sal die tesis slegs die algoritme as ook 'n basiese model voorspeller simulator insluit wat vir toekomstige navorsing gebruik kan word. Die ideaal is om 'n simulator te ontwikkel wat die vermoee het om die uraan logingsgedrag te voorspel as ook die reagense verbruik gebaseer alleenlik op mineralogie. Goud ekstraksies verkrygbaar deur voorwaartse loging (direkte sian ide loging van goud) is vergelyk met ekstraksies verkry deur terugwaartse loging (swawelsuur loging van uraan gevolg deur sianide loging van goud) vir die drie verskillende Vaal rivier ertse. Die hoof doel is die kwantifiseering van die voordele ten opsigte van terugwaartse loging. Terugwaartse loging van gold verhoog die goud opbrengs tussen 3 en 4 persentasie punte wat lei tot 'n totale gold herwinning van 98 %. 'n Goud wins van tussen 0.4 en 0.6 g/t is bepaal. Die presiese finansieele wins is sterk afhanklik van die goud prys en ander ekonomieses faktore, maar 'n geskatte wins vir behandeling van gemiddeld 240000 t erts/maand is in die orde van R 14000 OOO/maand. Daarom is die terugwaartse logingsmetode vir die herwinnig van beide goud en uraan 'n finansieel geregverdigde proses roete.

Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.
Title from electronic title page (viewed Jun. 23, 2010). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Marine Sciences Physical Oceanography." Discipline: Marine Sciences; Department/School: Marine Sciences.

The objective of this study was to understand the pattern of variation in group structure and feeding behaviour of wintering Common Goldeneyes ( Bucephala clangula) on the Saint-Lawrence River, by comparing two major habitats for this species in the province of Quebec, one in freshwater and one in saltwater. Groups of goldeneyes were smaller in Montreal than in the estuary and consisted of twice as many males. Individuals spent a greater proportion of time feeding in Montreal than in the estuary. At Montreal, goldeneyes spent more time feeding under water. Temporal variables had a major influence on group structure and on diving time. At Montreal, time of day explained most of variation whereas in the estuary, tide was more important.

The Common River Frog Amietia quecketti is a well-known and widely distributed species in southern Africa. Despite the fact that it is a common species and quite prevalent in urban areas little is known about its behaviour. The North-West University Botanical Gardens was selected as study area as it supports a healthy population of Common River Frogs at a series of 18 water bodies. Each pond in the Garden was assigned a reference number and the surface area, depth and vegetation were noted. Frogs were located with the aid of strong flashlights. Specimens were caught by hand and transferred to clear plastic bags. Frogs were sexed and their mass and their snout-vent length (SVL) were determined. Frogs were subsequently individually marked by means of injecting a micro-transponder (pit-tag) subcutaneously. Field observations were conducted over two consecutive evenings every two weeks for a period of one year. On the first night all sites were visited and all frogs were scanned and their position, orientation and activity were noted. During the second night focus was on Pond 6 as it sustained the biggest population. Observation started at 19:15 and continued until 02:30. All frogs in and around the pond were scanned and detailed notes were taken, focusing on their orientation, behaviour, calling activity and distance to the nearest other frog. Results showed that limited movement between ponds in the Garden does occur. A number of individuals were recorded regularly. Some males had preferred call sites, and clear circadian and seasonal patterns with regards to males and females exist. The complex call structure consist of a chuck and a whine and then a combination of the two.
MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2013

This is a study of axial and transverse slip in helically wound armour wires on flexible pipe under the influence of end restraint. Analysis of steel strip layers in order to find the effect of end restraint prompted the development of a new model to describe their behaviour. This avoids the shortfalls of adapting previous models designed either for similar but different structures or for application away from any end fitting restraint. Previous analytical solutions concerning flexible pipe tensile armour have concentrated on pre-defined paths on the supporting surfaces, these being strained helices or geodesic curves, and have avoided any consideration of end effects. The work presented here is aimed at finding the path adopted by armour wires approaching end fittings, and the resultant stresses and slip. A model is developed which uses small changes in helical angle along the strip to describe tensile armour configuration as a flexible pipe is bent and stretched. The problem is characterized by a strip on a cylinder at a variable angle to its axis which itself has a variable curvature applied to it. A solution is found by minimizing total strain energy to find stress concentrations and slip characteristics. The simplest case of a straight pipe under tension is solved first, followed by a more typical flexible riser configuration involving bending under tension. The results show that under frictionless conditions tensile armour wire slips to reduce tension and that near the end fitting this slip leads to increased bending stresses in some or all of the wires. The model is applied to typical riser designs for the transport of oil and gas to find the location and level of the greatest increases in stress. Their sensitivity to pipe design parameters is also assessed.

Pre-vegetation alluvium is unique; at the present day, plants affect multiple aspects of river functioning and deposition and so those rivers that operated before the evolution of land plants largely lack modern sedimentological analogue. However, such rivers were the norm for the first 90% of Earth history and so a better understanding of their sedimentary product enables insight into both the fundamental underlying mechanisms of river behaviour and the ways in which fluvial processes operated on ancient Earth and other rocky planets. This study presents five original fieldwork based case studies and an analysis of a holistic database of all of Earth’s pre-vegetation alluvium. Together these research strands offer perspectives on the sedimentological characteristics and stratigraphic trends of pre-vegetation alluvium and the behaviour and functioning of pre-vegetation rivers. Results show that, in pre-vegetation alluvial settings: 1) a variety of fluvial styles are represented, but diminished in comparison with syn-vegetation alluvium; 2) ‘sheet-braided’ architectures are common but may record a variety of fluvial planforms; 3) meandering planforms were less frequent, particularly in small- to moderate-sized river systems; 4) mudrock is on average 1.4 orders of magnitude less common than it is in syn-vegetation alluvium; and 5) microbial matgrounds were present, but had negligible effect on preserved architecture and facies. This thesis demonstrates that whilst the physical laws governing fluvial fluid-sediment interaction have not changed, the theatre in which they operated irrevocably evolved with the greening of the continents.

[EN] The understanding of the mechanical behaviour of natural intact soils is central to engineers when designing new structures. The research carried in this thesis focused on investigating the effects of the naturally occurring in-situ structure on the mechanical behaviour of two shallow recently deposited Holocene alluvial materials, the Bormida River silts (BRS) from Italy and the Valencia silty soils (VSS) from the alluvial plains of the Turia River, Spain. These types of deposits are frequently characterised by highly heterogeneous in-situ structures. A large range of soils with different size distributions from sands to silty clays were investigated. Oedometer and triaxial tests were carried out on intact, slurry and compacted samples. The first step was to characterise the behaviour of the materials at their reconstituted state to define the reference framework for investigating the effect of the in-situ structure of the intact specimens. The effects of the sample preparation technique on the mechanical behaviour were examined, in particular its influence on the uniqueness of the normal compression line and critical state line. The initial structure created during the preparation of the specimens was totally removed after compression and shearing regardless of the sample preparation method. Only one soil displayed a clear effect of the sample preparation technique, the oedometer compression lines of which remained parallel to each other even at a very high stress levels for the case of the slurry samples. This result showed that contrary to what is stated in the literature the sample preparation technique can created very robust initial structures resulting in a transitional behaviour. Clears effects of the in-situ structure of the intact samples of the BRS and VSS were observed on the oedometer compression behaviour even at very high stress levels with stress sensitivity values still larger than unity at the end of the tests. It appeared that the effects were more noticeable as the degree of heterogeneity inside the specimens increased at a meso-structure level as it was the case of some samples of the VSS materials which exhibited a certain layering. Small effects of the in-situ structure were seen at large shearing strains and only on the wet side of the critical state.
[ES] El conocimiento del comportamiento mecánico de los suelos en su estado natural es de importancia capital para los ingenieros a la hora de diseñar nuevas obras. La investigación desarrollada en esta Tesis se centra en descubrir los efectos que tiene la estructura del suelo en su estado natural en la respuesta mecánica de dos suelos aluviales holocenos, depositados superficialmente: los limos del río Bormida (BRS) en Italia y los suelos limosos provenientes de la llanura aluvial del río Turia (VSS) en España. Este tipo de suelos se caracterizan frecuentemente por una estructura inicial altamente heterogénea. Se ha ensayado una gran variedad de muestras con diferentes granulometrías, desde arenas a arcillas limosas en las que se han realizado ensayos edométricos y triaxiales en muestras intactas, compactadas y en muestras reconstituidas (slurry). En una primera etapa de la investigación se caracterizó la respuesta del material en su estado reconstituido para definir un marco de referencia con el que poder comparar la respuesta de las muestras intactas tomadas in situ y que preservan su estructura natural (inalteradas). Se ha analizado la influencia del modo de preparación de las muestras en su comportamiento mecánico, y, en particular, en la unicidad de las curvas de compresión noval y de estado critico. Se ha comprobado que la estructura inicial inducida durante el proceso de preparación desaparece completamente tras someter la muestra a compresión y corte, independientemente del método de preparación utilizado. Únicamente un suelo mostró, de un modo nítido, el efecto de la técnica de preparación, de modo que las líneas de compresión edométrica se mantuvieron paralelas incluso a niveles de tensión elevados en el caso de muestras reconstituidas (slurry). Este resultado demostró, contrariamente a la opinión aceptada en la bibliografía, que el sistema de preparación de la muestra puede crear una potente estructura inicial dando lugar a un comportamiento de tipo transicional. En los ensayos de compresión edométrica se ha podido comprobar un claro efecto positivo de la estructura inicial de las muestras intactas, incluso a niveles altos de tensión, observándose índices de sensitividad tensional superiores a uno al final de los ensayos, de modo que para igualdad de índice de huecos, la tensión efectiva vertical de la muestra intacta es superior a la correspondiente en la muestra reconstituida. Aparentemente, este efecto es tanto más significativo cuanto mayor es el grado de heterogeneidad interno de la muestra a nivel de meso-estructura, como se pudo observar en algunas muestras de los suelos (VSS) que presentaban niveles de laminación horizontal. En los ensayos de corte la influencia de la estructura intacta fue relativamente pequeña y únicamente en el lado húmedo del estado critico.
[CAT] Conèixer el comportament mecànic dels sòls en el seu estat natural és d'importància capital per als enginyers a l'hora de dissenyar noves obres. La investigació desenvolupada en aquesta Tesi se centra a descobrir els efectes de l'estructura del sòl en el seu estat natural en la resposta mecànica de dos sòls al¿luvials holocens, dipositats superficialment: els llims del riu Bormida (BRS) a Itàlia i els sòls llimosos provinents de la plana al¿luvial del riu Túria (VSS) a Espanya. Aquests tipus de sòls es caracteritzen sovint per una estructura inicial altament heterogènia. S'ha assajat una gran varietat de mostres amb diferents granulometries, des d'arenes fins a argiles llimoses amb les quals s'han realitzat assajos edomètrics i triaxials en mostres intactes, compactades i en mostres reconstituïdes (slurry). En una primera etapa de la investigació es va caracteritzar la resposta del material en el seu estat reconstituït per a definir un marc de referència amb el qual poder comparar la resposta de les mostres intactes preses in situ i que preserven la seua estructura natural (inalterades). S'ha analitzat la influència del mètode de preparació de les mostres en el seu comportament mecànic i en particular, en la unicitat de les corbes de compressió noval i d'estat crític. S'ha comprovat que l'estructura inicial induïda al llarg del procés de preparació desapareix completament després de sotmetre la mostra a compressió i tall, independentment del mètode de preparació utilitzat. Únicament un sòl va mostrar clarament l'efecte de la tècnica de preparació, de manera que les línies de compressió edomètrica es van mantenir paral¿leles fins i tot a nivells de tensió elevats en el cas de mostres reconstituïdes (slurry). Aquest resultat va demostrar, contràriament a l'opinió acceptada en la bibliografia, que el sistema de preparació de la mostra pot crear una potent estructura inicial donant lloc a un comportament de tipus transicional. Als assajos de compressió edomètrica s'ha pogut comprovar un clar efecte positiu de l'estructura inicial de les mostres intactes, inclús a nivells alts de tensió, observant-se índexs de sensitivitat tensional superiors a la unitat al final dels assajos, de manera que per a igualtat d'índex de buits, la tensió efectiva vertical de la mostra intacta és superior a la corresponent en la mostra reconstituïda. Aparentment, aquest efecte és més significatiu quant major és el grau d'heterogeneïtat intern de la mostra a nivell de meso-estructura, com es va poder observar en algunes mostres dels sòls (VSS) que presentaven nivells de laminació horitzontal. Als assajos de tall la influència de l'estructura intacta va ser relativament petita i únicament en el costat humit de l'estat crític."
Carrión Carmona, MÁ. (2016). The effects of the structure on the mechanical behaviour of young Holocene alluvial materials from the Bormida River (Italy) and Turia River (Spain) [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63470
TESIS

Quantifying spatial and temporal patterns of rapid channelized erosion, on human time scales, is critical to understanding its processes and their consequences. This investigation utilized field observations, repeat terrestrial laser scanning (TLS), and Structure-from-Motion photogrammetry (SfM) to document the size and retreat rates of a knickpoint, defined as a localized near-vertical reach of a fluvial channel, and its contribution to erosion, in an urbanizing landscape with a loess substrate. The Bull Mountain area, in Washington County, southwest of Portland, Oregon, is an ideal study area, offering a measurable knickpoint that translates the response of the rapid erosion throughout this transient system. Previous urbanization there has increased peak flows in streams, potentially initiating rapid channel incision and associated slope instability and sediment pollution, affecting real property and infrastructure. Despite the documented increase in discharge, upstream migration rates of the knickpoint, as well as the overall channel erosion rate, were unknown. Sequential point cloud analysis quantified topographic changes in the landscape, in three dimensions, throughout time. The measured minimum knickpoint migration rates ranged from - 0.23 m/yr to - 2.45 m/yr with an average of - 1.52 m/yr and minimum of total volume eroded of 6.49 m3. The negative sign indicates the upstream direction. An extreme erosion event caused - 12.5 m of erosion in ~ 4.5 months. The interval including the extreme erosion event was recorded separately using traditional measurement techniques and resulted in an average retreat rate of - 4.31 m/yr. Analysis of patterns of erosion revealed four primary modes: exfoliation, large soil block failure, undercutting at the knickpoint base, and upper bank failure. Results from soil analyses indicate a layer of high bulk density (1.85 g/cm3) loess at the base of the upper channel may restrict the channelized incision for that reach and control the height and geometry of the knickpoint face, leading to a parallel mode of retreat. From the observed erosion rates a substrate specific average value of erodibility, or K value, of 0.01 m0.2 yr-1, was determined. As erosion forces the retreat of these knickpoints upstream, the effects of increasing urban runoff are felt throughout the watershed. The work presented here provides insight on the physical controls driving erosion and can serve as a prologue for future mitigation.

Shrimp farming is important to the Vietnamese economy in terms of national income, job creation and poverty alleviation. However, shrimp farming is generally technically inefficient and probably generates too much pollution. To encourage the sustainable development of the Vietnamese shrimp industry, there is a need to improve the productivity of shrimp farms and at the same time to reduce the wastewater pollution generated by shrimp farming. The thesis has two aims: (1) to estimate the efficiency of shrimp farms in the Mekong Delta of Vietnam, with a particular focus on the productivity effects of pollution, and (2) to use experimental economics to investigate policies that could be used to mitigate the wastewater pollution impacting shrimp farms. Overall farmers are found to be inefficient, suggesting farmers are using more inputs than necessary to produce a given output level. Surprisingly, the average extensive (i.e., less capital-intensive) farm is found to be more efficient than the average intensive and semi- intensive (i.e., more capital-intensive) farms. Furthermore, downstream farms are found to be less efficient than upstream farms, suggesting that wastewater pollution influences shrimp farming productivity and results in a negative externality. Evidence from lab-based experiments suggests that the incentives provided by a monitoring and certification agency are not sufficient to promote the full cooperation of shrimp farmers to solve the wastewater pollution problem. However, full cooperation was achieved by providing farmers with an opportunity to communicate. In both cases, self-governance of shrimp farmers was found to be highly effective. The results suggest that community-based management is worthy of further investigation as a possible solution to sustainable development of the shrimp industry in Vietnam. "What we have ignored is what citizens can do and the importance of real involvement of the people involved – versus just having somebody in Washington ... make a rule." Elinor Ostrom (1933-2012)

This study investigated various life history stages of salmonids within the River Tweed, UK with a focus on migratory movements. The River Tweed is a large upland river situated on the border between Scotland and England and is home to some of the healthiest stocks of Atlantic salmon (Salmo salar) and sea trout (Salmo trutta) in the UK. The research undertaken as part of this thesis aims to assess how management can be improved to aid the migration of salmonids moving within freshwater. This is of particular importance due to increased demand for renewable energy including small scale hydropower as well as legislation that demands improved fish passage within rivers such as the Water Framework Directive. Sea trout smolts were captured and acoustic tagged to assess the roles that in river obstructions such as weirs play on their migration between years with varying river flow. The two study years varied radically in flow levels due to the incidences of hydrological drought in 2010 significant differences were observed in the degree of delay smolts experienced at weirs as well as differing responses to flow during years. Sea trout and salmon were acoustic tagged and tracked during their freshwater spawning migration. The aim of the study was to examine the interspecific differences in spawning migration such as spawning location and movement rate during migration. By looking at migration rate of sea trout and salmon it was observed that both species decreased their migratory rate the further into the river system they moved. It was also observed that sea trout and salmon spawned in different locations, with sea trout using tributaries and salmon using lower stretches of the Tweed. The small scale movements of freshwater resident trout was studied. Freshwater resident trout tend to have relatively small home ranges and often hold a territory within their home range. As a result they also tend to rapidly home back to their territory after being displaced from it. As such, the study aimed to assess the degree to which brown trout home after being displaced, particularly whether being offered a choice of empty territories at their site of displacement would affect their homing behaviour. The study found that there was no apparent difference in homing behaviour observed between treatment groups offered empty territories at their site of displacement compared to controls that were displaced into fully populated sites. Continued research into the behaviour of salmonid species is important due to increasing demand on water resources, future conflict between man and fishes water needs is inevitable.

Two of the three turtle species inhabiting the Murray River, Emydura macquarii and Chelodina longicollis, have declined since the 1970s, whilst C. expansa is rare. As much of the ecology of these turtles and their threats are poorly understood, a comprehensive conservation plan is yet to be drafted. Here, I describe a threat to turtles, investigate aspects of their ecology and behaviour, and evaluate methods for public engagement in turtle conservation. These areas are critical for the design of an effective management plan. In Chapter 2, I describe mortality on roads using data collected via citizen science, and show that C. longicollis is most at risk on multiple-lane highways during their nesting season and after rain. I propose testing road signs, eco-passages and artificial nesting grounds to address this issue. In Chapter 3, I evaluate the consequences of the decline of all three species by quantifying their scavenging role, and show that they are key scavengers that positively affect water quality. Hence, areas with few or no turtles are likely to be most affected by unchecked carrion decay, highlighting the need to address the turtle decline. Headstarting hatchlings may be an effective conservation technique. In Chapter 4, I test whether hatchling E. macquarii associate with aquatic vegetation, and whether captivity affects their behaviour and short-term survival, to inform a headstarting plan. I conclude that E. macquarii hatchlings should be released at hatching in areas with abundant aquatic vegetation. In Chapter 5, I show that skills and knowledge gains after participating in the citizen science project TurtleSAT are associated with behavioural and attitudinal changes that may be beneficial for turtle conservation. This thesis justifies the conservation of the turtles of the Murray River, informs a future conservation plan, and provides an example approach for other poorly known species that are likely to play key roles in their ecosystem functioning.

Strategies animals use to find and consume food in the face of conflicting forces such as competition and predation are central questions in the fields of ecological theory and management. Whereas theoretical models abound, proper empirical tests of these theories are less abundant. In studying the relationship between food abundance, predation risk, and competition there exists an array of confounding factors, which need to be accounted for by manipulating some aspect of the system. I used a guild of spring migratory ducks as a model system and manipulated food abundance in areas differing in presumed risk to assess the relative effects of food abundance, predation risk, competition, and life history characteristics on foraging strategies used by ducks. Using a randomized block design, I established a pair of 0.4 ha plots (block) in emergent, open water, and forested wetlands in the Wabash River Floodplain in eastern Illinois. I randomly selected one plot within each block to supplement with 2000 kg/ha of corn (Zea mays), creating an area of very high duck food abundance next to a control area with no added food. I conducted instantaneous focal animal samples and used video recorders to estimate the proportion of time mallard (Anas platyrhynchos), blue-winged teal (Anas discors), wood duck (Aix sponsa), ring-necked duck (Aythya collaris), and lesser scaup (Aythya affinis) devoted to feeding, identify the specific behaviors used, and estimate feeding stint lengths and frequencies. I used these metrics as an index of risk that ducks were willing to engage in for a known food reward. I predicted that species with a faster life history strategy, factors that increase perceived predation risk (cover, water depth, group size), and increase energetic demand (due to nesting or temperature), would elicit more risk-taking behaviors in ducks. This would be realized by an increase in the proportion of time spent feeding, longer feeding durations, and deeper feeding behaviors in treatment plots compared with control plots. Consistent with my life history prediction, species with a faster life history strategy were willing to engage in more risky behavior (feeding more) for a greater food reward (food treatment). Mallards, lesser scaup, and wood ducks exhibited risk-taking behavior consistent with perceived predation risk. Mallards devoted more time to feeding and used longer feeding stints when in areas with less cover. Alternatively, lesser scaup devoted more time to feeding when in areas of more cover. Wood ducks devoted more time to feeding in treatment plots, when in shallow areas, and larger flocks. When blue-winged teal fed on the surface (eyes above water), they devoted more overall time to feeding indicating that surface feeding is less risky than deeper feeding. Wood ducks and lesser scaup exhibited behavior consistent with an increase in energetic demand as observed by an increase in the proportion of time devoted to feeding later in the spring. I also examined how food abundance influenced aspects of ducks' foraging niches. I found that dabbling ducks used a greater variety of behaviors (behavior niche breadth) when in treatment plots compared to control plots and also shifted to slightly deeper feeding behaviors in treatment plots. This greater breadth when food was more abundant was due to individuals of the same species diverging from one another, rather than each individual using a broader array of behaviors. Overall, I found substantial variability among and within species in how they manage risk while foraging, although this was partially explained by life history theory, and what types of conditions they perceive as risky. I document the importance of taking the state of the forager (life history, perceived risk, energetic demand) into account when examining patterns of risk-taking.

The corrosion fatigue behaviour of high strength carbon steel tensile armour wires that are used in flexible risers has been explored. An investigation of the corrosion fatigue failure mechanisms for two different sets of corrosion fatigue tested high strength steel wires has been carried out. The two different tensile armour wires were 12 mm x 4 mm and 12 mm x 7 mm. The wires had been corrosion fatigue tested in up to three different seawater environments, namely aerated, CO2 saturated to 1 bar absolute and 100 mbar absolute H2S-CO2 balance to 1 bar absolute. The corrosion fatigue failure investigation included undertaking statistical analysis of fatigue crack and corrosion pit data to establish the effects of environment, applied stress, R-ratio and microstructure due to degree of cold drawing on the corrosion fatigue behaviour. The 12 mm x 4 mm has fine grain martensite-pearlite structure with anisotropic microstructure in the transverse plane. The 12 mm x 7 mm has larger grain martensite-pearlite structure with equiaxed microstructure in the transverse plane. The corrosion fatigue crack path for the two tensile armour wires exhibits transgranular and intergranular cracking due to variations in R-ratio and microstructure. The analysis identified that a significant amount of localised corrosion pitting was present on the surface of both the 12 mm x 4 mm and 12 mm x 7 mm high strength carbon steel tensile armour wires and that many corrosion fatigue cracks had initiated from these geometric discontinuities. A method was developed in order to apply an optical image correlation technique to a sample immersed in seawater. The research has shown that digital image correlation may be applied for in-situ imaging of a corroding and dynamically deforming surface within a seawater environment. The technique demonstrated the establishment of localised surface strain around the corrosion pits during mechanical loading. The results of the surface strain mapping show that the interaction between multiple corrosion pits is consistent with a significant increase in surface strain when compared to a single surface pit acting alone. The results also show that a small single stress raiser can exhibit a high surface stress concentration when compared to a larger one as the strain is dependent upon the geometry of the pit. The highest strain concentration is at the edge of the pit, parallel to the loading direction. The results show the interaction that multiple pits have with each other, the effect they have on surface strains and how they and other types of stress raiser lead to premature failure of components. Further to this the effects of residual stress on crack nucleation were considered. Fatigue cracks initiate at the surface of the high strength carbon steel tensile armour wire therefore surface measurements were carried out to establish the effects of environment and applied load on the development of residual stress fields. The 12 mm x 4 mm wire shows some correlation between applied stress range and surface residual stress measurements with. For the 12 mm x 4 mm wire corrosion fatigue tested in aerated seawater the surface residual stress becomes increasing compressive with an increase in applied stress. For the 12 mm x 4 mm wire corrosion fatigue tested in CO2 saturated seawater the surface residual stress appears to be independent of applied stress. However for the 12 mm x 7 mm carbon steel tensile armour wire there is no correlation between the applied stress range and the surface residual stress. The differences in surface residual stress may be due to the differences in R-ratio, microstructure and level of cold drawing due to the Bauschinger effect. Surface residual stress measurements have been used to explore the effects of the shakedown process on the high strength carbon steel tensile armour wires prior to corrosion fatigue testing. They show that at a high applied stress range the shakedown process readily develops a compressive residual stress on the surface of the carbon steel wire. This is mostly the case for the low applied stress range; however care should be taken when considering the effects of shakedown on a lower stress range in so far as it may not completely remove the tensile residual stress. Through thickness residual stress measurements show a similar distribution of residual stress fields throughout the high strength carbon steel tensile armour wires independent of the applied stress range and environment.

A general decrease in populations of waders on the Ythan estuary, Aberdeenshire, has coincided with an increased biomass of green algae on the intertidal mudflats. It was hypothesised that the reduction of bird numbers was due to the impact of macroalgal mats. The main objective of this study was to test the above hypothesis by investigating the impact of macroalgal mats on aspects of the behavioural ecology of waders, principally on their dispersion, diet and foraging behaviour. Redshank (Tringa totanus L.), curlew (Numenius arquata L.), oystercatcher (Haematopus ostralegus L.), bar-tailed godwit (Limosa lapponica L.) and dunlin (Calidris alpina L.; for study of dispersion only) were chosen for study. To test this hypothesis, wader counts on different estuary sections, pellet and dropping analysis, direct observations on foraging, visual and photographic estimations of weed cover, and invertebrate data were assessed in the context of the energetics of waders and their prey described in the literature. Foraging behaviour was examined on weed-covered and weed-free sediments in natural sites and in field-manipulated plots. Weed cover below 25% (biomass <1 kg fresh weight/ m²) did not adversely influence the foraging of redshank, curlew, oystercatcher and bar-tailed godwit. However, weed cover >50% (biomass > 3 kg fresh weight/ m²) negatively affected the foraging of redshank, curlew and bar-tailed godwit but did not consistently affect oystercatcher. Redshank that fed on weed-covered areas had a reduced numerical food intake rate when compared to the birds on weed-free areas. During peak weed cover on the estuary, redshank on weeded areas had a 35.8% lower gross energy intake rate than those on weed-free areas.

Thesis (Ph. D.)--University of Oregon, 2008.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 100-104). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.

Agricultural nonpoint source pollution is recognised as a major cause of water pollution. The characteristics of nonpoint source pollution suggest that an efficient approach should focus on a source control and hence land-use management. Recently, the concept of Payments for Ecosystem Services (PES) has been advanced as an efficient market-based approach to protect in-stream water quality, while simultaneously supporting agriculture. Farmers can be rewarded for the adoption of certain ‘Best Management Practices’ (BMPs) in farming systems. But little is known about the adoption of BMPs in the context of Thai agriculture. This thesis examines the adoption of twelve BMPs on citrus farms in the Ping river basin in northern Thailand. In the context of potential PES development, three studies were undertaken using frameworks from economics and psychology. The first study used a bottom-up engineering approach to estimate economic costs of twelve BMPs at the farm-scale. The total annualised costs, including installation, maintenance, and land opportunity costs of each BMP were compared. The results indicated that land opportunity cost was the largest proportion of total costs. These estimates provided a basis for discussion on how the farmers’ perception of cost may influence their stated adoption intention. The second study used the Theory of Planned Behaviour (TPB), to investigate farmers’ intentions on adoption of twelve BMPs. A survey of 218 citrus farmers was undertaken in the application. Descriptive statistics and frequency of BMP selection were presented. The results showed that soil analysis was the most preferred BMP. A graphical analysis of other preferred measures suggested that these were not always consistent with the known cost information derived (above) and thus farmers’ perceived costs might not be the most important factor influencing adoption decisions. Further analysis based on TPB investigated other factors thought to be significant in farmers’ decision-making. Other potential external and psychological factors influencing adoption were investigated using a multinomial logistic model. The results indicated that the probability of adopting BMPs was associated with other psychological factors and external factors, rather than perceived costs. The significant psychological factors were farmers’ attitudes towards consumers and perception about farm returns, while the significant external factors were, for example, access to information and contribution of family labour to farm workload. The third study was based on the application of Q-Methodology, and aimed to obtain a deeper understanding of farmers’ perception towards BMPs. Seventy two participants were purposively selected from the 218 TPB observations. The results revealed four distinctive farmer groups holding different perceptions towards BMPs. The four groups were conservationist, traditionalist, disinterested, and risk-averse. These provided a specific segmentation to guide policy towards influencing attitudes and behaviours. The results suggested that farmers were not motivated solely by a profit maximisation goal. Overall, key findings from these three studies revealed some fundamental requirements for developing a water-related PES programme. These were: i) factors affecting eligibility to participate; ii) factors affecting desire to participate; and iii) factors affecting ability to participate. This information provided the basis for a set of recommendations addressing the development of the water-related PES programme in the Ping river basin.

Structural health monitoring is a very important phase of the maintenance of a civil work. In fact, thanks to the installation of a system able to monitor the conditions of a structure, it is possible to verify how this same structure responds to the loads to which it is subjected and to identify potentially damaged zones. Specifically, a railway bridge crossing a river undergoes stresses and deformations caused by the passage of trains, earthquake events and interactions with water. The INFRASAFE project aims to investigate all these aspects in order to guarantee a total monitoring of a specific structure - the bridge at Revere crossing Po river – in the environmental surrounding where it is placed. This research thesis is part of such project in a sense that it constitutes the preliminary analytical phase prior the experimental campaigns in the site. The truss structure will be modeled in Straus7 and a modal analysis will be performed in order to determine its frequencies and vibration modes. In addition, the axle loads of the real trains passing on the bridge will be considered for a linear static analysis. The results of such analysis will be investigated and the most stressed steel junction will be locally modeled in order to study its fatigue capacity.

The flathead catfish Pylodictis olivaris is a large piscivorous carnivore that has been widely introduced beyond its native range. I studied the behavior of a flathead catfish population that has recently inhabited a section of the Deep River, North Carolina (in the upper Cape Fear River basin), and currently coexists with the federally endangered Cape Fear shiner Notropis mekistocholas. This coexistence raises concerns of predation risks of the flathead catfish on the Cape Fear shiner. I radio-tagged 24 adult flathead catfish in the Deep River between Carbonton and Highfalls dams and monitored their behavior from June 2004 to August 2005. Fish were tracked weekly to determine seasonal patterns, and subsets of those were tracked once per hour for a 24-hour period to determine diel patterns. Eight of the fish were captured, tagged, and released in the upstream, shallow section of the river, and 16 in the deep, downstream, impounded section. A majority of the tagged fish either quickly moved into or stayed in the downstream, impounded section for the entire study period. Flathead catfish selected microhabitats non-randomly annually and within three functional seasons (spawning, growth, and winter). Flathead catfish were usually associated with habitats that were relatively deep (3-6 m), slow in velocity, over bedrock substrates, and nearly always in or adjacent to coarse woody debris or associated with no cover. Among seasons, these fish utilized different habitats, with faster bottom velocities during the spawning season, silt/clay substrates and faster mean column velocities in the growth season, and in the winter season, they occupied the deepest water available and most frequently, not associated with any cover type. I calculated estimates of seasonal home range as linear home range and kernel density estimates (99%, 95%, 90% and 50%). Flathead catfish mean linear home ranges were greater than 16 km annually, and mean seasonal ranges were 13.1 km during spawning, 10.1 km during growth, and 3.8 km in winter. Mean kernel density estimates of home range at 95% level were approximately half the linear estimate of home range annually and for each season. Mean kernel density estimates of home range at 50% (or core use) level were one-tenth of respective linear home ranges. On a diel scale, flathead catfish were generally more active and occupied deeper water at night. My findings on habitat use of adult flathead catfish at multiple spatial and temporal scales suggest the predation risk to Cape Fear shiners may be minimal, based on limited overlap. Furthermore, my results support other recent research describing flathead catfish as a highly mobile fish. These results add to our ecological understanding of this species in its introduced range and offer implications for improved management.

O presente trabalho teve como unidade de estudo a bacia hidrográfica do rio Cachoeira, localizada na vertente sul do Maciço da Tijuca, município do Rio de Janeiro. O objetivo geral do estudo foi analisar os efeitos das alterações na cobertura vegetal dessa bacia sobre seu comportamento hidrológico. As componentes hidrológicas selecionadas para análise foram a evapotranspiração real e a vazão média na exutória da bacia. Através do método do balanço hídrico de Thornthwaite e Mather, aplicado de forma sequencial, foi estimada uma série mensal de evapotranspirações reais da bacia. Foram utilizados nesse método de balanço hídrico dados de temperaturas médias do ar e totais precipitados na região. A série de vazões médias na exutória da bacia foi obtida utilizando-se como referência as estações fluviométricas Capela Mayrink e Itanhangá, ambas situadas no interior da bacia. Por meio de tecnologias de geoprocessamento e sensoriamento remoto foram mapeadas dez imagens do satélite Landsat-5/TM, estimando-se assim as alterações ocorridas na cobertura vegetal da bacia. Finalmente buscou-se estabelecer correlações entre as variações da cobertura vegetal e das componentes hidrológicas selecionadas. O resultado obtido para a evapotranspiração real foi satisfatório, indicando uma relação direta com a dinâmica da cobertura da bacia. Entretanto não foi possível estabelecer para a vazão média uma correlação de qualidade semelhante. Através desse estudo adquiriu-se um melhor entendimento sobre a influência da variação da cobertura vegetal no comportamento hidrológico da bacia hidrográfica do rio Cachoeira.
The general objective of the study was to analyze the effects of land cover changes on hydrological processes of the Cachoeira river watershed. The hydrological components selected for analysis were the real evapotranspiration and the mean flow at the exutory of the watershed. Through the Thornthwaite and Mather water balance method, applied sequentially to the period between 1997 and 2010, a monthly series of real evapotranspiration was established. The choice of this method was based on the compatibility of the data required by the method with the hydrometeorological available data. Monthly series of average air temperatures and total precipitations was used to calculate the water balance of Thornthwaite and Mather. The average air temperature data were obtained from the pluviometric station Alto da Boa Vista, located around the watershed. In order to obtain a complete and consistent data series of average air temperatures, a correlation was established of these data with the data from the climatological station of the city of Rio de Janeiro. Through this correlation was possible to confirm the consistency of the series of air temperatures and fill any gaps from 1997 until the year 2010. In this period the monthly series of average air temperatures had a mean of 22,1 Celsius degrees, ranging from a maximum of 27,5 Celsius degrees and a minimum of 17,8 Celsius degrees. The pluviometric data used as reference for the average rainfall over the Cachoeira river watershed, was recorded at the pluviometric station Capela Mayrink, located within the watershed. The consistency of this series has been verified before the other pluviometric stations around the watershed by the method of the double mass, which could confirm the consistency because no deviations were found in the precipitation behavior over time. The average annual precipitation over the watershed was 2.181 mm. The highest estimated values of real evapotranspiration were found in the rainy season, between December and March. The estimated average value of annual real evapotranspiration during the studied period was 1.056 mm, ranging between 1.007 mm and 1166 mm. This average value corresponds to approximately 50 per cent of total annual precipitated, in other words, it is indicated that half of the precipitation over the watershed would return to the atmosphere by the processes of the hydrological cycle. Besides the real evapotranspiration, the water balance also provided an estimation of the water extract of the watershed, calculating components as water deficit, water surplus and soil water storage. The mean monthly flow series at the exutory of the watershed was obtained by referencing the data recorded at the fluviometric stations Capela Mayrink and Itanhangá, both located within the watershed. The data from these stations have gone through a consistency analysis, where their fluviometric levels were verified together and their rating curves were elaborated to represent an adequate adjustment to their liquid discharge measurements. After the consistency analysis, the fluviometric levels data were transformed into flows, through the rating curves. The methodology adopted to generate the flow series at the exutory of the watershed consisted primarily in the extension of the flows series at Itanhangá station through correlation with the flows at Capela Mayrink station. Subsequently, the extended flow series at Itanhangá station was transferred to the exutory location by proportionality between drainage areas. Due to the lack of local data, it was not possible to obtain a mean monthly flow series without gaps. The comparison of the flow data with the precipitation data, obtained for the Cachoeira river watershed, showed a coherent behavior over the years. The annual variation of rainfall in the watershed was accompanied by the flow. It was possible to estimate the changes in land cover during the period from 1988 to 2010 using geoprocessing and remote sensing technologies, available at the extension Spatial Anal

Individer som utövar någon typ av sport utsätter sig för både psykiskt och fysisk påfrestning. Denna påfrestning kan vara något som stressar individen och måste därför hanteras och bemästras på något sätt.  Syftet med studien var att undersöka vad som motiverar hobby- respektive professionella ryttare, finns det någon skillnad i upplevelsen av motgångar i sin sport mellan hobbyryttare och professionella tävlingsryttare, och om grupperna har olika sätt att bemästra motgångar. Deltagarna var 11 kvinnor, fem professionella ryttare och sex hobbyryttare. Analysen gjordes genom meningskoncentrering, där olika teman utformades efter studiens frågeställningar. Resultatet visade bland annat på att hobbyryttarna använde sig utav undvikande bemästrande strategi i större utsträckning än vad de professionella ryttarna gjorde. Detta skulle kunna bero på att professionella ryttare använde sig mer utav problemfokuserad bemästrandestrategier därför att de hade mer rutin och kunskap inom sporten än hobbyryttarna hade.

Larval, pupal and adult samples of Culoptila cantha, from a large riffle of the Brazos River in north-central Texas from January, 1995 to March, 1997, indicated a predominately trivoltine cycle during both years; the over-wintering generation spanned 6-7 months and warm-season generations spanned 2-3 months. Eggs, larvae of all instars, larval cases, case reconstruction progression and behavior, pupae, and adults are described.

Threespine stickleback (Gasterosteus aculeatus) and juvenile chinook salmon (Oncorhynchus tshazvytscha) co-occur during high tide in tidal channels of the Fraser River estuary. Given the high density of resident stickleback, there is the potential for strong interactions within and between the two species. Inter- and intra-specific interactions were tested by means of laboratory experiments, with support from field studies. Laboratory experiments placed stickleback and chinook in mixed and single species groups. The levels of aggressiveness were quantified, along with prey choice between surface (Drosophila), midwater (Artemia), and benthic (Tubifex) prey; microdistribution was also recorded. The experiments demonstrated that stickleback were highly aggressive towards chinook, and would drive them away from optimal feeding territories. Chinook consumed surface prey only when tested with stickleback, exploiting benthic and midwater prey when feeding alone. Stickleback demonstrated no significant difference in diet between single and mixed species trials, which is consistent with the supposition of strongly asymmetrical competition for food and space. Field data lend further support to this premise; a marked difference observed in diet suggests microhabitat partitioning between the two species, with stickleback feeding on benthos and chinook largely consuming surface prey. This thesis proposes that interactive segregation is an important process between sympatric stickleback and juvenile chinook in estuarine tidal channels and might have important implications for Fraser chinook stocks.
Science, Faculty of
Zoology, Department of
Graduate

Anthropogenic influences on riverine ecosystems have led to numerous impacts that have compromised fish communities. Large European lowland rivers have been amongst the most impacted aquatic environments globally. However, paradoxically, these environments have also been amongst the least studied, due the inherent difficulties of studying fish in large, turbid, dynamic environments. Common bream Abramis brama (L.) populations are amongst those impacted by reduced lateral and longitudinal connectivity that are a consequence of modifications to large lowland rivers in Europe. Thus common bream in the lower River Witham, Lincolnshire, UK, were selected as a case study to examine how fish utilize these river systems. A literature review was carried out to assess the influence of human intervention on riverine ecosystems and their impacts on fish communities. In addition the use of telemetry techniques for studying fish populations was reviewed. An ecological assessment of the lower River Witham was carried out using data available from The Environment Agency monitoring and hydrological systems and data specifically collected during this study. The history of this highly modified lowland river was reviewed to give perspective, timescale and context to the degree of modification that has been undertaken on the river and its consequences. Chemical and biological water quality indicators showed improvements in the last twenty years. Fisheries data identified three species that had become locally extirpated in the lower river since the 1800s. The river is now roach dominated, but common bream are still present, possibly due to available lateral spawning habitats that provide surrogates for, and are functionally similar to, the lentic floodplain waterbodies of natural riverine ecosystems. Hydroacoustic surveys show that fish communities are aggregated and favour the upstream half of the lower river where the channel is more heterogeneous. Recent changes in river character have made traditional fishery assessments by seine netting less effective. Data collected during fish tracking studies are most valuable when the tagged fish are behaving naturally, thus the effects of tag attachment should not impact on the behaviour or well being of the fish. Acoustic telemetry was used to investigate the impacts of tagging, surgical inter-peritoneal implantation, and translocation of common bream. Fish were recaptured following surgery and the incision site photographed to assess healing, which was clean in all cases. All recaptured fish appeared to be behaving normally as they were part of large shoals of fish. On five separate occasions fish were tagged when other previously tagged fish were present allowing their behaviour to be compared in terms of the distances moved and linear range; there were no significant differences between the two groups indicating the tagging procedure to have no detectable impact on the short-term behaviour of the fish at the resolution of the tracking undertaken. Three recaptured fish were translocated ~35 km downstream; these fish appeared to exhibit homing behaviour, returning to the capture site between 6-24 days. Their level of activity (in terms of distance moved) did not significantly differ from non-translocated fish, but their linear range was larger. The distribution and habitat use of adult common bream was assessed by tracking their longitudinal and lateral movements over forty-three months, producing a dataset of over 3.1 million detections. A positive relationship between activity and temperature was revealed, with common bream moving greater cumulative distances during the warmer months and occupying a greater longitudinal proportion of the main channel. The occupancy of tributaries was related to temperature, with common bream entering shallow tributaries during rising temperatures in the spring, whilst a deeper, slow-flowing tributary was used more frequently during the cooler autumn/winter months. During the autumn, occupancy of this deeper tributary was positively related to flow rate, suggesting that common bream use this as a refuge from high main channel flow. The home range concept is at the centre of theoretical models to explain the spatio-temporal behaviour of a wide range of animals including fish. There are lots of different ways of expressing home ranges, including areas, but since rivers are principally linear systems, most range is reflected linearly. Home ranges were calculated for 100% and 90% of locations. Seasonal differences were identified with fish occupying larger home ranges during the spring and summer opposed to autumn and winter. Artificial water level manipulations, management actions for the control of flood risk, affected home range size with fish occupying smaller ranges at reduced winter levels than at increased summer levels. Analysis of when and how often individuals within a population interact with one another provides a method to study the social organisation of animals with the potential to reveal ecologically significant aspects that would otherwise have remained hidden. Network analysis and social network theory were used to examine the social interactions of the tracked fish. The extent of sociality appears to follow a normal distribution, such that there was no evidence of discrete classes of social/non-social fish. Fish were more social immediately after tagging and less social as time progressed, as such little evidence could be found to support the hypothesis that these groups of fish remained in each others’ company for extended periods. However, more active individuals were found to be more socially connected, but home-range size did not significantly affect sociality. The functions of these behaviours are discussed along with potential management and rehabilitation strategies for the lower River Witham and other heavily modified lowland rivers in order to meet good ecological potential/status under the Water Framework Directive (2000/60/EEC).

>Magister Scientiae - MSc
The analysis of what controls why rivers are the way they are, and how and why they change is crucial in predicting river dynamics and deriving classification systems that can assist management. A variety of factors control the pattern of fluvial styles in a river system across spatial scales. The geomorphic response of a river to an individual control, such as stream power for example, will vary due to a combination of other contributing factors such as geology and climate.

In many rivers, dams have interrupted the connectivity of migration routes for fish. While fishways can provide access between downstream and upstream habitats, it is important that passage can occur with minimal delay, energy expenditure, and physiological stress. The research presented here is based on investigations into fishway attraction and passage for the Gates Creek sockeye salmon (Oncorhynchus nerka, Walbaum) stock at the Seton River dam in British Columbia. The first part of this thesis examined the effect of changes in water discharge from the dam on the relationship between the physiological condition of sockeye and their behaviour in approaching the fishway entrance. Fish were caught and non-lethally biopsied under three normal operating discharge conditions at Seton River dam, and subsets of sampled fish were implanted with radio transmitters and released downstream of the dam. Indices of physiological stress and exhaustive exercise (e.g. plasma cortisol, glucose, lactate, osmolality and hematocrit) did not differ among the water discharge levels that were examined. Fish delayed in the tailrace below the fishway entrance significantly longer under intermediate discharge (19.9 h @ 12.7 m³s‾¹) than either the high discharge (9.3 h @ 15.8 m³s‾¹), or the low discharge (7.0 h @11.0 m³s‾¹;) conditions (P = 0.022, and P = 0.015, respectively). Delay time was similar under high and low discharge conditions (P = 0.617), and passage success was found to be independent of discharge (P = 0.356). The second part of this thesis investigated how prior physiological condition and subsequent swimming energetics and behaviours effected fishway passage success. Fish were captured and biopsied, before being implanted with electromyogram (EMG) transmitters and released near the downstream entrance of the fishway. Very few differences existed between successful and unsuccessful fish in body size, initial plasma physiology and energy state, and mean swim speed and energy use during passage. However, plasma Na+ concentration was significantly lower in unsuccessful fish (P = 0.022), which is suggestive of a depressed ionic state for unsuccessful fish. Generally, fish did not employ burst swimming during successful or failed attempts at passage, indicating that failure was probably not related to metabolic acidosis.

A reach of Peace River between Fort St. John and Hudson’s Hope flows in a steepsided valley cut by meltwater and Holocene river flow through Cretaceous shale and sandstone covered by clay‐rich glaciolacustrine deposits. Numerous landslides occur on the banks, initiating in both the bedrock and overburden. Following a recently completed local landslide inventory and the completion of an airborne LiDAR survey, five landslides have been examined in detail: the Attachie Slide, the Moberly River Slide, the Halfway River Slide, the Cache Creek Slide and the Tea Creek Slide. Analysis of the five case studies suggests that most slope movements can be attributed to one of four dominant landslide failure mechanisms: compound rock slides, compound overburden slides, shallow rapid flow slides, and earth flows. Compound slides in bedrock and overburden are morphologically similar. Most have the character of compound slides, exploiting weak horizontal clay layers found at multiple levels in both materials. Typically, a sliding surface develops along a bedding plane presheared to residual friction and connects to a steep main scarp cross cutting the layers of rock and soil. Frequently this mechanism then repeats successively at multiple levels. The Cache Creek Slide and Tea Creek Slide are examples of compound slides in bedrock. The Moberly River Slide and the Attachie Slide are examples of compound slides in overburden. The toes of the slide deposits often assume the character of earth flow tongues which are intermittently removed by river erosion. Shallow rapid flow slides, such as the Halfway River Slide, are also common in the normally consolidated glaciolacustrine silts and clays of Glacial Lake Peace that overlie the study area.

Fishes are widely used by biologist as ecological indicators that measure key elements of complex systems, without having to capture the full complexity of a specific system. The Vaal River in South Africa is classified as Africa’s hardest working river and is home to, two yellowfish species that are socially and economically important. Both these yellowfish species are considered to be sensitive to changes in water quantity and quality, habitat destruction and utilisation pressure and are often used as ecological indicators to manage aquatic ecosystems. Very little however, is known about their movement, response to changing environmental variables and interspecies habitat preferences. This study therefore aims to use radio telemetry as a method to characterise and evaluate how yellowfish behaviour is influenced by changing environmental variables. To characterise the behavioural ecology of the Vaal-Orange River yellowfish species in lentic and lotic ecosystems, Labeobarbus aeneus (n=18) and L. kimberleyensis (n=3) were fitted with externally attached radio transmitters in Boskop Dam (L. aeneus, n=4) and the Vaal River (L. aeneus, n=14) (L. kimberleyensis, n=3). Various methods were used to collect yellowfish species including: gill nets, to target mobile individuals, in deep habitats, electro-fishing (electro-narcosis) to collect yellowfish in shallow habitats and angling techniques in a wide variety of habitats. Thereafter yellowfish species were sedated and tagged with externally attached radio transmitters, before being released back into the system. Yellowfish were monitored for eleven months using a remote monitoring system together with manual monitoring surveys. Analyses of data collected showed that L. aeneus follows distinct behavioural patterns, with some individual variations in behaviour. Labeobarbus aeneus exhibited higher movement that are associated with deeper water during daylight hours (04:00-16:00). During nocturnal periods (20:00-04:00) L. aeneus showed a decrease in movement activity and preferred shallower water compared to daytime. However, L. aeneus in the Vaal River seems to be less influenced by bright daylight and this might be due to the turbidity of the river water. Labeobarbus aeneus in Boskop Dam showed higher movement counts during full moon phases whereas L. aeneus in the Vaal River showed higher movement counts during new moon phases. All tagged fishes in Boskop Dam and in the Vaal River preferred deeper water during full moon phases than during new moon phases. Movement were significantly higher (P<0.05) with increased temperatures and shallower water in summer whereas movement significantly decreased (P<0.05) with a decrease in temperature and increased depth in autumn and winter. Seasonal movement data were, however, limited. This study confirms that radio telemetry methods can be used to characterise the behavioural ecology of yellowfish species. In addition, the study has improved the knowledge of how environmental variables may affect the behaviour of yellowfish species. However, due to limited data and our understanding of these species, it is still uncertain how behaviour of yellowfish species can be applied as an ecological indicator of aquatic ecosystems.
Thesis (MSc (Zoology))--North-West University, Potchefstroom Campus, 2013

This dissertation focuses on (river) forecasting, but also includes a study on stormwater treatment. Using forecasts for decision-making is complicated by their inherent uncertainty. An interview-based study qualitatively and a survey empirically investigate forecast use in emergency management. Emergency managers perceive uncertainty as a given rather than as a problem. To cope with the uncertainty, decision-makers gather as much information as possible; forecasts are only one piece of information among many. For decision-making, emergency managers say that they rely more on radar than on river forecasting. However, forecasts play an important role in communication with the public, because they are the official interpretation of the situation. Emergency managers can add a lot of value to those forecasts by combining them with local knowledge, but might not do so because of accountability concerns. Forecasts must have value to emergency managers, because those with more work experience rely more on them than those without. Another study further develops the application of quantile regression to generate probabilistic river forecasts. Compared to existing research, this study includes a larger number of river gages; includes more independent variables; and studies longer lead times. Additionally, it is the first to apply this method to the U.S. American context. It was found that the model has to be customized for each river gage for extremely high event thresholds. For other thresholds and across lead times, a one-size-fits-all model suffices. The model performance is robust to the size of the training dataset, but depends on the year, the river gage, lead time and event threshold that are being forecast. An additional study considers the robustness of stormwater management to the amount of runoff. Impervious surfaces, such as roads and parking lots, can increase the amount of runoff and lead to more pollution reaching streams, rivers, and lakes. Best Management Practices (BMPs) reduce the peak discharge into the storm sewer system and remove pollutants such as sediments, phosphorus and nitrogen from the stormwater runoff. Empirically, it is found that BMP effectiveness decreases sooner, steeper and deeper with increasing sizes of storm events than assumed in current computer models.

I conducted demographic and behavioral studies of Western Sandpipers (Calidris mauri) breeding on the Yukon-Kuskokwim River Delta, Alaska (1998-2005). In chapter one, I estimated apparent annual survival (product of true survival and site fidelity) while correcting for the probability of encounter for 237 males and 296 females. Overall return rates (individual returned to the site in a subsequent season) were lower for females (40%) than males (65%), as was apparent annual survival (± SE, females = 0.65 ± 0.05, males = 0.78 ± 0.03), and encounter rate (females = 0.51 ± 0.07, males = 0.74 ± 0.04). In chapter two, I examined the effects of mate and site fidelity on nesting success (N = 430 nests). Annual divorce rate ranged between 37-83%, with 17-63% of pairs reuniting annually. Reuniting pairs initiated clutches earlier than newly formed pairs, and clutches that were initiated early in the season had higher nest success rates compared to late-season nests. When I controlled for clutch-initiation date, nests tended by individuals with prior breeding-site experience had higher daily survival rates compared to birds breeding at the site for the first time. The effect of site experience was greater for males than females. In chapter 3, I reported that Western Sandpipers exhibited aggregated breeding behavior on a 36 ha plot. Breeding aggregations occurred when dominant and/or older individuals excluded younger, subordinate individuals from preferred habitat. The pattern of habitat occupancy conformed to an ideal despotic distribution with aggregated nesting birds in less preferred habitat experiencing lower reproductive success. In chapter 4, I described and demonstrated the form and function of parent-chick communication in the Western Sandpiper. Through experimental playback of adult vocalizations to chicks in the field, I demonstrated: (1) chicks respond to the alarm call by vocalizing relatively less often and moving away from the signal source, (2) chicks respond to the gather call by vocalizing relatively more often and moving toward the signal source, (3) and chicks respond to the freeze call by vocalizing relatively less often and crouching motionless on the substrate for extended periods of time. I also describe two distinct chick vocalizations (chick-contact and chick-alarm calls).
Ph. D.

The tidal James River, a focus of VCU's Atlantic Sturgeon program, supports both commercial shipping and hydraulic dredging. These anthropogenic threats present documented but preventable sources of mortality to the endangered species. Using three separate VEMCO Positioning System (VPS) receiver arrays, spatial data of previously-tagged fish were collected. ArcGIS and Programita software were used to analyze fish spatial distributions in the presence and absence of potential threats, using additional data including automatic identification system (AIS) vessel locations, vessel passages compiled using camera footage, and dredge records provided by the US Army Corps of Engineers. The data showed a change in distribution associated with vessels that varied according to river width but not vessel type. Dredging was associated with differences in spatial distribution, but more clearly for adults than sub-adults. The responses of Atlantic Sturgeon provide information necessary to propose potential threat mitigations, including seasonal restrictions for both vessels and dredging.