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This study proposes a stratified approach of drought severity assessment using multi-layer simulated soil moisture. SWAT (Soil and Water Assessment Tool) models are calibrated for 50 watersheds in the South-Atlantic Gulf region of the Southeastern US and a high-resolution daily soil moisture dataset is obtained at Hydrologic Unit Code (HUC-12) resolution for a period of January 1982 through December 2013. A near real-time hydrologic simulation framework by coupling the calibrated SWAT models with the National Centers for Environmental Prediction (NCEP) coupled forecast system model version 2 (CFSv2) weather data is developed to forecast various water balance components including soil moisture (SM), actual evapotranspiration (ET), potential evapotranspiration ET (PET), and runoff (SURQ) for near-real time drought severity assessment, and drought forecasting for a lead of 9-months. A combination of the surface and total rooting depth soil moisture percentiles proves to be an effective increment over conventional drought assessment approaches in capturing both, transient and long-term drought impacts. The proposed real-time drought monitoring approach shows high accuracy in capturing drought onset and propagation and shows a high degree of similarity with the U.S. Drought Monitor (USDM), the long-term (PDSI, PHDI, SPI-9 and SPI-12), and the short-term (Palmer Z index, SPI-1 and SPI-6) drought indices. / Master of Science

This study, conducted at Camp Pickett, Virginia, attempted to evaluate several rabbit management practices currently in use on this deactivated military reservation. The methods being applied by the Virginia Come mission of Game and Inland Fisheries consist of establishment of wildlife food plots, the seeding of fire lanes and mowing and burning as a means of retarding ecological succession. Results of these evaluations indicated that the annual mixture plot is the type most heavily utilized by rabbits during the fall. Next in importance was the clover-winter grain combination planting. These conclusions were determined by means of live trapping and these trapping data were substantiated by pellet counts. A total of 211 rabbits were handled in this phase of the study; 135 were marked and 76 were recaptured. Of the 135 animals marked, 40.8 per cent were marked in the annual mix plots. This trapping demonstrated a sex ratio of 130 males to 100 females and an immature to adult female ratio of 2.3:1. A relationship between trapping success and temperature seemed to exist; a coefficient of correlation of -0.273 was calculated. A vegetative inventory inferred that both mowing and burning may be desirable rabbit management practices. An attempt was made to test three population estimation formulae on a known, enclosed rabbit population. Results of trapping within the five acre enclosure gave a comparable population estimate fer the Lincoln index, the Krumholz formula and the Schumacher-Eschmeyer formula. This experiment was not carried to the refined point of supplying definite conclusions; further investigation is necessary before concrete recommendations may be made. Records of the hunting season harvest were maintained. When these kill figures were combined with a rough estimate of the rabbit population on Camp Pickett, it was indicated that approximately 26 per cent of the cottontails were harvested. Hunting kill records maintained by the Game Commission over the past three years show a marked increase in hunter success, probably due te the effects of management. All bot fly parasitism cases were noted; 155 infestations were observed among the 325 rabbits handled. The larvae demonstrated no preference as to sex of the host but immature cottontails were more heavily parasitized than were adults, Records of tularemia incidence throughout Virginia have been maintained. Two areas of greater incidence occur; however, the Camp Pickett area appears to be average for the state. Cost comparisons were made between annual mix plots and clover-winter grain plots. The annual mix type of food plot cost an estimated $7.30 per half acre te install; the clover plot cost $18.09 per half acre. Which type plot, annual or perennial, is used depends upon the budget and Labor available. The writer favors use of the clover plots for rabbits both from the economical and biological points of view. / Master of Science

Thesis (MFor)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: The factors determining habitat selection of large herbivores, on a private wildlife reserve in semi-arid southeastern Zimbabwe, were investigated. Gross vegetative structure, herbaceous composition and topographic features thought to determine herbivore distribution were measured. Seasonal variation in resource distribution was considered, and research therefore extended over an entire year. Herbivore distribution and ecological niche separation was explained through several important environmental variables, and potential for inter-specific competition inferred. Additionally, predictive habitat suitability models were designed for each of the grazing species in the critical dry season. Herbivores showed a large degree of niche overlap in both the hotwet season and the cool-dry season, when food resources were more plentiful. Niche separation between grazers was pronounced in the hot-dry season. Herbivore distribution was associated most closely with distance to water, grass sward height, time since burn, woody plant density and by the presence of predominant grasses, these being Urochloa mossambicensis, Panicum maximum, Heteropogon contortus and Digitaria eriantha. Ecological separation of herbivores by the grasses P. maximum, H. contortus and D. eriantha was more indicative of associated environmental variables than feeding niche separation. A GIS-based analysis, using species presence data and quantitative coverages of environmental variables, produced maps of gradations of habitat suitability for grazing species during the dry season. Results of both analyses were integrated and gave a better understanding of ecological separation, and possible competitive interactions, among the large herbivore community on Malilangwe Estate. Recommendations were made based on the interpretation of findings, within the context of available management options. / AFRIKAANSE OPSOMMING: Die bepalende faktore van habitat seleksie by groot herbivore op ‘n privaat wildreservaat in semi-dorre suidoos Zimbabwe is ondersoek. Globale plantegroei stuktuur, kruidagtige samestelling en topografiese eienskappe wat glo herbivoor verspreiding bepaal, is gemeet. Seisoenale variasie in hulpbronverspreiding is in ag geneem en dus het navorsing oor ‘n hele jaar gestrek. Herbivoor verspreiding en ekologiese nisskeiding is verduidelik deur verskeie belangrike omgewingsveranderlikes en die potensiaal vir interspesifieke kompetisie is afgelei. Boonop is voorspellende habitat-geskiktheidsmodelle ontwerp vir elk van die weidingspesies in die krities droë seisoen. Herbivore toon ‘n hoë graad van nis oorvleueling in sowel die warm, nat seisoen as die koel, droë seisoen wanneer voedingsbronne meer volop is. Nis verdeling tussen weidiere was duidelik herkenbaar in die warm, droë seisoen. Herbivoor verspreiding is meestal geassosieer met die afstand na die water, die grasveld hoogte, tydperk sedert ‘n brand, digtheid van houtagtige plantsoorte en met die teenwoordigheid van die oorheersende grasse, Urochloa mossambicensis, Panicum maximum, Heteropogon contortus en Digitaria eriantha. Die ekologiese skeiding van herbivore deur die grasse P. maximum, H. contortus en D. eriantha het meer gedui op geassosieerde omgewingsveranderlikes as op skeiding van voedingsnisse. ‘n GIS-gebaseerde analise wat spesie-teenwoordigheidsdata en kwantitatiewe dekking van omgewingsveranderlikes gebruik, het klassifikasiekaarte geproduseer van habitatgeskiktheid vir weidiere tydens die droë seisoen. Resultate van beide analises is geïntegreer en het ‘n beter begrip van ekologiese skeiding en moontlike kompeterende interaksies tussen die groot herbivore gemeenskap op Malilangwe Estate tot gevolg gehad. Aanbevelings is gemaak, gebaseer op die interpretasie van bevindinge, binne die konteks van beskikbare bestuursopsies.

Thesis (MSc)--University of Stellenbosch, 1989. / AFRIKAANSE OPSOMMING: Senosoiese sedimente langs die suidooskus van die Kaapprovinsie is periodiek deur verskeie outeurs vir meer as 'n eeu bestudeer. In hierdie aanbieding word die Iiteratuur saamgevat en vele dubbelsinnige stratigrafiese onderverdelings en definisies opgeklaar. Die Senosoiese afsettings kan volgens oorsprong geklassifiseer word as marien, eolies en fluviaal. Die mariene afsettings, synde strand-, nabystrand-, estuarien of lagunale afsettings geassosieerd met transgressiewe/ regressiewe kusIyne, word nou op grond van kenmerkende litologiese, paleontologiese sowel as ouderdomsverskille onderverdeel in die Paleogeen Bathurst, Neogeen Alexandria en Kwaternere Salnova Foraasies. Die Laat-Plioseen tot Vroeg-Pleistoseen Nanaga Formasie, Middel- tot Laat- Pleistoseen Nahoon Formasie en die Holoseen Schel• Hoek Formasie vorm die kus-eoliese afsettings. AI die mariene en marienverwante (eoliese} formasies, gekenmerk deur kalkige klastiese afsettings, is saamgegroepeer in 'n nuutgedefinieerde Algoa Groep. Fluviale afsettings word onderverdeel in die Martindale, Kinkelbos, Bluewater Bay, Kudus Kloof en Sunland Formasies. Die onderskeie afsettings word gekorreleer met verskillende seevlakstande deur geologiese tye. Die vroegste Senosoiese transgressiewe/regressiewe siklus het in die Vroeg-Paleoseen begin en die hoogste aangetekende elevasie vir die era bereik. Die Bathurst Formasie is waarskynlik gedurende hierdie regressie afgeset. 'n Tweed~ kleiner transgressie/ regressiesiklus het plaasgevind gedurende die Laat-Eoseen tot Vroeg-Oligoseen. Sover tans bekend, kan geen afsetting in die dagsoomgebied van die Algoa Groep definitief met hierdie siklus in verband gebring word nie. Die volgende siklus, wat 'n transgressiewe maksimum van c. 250 m bereik het, het begin in die Middel-Mioseen en verstryk in die Vroee Plioseen. Mariene planasie van die kusplatform het gedurende die transgressie plaasgevind terwyl die Alexandria Formasie wat tans bo 120 m geleë is, gedurende die regressie afgeset is. Die Vroeg-Plioseen transgressie het waarskynlik 'n maksimum huidige hoogte van c. 120 m bereik, waartydens o.a. die 120 m branderstoep en "Humansdorpterras" gekerf is. Die Alexandria Formasie tans geleë tussen 60 en 120 m, is afgeset gedurende die Laat-Plioseen regressie. Hierdie regressie het verskeie relatief lang stilstande, wat waarskynlik die 106-m, 90- tot 100-m en 84-m branderstoepe verklaar, ondervind. Selfs die 60-m en 52-m kuslyne kon tydens hierdie regressie gevorm het. Voorlopige paleontologiese getuienis dui egter daarop dat die 60-m kuslyn 'n transgressiewe maksimum van 'n daaropvolgende siklus verteenwoordig, gevolg deur 'n regressie met minstens een beduidende stilstand by 52 m. Die Alexandria Formasie geleë tussen c. 60 en 30 m, is waarskynlik gedurende hierdie regressie gedeponeer, waartydens ook die Bluewater Bay, Kinkelbos en Kudus Kloof Formasies afgeset is. Gedurende die Kwaternêre transgressie/regressiesiklusse, waarvan minstens vier aangedui word, is die Salnova Formasie (afwesig bo 30 m) afgeset. Die Nahoon Formasie, wat ook op groot skaal op die kontinentale bank ontwikkel is, is gedeponeer gedurende die laaste twee Pleistoseen glasiale toe seevlakke tot benede -100 m gedaal het. Die Schelm Hoek Formasie wat tans nog afgeset word, het ontstaan uit die transgressiewe maksimum van die Flandriese transgressie aan die begin van die Holoseen. / ENGLISH ABSTRACT: Cenozoic sediments along the south-east coast of the Cape Province have been studied intermittently for more than a century by various authors. In this presentation the literature is reviewed and many ambiguous stratigraphic subdivisions and definitions are clarified. The Cenozoic deposits can be classified, according to origin, as marine, aeolian and fluvial. The marine deposits, being lagoonal deposits either beach, nearshore, estuarine or associated with transgressive/regressive shorelines, are now subdivided on the grounds of distinct lithological, palaeontological as well as age differences into the Palaeogene Bathurst, Neogene Alexandria and Quaternary Salnova Formations. The Late Pliocene to Early Pleistocene Nanaga Formation, the Hiddle to Late Pleistocene Nahoon Formation and the Holocene Schelm Hoek Formation constitute the coastal and marine-related aeolian deposits. All the marine (aeolian) formations, which are characterised by calcareous clastics, have been grouped together in a newly defined Algoa Group. Fluvial deposits are subdivided into the Martindale, Kinkelbos, Bluewater Bay, Kudus Kloof and Sunland Formations. The various deposits are correlated with different stands of sea-level through geological time. The earliest Cenozoic transgression/regression cycle started in the Early Palaeocene and reached the highest recorded altitude for the era. The Bathurst Formation was probably deposited during this regression. A second lesser transgression/regression cycle occurred in the Late Eocene to Early Oligocene. As far as is presently known, no deposit in the outcrop area of the Algoa Group can be definitely related to this cycle. The next cycle, which reached a transgressive maximum of c. 250 m, started in the Middle Miocene and terminated in the Early Pliocene. Marine planation of the coastal platform took place during the transgression, whilst the Alexandria Formation presently situated above 120 m, was deposited during the regression. The Early Pliocene transgression is considered to have reached a maximum present-day elevation of c. 120 m, during which the 120 m marine bench and "Humansdorp Terrace", amongst others, were carved. The Alexandria Formation presently situated between 60 and 120 m, was deposited during the Late Pliocene regression, which experienced several relatively long stillstands which probably account for the 106 m, 90 t.o 100 m and 8.4 m benches. Even the 60 m- and 52 m-shorelines could have been formed during this regression. Preliminary palaeontological evidence, however, suggests that the 60 m shoreline represents a transgressive maximum of a subsequent cycle followed by a regression with at least one significant stillstand at 52 m. The Alexandria Formation situated between c. 60 and 30 m, was probably deposited during this regression, which also saw the deposition of the Bluewater Bay, Kinkelbos and Kudus Kloof Formations. During the Quaternary transgression/regression cycles, of which at least four are indicated, the Salnova Formation (absent above 30 m) was deposited. The Nahoon Formation, which is also extensively developed on the continental shelf, was deposited during the last two Pleistocene glacials, when sea-levels receded to less than -100 m. The Schelm Hoek Formation, which is still being deposited, originated from the transgressive maximum of the Flandrian transgression at the start of the Holocene.

The self-recruiting species (SRS) are aquatic animals that can be harvested regularly from a farmer managed system without regular stocking as described by Little (2002a, b). The potential and current role of self-recruiting species from farmer managed aquatic systems (FMAS) is often overlooked, whilst much attention has been given to stocked species (often associated in conventional culture ponds and cages) as well as the fisheries sector (often relates to large water bodies i.e. river lakes and reservoirs). Using the combination of qualitative and quantitative research approaches, the current status, the important contribution of SRS and factors undermining this contribution to the livelihoods of rural households in mainland Southeast (SE) Asia were investigated. The overall analysis of this research was done based from the sustainable livelihood (SL) framework (Scoones, 1998; DFID, 1999) in order to have a broader understanding of the importance of SRS as well as the rural livelihoods in selected areas of mainland SE Asia which often benefit from this resource. The research was carried out in rural villages of southeast Cambodia (SEC), northeast Thailand (NET) and Red River Delta in northern Vietnam (RRD). The sites (region of the country) were selected based from the intensity of aquaculture practices (less established and mainly relying on natural production, aquaculture established but also relying on natural production and mainly aquaculture dependent) as well as the agriculture i.e. intensiveness of rice production. Eighteen villages (6 villages/ country) were selected to represent the two agro-ecological zones (i.e. LOW and DRY areas) of the study sites. In order to fully assess the situation and meet the objectives of the research, the study was carried out using three stages which dealt with different approaches and sets of participants/respondents; i) participatory community appraisal (PCA), ii) baseline survey and iii) longitudinal study. The different stages of the research were carried out during the period of April 2001 until September 2004. During the first stage, a series of community appraisals using participatory methods were conducted in all of the participating villages in the three study sites. The participatory appraisal was conducted in order to understand the general rural context in the villages as well as the importance of aquatic resources. Moreover, the PCA in a way helped build rapport between the researcher and the communities. The series of appraisals were conducted with different wellbeing and gender groups (better-off men, better-off women, poor men and poor women). The various shocks, trends and seasonality that influenced the status of living in the community, diversified livelihoods and the differences in preference of socioeconomic and gender groups were analysed in this stage. The important aquatic animals (AA) and the local criteria for determing their importance were the highlights of this stage of the research. The important AA identified were composed of large fish (Channa spp., Clarias spp., Hemibagrus sp, Common, Indian, Silver and Grass carps), small fish (Anabas testudineus, Rasbora spp., Mystus spp., Carassius auratus) as well as non-fish (Macrobrachium spp., Rana spp., Somanniathelpusa sp., Sinotaia spp.) which were particularly important to poorer groups in the community. The local criteria used were mainly food and nutrition related (good taste, easy to cook, versatility in preparation), abundance (availability, ease of catching) as well as economic value (good price). Significant differences were found between various interactions of sites, agro-ecological zones, gender and wellbeing groups. The second stage of the research was the baseline survey (cross-sectional survey) which was also carried out in the same communities and collected information from a total of 540 respondents (30 respondents per village or 180 per country). This stage of the study was carried out in order to generate household level information (mostly quantitative) regarding the socio-economic indicators to triangulate the information generated during the participatory appraisal and the different aquatic systems that existed in the community as well as the various management practices used (not limited to stocking hatchery seed and feeding). The different livelihood resources (human, physical, financial, natural and social capital) and the diversified strategies of rural households in SE Asia were analysed in this phase. Another highlight of this phase was the understanding of the various aquatic systems that rural farmers managed and how they related to the existence of self-recruiting species. The common aquatic resources identified during this phase included farmer managed aquatic systems (FMAS) and openwater bodies (OWB) where rural households usually obtained their aquatic products. The various types of FMAS which included ricefields, trap ponds, household ponds, culture ponds and ditches were identified as important aquatic resources which mainly provide food as well as additional income to the rural poor. All of these FMAS were being managed at various levels which directly affected the SRS population. Different types of farmers were identified based on their attitudes towards and management of SRS: i) SRS positive, farmers who allow and attract SRS into the system, ii) SRS negative, farmers who prevent or eliminate SRS and iii) SRS neutral, farmers doing nothing that would encourage or prevent SRS from entering into the system. Variations were related to the main factors (i.e sites, agroecological zones, wellbeing groups) and their interactions. The final stage of this study was the year-long household survey (longitudinal study) that investigated the seasonality of various aspects of rural livelihoods, status of the different aquatic systems and the important contribution of AA in general, and SRS in particular, to the overall livelihood strategies employed by rural farmers. This phase involved a total of 162 households (9 per village or 54 per country) selected based on the aquatic systems they managed and had access to. Other socio-economic factors (gender and wellbeing) were also considered during the selection of participants in this phase of the study. The results of the year long household survey highlighted the important contributions of SRS: i) to the total AA collections which were utilised in various ways, ii) contribution to overall food consumption in general and AA consumption in particular (which was found to be the most important contribution of SRS), iii) contribution to household nutrition (as a major source of animal protein and essential micro nutrients in rural areas), iv) contribution to income and expenditures, and v) improving the social capital of rural households (through sharing of production and mobilizing community in local resources user group management). Moreover, the social context and the dynamics of inter and intra household relationships were understood, especially the gender issues on division of labour (where women and children played an important part on the production), access and benefits (how women and children were being marginalised in terms of making decision and controlling benefits). The various results of the combined approaches that were utilised in all stages of the research were analysed and presented in this thesis. The results of the community appraisals and the baseline survey were used in setting the context (background) of each topic (e.g. livelihood activities, AA importance, etc). Meanwhile, the results of the longitudinal survey were used in illustrating the trends and highlighted the seasonality of particular issues. Overall the study contributed to knowledge by elucidating the status and roles of self-recruiting species in maintaining/ improving the overall livelihoods of rural farmers in Southeast Asia.

In this thesis, I have assessed and modelled invasion of alien plant species in the forest of the southeastern United States. There are over 380 recognized invasive plants in southeastern forests and grasslands with 53 ranked as high-to-medium risk to natural communities. I have focused on ten of these: Chinese lespedeza, tall fescue, Japanese honeysuckle, Chinese privet, autumn olive, princesstree, silktree, chinaberry, tree of heaven, tallowtree. Assessing them at differing scales, locally (Chapter 2 and 3), eco-regionally (Chapter 4 and 5) and regionally (Chapters 6 and 7), using field based measurements integrated with remotely sensed and digital datasets, and applying both parametric and non-parametric modelling approaches. Data from field based measurements as well as digitally available sources was evaluated, bringing together freely available data with time consuming, intensively collected data. Once models were developed application to assessing long term impacts was done by integrating potential climate change scenarios. At the local level Chinese lespedeza and Japanese Honeysuckle were the most prevalent, with models at the local level dominated by remotely sensed variables. At an eco-regional level Japanese honeysuckle was the most prevalent with models primarily dominated by environmental variables. At a regional level, where only trees were assessed, potential distributions of the invasive species ranged from 12 to 33 percent of the southeastern forests under current conditions with this dramatically increasing for chinaberry and tallowtree under most climate change scenarios, up as high as 66 percent of southeastern forest sites. In this thesis information on anthropogenic factors added some value to the models, however it was rarely dominant. Roads and land use (proportion of forest or distance to forest) were the most useful anthropogenic variables. In all models evaluated, only six times did any one anthropogenic variable represent more than 25 percent of the models, four of these were at the local scale. At the regional and eco-regional level, roads had a greater than 25 percent contribution to the silktree models, at a local level, distance to forest and distance roads contributed more than 25 percent to three of the species evaluated, sawtooth oak, Japanese honeysuckle and privet. Human activities have the most influence on invasion progression through dispersal (movement and introduction rate) and disturbance of the landscape (increased resource availability). Anthropogenic variables such as roads are likely to be a mechanism of spread, thus the more a model is driven by anthropogenic variables, the more likely the invasive plant is to be in the early stages of invasion process. Thus our results suggest that many of these species have moved through the first stages of invasion. Environmental characteristics play an important role in determining a site’s vulnerability to invasion. At an eco-region and regional scale, environmental characteristics dominated (>50%) all but one model (silktree at the regional scale). At the eco-region level elevation was the dominant variable, and at a regional level minimum temperature was the dominant variable. These have some correlation, with higher elevation often relating to lower temperatures, particularly at a smaller scale. This confirms the validity of matching the climate ranges of native species with the range of potential invasion, and the approach of integrating elevation, latitude and longitude to estimate potential distribution. It also suggests that climate change will influence the distribution and that variation in climate should be integrated into models. Two different modelling approaches, logistic regression and maximum entropy, were used throughout my thesis, and applied to the same data. Agreement between different modelling types adds strength to conclusions, while disagreement can assist in asking further questions. The inclusion in the models of similar variables with the same direction of relationships gives confidence to any inference about the importance of these variables. The geographical agreement between models adds confidence to the probability of occurrence in the area. Alternatively using the same model but different datasets can give you similar information. Overall for all models created by both logistic regression and MaxEnt, the logistic regression had slightly better omission rates and the MaxEnt model had better AUC’s. Logistic regression models also often predicted larger geographical areas of occurrences when the threshold of maximum sensitivity plus specificity was used, thus the lower omission rates is related to the less stringent model that predicts a larger area. The selection of appropriate data to answer the question was shown to be fundamental in Chapter 7. When data were used outside of the area of interest it generalized the models and increased the potential for invasion significantly. There was more value in the intensive surveyed data but this was less dramatic than in using the defined areas of interest to select the data for models.

Dendroarchaeology has a discontinuous history in the Southeastern United States, mostly because of misconceptions (the Southeast is too mesic), bad sampling practices (no standard protocol exists for preserving prehistoric wood samples), and a lack of reference tree-ring chronologies long enough to date wood from the abundant prehistoric sites. The majority of archaeological applications in recent years has focused on the dating of historic sites and structures to verify the documented year(s) of construction largely in response to requests from historical agencies to verify when a particular structure was built. We have found that most structures are one to two generations younger than their reported date(s) of construction, but most agencies find this information useful as tree-ring dating lends historical credibility to any site. The future of dendroarchaeology in the Southeast is encouraging but many more trained experts are needed to meet the demand of dating historical structures and sites. Furthermore, once a sampling protocol becomes standardized for retrieving wood from prehistoric sites, the potential for absolute dating of these sites is enormous given that abundant wood is archived in locations throughout the Southeast.