Call number: LD2668 .T4 1949 A42 / Master of Science

<p>Western Pond Turtles, <i>Emys</i> (<i>Actinemys</i>) <i> marmorata</i>, were captured (n=173) in 2011 (wet year) and 2012&ndash;2013 (successively drier drought years) along upper Coyote Creek, an intermittent stream in central California. Males outnumbered females 2.8:1, juveniles less than 120 mm long made up 26% of captures, growth rates varied among individuals, and little growth occurred in turtles older than 10 years. I radio-tracked turtles from May 2011 through August 2013 to ascertain movements and seasonal habitat use. Males had much larger home ranges than females (means of 2281 m for males and 501 m for females in 2012), and males moved extensively in April and May, during the apparent breeding season. Turtles preferred deep and complex pools, complex runs, and backwaters. Turtles left the stream for upland habitats in late spring and summer as stream flow ceased and pool connectivity was broken. There was substantial variation in departure dates among individuals and between wetter and drier reaches. Mean departure date was 16 August in 2011, but decreased to 20 July in 2012 and 28 June in 2013, as the drought intensified. Upland sites were mostly within 100 m of the stream, beneath dried leaves and/or thatch, and on slopes varying from flat to over 40%. Turtles remained upland for almost seven months in 2011&ndash;2012, although there was much variation. Mean return to stream dates were 27 February (males) and 16 March (females). </p>

<p>The efficacy of intensive rotational targeted grazing (IRTG) for suppression of the invasive shrub, multiflora rose (Rosa multiflora) was investigated in upstate New York. Sheep stocked at high density were rotated through a circuit of enclosures at a frequency of 3-d per enclosure, from May-September, 2011 and 2012. The photosynthetic surface areas (PSA) and vitality of R. multiflora plants were evaluated before (May 2011) and after treatment by grazing (Sept 2011). Changes over time were compared with similar measurements of ungrazed plants. Species richness (S) was estimated in each enclosure before (May) and after (September) treatment. PSA in grazed enclosures declined by 56.8% over the 2011 season and by 62.5% during the 2012 season. One year after ITRG treatment, healthy R. multiflora plants in grazed enclosures had declined by 91% and unhealthy and dead plants had increased by more than 200%. The distributions of healthy, unhealthy and dead plants, in grazed and ungrazed enclosures, though not different before treatment (chi square goodness of fit test; p>0.05?? were different one year later (p<0.001). Mean S in grazed enclosures increased by 27% over the season and by the end of the study, S was 12% higher than ungrazed enclosures. Evidence of stress in R. multiflora (clumping, dwarfing and reddening of leaves) at the end of the 2011 season led me to investigate the possible presence of rose rosette disease (RRD) during 2012. Potential stress was confirmed in plants experiencing leaf reddening. Chlorophyll a concentrations were significantly lower in red than green leaves (Student?s t = 5.20, df=28, p<0.001). Not unexpectedly, Normalized Difference Vegetative Index (NDVI) lso differed in red and green leaves (Student?s t = 2.76, df=32, p<0.01). Green leaves had higher dry weights than red leaves (Student?s t=14.13, df=151, p<0.001). Wool from the sheep, and R. multiflora leaf and petiole samples were collected to determine if the eriophyid mite, Phyllocoptes fructiphilus, a vector for RRD was present. No significant evidence of P. fructiphilus in leaf and petiole (Mean=0.00 N=414 SD=.71) or wool samples (Mean=0.00 N=11 SD=0) was found. This was unexpected, although it would only take one mite to be the vector if that particular mite was carrying the rose rosette virus. Further studies would be required to test whether rose rosette was confirmed in this population. Visual evidence of RRD symptoms were more prevalent in grazed enclosures than ungrazed locations, and a greater decline in grazed enclosures was clear.

The stabilisation of archaeological iron is considered as one of the major problems facing the archaeological conservator today. Free chlorides, held as counter ions at the metallic anode, act as electrolytes and promote corrosion of metallic iron This study examines and compares the efficiency of a range of aqueous wash methods currently used to remove chloride ions from archaeological iron and determines how these various treatments work. It also investigates the effect of selected aqueous wash treatments on the chloride rich metastable corrosion product 0-FeOOH. The amount of Cl'removed from 0-FeOOH and any transformations to new compounds are recorded. Iron objects were treated using aqueous Soxhlet extraction with nitrogen, aqueous sodium hydroxide and aqueous alkaline sulphite solutions. Synthetic O-FeOOH and PFeOOH1Fe3Om4 ixtures were washed in aqueouss odium hydroxide, aqueousa lkaline sulphite solution, aqueous sodium sulphite, hot and cold deionised water. The outcome of the work showed that: (1) For archaeological iron objects: O. SM nitrogen de-aerated aqueous NaOH solutions are very efficient chloride extractors, often approaching a 100% efficiency. Almost as efficient were 0.5M aqueous... NaOH/Na2SO3 treatment solutions. Nitrogen de-aeration of treatment solutions improves their cr extraction efficiency, by freeing Cl' from its counter ion role. Hydroxide ions improve extraction efficiency of Cl- from iron objects in nitrogen and Na2S03 de-aerated environments. The de-aerated aqueous Soxhlet extraction method, as suggested by Scott and Seeley (1986), is a less efficient chloride extractor than either nitrogen de-aerated 0.5M NaOH or 0.5M NaOH/Na2SO3. De-aerated NaOH treatment solutions are to be preferred to NaOH/Na2SO3 solutions, as they do not introduce residual electrolyte ions (SO 42). (2) For O-FeOOH samples: Pure O-FeOOH and P-FeOOH/Fe3O4 mixtures reacted differently during washing. Pure 0-FeOOH completely transformed to cc-FeOOH in the alkaline environments provided by NaOH and NaOH/Na2SO3. This released all the chloride from the PFeOOH. In NaOH solutions within the range pH8.5 to 10.5 0-FeOOH/Fe3O4 transformed mostly to Fe304. Above pH1 1 there was limited conversion. Improved release of Cl' from P-FeOOII/Fe3O4 mixture correlated with the transformation of PFeOOH to Fe304.

<p> Efforts to document current wild bee faunas are imperative as evidence of changes in local abundance, geographical range, and species diversity among many taxa accumulates. These changes and declines have led to an intensified effort to survey wild bees in representative habitats throughout North America. The objective of this study was to characterize the wild bee fauna of one such coastal habitat in Connecticut, USA, specifically to examine marsh, dune, and coastal scrub bee communities.</p><p> Biweekly surveys were conducted at Grass Island Preserve (Guilford, CT) over a two-year period (2011-2012) using pan traps and effort-based (timed) net collecting. A total of 3929 individual bees were collected, representing five families, 18 genera and 80 species. The total number of species collected represents approximately 23% of the known Connecticut bee fauna. Three species -<i>Hylaeus illinoisensis</i> (Robertson); <i>Hylaeus</i> aff. <i>nelumbonis</i> (undescribed); <i>Lasioglossum michiganense </i> (Mitchell) - are newly recorded for Connecticut. Species accumulation curves constructed for all sub-habitats indicated that bee diversity was steadily increasing over the sample period. No asymptote in accumulation curves were observed at any site.</p>

No description available.

<p> This thesis examined avian population dynamics over a four year span (2011-2014) in four forest types in Kings Canyon, Sequoia, and Yosemite National Parks, California. I asked, do bird populations show fluctuations in abundance and species richness depending on early spring snowpack levels in various forest types of the Sierra Nevada? I conducted point transect sampling surveys as part of the Sierra Nevada Network's Inventory and Monitoring bird monitoring program. To calculate local abundances for fourteen common bird species, I modeled detection functions in program Distance 6.2. I also determined species richness for each transect, and finally correlated avian abundance with spring snow depths. None of the common bird species in this study displayed a strong correlation between their abundance and snow depths in any of the four years. Clark&rsquo;s Nutcracker indicated potential for a positive correlation for abundance and snow depth, but this result may have been driven by other factors. With changing climate in the Sierra Nevada expected to increase the variability of snowpack among years, it is crucial to continue studying relationships between bird populations and snowfall in the Sierra Nevada.</p>

Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Widespread, human-induced ecosystem degradation and the associated biodiversity loss pose a direct threat to human wellbeing. While there is no substitute for healthy, self-sustaining ecosystems, ecological restoration offers an attractive, and indeed inevitable, supplement where conservation alone is not sufficient to support ecosystem integrity. Restoration is undergoing a revolution, where evidence-based (EB) practice is emerging as a new approach to increase the chances of successfully achieving restoration goals. EB practice is based on the notion that implementation decisions need to be based on the appraisal and use of evidence of effectiveness of alternative options. The point of departure of this thesis is the contention that EB practice need not be dependent only on research evidence. The work presented herein thus addresses the production and use of evidence of effectiveness in restoration practice. Using ten restoration programs in South Africa, the quality of evidence produced in practice was assessed. Three components of evidence production that were evaluated were (i) baseline condition measurement; (ii) goal setting and (iii) monitoring. Results showed poor definition of goals; a bias towards the use of socio-economic goals and indicators; more monitoring of inputs than impact; and inconsistent and short-term monitoring of biophysical indicators. Practitioners regarded the evidence base as adequate, but cited a few challenges associated with planning and resource availability as attributing factors to the gaps observed. I propose that practitioners’ perception of the current evidence base poses an additional threat to the generation of a strong evidence base. In addition to the production of evidence, access to said evidence is a vital component of EB practice. In an exploration of how evidence is made available by practitioners, it became evident in that a considerable amount of the information that was not easily accessible in documented form was known by the practitioners. This highlights the need for a shift in practice culture towards the valuing and rewarding of the dissemination of information. An assessment of EB restoration would have been incomplete without a deliberate consideration of social factors. I thus conducted a case study of an invasive alien plant clearing program, to determine what drives the use of scientific evidence in decision making. I observed that organizational structure, policies, priorities and capacity influence, and even limit, the use of scientific evidence to inform decisions. The challenges to making restoration evidence-based are diverse in nature, ranging from poor planning of restoration work, which points to limited appreciation of the need to produce a strong evidence base, to a lack of instruments and incentives to drive the generation, dissemination and use of evidence that spans both the biophysical and social aspects of restoration. These challenges are largely rooted in the conventional way of approaching restoration from individual disciplinary perspectives, thus artificially simplifying and compartmentalizing a naturally complex problem like degradation. I end by proposing transdisciplinarity, which focuses on a holistic world view and the production of knowledge that embraces complexity, as a possible vehicle to help move the practice of restoration towards being evidence-based. / AFRIKAANSE OPSOMMING: Wydverspreide, mens-veroorsaakte agteruitgang van ekostelsels en die gepaardgaande verlies aan biodiversiteit hou 'n direkte bedreiging vir menslike welsyn in. Alhoewel daar geen plaasvervanger is vir 'n gesonde, selfonderhoudende ekostelsel is nie, bied ekologiese restourasie 'n aantreklike en inderdaad onvermydelik, vul waar bewaring alleen nie voldoende ekosisteem integriteit kan ondersteun nie. Restourasie ondergaan tans ‘n revolusie, waar bewys gebaseerde (BG) praktyk 'n opkomende nuwe benadering om die kanse van die suksesvolle bereiking van herstel doelwitte te verhoog. BG praktyk is gebaseer op die idee dat die uitvoering van besluite gebaseer moet word op die evaluering en die gebruik van bewyse van die effektiwiteit van alternatiewe opsies. Die punt van vertrek van hierdie proefskrif is die bewering dat BG praktyk nie noodwendig afhanklik van navorsings bewys hoef te wees nie. Die werk wat hier aangebied word spreek tot die produksie en gebruik van bewyse van effektiwiteit in die restourasie praktyk. Deur die gebruik van tien restourasie programme in Suid-Afrika is die kwaliteit van die bewyse in die praktyk geassesseer. Die drie komponente van bewyse produksie wat geëvalueer is sluit in (i) basislyn toestand meting, (ii) doelwitstelling en (iii) monitering. Resultate toon 'n swak definisie van doelwitte; 'n vooroordeel ten gunste van die gebruik van sosio-ekonomiese doelwitte en aanwysers; meer monitering van insette as die impak; en teenstrydige en kort-termyn monitering van biofisiese aanwysers. Beofenaars het die gebruik van bewys gebaseerde inligting as voldoende beskou, maar 'n paar uitdagings wat verband hou met die beplanning en die beskikbaarheid van bronne is aangehaal as kenmerkende faktore in die gapings wat tans waargeneem word. Ek stel voor dat beoefenaars se persepsie van die huidige bewysbasis praktyk 'n bykomende bedreiging vir die generasie van 'n sterk bewybasis praktyk inhou. Benewens die produksie van bewyse, is die toegang tot bewyse 'n belangrike komponent van die BG praktyk. In die verkenning van hoe bewyse beskikbaar gestel word deur beoefenaars, is dit duidelik dat 'n aansienlike aantal inligting wel bekend is aan beofenaars maar nie maklik toeganklik in gedokumenteerde vorm is nie. Dit beklemtoon die behoefte vir 'n verskuiwing in die praktyk kultuur tot die waardering en beloning van die verspreiding van inligting. 'n Beoordeling van die BG herstel sou onvolledig wees sonder 'n doelbewuste oorweging van sosiale faktore. Ek het dus 'n gevallestudie van 'n indringerplant verwyderings program uitgevoer om vas te stel wat die gebruik van wetenskaplike bewyse in besluitneming aandryf. Ek het opgemerk dat die organisatoriese struktuur, beleid, prioriteite en kapasiteit die gebruik van wetenskaplike bewyse kan beinvloed, en selfs beperk. Die uitdagings om herstelwerk bewys-gebaseerd te maak is uiteenlopend van aard, dit wissel van swak beplanning van herstel werk, wat dui op beperkte waardering van die behoefte om 'n sterk bewyse basis te produseer, 'n gebrek aan instrumente en aansporings vir die generasie van besyse, verspreiding en gebruik van bewyse wat strek oor beide die biofisiese en maatskaplike aspekte van die restaurasie. Hierdie uitdagings is grootliks gegrond op die konvensionele manier van restaurasie wat gebaseer is op individuele dissiplinêre perspektiewe,wat lei tot die kunsmatige simplifiseering van ‘n uiteraand komplekse problem soos agteruitgang. Ek eindig af deur die gebruik van transdissiplinariteit, wat fokus op 'n holistiese wêreldbeskouing en die produksie en kennis van kompleksiteit insluit voor te stel, as 'n moontlike voertuig om die skuif in praktyk van restourasie na n bewys-basis te vergemaklik.

<p> The main goals of this study were to map the current distribution of the invasive eastern gray squirrel in California as of 2016, to project the potential future geographic range of the species, and to identify areas where the future range of the eastern gray squirrel is likely to overlap the range of the native western gray squirrel. Location data were obtained from museum specimens, wildlife rehabilitation centers, a roadkill database, and research-grade citizen observations. Ecological niche models were created with Maxent, while range and habitat suitability maps were produced with ArcGIS software. Populations of eastern gray squirrels are currently concentrated around Sacramento, the San Francisco Bay, Monterey, and Bellota. The highest priority areas for control and eradication are areas of western gray squirrel habitat near existing eastern gray squirrel populations, including both peninsulas of the San Francisco Bay, areas near Santa Cruz, Oakland, Santa Rosa, and the Monterey Peninsula.</p>

Thesis (MSc (Conservation Ecology and Entomology)--Stellenbosch University, 2007. / A systematic conservation assessment is the first phase of a systematic conservation planning protocol; it uses spatial data and representation targets for the setting of priority areas and the assessment of risk to biodiversity. This thesis describes the findings of investigations on the use of data in systematic conservation assessments. Conservation planning can be done at different spatial scales (from global to local). Systematic Conservation planning can be done at different spatial scales (from global to local). Systematic conservation assessments rely on the use of surrogates for biodiversity and often, as well, socioeconomic criteria. Biodiversity surrogates can be classified as taxonomic, community and environmental. In Chapter 2, a literature review was performed (i) to quantify the use of biodiversity surrogates and socio-economic criteria in conservation assessments; and (ii) to test the hypothesis that surrogates are chosen in respect to the hierarchical organisation of biodiversity. In other words, fine scale conservation assessments are correlated with taxonomic surrogates, large scale conservation assessments are correlated with environmental surrogates, and assemblage surrogates are assessed at an intermediary scale. The literature review was based on a structured survey of 100 ISI journal publications. The analysis revealed that spatial scale had a weak effect on the use of biodiversity surrogates in conservation assessments. Taxonomic surrogates were the most used biodiversity surrogates at all scales. Socioeconomic criteria were used in many conservation assessments. I argue that it is crucial that assemblage and environmental data be more used at larger spatial scales. The allocation of conservation resources needs to be optimised because resources are scarce. A conservation assessment can be a lengthy and expensive process, especially when conducted at finescale. Therefore the need to undertake a fine-scale conservation assessment, as opposed to a more rapid and less expensive broader one, should be carefully considered. The study of Chapter 3 assessed the complementarity between regional- and local-scale assessments and the implications on the choice of biodiversity features at both scales. The study was undertaken in Réunion Island. A biodiversity assessment was performed at a regional scale and measured against a finer-scale assessment performed over a smaller planning domain. Two datasets composed of species distributions, habitat patterns and spatial components of ecological and evolutionary processes were compiled as biodiversity surrogates at each scale. Targets for local-scale processes were never met in regional assessments, while threatened species and fragmented habitats were also usually missed. The regional assessment targeting habitats represented a high proportion of local-scale species and habitats at target level (67%). On the contrary, the one targeting species was the least effective. The results highlighted that all three types of surrogates are necessary. They further suggested (i) that a spatial strategy based on a complementary set of coarse filters for regional-scale assessments and fine filters for local-scale ones can be an effective approach to systematic conservation assessments; and (ii) that information on habitat transformation should help identify where efforts should be focused for the fine-scale mapping of fine filters. Together with priority-area setting, the identification of threatened biodiversity features has helped to prioritise conservation resources. In recent years, this type of assessment has been applied more widely at ecosystem-level. Ecosystems can be categorised into critically endangered, endangered and vulnerable, following the terminology of the IUCN Red List of threatened species. Various criteria such as extent and rate of habitat loss, species diversity and habitat fragmentation can be used to identify threatened ecosystems. An approach based only on the criterion of the quantification of habitat loss was investigated in Chapter 4 for the Little Karoo, South Africa. Habitat loss within ecosystem type is quantified on land cover information. The study analysed the sensitivity of the categorisation process to ecosystem and land cover mapping, using different datasets of each. Three ecosystem classifications and three land cover maps, of different spatial resolutions, were used to produce nine assessments. The results of these assessments were inconsistent. The quantification of habitat loss varied across land cover databases due to differences in their mapping accuracy. It was reflected on the identification of threatened ecosystems of all three ecosystem classifications. Less than 14% of extant areas were classified threatened with the coarsest land cover maps, in comparison to 30% with the finest one; and less than 9% of ecosystem types were threatened with the coarsest land cover maps, but between 15 and 23% were threatened with the finest one. Furthermore, the results suggested that the identification of threatened ecosystems is more sensitive to the accuracy of habitat loss quantification than the resolution of the ecosystem classification. Detailed land cover mapping should be prioritised over detailed ecosystem maps for this exercise. This thesis highlighted the importance of ecosystems and processes as biodiversity surrogates in conservation assessments and suggested that results of conservation assessments based on these data, should be more widely presented in published articles. Finally, it also made apparent the important role of mapping habitat transformation for systematic conservation plans.