Source: Masters Abstracts International, Volume: 47-06, page: 3475. Advisers: Elaine Symanski; Thomas H. Stock. Includes bibliographical references

Thesis (Ph.D.) -- McMaster University, 1997. / Includes bibliographical references. Also available via World Wide Web.

Thesis (D.P.H.)--University of Michigan, 1996.

Thesis (D.P.H.)--University of Michigan, 1996.

Thesis (M. Sc.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 42-47).

Thesis (Ph.D.)--University of Delaware, 2005 . / Principal faculty advisor: Biliana Cicin-Sain, College of Marine Studies. Includes bibliographical references.

<p>Modern advances in biometeorological monitoring technology have improved the capacity for measuring ecosystem exchanges of mass, energy and scalars (such as CO₂). Translating these measurements into robust and accurate scientific information (and ultimately, understanding) requires careful assessment of operations throughout the biometeorological data life cycle. In response, this research analyzed and optimized aspects of data collection, management and filtering for an ecosystem exchange measurement program over an age-sequence of temperate white pine forests.</p> <p>A comprehensive data workflow and management system (DWMS) was developed and implemented to support the entire data life cycle for all past, present and future measurement operations in our research group, and meet the needs of a collaborative, student-led data management environment. Best practices for biometeorological data management were introduced and used as standards to assess system performance.</p> <p>Roving eddy covariance (rEC) systems were examined as a means of producing reliable time-integrated carbon exchange estimates at multiple sites, by rotating an EC system in a resource-mindful approach. When used with an optimal gap-filling model and rEC rotation schedule (2 sites with 15-day rotations), the results suggested its viability, as annual NEE estimate uncertainties ranged between 35 and 63% of the annual NEE flux magnitude at our study sites – even though approximately 70% of half-hours were filled.</p> <p>Lastly, a data-driven approach was used to investigate the effects of different friction velocity and footprint filtering methods on time-integrated carbon exchange estimates at our fetch-limited forests. Though predicted flux source areas varied considerably between footprint models, our objective analyses identified the model (Kljun et al., 2004) and within-fetch requirement (80%) that optimized reliability and representativeness of carbon exchange estimates. Applying this footprint model decreased annual NEE by 31 to 129% (59 to 207 g C m^-2 y^-1) relative to no footprint application, and highlighted the importance of objective analyses of EC flux filtering methods.</p> / Doctor of Philosophy (PhD)

Environmental monitoring represents a major application domain for wireless sensor networks (WSN). However, despite significant advances in recent years, there are still many challenging issues to be addressed to exploit the full potential of the emerging WSN technology. In this dissertation, we introduce the design and implementation of low-power wireless sensor networks for long-term, autonomous, and near-real-time environmental monitoring applications. We have developed an out-of-box solution consisting of a suite of software, protocols and algorithms to provide reliable data collection with extremely low power consumption. Two wireless sensor networks based on the proposed solution have been deployed in remote field stations to monitor soil moisture along with other environmental parameters. As parts of the ever-growing environmental monitoring cyberinfrastructure, these networks have been integrated into the Texas Environmental Observatory system for long-term operation. Environmental measurement and network performance results are presented to demonstrate the capability, reliability and energy-efficiency of the network.

Visual surveys provide for non-invasive sampling of organisms and habitats in the marine environment. They are particularly important in deep-sea habitats which are vulnerable to damage caused by alternative destructive sampling devices such as bottom trawls. However, traditional visual survey platforms tend to have limited area coverage which is insufficient for mapping the vast expanses of the deep-sea, particularly for relatively sparsely distributed organisms such as fish. This thesis presents the development of a visual survey method capable of surveying large areas of the seabed in deep waters (> 200 m) using a towed video camera system. The area of seabed sampled was similar to that sampled by a bottom trawl, making the system effective for surveying fish. Anglerfish densities were found to be comparable to those determined by trawl surveys in adjacent areas. For other deep-sea fish, the two survey methods (towed camera and bottom trawl) provided different results which were explained by the behavioural reactions of different fish taxa to the respective gears. Fish that exhibited detectable avoidance behaviour to the towed video camera system (e.g. Chimaeridae) resulted in significantly lower density estimates than trawl estimates. On the other hand, skates and rays showed no reaction to the towed video camera system, and density estimates of these were an order of magnitude higher than the trawl. The towed video camera survey was also deployed to gather data on the cold-water coral Lophelia pertusa on the Rockall Bank. These data were used together with Species Distribution Modelling (SDM) to predict the distribution of Lophelia pertusa habitat. The current closed areas on the Rockall Bank cover sizeable areas of potential Lophelia pertusa habitat, however, based on the predictions further areas could be considered to ensure the continued protection of this species.

Thesis (PhD)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Dragonflies (Insecta: Odonata) are a valuable tool for assessing aquatic systems and have been used as indicators of ecological health, ecological integrity, and environmental change, including climatic change. In four separate studies I explored the usefulness of dragonflies as surrogates in biomonitoring, site prioritization and indication of global climate change. In the use of dragonflies for biomonitoring, I field-tested a freshwater ecological integrity index, the Dragonfly Biotic Index (DBI), based on dragonfly assemblages at the local scale, and compared the DBI to a standard freshwater benthic macroinvertebrate-based freshwater health index. Overall, dragonflies were more sensitive to changes in river condition than were macroinvertebrates, and the DBI site value and macroinvertebrate scores were highly significantly correlated. I conclude that dragonfly assemblages in the form of a DBI are an excellent tool for environmental assessment and monitoring freshwater biodiversity, with the potential to replace benthic macroinvertebrate-based freshwater quality assessments. In the second study, I used the DBI to prioritize sites for conservation action in South Africa. Using a selected set of top prioritized sites, I compared the DBI’s performance to that of a rarity-complementarity algorithm. Site prioritization using the DBI reveals that CFR sites protect Red Listed taxa rather well. The rarity-complementarity algorithm represents all species, but without greater emphasis on the rare and threatened species. I conclude that the DBI is of great value in selecting biodiversity hotspots, while the algorithm is useful for selecting complementarity hotspots. The third study was made possible by the recent completion of a continental assessment of freshwater biodiversity, which revealed that patterns of richness and threat of four well-studied aquatic taxa largely coincide at the continental scale. Using only dragonflies, I built a protected areas network for Africa using spatial planning software. I then compared the performance of the existing African reserve network and that of known global biodiversity hotspots against the model, and identified sites of conservation concern. Although the current reserve network covers 10.7% of the landscape, the proportional representation of species geographic distributions in reserves is only 1.1%. The reserve network is therefore inefficient, and many areas of conservation priority that are not formally protected remain. The advantage of operating at the fine scale, while covering a large geographic area is that it shifts the focus from the large-scale hotspots to smaller priority areas within and beyond hotspots. In the fourth study, I created species distribution models of dragonflies in an El Niño-prone biodiversity hotspot in South Africa, and predicted the changes in species richness, geographic range and habitat suitability, forty and eighty years from now. According to the model results of two different emissions scenarios, at least three species will be lost from the area by 2050, and four by 2080. The remaining species are predicted to persist with reduced geographical ranges, at generally higher elevations. Most species presented here thrive quite well in artificial environments, that is, engineered ponds or dams. It is therefore unlikely that loss in connectivity will play a role for these species. / AFRIKAANSE OPSOMMING: Naaldekokers (Insecta:Odonata) is waardevolle instrumente om akwatiese sisteme te assesseer, en is al gebruik as aanwysers van ekologiese gesondheid, ekologiese integriteit en omgewingsverandering, insluitend klimaatsverandering. In vier studies het ek die nut van naaldekokers as surrogate in biomonitering, area prioritisering en indikasie van globale klimaatsverandering ondersoek. In die benutting van naaldekokers in biomonitering, het ek ´n varswater ekologiese integriteits indeks, die Dragonfly Biotic Index (DBI), wat gebaseer is op naaldekokergemeenskappe op die plaaslike skaal, getoets en dit vergelyk met ´n standaard bentiese makroinvertebraat-gebaseerde varswater gesondheids index. Naaldekokers was meer sensitief vir veranderinge in riviertoestand as makroinvertebrate, en die DBI lokaliteit waarde en makroinvertebraat telling was beduidend gekorreleer. Die gevolgtrekking was dat naaldekoker gemeenskappe in die vorm van die DBI ‘n uitstekende instrument is vir omgewings assessering en die monitering van varswater biodiversiteit, met die potensiaal om bentiese makroinvertebraat-gebaseerde varswaterkwaliteit assessering te vervang. In die tweede studie, het ek die DBI gebruik om areas te prioritiseer vir bewaringsaksie in Suid Afrika. Met die gebruik van ‘n geselekteerde set top prioriteit areas, het ek die DBI se prestasie vergelyk met die van ‘n rariteit-komplemetariteit algoritme. Area prioritisering met die gebruik van die DBI het aangedui dat CFR areas taxa op die Rooi Lys goed beskerm. Die rariteit-komplementariteit algoritme verteenwoordig alle spesies, maar beklemtoon minder skaars en bedreigde spesies. Die gevolgtrekking was dat die DBI van meer waarde is in die selektering van biodiversiteits ‘hotspots‘, terwyl die algoritme nuttig is vir die selektering van komplementariteits ‘hotspots‘. Die derde studie was moontlik gemaak deur die onlangse voltooiing van ‘n kontinentale assessering van varswater biodiversiteit, wat aangedui het dat patrone van rykheid en bedreiging van vier goed-bestudeerde akwatiese taxa grootliks ooreenstem op die kontinentale skaal. Met die gebruik van naaldekokers, het ek ‘n beskermde area netwerk gebou vir Afrika met ruimtelike beplannings sagteware. Ek het die prestasie van die bestaande Afrika reservaatnetwerk en die van bekende globale biodiversiteit ‘hotspots‘ vergelyk teen die model, en het areas van bewaringsbelang geidentifiseer. Alhoewel die bestaande reservaatnetwerk 10.7% van die landskap dek, is die proporsionele verteenwoordiging van spesies se geografiese verspreiding net 1.1%. Die reservaatnetwerk is dus onvoldoende en baie areas van bewaringsbelang is nie formeel beskerm nie. Die voordeel van op die fyn skaal werk terwyl ‘n groot geografiese are gedek word, is dat dit die fokus van groot skaal ‘hotspots‘ na kleiner prioriteits areas binne en buite ‘hotspots‘ verskuif. In die vierde studie, het ek spesies verspreidingsmodelle van naaldekokers geskep in ‘n El Nino-geneigde biodiversiteits ‘hotspot’ in Suid Afrika, en het veranderinge in spesies rykheid, geografiese verspreiding en habitatsgeskiktheid voorspel, veertig en tagtig jaar van nou af. Volgens die modelresultate van twee verskillende emissie scenarios, sal ten minste drie spesies verlore gaan uit die area teen 2050, en vier teen 2080. Daar word voorspel dat die oorblywende spesies sal voortduur in verkleinde geografiese areas, by groter hoogte bo seespieël. Die meeste spesies hier verteenwoordig floreer in kunsmatige omgewings, soos mensgemaakte damme. Dit is dus onwaarskynlik dat ‘n verlies in konnektiwiteit ‘n rol sal speel vir hierdie spesies.