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Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 5 uppsatser.

Thesis (MSc (Botany and Zoology))--University of Stellenbosch, 2005. / South Africa is one of the most biodiverse countries in the world and even with conservation initiatives in place continues to face biodiversity loss. There is a need to prioritise areas for conservation as resources for conservation purposes are limited in South Africa. From prioritisation methods reviewed it was found that prioritisation indices normally use one or a combination of variables that measure stock; and/or variables that measure threat.

It is becoming increasingly important to monitor biodiversity in the extensive Australian rangelands; currently however, there is no method capable of achieving this goal. There are two potential sources of relevant data that cover the Australian rangelands, and from which measures of biodiversity might be extracted: traditional field-based methods such as quadrat surveys have collected flora and fauna species data throughout the rangelands, but at fine scale; satellite remote sensing collects biologically relevant, spatially comprehensive data. The goal of this thesis was to provide the spatially comprehensive measure of biodiversity required for informed management of the Australian rangelands. The study specifically focused on the Stony Plains in the South Australian rangelands. To that end the thesis aimed to develop indices capable of measuring and/or monitoring biodiversity from vegetation quadrat survey data and remotely sensed data. The term biodiversity is so all-encompassing that direct measurement is not possible; therefore it is necessary to measure surrogates instead. Total perennial vegetation species richness (y-diversity) is a sound surrogate of biodiversity: the category of species is well defined, species richness is measurable, and there is evidence that vegetation species richness co-varies with the species richness of other taxonomic groups in relation to the same environmental variables. At least two broad scale conventional vegetation surveys are conducted in the study region; the Biological Survey of South Australia; and the South Australian Pastoral Lease Assessment. Prior to the extraction of biodiversity data the quality of the BSSA, the best biodiversity survey, was evaluated. Analysis revealed that false-negative errors were common, and that even highly detectable vegetation species had detection probabilities significantly less than one. Without some form of correction for detectability, the species diversity recorded by either vegetation survey must be treated with caution. Informed by the identification of false-negative errors, a method was developed to extract y-diversity of woody perennials from the survey data, and to remove the influence of sampling effort. Data were aggregated by biogeographic region, rarefaction was used to remove most of the influence of sampling effort, and additional correction removed the residual influence of sampling effort. Finally, additive partitioning of species diversity allowed extraction of indices of a-, β- and y-diversity free from the influence of sampling effort. However, this woody perennial vegetation y-diversity did not address the need for a spatially extensive, fine scale measure of biodiversity at the extent of the study region. The aggregation of point data to large regions, a necessary part of this index, produces spatially coarse results. To formulate and test remotely sensed surrogates of biodiversity, it is necessary to understand the determinants of and pressures on biodiversity in the Australian rangelands. The most compelling explanation for the distribution of biodiversity at the extensive scales of the Australian rangelands is the Productivity Theory, which reasons that the greater the amount and duration of primary productivity the greater the capacity to generate and support high biodiversity. The most significant pressure on biodiversity in the study area is grazing-induced degradation, or overgrazing. Two potential spatially comprehensive surrogates of pressure on biodiversity were identified. The first surrogate was based on the differential effect of overgrazing on waterenergy balance and net primary productivity: water-energy balance is a function of climatic variables, and therefore a measure of potential or expected primary productivity; net primary productivity is reduced by high grazing pressure. The second surrogate was based on the effect of grazing-induced degradation on the temporal variability of net primary productivity: overgrazing reduces mean net primary productivity and rainfall use efficiency, and increases variation in net primary productivity and rainfall use efficiency. The two surrogates of biodiversity stress were derived from the best available remotely sensed and climate data for the study area: actual evapotranspiration recorded by climate stations was considered an index of water-energy balance; net primary productivity was measured from NOAA AVHRR integrated NDVI; rainfall use efficiency (biomass per unit rainfall) was calculated from rainfall data collected at climate stations and the net primary productivity measure. Finally, the surrogates were evaluated against the index of woody perennial a-, β- and y-diversity, on the assumption that prolonged biodiversity stress would reduce vegetation species diversity. No link was found between Surrogate 1 and woody perennial a-, β- or y-diversity. The relationship of Surrogate 2 to woody perennial diversity was more complex. Only some of the results supported the hypothesis that overgrazing decreases y-diversity and average NPP and RUE. Importantly, none of the results supported the most important part of the hypothesis that the proposed indices of biodiversity pressure would co-vary with woody perennial a-diversity. Thus, the analysis did not reveal a convincing link between either surrogate and vegetation species diversity. However, the analysis was hampered to a large degree by the climate data, which is interpolated from a very sparse network of climate stations. This thesis has contributed significantly to the measurement and monitoring of biodiversity in the Australian rangelands. The identification of false-negative errors as a cause for concern will allow future analyses of the vegetation survey data to adopt methods to counteract these errors, and hence extract more robust information. The method for extracting sampling effort corrected indices of a-, β- and y-diversity allow for the examination and comparison of species diversity across regions, regardless of differences in sampling effort. These indices are not limited to rangelands, and can be extracted from any vegetation quadrat survey data obtained within a prescribed methodology. Therefore, these tools contribute to global biodiversity measurement and monitoring. Finally, the remotely sensed surrogates of biodiversity are theoretically sound and applicable in any rangeland where over-grazing is a significant source of degradation. However, because the evaluation of these surrogates in this thesis was hampered by available data, further testing is necessary. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1346544 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2008

Une grande diversité d’animaux produit des sons pour communiquer, s'orienter, ou lors de la réalisation d'actes comportementaux comme la prise de nourriture. Ces sons ne se répartissent pas aléatoirement dans l'espace et le temps suggérant l'existence de règles d'assemblage sonore qui structurent les populations et communautés acoustiques. Les environnements d'eau douce, et en particulier les mares, sont considérés comme les réservoirs d'une importante diversité biologique, et donc potentiellement abritant un nombre significatif d'espèces produisant des sons. Cependant la diversité acoustique de ces milieux naturels n'a jamais été explorée.L'objectif principal de cette thèse est d'explorer pour la première fois la diversité acoustique présente dans les milieux d'eau douce en climat tempéré en étudiant les structures des populations et communautés acoustiques et en explorant les processus pouvant déterminer ces structures.Une revue bibliographique sur la production sonore par les organismes d'eau douce ainsi que des enregistrements d'espèces cibles effectués en laboratoire révèlent qu'une diversité acoustique particulière existe dans les environnements d'eau douce en milieux tempérés. Pour comprendre comment cette diversité est structurée, les communautés acoustiques de trois mares situées dans des environnements différents ont été enregistrées et suivies au cours du temps. Cette étude révèle que les trois mares sont caractérisées par des communautés acoustiques riches et distinctes ayant des dynamiques spatio-temporelles spécifiques. Les facteurs potentiels structurant les communautés acoustiques d’eau douce ont été recherchés en testant si la composition de communautés acoustiques dans six bras morts de la plaine d'inondation du Rhône était liée à des variables environnementales. Nos résultats montrent que les communautés acoustiques des bras morts sont significativement liées à une variable environnementale : le degré de connectivité entre les bras morts et le lit principal de la rivière. Ce résultat suggère un rôle clé de cette variable dans les règles d'assemblage des communautés. Enfin, pour comprendre les processus possibles liant la production de sons et l'environnement naturel, une population de l'insecte aquatique Micronecta scholtzi a été suivie par des enregistrements acoustiques dans une mare méditerranéenne. Le niveau d'activité acoustique de M. scholtzi a été estimé de façon continue à l'aide d'un réseau de 12 capteurs sonores synchronisés. L'activité acoustique était caractérisée par un rythme circadien, dont les propriétés étaient perturbées par la diffusion expérimentale d'un bruit d'origine anthropique. Cette expérience révèle que les effets de la pollution sonore peuvent être observés à l'échelle d'une population d'insectes aquatiques.Ce travail montre ainsi l'existence d'une diversité acoustique dans les milieux d'eau douce et identifie des relations entre production acoustique et facteurs environnementaux. Ce travail ouvre également des perspectives intéressantes d'utilisation de l'acoustique pour aborder des problématiques d'écologie fondamentale et appliquée en milieu d'eau douce. / An important diversity of animal species produces sounds during communication, orientation, movement, or prey-predator acts. These sounds are not distributed randomly in space and time and are therefore thought to follow assembly rules forming either acoustic populations or acoustic communities. Freshwater environments and ponds in particular, are considered as primary resources for biological diversity and as such host a potentially significant number of soniferous species. However the acoustic diversity of these natural environments remains totally unexplored.The main aim of this PhD was to explore for the first time the acoustic diversity found in temperate freshwater by studying the patterns and structural processes of a selection of acoustic populations and communities recorded in several types of freshwater environments. A review of the literature on sound production by freshwater organisms along with laboratory recordings of target species revealed that a valuable acoustic diversity can be found in temperate freshwater environments. To understand how the acoustic diversity is structured, the acoustic communities of three temperate ponds were acoustically monitored. This study revealed that the three ponds were characterized by rich and distinct acoustic communities with specific spatio-temporal dynamics. To further understand the potential factors structuring freshwater acoustic communities, environmental variables were assessed along with the composition of acoustic communities found in six secondary channels of the Rhône riverine floodplain. Two environmental variables were investigated: the water temperature and the level of lateral connectivity of the secondary channels to the main river. Acoustic communities in the Rhône riverine floodplain were clearly structured by lateral connectivity suggesting a role of this key variable as an assembly rule. Finally to understand the possible processes linking animal acoustics and the natural environment, a population of aquatic insect, Micronecta scholtzi, was acoustically monitored in a Mediterranean pond. The level of M. scholtzi acoustic activity was assessed continuously using a network of twelve synchronised acoustic sensors. The acoustic activity of \textit{M. scholtzi} showed a regular daily pattern that was modified in amplitude and phase by the playback of an anthropogenic noise. This experiment revealed that the effects of noise pollution may emerge at an aquatic insect population level. This PhD unraveled the existence of a significant amount of unexplored acoustic diversity in freshwater environments and identified links between acoustics and the environment. This research opens interesting perspectives in the use of acoustic to tackle fundamental and applied ecological questions in freshwater environments.

An increasing amount of both physical and mental layers keep distancing urban dwellers from the biophysical envi- ronment that we often call nature. Environmental psycholo- gists have coined the term ‘extinction of experience’ to de- scribe the decreasing amount of encounters urban dwellers have with the natural environment. With the depletion of these experiences we have less relation to the natural world. And what we cannot relate to, we find hard to value. The intent has been to explore new ways urban dwelling adults could interact with the natural environment in order to help them relate to the abstract notion of biodiversity. The final concept is inspired by expert and user insights gathered through ethnographic research methods. The resulting design concept is a service and product eco- system that is based in the field of soundscape ecology.

<p>  </p> <p>The rise of technology as a data source for ecological research and biodiversity conservation has led to a host of new opportunities, and new challenges, for researchers, conservationists, policymakers, and land managers. As these technologies have become more common and more capable, researchers need improved methods and improved theoretical frameworks to integrate these technologies with each other; with social science and policy; and with land-use planning. This thesis proposes several of these conceptual and theoretical frameworks—one for integration of heterogeneous data and another for the integration of ecological data with economic decision-making and policy analysis. It then suggests new methodologies for data quality assurance. Lastly, it demonstrates the applicability of acoustic monitoring in a key land-use context: agriculture in a premium crop that is grown in global biodiversity hotspots. </p>

Dramatische ökologische, ökonomische und soziale Veränderungen bedrohen die Stabilität von Ökosystemen weltweit und stellen zusammen mit neuen Ansprüchen an die vielfältigen Ökosystemdienstleistungen von Wäldern neue Herausforderungen für das forstliche Management und Monitoring dar. Neue Risiken und Gefahren, wie zum Beispiel eingebürgerte invasive Arten (Neobiota), werfen grundsätzliche Fragen hinsichtlich etablierter forstlicher Managementstrategien auf, da diese Strategien auf der Annahme stabiler Ökosysteme basieren. Anpassungsfähige Management- und Monitoringstrategien sind deshalb notwendig, um diese neuen Bedrohungen und Veränderungen frühzeitig zu erkennen. Dies erfordert jedoch ein großflächiges und umfassendes Monitoring, was unter Maßgabe begrenzter Ressourcen nur bedingt möglich ist. Angesichts dieser Herausforderungen haben Forstpraktiker und Wissenschaftler begonnen auch auf die Unterstützung von Freiwilligen in Form sogenannter „Citizen Science“-Projekte (Bürgerwissenschaft) zurückzugreifen, um zusätzliche Informationen zu sammeln und flexibel auf spezifische Fragestellungen reagieren zu können. Mit der allgemeinen Verfügbarkeit des Internets und mobiler Geräte ist in Form sogenannter sozialer Medien zudem eine neue digitale Informationsquelle entstanden. Mittels dieser Technologien übernehmen Nutzer prinzipiell die Funktion von Umweltsensoren und erzeugen indirekt ein ungeheures Volumen allgemein zugänglicher Umgebungs- und Umweltinformationen. Die automatische Analyse von sozialen Medien wie Facebook, Twitter, Wikis oder Blogs, leistet inzwischen wichtige Beiträge zu Bereichen wie dem Monitoring von Infektionskrankheiten, Katastrophenschutz oder der Erkennung von Erdbeben. Anwendungen mit einem ökologischen Bezug existieren jedoch nur vereinzelt, und eine methodische Bearbeitung dieses Anwendungsbereichs fand bisher nicht statt. Unter Anwendung des Mikroblogging-Dienstes Twitter und des Beispiels eingebürgerter invasiver Arten in Waldökosystemen, verfolgt die vorliegende Arbeit eine solche methodische Bearbeitung und Bewertung sozialer Medien im Monitoring von Wäldern. Die automatische Analyse sozialer Medien wird dabei als opportunistisches „Citizen Science“-Modell betrachtet und die verfügbaren Daten, Aktivitäten und Teilnehmer einer vergleichenden Analyse mit existierenden bewusst geplanten „Citizen Science“-Projekten im Umweltmonitoring unterzogen. Die vorliegenden Ergebnisse zeigen, dass Twitter eine wertvolle Informationsquelle über invasive Arten darstellt und dass soziale Medien im Allgemeinen traditionelle Umweltinformationen ergänzen könnten. Twitter ist eine reichhaltige Quelle von primären Biodiversitätsbeobachtungen, einschließlich solcher zu eingebürgerten invasiven Arten. Zusätzlich kann gezeigt werden, dass die analysierten Twitterinhalte für die untersuchten Arten markante Themen- und Informationsprofile aufweisen, die wichtige Beiträge im Management invasiver Arten leisten können. Allgemein zeigt die Studie, dass einerseits das Potential von „Citizen Science“ im forstlichen Monitoring derzeit nicht ausgeschöpft wird, aber andererseits mit denjenigen Nutzern, die Biodiversitätsbeobachtungen auf Twitter teilen, eine große Zahl von Individuen mit einem Interesse an Umweltbeobachtungen zur Verfügung steht, die auf der Basis ihres dokumentierten Interesses unter Umständen für bewusst geplante „Citizen Science“-Projekte mobilisiert werden könnten. Zusammenfassend dokumentiert diese Studie, dass soziale Medien eine wertvolle Quelle für Umweltinformationen allgemein sind und eine verstärkte Untersuchung verdienen, letztlich mit dem Ziel, operative Systeme zur Unterstützung von Risikobewertungen in Echtzeit zu entwickeln.

Predatory Ground beetles (Coleoptera: Carabidae) and Lady beetles (Coleoptera: Coccinellidae) are two of the most diverse groups found in wheat agroecosystems, globally. These groups are important from both an economic and ecological perspective due to their natural services provision. The effect of wheat agroecosystem management on species diversity, abundance, biomass and composition in South Africa is not yet documented, and there is no existing data indicating which predatory carabid and coccinellid species provides essential ecosystem services and bioindicator roles. Therefore, we examined the effects of organic, conventional and intercropped agroecosystems on ground beetle and lady beetle abundance, dried weight (biomass), composition and diversity. Sampling of wheat agroecosystems was conducted in three systems i.e. organic, conventional and organic intercropped. Post-hoc Tukey test indicated a statistically significant difference between species diversity, biomass and abundance in organic and intercropped systems compared to the conventional systems. Regression analysis indicated significant positive correlation between aphid’s density and predatory carabid and coccinellid beetles in the intercropped systems. Amongst the weather factors temperature influenced aphid density and carabid and coccinellid beetles’ abundance. PCA (Principal Component Analysis) revealed significant positive correlation between individual biomass and cropping system. Conventional system showed a negative correlations with carabid and coccinellid individual biomass. We found that some carabid and coccinellid species can be used to measure the quality of agroecosystems. This study provides a fundamental basis for identification and monitoring of carabid and coccinellid species and their role as bioindicators of ecological disturbance. The identified bioindicator species in this study can assist in developing conservation and biomonitoring strategies within agroecosystems. / Agriculture and  Animal Health / M. Sc. (Agriculture)