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1
Akhani, Hossein. "Plant biodiversity of Golestan National Park, Iran /." Linz : Biologiezentrum des OÖ. Landesmuseum, 1998. http://www.gbv.de/dms/bs/toc/246607068.pdf.
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Joyce, Christopher Brian. "Management of European floodplain grasslands for plant biodiversity." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/6988.
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European floodplain grasslands are characterized by periodic flooding and regular management, usually cutting and grazing as part of an agricultural system. Past losses and ecological degradation have been due largely to river regulation and either agricultural intensification or abandonment and have resulted in a substantial reduction in area across Europe. Nevertheless, the remaining resource supports considerable biodiversity and a high level of biological production. A better quantitative understanding of the functioning of these grasslands is required in order to establish effective conservation management within a sustainable land use system. The thesis examines the impact of key management factors on three important functional characteristics of the biodiversity of floodplain plant communities, namely plant diversity (measured by species diversity), cover (%) and primary production (above-ground biomass), on two floodplain grasslands of the River Trent, UK and a third on the the Luznice river, the Czech Republic. Field investigations of the effects of cutting, grazing, cessation of management, the influence of floodborne litter, and the impact of fertilizer nitrogen were undertaken over periods of between one and three seasons. These demonstrated that floodplain grassland plant communities are sensitive to variations in management and that impacts on communities are mediated particularly through effects on plant competition. Productive competitive species were encouraged both by abandonment and fertilizer application whereas cutting and grazing management, and the imposition of litter, favoured stress-tolerating perennials. Species diversity decreased both with high inputs of litter and additions of fertilizer. Plant community responses and competitive strategies of key species are discussed in the context of biodiversity conservation, ecological restoration and management of European floodplain grasslands.
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Smith, Ross L. "Invasive alien plant species of The Bahamas and biodiversity management." Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1275062320.
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Perron, Mary Ann. "The Value of Urban Ponds for Odonata and Plant Biodiversity." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40522.
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Urbanization involves the conversion of natural areas to impervious surfaces, which can lead to an increase in the frequency and severity of flood events in cities. To mitigate flood risk, stormwater ponds are constructed to manage urban runoff. Stormwater ponds can also be colonized by wildlife, but their suitability as habitat is disputed due to potential toxicological risks. This study assessed the suitability of stormwater ponds as habitat for the bioindicators Odonata (dragonflies and damselflies) and determined environmental factors that impact their community structure. Odonata (adults, nymphs and exuviae) were sampled at 41 stormwater ponds and 10 natural reference ponds across the National Capital Region of Canada, with a subset of ponds sampled over four years (2015-2018). Plant communities, water quality and surrounding land cover were analyzed at each pond to determine their impacts on Odonata community structure. Overall, stormwater ponds had lower Odonata abundance and a greater variation in species richness and community structure compared to natural ponds but had comparable dragonfly reproduction rates. Plants were the most significant driver of Odonata communities, as stormwater ponds with a high richness of native wetland plants had higher Odonata abundance and community structures similar to natural ponds. Water quality was the second most important driver of Odonata communities with dragonflies showing greater sensitivity to urban contaminants than damselflies. While stormwater ponds had higher concentrations of trace elements than natural ponds (e.g. Ni, V, As), concentrations were generally below toxic levels for all elements except copper and chloride, the latter likely an input from winter road salting. Surrounding land cover was the least important factor affecting Odonata communities. In conclusion, this research demonstrated the importance of local-scale factors related to plants and water quality in sustaining Odonata communities and specifies recommendations for stormwater pond design and maintenance that enhance urban biodiversity.
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Knapp, Sonja. "Plant biodiversity in urbanized areas analyses of plant functional traits in space and time, plant rarity and phylogenetic diversity." Wiesbaden Vieweg + Teubner, 2009. http://d-nb.info/995192685/04.
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Van, der Vyver Marius Lodewyk. "Restoring the biodiversity of canopy species within degraded spekboom thicket." Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/1564.
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I investigated the return of plant canopy diversity to degraded spekboom thicket landscapes under restoration treatment. I attempted the reintroduction of five nursery propagated and naturally-occurring plant species in severely degraded Portulacaria afra Jacq. (spekboom) dominated thickets that have been subjected to a restoration method involving the planting of dense rows of P. afra truncheons for various time periods and also in degraded and intact thickets. I also planted nursery propagated P. afra cuttings. An average of 30 propagules of each species, were planted in each of the chosen areas in two distinct seasons that exhibited distinct rainfall peaks. Sixteen propagules of P. afra were also planted in each treatment only once. Propagules of the two thicket woody canopy species (S. longispina and P. capensis) showed a total survival of 1% and 9%, respectively. Survival of L. ferocissimum and R. obovatum was 19% and 70% and all propagules of P. afra survived. Analyses showed that survival is primarily tied to a species effect, with R. obovatum and P. afra showing significantly better survival than the other species. Within the other surviving few species a significant preference for overhanging canopy cover was observed. The results show little significance of restoration treatment for propagule survival, suggesting that a range of conditions is needed for the successful establishment of canopy species that likely involves a microclimate and suitable substrate created by canopy cover and litter fall, combined with an exceptional series of rainfall events. I found that the high costs involved with a biodiversity planting endeavour, and the low survival of propagules of thicket canopy plant species (P. afra excepted), renders the proposed biodiversity planting restoration protocol both ecologically and economically inefficient. Restoration success involves the autogenic regeneration of key species or functional groups within the degraded ecosystem. Heavily degraded spekboom-dominated thicket does not spontaneously regenerate its former canopy species composition and this state of affairs was interpreted in terms of a state-and-transition conceptual model. Floristic analyses of degraded, intact and a range of stands under restoration treatment for varying time periods at two locations in Sundays Spekboomveld revealed that the stands under restoration are progressively regenerating canopy species biodiversity with increasing restoration age, and that intact sites are still the most diverse. The high total carbon content (TCC) measured within the older restored stands Rhinosterhoek (241 t C ha-1 after 50 years at a depth of 50 cm) rivals that recorded for intact spekboom thickets, and the number of recruits found within older restored sites rivals intact sites sampled. 2 The changes recorded in the above- and belowground environments potentially identify P. afra as an ecosystem engineer within spekboom dominated thickets that facillitates the build-up of carbon above- and belowground and the accompanying changes in soil quality and the unique microclimate aboveground, which enables the hypothetical threshold of the degraded state to be transcended. This restoration methodology is accordingly considered efficient and autogenic canopy species return was found to be prominent after a period of 35-50 years of restoration treatment.
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Martinez, Araneda Camila. "Plant phylogeography in southern South America." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5041.
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This thesis is a phylogeographic investigation into plant species from Patagonia, and aims to infer their past distributions from the study of genealogical lineages. These species have gone through several events such as glacial periods, volcanism and topographical change which are expected to contribute to the divergence of genetic lineages by shaping distributions, isolating populations and therefore changing their genetic structure. So understanding how these processes have affected populations is important to get information on how the biodiversity in the region has been assembled, to identify hotspots of intra-specific diversity and therefore to establish potential conservation priorities. Several multi-species phylogeographic studies have been done in the northern hemisphere, but only few are published for South America and even less for the studied area. Patagonia is an area of a great interest because is the only area in the southern hemisphere apart from Antarctica that have been covered buy a thick layer of ice within the glacial periods. It has high levels of endemism, due to its natural boundaries and environmental processes, and is a biodiversity hotspot for conservation. Its varied topography (two big mountain ranges with a north-south distribution divided by a low flat area) also makes Patagonia interesting to study, due to the likelihood of this impacting on phylogeographic patterns. This study encompass seven different Patagonian species of which one is a range restricted conifer and the rest are all angiosperms and include trees, shrubs and herbs with a broad distributions. The reason why I have chosen so many different species is to look for general phylogeographic patterns in species in this region. The thesis was constructed in five chapters. The first is an introductory chapter that provides background to the study system and concepts. Chapters 2, 3, and 4 are empirical phylogeographic studies. These are written as self-contained chapters with the intention that each will be submitted as a separate paper. This leads to some repetition between chapters, but this is intentional as each will need to ‘stand alone’ when submitted for publication. Chapter 2 is a general investigation into five different Patagonian plant species: Discaria chacaye, Donatia fascicularis, Escallonia virgata, Tepualia stipularis and Weinmannia trichosperma. Chapter 3 describes the phylogeographic structure of Gentianella magellanica an annual, cold tolerant species with a wide distribution throughout Patagonia. This species was treated separately and in more detail than the previous five species due to its marked phylogeographic structure. Chapter 4 describes the phylogeographic structure of a Chilean endemic conifer Prumnopitys andina. This has a small distribution in the Andes and only one known population in the coastal cordillera. It was treated separately due to its restricted distribution and different mode of chloroplast inheritance (paternal). Chapter 5, is a general summary, bring all of the results together and giving a wider explanation of the phylogeographic patterns for all species and an outline of future research areas.
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Brandt, Erika. "Relating Plant Spatial Pattern, Plant Biodiversity, and Ecosystem Function to Management Practices in Experimental Restored Wetlands." Oberlin College Honors Theses / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1368092195.
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Wilson, Frederick. "Factors affecting the species richness of old permanent semi-natural grasslands in North-East Scotland." Thesis, University of Aberdeen, 2003. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU173020.
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The successful management for conservation and restoration of semi-natural ecosystems may be achieved only after the factors which regulate plant biodiversity and species composition have been identified. This study investigates the floristic composition and site characteristics of old permanent semi-natural grasslands in North-east Scotland and tests using pot and field experiments the role of soil fertility in determining vascular plant species richness, relative abundance and dynamics of communities. Results from field surveys show that, of the site characteristics quantified, vascular plant species richness is most strongly correlated (negative relationship) with extractable soil phosphorus. Where species richness is high (>40 in a study stand and >17 in a 1 m2 quadrat) extractable soil phosphorus levels (determined by ammonium acetate-acetic acid/polyacrylamide solution extraction and using inductively coupled radio frequency plasma spectrometry by the atomic emission method) are consistently very low (<1.9 mg 1-1 soil) by local agricultural standards. In pot experiments using soil from a site where high species richness is maintained, the loss of forb and graminoid species from synthesised communities may be shown to increase along a nutrient gradient created by incorporating increments of phosphorus. Despite a general increase in the above ground biomass of species which survive, those with the ability to form nitrogen-fixing nodules grow to dominate the community. By comparison, a nutrient gradient created by the incorporation of potassium has little effect on the species richness of synthesised communities. At field sites where the level of extractable soil phosphorus approaches that above which species-rich semi-natural grassland communities are not found to exist, the addition of nitrogen leads to species loss through the dominance of graminoid species. This effect may be intensified by applying phosphorus.
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Schmidtke, Andrea. "Biodiversity effects on the performance of terrestrial plant and phytoplankton communities." Phd thesis, Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2009/3893/.
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Die Ökosysteme unserer Erde sind durch das rasante Artensterben infolge von Umweltveränderungen durch den Menschen und des globalen Klimawandels stark betroffen. Mit den Auswirkungen dieses Artenverlustes und der damit einhergehenden Veränderung der Diversität beschäftigt sich die heutige Biodiversitätsforschung. Spezieller wird der Effekt der Diversität auf Ökosystemprozesse wie beispielsweise den Biomasseaufbau von Primärproduzenten oder der Resistenz einer Gemeinschaft gegen die Einwanderung neuer Arten untersucht. Die Quantifizierung des Einflusses der Diversität auf die Primärproduktion und das Verständnis der zugrunde liegenden Mechanismen ist von besonderer Wichtigkeit. In terrestrischen Pflanzengemeinschaften wurde bereits ein positiver Diversitätseffekt auf die Gemeinschaftsbiomasse beobachtet. Dies wird hauptsächlich durch den Komplementaritäts- und/oder den Dominanzeffekt erklärt. Die Komplementarität zwischen Arten ist beispielsweise bei Unterschieden in der Ressourcenausnutzung gegeben (z.B. unterschiedliche Wurzeltiefen). Diese kann zu einer besseren Nährstoffausnutzung in diverseren Gemeinschaften führen, die letztlich deren höhere Biomassen erklärt. Der Dominanzeffekt hingegen beruht auf der in diverseren Gemeinschaften höheren Wahrscheinlichkeit, eine hochproduktive Art anzutreffen, was letztlich die höhere Biomasse der Gemeinschaft verursacht.
Diversitätseffekte auf Ökosystemprozesse wurden bisher hauptsächlich auf der Gemeinschaftsebene untersucht. Analysen über die Reaktionen, die alle Arten einer Gemeinschaft einschließen, fehlen bisher. Daher wurde der Einfluss der Diversität auf die individuelle Performance von Pflanzenarten innerhalb des Biodiversitätsprojektes „Das Jena Experiment“ untersucht. Dieses Experiment umfasst 60 Arten, die charakteristisch für Mitteleuropäische Graslandschaften sind. Die Arten wurden in die 4 funktionellen Gruppen Gräser, kleine Kräuter, große Kräuter und Leguminosen eingeteilt. Im Freilandversuch zeigte sich, dass mit steigender Artenzahl die individuelle Pflanzenhöhe zunahm, während die individuelle oberirdische Biomasse sank. Der positive Diversitätseffekt auf die pflanzliche Gemeinschaftsbiomasse kann folglich nicht auf der individuellen oberirdischen Biomassezunahme beruhen. Überdies reagierten die einzelnen funktionellen Gruppen und sogar die einzelnen Arten innerhalb einer funktionellen Gruppe unterschiedlich auf Diversitätsveränderungen. Folglich ist zu vermuten, dass einige Ökosystemprozesse auf Gemeinschaftsebene durch die Reaktionen von bestimmten funktionellen Gruppen bzw. Arten hervorgerufen werden.
Diversitätseffekte auf Gemeinschaftsbiomassen wurden bislang hauptsächlich mit terrestrischen Pflanzen und weniger mit frei-schwebenden Algenarten (Phytoplankton) erforscht. Demzufolge wurde der Einfluss der Diversität auf die Biomasse von Phytoplankton-Gemeinschaften experimentell untersucht, wobei es sowohl zu negativen als auch positiven Diversitätseffekten kam. Eine negative Beziehung zwischen Diversität und Gemeinschaftsbiomasse zeigte sich, wenn schnell-wüchsige Algenarten nur geringe Biomassen in Mono- und Mischkultur aufbauten. Die vorhandenen Nährstoffe in der Mischkultur wurden von den schnell-wüchsigen Arten monopolisiert und folglich standen sie den langsam-wüchsigen Algenarten, welche viel Biomasse in Monokultur aufbauten, nicht mehr zur Verfügung. Zu einem positiven Diversitätseffekt auf die Gemeinschaftsbiomasse kam es, wenn die Artengemeinschaft eine positive Beziehung zwischen Wachstumsrate und Biomasse in Monokultur zeigte, sodass die schnell-wüchsige Algenarten viel Biomasse aufbauten. Da diese schnell-wüchsigen Algen in der Mischkultur dominant wurden, bestand die Gemeinschaft letztlich aus hoch-produktiven Algenarten, was zu einer erhöhten Gesamtbiomasse führte. Diese beiden Versuchsansätze verdeutlichen Mechanismen für die unterschiedlichen Reaktionen der Gemeinschaften auf Diversitätsveränderungen, welche auch für terrestrische Pflanzengemeinschaften gefunden wurden.
Ein anderer wichtiger Ökosystemprozess, der von der Diversität beeinflusst wird, ist die Anfälligkeit von Gemeinschaften gegenüber invasiven Arten (Invasibilität). Die Invasibilität wird von einer Vielzahl von Faktoren beeinflusst und demzufolge wurde der Effekt der Diversität und der Produktivität (Nährstoffgehalt) auf die Invasibilität von Phytoplankton-Gemeinschaften in An- und Abwesenheit eines Herbivoren untersucht. Die zwei funktionell unterschiedlichen invasiven Arten waren die Blaualge Cylindrospermopsis raciborskii (schlecht fressbar) und der Phytoflagellat Cryptomonas sp. (gut fressbar). Es zeigte sich, dass der Fraßdruck, welcher selber durch die Produktivität beeinflusst wurde, einen bedeutenden Effekt auf die Invasibilität von Phytoplankton-Gemeinschaften hat. Die funktionellen Eigenschaften der invasiven und residenten Arten waren zudem bedeutender als die Artenzahl.To date, positive relationships between diversity and community biomass have been mainly found, especially in terrestrial ecosystems due to the complementarity and/or dominance effect. In this thesis, the effect of diversity on the performance of terrestrial plant and phytoplankton communities was investigated to get a better understanding of the underlying mechanisms in the biodiversity-ecosystem functioning context. In a large grassland biodiversity experiment, the Jena Experiment, the effect of community diversity on the individual plant performance was investigated for all species. The species pool consisted of 60 plant species belonging to 4 functional groups (grasses, small herbs, tall herbs, legumes). The experiment included 82 large plots which differed in species richness (1-60), functional richness (1-4), and community composition. Individual plant height increased with increasing species richness suggesting stronger competition for light in more diverse communities. The aboveground biomass of the individual plants decreased with increasing species richness indicating stronger competition in more species-rich communities. Moreover, in more species-rich communities plant individuals were less likely to flower out and had fewer inflorescences which may be resulting from a trade-off between resource allocation to vegetative height growth and to reproduction. Responses to changing species richness differed strongly between functional groups and between species of similar functional groups. To conclude, individual plant performance can largely depend on the diversity of the surrounding community. Positive diversity effects on biomass have been mainly found for substrate-bound plant communities. Therefore, the effect of diversity on the community biomass of phytoplankton was studied using microcosms. The communities consisted of 8 algal species belonging to 4 functional groups (green algae, diatoms, cyanobacteria, phytoflagellates) and were grown at different functional richness levels (1-4). Functional richness and community biomass were negatively correlated and all community biomasses were lower than their average monoculture biomasses of the component species, revealing community underyielding. This was mainly caused by the dominance of a fast-growing species which built up low biomasses in monoculture and mixture. A trade-off between biomass and growth rate in monoculture was found for all species, and thus fast-growing species built up low biomasses and slow-growing species reached high biomasses in monoculture. As the fast-growing, low-productive species monopolised nutrients in the mixtures, they became the dominant species resulting in the observed community underyielding. These findings suggest community overyielding when biomasses of the component species are positively correlated with their growth rates in monocultures. Aquatic microcosm experiments with an extensive design were performed to get a broad range of community responses. The phytoplankton communities differed in species diversity (1, 2, 4, 8, and 12), functional diversity (1, 2, 3, and 4) and community composition. The species/functional diversity positively affected community biomass, revealing overyielding in most of the communities. This was mainly caused by a positive complementarity effect which can be attributed to resource use complementarity and/or facilitative interaction among the species. Overyielding of more diverse communities occurred when the biomass of the component species was correlated positively with their growth rates in monoculture and thus, fast-growing and high-productive species were dominant in mixtures. This and the study mentioned above generated an emergent pattern for community overyielding and underyielding from the relationship between biomass and growth rate in monoculture as long as the initial community structure prevailed. Invasive species can largely affect ecosystem processes, whereas invasion is also influenced by diversity. To date, studies revealed negative and positive diversity effects on the invasibility (susceptibility of a community to the invasion by new species). The effect of productivity (nutrient concentration ranging from 10 to 640 µg P L-1), herbivory (presence/absence of the generalist feeder) and diversity (3, 4, 6 species were randomly chosen from the resident species pool) on the invasibility of phytoplankton communities consisting of 10 resident species was investigated using semi-continuous microcosms. Two functionally diverse invaders were chosen: the filamentous and less-edible cynaobacterium C. raciborskii and the unicellular and well-edible phytoflagellate Cryptomonas sp. The phytoflagellate indirectly benefited from grazing pressure of herbivores whereas C. raciborskii suffered more from it. Diversity did not affect the invasibility of the phytoplankton communities. Rather, it was strongly influenced by the functional traits of the resident and invasive species.
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Oikawa, Junko. "Future role of living plant collections in gardens for biodiversity conservation." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314314.
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Harper, Leah Wheelbarger. "Plant Biodiversity across Three Successional Stages in Forests of Southern Illinois." OpenSIUC, 2020. https://opensiuc.lib.siu.edu/theses/2794.
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Since the time of European settlement, land-use history, management practices, the introduction of non-native invasive species (NNIS), and climate change have dramatically changed the successional pathways of Southern Illinois forests. Biodiversity is considered essential for ecosystem health and resiliency, so understanding the impact theses forest changes have on biodiversity is necessary to guide future management decisions. This study was conducted at Touch of Nature Environmental Center (TONEC) in Southern Illinois using the Shannon diversity index (H') to compare the levels of biodiversity in the overstory, shrub, seedling, and herbaceous layers across early, mid, and mature successional stages. Twenty plots were randomly placed within early, mid, and mature forest successional stages for a total of 60 plots. Four circular nested vegetation plots were recorded at each plot location. In the overstory plots (area 314.16 m2), woody stems above 6.5 cm diameter at breast height (dbh), age class, and crown were all recorded. In the shrub layer (area 28.27 m2), all woody stems between 2.5 and 6.5 cm dbh were recorded, while in the seedling layer (area 3.14 m2), all woody stems < 1 cm dbh were recorded. In the herbaceous layer, (area 1 m2) species were measured by percent cover. Shannon diversity index (H') was calculated for each plot. When vegetation layers were combined and mean H' within forest successional stages were compared, no differences were found. However, when successional stages were combined within each vegetation layer, the shrub layer had the least H' increasing to seedling, increasing again to overstory and herbaceous; these being equal. When breaking down the vegetation layers separately and comparing H' across successional stages within each, both the overstory and shrub layers had no difference. Early successional was the least diverse in seedling, rising to mid and mature, which were equal. The herbaceous layer showed an opposite trend with early having the highest H' decreasing to mid and decreasing again to mature. Finally looking at the differences across vegetation layers within early, mid, and mature successional stages. Early-successional had the most variability with the highest H' in herbaceous; this decreased progressively to overstory then to shrub and seedling, which were equal. In mid-successional plots, overstory, seedling, and herbaceous layers were equal with H' decreasing in shrub. In mature plots, all vegetation layers had the same H'. Across all vegetation layers, the highest percentage of NNIS was in early-successional, followed by mid, with notably less found in mature forest. Even in instances where H' values were the same, species composition across forest successional stages were quite different. While overall biodiversity is the same across successional stages, differences in H' can be seen when looking at the vegetation layers. Management should focus on removing NNIS in the early and mid-successional forests paying particular attention to the shrub layer, which has the overall lowest H' with the most dramatic differences in composition and the presence of NNIS across all successional stages. Also of concern is the low H' in the seedling layer in early-successional forest, which reduces the likelihood of successful regeneration of these hardwood stands in the future.
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Neloy, Md Naim Ud Dwla. "Validation of theoritical approach to measure biodiversity using plant species data." Thesis, Högskolan i Skövde, Institutionen för biovetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-19431.
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Measuring Biodiversity is an important phenomenon to serve best to our ecology and also keep environment sound. Variety of life on different levels, like an ecosystem, life forms on a site, landscape collectively known as Biodiversity. Species richness and evenness combine measures as Biodiversity. Separate formula, index, equation are widely using to measure Biodiversity in each level. Swedish Environmental Protection Agency aimed to establish an index that consists of landscape functionality and landscape heterogeneity. For landscape functionality assessment, there BBCI (Biotope biodiversity Capacity index) is going to use. High BBCI indicates a high biodiversity for each biotope. However, empirically estimate species richness how much matched with BBCI that not been evaluated. The aim of this paper to see the relationship between empirical estimated Biodiversity and BBCI. A relationship between Shannon diversity index and BBCI also ran to see the matches between them. Collect the empirical data from selected 15 landscapes using Artportalen.se and sort the data for further calculation. Results showed that there was a strong positive relationship between empirical estimated Biodiversity and BBCI. Again Shannon diversity index and BBCI also demonstrated a positive correlation between them. It showed BBCI could explain 60%-69% of species richness data and 17%-22% of Shannon diversity index. It indicates the acceptance of theoretical study of measure Biodiversity.
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Imran, Hafiz Ali. "Remote Sensing Tools for Monitoring Grassland Plant Leaf Traits and Biodiversity." Doctoral thesis, Università degli studi di Trento, 2022. http://hdl.handle.net/11572/329592.
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Grasslands are one of the most important ecosystems on Earth, covering approximately one-third of the Earth’s surface. Grassland biodiversity is important as many services provided by such ecosystems are crucial for the human economy and well-being. Given the importance of grasslands ecosystems, in recent years research has been carried out on the potential to monitor them with novel remote sensing techniques. Improved detectors technology and novel sensors providing fine-scale hyperspectral imagery have been enabling new methods to monitor plant traits (PTs) and biodiversity.
The aims of the work were to study different approaches to monitor key grassland PTs such as Leaf Area Index (LAI) and biodiversity-related traits. The thesis consists of 3 parts: 1) Evaluating the performance of remote sensing methods to estimate LAI in grassland ecosystems, 2) Estimating plant biodiversity by using the optical diversity approach in grassland ecosystems, and 3) Investigating the relationship between PTs variability with alpha and beta diversity for the applicability of the optical diversity approach in a subalpine grassland of the Italian Alps
To evaluate the performance of remote sensing methods to estimate LAI, temporal and spatial observations of hyperspectral reflectance and LAI were analyzed at a grassland site in Monte Bondone, Italy (IT-MBo). In 2018, ground temporal observations of hyperspectral reflectance and LAI were carried out at a grassland site in Neustift, Austria (AT-NEU). To estimate biodiversity, in 2018 and 2019 a floristics survey was conducted to determine species composition and hyperspectral data were acquired at two grassland sites: IT-MBo and University of Padova’s Experimental Farm, Legnaro, Padua, Italy (IT-PD) respectively. Furthermore, in 2018, biochemistry analysis of the biomass samples collected from the grassland site IT-MBo was carried out to determine the foliar biochemical PTs variability.
The results of the thesis demonstrated that the grassland spectral response across different spectral regions (Visible: VIS, red-edge: RE, Near-infrared: NIR) showed to be both site-specific and scale-dependent. In the first part of the thesis, the performance of spectral vegetation indices (SVIs) based on visible, red-edge (RE), and NIR bands alongside SVIs solely based or NIR-shoulder bands (wavelengths 750 - 900 nm) was evaluated. A strong correlation (R2 > 0.8) was observed between grassland LAI and both RE and NIR-shoulder SVIs on a temporal basis, but not on a spatial basis. Using the PROSAIL Radiative Transfer Model (RTM), it was demonstrated that grassland structural heterogeneity strongly affects the ability to retrieve LAI, with high uncertainties due to structural and biochemical PTs co-variation.
In the second part, the applicability of the spectral variability hypothesis (SVH) was questioned and highlighted the challenges to use high-resolution hyperspectral images to estimate biodiversity in complex grassland ecosystems. It was reported that the relationship between biodiversity (Shannon, Richness, Simpson, and Evenness) and optical diversity metrics (Coefficient of variation (CV) and Standard deviation (SD)) is not consistent across plant communities. The results of the second part suggested that biodiversity in terms of species richness could be estimated by optical diversity metrics with an R2 = 0.4 at the IT-PD site where the grassland plots were artificially established and are showing a lower structure and complexity from the natural grassland plant communities. On the other hand, in the natural ecosystems at IT-MBo, it was more difficult to estimate biodiversity indices, probably due to structural and biochemical PTs co-variation. The effects of canopy non-vegetative elements (flowers and dead material), shadow pixels, and overexposed pixels on the relationship between optical diversity metrics and biodiversity indices were highlighted.
In the third part, we examined the relationship between PTs variability (at both local and community scales, measured by standard deviation and by the Euclidean distances of the biochemical and biophysical PTs respectively) and taxonomic diversity (both α-diversity and β-diversity, measured by Shannon’s index and by Jaccard dissimilarity index of the species, families, and functional groups percent cover respectively) in Monte Bondone, Trentino province, Italy. The results of the study showed that the PTs variability metrics at alpha scale were not correlated with α-diversity. However, the results at the community scale (β-diversity) showed that some of the investigated biochemical and biophysical PTs variations metrics were associated with β-diversity. The SVH approach was also tested to estimate β-diversity and we found that spectral diversity calculated by spectral angular mapper (SAM) showed to be a better proxy of biodiversity in the same ecosystem where the spectral diversity failed to estimate alpha diversity, this leading to the conclusion that the link between functional and species diversity may be an indicator of the applicability of optical sampling methods to estimate biodiversity.
The findings of the thesis highlighted that grassland structural heterogeneity strongly affects the ability to retrieve both LAI and biodiversity, with high uncertainties due to structural and biochemical PTs co-variation at complex grassland ecosystems. In this context, the uncertainties of satellite-based products (e.g., LAI) in monitoring grassland canopies characterized by either spatially or temporally varying structure need to be carefully taken into account. The results of the study highlighted that the poor performance of optical diversity proxies in estimating biodiversity in structurally heterogeneous grasslands might be due to the complex relationships between functional diversity and biodiversity, rather than the impossibility to detect functional diversity with spectral proxies.
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Rai, Upkar. "Characterisation of plant biodiversity in darjiling hills using remote sensing techniques." Thesis, University of North Bengal, 2006. http://hdl.handle.net/123456789/843.
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Fabricius, Christo 1956. "The impact of land use on biodiversity in xeric succulent thicket, South Africa." Doctoral thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/9512.
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Bibliography: leaves 100-114.Human-induced land management practices are key factors which influence the dynamics of landscapes, land elements and biotic communities in Xeric Succulent Thicket, a notoriously fragile and low resilience ecosystem in the Eastern Cape, South Africa. In its natural state this vegetation type is characterized by a continuous mosaic of clumps of diverse woody shrubs in a matrix of grass, hardy dwarf shrubs and bare ground. When indigenous herbivores are replaced by domestic livestock at unsustainable stocking rates, the ratio of clump to interclump areas decreases. This has impacts on biodiversity at the landscape level, and affects the composition and species richness of plant, arthropod and reptile communities and fungal symbionts. The study has two main objectives: 1) to detennine the local-level effects of different types of land use on biodiversity in Xeric Succulent Thicket; and 2) to better understand the factors which affect biodiversity in different taxonomic groups and at different spatial scales, so that the preservation function of protected areas could be enhanced. The key questions which are addressed in the thesis are what does 'biodiversity' mean, and what are its different dimensions in Xeric Succulent Thicket; what roles do protected areas and other lands play in preserving biodiversity, how are different taxonomic groups affected by different types of land use; and how can biodiversity be monitored and measured? . The regional 'conservation landscape' is seen as the protected area plus the land immediately adjoining it, and is viewed as an integrated mosaic of anthropogenic landscapes (land management units), land elements (patches within landscapes). producer communities (assemblages of interacting plant species), consumer communities (assemblages of interacting herbivores and predators) and soil microorganisms. From a process point of view, the research relates the intensity of disturbance, mainly as a result of herbivory, to landscape complexity, the structure of land elements, and the species richness of producers and consumers within land elements. The patterns which emerge are interpreted in the context of ecosystem functioning, from the point of view of a practicing conservation biologist.
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Davie, Kim. "The biodiversity and epidemiology of potato virus Y (PVY) in Scotland." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/27766/.
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Potato virus Y (PVY) is considered to be the most serious viral pathogen that affects potato crops worldwide and can cause substantial yield losses. PVY exists as a complex of strains that can be distinguished on the basis of their biology, serology and genome analysis. In recent decades novel recombinant PVYN strains have emerged that can cause Potato Tuber Necrotic Ringspot Disease (PTNRD). It is therefore important to understand the potential threat to the Scottish seed potato industry. This molecular nature of PVY isolates in Scotland was established through the use of partial sequencing, revealing a predominance of isolates belonging to the molecular EU-NTN clade (ca 75%). Assessing the biological characteristics of selected isolates indicated that most isolates in Scotland belong to the biological PVYN type, however PVYE is also present. Molecular analysis of a PVYE isolate has shown that identifying the molecular determinants for vein necrosis production in tobacco is complex. Although it has not been reported from the field in Scotland, PTNRD initiation is possible with most PVYN isolates under optimal climatic conditions. Field trials suggest that PVYEU-NTN is more efficiently transmitted by aphids across a growing season than PVYNA-NTN and PVYO, with a higher than expected proportion of tubers infected with the PVYEU-NTN isolate. This suggests that once plants are inoculated with the virus, PVYEU-NTN isolates are more likely to infect progeny tubers. Taken together, the outcomes of this project should provide a better understanding as of PVY molecular nature in Scotland its pathogenicity and epidemiology with the view to understanding why PVYN variants have become an important threat for the seed potato industry both in Scotland and worldwide.
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Patrick, L. Brian. "Fertilization and plant litter effects on the plant and epigeal arthropod communities." [Kent, Ohio] : Kent State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1259588844.
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Thesis (Ph.D.)--Kent State University, 2009.Title from PDF t.p. (viewed April 14, 2010). Advisor: Mark W. Kershner. Keywords: biodiversity; nitrogen; fertilization; plant litter; trophic dynamics; epigeal community. Includes bibliographical references.
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Maguire, Victoria. "Immunogold labelling of TIP proteins in the resurrection plant Craterostigma plantagineum." Thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/26509.
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CAVALLORO, VALERIA. "Exploiting the Pavia territory plant biodiversity for the discovery of proteasome modulators." Doctoral thesis, Università degli studi di Pavia, 2022. http://hdl.handle.net/11571/1449465.
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Louw, Merika. "Propagation and stress physiology of selected Subtropical Thicket species : towards increasing biodiversity at rehabilitation sites." Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1021115.
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Sundays Thicket and Spekboomveld vegetation in the Eastern Cape have experienced intensive and extensive degradation due to over-browsing by domestic stock. The Subtropical Thicket Restoration Project aims to take advantage of the high carbon sequestration potential of Portulacaria afra (Spekboom) and other Thicket species, to rehabilitate degraded Thicket by restoring biodiversity and ecosystem services, create job opportunities and socio-economic upliftment in local communities, and promote the trade of carbon credits generated by planting and „farming‟ with Spekboom truncheons, rather than domestic stock. Plant material (seeds and length of stem) was sourced from the farm Krompoort, outside Uitenhage in the Eastern Cape. The effectiveness of four different rooting media i.e. plain pool filter sand and 1:1 mixtures of pool filter sand with perlite, potting soil and Thicket soil, on the rooting of ten Thicket species, were tested. Species with the greatest percentage strike and mean root length on stem cuttings were succulent species, Crassula ovata (84 percent strike) and Portulacaria afra (97 percent), as was expected. The application of rooting hormone Seradix© No. 3 did not significantly promote cutting strike or increase mean root length in C. ovata and P. afra. Woody canopy shrub species with the greatest cutting strike and mean root length, overall, were Rhigozum obovatum (24 percent), Lycium cinereum and L. oxycarpum (21 percent), and Searsia longispina (19 percent). These species, as well as Grewia robusta (4 percent), are considered „easy-to-root‟ species, or of sufficient functional value in terms of their spinescence, flower and fruit production, and soil-binding capabilities. Very low percentage strike (<1 percent) and mean root length were achieved in Azima tetracantha, Carissa bispinosa and Gymnosporia polyacantha subsp. polyacantha. These species are considered unsuitable for propagation for rehabilitation purposes. Crassula ovata, L. cinereum, L. oxycarpum, P. afra and S. longispina cuttings produced longer roots when planted in Thicket soil, the same having been found in R. obovatum cuttings planted in perlite. Thicket soil was, therefore, best at promoting cutting strike and root growth in „easy-to-root‟ species. Plain pool filter sand was the only medium in which A. tetracantha, C. bispinosa and G. robusta, cuttings rooted, and perlite the only medium in which G. polyacantha subsp. polyacantha cuttings rooted. Potting soil did not promote significant cutting strike or root growth in any of the species tested. Physiological variables i.e. photosynthetic efficiency (chlorophyll a fluorescence, Fv/Fm) and stomatal conductance (mmol H2O m-2 s-1) were measured for ten Thicket species, including Portulacaria afra. Control plants were watered well once a week, and treatment plants were dried out for 30 days, rewatered on the 30th day and their recovery from drought stress monitored for a further 17 days. Species that responded poorly to drought stress were Gymnosporia buxifolia and Putterlickia pyracantha. In addition to Portulacaria afra, species that showed the fastest recovery and resprout after rewatering, were: Crassula ovata, Ehretia rigida, Grewia robusta, Lycium ferocissimum, Rhigozum obovatum and Searsia longispina. These species produced the smallest decline in volumetric moisture content of soil, and had the lowest decline in photosynthetic efficiency and stomatal conductance during simulated drought. Unlike C. ovata and P. afra, which are CAM or C3-CAM switching species, mortality of transplants will most likely be high, if not total, during transplantation, as this study was done at lower light and temperature, and higher humidity levels than experienced at rehabilitation sites. This study has shown that the reintroduction of propagated woody canopy shrubs and trees into degraded Thicket sites does not appear to be a practical or economical method of actively restoring biodiversity to rehabilitation sites. As woody climax species have been shown to return to sites planted with Spekboom truncheons through „natural regeneration‟ within approximately 50 years, future research efforts should focus on optimising restoration site selection and planting techniques in order to maximize carbon sequestration potential of planted truncheons, which will, in the long term, result in an environment that can support regeneration of the biodiversity to something resembling intact Thicket.
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Rowe, Rebecca L. "Implications for biodiversity of the deployment of commercial scale short rotation willow coppice." Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/195559/.
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Willow short rotation coppice (SRC) is seen as an important renewable energy source within temperate regions including the UK and its deployment within the agri-environment is supported by a number of goverment policies. Willow SRC represents a significant land use change and its deployment has raised questions regarding the possible impacts on biodiversity and the delivery of ecosystem services. This work assessed the impact of three commercial willow SRC plantations on ecosystem processes through the use of herbivory, decomposition and predation bioassays. Comparisons were also made between the willow SRC plantations and the abundance and diversity of: summer ground flora and winged invertebrates in the alternative land use options of set-aside and cereal crops; predatory ground invertebrates and small mammals in winter wheat and barely. In comparison to cereal crops the willow SRC plantations contained a higher abundance and species richness of ground flora and small mammals, and a higher abundance and family richness of predatory ground invertebrates. Ground flora richness was higher in the set-aside land than within the willow SRC. The ground flora community within the willow SRC was markedly different to both set aside and arable land with a shift from an annual and ruderal to competitive and perennial dominated community. The composition of winged invertebrate Orders also varied between the land uses with higher numbers of Hymenoptera and Hemiptera trapped within the willow SRC plantations than within the arable and set-aside land. No differences were detected on rates of predation on invertebrate prey, seedling herbivory and decomposition between willow SRC and set-aside land. In comparison to cereal crops higher rates of decomposition and higher rates of predation by small mammals in the autumn were recorded in willow SRC. Overall the results suggest that, willow SRC plantations may benefit farm-scale biodiversity by providing a habitat where plants and animals that are uncommon on alternative land use can persist. Moreover positive effects on the species richness of small mammals and the abundance and richness of predatory invertebrates may have positive implication for natural pest control both within willow SRC plantations and possibly on surrounding landscape. Comparisons to set-aside did, however, highlight that willow SRC is not a panacea for all species and care must be taken in the location and fraction of the landscape that is devoted to this crop
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Maholland, Peter D. "Effects of Prescribed Fire on Upland Plant Biodiversity and Abundance in Northeast Florida." UNF Digital Commons, 2015. http://digitalcommons.unf.edu/etd/562.
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Terrestrial ecosystems in the southeastern United States have evolved with fire as a common disturbance and as a result many natural communities require the presence of fire to persist over time. Human development precludes natural fires from occurring within these communities; however, prescribed fire is considered to be a critical tool in the effort to restore fire-dependent ecosystems after decades of fire exclusion. Direct effects of fire on individual floral and faunal species as well as benefits to biodiversity at the landscape (gamma diversity) level have largely been supported in previous research. However, information on the effects of natural and prescribed fire on plant diversity at the local level (alpha diversity) is limited, particularly for southeastern forests. The applicability of the Intermediate Disturbance Hypothesis (IDH), which suggests that the highest levels of biodiversity are found at intermediate levels of disturbance, is also untested for North Florida upland plant communities. This study compared the effects of fire on local scale mean plant species diversity by examining burned and unburned portions of three fire-dependent communities to determine if there is an effect of prescribed fire on in alpha biodiversity. Alpha biodiversity was not significantly different (p=0.433) between burned and unburned fire-dependent plant communities in northern Florida, suggesting that prescribed fire does not affect plant species diversity in these communities and/or the IDH for plant communities is not supported at the time scale tested. However, the application of prescribed fire did result in changes in abundance of species, particularly with species such as Dicanthelium acuminatum, Quercus myrtifolia, and Vaccinium myrsinites, that respond positively to fire, which may have implications for associated faunal diversity.
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Ferreira, Mariana Moreira. "Biodiversity and plant-pollinator interactions in native forest areas of Terceira Island (Azores)." Master's thesis, Universidade de Évora, 2018. http://hdl.handle.net/10174/23061.
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Neste trabalho avaliámos o impacto que a perturbação humana das comunidades da floresta nativa da ilha Terceira (Açores) tem sobre a riqueza específica e nas interações ecológicas entre plantas e polinizadores. Para o efeito selecionámos dois locais emparelhados (um bem conservado e outro degradado), em duas áreas de estudo (Lomba e Pico Galhardo) e analisámos a integridade das redes ecológicas planta-polinizador. Constatámos que nas áreas bem conservadas as interações são dominadas por espécies nativas, enquanto que nas áreas perturbadas, apesar da prevalência de plantas introduzidas, os polinizadores nativos têm um papel relevante. Em cada área houve apenas uma planta que concentrou as visitas dos polinizadores, que na sua maioria pertenceram à ordem Diptera e tiveram hábitos generalistas; Biodiversity and plant-pollinator interactions in native forest areas of Terceira island (Azores)
Abstract: In this work we evaluate the effect of anthropogenic disturbance in native forest communities of Terceira island (Azores) on species richness and on plant-pollinator ecological interactions. We selected paired sampling sites (one well-preserved and one disturbed) in two study areas (Lomba and Pico Galhardo) and we analysed plant-pollinator networks integrity. We found that native species dominate in well-preserved sites whereas in disturbed sites, despite the prevalence of introduced plants, native pollinators play an important role. In each area there was a plant that received most of the insect visits, being these mainly from Diptera order and having generalist behaviour.
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Reimark, Josefin. "How has time and space affected plant biodiversity in the Hjälmö-Lådna archipelago?" Licentiate thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-79230.
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Traditionally European farmland management has declined during the last century, mainlydue to abandonment or intensification. When traditional management is replaced by newmethods many species are negatively affected and often threatened with extinction. In thisthesis, the Stockholm archipelago is used as a platform to study the effects of land use changeover time. The overall aim is to examine how time and space affects plant biodiversity in arural landscape, with focus on heterogeneous pastures. Historical records and maps were interpreted together with aerial photos and used to constructfour time-layers of land use: reflecting the landscape 200 years ago, 100 years ago, 50 yearsago and present. Investigations of plant species richness was conducted in seven habitats; 1)grazed fields, 2) grazed forest edges, 3) grazed forest interior, 4) former grazed fields, 5)former grazed forest edges, 6) former grazed forest interior, and 7) historical pasture islands,on 35 islands in Hjälmö-Lådna archipelago on the east-coast of Sweden. Plant speciesrichness was measured for all plant species and for grassland specialist species at three scales:i) fine-scale diversity (α div), ii) large-scale diversity (γ div ), and iii) spatial turnover (β div).Using Structural Equation Models (SEM) the variation in species diversity and plantcommunity composition was investigated in relation to landscape context, space andmanagement history. The land use change in the Hjälmö-Lådna archipelago followed the general trends on themainland in Sweden and the rest of Europe with loss of traditional managed habitats, such asmeadows or wooded pastures. However, no intensification and large-scale agriculture hasdeveloped on the islands, mainly because of physical limitations, but also because ofeconomical and conservation reasons. Surprisingly, the grazing pressure on the remaininggrazed habitats had not changed notable over the last century; although the study area was notparticularly species rich (highest average was 15 species/ m2 in grazed fields). Adjacenthabitats; field and wood pasture, showed a higher similarity in community composition thanexpected compared to random pairs. Grazing and proportion of openness had a positiveinfluence on species richness and especially on grassland specialists. The variation of totaldiversity at the landscape scale was best explained by the heterogeneity of grazed forest edgesand the local species diversity in fields. The results from the study suggest that grazing is important also in species-poor landscapes,and that it can aid in protecting and promote species-richness also in other types of speciespoorlandscapes. To prevent further loss of biodiversity it is necessary to keep fields andforest edges open with continuous management. To maintain values of high biodiversity andculture in the archipelago it is therefore important that farmers are subsidised by EU tocontinue to grazie heterogeneous habitats and pastures with many trees.
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Pornaro, Cristina. "Effects of wood establishment on plant biodiversity and herbage production of mountain pastures." Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3422525.
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In the past sixty years, the Southern Alps have undergone a tremendous and likely unprecedented change in land-use due to land abandonment in mountain regions. This phenomenon causes a turn of mountain grasslands to forests through the process of natural succession.
Vegetation relevés in eight pastures under forest succession in the Italian Alps were collected at different percentage of wood cover. Moreover, in four of the eight sites, herbage samples were collected at different wood cover levels. In addition, in one site (characterised by Nardus grassland habitat) core samples were collected in order to study root characteristics. Species richness, botanical composition, dry matter production and contents, and root characteristics were taken into account in order to analyze the effect of wood cover on plant diversity, herbage yield and quality, and soil stability.
The effect on specie richness due to this process is different among sites because of differences in environmental factors and human activities. In general species richness decreased with increasing wood cover, and the reduction was more relevant in sites at low altitude. In some sites the effect of reforestation on plant species richness showed a slight increase at low percentage of wood cover followed by a gradual decrease, while in the others the effect displayed a monotonic decrease. Modelling with a generalized linear mixed model suggested that mean annual temperature was the primary determinant of the functional relationship. Differences among sites were not found when botanical composition, and in particular Bray dissimilarity index, was taken into account.
A reduction of dry matter yield was noted in most of the studied sites. Forest succession affected herbage quality decreasing it starting from low percentage of wood cover because of changes in crude protein and fibrous contents.
When root characteristics were analyzed, root length density and average diameter declined at 75% of wood cover increasing the risk of soil erosion.
Based on this results, mountain areas with low relevance for dairy production grazing should be encouraged for preserving both biodiversity and the stability of habitat. The strong effect of temperature on the loss of species richness suggests that the risk increases with lower altitude and stronger exposition towards South. The maintenance of low percentage of wood cover is useful for the habitat ecological value. On the contrary, in mountain areas where dairy production grazing is relevant, the management should be assessed for excluding wood establishment on the grazing surface.Negli ultimi sessant’anni, nell’ambiente alpino ed in particolare nelle Alpi italiane, si è assistito ad un importante e senza precedenti cambiamento d’uso del suolo, dovuto all’abbandono delle zone montane. Questo fenomeno ha causato un avanzamento del bosco su prati e pascoli attraverso un processo naturale di riforestazione. Per questo studio sono stati eseguiti rilievi floristici in otto pascoli montani delle Alpi italiane, soggetti ad avanzamento del bosco. Inoltre, in quattro di questi otto siti sono stati raccolti campioni di foraggio per la determinazione della produttività e della qualità della fitomassa. Infine, in un sito, caratterizzato dalla presenza di habitat a Nardus stricta, sono state raccolte carote di terreno per la caratterizzazione della componente ipogea. In tutti i casi i rilievi e i campionamenti sono stati eseguiti a percentuali crescenti di copertura arboreo-arbustiva. Sono stati considerati i seguenti parametri: numero di specie, composizione botanica, produzione e composizione chimica della sostanza secca nonché densità e diametro medio della radici a diversi livelli di profondità nel terreno, in modo da analizzare l’effetto della copertura arboreo-arbustiva su diversità vegetazionale, produzione e qualità del pascolo e stabilità del suolo. L’effetto sul numero di specie causato dall’avanzamento del bosco è risultato diverso tra i siti a causa delle differenze che intercorrono nei fattori ambientali e nelle attività antropiche. In generale si è assistito ad una diminuzione del numero di specie per effetto dell’avanzamento del bosco, in alcuni siti però è stato osservato un leggero aumento per bassi valori di copertura arboreo-arbustiva. La diminuzione del numero di specie è stata più marcata nei siti ad altitudine inferiore. Usando un modello lineare misto generalizzato, è stato riscontrato che le temperature medie annue sono uno dei fattori che meglio spiegano la diversa relazione tra i siti. L’analisi della composizione floristica mediante l’indice di Bray, ha evidenziato un comportamento simile tra i siti. Nella maggior parte dei siti analizzati si è riscontrata una diminuzione della produzione in sostanza secca per effetto della copertura arborea. Inoltre, già a partire da basse percentuali di copertura arboreo-arbustiva, è stata osservata una diminuzione della qualità della fitomassa prodotta dal pascolo, per effetto di una diminuzione del contenuto di proteina grezza ed un aumento delle fibre. Relativamente alle radici, si è osservato come la densità radicale in lunghezza e il diametro medio diminuissero drasticamente a percentuali di copertura arboreo-arbustiva del 75%, aumentando verosimilmente il rischio di erosione del suolo. Sulla base di questi risultati possiamo dire che nelle regioni montane, laddove la vocazione produttiva (in termini di produzione casearia) è poco rilevante, andrebbe incoraggiato il mantenimento di questi habitat a vantaggio della biodiversità e della stabilità del suolo. Come visto in questo studio, l’effetto della temperatura media annua sulla diminuzione del numero di specie, suggerisce che il rischio di perdita di biodiversità aumenta ad altitudine minore e in aree esposte a sud. Il mantenimento di basse percentuali di alberi o arbusti può essere utile per conservare il valore naturalistico di questo habitat. Al contrario, nelle zone dove la vocazione casearia del pascolo è prevalente, la gestione dovrebbe essere tale da mantenere le superfici a pascolo completamente libere da alberi e arbusti.
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Marshall, Carolyn Bowers. "Effect of plant functional group removal on the soil microbial community diversity and composition." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2865.
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A major objective of biodiversity-ecosystem functioning (BDEF) research is to determine the consequences of species loss, caused both naturally and anthropogenically, on the functioning of ecosystems. The impact of plant species loss on the soil microbial community has not received much attention even though soil microbes influence many important ecosystem functions such as decomposition and nutrient cycling. The objective of this research was to investigate how the functional group composition of the aboveground plant community influenced the belowground microbial community. Plant functional groups (graminoids, legumes and non-leguminous forbs) were removed from a northern grassland system in the Yukon Territory, Canada. One metre square plots had one of the three functional groups removed or left intact as a control and this was crossed with a fertilizer treatment and a fungicide treatment that targeted mycorrhizal fungi. After five seasons (2003-07) of implementing treatments the soil microbial community was analyzed using substrate-induced respiration (SIR, a measure of metabolic diversity) and phospholipid fatty acid analysis (PLFA, a measure of community composition). Plant functional group removal had almost no effect on the soil microbial community. The only response detected was an increase in stress (indicated by the PLFA stress ratio of cy19:0 to 18:1ω7c) which occurred when legumes were removed and fertilizer was not added, indicating that legumes had a positive effect on the nutrient status of microbes. Likewise, soil properties (total carbon, pH, moisture and nutrients) showed limited response to plant removals. Fertilization decreased the metabolic diversity of the soil microbial community. We detected no soil microbial or plant biomass response to the fungicide indicating that mycorrhizae had little influence in this system. Based on the low-productivity of the grassland, and the lack of response in both the soil properties and the microbial community, we hypothesize that the main determinants of the microbial community may be litter input. When litter decomposition rates are slow, such as in this northern system, five growing seasons may not be sufficient to detect the impact of a changing plant community on the soil microbes.
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Steffan, Shawn Alan. "Biodiversity and fear ecology the cascading effects of species richness and nontrophic interactions /." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Dissertations/Spring2009/s_steffan_041709.pdf.
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Klinka, Karel. "Plant diversity in old-growth and second-growth stands in the coastal rainforests of British Columbia." Forest Sciences Department, University of British Columbia, 1997. http://hdl.handle.net/2429/652.
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One of the human activities impacting biodiversity is the cutting of old-growth forests. In response to the controversy surrounding the cutting of old-growth in the coastal rainforest of BC, the Ministries of the Environment and Forests have produced biodiversity guidelines that are to be applied when manipulating stands in the provincial forest.
This study augments these guidelines by investigating the diversity differences between second-growth and old-growth forests in relation to site quality. We demonstrate how standlevel plant diversity differs between 40-year-old and old-growth stands in the Very Wet Coastal Western Hemlock subzone (CWHvm) on Vancouver Island. This information is intended to provide foresters with an understanding of the effects of age, disturbance and site quality on stand-level plant diversity, thereby allowing for informed professional management decisions.
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Stein, Claudia. "Biodiversity and ecosystem functioning: regional and local determinants of plant diversity in montane grasslands /." Leipzig : UFZ, 2008. http://www.ufz.de/data/ufzdiss_11_2008_9590.pdf.
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Kjellström, Felicia. "Impact of Olive Cultivation on Biodiversity in Messenia, Greece." Thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-107144.
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The biggest threat and cause to loss of biodiversity have been found to be the intensification of agriculture under the 20th century. Messenia is one of the oldest olive cultivation areas in Greece and the landscape is dominated by olive groves characterized by extensive tillage, which causes serious erosion and might be a threat to plant diversity. Organic olive cultivation is an alternative that aims to preserve and support biodiversity. In this study the plant composition in the edge zones of an organic and a conventional olive grove in Messenia were inventoried to be able to investigate if organic cultivation methods enhance plant diversity. Moreover, other factors affecting plant diversity in olive groves and suggestions for precautions in the olive cultivation sector to support biodiversity are discussed. The results show that the organic olive grove hosted 40 % higher species richness, which indicates, as in other similar studies, that the organic olive cultivation methods have a higher capacity to support biodiversity. By restricting tillage and promoting organic olive cultivation, not only biodiversity would be enhanced; this could also prevent further soil erosion and create a more heterogenic agricultural landscape with higher biological and cultural values.
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Muhl, Sara. "The patch-scale distribution pattern of Stipa capensis and its affect on annual plant diversity and growth." Thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/23933.
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Bryant, Jonathan. "The effects of increasing atmospheric nitrogen deposition and carbon dioxide on the growth and physiology of component species of the chalk grassland plant community." Thesis, University of Sussex, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266449.
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Dogan, Hakan Mete. "Understanding And Modeling Plant Biodiversity Of Nallihan (a3-ankara) Forest Ecosystem By Means Of Geographic Information Systems And Remote Sensing." Phd thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/4/1172436/index.pdf.
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In this study, geographic information systems (GIS) and remote sensing (RS)
tools were integrated and used to investigate the plant species diversity of the Nallihan
forest ecosystem. Two distinct indices, Shannon Wiener and Simpson, were employed in
order to express species diversity. The relationships between the indices and pertinent
independent variables (topography, geology, soil, climate, supervised classes, and
Normalized Difference Vegetation Index (NDVI) classes) were investigated to develop
two distinct models for each index. After detecting important components with factor
analysis, two models were developed by using multiple regression statistics. Running the
models, two plant species diversity maps in grid format were produced. The validity of the
models were tested by (1) mapping residuals to predict the locations where the models
work perfectly, and (2) logical interpretations in ecological point of view. Elevation and
climatic factors formed the most important component that are effective on plant species
diversity. Geological formations, soil, land cover and land-use characteristics were also
found influential for both models. Considering the disturbance and potential
evapotranspiration (PET), the model developed for Shannon Wiener index was found out
more suitable comparing the model for Simpson index.
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Boyle, Brad, Nicole Hopkins, Zhenyuan Lu, Garay Juan Antonio Raygoza, Dmitry Mozzherin, Tony Rees, Naim Matasci, et al. "The taxonomic name resolution service: an online tool for automated standardization of plant names." BioMed Central, 2013. http://hdl.handle.net/10150/610265.
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BACKGROUND:The digitization of biodiversity data is leading to the widespread application of taxon names that are superfluous, ambiguous or incorrect, resulting in mismatched records and inflated species numbers. The ultimate consequences of misspelled names and bad taxonomy are erroneous scientific conclusions and faulty policy decisions. The lack of tools for correcting this 'names problem' has become a fundamental obstacle to integrating disparate data sources and advancing the progress of biodiversity science.RESULTS:The TNRS, or Taxonomic Name Resolution Service, is an online application for automated and user-supervised standardization of plant scientific names. The TNRS builds upon and extends existing open-source applications for name parsing and fuzzy matching. Names are standardized against multiple reference taxonomies, including the Missouri Botanical Garden's Tropicos database. Capable of processing thousands of names in a single operation, the TNRS parses and corrects misspelled names and authorities, standardizes variant spellings, and converts nomenclatural synonyms to accepted names. Family names can be included to increase match accuracy and resolve many types of homonyms. Partial matching of higher taxa combined with extraction of annotations, accession numbers and morphospecies allows the TNRS to standardize taxonomy across a broad range of active and legacy datasets.CONCLUSIONS:We show how the TNRS can resolve many forms of taxonomic semantic heterogeneity, correct spelling errors and eliminate spurious names. As a result, the TNRS can aid the integration of disparate biological datasets. Although the TNRS was developed to aid in standardizing plant names, its underlying algorithms and design can be extended to all organisms and nomenclatural codes. The TNRS is accessible via a web interface at http://tnrs.iplantcollaborative.org/ webcite and as a RESTful web service and application programming interface. Source code is available at https://github.com/iPlantCollaborativeOpenSource/TNRS/ webcite.
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Uliczka, Helen. "Forest biodiversity maintenance : instruments and indicators in the policy implementation /." Uppsala : Dept. of Conservation Biology, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/s291.pdf.
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Hatchwell, Paul K. "A national biodiversity audit of conservation and management status of vascular plant flora in Mexico." Thesis, University of Salford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402643.
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Haydu, Kristie. "Mapping Plant Biodiversity Hotspots at the County Scale: A New Tool for Establishing Resource Conservation Strategies." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/749.
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Myers first identified the world’s 25 biodiversity hotspots and pioneered innovative ideas about the usefulness of biodiversity models for establishing long-term resource conservation strategies at global scales. Since Myers, most of the subsequent studies using hotspot science for biodiversity modeling have used large spatial scales like countries, provinces or states, and other biogeoraphic regions. The California Floristic Province continues to be one of the recognized global biodiversity hotspots. Our study site, San Luis Obispo County is within this hotspot and we created a map of plant biodiversity hotspots at the county scale using GIS technology. We wanted to determine the effectiveness and applicability of biodiversity hotspot mapping at this scale with anticipation that the map will serve as a new tool for establishing long-term resource conservation strategies in the County. Our plant biodiversity hotspot map is based on distribution data collected from herbarium specimens of San Luis Obispo County’s rare flora. These data were extracted from the Hoover Herbarium at Cal Poly and manually digitized into GIS. We built a model with GIS to identify, locate, and quantify the resultant hotspots from the data. The overall approach was successful at identifying and quantifying the attributes and geographic extents of plant biodiversity hotspots at the county scale. Our results are highly applicable for establishing local and regional plant conservation priorities at lower resolutions, which is frequently where land acquisition and reserve establishment occurs. We conclude that biodiversity hotspot modeling with GIS is an effective tool that can be applied to many other finer-scale biological inventories for conservation purposes.
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Szöke, Tim. "A hierarchical phytosociology of the Greater Zandvlei area." Bachelor's thesis, University of Cape Town, 2006. http://hdl.handle.net/11427/24963.
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The Zandvlei Nature Reserve is to be expanded to form the Greater Zandvlei Estuary Nature Reserve and will encorporate a much greater area (250 more hectares). The Greater Zandvlei area was classified by means of Zurich Montpellier (Braun Blanquet) procedures. 60 relevés were used to create a hierarchical phytosociology using TWINSPAN and DCA-ordination analyses. 3 major community types were identified, which were then subdivided to reveal 6 community types important to future management: Moist Grassland/Wetland Disturbed Parkland, Dune Asteraceous Fynbos, Thicket/Shrub Mosaic, Rhus-Euclea Dune Thicket and Homogenous Patches. CCA-ordination indicates that the abiotic soil factors sampled (texture composition, pH, carbon content and visible disturbance) explain very little of the variation between the communities (r²=0.002). This phytosociology is provided as a tool for future research in the area, and it is hoped to assist in future management decisions regarding the newly founded GZENR.
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Muhl, Sara. "Long-term salinity trends in Zandvlei estuary and implications for dominant macroalgae." Bachelor's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/25721.
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Zandvlei is a system that has been highly modified by the urban environment of Cape Town. Salinity is a major driver determining the physical environment of estuaries. The macroalgal community of estuaries forms an important part of the ecology of these systems as primary producers. The salinity of this environment is an important parameter determining the composition, abundance and diversity of these communities. Patterns of salinity fluctuations in the long term (1978-2003) and annually are described in order to establish how communities may vary. Zandvlei is in a Mediterranean climate and salinity was found to vary seasonally and monthly with fluctuations in rainfall. Historical records of macroalgae identified in the estuary were summarized and no record of the Polysiphonia sp., now dominant in the estuary, was found. Dominant macroalgae in the estuary were identified and grown under a range of salinities (0, 1, 5, 10, 20, 29 ppt). Dominant macroalgae included Cladophora sp., Polysiphonia sp. and Enteromorpha prolifera. None of these algae survived at O ppt. In 1 ppt E. prolifera survived but growth was retarded, Polysiphonia sp. survived but did not grow and Cladophora sp. grew successfully at this salinity. All three species have different optimum ranges for growth with E. prolifera preferring higher salinities, Cladophora sp. grew similarly across the range from 1 to 29 ppt and Polysiphonia sp. grew most rapidly at 5 ppt. Depending on the salinity range in the estuary different macroalgae will be dominant. This makes the macroalgae community quite resilient to fluctuating salinities. There should therefore always be estuarine macroalgae present in the estuary provided salinity does not drop below 1 ppt for an extended period. If salinities did drop below 1 ppt there could be an increase in freshwater algae.
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Hempson, Gareth. "An alternative hypothesis for explaining anomalies in the fine scale distribution patterns of Colophospermum mopane : Are shrub and tree forms genetically distinct ?" Bachelor's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/26022.
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Abiotic and top down control hypotheses do not adequately explain the fine scale distribution patterns of shrub and tree Colophospermum mopane (Caesalpinioideae). Genetic distinctiveness between growth forms is investigated as an alternative hypothesis. Tree and shrub C. mopane from the riparian and inland savanna zones were sampled at four sites in the northern Kruger National Park. Molecular DNA sequences were obtained for four plastid and one nuclear region, and the inter simple sequence repeat (ISSR) technique used to fingerprint individuals. Very low levels of sequence divergence were observed. The ISSR technique revealed no genetic structure between plants when grouped by growth form or by habitat in an analysis of molecular variance (AMOV A). Soil profile and xylem pressure potential data also did not explain the distribution of growth forms. A principle component analysis and a discriminant analysis of five leaf and branching characters identified a significant difference in the shape of shrub and tree C. mopane leaves. It is concluded that the C. mopane growth forms are not genetically distinct and that their fine scale distributions may be due to top down controls such as large mammals and fire.
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Hempson, Gareth. "Quantifying Acacia defences : understanding the role of hooks, spines and architecture." Bachelor's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/26121.
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The effectiveness of the structural defences of Acacias vary within and between species as a result of differences in thorn type (hooks versus spines) and branching architecture. This study aims to develop methods for quantifying the effectiveness of defences, thereby allowing for comparisons between individuals and localities. Measurements of a range of thorn and branching parameters of eight Acacia species were used to calculate three indices (stripping, biting and branching) describing different components of Acacia structural defences. These were combined to form an overall defence index that was tested against the results of three feeding simulation tests as well as actual animal feeding rates obtained from trials using nyala held in bomas. The stripping, biting and branching indices were shown to provide a good measure of the different components of a structural defence, although the scaling of their contribution to an overall defence index is complicated by variation in the suite of browsers and the resources available at a locality. The indices developed in this study provide a useful tool for assessing the role of large mammal herbivory in different environments when attempting to understand variation in the life history strategies of Acacias.
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Schwarzschild, Arthur C. "Growth Response of Eelgrass (Zostera marina L) to Root-Rhizome and Whole Plant Exposure to Atrazine." W&M ScholarWorks, 1993. https://scholarworks.wm.edu/etd/1539617661.
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Omer, Zahra Saad. "Bacterial-plant associations with special focus on pink-pigmented facultative mehtylotrophic bacteria (PPFMs) /." Uppsala : Dept. of Plant Pathology and Biocontrol Unit, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/a456-ab.html.
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Bigirimana, Joseph. "Urban plant diversity patterns, processes and conservation value in Sub-Saharan Africa: case of Bujumbura in Burundi." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209636.
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This study focuses on the vegetation of the African city of Bujumbura, Burundi. Urban flora is detailed according to the origin of the species (native or introduced), their life form, the use of these species by the local population and their behaviour (invasive or not). The correlation between different natural and anthropogenic environmental factors and the composition of plant communities has been demonstrated through the analysis of vegetation plots. Three types of green areas were studied: spontaneous vegetation on terra firma, wetlands
and domestic gardens.
The main ecological factor correlated to the composition of the spontaneous vegetation of terra firma is the degree of urbanization. From the suburb to the city centre, savannah species typical for the region are replaced by alien invasive species, mostly ruderals. The latter generally have a large distribution, often on several continents. The physiognomy of the vegetation also changes, with hemicryptophytes and phanerophytes in the outskirts and the dominance of therophytes and chamaephytes in the city centre.
In most of wetlands, a large proportion of the plant species are natives, but some wetlands are almost totally invaded by alien species. Soil type is the main environmental factor correlated with
the variability of the vegetation.
The flora of domestic gardens is mainly composed of introduced species used as ornamental, food or medicinal plants. The socio-economical status of the neighbourhood is the main factor correlated with the variability of the garden flora. In high standing neighbourhoods, most species are onamental, with many trees and shrubs. In popular neighbourhoods, the flora is mainly utilitarian (vegetables and fruits), with a significant proportion of native species, and composed mainly of annual species.
A small proportion of the alien species cultivated in gardens has become invasive in the semi-natural vegetation of the city and its surroundings. Many other species cultivated in the gardens could become invasive, based on their ecology and their invasive behaviour in other regions with a climate similar to that of Bujumbura.
Overall, the city of Bujumbura has a diverse flora, with many useful species (vegetables and fruits, traditional medicine, construction of fences and roofs, material for mats and art objects.). The vegetation also hosts wildlife: birds, fishes, hippos, crocodiles etc…
In conclusion, the vegetation of Bujumbura contributes to biodiversity conservation and provides services to the urban population, but the expansion of alien invasive species and the consequent homogenization of the vegetation is a challenge for the future.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Struckhoff, Garrett Cletus Parkin Gene F. "Plant-assisted bioremediation of perchlorate and the effect of plants on redox conditions and biodiversity in low and high organic carbon soil." [Iowa City, Iowa] : University of Iowa, 2009. http://ir.uiowa.edu/etd/441.
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Struckhoff, Garrett Cletus. "Plant-assisted bioremediation of perchlorate and the effect of plants on redox conditions and biodiversity in low and high organic carbon soil." Diss., University of Iowa, 2009. https://ir.uiowa.edu/etd/441.
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Perchlorate is a known inhibitor of the human thyroid gland. Perchlorate is destroyed by ubiquitous perchlorate-reducing bacteria. The bacteria often lack sufficient electron donor. Research was undertaken to evaluate the relationship between plants and perchlorate-reducing bacteria. To what degree can plant-produced electron donors stimulate perchlorate reduction in low organic carbon (LOC) and high organic carbon (HOC) soil? A complication is that plants have been shown to influence redox conditions which may inhibit perchlorate reduction. The removal of perchlorate in a flow-through reactor was monitored with variables of soil organic carbon, hybrid poplar trees, and bioaugmentation. The biodiversity was monitored using denaturing gradient gel electrophoresis.
Low oxidation-reduction potential (ORP) was shown to indicate the capacity for greater perchlorate removal in soil. However, in planted LOC soil systems, evidence suggests that perchlorate reduction may also be possible at higher bulk redox conditions than previously observed. Increased hydraulic retention time was shown to both lower bulk ORP and increase perchlorate removal.
Radiolabeled perchlorate was used to find that in planted systems as much as 11.7% of the influent perchlorate mass was taken up into the tree and 82% of the perchlorate taken up was accumulated in the leaves. The plant contribution to total perchlorate removal in nonbioaugmented LOC soil was 39%, with the balance of the removal being attributed to microbial reduction. In bioaugmented soil the microbial contribution to perchlorate removal was increased.
Just planting poplar trees decreased the diversity of perchlorate reducers in the soil. However, when LOC soil was both planted and bioaugmented, the diversity of perchlorate reducers was not decreased. In HOC soil, the presence of an indigenous population of microorganisms competed with perchlorate reducers. At the increased ORP observed in planted HOC soil, the non-perchlorate-reducing bacteria appear to outcompete the perchlorate reducers and perchlorate removal is decreased.
Engineering implications of this research are that perchlorate remediation in HOC soil does not benefit from planting hybrid poplar trees but that remediation in LOC soil is stimulated by planting and bioaugmentation.
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Beton, Damla. "Effects Of Climate Change On Biodiversity: A Case Study On Four Plant Species Using Distribution Models." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613538/index.pdf.
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Conservation strategies are mainly focused on species existing in an environment shaped by natural and anthropogenic pressures. Yet, evidence shows that climate is changing faster than ever and expected to continue to change in the near future, which can be devastating for plants with restricted ranges.
Turkey harbors many endemic species that might be affected from these changes. However, available data is scarce and biased, complicating the anticipation of future changes. Aim of this study is to improve our understanding of endemic species distributions and forecasting effects of climate change via species distribution modelling (SDM).
The study is based on two Anatolian (Crocus ancyrensis and Crataegus tanacetifolia) and two Ankara (Salvia aytachii and Centaurea tchihatcheffii) endemics. Independent presence and absence data (ranging between 19-68 and 38-61, respectively) for each species was collected through fieldwork in and around the Upper Sakarya Basin in 2008 and 2009.
With the software Maxent, SDMs were performed by using 8 least correlated environmental features and random presence records (of which 25% were used for confusion matrix). SDMs for current distributions of C. ancyrensis, C. tchihatcheffii and C. tanacetifolia were reliable enough for future extrapolations despite errors originating from scale, non-equilibrium status and biotic interactions, respectively. The model for S. aytachii failed due to absence of limiting factor (soil type) in the model.
Future projections of those three species modelled using CCCMA-CGCM2 and HADCM3 climate models indicated three possible responses to climate change: (1) Extinction, especially for habitat specialists(2) Range expansion, especially for generalist species
and (3) Range contradiction, especially for Euro-Siberian mountainous species. Species modelling can be used to understand possible responses of plant species to climate change in Turkey. Modelling techniques should to be improved, however, especially by integrating other parameters such as biotic interactions and through a better understanding of uncertainties.
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Mohamad, Azhar. "Genome organisation, evolution and biodiversity in Musa : application to stress-related gene discovery and plant breeding." Thesis, University of Leicester, 2006. http://hdl.handle.net/2381/29738.
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This thesis shows how anonymous markers are used to assay genetic polymorphisms, and then describes the analysis of major biotic-stress related genomic motifs from diverse Musa accessions, before identifying Bacterial Artificial Chromosome (BAC) clones carrying biotic and abiotic stress-related DN MOTIFS. Microsatellite (SSR) and retroelement-related sequences are abundant and can be exploited as anonymous genetic markers in Musa. SSR primers designed within sequenced BAC clones identified polymorphisms in Musa. LTR-retrotransposon fragments, including Pseudoviridae (Tyl-copia-like) and Metaviridae (Ty3-gypsy-like) families were present as different families in BACs with no correspondence to particular Musa genomes, but are useful for understanding genome evolution. Primers designed from genomic and EST databases were exploited to characterize sequences containing Nucleotide Binding Sites (NBS) and Leucine-Rich Repeat (LRR) motifs (associated with disease resistance genes), and genes associated with tolerance to heat (HSP, 70HSP), salinity (STP) and drought (DRFP) stress. Neither NBS nor LRR sequences are conserved with respect to genome, indicating that R-genes are specific and exist independently. BAC libraries allow tagging of conserved domains of NBS, LRR, retroelement and SSR motifs, giving understanding of the genomic context and control of R-genes. Reliable characterisation of these domains in Musa is possible via PCR-based screening. The thesis gives abroad insight into genome organisation, evolution and diversity of major classes of R-genes, enabling progress towards gene discovery and exploitation for plant breeding.
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Tink, Michael. "The influence of historical and contemporary landscape structure on plant biodiversity : effects on species and genetics." Thesis, University of Brighton, 2017. https://research.brighton.ac.uk/en/studentTheses/992f5f1a-7ca1-48d1-9b82-592a449876bd.
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Biodiversity describes diversity at different levels of biological organisation, including: habitat diversity; species diversity; and genetic diversity. Understanding the processes that contribute to maintaining biodiversity is a primary concern for both ecology and evolutionary biology. To this end, research into the factors influencing the different levels of biodiversity independently are widespread. However, little is understood about the relationship between the different levels. This study investigates the patterns of habitat, species, and genetic diversity in fragmented internationally important calcareous grasslands, and analyses the spatial and temporal factors influencing them. Finally, the relationship between these levels of biodiversity is examined. Within the South Downs National Park study area, substantial change to habitat diversity and landscape structure was measured between the 1930s and 2012. The transition of semi-natural habitat to agricultural land was the predominate change. Loss of habitat between the 1930s and 2012 was found to influence both species richness and species evenness of vegetation in twelve calcareous grassland study sites. By contrast, none of the variables examined explained the variation in species composition between sites. Further analysis, at the genetic level, for two target species showed that the amount of habitat loss was important in explaining the genetic variation in Cirsium acaule, and soil nutrients were important in explaining the variation of Ranunculus bulbosus. In contrast to the predictions of the species genetic diversity correlation theory, no relationship was established between species and genetic diversity. Similarly, no relationships were found between habitat diversity and diversity at the species or genetic level. Although there were similarities in the factors influencing different levels of biodiversity, habitat diversity, species diversity, and genetic diversity appear to be responding independently to the processes acting on them. As such efforts to conserve biodiversity should consider the influence of conservation strategies on biodiversity holistically, and not focus on a single measure.