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Testing Subspecies Limits in <i>Monardella Villosa</i>Crow, Taylor McLaughlin 01 June 2013 (has links) (PDF)
Several subspecies of Monardella villosa (California Coyote Mint) have been distinguished on the basis of leaf thickness, shape, and trichome characteristics, yet many intermediates are known. We investigated morphological differences in natural populations of two subspecies (M. v. subsp. villosa and M. v. subsp. franciscana) in the Scott Creek watershed, north of Davenport, in Santa Cruz County, CA. Monardella villosa subsp. franciscana grows in coastal scrub in gulches and ocean terraces whereas subsp. villosa grows at more protected inland sites. Morphological difference between subspecies may be adaptations to these different habitats. I grew plants in a common garden at Cal Poly, San Luis Obispo to determine if the morphological differences were genetically based. I also conducted a reciprocal transplant of the two subspecies between inland and coastal populations to determine if they are locally adapted.
The morphological differences (leaf hair density and length as well as leaf base angle) between subspecies were maintained in the common garden, yet no patterns of local adaptation were observed in germination or survival of the subspecies in reciprocal transplants in the first year. However, Monardella is a perennial plant and fitness differences may exist in later life stages that I have not yet measured.
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EVIDENCE FOR LOCAL ADAPTATION IN BIRDSROHWER, VANYA 28 September 2010 (has links)
Phenotypic traits that vary geographically within species are commonly assumed to represent local adaptations to different environments. In order for local adaptation to evolve by natural selection, three conditions must be met: (1) traits must vary geographically, (2) local variants of traits must provide a fitness advantage (increased survival or reproductive success) within the local environment, and (3) local variants of traits must be heritable. In chapter two, we review evidence for local adaptation in birds. Geographic variation among populations is nearly ubiquitous, yet experimental tests of the fitness advantages of local trait variants are rare among populations of birds, presumably because of the difficulties in transporting individuals between populations. Thirty-seven studies have tested the heritability of among population variation in traits. Thirty-three of the 37 studies found some degree of heritability of variation among populations, consistent with traits diverging in response to natural selection. In chapter three, we experimentally test the fitness consequences of divergent nest morphologies of Yellow Warblers (Dendroica petechia) using reciprocal nest transplant experiments between a temperate and subarctic site in Canada. Yellow Warblers breeding at our subarctic site build larger nests constructed with more insulative materials than Yellow Warblers breeding at our temperate site, and these differences are the result of different nest building behaviours. Temperate nests transplanted to subarctic sites experienced significantly colder temperatures, and tended to suffer higher egg and nestling mortality due to climatic conditions (cold temperatures), than locally transplanted subarctic nests. Adult females breeding in subarctic sites that received temperate nests changed their incubation behaviours by taking shorter recesses than females who received locally transplanted subarctic nests. In contrast, subarctic nests transplanted to our temperate site showed no changes in nest temperature, fledgling success, or parental behaviour during incubation. We suggest that divergent selective pressures acting on Yellow Warblers in subarctic and temperate environments results in different nest building behaviours. Cold temperatures in our subarctic site likely favour increased investment in larger, insulative nests, whereas warmer temperatures at our temperate sites likely favour reduced investment in nest building, and consequently smaller nests. / Thesis (Master, Biology) -- Queen's University, 2010-09-28 13:16:38.686
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Translocation of Acropora cervicornis Across Geographic Regions: Investigating Species Recovery and RestorationBliss, Bradley Cody 01 January 2015 (has links)
This thesis is the first known study to relocate Acropora cervicornis across multiple regions of the Florida Reef Tract. Since 2006, A. cervicornis has been listed as a threatened coral species under the U.S. Endangered Species Act. In response, restoration efforts utilizing coral nursery methods have been implemented throughout the Caribbean. The primary objective of this research was to determine the response of A. cervicornis colonies to being relocated between two coral nurseries separated by approximately 150km along the Florida Reef Tract. To accomplish this, a reciprocal transport was conducted between coral fragments with known genotypes from Broward County and Monroe County, Florida. A subset of coral ramets (fragments of a single genotype) was removed from the nursery of origin and relocated to the opposing coral nursery, while the remaining ramets stayed in their original nursery to serve as controls. Following transplant, both relocated and non-relocated corals were monitored for 14 months and survivorship, growth rates, branching frequency, and coral condition data were collected. In addition, tissue samples were collected twice during the monitoring period to determine zooxanthellae densities. Reaction norms were used to predict the responses of each measured variable for each genotype in response to being relocated. Relocated coral colonies from both nurseries exhibited equal or greater survivorship than the non-relocated corals from their original nursery. Growth rates, branching frequency, and zooxanthellae densities were highest in the corals that were previously in or relocated to Broward County. Within each nursery, relocated and non-relocated corals were not significantly different in any of the measured parameters. Throughout the study period, there were no signs of disease, bleaching, or predation on any of the corals. These findings demonstrate that A. cervicornis colonies can be successfully relocated across regions of the Florida Reef Tract suggesting that colonies throughout the FRT may be used for collaborative restoration efforts. Reaction norm analysis indicated phenotypically plastic responses in each growth parameter with some instances of genotype-by-environment interactions. Finally, these results suggest the need for additional research to investigate regional differences in A. cervicornis populations for proper management and restoration approaches.
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Lokální adaptace přírodních populací Arabidopsis arenosa k hadci. / Local adaptation of natural population of Arabidopsis arenosa to serpentine soilLamotte, Timothée January 2021 (has links)
Arabidopsis arenosa represents a promising model for studying the mechanisms underlying the adaptation to serpentine soil. Genetic basis of serpentine adaptation is still poorly known and A. arenosa possesses many advantages as a tool to complete that knowledge. The first step of this study was to reveal the presence of a local adaptation to serpentine soil in a population of A. arenosa. To do so, I used the data from a reciprocal transplant experiment realized between a Czech pair of serpentine - non-serpentine populations and I explored the phenotypes associated with the adaptation. Subsequently, I produced the F2 hybrids coming from crosses between serpentine - non-serpentine parents and I studied the expression of fitness traits in F2 plants growing in serpentine in order to estimate the number of loci underlying the adaptation which I compared with other studies. I confirmed the presence of a local adaptation, with the population of serpentine origin performing better than the non-serpentine population in the serpentine substrate of origin, associated with accumulation of heavy metals in the leaves. Analyses of the soil composition revealed differences in heavy metals and nutrients contents, Ca/Mg ratio and pH between the two localities. Those results fitted with the function of the candidate...
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Reciprocal Transplant and Machine Learning Study of Oak Mistletoe on Three Host Oak Species in Santa Margarita, CaliforniaAbelli-Amen, Ella 01 June 2021 (has links) (PDF)
At Santa Margarita Ranch, California, oak mistletoe (Phoradendron villosum) parasitizes valley oak and blue oak but cannot be found growing on coast live oak despite its abundance and ability to parasitize coast live oak in other areas. It seems as though this species of mistletoe is specializing on certain host oak trees, but the mechanisms of this specialization are unknown. In order to investigate this pattern, we utilized a type of machine learning in GIS called supervised classification as well as a reciprocal transplant study in the field. The three species of oak trees were classified with 87% accuracy using drone imagery and 95% accuracy using open source NAIP imagery. This classification technique could be applied to the whole state of California as long as ground truth points for each species were collected. This could be extremely useful for large scale forest management projects and ecological questions. Unfortunately, the classifier was unsuccessful at distinguishing mistletoe from host and so the number of mistletoe on each host could not be quantified using this technique. The reciprocal transplant study involved collecting mistletoe fruit from individuals growing on each of the three hosts and experimentally applying them back onto all three hosts. This allowed us to test whether there are host races of mistletoe that specialize at growing on certain hosts. We found that seeds from each host origin germinated equally well regardless of where they were dispersed, and seeds survived best on coast live oak, regardless of where they originated from. Based on these results, there must be some mechanism, other than host races, that explains the lack of mistletoe on coast live oaks at Santa Margarita Ranch. Future projects should investigate whether evidence for host races can be found at a later stage of seedling development and the roll of bird dispersers in creating the pattern.
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Diversité et adaptation des arbres forestiers : analyse de gradients altitudinaux et de transplantations croisées chez le sapin pectiné / Diversity and adaptation of forest trees : analysis of silver fir altitudinal gradients and reciprocal transplant experimentsLatreille, Anne 19 January 2017 (has links)
Les populations répondent aux variations de l'environnement par une adaptation dans un premier temps plastique puis, à plus long terme, génétique. Cette faculté à évoluer est aujourd'hui confrontée à un changement climatique à la fois très rapide et de grande ampleur. L'étude de 15 provenances de sapin pectiné (Abies alba Mill.) réparties sur trois gradients altitudinaux (~ 900 à 1600 m) nous a permis d'évaluer par des approches de dendroécologie et de génétique quantitative leurs caractéristiques phénotypiques et génétiques ainsi que leur potentiel d’acclimatation et d’adaptation. La croissance radiale de 129 arbres adultes répartis le long des gradients a été analysée. Six traits adaptatifs liés à la croissance, la phénologie et la survie ont été mesurés sur 57 descendances maternelles issues de ces provenances et installées en transplantations réciproques dans neuf jardins communs répartis sur les gradients. Les résultats montrent que (i) la diversité phénotypique des populations est principalement due à l’environnement (i.e. plasticité phénotypique), (ii) l’ensemble des traits mesurés sur les semis sont sous contrôle génétique, (iii) les populations étudiées ne semblent pas avoir été soumises à des sélections différenciées (iv) le sapin est très sensible à la sécheresse estivale, d’autant plus si elle se répète d’une année sur l’autre. L’ensemble de ces résultats suggère que les populations étudiées présentent de bonnes capacités d’adaptation mais qu’à plus ou moins court terme, le sapin pectiné est menacé d’extinction à basse altitude ou en marge sud de son aire de répartition. / Natural populations respond to environmental variations firstly by plastic behavior, and, in the longer term, by genetic adaptation. Currently, the rapid and widespread climate change is challenging this ability to evolve. We studied 15 provenances of silver fir (Abies alba Mill.) distributed along three altitudinal gradients (~900 to 1600 m). We evaluated their phenotypic and genetic characteristics and their acclimation and adaptation potential, using dendroecological and quantitative genetic approaches. The radial growth of 129 adult trees distributed along the gradients were analyzed. Six adaptive traits related to growth, phenology and survival were measured on 57 maternal families collected from these provenances and planted following a reciprocal transplant experimental design in nine common gardens distributed along the gradients. The results show that (i) the phenotypic diversity of populations is mainly due to the environment (i.e. phenotypic plasticity), (ii) all the traits measured on seedlings are under genetic control, (iii) the studied populations do not appear to have been subjected to differentiated selections, (iv) silver fir is very sensitive to summer drought, especially when it is repeated over years. All these results suggest that studied populations have great adaptive capacities but that in the short term, silver fir is threatened by extinction on the southern or low elevation margins of its range.
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Host-Associated Differentiation in an Insect CommunityDickey, Aaron 2010 December 1900 (has links)
Host-Associated Differentiation (HAD) is the formation of genetically divergent hostassociated
lineages maintained by ecological isolation. HAD is potentially an important
route to ecological speciation in parasites including many insects. While HAD case
studies are accumulating, there is a dearth of negative results in the literature making it
difficult to know how common the phenomenon really is or whether there are specific
traits of parasites which promote HAD. To address these two problems, studies are
needed which both publish negative results (i.e., parasites not showing HAD) and test
for HAD in multiple parasite species on the same pair of host species (i.e., control for
host plant effects).
In this study, HAD was tested in three species of herbivorous insects and one parasitoid
species on the same two host tree species: pecan and water hickory. The insects were
selected based on the presence or absence of two traits, parthenogenesis and endophagy.
A test for HAD was considered “positive” when population substructure was explained
by host-association. To test for the presence of HAD, insects were sampled sympatrically to eliminate geographical isolation as a confounding factor, sampling was
replicated spatially to assure that HAD persisted, and multiple loci were sampled from
each individual. Genetic data was analyzed using cluster analyses. HAD was found in
both pecan leaf phylloxera and yellow pecan aphid but not in pecan bud moth or in the
parasitoid of the yellow pecan aphid, Aphelinus perpallidus. Interestingly, both taxa
showing HAD are parthenogenetic and both taxa not showing HAD reproduce sexually.
Species showing HAD were tested for the presence of a pre-mating reproductive
isolating mechanism (RIM) which could be maintaining HAD despite the potential for
gene flow. Selection against migrants to the alternative host was tested in yellow pecan
aphid using a no-choice fitness experiment. The overall contribution of this RIM to total
isolation was positive and ranged from 0.614 to 0.850. The RIM of “habitat preference”
was tested in pecan leaf phylloxera using a dual-choice preference experiment. In this
species, preference was only detected for phylloxera originating from water hickory
suggesting that host discrimination ability may be a less important factor promoting
differentiation in phylloxera.
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La provenance des boutures influence-t-elle le rendement et les taux de phytoextraction des saules dans un sol contaminé?Beauchamp, Sonia 03 1900 (has links)
La survie et la croissance des plantes sont essentielles afin d’assurer l’efficacité des protocoles de phytoremédiation et la décontamination des friches contaminées. La survie des saules et leur adaptation aux contaminants dépendent de la nature et de la concentration des contaminants. L’objectif de l’étude est d’identifier les cultivars ayant les meilleurs rendements, mais aussi de déterminer si la provenance des boutures (milieu contaminé ou milieu non contaminé) pourrait influencer la survie, la croissance et la phytoextraction (Cd, Cr, Cu, Ni, Pb, Zn) des saules. Nous avons comparé ces différents paramètres pour des boutures de dix cultivars de saules dans un milieu industriel fortement contaminé par les composés organiques et dans un milieu non-contaminé. Les variations dans la réponse des cultivars selon la provenance des boutures (milieu contaminé ou milieu non-contaminé) ont aussi été analysées dans chacun des sites d’étude. Selon nos résultats, le cultivar ˈ5005ˈ (Salix alba) est très productif en milieu extrêmement contaminé. Le cultivar ˈS25ˈ (Salix eriocephala) est aussi un choix très intéressant en phytoremédiation, puisqu’il produit près de deux fois plus de biomasse racinaire comparativement aux autres cultivars. La provenance des boutures n’a pas d’impact significatif sur la survie, la croissance et la phytoextraction pour la majorité des cultivars sauf pour le cultivar ‘Millbrook’, où les individus provenant du milieu contaminé ont produit significativement plus de biomasse aérienne lorsqu’ils poussaient en sol contaminé comparativement aux individus qui n’ont jamais été en contact avec les contaminants. Ces résultats pourraient aider à planifier des protocoles de phytoremédiation plus efficaces, en sélectionnant les cultivars de saule les plus adéquats et en élaborant l’échantillonnage des boutures utilisées dans les sites appropriés. / Plant survival and growth are essential parameters to monitor the effectiveness of phytoremediation protocols and the eventual decontamination of brownfields. The ability of different willow cultivars to survive and adapt to contaminants in polluted soils depends on the nature and concentration of the contaminants. The objective of the study was to identify the cultivars with the highest yields, but also to determine whether the origin of the cuttings (contaminated site or not) might influence survival, growth and phytoextraction of willow cultivars. We compared survival, growth and phytoextraction (Cd, Cr, Cu, Ni, Pb, Zn) of cuttings of ten willow cultivars in a highly organic-contaminated industrial environment and in an uncontaminated soil. Variations in the response of the cultivars according to the origin of the cuttings were also analyzed for each sites. According to our results, cultivar ˈ5005ˈ (Salix alba) was very productive in an extremely contaminated environment. Cultivar ˈS25ˈ (Salix eriocephala) was also a relevant choice, as it produced nearly twice more root biomass compare to other cultivars. The origin of the cuttings did not have significant influence on survival, growth and phytoextraction for almost all cultivar except the ˈMillbrookˈ cultivar: individuals originating from the contaminated environment produced significantly more aboveground biomass when growing in the contaminated environment compared to individuals who had never been in contact with contaminants. These results could help build more effective phytoremediation protocols in highly contaminated environments by selecting adequate willow cultivars and sampling cuttings in an appropriate environment.
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Biologie de la conservation du corail rouge, Corallium rubrum (Linnaeus, 1758) : impact du changement global sur l'évolution des populations infralittorales en Méditerranée Nord-Occidentale / Conservation biology of the red coral, Corallium rubrum (Linnaeus, 1758) : impacts of the global change on the evolution of the shallow populations in the North Western Mediterranean SeaLedoux, Jean-Baptiste 26 October 2010 (has links)
Les pressions anthropiques agissent en synergie du gène à l’écosystème, des régions polaires aux régions tropicales et induisent une érosion biologique telle, qu'elle est qualifiée de sixième extinction de masse.Ce constat pose la question de l’évolution de la biodiversité face aux changements environnementaux en cours. C’est dans ce contexte que s’inscrit ce travail de thèse focalisé sur les populations de surface (5 -60 m) de corail rouge, Corallium rubrum (Linnaeus, 1758), en Méditerranée Nord-Occidentale.Le corail rouge (Octocorallia, Coralliidae) est une espèce sessile à phase larvaire caractérisée par sa longévité importante, sa dynamique de population lente et son rôle structurant au sein des communautés de substrats durs de Méditerranée. Soumis à une importante pression de récolte, Corallium rubruma récemment subi deux évènements de mortalité massive concordant avec des anomalies thermiques positives, potentiellement liées au réchauffement climatique. La combinaison de ces deux pressions environnementales est donc susceptible d’affecter fortement l’évolution des populations de surface de cette espèce. Basé sur une approche intégrant génétique des populations et écologie de terrain, ce travail a pour objectif principal d’étudier les processus microévolutifs en jeu chez le corail rouge, de l’inter- à l’intra- populationel, afin de contribuer à l'amélioration de nos connaissances sur la biologie de cette espèce dans le contexte environnemental actuel.Ce travail de thèse élargit le champ de connaissances relatif à l’écologie de Corallium rubrum et fournit un ensemble d’outils et de données pour sa conservation face aux perturbations environnementales en cours.Il contribue, par la même occasion, à une avancée significative dans la compréhension de la biologie des organismes marins sessiles à phase larvaire.Il illustre notamment la pertinence d'approches mises place à des échelles spatiales réduites, pour répondre à des questions fondamentales sur l’évolution de ces organismes, souvent clés au sein de communautés sous pression / Anthropic pressures act synergistically from gene to ecosystems and from polar to tropical regions, inducing a strong biological loss, which is considered by many as the sixth mass extinction. The evolution of biodiversity facing the ongoing global change is thus an open question.The present study is focused on the shallow populations (5 - 60 m) of Corallium rubrum (Octocorallia,Coralliidae) in the North Western Mediterranean Sea. The red coral is a sessile and long-lived species with a larval phase, a slow population dynamics and an important structuring role in the Mediterranean hard substrates communities. This species faces a strong harvesting pressure, and recently underwent two massmortality events linked to positive thermal anomalies putatively due to ongoing climate change. These two pressures may have deep implications on the evolution of the shallow populations of this species. Using population genetics and field ecology, the main objective of this study was to define microevolutionary processes acting between and within red coral populations, to enhance our knowledge on the biology of this species facing the environmental changes. This work extends our knowledge concerning the ecology of Corallium rubrum, and provides new toolsand data for its conservation in the context of the ongoing global change. Moreover, this work improves our understanding in the biology of sessile marine organisms with a larval phase, illustrating for example the relevance of approaches conducted at fine geographical scales to address questions regarding the evolution of these organisms.
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