Ecological and evolutionary factors affecting threatened and endangered species may compromise a population’s ability to persist through time. Here, I determined how plant mating system, pollination biology, pollen source, habitat type, and white-tailed deer (Odocoileus virginianus) herbivory affected the persistence of a rare wetland endemic plant, Polemonium vanbruntiae (Eastern Jacob’s ladder). In contrast to several of the more common species of Polemonium, I found no pollen limitation in populations of P. vanbruntiae. The lack of pollen limitation was best explained by the capacity for P. vanbruntiae to self-fertilize. However, pollinators play an important role as inter- and intra-plant pollen vectors in this system because female reproductive fitness was greatly reduced when pollinators were excluded. These results support the reproductive assurance hypothesis, whereby the ability to self assures fertilization for plants in small populations. A mixed-mating strategy, including the ability for clonal reproduction, may explain the ability for this rare species to persist in small, fragmented populations. However, mixed mating strategies may incur both costs and benefits. The ability to self-fertilize may provide reproductive assurance that when pollinators and/or potential mates are scarce. Yet, selfing is potentially costly when the result is a reduction in offspring quantity and quality. I found that the relative performance of selfed offspring was lower than outcross offspring in terms of germination and offspring vigor. When pollen is received from a distant site, offspring exhibit heterosis with increased vigor in terms of more leaves, larger leaf area and height. Although I was unable to follow offspring survival to flowering, enhanced germination success and more vigorous growth suggest that gene flow among populations may increase plant vigor and enhance genetic variation within small, isolated populations of P. vanbruntiae. For long-lived organisms such as perennial plants, it is often difficult to determine which environmental factors will have the largest effects on long-term population dynamics. I incorporated the effects of habitat type and white-tailed deer herbivory into a population viability model for P. vanbruntiae to determine the effects of both habitat and herbivory on long-term ramet dynamics. Polemonium vanbruntiae ramets in wet meadow habitats are expected to increase at a faster rate than ramets in the forest seep habitats, but P. vanbruntiae is expected to increase over time in both habitat conditions. White-tailed deer preferentially browsed adult ramets, primarily those occurring in forest seep sites. Deer browsing significantly decreased the predicted population growth rate under stochastic conditions, although P. vanbruntiae ramets are expected to increase at a slow rate in the future under herbivore pressure. Herbivory also increased the extinction risk to a detectable level. Deer browsing shifted the potential for younger life histories stages to change future population growth. Instead, survival and stasis of large vegetative ramets became the vital rates having the largest potential impact on future population growth. Thus, active long-term management of deer populations appears necessary for the guaranteed persistence of populations of rare, endemic herbs such as P. vanbruntiae.

<p>Semi-natural grasslands, which are a declining and fragmented habitat in Europe, contain a high biodiversity, and are therefore of interest to conservation. This thesis examines how plant diversity is influenced by the landscape context, and how plant and fungal diversity can be targeted by practical conservation using indicator species and congruence between species groups. Reproduction and recruitment of the dioecious herb <i>Antennaria dioica </i>was also investigated, providing a case study on how fragmentation and habitat degradation may affect grassland plants.</p><p>Grassland size and heterogeneity were of greater importance for plant diversity in semi-natural grassland, than present or historical connectivity to other grasslands, or landscape characteristics. Larger grasslands were more heterogeneous than smaller grasslands, being the likely reason for the species-area relationship.</p><p>A detailed study on <i>A. dioica </i>discovered that sexual reproduction and recruitment may be hampered due to skewed sex-ratios. Sex-ratios were more skewed in small populations, suggesting that dioecious plants are likely to be particularly sensitive to reduced grassland size and fragmentation.</p><p>A study on indicators of plant species richness, used in a recent survey of remaining semi-natural grasslands in Sweden, revealed several problems. A high percentage of all indicator species were missed by the survey, removing an otherwise significant correlation between indicator species and plant species richness. Also, a null model showed that the chosen indicator species did not perform significantly better than species chosen at random from the available species pool, questioning the selection of the indicators in the survey. Diversity patterns of the threatened fungal genus <i>Hygrocybe</i> were not congruent with plant species richness or composition. Plants are thus a poor surrogate group for Hygrocybe fungi, and probably also for other grassland fungi. Implications from this thesis are that conservation of semi-natural grasslands should target several species groups, and that an appropriate scale for plant conservation may be local rather than regional.</p>

Neste estudo, avaliamos a distribuição espacial de recursos florais de Eriotheca gracilipes e suas conseqüências para a atividade de abelhas e florívoros no sucesso reprodutivo desta espécie de Cerrado. A distribuição de flores de Eriotheca gracilipes revelou que a disponibilidade destes recursos variou espacial e temporalmente. No ano em que a floração foi mais expressiva no cerrado, estas variações afetaram de modo distinto as abelhas grandes que visitam as flores de E. gracilipes à procura de néctar e pólen, quando estas abelhas responderam positivamente ao aumento na disponibilidade de flores, tanto na escala do indivíduo, como na escala da vizinhança. Independente da fase sexual das flores de E. gracilipes, a maior parte da variação na produção de energia do néctar é determinada pela variação entre flores e esta variação é determinada pela variação na produção de energia das flores na fase masculina. A maior produção de néctar na fase masculina das flores de Eriotheca gracilipes pode ser resultado de pressões seletivas distintas entre as funções sexuais. A incidência de florivoria em E. gracilipes diferiu entre os agentes e as fisionomias. As maiores taxas de sobrevivência das estruturas reprodutivas no cerrado e a correlação positiva entre o número de botões produzidos e o número de frutos formados nesta fisionomia reforçam a hipótese de que variações espaciais nas interações entre species, sejam elas mutualistas ou antagonistas, poderiam afetar diferentemente a reprodução sexuada de E. gracilipes, de acordo com as espécies antagonistas envolvidas. / In this study we evaluated the spatial distribution of Eriotheca gracilipes floral resources and its consequences for the bee foraging behavior, florivores and the reproductive output of this Cerrado species. Spatial and temporal variations were detected for Eriotheca gracilipes flower availability. At the cerrado physiognomy in 2005, this variation affected differently the large bees that visit E. gracilipes flowers, looking for pollen and nectar. Under this situation, we detected positive pollinator responses to the floral display of focal plants and also to its neighborhood. The greatest variation in energy production was explained by variation among flowers in male phase. The higher nectar production in male flowers indicated that distinct selective pressures might be occurring at each sexual function. The incidence of florivores reduced E. gracilipes flower availability and their action were different between agents and physionomies. Trigona spinipes had a major impact on buds and flowers of E. gracilipes at the campo cerrado. Our data indicate that spatial and temporal variation between plant-pollinator and plant-florivores occured even under low and almost homogeneous flower availability, affecting differently E. gracilipes reproductive success.

Semi-natural grasslands, which are a declining and fragmented habitat in Europe, contain a high biodiversity, and are therefore of interest to conservation. This thesis examines how plant diversity is influenced by the landscape context, and how plant and fungal diversity can be targeted by practical conservation using indicator species and congruence between species groups. Reproduction and recruitment of the dioecious herb Antennaria dioica was also investigated, providing a case study on how fragmentation and habitat degradation may affect grassland plants. Grassland size and heterogeneity were of greater importance for plant diversity in semi-natural grassland, than present or historical connectivity to other grasslands, or landscape characteristics. Larger grasslands were more heterogeneous than smaller grasslands, being the likely reason for the species-area relationship. A detailed study on A. dioica discovered that sexual reproduction and recruitment may be hampered due to skewed sex-ratios. Sex-ratios were more skewed in small populations, suggesting that dioecious plants are likely to be particularly sensitive to reduced grassland size and fragmentation. A study on indicators of plant species richness, used in a recent survey of remaining semi-natural grasslands in Sweden, revealed several problems. A high percentage of all indicator species were missed by the survey, removing an otherwise significant correlation between indicator species and plant species richness. Also, a null model showed that the chosen indicator species did not perform significantly better than species chosen at random from the available species pool, questioning the selection of the indicators in the survey. Diversity patterns of the threatened fungal genus Hygrocybe were not congruent with plant species richness or composition. Plants are thus a poor surrogate group for Hygrocybe fungi, and probably also for other grassland fungi. Implications from this thesis are that conservation of semi-natural grasslands should target several species groups, and that an appropriate scale for plant conservation may be local rather than regional.

Understanding the functional relationship between characters and components of fitness is a central goal of evolutionary biology. The studies in this thesis examined the ecological causes and evolutionary consequences underlying differences in fitness among individuals of Lobelia cardinalis. Flowering plants experience selection from many sources, which may enhance or oppose selection by pollinators. In the second chapter of this thesis, the role of pollinators and herbivores in shaping selection on floral characters was investigated. Floral traits experienced pollinator-mediated selection and weak selection by weevil larvae and slugs. Because pollinators also forage according to local density of flowers, in the fourth chapter I explored how local density of individual plants and flowers influences fitness of individual plants. Plants at dense sites produced more seeds, consistent with pollinator preference for denser patches. Individual female-phase flowers produced more seeds as the density of surrounding male-phase flowers increased and female-phase flowers decreased. This study highlights how plant phenotype and local density influence pollination and subsequent plant fitness. In L. cardinalis rosette formation (a life-history character) partly shapes the distribution of plants, and may influence plant survival and fitness. In the fifth chapter, I explored how variation in allocation to clonal reproduction among plants (ramets) and genets influenced survival and fitness. Plants that produced more and larger rosettes realized higher survival independent of the phenotype of the parental. Plants that produced one rosette in 2009 produced more seeds in 2010 than plants that produced more than one rosette. This pattern was reversed in the following time period; plants that produced more rosettes in 2010 produced more seeds in 2011. The relative importance of pollinators versus other selective agents in shaping floral traits, as well as the intensity of competition among individual plants and flowers likely depend on the extent to which reproduction is pollen limited. In the third chapter, I explored how pollen limitation affected selection on floral traits via female fitness and found a weak relationship. Although this seems to contradict intuition, several reasons may limit the influence of pollen limitation on selection.

Today traditionally managed wooded hay meadows only exist in small fractions of their former distributions. Because of the fragmentation and degeneration of hay meadows and the fact that pollinating insect diversity and abundance also are declining, pollination services in these habitats requires attention. To examine the pollination services in traditionally managed hay meadows I collected Ranunculus acris (Buttercup) in 20 meadows of varying quality on Gotland and evaluated the mean seed set and mean number of produced seeds per plant. I also collected Filipendula vulgaris (Dropwort) in 18 meadows and evaluated the mean seed set to be able to compare the pollination success of the insect pollinated R. acris with the wind pollinated F. vulgaris. A range of habitat variables were collected in the meadows and in older surveys to examine their relative impact on seed set. I found significantly higher seed set for R. acris in the meadows with higher habitat quality, than in meadows with lower quality. In contrast seed set in F. vulgaris was not related to habitat quality. The population density also seemed to play an important role in fertilization rate for R. acris, through increased seed set in high density areas, while plant height was positively correlated with number of produced seeds. For F. vulgaris seed set was positively correlated with moss cover, and number of seeds per plant was positively correlated with population density. These results suggest that reproductive success among insect pollinated plants are more sensitive to habitat degeneration than among wind pollinated plants. The status of pollination services in traditionally managed wooded hay meadows should be evaluated further.

Orientador: Elza Guimarães / Resumo: As plantas normalmente apresentam um limite máximo de frutificação que é determinado pela disponibilidade de recursos maternos, no entanto, o sucesso reprodutivo feminino de determinadas espécies é ainda menor que o potencial intrínseco à planta-mãe. Nesse caso, fatores extrínsecos à planta, como a limitação de pólen, decorrentes das interações ecológicas estabelecidas com mutualistas e antagonistas da comunidade, podem interferir e impactar negativamente a reprodução. Considerando que a investigação simultânea de fatores intrínsecos e extrínsecos à planta pode ajudar a estabelecer o papel de cada um deles sobre a baixa produção de frutos em angiospermas, neste trabalho nós avaliamos experimentalmente a contribuição relativa da limitação de recursos maternos e da limitação de pólen sobre o sucesso reprodutivo de Jacaranda caroba (Bignoniaceae), uma espécie selecionada como modelo por ser zoófila, predominantemente xenógama e apresentar baixa frutificação natural. Assim, testamos as seguintes hipóteses: (1) o número total de frutos é menor que o número total de flores produzidas pela planta na ausência de limitação de pólen; (2) a frutificação natural é ainda inferior à capacidade de formação de frutos das plantas devido à limitação de pólen; (3) a baixa frequência de visitas do polinizador ou a transferência de grãos de pólen inadequados resulta em limitação quantitativa e qualitativa, respectivamente; (4) abelhas que roubam ou pilham recursos atuam como antagonistas 10 afe... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Neste estudo, avaliamos a distribuição espacial de recursos florais de Eriotheca gracilipes e suas conseqüências para a atividade de abelhas e florívoros no sucesso reprodutivo desta espécie de Cerrado. A distribuição de flores de Eriotheca gracilipes revelou que a disponibilidade destes recursos variou espacial e temporalmente. No ano em que a floração foi mais expressiva no cerrado, estas variações afetaram de modo distinto as abelhas grandes que visitam as flores de E. gracilipes à procura de néctar e pólen, quando estas abelhas responderam positivamente ao aumento na disponibilidade de flores, tanto na escala do indivíduo, como na escala da vizinhança. Independente da fase sexual das flores de E. gracilipes, a maior parte da variação na produção de energia do néctar é determinada pela variação entre flores e esta variação é determinada pela variação na produção de energia das flores na fase masculina. A maior produção de néctar na fase masculina das flores de Eriotheca gracilipes pode ser resultado de pressões seletivas distintas entre as funções sexuais. A incidência de florivoria em E. gracilipes diferiu entre os agentes e as fisionomias. As maiores taxas de sobrevivência das estruturas reprodutivas no cerrado e a correlação positiva entre o número de botões produzidos e o número de frutos formados nesta fisionomia reforçam a hipótese de que variações espaciais nas interações entre species, sejam elas mutualistas ou antagonistas, poderiam afetar diferentemente a reprodução sexuada de E. gracilipes, de acordo com as espécies antagonistas envolvidas. / In this study we evaluated the spatial distribution of Eriotheca gracilipes floral resources and its consequences for the bee foraging behavior, florivores and the reproductive output of this Cerrado species. Spatial and temporal variations were detected for Eriotheca gracilipes flower availability. At the cerrado physiognomy in 2005, this variation affected differently the large bees that visit E. gracilipes flowers, looking for pollen and nectar. Under this situation, we detected positive pollinator responses to the floral display of focal plants and also to its neighborhood. The greatest variation in energy production was explained by variation among flowers in male phase. The higher nectar production in male flowers indicated that distinct selective pressures might be occurring at each sexual function. The incidence of florivores reduced E. gracilipes flower availability and their action were different between agents and physionomies. Trigona spinipes had a major impact on buds and flowers of E. gracilipes at the campo cerrado. Our data indicate that spatial and temporal variation between plant-pollinator and plant-florivores occured even under low and almost homogeneous flower availability, affecting differently E. gracilipes reproductive success.

Orientador: Marlies Sazima / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-16T08:56:09Z (GMT). No. of bitstreams: 1 Brito_ViniciusLourencoGarcia_M.pdf: 8743517 bytes, checksum: efdc732f7b02ccea2c628acf24677361 (MD5) Previous issue date: 2010 / Resumo: As montanhas apresentam alta diversidade e diferentes condições ambientais ao longo de curtas distâncias. Assim, as montanhas são ideais para estudos ecológicos e evolutivos que podem somar valores e aprimorar projetos de conservação. Em altitudes elevadas as condições ambientais podem reduzir a quantidade de polinizadores, principalmente de abelhas. Desta forma, em espécies estritamente melitófilas, características como a fenologia, o sistema reprodutivo, o fluxo de pólen e a estrutura genética das populações pode variar ao longo do gradiente, uma vez que a transferência de grãos de pólen aos estigmas co-específicos também varia ao longo do gradiente. No caso de áreas de elevada altitude, a transferência de pólen é limitada (limitação de pólen), reduzindo as possibilidades de polinização cruzada. O presente estudo tem por objetivo obter informações sobre a biologia da polinização, reprodução e genética de duas populações de Tibouchina pulchra (Melastomataceae) ocorrentes em duas áreas de gradiente altitudinal: Núcleo Santa Virgínia (NSV) e Núcleo de Desenvolvimento Picinguaba (NDP) do Parque Estadual da Serra do Mar. Foram feitas observações mensais para definir padrões e estratégias de floração, registrar dados sobre a biologia floral e reprodutiva, além de verificar a riqueza e abundância dos polinizadores e caracterizar as interações dessa espécie com as abelhas visitantes. Material genético de 44 indivíduos do NSV e 45 indivíduos do NDP foram coletados para o desenvolvimento e caracterização de 12 loco microssatélites polimórficos e estes foram utilizados para fazer análises de agrupamento, ordenação bayesiana e medidas de diversidade genética nas duas populações. Os aspectos da biologia reprodutiva são diferentes entre as duas áreas: na área elevada a florada é mais intensa, a produção de pólen é menor, há limitação na transferência de pólen, mas a fertilização de sementes provindas de polinização cruzada manual é maior. Na outra área são produzidos mais frutos e há maior riqueza e abundância de polinizadores. Ocorre diferenciação genética entre as populações, mas com uma interface de contato entre elas, além de menor diversidade genética na população da área elevada. Estes resultados indicam que a ausência de polinizadores na região de altitude elevada está associada a diferentes estratégias na biologia floral e reprodutiva para balancear a limitação de pólen. Além disso, diferentes dinâmicas de fluxo gênico mediado pelo pólen nas duas populações e as características de distribuição e reprodução podem influenciar a estrutura e a diversidade genética de Tibouchina pulchra ao longo da Serra do Mar / Abstract: Mountains have high diversity and many environmental conditions at short distances. Hence, they are an ideal place to develop ecological and evolutionary studies that can improve conservation projects. At high altitudes, the environmental conditions reduce pollinator abundance, mainly bees. Therefore, traits such as phenology, breeding system and genetic structure of plant populations pollinated by bees could vary in an altitudinal gradient, because pollen grain transference to co-specific flowers varies also. At high altitudes pollen transference is limited (pollen limitation) reducing cross-pollination. The main goal of the present study was to obtain information about pollination biology, breeding system and genetic structure of two populations of Tibouchina pulchra (Melastomataceae) that occur in two different areas of an altitudinal gradient: Núcleo Santa Virgínia (NSV) and Núcleo de Desenvolvimento Picinguaba (NDP) of Parque Estadual da Serra do Mar. Field work was done monthly to describe the flowering patterns and strategies, record floral and reproductive biology, verify pollinator diversity and characterize the interactions among this plant species and bee visitors. Genetic material was collected from 44 Tibouchina pulchra individuals of NSV and 45 individuals of NDP to developed and characterize 12 microsatellite polymorphic loci, which were used to analyze population's genetics by different methods. At the higher area the plants have greater flowering intensity, the flowers produce less pollen grains and the stigmas receive less pollen, but set more seeds after manual cross pollination than individuals at the lower area, where pollinator diversity is higher and plants produce more fruits. There is genetic differentiation, but also an interface contact between the two populations. The population at higher altitude has less genetic diversity than the one at lower altitude. The lack of pollinators at the higher area is associated with different floral and reproductive strategies to compensate pollen limitation. Moreover the genetic structure and diversity respond to different dynamics of pollen flow and the patterns of distribution and reproduction of Tibouchina pulchra at the altitudinal gradient of Serra do Mar / Mestrado / Biologia Vegetal / Mestre em Biologia Vegetal

Habitat fragmentation is one of the main threats to semi-natural grasslands all over Europe, causing reductions in both numbers of populations and numbers of individuals withinpopulations. Small isolated populations are particularly vulnerable to fluctuations that reducespopulation size and could lead to loss of genetic variation due to inbreeding depression, orfixation of harmful alleles due to genetic drift. The aim of this study was to investigate if thecritically endangered eyebright Euphrasia stricta var. suecica experiences pollen limitation,inbreeding depression and heterosis or outbreeding depression. Low pollen limitation waspredicted as well as low inbreeding depression due to high selfing rate. Outbreedingdepression or heterosis was expected based on previous studies indicating strong geneticdifferentiation among populations. This study was conducted in two traditionally managedmeadows in the central part of Gotland, Sweden, using supplemental hand-pollinations andcontrolled crosses. Individuals were collected when the flowering period was over and seedswere counted and weighed. There were no signs of either pollen limitation, inbreedingdepression, heterosis or outbreeding depression in any of the two wooded hay meadows. Thedegree of autonomous selfing was high, indicating that E. stricta var. suecica is not dependenton pollinators for seed production. A significant difference between the meadows was foundin proportion of viable seeds. As there were no signs of local adaptation, individuals could betranslocated between the two studied populations or seed sowings could be used to increasepopulation size. However, before such conservation efforts are undertaken, it is important toconduct further studies that investigate several populations including more life-stages.