Tesis sobre el tema "Altitudinal variation"

Global declines and disappearances of amphibians from high altitude, pristine habitats have been reported in recent years. To date the cause of many of these declines and/or disappearances has not been identified. Although it is well documented that life history characteristics of temperate amphibians are influenced by altitude (due to systematic variation of temperature with altitude), little work has been carried out on the effects of altitude on Australian anurans. This lack of ecological data is a major impediment to identifying the causal factors responsible for amphibian declines. Due to differences in life history characteristics, high altitude populations may be less resilient than their lowland counterparts and subsequently may be more vulnerable to extinction. Consequently, the main aim of this study was to determine whether altitude influenced life history characteristics and ultimately population resilience of anurans in the southeast Queensland region. Six anuran species; Litoria chloris, L. lesueuri, L. pearsoniana (Anura: Hylidae), Mixophyes fasciolatus, M. fleayi and M. iteratus (Anura: Myobatrachidae) were studied over three field seasons (1997-1999) in 18 sites of varying altitude (100-950m) in the southeast Queensland region. The life history characteristics examined were: activity and breeding season length, fecundity and egg size, number of clutches produced per season, tadpole growth and development rates, longevity, age at maturity, reproductive life span, average lifetime fecundity, survival and recapture rates. The data were collected using a combination of field-based surveys (body sizes, clutch sizes, and survival and recapture rates), museum specimen dissections (clutch and egg sizes), reciprocal transplant field experiments (tadpole growth and development rates) and skeletochronology (longevity, age at maturity, reproductive lifespan and average lifetime fecundity). On average, high altitude populations of all species had shorter breeding and activity seasons than low altitude populations (up to 10 weeks less in some cases). The magnitude of the difference in breeding season length varied among years depending on the average temperature and rainfall for the year; i.e. differences appeared greater in warmer and wetter years. Within a population males had longer breeding and activity seasons than females. Although breeding season length varied with altitude, the number of nights that individuals were active within the breeding season did not vary; i.e. low altitude populations were not active for more nights despite having a longer breeding season. This result was attributed to the absence of a relationship between individual activity and environmental variables (air temperature, rainfall, etc.) in many of the populations. Generally, intraspecific clutch size did not vary significantly with altitude. This result was due to the absence of a significant relationship between female body size and altitude (as clutch size is proportional to female body size). Egg size also did not vary with altitude however, suggesting egg size may be canalized (i.e. fixed) in these species. Results also suggest that females of these species only produce one clutch of eggs per season. Interspecific differences in reproductive characteristics largely reflected differences in reproductive mode, larval habitat and female body size. Altitude negatively influenced growth and development rates in L. chloris and development rates in L. pearsoniana. Tadpoles raised at high altitudes were also generally larger at each Gosner Development Stage in both species. The results of the reciprocal transplant experiments suggested that most of the variation in growth and development rates was due to environmental factors (water temperature) rather than genetic or maternal factors. Altitude or genetic factors did not significantly affect tadpole survival in either species. The results suggest that tadpoles occurring at high altitudes take longer to reach metamorphosis and do so at a larger size than their lowland counterparts. With the exception of L. lesueuri, skeletochronology was suitable for age estimation in the study species. Altitude had a significant effect on the age at maturity or longevity in some of the species, however there were trends toward older individuals and older ages at maturity in high altitude populations for the remaining species. Females were generally older than males for all species and in the case of longer-lived species (i.e. Mixophyes spp.) also tended to be older when breeding for the first time. The large overlap of body sizes of individuals of different ages demonstrates that body size is a poor indicator of age in these species. This is the first study to estimate average lifetime fecundity for more than one amphibian species and/or population. The results suggest that the absence of significant altitudinal variation in the average lifetime fecundity of different populations is due to tradeoffs made by females (current reproduction vs. survival). There was no significant altitudinal variation in annual survival and recapture rates in any of the species, and generally there was no difference in the survival and recapture rates of males and females in each population. Within a year, monthly survival and recapture rates were more variable at low than high altitudes and this was attributed to the longer breeding season of low altitude populations. The results did not support previous studies that suggested there was a size bias in survival and recapture rates. The shorter breeding seasons, slower growth and development rates, older age at maturity and greater longevity found in the high altitude study populations will result in increased generation time in those populations. In turn, increased generation time can cause high altitude populations to be less resilient (i.e. population takes longer to return to equilibrium after a disturbance away from equilibrium) (Pimm et al. 1988, Pimm 1991) and ultimately more vulnerable or prone to extinction or decline. The majority of unexplained global amphibian declines have occurred at high altitudes in tropical and subtropical areas. These latitudinal patterns may be explained by the narrow range of environmental tolerances exhibited by tropical organisms resulting in mountains being effectively “higher” in the tropics. Consequently, high altitude tropical species are likely to be even more vulnerable than temperate species occurring at similar altitudes. Further work on the effects of geographic variation, especially interactions between altitude and latitude are needed to evaluate the hypotheses for the causes of these declines and disappearances.

Dans cette thèse, j'examine la dynamique de l'investissement parental et la fitness chez la mésange bleue eurasienne (Cyanistes caeruleus) dans les Pyrénées françaises, et j'évalue les différences potentielles dues à un gradient altitudinal qui crée une variation de "dureté" environnementale. J'ai utilisé de données observationnelles et expérimentales, recueillies de plus de 500 nids de mésanges bleues. Les conditions de reproduction sont " plus dures " en cas de températures plus froides et d'une élévation croissante. J'ai trouvé que l'altitude croissante conduit à une diminution du succès de l'éclosion. Néanmoins, la taille des couvées et la mortalité des couvées sont comparables à travers le gradient. Je suggère que les décisions initiales en matière de procréation, telles que le moment et la quantité de progéniture, déterminent fortement le succès d'une tentative de reproduction. Ces résultats ont des implications pour notre compréhension du succès de reproduction
In this thesis, I examine parental investment and fitness in the Eurasian blue tit (Cyanistes caeruleus) in the French Pyrenees and assess potential differences due to an altitudinal gradient that creates variation in environmental "harshness". I used observational and experimental data, collected from over 500 blue tit nests. Breeding conditions are "harsher" due to colder temperatures with increasing elevation. I found that increasing altitude leads to decreased hatching success. Nevertheless, clutch size and brood mortality is comparable across the gradient. I suggest that initial reproductive decisions such as timing and amount of offspring produced heavily shape the success of a reproductive attempt. These results have implications for understanding reproductive success

Altitudinal gradients offer attractive opportunities for studies of population differentiation in response to environmental heterogeneity. In this thesis, I examined population differentiation along altitudinal gradients by combining common-garden experiments with field studies and experiments in alpine, subalpine and boreal populations of the perennial herb Solidago virgaurea. More specifically, I determined whether leaf physiology in terms of nitrogen concentration and resorption, flowering phenology, flower production and reproductive effort vary along altitudinal gradients. Nitrogen concentration in green leaves were higher in alpine than in subalpine and boreal populations. These differences persisted when plants were grown from seeds in a common-garden experiment at two sites, suggesting that the differences have a genetic component. There was mixed support for a trade-off between maximized carbon gain through the maintenance of high nitrogen concentration, and minimized nitrogen loss through high resorption. In their natural habitats alpine populations began flowering later than subalpine populations, but this difference was reversed when plants were grown in a common environment. This suggests that genetic differences among populations counteract environmental effects and reduce phenotypic variation in flowering time among populations. Flowering time thus shows countergradient genetic variation in S. virgaurea. In a common-garden experiment, boreal populations produced more flowers and had a higher reproductive effort than subalpine and alpine populations indicating habitat-specific genetic differences in reproductive allocation. In a field study, which included three populations, seed set was close to zero in the alpine population, intermediate in the subalpine population, and high in the boreal population. Experimental flower removal showed that seed production was associated with a considerable cost in terms of reduced flowering propensity the following year, but did not support the hypothesis that a large floral display is important for pollination success.

Les deux sous-espèces annuelles de téosinte qui sont les plus proches parents sauvages du maïs sont d’excellents systèmes pour étudier l’adaptation locale car leur distribution couvre un large éventail de conditions environnementales. Zea mays ssp. parviglumis est distribuée dans un habitat chaud et mésique en dessous de 1800 m d’altitude, tandis que Zea mays ssp. mexicana prospère dans des conditions sèches et fraîches à des altitudes plus élevées. Nous avons combiné des approches d’écologie inverse et de génétique association afin d’identifier les déterminants de l'adaptation locale chez ces téosintes. A partir de données de séquençage haut débit (HTS) de six populations comprenant des populations de basses et hautes altitudes, une étude précédente a identifié un sous-ensemble de 171 polymorphismes nucléotidiques (SNP candidats) présentant des signaux de sélection. Nous avons utilisé ces SNP candidats pour tester l'association entre la variation génotypique et phénotypique de 18 caractères. Notre panel d’association était constitué de 1663 plantes provenant de graines de 11 populations échantillonnées le long de deux gradients d’altitude. Il a été évalué deux années consécutives dans deux jardins communs. Nous avons contrôlé sa structure neutre en utilisant 18 marqueurs microsatellites. La variation phénotypique a révélé l’existence d'un syndrome altitudinal composé de dix caractères. Nous avons ainsi observé une augmentation de la précocité de floraison, une diminution de la production de talles et de la densité en stomates des feuilles ainsi qu’une augmentation de la taille, de la longueur et du poids des grains avec l’élévation croissante du site de collecte des populations. Ce syndrome a évolué malgré des flux de gènes détectables entre populations. Nous avons montré que le pourcentage de SNP candidats associés aux différents caractères dépend de la prise en compte de la structure neutre soit en cinq groupes génétiques (71,7%), soit en onze populations (11,5%), indiquant une stratification complexe. Nous avons testé les corrélations entre les variables environnementales et les fréquences alléliques des SNP candidats sur 28 populations. Nous avons trouvé un enrichissement à la fois pour les SNP présentant des associations phénotypiques et les SNP présentant des corrélations environnementales dans trois larges inversions chromosomiques, confirmant leur rôle dans l'adaptation locale. Pour explorer la contribution de la variation structurale à l'évolution adaptative, nous nous sommes concentrés sur le contenu en éléments transposables (ET) des six populations séquencées (HTS). Ces éléments constituent environ 85% du génome du maïs et contribuent à sa variabilité fonctionnelle. Nous avons effectué la première description populationnelle des ET chez les téosintes pour deux catégories d'insertions, celles présentes et celles absentes du génome de référence du maïs. Nous avons ensuite recherché des polymorphismes liés aux ET présentant des fréquences alléliques contrastées entre populations de basse et de haute altitude. Nous avons identifié un sous-ensemble d'insertions candidates. Enfin, nous avons génotypé, dans un panel d'association, des insertions d’ET connues pour avoir contribué à l'évolution phénotypique du maïs. Contrairement à ce qui a été observé chez le maïs, certaines de ces insertions n'ont montré aucun effet phénotypique chez les téosintes, ce qui suggère que leur effet dépend du fond génétique. Notre étude apporte de nouvelles connaissances sur l’adaptation altitudinale chez les plantes. Elle ouvre la discussion sur les défis soulevés par l'utilisation (1) d'outils de génomique des populations pour identifier la variation adaptative, (2) de populations naturelles en génétique d’association, et (1) de ressources génétiques sauvages pour l'amélioration des espèces cultivées
Annual teosintes, the closest wild relatives of maize, are ideal systems to study local adaptation because their distribution spans a wide range of environmental conditions. Zea mays ssp. parviglumis is distributed in warm and mesic conditions below 1800 m, while Zea mays ssp. mexicana thrives in dry and cool conditions at higher altitudes. We combined reverse ecology and association mapping to mine the determinants of local adaptation in annual teosintes. Based on high throughput sequencing (HTS) data from six populations encompassing lowland and highland populations growing along two elevation gradients, a previous study has identified candidate regions displaying signals of selection. Within those regions a subset of 171 candidate single nucleotide polymorphisms (SNPs) was selected to test their association to phenotypic variation at 18 traits. Our association panel encompassed 1663 plants from seeds collected from eleven populations sampled along the elevation gradients. We benefit from phenotypic characterization of all the plants in two common gardens located at mid-altitude for two years. In addition, we controlled for neutral structure of the association panel using 18 microsatellite markers. Phenotypic variation revealed the components of an altitudinal “syndrome” constituted of ten traits evolving under spatially-varying selection. Plants flowered earlier, produced less tillers, displayed lower stomata density and carried larger, longer and heavier grains with increasing elevation of population collection site. This syndrome evolved in spite of detectable gene flow among populations. The percentage of candidate SNPs associated with traits largely depended on whether we corrected for five genetic groups (71.7%) or eleven populations (11.5%), thereby indicating a complex stratification in our association panel. We analyzed correlations between environmental variables and allele frequencies of candidate SNPs on a larger set of 28 populations. We found enrichment for SNPs displaying phenotypic associations and environmental correlations in three Mb-scale chromosomal inversions, confirming the role of these inversions in local adaptation. To further explore the contribution of structural variation to adaptive evolution, we focused on transposable element (TE) content of the HTS populations. TEs constitute ~85% of the maize genome and contribute to its functional variability via gene inactivation and modulation of gene expression. We performed the first population-level description of TEs in teosintes for two categories of insertions, those present and those absent from the maize reference genome. We next searched for TE polymorphisms with contrasted allele frequencies between lowland and highland populations. We pinpointed a subset of adaptive candidate insertions. Finally, we genotyped in our association panel TE insertions known to have contributed to maize phenotypic evolution. In contrast to what was found in maize, some of these insertions displayed no measurable phenotypic effects in teosintes, suggesting that their effect depends on the genetic background. Altogether our study brings new insights into plant altitudinal adaptation. It opens discussions on the challenges raised by the use (1) of population genomic tools to discover adaptive variation, (2) of natural populations in association mapping, and (1) of wild genetic resources in crop breeding

Juniperus seravschanica is a keystone species within the northern mountains of Oman. The species appears to be declining in the area, particularly at lower altitudes, with little regeneration being recorded. Alterations in temperature and moisture availability due to climate change could be main responsible for this decline. The main aim of this research is to identify causes of decline and suggest viable conservation strategies that may have wider application for tree conservation in this region. Surveys indicate considerable foliar dieback of trees at lower altitudes (< 2500 m) with healthy trees limited to cooler (high altitude) or high moisture sites (wadis and depressions). A lack of juvenile trees indicates inadequate recruitment and highlights conservation concerns. Trees growing at low altitude had low growth rates compared to mid-altitude trees. Trees at low altitude produce fewer seeds and these have a lower proportion of viable, embryo intact seed (9%) with a low germination capacity. In controlled conditions, reducing irrigation below optimum reduced growth, even under optimal temperature. In field studies, seeds and young trees, 2 and 5-year-old, were planted at selected altitudes, Low (2220 m), Mid (2300 m) and High (2560 m); the planted trees were maintained under differential irrigation regimes. Planting young trees were more successful than seed sowing when re-establishing plants in the wild. Age of transplant was important with 5-year-old trees showing greater survival (> 97%) than younger stock. Younger stock only succeeded when planted at high altitude or provided with regular artificial irrigation at low altitude. The availability of high soil moisture was important in maintaining tree viability at low altitude; however, in some locations heat stress too may be limiting plant viability and growth. Practical conservation that includes selecting genotypes with greater drought/heat tolerance and augmenting natural habitat with more mature nursery-grown trees is strongly recommended to avoid further loss of this species.

Un enjeu majeur de la génétique évolutive est de comprendre comment l'adaptation locale se développe en population naturelle, et comment les différentes forces évolutives y contribuent. Les études expérimentales d'adaptation locale utilisent couramment les gradients altitudinaux présentant une variation spatiale marquée des conditions environnementales. Dans ces conditions, on s'attend à ce que la différentiation génétique pour les caractères (traditionnellement mesurée par QST) et pour les gènes déterminant ces caractères (traditionnellement mesurée par FSTq) le long du gradient soit gouvernée de façon prédominante par la sélection et les flux de gènes, et peu influencée en revanche par la dérive génétique et la mutation. En particulier, des études théoriques ont montré un découplage entre QST et FST lorsque que les flux de gènes sont forts et/ou que la sélection est récente. Dans cette étude, nous avons testé cette hypothèse en combinant une approche de génomique expérimentale et des simulations dans des populations naturelles de hêtre commun (F. sylvatica) séparées de ~trois kilomètres et soumis à des environnements contrastés.Pour l'approche expérimentale, nous avons échantillonné 4 populations sur deux gradients altitudinaux sur le Mont Ventoux (avec une population à haute altitude et une à basse altitude sur chaque gradient). Cinquante huit gènes potentiellement impliqué dans la réponse aux stress abiotiques et dans le débourrement ont été séquencés sur un total de quatre-vingt seize individus, révélant 581 SNPs (Single Nucleotide Polymorphisms). Différentes approches ont été utilisées pour identifier les SNP outlier, présentant une différentiation plus forte qu'attendu sous un modèle neutre sans sélection. Le nombre de SNPs outlier identifié comme étant sous sélection s'est révélé être grandement dépendant de la méthode utilisé. La méthode fréquentiste a détecté de nombreux outliers alors que l'approche bayésienne n'a pu permettre de détecter des SNPs sous sélection. Par ailleurs, nous avons utilisé un modèle mécaniste individu-centré pour simuler les patrons de diversité phénotypique et génétique attendus le long du gradient pour la phénologie du débourrement végétatif, un caractère généralement adaptatif dans la réponse aux variations de température. Les résultats des simulations confirment que la différentiation génétique observée pour le caractère (QST) est généralement plus forte que celle observée au gène (FSTq), et que cette différentiation génétique au trait intervient dès la première génération. Toutefois, les tests d'outlier conduits sur le le modèle simulé ont révélé que plus de 95% des SNPs outlier sont des faux positifs. Comme dans l'approche expérimentale, l'approche Bayésienne ne s'est pas révélé suffisamment fiable pour détecter des QTLs dans des populations spatialement proche et génétiquement faiblement différentiée. Néanmoins une approche multi-locus basée sur un estimateur peu utilisé en génétique (le Zg) a révélé la forte corrélation inter-populations inter-gènes des QTLs confirmant les attendus théoriques. Toutefois, cette approche ne permet pas de détecter précisément les QTLs sans connaissance a priori sur les QTLs. En conclusion, les travaux de cette thèse mettent en évidence la rapidité des changements génétique qui interviennent en moins de 5 générations pendant la modification du climat, et la difficulté de détecter les gènes codant pour des traits complexes
A major challenge in population genetics is to understand the local adaptation process in natural population and so to disentangle the various evolution forces contributing to local adaptation. The experimental studies on local adaption generally resort to altitudinal gradients that are characterized by strong environmental changes across short spatial scales. Under such condition, the genetic differentiation of the functional trait (measured by the Qst) as well as the genes coding for trait (measured by Fstq) are expected to be mainly driven by selection and gene flow. Genetic drift and mutation are expected to have minor effect. Theoretic studies showed a decoupling between Qst and Fst under strong gene flow and / or recent selection. In this study, I tested this hypothesis by combining experimental and modelling genomic approach in natural population of Fagus sylvatica separated by ~3 kilometres and under contrasted environments.Sampling was conducted in south-eastern France, a region known to have been recently colonised by F.sylvatica. Four naturally-originated populations were sampled at both high and low elevations along two altitudinal gradients. Populations along the altitudinal gradients are expected to be subjected to contrasting climatic conditions. Fifty eight candidate genes were chosen from a databank of 35,000 ESTs according to their putative functional roles in response to drought, cold stress and leaf phenology and sequenced for 96 individuals from four populations that revealed 581 SNPs. Classical tests of departure of site frequency spectra from expectation and outlier detection tests that accounted for the complex demographic history of the populations were used. In contrast with the mono-locus tests, an approach for detecting selection at the multi-locus scale have been tested.The results from experimental approaches were highly contrasted according the method highlighting the limits of those method for population loosely differentiated and spatially close. The modelling approach confirmed the results from the experimental data but revealed that up to 95% of the SNPs detected as outliers were false positive. The multi-locus approach revealed that the markers coding for the trait are differentially correlated compared to the neutral SNPs. But this approach failed to detect accurately the markers coding for the trait if no a priori knowledge is known about them. The modelling approach revealed that genetic changes may occur across very few generation. But while this genetic adaptation is measurable at the trait level, the available method for detecting genetic adaptation at the molecular level appeared to be greatly inaccurate. However, the multi-locus approach provided much more promise for understanding the genetic basis of local adaptation from standing genetic variation of forest trees in response to climate change

Photoperiodism is the ability of plants and animals to utilize day length or night length to mitigate seasonal exigencies. The circadian clock allows organisms to organize daily demands. Both process are set by light, and for more than 80 years a functional relationship has been pursued. Previous experiments have revealed, through phenotypic expression, that the daily circadian clock and seasonal photoperiodic timer have evolved independently, yet molecular evidence is lacking. Herein, we use the mosquito, Wyeomyia smithii, to understand the relationship between the photoperiodic response, diapause, and the daily circadian clock. We measured variation in the formal properties of the core circadian clock over a latitudinal and altitudinal gradient which we compare to the critical photoperiod, a measure of diapause, over the same geographic gradient. We found that there is no correlation with any of the formal properties of the core circadian clock and critical photoperiod, indicating independent evolution.

Tropical mountain forests contribute greatly to carbon sequestration and reduction of carbon levels in the atmosphere. In order to achieve the “Reducing Emission from forest deforestation and degradation” (REDD +) objectives, reliable information on carbon sequestration of all forest management areas is required. So, this study aims to determine the amount of above ground carbon bound in trees and how carbon sequestration capacity of trees varies with altitudinal change in the Magamba Nature Forest Reserve. A random stratified coordinate by elevation method was used, measuring approximately 2636 tree of 5<diameter at breast height (DBH) distributed across 29 plots with a total area of 2.03ha. The effect of altitude was tested using ANOVA and Pearson correlation test. The results show that there is a significant (p<0.05) positive correlation between aboveground carbon sequestered and elevation, and that there was significant difference (p<0.02) in the amount of aboveground carbon stored between low elevation (147.5 tones ha-1) mid elevation (244.86 tonnes ha-1) and high elevation (245.4 tones ha-1). The lower amount of carbon at low elevation may be due to anthropogenic activities including logging and fuel production, since it is easier to reach lower altitude than higher altitude forest zone. To improve carbon sequestration capacity of tropical Mountain protected forests, participatory protective measure at lower elevation zones are of importance. These should even be included in management plans, detailing the involvement of adjacent community.

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
Over the past decades, several authors have tried to explain the altitudinal distribution patterns and the factors that influence the distribution of species over the elevation gradients. In general, studies show that the richness distribution curve has the shape of a "hump", with intermediate altitudes with higher rates of diversity. Few are those who relate the Melastomataceae with elevation gradient and none addresses the family distribution in Brazil and, consequently, in the Atlantic Forest. The present study had two main objectives: (a) increase the knowledge of the taxonomic diversity of Melastomataceae in the study areas, providing an identification key for the genera, descriptions and evaluating the richness and peculiarities of the taxa, as well as the conservation status (Chapter I); and (b) to analyze the distribution pattern of the diversity of Melastomataceae along the altitudinal variation of a wooded stretch of Serra dos ?rg?os, in the mountainous region of the state of Rio de Janeiro (Chapter II). A floristic survey was done in contiguous protected areas, belonging to Central Fluminense Conservation Units Mosaic: Guapia?? Ecological Reserve (REGUA), Tr?s Picos State Park (PETP) and Serra dos ?rg?os National Park (PARNASO). Periodic collections in the study areas were made using methods of fixed installments and traversal, traversing up primary and secondary trails. In 11 altitudinal allotments distributed between 0-2000 m, were performed a 290 m transect per allotment, following the level curve, where 15 plots of 10 x 10 m were placed, totaling 165 plots placed and 1,65 ha sampled. Moreover, fields located above altitude of 2,100 m were also exploited for a better sampling of the species. The collected material was herborized and identified in laboratory using morphological analysis of vegetative and reproductive parts, subsequently deposited in the RBR Herbarium, with duplicates in RB. Species richness of Melastomataceae raised for the studied area is represented by 152 species belonging to 22 genera. Eight species are cited as vulnerable on the list of endangered species for the city of Rio de Janeiro, one species (Bertolonia leuzeana (Bonpl.) Cogn.) is considered Endangered on the Red Book of Brazil?s Flora and 22 endemic species of Rio de Janeiro are with some degree of threat, by the evaluation of the National Center for Conservation of Flora-CNCFlora. In all altitudinal installments Melastomataceae species were collected, with the highest richness being registered in the 1000m altitudinal installment (57 spp.). The species' altitudinal distribution curve presented a pattern shaped like a ?hump?. REGUA, PETP and PARNASO are located in a region with the largest forest remnants preserved from state of Rio de Janeiro and, because they are legally protected, they have high biological diversity under custody. Despite that in all altitudinal installments Melastomataceae species were collected, it is possible that with increased sampling effort in areas not yet visited or little explored, the number of species of Melastomataceae cited for localities may increase as well as the registration of new species and/or occurrences
Ao longo das ?ltimas d?cadas, v?rios autores t?m procurado explicar os padr?es de distribui??o altitudinal e os fatores que influenciam na distribui??o das esp?cies ao longo dos gradientes de eleva??o. Em geral, os estudos apontam que a curva de distribui??o da riqueza possui o formato de ?corcova?, com as altitudes intermedi?rias apresentando os maiores valores de diversidade. Poucos s?o os que relacionam as Melastomataceae com gradiente de eleva??o e nenhum aborda a distribui??o da fam?lia no Brasil e, consequentemente, na Floresta Atl?ntica. O presente estudo teve dois objetivos principais: (a) ampliar o conhecimento sobre a diversidade taxon?mica das Melastomataceae na ?rea de estudo, fornecendo uma chave de identifica??o para os g?neros, descri??es e avaliando a riqueza e peculiaridades dos t?xons, bem como o estado de conserva??o das esp?cies (Cap?tulo I); e (b) analisar o padr?o de distribui??o da diversidade das Melastomataceae ao longo da varia??o altitudinal de um trecho florestal da Serra dos ?rg?os, na Regi?o Serrana do estado do Rio de Janeiro (Cap?tulo II). Realizou-se o levantamento flor?stico em Unidades de Conserva??o cont?guas, pertencentes ao Mosaico de Unidades de Conserva??o Central Fluminense: Reserva Ecol?gica de Guapia?? (REGUA), Parque Estadual dos Tr?s Picos (PETP) e Parque Nacional da Serra dos ?rg?os (PARNASO). Realizaram-se coletas de campo peri?dicas na ?rea de estudo, por m?todos de parcelas fixas e do caminhamento, percorrendo-se trilhas prim?rias e secund?rias. Em 11 cotas altitudinais, distribu?das entre 0-2000 m de altitude, efetuou-se uma transec??o de 290 m por cota, acompanhando-se a curva de n?vel, onde foram alocadas 15 parcelas de 10 x 10 m, totalizando 165 parcelas alocadas e 1,65 ha amostrados. Al?m disso, os Campos de Altitude localizados acima de 2100 m tamb?m foram explorados, para uma melhor amostragem das esp?cies. O material coletado foi herborizado e identificado em laborat?rio atrav?s de an?lise morfol?gica das partes vegetativas e reprodutivas, sendo posteriormente depositado no Herb?rio RBR, com duplicata no RB. A riqueza de esp?cies de Melastomataceae levantada para a ?rea de estudo est? representada por 152 esp?cies pertencentes a 22 g?neros. Oito esp?cies s?o citadas como vulner?vel na lista das esp?cies amea?adas de extin??o para o munic?pio do Rio de Janeiro, uma esp?cie (Bertolonia leuzeana (Bonpl.) Cogn.) ? citada como Em Perigo, no Livro Vermelho da Flora do Brasil e 22 esp?cies end?micas do Rio de Janeiro encontram-se com algum grau de amea?a, pela avalia??o do Centro Nacional de Conserva??o da Flora - CNCFlora. Em todas as cotas altitudinais foram coletadas esp?cies de Melastomataceae, sendo a maior riqueza registrada na cota 1000 m altitude (57 spp). A curva de distribui??o altitudinal das esp?cies apresentou o padr?o em forma de "corcova". A REGUA, o PETP e o PARNASO est?o localizados numa regi?o que apresenta os maiores remanescentes florestais conservados do estado fluminense e, por serem legalmente protegidos, tem sob a guarda elevada diversidade biol?gica. Apesar de em todas as cotas altitudinais terem sido coletadas esp?cies de Melastomataceae, ? poss?vel que com o aumento do esfor?o amostral em ?reas ainda n?o visitadas, de dif?cil acesso e/ou pouco exploradas, o n?mero de esp?cies seja ampliado, bem como o registro de novas esp?cies e/ou ocorr?ncias.

Orientador: Vera Nisaka Solferini
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-22T01:41:48Z (GMT). No. of bitstreams: 1 Ramos_RafaelFlora_M.pdf: 2299855 bytes, checksum: 943dfb31cd7db5f4dcc0508ca7f17c91 (MD5) Previous issue date: 2013
Resumo: Euterpe edulis é uma palmeira tropical ameaçada de extinção que no passado era abundante na Mata Atlântica, desde a planície costeira até 1.000 metros acima do nível do mar. O objetivo deste estudo foi avaliar a diversidade e a estrutura genética em populações naturais de E. edulis distribuídas em diferentes altitudes dentro de um contínuo florestal. O estudo foi conduzido em uma área de proteção ambiental da Serra do Mar, no litoral norte do estado de São Paulo, onde foram amostrados 300 adultos em seis localidades, denominadas subpopulações. Cada indivíduo foi genotipado com sete locos microssatélite. O número total de alelos foi alto (140) e o número médio de alelos não variou entre as subpopulações. A heterozigosidade total esperada foi de 0,867, variando entre 0,782 e 0,859 entre subpopulações. O índice de fixação foi baixo para todas as subpopulações, concordando com o sistema de reprodução cruzada da espécie. A estruturação espacial genética foi ausente ou muito baixa nas subpopulações analisadas separadamente ou agrupadas. A estrutura genética foi alta (?' = 0,26) considerando a distância máxima de 32 km entre as subpopulações amostradas. Foram definidos quatro grupos genéticos mais prováveis de acordo com o teste de atribuição dos indivíduos, e cinco grupos de acordo com a AMOVA (Análise de Variância Molecular). O teste de Mantel parcial correlacionou à estrutura genética entre pares de subpopulações com a distância geográfica (r = 0,8; p < 0,05) e ainda com a diferença altitudinal excluído o efeito da distância geográfica (r = 0,5; p < 0,05). Se estas diferenças são causadas pelo fluxo gênico reduzido ou por adaptações locais ainda precisa ser testado em estudos futuros. Este padrão de diferenciação genética em distâncias reduzidas é inesperado dentro de um contínuo florestal, destacando a importância de abordagens em pequena escala para a compreensão das dinâmicas complexas nos sistemas tropicais
Abstract: Euterpe edulis is an endangered tropical palm, once abundant throughout the Atlantic Forest from the coastal plain up to 1000 meters above sea level. The main purpose of this study was to evaluate the genetic diversity and structure in natural populations of E. edulis distributed in different altitudes within a continuous forest. The study was conducted in a protected area of Serra do Mar, at the north coast of São Paulo State, where we sampled 300 adults from six locations. Each individual was genotyped with seven microsatellite loci. The total allele number was high (140) and the mean allele number did not vary between samples. The total expected heterozygosity was 0.867, ranging from 0.782 to 0.859 among samples. The inbreeding coefficient was low in all samples, in accordance with the outcrossing breeding system. The spatial genetic structure was absent or weak at populations analyzed individually or grouped. The genetic structure was high (?' = 0.26) considering that the maximum distance of 32 km between samples. Four most likely genetic groups were defined according to the assignment test, and five groups according to AMOVA (Analysis of Molecular Variance). A partial Mantel test correlated the pairwise genetic structure with the geographical distance (r = 0.8; p < 0.05) and also with the pairwise altitudinal differences without the effect of the geographic distances (r = 0.5; p < 0.05). Whether those differences are mainly due to reduced gene flow or to local adaptation remains to be tested in future studies. This pattern of genetic differentiation at short distances is unexpected within a continuous rainforest, highlighting the importance of small scale approaches to understanding the complex dynamics of tropical systems
Mestrado
Ecologia
Mestre em Ecologia

This thesis studies the potential impacts of lapse rate changes on the altitudinal thermal resource gradient in Northern England and hence of climate change on upland climate. The extreme marginality of the Pennine uplands in terms of climatic potential for plant growth is explained by reference to the maritime climate. Because the ground-based temperature lapse rate controls the altitudinal thermal resource gradient, the variation of daily temperature lapse rates by season and airflow is described, using 22 stations ranging from 8 to 847 metres above sea-level. Multiple regression models developed for each airflow in each month successfully describe surface temperature variation in most cases. Such models are used as a basis upon which to describe altitudinal variations in growing season parameters such as accumulated temperatures and frost frequency, for the present climate. Airflow scenarios, based on the regression models, describe the effects of changes in relative frequencies of airflow patterns. The altitudinal gradient in, and absolute values of, growing season parameters depend strongly on relative frequencies of Atlantic westerlies and more blocked conditions. Assuming the annual l000 dºC (degree-day) isotherm to represent the altitudinal limit to agricultural cultivation, individual annual elevations between 1801 and 1990 vary by over 300 metres. Extreme sensitivity to the circulatory pattern is also illustrated. Effects of temperature variability within airflows are at least as strong as those of mean conditions in many cases. The use of General Circulation Model output (UKHI 2 times C0(_2)) leads to strong changes in climatic potential. For example, few areas retain an annual temperature accumulation below 1000 dºC. Changes in frost parameters are also marked. Other climatic and non-climatic factors would have to be considered to predict land-use change. Preliminary analysis suggests that changes in other climatic elements (e.g. windiness or precipitation) will complement the effects of a temperature increase.

Diversos estudos apontam uma forte influência do ambiente terrestre sobre os corpos dágua nele inseridos. No caso de riachos de cabeceira esta relação não se resume a variáveis químicas e físicas, mas também está ligada diretamente ao que chamamos de metabolismo do riacho, regulando o aporte direto de nutrientes em forma de folhiço e material particulado e a produtividade interna, através de incidência de luz. Estes são fatores que estão intrinsecamente ligados a manutenção deste metabolismo e por conseqüência da biodiversidade que existe nestes riachos. Este estudo, através da técnica isotópica do \'dela\'13C e \'delta\'15N e índices ecológicos (riqueza, abundância, diversidade, EPT e EPTC) comparou riachos de Mata Atlântica inseridos em ambientes com diferentes características. Primeiramente com relação à altitude, foram comparados riachos inseridos em matriz de Floresta Ombrófila Densa de Terras Baixas (5 a 50 m), sopé da Serra do Mar e de Floresta Ombrófila Densa Montana (500 a 1.200 m), topo da serra. E em um segundo momento, riachos em diferentes usos do solo, inseridos em matriz de floresta, eucalipto e pastagem. Foram encontradas diferenças não só relacionadas aos índices ecológicos, mas principalmente com relação as variáveis isotópicas, que apontaram mudanças nos padrões alimentares. Os riachos de terras baixas apresentaram um alto consumo de perifiton que foi substituído pelo consumo de material particulado nos riachos de altitude. O consumo de folhiço foi importante em ambas as altitudes e se manteve estável temporalmente. No caso de uso do solo, os riachos inseridos em plantações de eucalipto, seguiram um padrão muito próximo aos riachos florestados. Os padrões encontrados nos riachos de pastagem diferiram de ambas as fisionomias florestais apresentando um baixo consumo de folhiço e influência de plantas C4 na dieta de alguns invertebrados, além de uma grande variação interna explicada pela composição do folhiço e material particulado encontrados nestes riachos.
Several studies show a strong influence of terrestrial environment on streams contained therein. On headwater streams that influence is not just related to chemical and physical variables, but also is directly linked to what the stream metabolism, regulating the direct input of nutrients in the form of litter and particulate matter and internal productivity through light incidence. Factors that are inextricably linked to maintenance of these metabolism and consequently to the biodiversity that exists in these streams. This study, using the isotopic technique of \'delta\'13C and \'delta\'15N and ecological indexes (richness, abundance, diversity, EPT and EPTC) compared Atlantic Forest streams inserted in environments with different characteristics. We compared streams inserted in Tropical Rain Forest of lowlands (50-50 m), foothills of the Serra do Mar and Mountain Tropical Rain Forest (500-1200 m) upland. Also compared streams in different land uses, inserted into a matrix of forest, grassland and eucalyptus. Differences found on isotopic variables showed changes in dietary patterns. The lowland streams showed a high consumption of periphyton that was replaced by the consumption of particulate matter in the upland streams. Consumption of leaf litter was important in both altitudes and remained stable on both seasons. For land use comparison, streams inserted in eucalyptus plantations, followed a pattern similar to forested streams. The patterns found in pasture streams differed from both forest formations, showing a low consumption of leaf litter and influence of C4 plants in the diet of some invertebrates, as well as a large internal variation explained by the composition of litter and particulate matter collected in these streams.

The plasma drifts or electric fields and their structures in the ionosphere affect the accuracy of the present-day space-based systems. For the first time, we have used ionospheric plasma drift data from Jicamarca radar measurements to study the climatology of altitudinal variations of vertical and zonal plasma drifts in low latitudes during daytime. We used data from 1998 to 2014 to derive these climatological values in bimonthly bins from 150 km to 600 km. For the vertical plasma drifts, we observed the drifts increasing with altitudes in the morning and slowly changing to drifts decreasing with altitude in the afternoon hours. The drifts change mostly linearly from E- to F-region altitudes except in the morning hours of May-June when the gradients are very small. The zonal drifts show a highly nonlinear increase in the westward drifts at the lower altitudes and then increase slowly at the higher altitudes. We see a break in the slopes at lower altitudes during the morning hours of March-April and May-June. The E-region zonal drifts, unlike vertical drifts, show a very large variability compared to F-region drifts. We also explored the altitudinal profiles of vertical drifts during late afternoon and evening hours when the electrodynamic properties in the ionosphere change rapidly. For the first time using drifts up to 2000 km, we have shown the drifts increase and decrease below and above the F-region peak before becoming height independent. These structures arise to satisfy the curl-free condition of electric fields in low latitudes. The altitudinal gradients of vertical drifts are balanced by a time derivative of the zonal drifts to satisfy the curl-free condition of electric fields. We have shown how these structures evolve with local time around the dusk sector and change with solar flux. During solar minimum, the peak region can go well below 200 km. The present-day electric field models do not incorporate these gradients, particularly in the evening sectors when they change very rapidly. Very often their results do not match with the observations. Including these gradients along with proper magnetic field models will improve the model results and accuracy of our navigation, communication, and positioning systems.

Le changement climatique rapide auquel nous assistons actuellement est déjà en train de modifier le cycle de vie d’un grand nombre d’organismes. Des études basées sur des modèles d’enveloppe bioclimatique apportent des réponses mais ces prédictions de nouvelles aires de répartition ne tiennent pas compte d’une part de l’adaptation rapide des espèces (plasticité phénotypique et diversité génétique non neutre), et d’autre part des interactions interspécifiques ou de la dynamique des populations. Ce travail de recherche est centré sur les mécanismes permettant la persistance des individus dans un environnement changeant.Nous avons travaillé dans les Pyrénées françaises sur deux espèces à large répartition européenne (chêne sessile et hêtre commun) sur un gradient altitudinal de 1500 m de dénivelé correspondant en moyenne à 8°C d’amplitude thermique. Ce gradient a été répété dans deux vallées parallèles, distantes de 30 km. Basée sur l’étude de traits fonctionnels, nous avons caractérisé les variations altitudinales de traits morphologiques et physiologiques de ces caractères dans des conditions naturelles. Les capacités écophysiologiques apparaissent plus élevée pour le chêne et pour les populations de haute altitude, suggérant une adaptation locale à un environnement stressant. Dans une étude préliminaire, nous avons établi qu’il était nécessaire d’intégrer les variations de pression partielle de dioxyde de carbone et non se concentration dans les mesures d’échanges gazeux. Tous les traits fonctionnels mesurés en populations naturelles varient avec l’altitude. Ainsi la taille des feuilles diminue avec l’altitude tandis que les autres traits augmentent, avec des valeurs de 1.3 à 3.9 fois supérieures entre le haut et le bas du gradient tous traits confondus. Nous avons ensuite cherché à déterminer l’origine de ces variations phénotypiques. Une expérimentation en test de provenance a ainsi permis de déterminer les traits dont la variation in situ était en partie sous contrôle génétique. Les résultats de notre étude montrent que le gradient altitudinal a induit une différenciation génétique au niveau de la croissance, de la phénologie et de traits fonctionnels foliaires pour ces espèces, malgré la proximité des populations étudiées dans leur milieu naturel. Néanmoins, les capacités photosynthétiques pour le hêtre et la surface spécifique foliaire pour le chêne ne montre aucune différentiation génétique, ainsi que la densité stomatique pour les deux espèces. D’autre part, l’expérimentation de transplantations réciproques le long du gradient, a mis en évidence une forte plasticité phénotypique pour les deux espèces, ce qui suggère que les populations peuvent dans une certaine mesure répondre immédiatement aux variations climatiques rencontrées le long de ce gradient. Cependant, tandis que la température optimale pour la longueur de saison de végétation ne semble pas encore atteinte, les populations pourraient réagir négativement à une élévation de la température en terme de croissance. En conclusion, les mécanismes adaptatifs mis en évidence le long d’un gradient climatique naturel, pourraient permettre aux populations de faire face au changement climatique actuel
The rapid climate change, which we are currently witnessing, is already modifying the physiology and distribution of species. Predictions of changes in species distributions do not take evolutionary mechanisms and biotic interactions into account. Our main objective was to assess the inherent adaptive capacities of tree populations by i) quantifying the phenotypic variations of functional traits with altitude and ii) studying the extent to which these variations are environmentally driven (phenotypic plasticity) and/or genetically fixed (adaptation). The study took place in the French Pyrenees along an altitudinal gradient range of 1500 m corresponding on average to 8°C of thermal amplitude. We focused on two broadleaved species with a wide European distribution (sessile oak and common beech). This gradient was repeated in two parallel valleys, distant from 30 km. Altitudinal trends were investigated for several morphological, physiological and phenological traits in natural conditions (in situ), in a common garden experiment and in reciprocal transplant experiments (RTEs). The phenotypic variability observed in situ showed significant altitudinal trends for all the studied traits and followed similar patterns for both species. We established that together with temperature, it was also necessary to integrate the variations of atmospheric gas partial pressure along the altitudinal gradient. In the common garden experiment, our results showed that the altitudinal gradient induced genetic differentiations for growth, leaf phenology and several morphological and physiological traits. This experiment made it possible to demonstrate, for both species, a weaker effect of genetic variations than in situ observed variations, suggesting a strong effect of the environment on leaf functional traits. A higher intrapopulation than interpopulation genetic variability was also observed for all traits. Finally, the reciprocal transplant experiments highlighted a high magnitude of phenotypic plasticity whatever the trait and the species

La forte variation climatique, notamment de la température qui est associée à la distribution altitudinale de certains peuplements d'arbres forestiers peut induire des pressions de sélection divergentes favorisant l'expression de phénotypes différents en fonction de l'altitude. Cette thèse a pour objectif de déterminer si des adaptations locales existent et peuvent être mises en évidence dans un peuplement de mélèze (Larix decidua Mill.) distribué le long d'un gradient altitudinal situé dans les Alpes françaises, à proximité de Briançon. Quatre placettes d'environ 200 mélèzes ont été délimitées à 2300 m, 2000 m, 1700 m et 1350 m d'altitude le long de ce gradient. Une variabilité phénotypique significative a été observée entre ces niveaux altitudinaux pour la plupart des caractères étudiés : circonférence, hauteur de l'arbre, pourcentage d'aubier ainsi que pour toutes les variables microdensitométriques de cernes sauf une (la largeur de cerne). Une analyse de génétique des populations utilisant des marqueurs microsatellites a mis en évidence une faible influence de la dérive génétique sur la diversité génétique et une forte intensité de flux de gènes entre les différents niveaux altitudinaux étudiés. La différenciation génétique inter-altitudes a été estimée à l'aide d'une approche in-situ basée sur les données phénotypiques seules (PST) et comparée à la différenciation observée à l'aide des marqueurs microsatellites (FST). Cette analyse indique que l'hypothèse d'adaptations locales avec l'altitude peut être raisonnablement avancée pour les caractères de hauteur, circonférence, pourcentage d'aubier et densité du bois initial. Au contraire, l'adaptation locale n'apparait pas comme une hypothèse acceptable pour les caractères de largeur de cerne, surface de cerne, largeur du bois final et densité du bois final.

La forte variation climatique, notamment de la température qui est associée à la distribution altitudinale de certains peuplements d’arbres forestiers peut induire des pressions de sélection divergentes favorisant l’expression de phénotypes différents en fonction de l’altitude. Cette thèse a pour objectif de déterminer si des adaptations locales existent et peuvent être mises en évidence dans un peuplement de mélèze (Larix decidua Mill.) distribué le long d’un gradient altitudinal situé dans les Alpes françaises, à proximité de Briançon. Quatre placettes d’environ 200 mélèzes ont été délimitées à 2300 m, 2000 m, 1700 m et 1350 m d’altitude le long de ce gradient. Une variabilité phénotypique significative a été observée entre ces niveaux altitudinaux pour la plupart des caractères étudiés : circonférence, hauteur de l’arbre, pourcentage d’aubier ainsi que pour toutes les variables microdensitométriques de cernes sauf une (la largeur de cerne). Une analyse de génétique des populations utilisant des marqueurs microsatellites a mis en évidence une faible influence de la dérive génétique sur la diversité génétique et une forte intensité de flux de gènes entre les différents niveaux altitudinaux étudiés. La différenciation génétique inter-altitudes a été estimée à l’aide d’une approche in-situ basée sur les données phénotypiques seules (PST) et comparée à la différenciation observée à l’aide des marqueurs microsatellites (FST). Cette analyse indique que l’hypothèse d’adaptations locales avec l’altitude peut être raisonnablement avancée pour les caractères de hauteur, circonférence, pourcentage d’aubier et densité du bois initial. Au contraire, l’adaptation locale n’apparait pas comme une hypothèse acceptable pour les caractères de largeur de cerne, surface de cerne, largeur du bois final et densité du bois final
The strong climatic variation, in particular the temperature variation, which is associated with the altitudinal distribution of certain stands of forest trees, can induce different divergent selection pressure favoring altitude-dependent phenotype expression. The aim of the present thesis is to determine if local adaptation exists and can be identified in an European larch stand (Larix decidua Mill.) distributed along an altitudinal gradient located in the French Alps near Briançon. four plots of about 200 larches were delimited at 2300 m, 2000 m, 1700 m and 1350 m along this altitudinal gradient. A significant phenotypic variability was observed between these altitudinal levels for most characters studied: circumference, tree height, percentage of sapwood and for all the annual-ring microdensity variables except one (ring width). A population genetics analysis using microsatellite markers showed a small effect of genetic drift on the genetic diversity but an intensive gene flow between the altitudinal levels studied. The inter-altitudinal genetic differentiation was estimated using an in-situ approach based on phenotypic data only (PST) and compared with the differentiation observed by means of microsatellite markers (FST). This analysis indicates that the assumption of local adaptation with altitude can be reasonably proposed for the characters of height, circumference, percentage of sapwood and earlywood density. On the contrary, the local adaptation does not appear to be an acceptable assumption concerning characters such as ring width, ring surface area, latewood width and latewood density

La plasticité phénotypique permet aux génotypes de s’ajuster à des variations environnementales. Dans cette thèse nous avons utilisé des caractères de cernes annuels de mélèzes pour estimer la plasticité phénotypique à deux échelles de temps: entre années (chap. 1, plasticité interannuelle) et dans l’année (chap. 2, plasticité intra-annuelle). Dans le chap. 1 nous avons analysé des cernes annuels de mélèzes d’Europe distribués dans quatre placettes le long d’un gradient altitudinal naturel de la région de Briançon, dans les Alpes françaises. La plasticité phénotypique de la croissance radiale et de la densité du bois final en fonction de la température maximale tend à être négative à basse altitude (1350 m) et surtout positive à haute altitude (2300 m), où le mélèze d’Europe semble réagir favorablement à l’augmentation de la température. Aucune tendance altitudinale ne se dégage pour la densité du bois initial, qui présente en majorité une plasticité négative ou nulle. La plasticité phénotypique de la densité moyenne du cerne est intermédiaire entre celle du bois initial et celle du bois final. Dans le chap. 2 nous avons utilisé des courbes de croissance radiale intra-annuelle enregistrées à l’aide de dendromètres automatiques pendant quatre années dans un dispositif combinant plusieurs régimes hydriques et trois espèces de mélèze. Nous en avons extrait des variables de plasticité phénotypique pour la croissance radiale et la dynamique de l’eau dans le tronc en fonction de plusieurs variables climatiques. Toutes variables de plasticité phénotypique et toutes conditions environnementales confondues, l’hybride est un peu plus plastique que le mélèze du Japon et beaucoup plus que le mélèze d’Europe, ce qui traduit sa capacité à reconstituer et à utiliser rapidement et efficacement cette réserve en eau. Nous faisons l’hypothèse que cela contribue à sa plus grande vigueur. De façon générale, il y a autant de plasticités phénotypiques que d’associations caractère phénotypique/variable environnementale. La plasticité phénotypique résume en une seule valeur toute la dynamique d’une réponse particulière. Si en sélection naturelle une plasticité élevée parait constituer un avantage, ce n’est pas aussi évident en sélection artificielle
Phenotypic plasticity is the ability of individual genotypes to adjust to environmental variation. In this thesis we used larch annual ring traits to estimate phenotypic plasticity at two-time scales: between years (chap. 1, inter-annual phenotypic plasticity) and within years (chap. 2, intra-annual phenotypic plasticity). In chap. 1 we analyzed annual rings of European larches distributed in four plots along a natural elevational gradient near Briançon, in the French Alps. The phenotypic plasticity of radial growth and latewood density as a function of maximum temperature tends to be negative at low elevation (1350 m) and distinctly positive at high elevations (2300 m), where European larch seems to react favorably to temperature increase. No elevation trend emerges for earlywood density, which mostly exhibits negative or null phenotypic plasticity. The phenotypic plasticity of mean ring density is intermediate between that of earlywood and of latewood density. In chap. 2 we used intra-annual radial growth curves recorded with automatic point dendrometers during four successive growing seasons in an experimental trial combiningseveral water regimes and three species of larch. From such curves we obtainedphenotypic plasticity variables for radial growth and the dynamics of water in the trunk as a function of several climatic variables. All phenotypic plasticity variables and all environmental conditions combined, hybrid larch is a little more plastic than Japanese larchand much more than European larch, which reflects its ability to quickly and efficiently replenish and use his water reserve. We hypothesize that this contributes to its greater vigor.In general, there are as many types of plasticity as there are combinations of phenotypic traits and environmental variable. Phenotypic plasticity summarizes in a single value all the dynamics of a particular response. While in natural selection a high plasticity seems to be an advantage, it is not so evident in artificial selection

Un grand nombre d’espèces ont déjà subi des changements phénologiques ou des déplacements de leurs distributions en réponse aux changements anthropogéniques du climat. Comprendre comment les espèces vont réagir aux changements climatiques représente toutefois une tâche complexe puisqu’il existe une grande variabilité dans ces réponses. Cette variabilité peut être attribuée au fait que plusieurs facteurs influencent les réponses des espèces aux changements climatiques et que ces facteurs varient eux-mêmes spatialement. Dans ce mémoire, l’intensité d’interactions biotiques, soit la pollinisation et l’herbivorie, ainsi que la phénologie de la floraison sont comparées le long d’un gradient altitudinal menant à la limite de distribution altitudinale pour deux plantes de sous-étage, Erythronium americanum et Trillium erectum. Je teste en premier lieu si l’intensité de l’herbivorie et de la limitation pollinique augmentent à la limite de distribution altitudinale des espèces. Si cela est le cas, ces interactions peuvent limiter ces distributions et ainsi, le potentiel des espèces à déplacer leurs distributions face aux changements climatiques. Les résultats démontrent une augmentation de l’herbivorie et de la limitation pollinique à la limite de distribution altitudinale de T. erectum. Toutefois, la limitation pollinique devrait avoir un effet minime sur la limite de distribution altitudinale de cette espèce puisque le succès reproducteur des plantes est très peu diminué à cette limite. En se basant sur des études antérieures, la proportion d’herbivorie subie à proximité de la limite de distribution altitudinale devrait avoir des effets démographiques considérables et devrait ainsi affecter cette limite. Concernant E. americanum, l’herbivorie et la limitation pollinique sont restés constants et de faible intensité le long du gradient altitudinal. Ensuite, en disposant de quatre années de données de la phénologie de la floraison le long du gradient altitudinal étudié, je vérifie de façon préliminaire si le potentiel de flux génique est affecté par la date d’initiation du printemps, ce dernier se produisant plus hâtivement en réponse aux changements climatiques. Les résultats démontrent une diminution de l’écart temporel entre les pics de floraison des populations d’altitudes différentes lors d’années aux printemps plus hâtifs, ce qui indique une différence interpopulationnelle dans la réactivité phénologique. Toutefois, cette différence temporelle n’a pas entraîné une diminution du potentiel de flux génique. Je présente également une nouvelle méthode de mesure du potentiel de flux génique qui permet d’estimer plus efficacement ce dernier à partir de la phénologie comparativement aux méthodes actuellement utilisées.

La differenciation genetique au sein des especes est un phenomene courant chez les vegetaux qui sont fortement dependants des conditions de leur environnement. Cette differenciation qui necessite souvent un isolement au moins partiel des populations, sera ecotypique si elle depend aussi des pressions de selection du milieu. Les conditions climatiques extremes des milieux d'altitude et leur heterogeneite generent des differenciations ecotypiques et chromosomiques. Celles-ci sont etudiees, en vanoise, chez deux especes communes des milieux d'altitude et appartenant a des complexes polyploides, le lotier alpin et le dactyle alpin. En vanoise, le lotier alpin presente deux entites chromosomiques (diploide entre 2000 et 3000 m et tetraploide entre 1800 et 2500 m) qui peuvent se trouver en parapatrie voire en sympatrie. L'origine autopolyploide du tetraploide et les flux de genes qu'il entretient avec le diploide et certains cultivars de lotier cornicule introduits dans la region, sont mis en evidence par une caracterisation genetique (caryologie, variation allozymique et de l'adn chloroplastique), morphologique et phenologique. Le dactyle alpin tetraploide prealablement decrit dans les alpes suisses et italiennes, a ete localise en vanoise ou il colonise des habitats arides, en exposition sud, sur forte pente et sur calcaire dolomitique. Une caracterisation morphologique, phenologique et allozymique, a permis de montrer l'existence de flux geniques entre les individus de cette sous-espece alpine et ceux de la sous-espece ubiquiste glomerata tres repandue dans la region. Un avantage selectif des dactyles alpins au niveau de la capacite a produire des graines dans leur milieu, mis en evidence lors de transplantations reciproques, associe a un decalage phenologique partiel, peut expliquer le maintien des deux sous-especes en tant qu'entites distinctes dans une meme region
Genetic differentiation among populations is a frequently observed phenomenon in plant species. Such differentiation often depends on the degree of isolation between populations but also, where environmental selection pressures are strong, can lead to local adaptation and the production of ecotypes. Severe climatic conditions and heterogeneity prevailing in high elevation habitats are known to induce ecotypic and chromosome differentiation. In this thesis the patterns of population differentiation have been studied in two widespread species belonging to two polyploid complexes, lotus alpinus (d. C. ) scleicher and dactylis glomerata l. In the vanoise region of the alps in the vanoise, two chromosome entities of l. Alpinus (diploid between 2000 and 3000 m and tetraploid between 1800 and 2500 m) may occur in parapaty or in sympatry. The autotetraploid origin of the alpine tetraploid and gene exchange with its related diploid and also l. Corniculatus cultivars introduced into this region have been documented based on genetic (caryology, allozymes and cpdna variation), morphological, and phenological characteristics. The alpine dactylis (d. Gl. Subsp. Reichenbachii), previously described in the swiss and italian alps was observed in the vanoise where it is confined to xeric, dolomitic south-facing alpine meadows above 2100 m. Morphological, phenological and allozyme studies indicate that gene flow occurs between individuals of this alpine entity and individuals of the subspecies glomerata, which is widely distributed in the region. A reciprocal transplant experiment showed a selective advantage to alpine dactylis which produced relatively more seeds in the severe habitat. In combination with differences in flowering time between the two subspecies, such differences in fertility may explain the maintenance of the two interfertile subspecies as distinct entities in the same region

Southern Africa is characterised by an unpredictable environment with daily and seasonal temperature fluctuations. As a local or non-migratory endothermic species occurring over an altitudinal gradient from the Drakensberg to the coast of KwaZulu- Natal in southern Africa, Amethyst Sunbirds (Chalcomitra amethystina) experience challenging thermal conditions and increased energetic stress as a result of ambient temperature variation. Flexibility of metabolic rates within a species allows for the colonization of different habitats along an altitudinal and thus temperature gradient. It was predicted that over this altitudinal gradient Amethyst Sunbirds would exhibit variation in metabolic rates, particularly basal metabolic rates, pre- and postacclimation, as well as variation in hematocrit levels in winter and summer trials. It was also predicted that Amethyst Sunbirds would exhibit seasonal variation in metabolic parameters. Sunbirds were caught in a winter and summer season (2006-2007) using mist nets in three locations; Underberg (1553 m), Howick (1075 m) and Oribi Gorge (541 m). Upon capture, metabolic rate was measured indirectly by quantifying oxygen consumption (VO2) using flow through respirometry, at 5 and 25°C. Birds were then acclimated at 25°C for 6 weeks on a 12L:12D cycle. VO2 was measured postacclimation at 8 different temperatures (15, 5, 10, 20, 30, 28, 25 and 33°C). Hematocrit levels were taken pre-acclimation and pre-release. Winter and summer data were compared. In the winter trials it was found that there was little variation in VO2 between individuals from the same locality, whereas significant variation was observed at the same temperatures between localities and thus between altitudes. The subpopulation from the highest altitudinal site had the highest basal metabolic rate (BMR). Summer trials showed that metabolic rates did not differ significantly between altitudinal subpopulations of Amethyst Sunbirds, however, BMR was observed to decrease as altitude decreased. The comparison of seasonal data showed that Amethyst Sunbird subpopulations from Underberg and Howick showed higher post-acclimation VO2 values per temperature in winter than in summer trials. Post-acclimation resting metabolic rate (RMR) values for Howick subpopulations were generally higher in winter than in summer, Underberg Amethyst Sunbirds showed a significant difference between summer and winter RMR at 5 and 10°C and Howick sunbirds showed a significant difference in RMR between seasons at 5°C. The Oribi Gorge subpopulation, however, showed no significant differences in metabolic rate between any temperatures when comparing a summer and a winter season. Thermal neutral zones of all of the subpopulations of Amethyst Sunbirds shifted between the winter and summer trial period. This study thus emphasized the need to understand plasticity in metabolic rates and acknowledge altitudinal and seasonal differences within a species, in order to make accurate predictions about a species thermal physiology and responses to changes in ambient temperatures. In particular, the variation in BMR, which is usually used as a species specific value, should be acknowledged in comparative studies of avian metabolic rates or in climate change models.
Thesis (M.Sc.) - University of KwaZulu-Natal, Pietermaritzburg, 2007.

碩士
國立臺灣大學
植物學研究所
83
The purpose of this study is to understand the β-diversityalong an altitudi-nal gradient. A one-hectare transect, which is 500 m long and 20-40 m wide at altitudes of 220-467 m, was established on the northwestern ridgeof Nanjenshan, Kenting National Park. Inventory of woody plants in the transect was conducted, and DBH, height,and growth condition for each individual were recorded. A total of 139 woody species, belonging to 49 families and 91 genera, were recorded. Among them 99 were trees, 30 shrubs and 10 lianas. The most dominant sprcies is ~u2;Ilex cochinchinese~u1; with an important value (IV) of 7.61% and 533 individuals; the second dominant one is Syzygium euphlebium with an important value of 6.02% and 200 individuals. In general, the forest showed a strong dominance, that is, 43.55% of the dominance were shared by the first ten species. The result of Detrended-Cerresponding Analysis (DCA) showes that the transect can be divided into three vegetation zones along the altitudinal gradient. Four types of species distri- bution pattern were classified based on the peak of dominance along the altitudinal gradient. Dominance at the family level also tends to change along the altitudinal gradient reveals that a sharp transition from semitropical to temperate forest type. 15 species of six genera are found with congeneric niche differensiation along the altitudinal gradient. The slope of regression formula, Y=-0.0019x+0.5925, which is plotted by community coefficient to altitudinal differencies, is β-diversity. These result suggest high α-diversity and community changes when the altitudinal varies over the range of 300 m.

碩士
東海大學
生命科學系
102
The aim of this study was to know how Rana latouhii, Rana swinhoana, and Rana sauteri change their body size patterns through different altitudes, and also the possible mechanism causing the differences. This study was conducted from October 2009 to October 2011. We sampled six districts from sea level to 3000 m (500 m per district). Within each district, we tried to collect 30 individuals for both males and females. Upon catching the animals, we measured the body length and clipped the longest toe of its right hind foot, using skeletochronology technique, we acquired their life-history traits including metamorphic size, the growth rate before sexual maturity, the age of sexual maturity, and age. Our results showed that there was no significant difference between body size and life-history traits among different altitudes in R. latouhii. However, the body size of R. swinhoana increased with altitude, which fits the Bergmann’s pattern. In the species, the age of sexual maturity and age were the main factors affecting body size. Different from R. swinhoana, the male and the female R. sauteri showed different body size patterns. The body size of male R. sauteri fitted counter Bergmann’s pattern in that body size decreases with altitude, while the female’s body size showed no difference among different altitudes. In males, metamorphic size and the growth rate before sexual maturation decreased with altitudes were the main factors for explaining body size pattern. However, in females, the age of sexual maturity and age played more important roles. Older but lower smaller growth rate of sexual maturity along with altitude attributes to the indifference of body size in female R. sauteri. Overall, my results showed that three species from the same class within the same area, because of different altitude distribution, have emerged different life-history traits, and therefore, different patterns of body size variations among altitude. My results indicate that the effect of altitude on body size is a multi-factors processes, which cannot be explained alone by phylogenetic constraint, localized isolation, or the quality of food source.

碩士
國立臺灣大學
森林環境暨資源學研究所
99
Widely-distributed plants might have mechanisms enabling them to survive in a wide range of climatic and environmental conditions. The purpose of this research was to find out whether the morphological and physiological characteristics of four plant species change with the altitudinal environments and seasons, and what are the significance of these changes to the plants. I collected healthy leaves of populations of four native widely-distributed plants along altitudinal gradients on the eastern side and western side of Central Taiwan. The four species were: Pinus taiwanensis, Alnus japonica, Miscanthus floridulus, and Plantago asiatica. The elevation intervals between adjacent sample sites were around 300-500 m. I collected leaves in Nov. of 2009, and Jul. of 2010. This study include three parts: (1) To compare leaf stable carbon (δ13C) and nitrogen isotope ratio (δ15N), and carbon (C%), and nitrongen (N%) content of populations of the four species in different altitudes. (2) To compare δ13C, δ15N, carbon (Carea) and nitrogen (Narea) content per leaf area and morphological characteristics, including leaf mass per area (LMA) and stomatal density of M. floridulus and Pla. asiatica along altitudinal gradient between two different seasons. (3) To compare the geographical distribution, and morphological traits between Pla. asiatica populations with glabrous and pubescent leaf form. According to the δ13C analysis, M. floridulus is a C4 plant, the other three species are C3 plants. The results of the first part also showed that the δ15N of A. japonica and the δ13C of M. floridulus had positive correlations with altitudes. Among three C3 species, Pla. asiatica had the lowest δ13C, indicating its long-term water use efficiency was lower than that of A. japonica and Pin. taiwanensis, or the δ13C of its carbon sources were lower. The δ15N values of A. japonica were significantly more negative than other three species, I speculated it is caused by the impact of its symbiotic rhizobium. Results of the second part revealed that leaves of Pla. asiatica populations at high altitudes had significantly higher δ13C in July than in Nov.. And a positive correlation between δ13C and altitudes was found in samples collected in July 2010. The main reason why Pla. asiatica had higher δ13C in July 2010 and in higher altitudes might due to its increases in LMA. The LMA of Pla. asiatica in July was higher than that in November, indicating that it was harder for CO2 to diffuse through the leaves in July. A positive correlation between leaf δ13C and altitude was found in western population of M. floridulus, Narea of M. floridulus also showed a generally positive correlation with altitude while LMA didn’t, it suggested that the increase of Narea was not caused by LMA , but due to more allocation of N into photosynthetic machinery. A significant correlation between δ13C and LMA was found, which suggests that LMA might be the main reason causing the variation of δ13C in M. floridulus. The results of the third part showed that Pla. asiatica individuals with glabrous, pubescent, and marginal pubescent distributed in all sample sites except for the site White Iron Gate. Further analysis revealed that there were no significant differences between glabrous and pubescent leaves in chlorophyll content, LMA, SD, δ13C、Narea and Carea.According to the result, the appearance of trichomes may have no significant effects on reducing water loss. Further study is needed to understand the functions of trichomes on leaves of Pla. asiatica.

博士
國立臺灣大學
動物學研究所
90
Sauter''s frog, Rana sauteri Boulenger, 1909 in the centro-western part of the Central Mountain Range of Taiwan at elevations of 300 m to 2360 m showed obvious altitudinal clines in reproductive and life cycle traits. With the increase in elevation, the breeding season, the period of calling, aggregation and egg deposition of mature frogs, shifted from fall and winter (October to December) to spring (May), while the breeding period decreased but the larval period increased. Also, adult females of high elevation were larger and produced smaller clutch size but larger eggs and tadpoles. The temperature experiment showed that low temperature in winter at high elevations and high temperature in summer at low elevations may be the primary environmental factors that define the breeding success of the species. The patterns of growth and development of tadpoles of R. sauteri at Chitou (1,100 m) and Mienyueh (2,350 m) were investigated. In Chitou, tadpoles of different developmental stages can be found from December to March, indicating that the growth and development of tadpoles are not synchronized. In Mienyueh, the majority of tadpoles ceased to develop after reaching Phase 2 in August even though they did not stop growing until December. Tadpoles resumed growth and development at the following spring, and reached metamorphosis by June. It appears that tadpoles ceased to develop early enough so that they could channel a greater proportion of energy into growth to get larger size for better survival rate in cold winter. In addition, tadpoles in Mienyueh ceased to develop early enough so that they could overwinter with Phase 2, the more simple type, to reduce the risk of limb frostbite and larval mortality during the extreme cold temperatures. Our results suggest: 1) R. sauteri was long-term selected by the environment, resulted in the populations of high elevation bred in spring and the populations of low elevation bred in fall and winter to increase the growth and survival rate of tadpoles, 2) the different patterns of larval growth and development between populations to increase the rate of metamorphosis, are adaptive strategies for the best survival of tadpoles in the mountains of Taiwan.