Island biogeography theory predicts that the patterns and distributions of spatially isolated populations are governed by large scale processes. The high elevations forests in the Southern Appalachians represent a series of naturally fragmented islands that harbor many isolated populations of species at the southern limits of their range. Understanding the governing forces of population dynamics in this region will enhance the probability of species persistence in the face of threats such as global warming and human development. We surveyed bird populations across multiple elevations in Virginia and combined this with a multi-scale habitat analysis to determine influences of species presence and species richness. We detected 101 species across the elevation gradient, including 12 species with special conservation status and ten species whose presence increased with increasing elevation. These ten elevation sensitive species responded to habitat variables at both the microhabitat and landscape scale, with species-specific patterns of habitat variable correlation emerging. Habitat type was least effective in predicting species presence for any elevation sensitive species. Species richness declined over the elevation gradient until the highest elevations, where this trend reversed and richness began to increase. This pattern was driven by an increase in short-distance migrants beginning at mid-elevations, which ultimately overpowered a corresponding decrease in long-distance migrants beginning at similar elevations. Habitat analysis linked these patterns to a preference of short-distance migrants for smaller, more isolated non-forested patches, and a historical lack of persistence for long-distance migrants. Conservation and management decisions for the region should focus on a multi-scale approach that preserves all habitat types for continued species presence and high species richness, although the persistence of particular elevation sensitive species is compounded by unique species-habitat relationships and the perception of islands as species-specific. Continued monitoring of these fragmented populations in light of both short- and long-term threats which span multiple scales of influence will maintain high species richness and ensure the persistence of crucial breeding habitat. / Master of Science

Altitudinal gradients represent useful tool for investigating diversity patterns and processes affecting species richness and turnover along steep gradient of conditions at relatively small scale. The aim of my study was to compile a complete checklist of birds for elevational gradient of Mt. Cameroon rainforests (300 - 2300 m a.s.l.) and to analyse distribution of species diversity, species turnover, elevational ranges and relationships between elevational distribution of species and their range size, body weight or diet type. Species richness on the elevational gradient of Mt. Cameroon decline monotonically with some plateau at 600 - 1000 m a.s.l. Changes of community composition along the gradient are caused mainly by species turnover at low elevations, which contrast to pattern above 1200 m a.s.l. where the betadiversity is influenced mainly by continual species loss (nestedness). Species elevational ranges increase with increasing elevation, which is in agreement with elevational Rapoport's rule. Species breeding at higher elevations have smaller geographical ranges, restricted to isolated islands of montane rainforests. Numbers of insectivorous species are rapidly decreasing with increasing elevation, proportion of nectarivorous species is rather invariable and number of granivorous species...

This thesis explores the role mutualist pollinators and their symbionts play in the genetic structuring and speciation of their host plants along an elevational gradient in Papua New Guinea. Using the fig and fig-wasp mutualism as a model system, we employed high-throughput sequencing techniques to explore fine-scale population genomics of both fig and wasps along their elevational range. We found there to be clear lowland and highland clustering of tree populations along the gradient, often with a mid-elevation contact zone. In the case of the pollinating wasps, we retrieved the same clustering except in this case, the genetic difference between clusters was high enough as to consider them as separate species. This result supports evidence from other studies challenging the cospeciation paradigm of one wasp species per fig species. In addition, we explore ecological traits which may promote, or at least, maintain, reproductive isolation between fig (sub)species along with behavioural preference tests from pollinating wasps. In order to further investigate the mechanisms promoting wasp speciation along the gradient, we describe Wolbachia infection status as well as strain type. Wolbachia-induced cytoplasmic incompatibility (CI) is often invoked as a possible speciation agent since it can rapidly provoke and maintain reproductive isolation between otherwise freely interbreeding insect populations. Finally, we explore non-pollinating fig wasp (NPFW) diversity along the gradient for a subset of our focal species. Our study reveals that there is a tight relationship between NPFW diversity and host species, and a mid-elevation peak.

Living (biotic) and non-living (abiotic) factors drive the function of ecosystems across a variety of scales from the root-soil interface to the watershed. Biotic and abiotic global change pressures such as increasing temperature and invasive species are shifting how ecosystems function. Thus, exploring and understanding how these factors shape function across the landscape is an important research area. For example, climate change both directly and indirectly affects soil microbial functions – such as carbon mineralization and nitrogen transformations – through increasing activity under warming and altering inputs to the soil through species composition changes. Mountains provide a useful tool for studying relationships among biotic and abiotic factors because climate and species diversity shift along gradients. Here, I measured carbon and nitrogen soil processes as well as microbial extracellular enzyme activity along an elevational gradient to explore how changes in climate, edaphic properties, and biotic composition affects ecosystem function. As expected, climate and species composition varied in predictable ways along the gradient – actual evapotranspiration declined, and conifer dominance increased. Soil functions also shifted along the gradient. Potential carbon mineralization increased with elevation and with conifer dominance. Potential nitrogen mineralization rates increased with elevation and with conifer dominance. Surprisingly, there were few predictors for potential soil nitrification, which increased only with soil functional diversity. While temperature and moisture availability drive ecosystem function at broad scales and biotic factors typically drive function at the regional scale, we saw that function of soils at the mountain watershed scale was best explained by a combination of both abiotic and biotic factors.

Orientadores: Kikyo Yamamoto, George John Shepherd / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-15T02:40:57Z (GMT). No. of bitstreams: 1 Bertoncello_Ricardo_M.pdf: 8895754 bytes, checksum: 5b50a52fbb7e96dfd8126d57935601cf (MD5) Previous issue date: 2009 / Resumo: A classificação e a delimitação das diferentes formações fitogeográficas que ocorrem no domínio da Mata Atlântica nas regiões Sul e Sudeste do Brasil constituem um desafio para botânicos, ecólogos e fitogeógrafos. A distribuição atual destas formações está relacionada ao histórico de ocupação das áreas e a complexos gradientes ambientais, que ocorrem nos sentidos horizontal (latitudinal, longitudinal e edáfico) e vertical (altitudinal). Visando a contribuir para o conhecimento das formações florestais que integram a Mata Atlântica, este trabalho foi realizado no Morro do Cuscuzeiro (Ubatuba-SP) com os objetivos de: (1) descrever as variações florísticas e estruturais nas comunidades arbóreas em função da altitude, e verificar se existe uma Floresta Nebular que possa ser discriminada por parâmetros florísticos e estruturais; e (2) verificar a situação fitogeográfica das comunidades encontradas neste local no contexto da Mata Atlântica nas regiões Sul e Sudeste do Brasil. O Morro do Cuscuzeiro se situa no Núcleo Picinguaba do Parque Estadual da Serra do Mar (23° 18' 14" S e 44° 47' 16" W) e possui 1277m de altitude. O gradiente altitudinal foi representado por amostras de quatro cotas altimétricas, 820m, 970m, 1120m e 1270m, obtidas em 10 parcelas de 10 x 10 m em cada cota, exceto na mais alta que foi dividida em duas 'sub-cotas' com 5 parcelas cada. O critério de inclusão amostral da flora arbórea foi de 15 cm de CAP (exceto nas duas 'sub-cotas' superiores, 10 cm de CAP). Em sentido base-topo, foi verificada diminuição na riqueza, na diversidade, na altura, no diâmetro e no volume das árvores, e aumento na densidade. Uma mudança abrupta na composição da comunidade arbórea foi detectada a 1120m, acima da qual aparece uma formação que identificamos como Floresta Nebular, em substituição à floresta de encosta da Serra do Mar, que ocorre abaixo daquela altitude. As espécies destas duas formações florestais foram inseridas em uma matriz de 1546 espécies registradas em 112 levantamentos de 78 localidades do domínio da Mata Atlântica nas regiões Sul e Sudeste do Brasil. As análises multivariadas resultaram em cinco grupos de levantamentos: 1-Florestas Nebulares; 2- Florestas da província costeira (posteriormente sub-dividido em (a) Florestas de encosta e (b) Florestas de topo de morro e florestas da planície costeira); 3-Florestas de Araucária; 4-Florestas Semi-decíduas; e 5- Florestas Semi-decíduas Montanas. As formações encontradas no Morro do Cuscuzeiro foram incluídas nos grupos das Florestas Nebulares (de 1120m e 1270m) e das florestas de encosta da província costeira (820m e 970m), o que reforçou os resultados da análise dos dados locais, mostrando que pequenas diferenças em altitude podem resultar em mudança abrupta na composição das comunidades, evidenciada pela presença de espécies de distribuição disjunta que são compartilhadas com outras formações de Florestas Nebulares das regiões Sul e Sudeste do país / Abstract: The classification and delimitation of different vegetational formations into a phytogeographic system in Brazil has been a challenge to ecologists, botanists, and phytogeographers. The current distribution of these formations is related to historical process of land use and complex environment gradients, occurring in horizontal (latitude, longitude and edafic) and vertical (altitude) ways. The aims of this study were (a) to describe the changes in floristic composition and structure of tree species along an elevational gradient on Morro do Cuscuzeiro, Ubatuba (SP), and to verify the occurrence of a Cloud Forest that can be discriminated by floristic and structural paremeters; and (b) to analyze the phytogeographic position of the communities found in this mountain in relation to other surveys of the Atlantic Rain Forest domain in Southern and Southeastern Brazil. Mountain Cuscuzeiro is located in the Serra do Mar State Park (at 23° 18' 14" S, 44° 47' 16" W it is 1277m in height). A survey of tree species was made in four elevational levels, 820m, 970m, 1120m, and 1270m, using 10 samples of 10x10m on each level, except on the higher one, which was sub-divided in two sub-levels whith five samples on each. The sampling criterion was 4,8cm of DBH (except in the two higher sub-levels, where 3,2cm of DBH was used). The analysis resulted in consistent groups at the different levels, indicating a strong altitude influence on the floristic composition. An abrupt change of the vegetation was identified at 1120m, from where a typical Ombrophilous Dense Forest (slope forest from 820m to 970m) shifted into a Cloud Forest formation (1120m to 1270m). These two formations were inserted in a matrix made by a total of 1546 species of 112 surveys from 78 locations of Atlantic Rain Forest domain in southern and southeastern Brazil. The multivariate analysis resulted in five groups of samples: 1- The Cloud Forest; 2- The coastal province (further subdivided into (a) the slope forests and (b) a subgroup composeded by the mountaintop and the coastal plain forests); 3- The Araucaria Forest; 4-The Semi-Deciduous Forest; and 5- The Montane Semi-Deciduous Forest. The formations found on Mt. Cuscuzeiro were included in the groups of the Cloud Forest (from 1120m to 1270m) and of the Coastal Province (from 820m to 970m), which reinforced the results of the local elevational gradient analysis, showing that minor changes on altitude can lead to abrupt changes in community composition due to the occurrence of species with disjunct distribution that are shared with other Cloud Forest formations of southern and southeastern Brazil / Mestrado / Biologia Vegetal / Mestre em Biologia Vegetal

No description available.

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.

<p>  </p> <p>Rapid climate change on a global scale is posing a considerable threat to forest biodiversity. Assessing physiological and genomic backgrounds of each tree is crucial for informing conservation and mitigation strategies to evaluate species or populations' vulnerability and adaptive capacity under climate change. The goal of my dissertation research was to use morpho-physiological and molecular approaches in combination with genomic background, as a backbone knowledge for enhancing the restoration and conservation of different hardwood tree species. The same approaches also led to a better understanding of mitigation strategies of tree species to evaluate their vulnerability and adaptability under climate change. To do so, the native <em>Juglans</em> species (<em>J. cinerea</em> and <em>J. nigra</em>), local species (Arizona walnut<em>; J. major, </em>California walnut; <em>J. hindsii</em>), exotic species (Persian walnut, <em>J. regia</em>) and its F1 interspecific hybrids were used as a case study to evaluate the level of cold hardiness in <em>Juglans</em>. Hybridization can integrate biotic and abiotic tolerance in plants and could be a potential forest restoration and conservation tool. Evidence from past studies in some F1 interspecific hybrids indicates that naturalized hybrids of Persian walnut with black walnut or butternut have higher level of tolerance to lower temperature than Persian walnut. The potential cold tolerance of native, local, exotic <em>Juglans</em> species and F1 interspecific hybrid using field, electrolyte leakage, qPCR, and genome analysis was investigated, and results presented in chapter 2. Differences in cold hardiness were observed in tested <em>Juglans</em> species, <em>J. regia</em> as an exotic species and <em>J. major</em> from Arizona maladapted in West Lafayette, Indiana. No sign of cold damage was observed in F1 interspecific hybrids or native species. Using morpho-physiological, molecular, and genome data, we confirmed that molecular and morpho-physiological data were highly correlated and thus can be used to characterize cold hardy trait in <em>Juglans</em> species. </p> <p>Although the native <em>Juglans</em> species are cold tolerant, with current trend of climate change and rapid tree migration to the northern range, it is not easy to predict how <em>Juglans</em> species may adapt to new environments and response to other biotic and abiotic stresses in future. A reference-genome assembly for nuclear and chloroplast genomes and cold hardy genes is presented in chapter 3. We used re-sequence genomes of 170 individuals collected from 20 <em>Juglans</em> species and <em>Carya</em> (as an outgroup) of the Juglandaceae family distributed in temperate-tropical forests of America and Asia. We integrate genome and temperature variables to identify a set of associated single-nucleotide polymorphisms (SNP), structural variations, and the geographical distribution of the variants in the genes related to local adaptation of <em>Juglans</em> across latitudes. Phylogeny analyses revealed that <em>Juglans</em> species were sorted based on their origin using the nuclear genome, cold-hardy genes, and organellar genome. <em>Juglans regia</em>, a native species of Asia and Europe, was distinct from other species and exhibited less genetic diversity than <em>Juglans</em> spp. of North America, based on whole genome and cold-hardy gene analysis. We identified the black walnut as a more diverse species and the California walnut and Persian walnut (<em>J. regia</em>) as less diverse species using selective sweep and heterozygosity analysis. Within <em>Juglans </em>species, those from colder areas exhibited higher diversity of cold hardy genes compared to the ones from warmer regions. Differences in genetic diversity among continents and latitudes did not follow a clear trend. Still, the level of gene diversity of <em>Juglans</em> from North America is higher than the species that originated in eastern Asia. We can use 65,000 nuclear SNPs variants in an ecological modeling system to predict genetic diversity and spatiotemporal shift of <em>Juglans</em> species in response to future climate change. These SNPs variants are helpful for forest tree breeding programs with aims such as marker-assisted selection (MAS), conservation or assisted migration in future.  </p> <p>Based on the findings of chapter 2 and 3, black walnut is the most diverse species with high genetic diversity in comparison with other <em>Juglans</em> species distributing across eastern forest of the USA. However, deeper knowledge of how this genetically diverse species will be affected by climate change is crucial. In chapter 3, we projected black walnut's current and future basal area. Utilizing machine learning, we tested different models using more than 1.4 million tree records from 10,162 Forest Inventory and Analysis (FIA) sample plots and 42 spatially explicit bioclimate and other environmental attributes. Ultimately, we used random forests (RF) model to estimate the basal area of black walnut under climate change. The mean of annual temperature and precipitation, potential evapotranspiration, topology, and human footprint were the most significant variables in prediction of basal area. Under two emission scenarios (Representative Concentration Pathway 4.5 and 8.5), the RF model projected that black walnut stocking will increase in the northern part of the current range in the USA by 2080, with a potential shift of species distribution range. However, uncertainty remains due to unpredictable events, including extreme abiotic (heat, drought) and biotic (pests, disease) occurrences. Our models can be adapted to other hardwood tree species to predict tree changes in the basal area based on future climate scenarios.  </p> <p>A similar approach of chapter 2, with a slightly different freeze test (whole plant freezing test) and use of cold-acclimated seedling was used in chapter 4. For cold acclimation, seedlings exposed to air temperatures progressively lowered for eight weeks (from 25.6/22.2 ºC to 8/4 ºC, day/night) and non-acclimated seedlings from sea level to 2,300 m, in tropical Hawaiʻi, USA to evaluate cold tolerance of koa. We also investigated gene expression using qPCR and wideseq sequencing in this study. Freezing tolerance varied significantly in non-acclimated versus cold-acclimated treatments across the elevation cline using the whole plant physiology-freezing test and gene expression. The level of freezing tolerance and the elevation at which seeds were collected were consistent with the frequency of freezing tolerance genes to facilitate variation interpretation in cold-hardy phenotypes. Findings of physiology and molecular data analysis for freezing tolerance of koa across the elevation gradient of the Hawaiian Islands provides insight into natural selection processes and will help to support forest restoration efforts. </p> <p>  </p>

No description available.

Pygmy tarsiers (Tarsius pumilus) of Central Sulawesi, Indonesia are the only species of tarsier known to live exclusively at high altitudes. This study was the first to locate and observe multiple groups of this elusive primate. This research tested the hypothesis that variation in pygmy tarsier behavior and morphology correlates with measurable ecological differences that occur along an altitudinal gradient. As a response to decreased resources at higher altitudes and the associated effects on foraging competition and energy intake, pygmy tarsiers were predicted to exhibit lower population density, smaller group sizes, larger home ranges, and reduced sexually selected traits compared to lowland tarsiers. Six groups containing a total of 22 individuals were observed. Pygmy tarsiers were only found between 2000 and 2300 m, indicating allopatric separation from lowland tarsiers. As expected, the observed pygmy tarsiers lived at a lower density than lowland tarsier species, in association with decreased resources at higher altitudes. The estimated population density of pygmy tarsiers was 92 individuals per 100 ha, with 25 groups per 100 ha. However, contrary to expectation, home range sizes were not significantly larger than lowland tarsier home ranges, and average NPL was smaller than those of lowland tarsiers. The average home range size for the observed pygmy tarsiers was 2.0 ha, and the average nightly path length (NPL) was 365.36 m. Pygmy tarsiers exhibited a nonrandom, clumped distribution near forest edges. While insect abundance and biomass were found to decrease as altitude increased, insect abundance and biomass was higher along anthropogenic edges. Thus, tarsiers within the study area may mitigate the decreased availability of insects at high altitudes by remaining close to forest edges, which in turn may be related to smaller than expected home range sizes. Further, estimates of pygmy tarsier abundance may be inflated because of increased insect abundance along anthropogenic edges. Contrary to the prediction for smaller group sizes as a response to feeding competition, the observed pygmy tarsiers lived in relatively large groups with multiple adult males. However, in support of the prediction for energetic constraints on body proportions, the observed pygmy tarsiers did not exhibit sexually selected traits. The pygmy tarsiers exhibited low sexual dimorphism and small relative testes mass, a trend opposite from lowland tarsier species, which may indicate a constraint on the development of those traits. Considered together, these results suggest that the observed pygmy tarsiers have adapted to life in an environment with limited resources. Future studies should explore the possible contributing effects of seasonality and topography.