Dracula orchids are hypothesized to rely on mushroom mimicry for pollination. These orchids look and smell like mushrooms and are pollinated by mushroom-associated flies in the family Drosophilidae. Dracula includes over 130 species, representing a significant radiation, yet there has never been a systematic study of their pollination biology. Elucidating the processes and mechanisms of pollination in these flowers will broaden our understanding of mimicry within the Orchidaceae, a family well known for its diverse pollination strategies, as well as add to the growing literature on the evolution and maintenance of communication signals. In this study we demonstrate the co-occurrence of the mimics and the putative mushroom models, which is important for evolution by natural selection. We also showed that the resemblance to mushrooms is in fact adaptive, a requisite for floral mimicry. We did this by determining that insect visitors are required for pollination and subsequent fruit set with a hand pollination experiment. We also measured increased visitation rates to the orchids when adjacent to mushrooms. The mechanisms whereby plants attract pollinators can be diverse and often multi-modal, particularly in deceptive systems. Dracula orchids are no exception, with both visual and olfactory signals contributing to the overall success in attracting visitors. We used a series of experiments, first selectively masking the visual and olfactory cues successively, and then using 3D-printed artificial flowers to further disentangle these cues and determine their effect in combination. Upon confirmation that both play a role, we dissected each aspect further. We utilized the artificial flowers to determine the roles of color, contrast, and pattern and employed gas chromatography-mass spectroscopy to identify the volatile signals. The results show that fine-scale contrast is critical to the visual component and that these flowers produce the volatile `mushroom-alcohol' (1-octen-3-ol) in their labella. Finally, we specifically address the hypothesis of brood-site mimicry by using a combination of field observations, insect collections, and rearing studies. The flies gain shelter, a rendezvous location, and food from the flowers. However, no mushroom visiting flies hatched from the flowers, suggesting this may be a brood-site mimicry. This dissertation includes previously unpublished co-authored material. / 2015-09-29

Thesis (M. S.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2009. / Committee Chair: Rong Fu; Committee Member: Robert Dickinson; Committee Member: Robert X. Black. Part of the SMARTech Electronic Thesis and Dissertation Collection.

This research considers human impacts on three components of biodiversity (composition, spatial structure and function). Given the relict character and unusual biogeochemical balance of tropical montane cloud forests in Mexico, logging poses a pressing threat to their survival. Specifically, this thesis explores the effect of selective logging and above-ground secondary succession on the biogeochemical cycling and soil macroinvertebrate community in a cloud forest in Oaxaca, Mexico. The research investigates: (1) whether the above-ground chain of successional changes in tree dominance, litterfall, litter diversity and soil microenvironmental conditions are coupled with a below-ground succession of soil nutrient availability and macroinvertebrate communities, (2) the role of spatial structuring of environmental conditions and litter resources as determinates of the nutrient availability and macroinvertebrate taxa abundance, (3) the implications of successional changes for decomposition and (4) whether the local influence of single trees explains the spatial structure of macroinvertebrate communities in late successional forests. The work was carried out in three chronosequences (c.15, 45, 75 and 100 year-old stages) of high altitude (1500-2000m) tropical montane cloud forest, two recently logged sites and two pristine sites. the macroinvertebrates in the litter and mineral soil were hand sorted from monoliths. Parametric statistics and canonical correspondance analysis were used to determine mean successional trends, and Spatial Analysis by Distance Indices and geostatistical methods were used in combination to determine spatial patterns. Two decompositional experiments were performed to explore the relationship between decompositional rate, litter quality and macroinvertebrate community higher taxa composition in different successional stages and under the canopy of different tree species. The research showed that: 1. The macroinvertebrate community composition in both recently logged sites and pristine forests were distinct compared to secondary successional stages. A decrease in soil temperature and nutrient availablity but increase in litter diversity and soil organic matter recorded through succession were accompanied by an increase in the number of macroinvertebrate taxa in the soil. For exampl, Collembola were most abundant in recently logged sites and earthworms (Megascolecidae) were almost excluvely found in pristine forests. 2. The oldest secondary forest (100 year-old) showed the highest frequency of aggregation in the abundance of individual macroinvertebrate taxa, and the highest and most uniform value of Shannon's diversity. This suggests that high levels of diversity in litter resources and soil chemistry in late succession are associated with complex spatial structuring of highly diverse macroinvertebrate communities. 3. The leaves of a late successional species (Persea americana)decomposed at a slightly slower rate than an early successional species (Pinus chiapensis) in all successional stages, yet the number and Shannon's diversity of macroinvertebrate taxa that invaded decomposing P.Americana leaves was consistently higher. The preference of macroinvertebrate taxa for the late-successional leaves was ultimately explained by differences in leaf quality during decomposition. P.americana leaves had higher concentrations of cations throughout decomposition and their concentration of lignin and nitrogen became higher. 4. In the 100-year-old forest, the effect of seasonal variation on soil microenvironmental conditions and litter availability was different under the canopy of different tree species. Furthermore, the chemical evolution of the same leaf type (e.g. Oreopanax xalapensis) was differentwhen decomposing under different canopies. The highly diverse and spatially complex macroinvertebrate community found in late succession (and experimental litter) was largely explained by the interactive effects of seasonal variation, tree species, litter quality and availability of the decomposing leaf type. The results provide the first analysis of the relationship between soil biodiversity and the tight biogeochemical cycling in this relict ecosystem type. Overall the results indicate that mature cloud forests sustain a diverse and spatially heterogenous macroinvertebrate community. The compositional and spatial components of soil biodiversity are compromised by logging and full recovery may take mopre than 100 years.

Tropical forests play a key role in determining the global carbon-climate feedback in the 21st century. Changes in rainforest growth and mortality rates, especially in the deep and least perturbed forest areas, have been consistently observed across global tropics in recent decades. Understanding the underlying causes of these changes, especially their links to the global climate change, is especially important in determining the future of the tropical rainforests in the 21st century. Previous studies have mostly focused on the potential influences from elevated atmospheric CO2 and increasing surface temperature. Because the rainforests in wet tropical region are often light limited, we explore whether cloudiness have changed, and if so, whether it is consistent with what is expected from changes in forest growth rate.

Orientador: Rafael Silva Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-25T03:36:02Z (GMT). No. of bitstreams: 1 Bittencourt_PauloRobertodeLima_M.pdf: 1342116 bytes, checksum: cc6f4db33da585ea1481e6a395573774 (MD5) Previous issue date: 2014 / Resumo: Matas nebulares montanas tropicais (MNMT) são ecossistemas frequentemente inundados por neblinas, o que influencia quase todos os aspectos de seu funcionamento. MNMTs são extremamente importantes devido aos serviços ecossistêmicos que provêm, principalmente hidrológicos, e devido a sua alta biodiversidade. Com mudanças climáticas e de uso de terra já acontencendo há urgência em compreender o funcionamento de MNMTs para o desenvolvimento de estratégias de conservação e restauração. O objetivo deste trabalho é analisar e quantificar os efeitos da neblina no microclima e funcionamento foliar de MNMTs. Medimos a ocorrência de neblina, variáveis microclimáticas, parâmetros fotossintéticos e usamos uma nova metodologia para medir a capacidade de absorção foliar de água de cinco espécies abundantes de uma MNMT na região de Campos do Jordão, Brasil. Utilizamos esses dados para estimar os efeitos da neblina na disponibilidade hídrica, na demanda de água da atmosfera, na fotossíntese potencial, na absorção foliar de água e no balanço térmico foliar de MNMTs. A neblina teve um forte efeito no aumento da disponibilidade hídrica do solo e na redução da demanda atmosférica de água. A neblina apresentou um efeito negligível na redução da fotossíntese potencial das espécies estudadas. Nós apresentamos, pela primeira vez, estimativas do efeito da neblina no balanço térmico foliar mostrando que ela possui um importante papel em amenizar as temperaturas foliares médias durante o dia, reduzindo-as em 0.5oC por cada hora de ocorrência de neblina. Nós encontramos que a absorção foliar de água constituí uma fonte importante de água para as espécies estudadas, com a neblina noturna possuindo o potencial de reidratar as folhas de duas das espécies estudadas das suas condições mais secas até hidratação total em mais de 50% das noites. Diferenças na capacidade de absorção foliar de água das espécies estudadas sugere que a absorção foliar é um nicho importante de recursos com o potencial de selecionar características foliares relacionadas à eficiência de absorção foliar de água em espécies de MNMTs / Abstract: Tropical montane cloud forests (TMCFs) are ecosystem with frequent fog immersion influencing almost all aspects of its functioning.TMCFs are extremely important both due to the ecosystem services it provides, particularly hydrologically, and because of its high biodiversity. With climate and land use changes already happening there is urgency on understanding TMCFs functioning to devise conservation and restoration strategies. The objective of this work is to analyze and quantify fog effects on the microclimate and leaf functioning of TMCFs. We measured fog occurrence, microclimatic variables, photosynthetic parameters and used a new methodology to measure foliar water uptake capacity of five abundant TMCFs tree species in the region of Campos do Jordão, Brazil, We used these data to estimate fog effects on water availability, atmospheric water demand, potential photosynthesis, leaf water uptake and leaf thermal balance of TMCF. Fog had a pronounced effect on increasing soil water availability and reducing atmospheric water demand. Fog had a negligible effect on reducing potential photosynthesis of the studied species. We provide for the first time estimates of fog effects on leaf thermal balance showing it has an important effect on buffering mean daytime leaf temperatures by reducing it 0.5oC for each hour of fog occurence. We found that foliar uptake of fog water constitutes an important water source for the studied species, with nocturnal fog having the potential to rehydrate leaves of two of the studied species from its driest conditions to fully rehydration more than 50% of the nights. Differences in foliar water uptake capacity in the studied species suggests leaf water uptake is an important resource niche with potential of selecting leaf water uptake related traits in TMCFs species / Mestrado / Ecologia / Mestre em Ecologia

abstract: The Dhofar Cloud Forest is one of the most diverse ecosystems on the Arabian Peninsula. As part of the South Arabian Cloud Forest that extends from southern Oman to Yemen, the cloud forest is an important center of endemism and provides valuable ecosystem services to those living in the region. There have been various claims made about the health of the cloud forest and its surrounding region, the most prominent of which are: 1) variability of the Indian Summer Monsoon threatens long-term vegetation health, and 2) human encroachment is causing deforestation and land degradation. This dissertation uses three independent studies to test these claims and bring new insight about the biodiversity of the cloud forest. Evidence is presented that shows that the vegetation dynamics of the cloud forest are resilient to most of the variability in the monsoon. Much of the biodiversity in the cloud forest is dominated by a few species with high abundance and a moderate number of species at low abundance. The characteristic tree species include Anogeissus dhofarica and Commiphora spp. These species tend to dominate the forested regions of the study area. Grasslands are dominated by species associated with overgrazing (Calotropis procera and Solanum incanum). Analysis from a land cover study conducted between 1988 and 2013 shows that deforestation has occurred to approximately 8% of the study area and decreased vegetation fractions are found throughout the region. Areas around the city of Salalah, located close to the cloud forest, show widespread degradation in the 21st century based on an NDVI time series analysis. It is concluded that humans are the primary driver of environmental change. Much of this change is tied to national policies and development priorities implemented after the Dhofar War in the 1970’s. / Dissertation/Thesis / Doctoral Dissertation Geography 2015

Submitted by Roberta Marotti Martelletti Grillo null (robs_grillo@hotmail.com) on 2017-01-18T16:52:31Z No. of bitstreams: 1 DISSERTAÇAO FINALROBERTA GRILLO IMPR.pdf: 4057406 bytes, checksum: 6abc4cf8997545b604539c14ec124fb5 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-01-20T19:46:33Z (GMT) No. of bitstreams: 1 grillo_rmm_me_rcla.pdf: 4057406 bytes, checksum: 6abc4cf8997545b604539c14ec124fb5 (MD5) / Made available in DSpace on 2017-01-20T19:46:33Z (GMT). No. of bitstreams: 1 grillo_rmm_me_rcla.pdf: 4057406 bytes, checksum: 6abc4cf8997545b604539c14ec124fb5 (MD5) Previous issue date: 2016-09-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A Floresta Atlântica compreende a segunda maior floresta pluvial tropical do continente americano; entretanto, a devastação excessiva somada à elevada taxa de endemismo encontrada nesse ambiente a posicionou entre os cinco hotspots mais importantes do mundo. No sudeste do Brasil, a heterogeneidade florística do componente arbóreo da Floresta Atlântica tem sido relacionada a variações altitudinais e climáticas dentro de uma ampla escala geográfica e, variações microambientais, como solo e topografia, em escalas locais e regionais. O presente trabalho teve por objetivo investigar a florística e fitossociologia da comunidade arbórea de um trecho de Floresta Ombrófila Densa Atlântica (parcela S), a qual aparenta ter fisionomia altomontana típica, no entanto encontra-se aos 1.100 m de altitude, portanto, abaixo do limite mínimo estabelecido pelo IBGE para essa formação (1.500 m para a faixa latitudinal entre 16° e 24°S, em que o estudo se encontra); e comparar com uma área próxima, mas com notáveis variações fisionômicas (parcela U - Montana), presente em mesmo nível altitudinal (1.100 m). Além de verificar possíveis relações dos padrões de estrutura, composição e riqueza de espécies da comunidade com fatores edáficos, topográficos e de serapilheira, estabelecendo comparações entre as áreas, visando responder as seguintes questões: Em escala local, ocorrem diferenças significativas na composição, estrutura e riqueza de espécies entre os blocos que representam a parcela S? E em relação aos blocos da parcela U (Montana)? Caso ocorram, a topografia, o solo e/ou serapilheira explicam essas variações? Para tanto, em cada área foram implantadas quatro blocos amostrais de 50 x 50 metros, subdivididos em 10 x 10 m. As parcelas localizam-se no Parque Estadual da Serra do Mar (PESM) – Núcleo Cunha, à aproximadamente 1.100 m de altitude. Todos os indivíduos arbóreos com PAP = 15 cm contidos dentro das subparcelas foram amostrados, numerados e mensurados quanto ao PAP e altura, e mapeados por meio da tomada das medidas x e y dentro das subparcelas. As coletas foram identificadas, herborizadas e guardadas junto ao acervo do Herbário HRCB e a listagem do material seguiu a classificação do APG III. Em todas as subparcelas foram coletadas: amostras de solo através de tradagens para análise físico-química e, medida a porcentagem de inclinação do terreno com o auxílio do hipsômetro digital. Para análise da serapilheira, foram coletadas três amostras em cada uma das 40 subparcelas sorteadas, totalizando 120 amostras por área (S e U). As amostras foram constituídas pela serapilheira acumulada sobre o solo, e os parâmetros avaliados foram: peso úmido, peso seco e espessura. As análises fitossociológicas foram realizadas no software FITOPAC 2 para o componente arbóreo de cada parcela e para cada bloco amostral (0,25 ha). Diferenças entre os descritores de serapilheira, solo e topografia foram verificadas pela análise ANOVA baseada em aleatorização. A parcela S apresentou 2.183 indivíduos vivos e 340 mortos em pé, representados por 141 espécies pertencentes a 44 famílias. As famílias mais ricas foram Myrtaceae, Lauraceae e Aquifoliaceae, e as espécies com maior VI foram Pimenta pseudocayorphyllus, Cyathea phalerata e Byrsonima cf. ligustrifolia. Em relação à estrutura, a parcela S apresentou área basal de 30,15 m², diâmetro médio de 11,48 + 6,62 cm e altura média de 8,45 + 3 m. Já a parcela U apresentou 2.092 indivíduos vivos e 139 mortos em pé, representados por 134 espécies pertencentes a 38 famílias. As famílias mais ricas foram Myrtaceae, Lauraceae e Rubiaceae, e as espécies com maior VI foram Chrysophyllum viride, Guapira opposita e Cryptocarya botelhensis. Em relação à estrutura, a parcela U apresentou área basal de 46,20 m², diâmetro médio de 12,7 + 0,4 cm e altura média de 10 + 0,5. As fisionomias U e S apresentaram diferenças significativas para altura média, área basal e número de indivíduos mortos. Em relação à serapilheira, houve diferença significativa entre as parcelas apenas para espessura da serapilheira. Para os parâmetros edáficos houve diferença entre as áreas S e U para argila, areia, silte, P, K, H+Al, Al, SB, CTC, V% e declividade. O presente estudo apresentou resultados corroborando que os trechos selecionados numa mesma altitude se tratam de fitofisionomias distintas em uma escala local. Comparando com outras áreas de altitude, podemos confirmar diagnóstico prévio realizado para a parcela S como fisionomia altomontana. Os resultados apresentam diferenças na composição e riqueza de espécies em escala local, sendo relacionadas em parte às variáveis edáficas e topográficas que variam em curtas distâncias, colaborando para a heterogeneidade ambiental em microescala. Observamos que ainda são necessários mais estudos em diferentes escalas além da combinação de outros fatores ambientais a fim de entender quais outros parâmetros estariam influenciando nos padrões encontrados. / The Atlantic forest is the second largest tropical rainforest of the American continent, however excessive devastation added to the high endemism rate in this environment has placed it among the five most significant hotspots in the world. In southeast Brazil, the floristic diversity of the arboreal component in the Atlantic forest has been related to variations among climate and altitude, within a wide geographic scale, as well as microenvironment variations, such as soil and topography, in local and regional scales. This study aims to investigate the floristic and phytosociology of the arboreal community in a section of the upper montane rainforest in the Atlantic domain (S portion) and compare it with a nearby area, which shows remarkable physiognomy variations (montane) and present at the same altitudinal level (U portion). Besides checking possible links between the structure patterns, composition and richness of the community species with edaphic factors, topographic and litter, stablishing comparisons with the montane area, this study aims to answer the following questions: In local scale, do significant differences occur in composition, structure and richness of species in the S portion in comparison to the montane area? In case it occurs, do topography, soil and/or litter explain these variations? Therefore, in each area four 50 x 50 meter sample blocks were implanted and subdivided into 10 x 10 m. The portions are located at the Serra do Mar State Park (PESM) – Cunha Centre, at the altitude of approximately 1.100 m. Every tree with PAP=15 cm within the subplots was sampled, numbered and measured as to PAP and height, mapped by the x and y measurements within the subplots. The samples were identified, herborized and stored with the Herbarium HRCB collections, in which the material listing followed the APG III classification. Regarding the litter, three samples were collected in each of the 40 randomly selected subplot, accounting 120 samples per portion (S and U). The samples were formed by accumulated litter on the soil at the beginning of the rainy season of 2015. The phytosociological analysis were performed by FITOPAC 2 software for the arboreal content of each portion and for each sample block (0,25 hectares). The differences between the litter descriptors, soil and topography were checked by ANOVA analysis, based on randomization. The S portion showed 2.183 living individuals and 340 dead standing up, represented by 141 species that belong to 44 different families. The richest families were Myrtaceae, Lauraceae and Aquifoliaceae and the species with the highest VI were Pimenta pseudocayorphyllus, Cyathea phalerata and Byrsonima cf. ligustrifolia. Regarding structure, the S portion presented basal area of 20,15 m2, average diameter of 11,48 + 6,62 cm and average height of 8,45 + 3 m. The U portion presented 2.092 living individuals and 139 dead standing up, represented by 134 species that belong to 38 different families. The richest families were Myrtaceae, Lauraceae and Rubiaceae and the species with the highest VI were Chrysophyllum viride, Guapira opposita e Cryptocarya botelhensis. Regarding structure, the U portion presented basal area of 46,20 m2, average diameter of 12,7 + 0,4 cm and average height of 10 + 0,5 m. The S and U portions presented significant physiognomy differences in regard to average height, basal area and number of dead individuals. In relation to the litter, there was significant difference between the portions only regarding accumulation of litter. For edaphic parameters, there were differences between the S and U portion for clay, sand, silt, P, K, H+Al, Al, SB, CTC, V% and slope. The results of this study indicate that the investigated S and U portions, which were at the same altitude, show distinct phytophisionomies on a local scale. Compared to other areas of altitude, the pre-diagnosis of the S portion as an upper montane physiognomy can be confirmed. The results show differences in composition and richness of species in local scale, related in part to edaphic and topographic variations that vary in short distances, contributing to the environmental diversity in microscale. We note that more studies are still needed on different scales in order to understand which other parameters would be influencing the discovered patterns.

The thesis deals with the possible use of optical data for modeling forest area compared with utilization of airborne laser scanning data. At first these two datasets are compared and causes of differences are explained. Then canopy height models are made and object-oriented classification is applied for separation of vegetation stands. Methodical procedure is suggested for delineation and detection individual trees in forest. Then their height is detected. There are summarized and other possibilities for improvement in detection and delineation of trees. The results show that optical data with resolution about 25 cm are suitable for dermining the characteristics of the forest stands up to individual tree level. The outputs of this research can be used for forest inventory. Key words: aerial imagery, image matching, laser scanning, point cloud, forest inventory

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

As comunidades florestais periféricas às florestas que recobrem o sopé e as médias encostas da Serra do Mar apresentam uma convergência de fisionomias e aspectos xeromórficos, sustentada por floras que estão relacionadas quanto às suas origens. Como estas semelhanças podem indicar condições ecológicas similares, o trabalho investigou qualitativa e quantitativamente se as semelhanças fisionômicas, entre a Floresta do Topo dos Morros da Serra do Mar e a Floresta Seca de Restinga no Estado de São Paulo, são acompanhadas por semelhanças florísticas e estruturais. Esta investigação teve como objetivos: caracterizar e comparar, em termos fitossociológicos, as florestas secas de restinga e as florestas do topo das escarpas atlânticas; e analisar as relações entre possíveis padrões florísticos e estruturais do componente arbóreo destas florestas e condições edáficas e climáticas de seus ambientes. A amostragem foi realizada a partir de 10 parcelas de 10 m X 10 m em cada uma das seis áreas de estudo. Para o topo da Serra do Mar considerou-se a floresta nas seguintes Unidades de Conservação: Estação Biológica de Boracéia; Núcleo Curucutu do PESM e Parque Estadual Intervales. Para a floresta seca de restinga, as áreas de estudo foram: Núcleo Picinguaba do PESM, Estação Ecológica Juréia-Itatins e Parque Estadual Ilha do Cardoso. Através da descrição fitossociológica das comunidades e de técnicas de análise multivariada para classificação e ordenação, observou-se que as áreas de floresta do topo das encostas são pouco similares florística e estruturalmente em relação às florestas secas de restinga. As pequenas semelhanças entre as florestas estudadas dizem respeito às espécies de grande plasticidade ecológica e que, por isso, possuem ampla distribuição geográfica. As diferenças florísticas e estruturais foram determinadas pelas espécies oriundas das florestas que recobrem as encostas da Serra do Mar, sendo que nehuma das espécies consideradas importantes é endêmica de um dos tipos florestais, não sustentando, assim, a convergência ecológica. / Plant communities at the periphery of the Atlantic rainforest that recover the lower and middle slopes of Serra do Mar presents a convergence of physiognomy and xeromorphycs aspects, supported by floras that are related on its origins. As these convergence can indicate similar ecological conditions, this present work investigated if the similarities between Upper Slope Forest and the Restinga Forest in the State of São Paulo, Brazil, are followed by floristic and structural similarities. This inquiry had two objectives: characterize and compare the Upper Slope Forest and the Restinga Forest in its phytosociological aspects; analyze the relationships between edaphic and climatic conditions and floristic and structural patterns of the arboreal component of these forests. To characterize the Upper Slope Forest was considered forests in the following Conservation Units: Estação Biológica de Boracéia, Núcleo Curucutu do Parque Estadual da Serra do Mar and Parque Estadual Intervales; and to characterize the Restinga Forest the study areas were in the following Conservation Units: Núcleo Picinguaba do PESM, Estação Ecológica Juréia-Itatins and Parque Estadual Ilha do Cardoso. For structural vegetation analysis, were used 10 plots of 10 x 10 m in each area. The phytosociological description and multivaried analysis of classification and ordination showed that areas of Upper Slope Forest and Restinga Forest have low similarity. The resemblances are based on occurrence of broad ecological plasticity species and, therefore, of wide distribution. On the other hand, the floristic and structural heterogeneity is consequence of the predominance, in each forests type, of different species from the Atlantic rainforest that recover the lower and middle slopes of Serra do Mar, not supporting the ecological convergence hypothesis.