O presente trabalho teve por objetivo avaliar o efeito de três ecossistemas sobre, a ocorrência de fungos rizosféricos, endofíticos e epifíticos. As áreas de estudo estão localizadas em uma propriedade rural, situada na cidade de Venâncio Aires, RS. Os fungos endofíticos e epifíticos foram isolados de amostras de raízes de guajuvira, (Patagonula americana L.), coletadas na mata (área 1), de uva-do-japão (Hovenia dulcis Thunb.), na área intermediária (área 2) e de fumo ou de milho, na lavoura (área 3) e, os fungos rizosféricos isolados de solo coletado junto as raízes dos vegetais citados. As amostras foram coletadas nos meses de janeiro, maio, setembro e novembro de 2004 e 2005. Os fungos foram identificados segundo características morfológicas com auxílio de chaves de identificação. As áreas 2 e 3 foram mais similares com relação aos fungos rizosféricos e epifíticos, enquanto, que, as áreas 1 e 2 foram mais similares com relação aos fungos endofíticos. A diversidade dos fungos isolados das três áreas não diferiu ao longo dos dois anos de coleta. A presença de Fusarium spp., em vegetais sem sintomas de doença indica que, as mesmas podem ser raças avirulentas ou patógenos latentes em equilíbrio com o hospedeiro e o ambiente. A presença de fungos antagonistas, principalmente Trichoderma spp. também, são responsáveis por esse equilíbrio, o qual ocorre nas três áreas. / The present paper aimed at assessing the effect of three ecosystems, on the occurrence of rhizospheric, endophytic and epiphytic fungi. The study areas are located in a farm in Venâncio Aires, Rio Grande do Sul. Samples were collected in the months of January, May, September and November 2004 and 2005. The endophytic and epiphytic fungi were isolated from samples of guajayvi roots (Patagonula americana L.), picked in the forest (area 1), of Japanese raisin tree (Hovenia dulcis Thunb.), in the intermediate area (area 2), and tobacco or corn, in the cultivated area (area 3) and rhizospheric fungi isolated from soil. The fungi were identified according to morphological characteristics, with the help of identification keys. Areas 2 and 3 were more alike concerning rhizospheric and epiphytic fungi; Areas 1 and 2, in turn, were more alike concerning endophytic fungi. The diversity of the isolated fungi from these three areas did not change during the two years of collection. The abundance of fungi with phytopathogenic potential such as the Fusarium spp. and Macrophomina phaseolina, mostly as endophytic in area 3 shows the influence of the host on them. The presence of antagonistic fungi, principally Trichoderma spp. also, are responsable for this equilibrium, which occured in the three areas.

Anthropogenic activities have increased nitrogen (N) emissions. However, higher N deposition is associated with negative fallouts in ecosystems, highlighting the necessity to define its critical load (CLO). Lichens, with their lack of roots, stomata, and cuticles, are helpful air pollution indicators and can be used to establish N CLO. Several studies report epiphytic lichens’ reaction to N deposition, but few have also focused on their recovery. In this study, I reproduced a deposition gradient to investigate epiphytic lichen biomass response to long-term N deposition. As such, whole trees were fertilized with 0.6, 6, 12.5, 25, or 50 kg N/ha/year from 2006 to 2012. In 2012, after six years of irrigation, Hypogymnia species and A. sarmentosa had altered biomass, and based on those results, a CLO below 6 kg N/ha/year is recommended for epiphytic lichens in the boreal forest. I also investigated the recovery of epiphytic lichens nine years after the simulated N deposition ceased. In 2021, a high increase in lichen biomass was recorded, suggesting that lichen growth rate is faster than previously assumed by other studies. However, biomass recovery was lower in high N treatments in Hypogymnia sp., Bryoria sp., and A. sarmentosa, suggesting those species recall the historical treatments possibly due to retained impairments. Since differences among treatments increased in the nine years after the simulated N deposition ceased, my results indicate that short-term negative effects of N deposition can have long-lasting effects on the epiphytic lichen community. Thus, I stress the importance of considering the recovery capability of different species during CLO determination to avoid underestimating the impact of N deposition.

Biologisk mångfald har en nyckelroll i välfungerande ekosystem och bevarandet av denna även i stadsmiljö blir väsentligt med tanke på den ökande urbaniseringen. Övervakning av olika slag kan ses som ett steg på vägen till ökad kunskap inom ämnet om hur den biologiska mångfalden skall skötas och stödjas. Då lavar påverkas relativt snabbt av förändringar i miljön kan dessa användas till olika typer av miljöbedömningar. Det är troligt att om lavfloran uppvisar tecken på störning är även andra arter och ekosystem negativt påverkade i mer eller mindre utsträckning. Denna studie har som utgångspunkt att jämföra epifytiska lavar i två tätorter vilka har och har haft olika förutsättningar både ur ett naturligt perspektiv – t.ex. genom olika klimat – samt från mänsklig påverkan från t.ex. andelen luftföroreningar. Orterna som valdes var Uddevalla, en tätort på Sveriges västkust, och Östersund, en stad i södra Norrlands inland. Främst fokus i jämförelsen låg på förekomsten av 13 utvalda lavarter som räknades i artantal, täckningsgrad och frekvens i brösthöjd på nord- respektive sydsida på trädslagen björk, asp och tall. Totalt undersöktes 80 träd, totalt 160 provytor, inom en tre km radie från respektive centrum. Ytterligare antecknades förekomsten av övriga lavarter utöver de utvalda arterna. Även eventuella samband mellan lavförekomst och brösthöjdsdiamer (DBH), lavförekomst och avstånd från centrum samt lavförekomst på nord- jämfört med sydsidan undersöktes. Resultatet visade att Östersund hade större förekomst av de utvalda epifytiska lavarterna, högst total av upptäckta arter (utvalda + övriga), högre frekvens samt högre täckningsgrad. Alla 13 utvalda arter förekom i varierande utsträckning i Östersund jämfört med att endast åtta av dessa arter återfanns i Uddevalla. Däremot uppvisade Uddevalla högre andel övriga lavarter (17 jämfört med 12 i Östersund) samt något större individstorlek. Föroreningskänsliga, hängande busklavar såsom tagellav (Bryoria ssp) och luddig skägglav (Usnea hirta) saknades i Uddevalla men förekom i relativt stor utsträckning i Östersund. Mindre känsliga arter såsom flarnlav (Hypocenomyce scalaris) och olika mjöllavar (Lepraria ssp) förekom istället i högre utsträckning i Uddevalla. Inga direkta sambands sågs gällande lavförekomst i förhållande till trädets diameter eller avstånd från centrum. Östersund hade störst andel lavar inom en km från busstationen medan Uddevalla uppvisade lägst värden närmare busstationen.  Provträdens nordsida hade generellt en högre täckningsgrad där skillnaden mellan nord- och sydsida var betydligt större i Östersund, speciellt på tall.   Orsakerna till skillnaderna mellan tätorterna har inte undersökts vidare, men en orsak skulle kunna vara att Sveriges västkust historisk sett varit utsatt för mer luftföroreningar i form av svaveldioxid (SO2) även från andra länder i Europa (Helmersson 2015) – troligtvis i högre grad än norra Sveriges inland – vilket påverkat lavfloran negativt. Orsakerna till skillnaderna mellan tätorterna kan vara objekt för vidare studier. Studien skulle även kunna vara ett första steg för eventuell fortsatt övervakning i tätorterna för att kunna se skillnader i artsammansättning och täckningsgrad över tid. / Biodiversity has a key role in well-functioning ecosystems, hence the conservation of it in urban areas becomes essential with the increasing urbanization. Monitoring biodiversity can be seen as a way to increase knowledge within the area of how biodiversity should be kept and supported. As lichen respond relatively fast to changes in the environment, these can be used for different types of environmental assessments. It’s likely that if the lichen shows signs of disturbance, other species and ecosystems will also be negatively affected to an extent. This study is based on a comparison of epiphytic lichen in two urban areas which have been affected by different conditions both from a natural perspective – e.g. through different climates – and from human influences from e.g. amount of air pollutants. The areas that were chosen were Uddevalla, a town on the Swedish west coast, and Östersund, a town in the middle of Sweden. The main focus in the comparison was the presence of 13 selected lichen, which were counted in number of species, degree of coverage and species frequency. Measurements were done on the north and south side of tree trunks in chest height, on the tree species birch, aspen and pine. A total of 80 trees – a total of 160 sample areas – were examined, within a three km radius from each town center. The presence of other species of lichen besides the selected species was noted. Analyses regarding possible correlations between lichen occurrence and the trees diameter at breast height (DBH), lichen occurrence and distance from the town center and lichen occurrence on the tree’s north side compared to the south was also done. The results showed that Östersund had more of the study’s selected epiphytic lichens, the highest total of observed species (selected + others), higher frequency and higher degree of coverage. All 13 selected species occurred in varying degree in Östersund, compared with only eight of these species being found in Uddevalla. On the other hand, Uddevalla showed a higher proportion of other lichens (17 compared with 12 in Östersund) and a slightly larger size of each individual lichen. More sensitive, hanging lichen such as Bryoria ssp and Usnea hirta were missing in Uddevalla but occurred in larger extent in Östersund. Less sensitive species such as Hypocenomyce scalaris and Lepraria ssp occurred more often in Uddevalla. No obvious connections were seen regarding lichen occurrence in relation to the tree's diameter or distance from the town centers. Östersund had the largest proportion of lichens within one km from the bus station, while Uddevalla showed the lowest values ​​closer to the bus station. The north sides of the sample trees generally had a higher degree of lichen coverage and the difference between the north and south sides was significantly greater in Östersund, especially on pine. The reasons for the differences between the two towns have not been investigated further, though one of the reasons why Östersund had more lichen may be that the Swedish west coast historically has been affected more by air pollutants such as SO2 also from other countries in Europe (Helmersson 2015) – probably to a higher degree than the northern parts of Sweden – which have had a negative effect on lichens. The reasons for the differences between the urban areas may be objects for further studies. The study could also be seen as a first step for continued monitoring in the urban areas over time / <p>2021-06-04</p>

The Swedish forestry and the use of clearcutting models has resulted in great losses of older forests in Sweden, resulting in several species being affected negatively. Hair lichens are important organisms that are providing several ecological functions in forest ecosystems and are declining due to being associated with older forests with high continuity. This study investigates the occurrence and dispersal ability of the genus Alectoria, Bryoria and Usnea between older forests and young secondary forests in three different areas in Storuman municipality, Västerbotten county. Bryoria were found on all trees in all forest patches, both in the old and young forest patches, while Alectoria had much lower occurrence in the young secondary forest. Usnea had no observed pattern in occurrence between the different areas. The average length of the lichens, here used as a proxy for lichen biomass, showed a statistical difference in biomass between areas for genera Bryoria and Usnea. The genera Alectoria showed a difference in biomass between areas, distance to closest older forest and the interaction between these two. Therefore, this study suggests that Alectoria is limited in dispersal in these areas. Some of the results could be explained by distribution and dispersal ability of the studied genera. To further evaluate the differences seen in occurrence and biomass between the genera and the different areas more studies are needed. This could provide important information for sustainable forestry that favors lichens and benefits reindeer husbandry.

O metabolismo ácido das crassuláceas (CAM) representa uma importante via de assimilação de carbono fotossintético, caracterizado pela fixação do CO2 atmosférico durante o período da noite, por meio da enzima fosfoenolpiruvato carboxilase (PEPC) e pelo acúmulo noturno de ácidos orgânicos. Nesse tipo de fotossíntese, os estômatos permanecem fechados durante a maior parte do dia e, consequentemente, propicia uma maior eficiência no uso da água quando comparado com plantas C3. Essa adaptação ecofisiológica permite às espécies CAM suportar alterações frequentes na disponibilidade de água no meio ambiente. Guzmania monostachia é uma bromélia epífita com tanque que apresenta a capacidade de alterar seu metabolismo fotossintético, passando de C3 a CAM, em resposta a condições ambientais estressantes, constituindo-se, portanto, num interessante modelo de estudo sobre plasticidade fisiológica. Algumas pesquisas anteriores do nosso laboratório mostraram que diferentes regiões foliares de G. monostachia podem desempenhar funções distintas em resposta à escassez hídrica. Foi visto que a expressão do CAM ocorreu com intensidades diferentes ao longo do comprimento foliar, sendo mais pronunciada na região apical. Um possível direcionamento da água da região basal para apical foi hipotetizado ocorrer, de forma que mesmo em situações de curta restrição hídrica (7 dias), a quantidade de água nos tecidos da porção apical permaneceu praticamente constante. Levando em consideração esses resultados prévios, a presente pesquisa teve como objetivo principal caracterizar o padrão de expressão do CAM nas folhas de diferentes estágios ontogenéticos (folhas jovens, intermediárias e maduras), bem como em suas porções, relacionando com as possíveis variações no estado hídrico durante a imposição da restrição no fornecimento de água por um período de até oito dias. E investigar se as variações do potencial hídrico foliar seriam decorrentes de alterações no acúmulo de ácidos orgânicos e/ou açúcares solúveis nas diferentes porções foliares e nas folhas em diferentes estágios do desenvolvimento. Para tanto, plantas de G. monostachia tiveram a rega suspensa durante oito dias e, posteriormente, elas foram reidratadas por dois dias consecutivos. As coletas foram realizadas nas seguintes condições experimentais: 1) sem suspensão de rega, ou seja, as plantas foram mantidas bem hidratadas (controle), 2) com suspenção de rega por 1, 4 e 8 dias e 3) com retorno à rega após o período de seca (2 dias de reidratação). Amostras de folhas em diferentes fases de desenvolvimento (jovens, intermediárias e adultas) foram divididas em três porções ápice, mediana e base para determinação do potencial hídrico, conteúdo relativo de água e abertura do poro estomático, além dos ensaios da atividade enzimática da PEPC, quantificação de açúcares solúveis e do acúmulo noturno de ácido málico. Os resultados demonstraram que as regiões apical e mediana de todas as folhas pertencentes aos diferentes estágios de desenvolvimento da roseta expressaram o CAM, quando submetidas a uma situação de restrição hídrica por no mínimo quatro dias. A porção apical foi a que apresentou os parâmetros indicativos desse metabolismo de forma mais intensa. Além disso, com a imposição à seca, a transição entre o metabolismo C3 para o CAM clássico parece ocorrer até o quarto dia de suspenção de rega, com abertura dos estômatos predominantemente no período da noite e, ao estender o período de escassez hídrica para oito dias, foi possível observar a transição para o CAM do tipo idling, isto é, com fechamento estomático diuturnamente. Observou-se também, uma redução gradual do potencial hídrico ao longo do período de exposição à seca, principalmente no ápice de folhas de diferentes estágios ontogenéticos. Além disso, o ápice das folhas de todos os grupos ontogenéticos e, em especial, as folhas jovens (incluindo as porções mediana e basal) foram os que não apresentaram redução do conteúdo hídrico durante o tratamento de seca por oito dias. Entretanto, a partição de açúcares solúveis foi alterada, de forma que a porção da basal, a qual inicialmente mantinha as maiores quantidades de carboidratos, apresentou reduções significativas no conteúdo de frutose e glicose com o prolongamento da seca para 8 dias. Já a porção apical, teve um comportamento inverso. Esses resultados sugerem que o tratamento de déficit hídrico pode desencadear um ajuste osmótico tanto nos diferentes grupos foliares da roseta quanto no limbo foliar, direcionando, preferencialmente, o transporte da água às folhas jovens e ao ápice das folhas de diferentes idades. Com a retomada da rega, após um período de déficit hídrico de oito dias, notou-se que apenas dois dias de rega normalizada foram suficientes para que o conteúdo hídrico fosse totalmente recuperado. No entanto, a partição de açúcares solúveis entre as folhas da roseta, não apresentou um padrão semelhante ao controle (plantas bem hidratadas). O metabolismo fotossintético também não foi revertido de CAM para C3, sugerindo ser necessário um período maior de reabastecimento de água no tanque / Crassulacean acid metabolism (CAM) is a photosynthetic CO2 fixation pathway that evolved in some plants. It is characterized by the fixation of atmospheric CO2 during the night, by the enzyme phosphoenolpyruvate carboxylase (PEPC) and nocturnal organic acid accumulation. In a plant using CAM, the water use efficiency is maximized because the stomata remain closed during daytime and open at night when the relative humidity of the air is higher. Guzmania monostachia, an epiphytic bromeliad, is an interesting plant model because it presents the ability to change its photosynthetic metabolism, from C3 to CAM, in response to stressful environmental conditions. Previously studies demonstrated that different leaf regions of G. monostachia performed distinct functions in response to water stress. In addition, CAM expression was more pronounced in the apical region. Even in situations of water restriction for 7 days, the amount of water in the tissues of the apical portion remained almost constant. Then, the present study hypothesized that the water may be transported from the base to the apex. The present study aimed at characterize the CAM expression pattern in leaf blade and among different foliar groups (younger, intermediate and older leaves), relating them to variations in water status during suspension irrigation for a period of up to eight days. In addition, the present study investigated if the possible variations of the water leaf potential would be due to changes in the accumulation of organic acids and/or soluble sugars in different leaf portions at different foliar ontogenetic groups. Three experimental conditions were carried out: 1) well-watered condition (control), 2) under suspension irrigation (for 1, 4 and 8 days) and 3) rewatered treatment, after drought period (watered daily for two days). Leaf samples of different foliar groups (younger, intermediate and older) were divided into three portions (apex, middle and base) for determination of water potential, relative water content, stomatal aperture, PEPC activity, quantification of soluble sugars and nocturnal malate accumulation. Results indicated that apical and middle portions of all the leaves belonging to different foliar groups of the rosette expressed CAM when watering was suspended for at least four days. The apical portion displayed the most intense parameters indicative of CAM expression. In addition, with drought imposition, the transition from C3 metabolism to classic CAM appears to occur up to the fourth day of irrigation suspension, with stomatal aperture during nighttime. When extending the period of water shortage for eight days, the establishment of a typical CAM-idling pathway, with stomatal closure during day and night, was verified It was also observed a gradual reduction of water potential, during the period of exposure to drought, mainly at the apical of leaves of different foliar groups. At the apex of all foliar ontogenetic groups, and especially the younger leaves (including the middle and basal portions) were those that did not present reduction of water content during the drought treatment for eight days. However, the partition of soluble sugars was altered, so that the basal portion, which initially maintained the highest carbohydrate levels, showed significant reductions in the fructose and glucose content with prolongation of the drought for 8 days. The apical portion had the opposite behavior. These results suggest that drought treatment can trigger an osmotic adjustment both in the different leaf ontogenetic groups of the rosette and of the leaf blade. In this way, the water transport preferably favors the younger leaves and the apical of the different leaf developmental stages. After a period of water deficit, the plants were rehydrated (for two days) and the water content was fully recovered. However, the partition of soluble sugars along the rosette leaves did not present a pattern similar to that observed before of the beginning of the hydration interruption. The photosynthetic metabolism was also not reversed from the CAM to C3, suggesting that a longer tank replenishment period is necessary

Submitted by Liliane Ferreira (ljuvencia30@gmail.com) on 2018-04-04T14:02:36Z No. of bitstreams: 2 Tese - Jaques Everton Zanon - 2018.pdf: 3230898 bytes, checksum: 7e20d6f4c53febb70d99701805d33565 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-04-05T12:50:16Z (GMT) No. of bitstreams: 2 Tese - Jaques Everton Zanon - 2018.pdf: 3230898 bytes, checksum: 7e20d6f4c53febb70d99701805d33565 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-04-05T12:50:16Z (GMT). No. of bitstreams: 2 Tese - Jaques Everton Zanon - 2018.pdf: 3230898 bytes, checksum: 7e20d6f4c53febb70d99701805d33565 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Population synchrony occurs when abundance of different local populations increase and decrease simultaneously along time. In terms of other characteristics that can be measured in ecosystems, such as biomass and nutrient contents, intrinsic and extrinsic processes have also been used to explain synchronic variation patterns. Synchrony may clarify whether regional processes are more important than local processes. This study used epiphytic biomass data (chlorophyll-a) from eight locations collected in a floodplain through 11 years. The goal was to estimate epiphytic biomass synchrony. We anticipated that high synchrony levels would be consistent with the strong impact of floods, which affect different floodplain habitats simultaneously. This is equivalent to the Moran effect. In contrast, low synchrony levels would be consistent with the hypothesis that high environmental heterogeneity of floodplains hampers synchrony. Our results indicated low synchrony and its variation was not correlated with geographic or environmental distances and neither with environmental synchrony. Also, regression models demonstrated low predictive power of local environmental variables in predicting biomass variation in the different sites. In addition, we performed a meta-analysis that confirms the generality of our findings. In conclusion, these results challenge the efficiency of epiphytic biomass as an ecological indicator, at least in floodplain system. / Populações locais, mesmo quando distribuídas em amplas extensões espaciais, variam de forma sincrônica, ou seja, suas abundâncias aumentam e diminuem simultaneamente ao longo do tempo. Em termos de outras características que podem ser mensuradas em ecossistemas, tais como, biomassa e teores de nutrientes, os conceitos de coerência temporal, forças intrínsecas e extrínsecas também têm sido utilizadas para explicar padrões sincrônicos de variação. A magnitude do fenômeno de sincronia pode elucidar se o padrão que processos extrínsecos (e.g., efeitos de fontes difusas sobre as concentrações de nutrientes) são mais importantes que processos intrínsecos (efeitos de fontes pontuais). Nesse estudo nós utilizamos dados de biomassa (clorofila a) do perifíton em 8 locais e 37 meses coletados em uma planície de inundação. O objetivo desse estudo foi de avaliar o padrão de sincronia da biomassa perifítica. Primeiro, nós conjecturamos que elevados níveis de sincronia seriam condizentes com o forte impacto das inundações que influenciam simultaneamente diferentes hábitats de uma planície de inundação, analogamente ao efeito de Moran. Por outro lado, baixos níveis de sincronia seriam condizentes com a hipótese de maior importância da heterogeneidade ambiental (ao longo do espaço), uma vez que planícies de inundação são consideradas um mosaico de manchas de habitats. Em suma nós encontramos baixos valores de sincronia. Variações na sincronia não foram correlacionadas com a distâncias geográfica e ambiental tampouco com a sincronia ambiental. Ainda a nossos modelos GLS demonstraram pouco poder preditivo do ambiente local acerca da biomassa. Como conclusão nosso estudo demonstra o baixo poder preditivo da biomassa perifítica acerca de fatores regionais e locais nos ambientes estudados.

A filosfera da Mata Atlântica é um importante nicho de colonização por micro-organismos, cuja comunidade ainda é pouco conhecida. Algumas bactérias associadas à superfície das folhas possuem habilidade de fixar nitrogênio, mineralizar substratos orgânicos e também suprir as árvores com dióxido de carbono e fatores de crescimento. Este trabalho teve como objetivo gerar informações sobre a comunidade cianobacteriana que coloniza a filosfera de algumas plantas da Mata Atlântica e investigar a comunidade diazotrófica presente nesse habitat. Um total de 40 linhagens de cianobactérias da filosfera de Merostachys neesii (bambu), Euterpe edulis (palmeira Juçara), Guapira opposita e Garcinia gardneriana foram isoladas e cultivadas. Os isolados foram caracterizados por análises morfológicas e filogenia do gene 16S RNAr. Essa abordagem permitiu a identificação de uma linhagem do gênero Nostoc, sete Desmonostoc, seis Leptolyngbya, uma Oculatella, cinco Brasilonema, uma Pleurocapsa e duas Chroococcidiopsis. Dezessete linhagens (uma Microchaetaceae, dez Nostocaceae e seis Pseudanabaenaceae) não puderam ser identificadas ao nível de gênero. Vinte e seis linhagens (24 pertencentes às ordens Nostocales e duas à Pseudanabaenales) foram caracterizadas como diazotróficas pela amplificação, sequenciamento e filogenia do gene nifH. Além disso, caracterizou-se o perfil de fixação biológica de nitrogênio da linhagem Desmonostoc sp. CENA362. Com relação ao potencial biotecnológico dessas linhagens, treze isolados foram identificados como potenciais produtores de ácido indol acético (IAA) de acordo com o teste Salkowski. Diversas linhagens apresentaram genes associados à via biossintética do inibidor de protease microviridina, sendo que três delas codificam para novas variantes. Além disso, dez linhagens foram identificadas como potenciais produtoras aeruginosina, três de cianopeptolina e três de microcistina. A comunidade bacteriana diazotrófica avaliada por pirosequenciamento do gene nifH apresentou um perfil de variação espécie-específica para Proteobacteria e uma correlação positiva entre a riqueza e a fixação biológica de nitrogênio. Neste estudo, cianobactérias que habitam a filosfera da Mata Atlântica foram isoladas estão sendo mantidas em condições de cultivo. Novos táxons foram descobertos e vários gêneros conhecidos foram descritos pela primeira vez neste hábitat, o que contribuiu para o aprimoramento da sistemática de Cyanobacteria. As linhagens em cultivo e as informações geradas sobre os seus compostos metabólitos representam uma valiosa fonte para estudos posteriores. Além disso, informações sobre a comunidade bacteriana diazotrófica da filosfera pode auxiliar no entendimento da dinâmica do nitrogênio, elemento limitante e pouco disponível na Mata Atlântica / The phyllosphere of the Atlantic Forest is an important niche for colonization by microorganisms, whose community is still little known. Some bacteria associated with leaf surfaces may possess the ability to fix nitrogen, mineralize the organic substrates and also supply the trees with carbon dioxide and growth factors. Therefore, this study aimed to generate information about cyanobacterial community that colonize the phyllosphere of some plants of the Atlantic Forest and investigated the diazotrophic community in this habitat. A total of 40 strains of Cyanobacteria from the phyllosphere of Merostachys neesii (bamboo), Euterpe edulis (Juçara palm), Garcinia gardneriana and Guapira opposita was isolated and cultivated. The isolates were characterized by morphological analyses and phylogeny of the 16S rRNA gene. This approach allowed the identification of one strain of the genus Nostoc, seven Desmonostoc, six Leptolyngbya, one Oculatella, five Brasilonema, one Pleurocapsa and two Chroococcidiopsis. Seventeen strains (one Microchaetaceae, ten Nostocaceae and six Pseudanabaenaceae) could not be identified at the genus level. Twenty-six strains (24 belonging to Nostocales and two belonging to Pseudanabaenales) were characterized as diazotrophic by amplification, sequencing and phylogeny of nifH gene. Also, it was characterized the profile of biological nitrogen fixation for the strain Desmonostoc sp. CENA362. Regarding the biotechnological potential of these strains, thirteen strains were identified as potential producers of indole acetic acid (IAA) according to Salkowski test. Several strains presented genes involved in the biosynthetic pathway of the protease inhibitor microviridin, three of them encoding putative novel variants. Moreover, ten strains were identified as potential producers of aeruginosin, three of cyanopeptolin and three of microcystin. The diazotrophic bacterial community evaluated by pyrosequencing of the nifH gene showed a profile of variation plant species-specific for Proteobacteria, and a positive correlation between richness and biological nitrogen fixation. In this study, cyanobacteria that inhabiting Brazilian Atlantic Forest phyllosphere were isolated and are been maintained in culture conditions. New taxa were discovered and several known genera were described for the first time in this habitat, which contributed to improvement of the cyanobacterial systematic. The culturable strains and the information generated about their metabolites compounds represent a valuable source for further studies. In addition, information about the diazotrophic bacterial community inhabiting the phyllosphere may help in understanding the dynamics of nitrogen, a limiting and low available element in Atlantic Forest

Globally, more than half of the world's population is living in urban areas and it is well accepted that human activities (e.g. climate warming, pollution, landscape homogenization) pose a multitude of threats to ecosystems. Largely, human-related impacts on biodiversity will hold consequences for larger ecological processes and research looking into human impacts on sensitive epiphytic lichen and moss communities is an emerging area of research. While seemingly small, lichen and moss communities exist on nearly every terrestrial ecosystem on Earth and contribute to whole-system processes (e.g. hydrology, mineral cycling, food web energetics) worldwide. To further examine human impacts on epiphytic communities, I conducted three studies examining urbanization and climate warming effects on epiphytic lichen and moss biodiversity and ecology. In the first study I revisited a historic urban lichen community study to assess how urban lichen communities have responded to regional air quality changes occurring over the last nearly two decades. I further investigated, for the first time, the biodiversity of urban tree canopy-dwelling lichen communities in a native coniferous tree species, Pseudotsuga menziesii. I found that urban parks and forested areas harbor a species rich community of lichens epiphytes. Further, I found evidence for the distinct homogenization of urban epiphytic lichen communities, suggesting that expanding beyond simplistic measures of biodiversity to consider community composition and functional biodiversity may be necessary when assessing the ecology and potential ecosystem services of epiphyte communites within urbanizing landscapes. Next, I present the first tall tree canopy study across a regional gradient of urbanization near Portland, Oregon, USA. I found that tall tree canopy epiphyte communities change dramatically along gradients of increasing urbanization, most notably by the transitioning of species functional groups from sensitive, oligotrophic species to a dominance of urban-tolerant, eutrophic species. The implications these dramatic shifts in species composition have on essential PNW ecosystem processes, like N-fixation and canopy microclimate regulation, is still not well understood and is difficult to formally evaluate. However, I find strong evidence that native conifer trees in urban areas may provide a diversity of essential ecosystem services, including providing stratified habitat for epiphyte communities and their associated micro arthropod communities and the scavenging of atmospherically deposited nutrients. Future work is needed to understand how losses in canopy N fixation and species with large biomass (both lichens and bryophytes) will affect nutrient and hydrologic cycling in the PNW region, which continue to undergo rapid growth and urbanization. The final chapter investigates the impacts of passive warming by Open Top Chambers (OTCs) in moss-dominated ecosystems located on the Western Antarctic Peninsula, an area of increasing climate warming. I compared species-specific temperature effects, moss canopy morphology, sexual reproductive effort and invertebrate communities between OTC and control moss communities for two moss species, Polytrichastrum alpinum and Sanionia uncinata, that make up over 65% of the terrestrial vegetative cover in the area. I found distinct reproductive shifts in P. alpinum under passive warming compared to controls. Moss communities under warming also had substantially larger total invertebrate communities than those in control moss communities, and invertebrate communities were significantly affected by moss species and moss reproductive effort. Further, substantial species-specific thermal differences among contiguous patches of these dominant moss species were revealed. These results suggest that continued warming will differentially impact the reproductive output of Antarctic moss species and is likely to dramatically alter terrestrial ecosystems dynamics from the bottom up. This combined work provides a diverse contribution to the field of epiphyte ecology and biology by providing new insights on how human impacts will affect epiphyte lichen and moss communities across diverse ecosystems, in light of a rapidly changing planet.

<p>This thesis examines the relative importance of local conditions, dispersal and dynamics of the trees on epiphyte distribution patterns and colonization-extinction dynamics. Study species are the mosses <i>Orthotrichum speciosum </i>and <i>O. obtusifolium</i>, and the red-listed <i>Neckera pennata</i>. The thesis also includes an attempt to parameterize a model for a lichen metapopulation (<i>Lobaria pulmonaria</i>) in a dynamic landscape, based on only presence/absence data of the epiphyte and its host trees. </p><p>The results show that epiphyte colonization of trees is affected by both local conditions, and by connectivity to occupied trees. The positive effect of connectivity, implying a restricted dispersal range, was established by both demographic and genetic studies. The important local conditions were tree diameter and vitality, and shade. Local extinctions from trees occurred among small trees with low local epiphyte abundance, but more often, were the results of tree fall.</p><p>The observed importance of connectivity on epiphyte colonization agrees with the assumptions of the classic metapopulation model. However, the classic metapopulation model assumes that the landscape is static, and that local extinctions occur for stochastic reasons. The dynamics of epiphytes are different. A new conceptual model is therefore suggested, the patch-tracking metapopulation model. It differs from the classic metapopulation model in that it includes dynamics of the patches, and in that local extinctions only occur as patches are destroyed.</p><p>Simulations of the dynamics of <i>N. pennata </i>showed that its future metapopulation size will be overestimated unless the dynamics of the trees are accounted for. The simulation results further suggest that the dynamics of <i>N. pennata </i>can be characterised by the patch-tracking metapopulation model. </p><p>The attempt to parameterize the <i>L. pulmonaria </i>metapopulation model showed that more information are required for rigorous parameterization, preferably of the past historic fire regime.</p>

This thesis examines the relative importance of local conditions, dispersal and dynamics of the trees on epiphyte distribution patterns and colonization-extinction dynamics. Study species are the mosses Orthotrichum speciosum and O. obtusifolium, and the red-listed Neckera pennata. The thesis also includes an attempt to parameterize a model for a lichen metapopulation (Lobaria pulmonaria) in a dynamic landscape, based on only presence/absence data of the epiphyte and its host trees. The results show that epiphyte colonization of trees is affected by both local conditions, and by connectivity to occupied trees. The positive effect of connectivity, implying a restricted dispersal range, was established by both demographic and genetic studies. The important local conditions were tree diameter and vitality, and shade. Local extinctions from trees occurred among small trees with low local epiphyte abundance, but more often, were the results of tree fall. The observed importance of connectivity on epiphyte colonization agrees with the assumptions of the classic metapopulation model. However, the classic metapopulation model assumes that the landscape is static, and that local extinctions occur for stochastic reasons. The dynamics of epiphytes are different. A new conceptual model is therefore suggested, the patch-tracking metapopulation model. It differs from the classic metapopulation model in that it includes dynamics of the patches, and in that local extinctions only occur as patches are destroyed. Simulations of the dynamics of N. pennata showed that its future metapopulation size will be overestimated unless the dynamics of the trees are accounted for. The simulation results further suggest that the dynamics of N. pennata can be characterised by the patch-tracking metapopulation model. The attempt to parameterize the L. pulmonaria metapopulation model showed that more information are required for rigorous parameterization, preferably of the past historic fire regime.