Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-04-05T15:49:37Z No. of bitstreams: 1 rodrigodemacedomello.pdf: 994495 bytes, checksum: 638cb806dcab268c132fe6aa808f1f81 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T03:49:41Z (GMT) No. of bitstreams: 1 rodrigodemacedomello.pdf: 994495 bytes, checksum: 638cb806dcab268c132fe6aa808f1f81 (MD5) / Made available in DSpace on 2016-04-24T03:49:41Z (GMT). No. of bitstreams: 1 rodrigodemacedomello.pdf: 994495 bytes, checksum: 638cb806dcab268c132fe6aa808f1f81 (MD5) Previous issue date: 2013-02-26 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / A ordem Chiroptera encontra sua maior diversidade nos trópicos, e no Brasil o número de espécies chega a 174, sendo que 60% do território permanece sem o registro de nenhuma espécie de morcego. Na Mata Atlântica, cujos remanescentes florestais ocupam somente cerca de 7% da área original, muitas áreas florestais se restringem a locais montanhosos, onde existem poucos estudos relacionados à ordem Chiroptera. O Parque Estadual do Ibitipoca (PEI) está inserido nos domínios da Serra da Mantiqueira, em área de Mata Atlântica, na Zona da Mata do estado de Minas Gerais (21º42’ S e 43º54’ W). Abrange os municípios de Lima Duarte ao sul e sudeste, Santa Rita de Ibitipoca ao norte e Bias Fortes a leste, o parque possui área de 1.488 hectares com altitudes variando entre 1.200 a 1.784 metros. Neste sentido, os objetivos deste estudo foram verificar a riqueza e diversidade de morcegos Phyllostomidae bem como estudar os hábitos alimentares dos morcegos frugívoros no PEI. O estudo foi conduzido em duas formações de Floresta Ombrófila Densa, sendo estas a Mata de Grota e a Mata Grande. Foi realizada uma comparação entre as áreas com relação à riqueza, diversidade e consumo de frutos. Os morcegos foram capturados com 8 a 10 redes de neblina durante 14 meses (abril de 2011 a maio de 2012) e quatro noites por mês totalizando 62.171,25 m2h de esforço de captura. No campo, os morcegos foram triados e mantidos por uma hora em sacos de pano de algodão para a obtenção de sementes contidas nas fezes. Após a triagem os morcegos foram soltos no local de captura e as sementes contidas nas fezes foram levadas para o laboratório para triagem e identificação. No total, foram obtidas 400 capturas, sendo 98% (12 espécies) pertencentes à família Phyllostomidae. As espécies mais abundantes foram Sturnira lilium (59,9%), Platyrrhinus lineatus (11,3%), Artibeus lituratus (8,7%) e Carollia perspicillata (7,6%). As duas áreas amostradas apresentaram diferenças relacionadas à riqueza, diversidade e composição de espécies de morcegos, sendo esta diferença influenciada predominantemente por S. lilium. É provável que as diferenças observadas na assembléia de morcegos entre as duas áreas amostradas sejam resultado de variações na composição florística. O registro de A. lituratus e P. lineatus somente em poucos meses do ano e próximo a Ficus mexiae em frutificação, sugere que estas espécies de morcegos se desloquem para o PEI durante poucos períodos do ano em busca de recurso alimentar. Os resultados obtidos no PEI, assim como dados presentes na literatura, sugerem que locais montanhosos da Mata Atlântica na Região Sudeste abriguem uma composição de espécies de morcegos diferenciada de locais mais baixos. Com relação a dieta, foram obtidas 126 amostras fecais com sementes, distribuídas em 14 espécies de plantas. Dentre estas, as mais consumidas foram Solanum swartzianum (31,1%), Ficus mexiae (23,5%), Solanum pseudoquina (9,2%) e Dyssochroma viridiflorum (8,4%). Não houve diferença na riqueza de sementes entre a Mata de Grota e a Mata Grande, porém, houve elevada diferença entre as diversidades de sementes para essas áreas. Na Mata de Grota, o consumo de F. mexiae foi mais pronunciado, por outro lado, para a Mata Grande, S. swartzianum representou expressivo consumo em relação à outra área. Sturnira lilium apresentou 71,8% de Solanaceae em sua dieta. Esta família também predominou na dieta de C. perspicillata (53,8%). Ficus mexiae constituiu a espécie de planta consumida por mais espécies de morcegos, sendo item exclusivo na dieta de A. lituratus, A. fimbriatus e Platyrrhinus recifinus, e predominante na dieta de P. lineatus. A família Solanaceae foi a que ocorreu com maior frequência ao longo dos meses. O consumo de F. mexiae em grande quantidade durante poucos meses do ano sugere que algumas espécies se deslocam para o parque durante esses períodos. Tendo em vista o importante papel ecológico dos morcegos Phyllostomidae, a carência de estudos sobre a fauna de morcegos em áreas de altitudes elevadas dificulta o conhecimento sobre a estrutura da comunidade desse grupo nestes locais. Assim, somente o incremento de estudos sobre a fauna de morcegos em locais de maiores altitudes pode gerar informações que direcionem áreas prioritárias para a preservação da ordem Chiroptera. / The order Chiroptera has its higher diversity in tropics, with 174 species in Brazil, being 60% without any registered bat species. In Atlantic Rainforest whose remnants occupy about 7% of the original area, several Forest areas are restricted to mountainous places, were there is a lack of studies related to this order. The Parque Estadual do Ibitipoca (PEI) is located at Serra da Mantiqueira, em área de Mata Atlântica, of Zona da Mata in Minas Gerais State (21º42’ S e 43º54’ W). It comprises the municipalities of Lima Duarte in South and Southeast, Santa Rita de Ibitipoca in North and Bias Fortes in East, its area has 1488 hectares with altitude varying between 1200 to 1784 meters. This Study aimed to verify the richness and diversity of bats from the Phyllostomidae family, so as to study the feeding habits of frugivorous bats in PEI. The study was conduced in two areas of Ombrophilous Dense Forest named Mata de Grota and Mata Grande. Richness diversity and fruit consumption of both areas were compared. Bats were captured with 8 to 10 mist nets during 14 months (April 2011 to May 2012) four nights a month, totaling 62.171,25 m2h of capture effort. In field, the bats were screened and kept by one hour in cotton bags for obtaining the seeds contained in faeces. After this, bats were released in capture places and the seeds contained in faeces were screened and identified in laboratory. It was realized 400 captures, being 98% (12 species) from the Phyllostomidae family. The more abundant species were Sturnira lilium (59.9%), Platyrrhinus lineatus (11.3%), Artibeus lituratus (8.7%) and Carollia perspicillata (7.6%). Both sampled areas showed difference in richness, diversity and species composition of bats, being this difference predominantly influenced by S. lilium. The difference observed in bats assemblage between the two sampled areas is probably due to a variation in floristic composition. The presence of A. lituratus and P. lineatus only in a few months and next to fruiting Ficus mexiae, suggests that these bat species dislocate to PEI for food resource. These results suggest that the bats species composition from mountainous areas of Atlantic Rainforest in Southeast is different from that found in lower sites. With regarding to diet, it was obtained 126 fecal samples with seeds from 14 plant species. Among these, the most consumed were Solanum swartzianum (31.1%), Ficus mexiae (23.5%), Solanum pseudoquina (9.2%) and Dyssochroma viridiflorum (8.4%). There was no difference in seeds richness of both areas Mata de Grota and Mata Grande, although it was observed difference in seeds diversity in these areas. In Mata de Grota, the consumption of F. mexiae was more pronounced, on the other hand, in Mata Grande, S. swartzianum presented more expressive consumption in relation to the other area. Sturnira lilium presented 71.8% of Solanaceae in its diet. This family also predominated in the diet of C. perspicillata (53.8%). Ficus mexiae was the plant species consumed by a larger number of bat species, being an exclusive item in the diet of A. lituratus, A. fimbriatus and Platyrrhinus recifinus, and predominated in the diet of P. lineatus. The family Solanaceae was the more frequent over the months. The consumption of F. mexiae in large amounts in a few months along the year suggests that some species dislocate to the park during these periods. With a view to the ecological importance of Phyllostomidae bats, the lack of studies about bat fauna in high altitude areas makes difficult the knowledge of community structure in these areas. Thus, additional studies on bat fauna from high altitude areas can provide information in order to prioritize areas for the conservation of individuals from Chiroptera order.

Coral mortality caused by El Niño–Southern Oscillation (ENSO) activity and its related disturbances has been researched throughout the Eastern Pacific. In the past three decades, disturbances related to the El Niño–Southern Oscillation (ENSO) have been shown to influence coral growth in the Eastern Pacific. In the Galápagos Islands, Ecuador, more than 97% of corals experienced mortality after the severe 1982-1983 ENSO episode. However, two of the most dominant coral species found in a coral community adjacent to Devil’s Crown; Psammocora stellata and Diaseris distorta survived this severe ENSO event. By reconstructing sediment cores of the coral community, this study assessed how the coral assemblage has changed over the past 7,700 years of the Holocene epoch. The historical reconstructions were then related to existing records of Holocene ENSO variability in order to determine if changes in the relative abundance of coral species were related to ENSO activity and disturbances. We observed high variability in the relative abundances of P. stellata and D. distorta in the cores, including an increase in the abundance of D. distorta at approximately 2,200 yBP. Between the two species, opposite abundance trends were observed and supported by Detrended Correspondence Analysis (DCA) and Non-metric Multidimensional Scaling (NMDS) ordination analysis. Overall, the high variance in coral composition at the site throughout the Holocene documents repeated disturbance events in this region.

The reported requirement for a higher weeding effort due to increased weed infestations under conservation agriculture (CA) relative to conventional mouldboard plough tillage is perceived by both smallholder farmers and extension workers as the main limiting factor to the widespread adoption of CA by smallholder farmers in southern Africa. However, proponents of CA argue that weeds are only a problem under CA in the initial two years and decline afterwards resulting in reduced labour requirements for weeding under CA. They further posit that weeds are only major problem where minimum tillage (MT) is adopted without crop residue mulching and diverse crop rotations. This thesis explores the effect of time under CA on weed population dynamics and crop growth under the recommended CA practices and actual smallholder farmer practice in semi-arid Zimbabwe. Assessment of weed and crop growth on a long-term CA experiment at Matopos Research Station revealed that the MT systems of planting basins and ripper tine were associated with higher early season weed density and biomass than conventional early summer mouldboard tillage (CONV) in both the fifth (cowpea phase) and sixth (sorghum phase) years of CA. This increased weed infestation within the first four weeks after planting in CA necessitated early weeding to provide a clean seedbed and avert significant crop yield loss. Maize mulching only suppressed early season weed growth in sorghum mostly at a mulch rate of 8 t ha-1 which is not a mulching rate that is attainable on most smallholder farms. However, the lower maize residue mulch rate of 4 t ha-1 was consistently associated with increased weed emergence and growth as from the middle of the cropping season in both crop species. The increased weed infestations under the mulch were probably due to the creation of ‘safe sites’ with moist conditions and moderate temperatures. The high weed growth under the mulch contributed to the low sorghum grain yield obtained under mulched plots. In addition, maize mulching was also associated with a less diverse weed community that was dominated by the competitive Setaria spp. and difficult to hoe weed Eleusine indica (L.) Gaertn. However, the weed community under CA was similar to that under CONV tillage with no evidence of a shift to the more difficult to control weed species. The increased early season weed growth and high weed pressure under CA meant that it was still necessary to hoe weed four times within the cropping season to reduce weed infestations and improve crop growth even after four years of recommended CA practices. Early and frequent weeding was effective in reducing weed growth of most species including Setaria spp. and E. indica demonstrating that on smallholder farms where labour is available hoe weeding can provide adequate weed control. The wider spacing recommended for use in CA contributed to the low cowpea and sorghum grain yields obtained under CA compared to CONV tillage. On smallholder farms in Masvingo District, the MT system of planting basin (PB) was the only conservation farming (CF) component adopted by farmers. There was no difference in the total seedling density of the soil weed seed bank and density of emerged weeds in the field in PB and conventional mouldboard ploughing done at first effective rains (CONV tillage). However, the first weeding in PB was done at least 15 days earlier (P < 0.05) than in CONV tillage suggesting high early season weed growth in PB relative to CONV tillage. As weed density did not decline with time in PB, weed management did not differ with increase in years under PB. Shortage of inputs such as seed and fertiliser was identified by smallholder farmers as the most limiting factor in PB crop production with the area under PB was equivalent to the seed and fertiliser provided by CARE International for most farmers. On this small area, weeds could be managed by available family labour. Double the maize grain yield was obtained in PB (mean: 2856 kg ha-1) due to improved weed management and soil fertility. However, the use of poorly stored composts was found to introduce weeds into some PB fields. The findings of this study demonstrated that weed pressure was still high and weed management were still a challenge under the practice recommended to smallholder farmers in Zimbabwe even in the sixth year of practice. There is, therefore, a need for research on the economic feasibility of using herbicides, intercropping and optimal crop density to ameliorate the high weed pressure under CA. / Thesis (PhD)--University of Pretoria, 2013. / Plant Production and Soil Science / unrestricted

Afin d’appréhender l’impact des dépôts d’azote atmosphérique sur les écosystèmes,nous nous sommes intéressés à un écosystème d’intérêt patrimonial : les prairies acides duViolion caninae. Au sein de ces prairies, les objectifs étaient de (i) quantifier les variationsfloristiques temporelles et spatiales le long du domaine atlantique français et de déterminer siles variables de dépôts d’azote et du climat expliquaient ces patrons, (ii) comprendre lesprocessus mis en jeu lors de l’enrichissement en azote au niveau de la végétation et du sol, et(iii) examiner les moyens potentiels de conservation et de restauration.L’étude temporelle et spatiale des prairies acides a permis de mettre en évidence deschangements de composition à l’échelle locale du type de communautés mais également àl’échelle nationale du domaine atlantique français. A l’échelle locale et nationale, ceschangements ont pu être reliés à des changements climatiques d’augmentation de latempérature annuelle moyenne et de diminution de la disponibilité en eau du sol. Toutefois àl’échelle locale, les plus forts changements de végétation ont été perçus pour les sites soumiségalement aux plus forts dépôts chroniques d’azote depuis les 25 dernières années. Ceschangements de composition se sont produits au détriment des espèces de petites tailles, tellesque des dicotylédones, alors que les Poacées généralistes se sont maintenues en dominant lecouvert végétal. Ces changements sont visibles dès 10-15 kg N ha-1 an-1, déterminé comme lacharge critique d’azote pour les prairies acides.L’approche expérimentale a permis de souligner les processus mis en jeu dans ceshabitats acides lors d’un apport d’azote. Notamment, l’enrichissement en azote n’entraineraitpas de compétition pour la lumière au sein de la végétation. Ce type de milieu, principalementdéfini par son caractère oligotrophe et sa faible capacité à neutraliser l’acidité du sol,semblerait donc essentiellement affecté par des mécanismes de toxicité de l’ammonium voired’acidification du milieu à long terme.Enfin, les moyens de restauration étudiés ont montré la difficulté de conserver et derestaurer de tels habitats potentiellement affectés par les dépôts d’azote. En effet, l’utilisationde fauches répétées avec exportation de la biomasse a montré son inutilité dans un systèmequi n’est pas influencé par la compétition pour la lumière. De même, l’étude des banques degraines a montré que ce pool d’espèces ne pouvait pas représenter le seul moyen deconservation des espèces caractéristiques. Ces résultats révèlent l’importance de conserver lesprairies acides existantes, principalement dans des sites soumis à de faibles dépôts ambiants. / To assess the impact of atmospheric nitrogen deposition on ecosystems, we werefocused on a patrimonial interest ecosystem: acid grasslands of Violion caninae. Within thesegrasslands, we aimed to (i) characterise temporal and spatial variation in plant speciescomposition along the French Atlantic domain and determine if nitrogen deposition andclimate variables could explain these patterns, (ii) understand processes underlined bynitrogen addition on vegetation and soil, and (iii) examine the potential conservation andrestoration ways.Temporal and spatial approach of acid grasslands brought to light changes in speciescomposition at local scale of community type but also at the national French Atlantic domainscale. At both local and national scale, these changes were linked to climate change withincrease of mean annual temperature and decrease of soil water availability. However at localscale, the most changes in species composition were experienced on sites with climate changeand also the highest chronic nitrogen deposition since the last 25 years. These changes inspecies composition occurred at the expense of short stature species like forbs whereasgrasses species were persistent and dominated vegetation. These changes are visible from 10-15 kg N ha-1 an-1, determined as the critical load for nitrogen in acid grasslands.The experiment allowed to highlight processes underlined in acid grasslands afternitrogen addition. In particular, nitrogen enrichment did not lead to light competition invegetation. These grasslands, mainly defined by poor-nutrient and low capacity to bufferacidity in soil, were essentially affected by ammonium toxicity or even acidification on thelong range.Finally, the study of conservation ways showed the difficulty to conserve and restorethe grasslands affected by nitrogen deposition. Indeed, more frequent cuttings with biomassremoval were useless in a system not influenced by light competition within vegetation. Thestudy of seed banks showed also that conservation ways could not be based just on seed banksto maintain characteristic species. These results highlight the importance to conserve theexisting acid grasslands, mostly in region with low ambient nitrogen deposition.

Sammanfattning: Wood decay fungi are the main decomposer of lignocellulose material stored in wood. Thus, all factors that affect them could affect their ecological function. This in return, may affect ecosystem functioning in terms of altered carbon emissions from dead wood. Increased temperature is one of the main factors influencing fungal decay. The aim of the current study is to explore the effects of temperature and assembly history (order of species arrival), two important regulators of fungal communities, on wood decomposition. I conducted a microcosm experiment with two temperature treatments and eight assembly histories where each species was allowed to colonize the wood two weeks ahead of the rest of the species. The temperature treatments were set to mimic the effect of climate induced warming. Therefore, I had one treatment with relatively high temperature, representing the expected temperatures year 2100 given the current emission trends of the northern inland of Sweden, and another treatment representing the current normal temperature (1961-1990). The temperature treatments had an average difference of 5°C. In order to see how climate induced warming and fungal assembly history influenced decomposition, I measured and analyzed initial fungal growth, fungal respiration and wood weight loss. Both temperature and assembly history had a significant influence on fungal growth, fungal respiration and wood decomposition. There was also strong interaction between the two factors. The average increase in mass loss under elevated temperature was 19% compared to 14% under normal temperature. The highest mass loss (25%) was when Phlebia centrifuga was the initial species under elevated temperature and the lowest (12%) was when Climacocystis borealis was initial species under normal temperature. All assembly histories had higher mass loss under elevated temperature, but the magnitude varied. For example, when C. borealis was the initial species, mass loss increased by 60% compared to only 7% when Antrodia sinuosa was the initial species. Six out of eight assembly histories had higher CO2 under elevated temperature, with the highest increase (88%) in P. centrifuga histories and the lowest (7%) in C. borealis histories. Even if the results need to be confirmed by field studies, my data illustrates that climate induced warming probably results in higher fungal respiration and deadwood decomposition and that the magnitude of this effect depends on fungal assembly history.

Grazing seems to be not only means of conserving species diversity of grasslands but also - in many cases - of its increasing. This thesis tries to find out the mechanisms of grazing that result in increased or decreased species diversity. The experiment was proceeded in Slupenec, a part of Český Krumlov, where horse pastures are situated. In order to compare grazing and mowing I collected phytosociological data from plots 1 x 1 mš. I also collected data about soil moisture, composition and pH in order to find out the main gradients in vegetation. The vegetation data from plots 20 x 20 cmš were collected before and after grazing on three pasturelands. In the chosen locality, higher level of plant species diversity have been proven on pastures in comparison with meadows. There is significantly higher percentage of plots contributing to the higher level of ß diversity on pastures than on meadows. At the same time the variability of vegetation was in most cases explained by the categorial variable pasture / meadow. Concerning selectivity of grazing, it has been proven that horses prefer grazing on species with greater cover abundance. The plots with lower rate of grazed species have got higher ß diversity. In terms of functional traits of plants, it has been proven that higher percentage of no-rosette...

Работа посвящена характеристике и экологической оценке луговых сообществ зо-лоотвалов Верхнетагильской ГРЭС и Среднеуральской ГРЭС в сравнении с зональными сообществами района Верхнетагильского района. Приводится характеристика природных условий района работ, анализ флоры высших сосудистых растений, определение домина-тов в сообществах, характеристика запаса фитомассы, экологическая оценка местообита-ний по экологическим шкалам. В результате проделанной работы было определено, что на лугах золоотвалов Верхнетагильской ГРЭС встречается 67 вида травянистых растений, относящиеся к 17 семействам и 50 родам, на лугах Среднеуральской ГРЭС - 20 видов, от-носящихся к 11 семействам и 18 родам. Большинство из видов относятся к мезофитам. По ценотическому составу преобладают луговые растения. При сравнении продуктивности лугов золоотвалов и фоновой территории выявлено, что степень восстановления продук-тивности травянистых сообществ составляет около 23 %. Оценка неоэкотопов по экологи-чески шкалам показала, что луга золоотвалов относятся к сухолуговому интервалу шкалы увлажнения и довольно богатым почвам по шкале богатства почв, в то время как луга фо-новой территории относятся к влажнолуговому интервалу. / The work is devoted to the characterization and assessment of the ecological scales of meadow communities of ash dumps of the Verkhnetagilskaya SDPP, Sredneuralskaya SDPP and zonal communities of the Verkhnetagilskaya district. The characteristics of the natural conditions of the work area, the analysis of the flora of higher vascular plants, the determination of domi-nants in the communities, the characteristics of the phytomass reserve, the ecological assessment of habitats according to ecological scales are given. As a result of the work done, it was deter-mined that in the meadows of the ash dumps of the Verkhnetagilskaya SDPP there are 67 species of herbaceous plants belonging to 17 families and 50 genera, in the meadows of the Sredneu-ralskaya SDPP - 20 species belonging to 11 families and 18 genera. Most of the species are mes-ophytes. In terms of coenotic composition, meadow plants prevail. When comparing the produc-tivity of meadows of ash dumps and the background area, it was revealed that the degree of re-covery of productivity of herbaceous communities is about 23%. Evaluation of neo-ecotopes ac-cording to ecological scales showed that ash dump meadows belong to the dry meadow interval of the moistening scale and are rather rich in soils of the wealth of soils nitrogen, while the meadows of the background territory belong to the wet meadow interval.

Management of rare and threatened species requires an understanding of processes limiting population establishment and growth. The Large blue butterfly Phengaris arion needs two other organisms, the Thyme plant Thymus serpyllum and the ant genus Myrmica, for the completion of its life cycle. The large blue butterfly is very rare in Sweden and also declining in Europe, and both the large blue and Myrmica are red-listed and in need of protection. Studies conducted in Great Britain have suggested that a lack of suitable habitat with the presence of the host plant thyme and Myrmica limits the distribution of the large blue. A good environment for the butterfly is thus a habitat where all three organisms can exist. To examine whether vegetation structure and abundance of Thymus serpyllum and Myrmica ants are good predictors of the presence of the large blue in Sweden, I investigated sites where the butterfly has been observed or reportedly gone extinct in the last five years. I studied one site in the region of Stockholm, five sites in the Uppsala region, and 10 sites on the island of Gotland. At each site, I recorded an abundance of thyme and its flowering status, the presence of shrubs, trees, and open vegetation, and any observations of the large blue.  Areas with the large blue tended to have a higher abundance of thyme plants and a higher percentage of thyme flowers in bloom during my visit than areas without the large blue. The difference in abundance of shrubs and trees between sites with and without the butterfly was small. Areas with the large blue also tended to have shrubs and trees compared to areas without the large blue. Because the study species are rare and endangered, the number of sites with current and past occurrence is limited, which complicates the statistical analysis of factors influencing its distribution. However, the results indicate the importance of a high abundance of the host plant for the occurrence of the large blue, but also that the host plant is much more common than the butterfly. Ants of the genus Myrmica were observed at only two of eight sites with observations of the large blue.  This suggests that the method used to detect Myrmica ants was not efficient, or that the large blue is not critically dependent on Myrmica ants in Sweden. To conclude, the remaining populations of the large blue should be monitored and measures to improve habitat quality should be considered at sites where it has gone extinct. We can try to reintroduce species in areas where the species has previously existed with strong populations of the thyme and the ant. Create a similar reintroduction as the success story of the large blue butterfly in Great Britain.

As abundâncias e identidades das espécies de qualquer comunidade biológica mudam tanto ao longo do espaço quanto do tempo. Não obstante, aspectos espaciais da biodiversidade têm sido muito mais explorados do que os temporais. Um dos motivos pelos quais padrões temporais têm recebido menos atenção é a escassez de estudos de longo prazo, especialmente na região neotropical, uma das mais biodiversas e ameaçadas do planeta. Estudar a dinâmica de populações e comunidades ao longo do tempo pode revelar processos ecológicos fundamentais, bem como descrever como pressões naturais e humanas afetam a biodiversidade. Entender a dinâmica das populações e comunidades envolve entender as histórias de vida dos organismos, como eles interagem com o ambiente, o papel de interações entre espécies, o papel de processos demográficos estocásticos, dentre outros fatores. Nesta tese investigamos a dinâmica temporal de populações e comunidades de borboletas e aves, e ao longo dos capítulos avaliamos o papel de diferentes processos na regulação dessas dinâmicas. No Capítulo 1 investigamos se um comportamento sazonal observado em borboletas Ithomiini (Nymphalidae, Danainae), supostamente adaptativo à seca - os \"bolsões de Ithomiini\"- seria uma simples resposta reativa à falta de chuvas ou se mecanismos endógenos (\"relógios biológicos\") estariam envolvidos. No Capítulo 2 realizamos um estudo de dinâmica populacional comparada de borboletas miméticas da tribo Ithomiini. Algumas evidências têm sugerido que além de convergir na morfologia, espécies co-miméticas tenderiam a convergir também no comportamento, no uso de microhabitats e possivelmente em suas dinâmicas populacionais. Testamos as hipóteses de que 1) pares de espécies co-miméticas (i.e., com a morfologia convergente) ou 2) pares de espécies mais próximas filogeneticamente teriam suas dinâmicas populacionais mais correlacionadas do que pares de espécies agrupados ao acaso. No Capítulo 3 descrevemos como a composição de espécies de assembleias de aves e borboletas de nove localidades tropicais e subtropicais na América do Sul e do Norte variou ao longo do tempo (anos a décadas), e se diferenças demográficas entre espécies (nicho) seriam importantes para explicar os padrões observados. No Capítulo 1 encontramos evidências de que a agregações seriam um comportamento endógeno sincronizado com o fotoperíodo, com plasticidade limitada para lidar com as alterações no regime de chuvas previstas para a região e para o continente. No Capítulo 2 encontramos que as dinâmicas populacionais de pares de espécies de Ithomiini de um mesmo anel mimético ou mais próximas filogeneticamente não tenderam a ser mais correlacionadas do que pares reunidos ao acaso, e que as espécies, anéis miméticos e subtribos estudadas tiveram suas dinâmicas temporais mais correlacionados do que seria esperado por acaso. Estes resultados e os do Capítulo 1 sugerem que na dinâmica desse sistema as pressões seletivas exercidas por fatores ambientais seriam mais importantes do que interações entre espécies. No Capítulo 3 mostramos que a composição de espécies de assembleias de aves na Amazônia, Cerrado, Mata Atlântica e Flórida se alterou ao longo dos anos, mesmo em assembleias de áreas bem preservadas. Sobreposta a essa rotatividade (turnover) interanual também encontramos rotatividade sazonal, previsível, na composição de espécies de assembleias de aves da Amazônia e da Mata Atlântica e na assembleia de borboletas Ithomiini. Padrões de rotatividade sazonal na composição de espécies podem ser mais comuns em comunidades neotropicais do que se imagina. As estratégias temporais dos organismos neotropicais, as quais parecem ser a base dos padrões sazonais observados nas comunidades, podem ser largamente determinadas por ritmos (\"relógios\") endógenos. Estudos sobre a regulação dos ritmos e estratégias temporais dos organismos, e dos efeitos das mudanças climáticas e do uso do solo sobre eles, são essenciais. Um importante passo nesse sentido é a disseminação de estudos de longo-prazo de populações e comunidades, contínuos, sistemáticos e com resolução para detectar padrões sazonais. Além disso, a interação das perspectivas, bases teóricas e abordagens da biologia molecular, fisiologia, cronobiologia e ecologia pode avançar nosso entendimento sobre os processos que moldam a dinâmica da biodiversidade e sobre as consequências das perturbações humanas sobre os ecossistemas / The species abundances and identities of any biological community change both over space and time. Nevertheless, Spatial biodiversity dimensions have been much more exploited than temporal ones. One of the reasons for which temporal patterns have received less attention is a scarcity of long-term studies, especially in the neotropical region, one of the most biodiverse and endangered on the planet. Studying the dynamics of populations and communities over time can reveal key ecological processes as well as describe how natural and human pressures affect biodiversity. Understanding the dynamics of populations and communities involves understanding organisms life histories, how they interact with the environment, the role of interactions among species, the role of stochastic demographic processes, and other factors. In this dissertation we investigated the temporal dynamics of butterflies and birds populations and assemblages, and throughout its chapters we evaluate the role of different processes in the regulation of dynamics. In Chapter 1 we investigated whether a seasonal behavior observed in butterflies Ithomiini (Nymphalidae, Danainae), supposedly adaptive to dissecation - the \"Ithomiini pockets \" - is a simple reactive response to drought or there is internal time-keeping mechanisms involved. In Chapter 2, we performed a comparative population dynamics study of mimetic butterflies of the Ithomiini tribe. Some evidence has suggested that besides the convergence in morphology, co-mimetic species would tend to converge also in behavior, in the use of microhabitats and possibly in their population dynamics. We hypothesized that (1) pairs of co-mimetic species or (2) pairs of species more phylogenetically related would have their population dynamics more correlated than pairs of species grouped at random. In Chapter 3 we described how species composition of bird and butterfly assemblages from nine tropical and subtropical locations in South and North America varied over time (years and decades), and if demographic differences between species (niche) are needed to explain observed patterns. In Chapter 1 we found evidence that Ithomiini pockets are regulated by internal time-keeping mechanisms synchronized to photoperiod, and that mechanism has limited plasticity to cope with rainfall regime changes predicted for the study region and for the continent as a whole. In Chapter 2 we found that the population dynamics of Ithomiini species pairs more phylogenetically related or belonging to the same mimetic ring did not tend to be more correlated than pairs assembled at random, and that the species, mimetic rings and subtribes had their temporal dynamics more correlated than would be expected By chance These results and those of Chapter 1 suggest that this system dynamics is more influenced by selective pressures exerted by environmental factors than by species interactions. In Chapter 3 we show that the composition of bird assemblages in the Amazon, Cerrado, Atlantic Rainforest, and Florida has changed over the years, even in assemblies of well-preserved areas. Superimposed to this interannual turnover we also found seasonal, predictable turnover in species composition of bird assemblages of the Amazon and Atlantic Forest and in the Ithomiini butterflies assembly. Patterns of seasonal turnover in species composition may be more common in neotropical communities than is imagined. The temporal strategies of neotropical organisms, which appear to be the basis of the seasonal patterns observed in communities, can be largely determined by endogenous rhythms (\"biological clocks\"). Studies on the regulation of organisms\' temporal rhythms and strategies, and the effects of climate change and land use on them, are essential. An important step in this direction is the dissemination of continuous, systematic, population and community long-term studies, with sampling resolution to detect seasonal patterns. In addition, the interaction of perspectives, theoretical basis, and approaches of molecular biology, physiology, chronobiology, and ecology can advance our understanding of the processes that shape biodiversity dynamics and the consequences of human disturbances on ecosystems

Many regional and local factors can influence the distribution of native and exotic species in ecological communities. I examined the regional- and local-scale determinants of native and exotic vascular plant species richness and composition in a highly fragmented oak savanna ecosystem on southeastern Vancouver Island. In sharp contrast to most reported results, I found a negative relationship between native and exotic richness at the regional scale, and no relationship at the local scale. Two extrinsic factors, surrounding road density and climate, best explained the regional-scale relationship by each affecting natives and exotics in opposite ways. Road density and climate were also the dominant predictors of native and exotic composition at the regional scale. Patterns in the patch occupancy of individual species confirmed the importance of these factors but I found that low surrounding road densities and cool, wet conditions predicted the presence of many natives and the absence of many exotics. Environmental factors explained variation in richness and composition at the local scale, but these factors were different for natives and exotics. My results suggest that natives and exotics respond to roads and climate in fundamentally different ways. Roads increase both exotic propagule pressure and disturbance, which may facilitate exotic invasion. In contrast, disturbance from roads may increase the likelihood of local extinction for particular natives. Differing climatic preferences within the native and exotic species pools may also partially explain the observed patterns. There was no evidence that native diversity directly affects exotic diversity (or vice versa). Surprisingly, I found that connectivity was not an important predictor of richness or composition despite the high degree of habitat fragmentation in this ecosystem.