The majority of vertebrates are tropical, existing in an environment with low temperature seasonality. However, there is a strong research bias towards temperate-zone studies of seasonality. I investigated the timing of life history stages and trade-offs in tropical rufous-collared sparrows (Zonotrichia capensis) in the humid Andes of Ecuador, then compared my data to temperate-zone Zonotrichia. In Chapter II, I investigated the function of male territorial aggression. Males had peak territorial aggression scores during pre-breeding and nesting, suggesting that paternity protection and food resource defense are the primary selective forces shaping male territorial behavior. Territorial aggression responses depended on the life history stage of males, which were not synchronized within the general population. In Chapter III, I tested for a trade-off between male territorial aggression scores and paternal provisioning rate. Males with higher provisioning rates had nestlings with larger body size, but contrary to the findings of previous studies, there was no direct relationship between aggression and paternal provisioning. In Chapter IV, I investigated how Z. capensis allocated supplemental food. Previous studies (mainly in temperate-zone breeding birds) found food supplements were allocated to reproduction. We supplemented fed birds in both non-breeding and feeding fledglings life history stages; both groups molted (replaced feathers) in response to supplementation, thus invested in their own maintenance over immediate reproduction. In Chapter V, I tested whether latitude and/or altitude are good predictors of reproductive synchrony in Zonotrichia. Reproductive synchrony indices overlapped among tropical and temperate populations. The high altitude, temperate-zone Zonotrichia population had the highest synchrony index, but there was only a weak relationship of altitude in a comparison of tropical populations. Cumulatively I found that tropical humid-forest resident Z. capensis time life history stages according to individual condition and history and not by overarching climatic cues. / Ph. D.

Hurricane Florence (2018) was unique due to its slow storm motion during landfall, causing convective rainbands to produce high amounts of precipitation along the coast of North Carolina. This study focuses on the relationship between precipitation asymmetries and atmospheric stability surrounding the tropical cyclone (TC) during the landfall period of a nearly-stationary TC. Previous research with idealized hurricane simulations suggests that atmospheric stability may vary surrounding a TC during landfall, with the atmosphere destabilizing offshore and stabilizing onshore. However, this finding has not been studied using a realistic approach. Due to Hurricane Florence's slow motion, the storm was situated at the land-ocean boundary for multiple days, providing an ideal opportunity to examine the role of atmospheric stability in modifying hurricane precipitation during landfall. This study uses the Advanced Research Weather Research and Forecasting (WRF-ARW) version 3.6.1 to produce high-resolution simulations to examine the variations in precipitation and atmospheric stability surrounding Hurricane Florence. Precipitation accumulation at different temporal scales was used to determine that asymmetries existed during the landfall period. Observed and model-simulated Convective Available Potential Energy (CAPE) were used to measure stability surrounding the TC. Simulated CAPE indicates that there was a significant difference between stability right- and left-of-track. In addition to a control simulation, two experimental simulations were conducted by modifying the land surface to vary the heat and moisture exchange coefficient (HS) and hold the surface roughness (Z0) constant. By isolating the HS to be more moist or dry, the altered low-level moisture was hypothesized to cause the precipitation and convection distributions to become more symmetrical or asymmetrical, respectively. The results from the experimental simulations showed that the altered land surface affects the relative humidity from the surface to 950 mb, which has an immediate impact on stability off-shore left-of-track. Overall, the precipitation and stability asymmetries were not significantly impacted by the altered near-surface moisture, indicating other physical factors contribute to the asymmetries. The results of this study provide insight into the role of atmospheric instability in generating asymmetrical precipitation distributions in landfalling TCs, which may be particularly important in slow-moving TCs like Hurricane Florence. / Master of Science / Landfalling tropical weather systems such as hurricanes can significantly impact coastal communities due to severe flooding and damaging winds. Hurricane Florence (2018) affected coastal and inland communities in North Carolina and South Carolina when the storm produced a significant amount of precipitation over the coastal region. During landfall, the center of Hurricane Florence moved slowly parallel to the coastline, which creates a suitable time frame to isolate and study the influence of landfall on precipitation asymmetries. Precipitation asymmetry occurs when more rainfall falls on one side of the hurricane; for example, heavier precipitation tends to occur on the right side of a hurricane during the landfall period. Hurricane rainbands that are responsible for producing heavy precipitation form in areas where there is higher moisture near the surface while lighter precipitation forms in areas where there is drier air near the surface. This study focuses on the relationship between land surface moisture and spatial variations of precipitation during the hurricane landfall period by studying observations and model simulations of Hurricane Florence. The model simulation of Hurricane Florence found that more precipitation fell on the right side of the storm, indicating that there was precipitation asymmetry. In order to understand how the precipitation asymmetries form, the model simulation of Hurricane Florence was modified to create two experiments. In the first experiment, the land surface was altered to have a moister land surface, which should cause the hurricane precipitation to be more symmetrical. In the second experiment, the land surface was altered to have a drier land surface, which should cause stronger precipitation asymmetry. However, the results did not match this expectation. Instead, both experiments simulated asymmetrical precipitation with more precipitation falling on the right side of each storm during the landfall period. These results suggest that the modified land surface moisture did not have a significant impact on the formation of precipitation asymmetries. Other factors are therefore suggested to have a more dominant influence on the development of precipitation. Overall, this work can support future studies by ruling out the impact of land surface moisture on a hurricane's precipitation formation during the landfall period.

This thesis explores the effect of climate on the development of high density housing. With the situation in Lagos there is a tendency to neglect the effect of climate. The low income housing project proposed under the Ijaiye housing scheme is used as a vehicle to investigate this climatic concerns. The conditions that generated the design included site conditions, climate, human comfort criteria, building materials, and construction. The issues that were dealt with include ventilation, protection from direct solar radiation, treatment of common spaces, orientation, drainage, and the choice of building materials. The design solution submitted in this thesis is influenced by various sources from the field of tropical architecture with the understanding that these studies are not definitive and that further investigation still needs to be made. / Master of Architecture

While conventional drought has been studied for many years, new research focuses on different aspects and types of drought. Flash Drought is a relatively new area of research in drought literature, dating back to the last ten to twenty years in the United States. Flash drought in the Caribbean has received minimal attention from researchers, but it has been studied in the United States primarily because of the 2012 flash drought event over the Great Plains. This study focuses on flash drought events in Puerto Rico and the Caribbean. Because the rapid onset and intensity of flash drought can potentially cause more devastation without established prediction methods, this research seeks to understand the synoptic scale atmospheric drivers of flash drought events. Recent occurrences of a flash drought event in this region include the 2015 event in Puerto Rico, which resulted in water rationing and shortages for residents of the island (Mote et al., 2017). The primary goal of this study is to understand how flash drought initiates and propagates for Puerto Rico and the Caribbean using two definitions of flash drought. One definition is based on soil moisture deficit, and the second definition is based on the Evaporative Demand Drought Index (EDDI), an experimental drought monitoring tool. Results suggest that an anomalous convection and positive moisture event followed by negative moisture anomalies and persistent subsidence contribute to flash drought event initiation and propagation. Additionally, large scale flash drought events seem to be initiating more frequently, suggesting that the island is becoming more susceptible to the devastations of flash drought. / Master of Science / Drought in the United States is a well-known occurrence typically caused by high temperatures and low precipitation rates. States in the Western US like California, Arizona, Nevada, and more have been negatively impacted by persistent drought. These negative impacts include water rationing laws, struggling agricultural yield, and many days without precipitation. In recent years, it has been discovered that drought has a counterpart known as flash drought. Flash drought is to flash flooding as drought is to a floodplain. Floodplains are areas prone to persistent flooding, but flash flooding occurs in a matter of minutes or hours due to extremely intense precipitation and a lack of drainage for the water to leave. Flash drought is very similar to flash flooding due to the rapid onset and intensification. Flash drought has been studied for the United States in some cases, but there is very little known about flash drought in Puerto Rico and the Caribbean. This study seeks to understand how flash drought initiates and intensifies in Puerto Rico. Results of this study suggest that flash drought can initiate immediately after a large precipitation event that is followed by days without precipitation. Because of the amount of moisture after the precipitation, the atmosphere wants to evaporate that moisture back out. As more moisture is evaporated, the land becomes drier and drier, especially when there is no follow up precipitation. The lack of follow up precipitation is also explained in this study. It was found that following the big precipitation event, the atmosphere does not create more precipitation because of a persistent state of downward vertical motion. Upward vertical motion is needed for precipitation to occur, so the combination of downward vertical motion and dry air results in a flash drought event in Puerto Rico.

Approved for public release, distribution is unlimited / This thesis investigated the hypothesis that variations in tropical cyclone (TC) activity in the western North Pacific (WNP) may affect the teleconnection between the tropical WNP and North America. The teleconnection patterns of the 500 hPa geopotential height between a base point in the WNP (20 N 115 E) and a domain over North America (30 - 45 N, 70 -90 W) from 1951-2001 were examined. The 25 most active and the 25 least active TC years for two regions with the highest climatological average of TC activity, near the Philippines and Taiwan, respectively, were compared to determine if stronger teleconnection patterns occur during the more active years. For both regions, the correlation pattern is significant during active years and insignificant during inactive years, with the results based on TC activity in the Philippines region showing a larger difference. An analysis of 500 hPa mean winds showed weaker winds in the midlatitudes during active TC years when the teleconnection is stronger, which suggests that the teleconnection may consist mainly of Lau and Weng's (2000) zonally-elongated mode (Mode 1). Further cross correlations of the geopotential height and TC frequency parameters with the tropical eastern and western Pacific sea-surface temperatures (SST's) showed a significant correlation between TC activity and tropical eastern Pacific SST's, but the North America-WNP correlation is unlikely to be a result of a direct influence of SST's on the two regions. / Captain, United States Air Force

Le mercure suscite beaucoup d'attention de par les conséquences sanitaires et environnementales qu'il engendre. Son impact est particulièrement important dans la région amazonienne et en particulier en Guyane française où les teneurs en mercure sont naturellement élevées dans les sols, et s'ajoutent celles liées aux activités d'orpaillage. Si l'impact du mercure dans les milieux aquatiques a été largement étudié, peu d'études ont évalué son impact dans les milieux terrestres, où il est préférentiellement stocké. Dans ce contexte, les interactions entre les vers de terre, organismes ingénieurs des sols, et le mercure ont été étudiées dans des sols tropicaux, avec comme objectifs : i) d'évaluer l'abondance et la diversité des vers de terre in situ en lien avec le mercure, ii) d'évaluer expérimentalement la résistance au mercure d'une espèce de ver tropical présente sur le site d'étude et iii) d'évaluer l'impact en microcosmes de l'activité des vers de terre sur la mobilité et la répartition du mercure dans les sols. Ces objectifs ont été appréhendés au travers de trois volets, avec comme matériel d'étude des sols naturels (oxisols et sols hydromorphes) et des vers de terre tropicaux provenant d'un site orpaillé, situé dans les environs de Cacao, en Guyane française. Dans le premier volet, un échantillonnage standardisé des vers de terre (TSBF), a permis de proposer des espèces putatives (ou MOTUs) à partir de méthodologies de délimitation basées sur le barcode ADN. Ces MOTUs ont ensuite été identifiés morphologiquement, parmi lesquels Pontoscolex corethrurus, une espèce pantropicale considérée comme pérégrine. De plus, les caractéristiques des sols et les teneurs en mercure ont été déterminés afin de tenter d'expliquer la distribution des vers sur le site étudié. P. corethrurus se retrouve exclusivement dans l'oxisol, qui contient les concentrations les plus élevées de mercure total. Le second volet de ce travail a été consacré à l'étude de l'impact du mercure sur l'espèce tropicale P. corethrurus, à travers une approche écotoxicologique où le vers de terre a été exposé à différentes concentrations de mercure dans un oxisol dopé au laboratoire (HgCl2). Les résultats obtenus ont confirmé la résistance de cette espèce à des concentrations de mercure allant jusqu'à 20 µg g-1 de sol et ont révélé sa forte capacité bioaccumulatrice. Les résultats précédemment décrits ont ouvert la voie à un troisième volet où deux études en microcosmes se sont attachées à étudier l'impact des vers de terre sur la mobilité et la disponibilité du mercure (a) dans des conditions proches de celles rencontrées en conditions naturelles (fond géochimique), et (b) en présence d'une forte concentration pouvant être rencontrée sur les sites orpaillés (20 μg Hg g-1 de sol). Les résultats obtenus ont montré que les vers de terre agissent sur la mobilité du mercure directement par modifications physico-chimiques des sols (augmentation du pH et COD) et indirectement par stimulation des communautés bactériennes totales du sol. En conclusion, notre étude a montré que (1) P. corethrurus est une espèce résistante au mercure de par sa présence sur notre site d'étude et les résultats du test écotoxicologique mené au laboratoire, ce qui confirme l'idée d'un modèle tropical pour ce type d'étude ; (2) la bioaccumulation du mercure mesurée chez les vers de terre est importante et pourrait ainsi être responsable de l'entrée du mercure dans la chaîne terrestre trophique ; et (3) les vers de terre jouent un rôle dans la mobilité du mercure, modifiant sa partition dans les sols et diminuant les conséquences environnementales liées à sa biodisponibilité / Mercury is of major concern because of health and environmental problems that they cause. This toxic pollutant is particularly prevalent in tropical Amazonian regions and in French Guiana where soils are naturally rich in mercury and past and present gold mining activities occurred. While many studies have shown the impact of mercury in aquatic environments, to our knowledge only a few have focused on terrestrial ecosystems, where mercury is predominantly found. This doctoral research examined the interactions between earthworms, which are soil engineers, and mercury in a tropical soil from French Guiana. The objectives of the research were to: i) evaluate in situ earthworm diversity and distribution in soils related to mercury concentrations, ii) evaluate experimentally the impact of mercury on a tropical earthworm species present in our study site, and iii) evaluate the impact of earthworms on mercury mobility and availability in different soils. In order to achieve these objectives, three studies were conducted using natural tropical soils (oxisols and hydromorphic soils) and tropical earthworms sampled in a small catchment basin located near Cacao, in French Guiana. In the first part, earthworms were collected in the field using the standard TSBF method, and species delimitation was done based on DNA barcoding. Putative species were then morphologically identified, among them Pontoscolex corethrurus, a pantropical and peregrine species. Furthermore, soil characteristics and mercury concentrations were determined, and a first attempt was made to explain earthworm distribution in the field. P. corethrurus was found only in the oxisol, which contained highest mercury concentrations in the field. In the second part, an ecotoxicological study was done using a natural tropical soil in order to assess the impact of mercury on the identified tropical species: P. corethrurus. The results showed that P. corethrurus can resist up to high mercury concentrations ; it was not affected until 20 µg Hg g-1 soil and showed high capacity of Hg bioaccumulation. These results were used for the third part of the thesis. In the last part, two studies were conducted in controlled conditions in order to assess the impact of earthworms on mercury mobility and availability in soils. For these studies, conditions near natural conditions and also a high mercury concentration were applied to the soil (20 μg Hg g-1 soil). Results showed the impact of earthworm on mercury mobility and availability through different mechanisms: directly, through soil modifications (increase of soil pH and DOC), and indirectly, through stimulation of the soil microbial population. Furthermore, results confirmed the high capacity of earthworms for mercury bioaccumulation. In conclusion, we showed that (1) P. corethrurus is resistant to mercury, due to its presence in our field contaminated site and the results of the toxicity test done in the laboratory, thus confirming the use of a tropical species for these studies ; (2) mercury bioaccumulation measured in earthworms is important and thus could be responsible for its entry and biomagnification in the terrestrial food chain ; and (3) earthworms affect mercury mobility modifying its fractioning in soils and decreasing its availability

A inclusão de óleos essenciais em suplementos concentrados de bovinos de corte recriados e terminados em pastejo pode melhorar a eficiência da fermentação ruminal, devido às suas propriedades antimicrobianas e terapêuticas. Dois experimentos foram conduzidos para investigar a inclusão de uma mistura de óleos essenciais (MOE; Crina ®) composta por Timol, Eugenol, Vanilina e Limoneno sobre o consumo de forragem e total, digestibilidade aparente dos nutrientes, parâmetros ruminais e o crescimento microbiano. Para a realização do do Experimento 1, 12 bovinos machos não castrados, da raça Nelore com 436 ± 34,14 kg de peso corporal inicial médio (PCI) foram distribuídos em três Quadrados Latinos 4 X 4. Foram avaliadas doses da MOE e os tratamentos consistuídos por: Controle (0 mg), 100 mg, 200 mg e 400 mg de MOE para cada 100 kg peso corporal (PC). Todos os animais receberam suplemento proteico-energético na dose de 0,3% do PC (matéria natural) com os respectivos tratamentos. Os animais foram alocados em um piquete de 2,2 ha de Brachiaria brizantha cv. Xaraés, sob lotação contínua. No Experimento 2, foram utilizados oito bovinos, machos não castrados da raça Nelore com 481,8 ± 28,2 kg de PCI, dispostos em 2 Quadrados Latinos 4 X 4. Foram avaliados 2 aditivos, monensina sódica (Rumensin ®) e MOE+AM (Crina ® combinado com &#945- amilase) para bovinos na fase de terminação em pasto com dois níveis de suplementação (1% x 1,5% do PC). Os tratamentos testados foram: T1) monensina + 1% do PC; T2) monensina + 1,5% do PC; T3) MOE+AM + 1,0% do PC; T4) MOE+AM + 1,5% do PC de suplemento proteico-energético. Os animais foram alocados em um piquete de 2.2 ha de Brachiaria brizantha cv. Xaraés, sob lotação contínua. As análises estatísticas foram conduzidas com a utilização do programa estatístico SAS. No Experimento 1 a inclusão de doses da MOE na dieta não afetou (P>0,10) o consumo e a digestibilidade aparente dos nutrientes, a concentração de AGCC totais, as proporções molares de acetato, propionato, butirato, isobutirato, isovalerato, a relação acetato:propionato e a concentração de N-NH3 no fluido ruminal. Houve efeito linear positivo de doses crescentes da MOE na dieta sobre o pH ruminal e efeito quadrático na proporção molar de valerato. A inclusão de doses de MOE na dieta também não afetou (P>0,10) o N ingerido, N excretado (fezes), N absorvido e a síntese microbiana em bovinos mantidos em pastagens tropicais suplementados com suplemento proteico-energético na dose de 0,3% do PC. No Experimento 2, houve interação entre aditivo e nível de suplemento para todas as variaveis de consumo (kg e %PC) avaliadas (P<0,10). A suplementação com 1,5% do PC aumentou o CMSt, o CMO, CMSD e o CMOD dos animais suplementados com monensina, mas não nos animais suplementados com MOE+AM. Na presença de MOE+AM o nível alto de suplementação (1,5% do PC) causou redução no CMS de forragem e consequentemente no consumo de FDN. As digestibilidades da MS e da PB foram maiores nas dietas com nível de suplementação de 1,5% do PC que nas de 1% do PC (P<0,10) independente do aditivo fornecido. As digestibilidades da MS, MO, FDN e PB foram maiores nas dietas contendo monensina em comparação com MOE+AM, independentemente do nível de suplemento fornecido. A suplementação com MOE+AM resultou em menor pH ruminal, maior concentração 7 molar de AGCC e maior proporção molar de C2 que a monensina (P<0,10). A suplementação com 1,5% do PC reduziu o pH ruminal, a proporção molar de C2, e aumentou a concentração ruminal de N-NH3, a concentração molar de AGCC e a proporção molar de valerato (P<0,10). Houve interação (P<0,10) entre nível de suplemento e aditivo para a proporção molar de C3, de isobutírico, de isovalérico e para a relação C2:C3. Tanto a monensina quanto o nível alto (1,5% PC) de suplementação aumentaram a proporção molar de C3, entretanto, não houve diferença entre os tratamentos monensina + 1,0% PC e MOE+AM + 1,5% PC. A relação C2:C3 foi reduzida tanto pela monensina quanto pelo nível de suplementação de 1,5% PC, entretanto, o efeito da monensina só ocorreu em combinação com suplementação a 1,0% PC. A suplementação com MOE+AM aumentou (P<0,10) a eficiência e a produção de proteína microbiana em comparação com a monensina, enquanto o nível de suplementação não teve efeito (P>0,10) sobre esses parâmetros. / The inclusion of essential oils in supplements for growing and finishing grazing cattle can improve the efficiency of ruminal fermentation due to its antimicrobial and therapeutic properties. Two experiments were conducted to investigate the effects of of the inclusion of a mixture of essential oils (EOM; Crina®) composed of Timol, Eugenol, Vanillin and Limonene in supplements for grazing beef cattle on forage intake, total dry matter intake, apparent digestibility of nutrients, ruminal parameters and microbial growth. In Experiment 1, twelve Nellore bulls with IBW of 436 ± 34.14 kg were alloted to three 4 X 4 Latin Squares. Four doses of EOM were evaluated: Controll (0 mg), 100 mg, 200 mg e 400 mg for every 100 kg of body weight (BW). All the animals were fed an energy-protein supplement at 0.3% BW (AF). The animals grazed a 2.2 ha paddock of Brachiaria brizantha cv. Xaraés, under continuous stocking. In Experiment 2, eight Nellore bulls with IBW of 481.8 ± 28.2 kg, were allotted to two 4 x 4 Latin Squares. Two feed additives, monensin (MON; Rumensin®) and a mixture of essential oil (EOM+AM; Crina® combined with exogenous &#945-amylase), were compared for grazing cattle fed an energy-protein supplement at 1.0 or 1.5% of BW (AF). Treatments were: MON+1%, M+1.5%, EOM+1.0% and EOM+1.5%. The animals grazed a 2.2 ha paddock of Brachiaria brizantha cv. Xaraés, under continuous stocking. Statistical analyzes were performed using the SAS statistical program. In Experiment 1, doses of EOM had no effect (P>0.10) on DMI, apparent digestiibility of nutrientes, ruminal concentration of SCFA, molar concentrations of acetate, propionate, butirate, isobutirate, isovalerate, the C2:C3 ratio and on the rumen concentration of N-NH3. There was a positive linear effect (P<0.10) of doses of EOM on rumen pH and a quadratic effect (P<0.10) on proportion of valerate. The EOM had no effect (P<0.10) on N ingested, N excreted, N absorbed and on microbial synthesis and efficiency. In Experiment 2, there was interaction between feed additive and supplement level for all consumption variables (kg and% BW) evaluated (P <0.10). Supplementation with 1.5% of BW increased DMI, OMI, DDMI and DOMI of animals supplemented with monensin, but not in animals supplemented with EOM+AM. In the presence of EOM+AM, the high level of supplementation (1.5% of CP) caused a reduction in forage DMI and consequently in the consumption of NDF. The digestibilities of DM and CP were greater for cattle supplemented at 1.5% of BW than at 1.0% of BW (P<0.10) regardless of the feed additive. The digestibilities of DM, OM, NDF and CP were greater in diets containing monensin compared to EOM+AM, regardless of the supplement level provided. The supplementation with EOM+AM resulted in lower ruminal pH, greater molar concentration of total VFA and greater molar proportion of C2 than monensin (P<0.10). Feeding supplement at 1.5% of BW decreased rumen pH, molar proportion of C2, and increased the concentration of rumen N-NH3, total VFA and the molar proportion of valerate (P<0.10). There was interaction (P<0.10) between feed additive and level of supplement for molar proportion of C3, isobutyrate, isovalerate and for the C2:C3 ratio. Both monensin and the high level of supplement (1.50% of BW) increased ruminal proportion of C3, however, there was no difference between the treatments monensin + 1.0% of BW and EOM+AM + 1.5% of BW. The ratio C2:C3 was decreased by both monensin and supplement fed at 1.50% of BW, 9 however, the monensin effect occurred only when combined with supplement fed at 1.0% of BW. The EOM+AM increased (P<0.10) the efficiency and production of microbial protein compared with monensin, while the level of supplement had no effect (P>0.10) on those parameters.

O aumento do consumo de agrotóxicos, em geral nos países em desenvolvimento cuja base econômica é a agricultura, como no Brasil (primeiro no ranking mundial), tem sido relacionado à expansão da degradação dos ecossistemas e à perda da biodiversidade, principalmente das espécies não alvo, incluindo ainda os riscos inerentes à saúde humana. Além disso, a ausência de políticas e programas mais efetivos relacionados à regulação e uso de agrotóxicos no Brasil, bem como o estabelecimento de normas restritivas baseadas em resultados gerados em países de clima temperado, tornam-se cada vez mais preocupantes, pois podem subestimar os reais riscos da contaminação ambiental por agrotóxicos em ecossistemas tropicais. Nesse contexto, o presente estudo teve como objetivo avaliar os efeitos diretos e indiretos do agrotóxico pyrimethanil, um fungicida utilizado em diversas culturas de climas temperado e tropical, sobre a comunidade aquática tropical, considerando experimentos laboratoriais e o uso de modelos ecossistêmicos para avaliação destes efeitos. Para atender aos objetivos propostos foram realizados testes de toxicidade com as espécies Pseudokirchneriella subcapitata (alga), Ceriodaphnia silvestrii e Daphnia similis (zooplâncton) e Danio rerio (peixes), além de um experimento em mesocosmos, monitorado em longo prazo (durante 15 dias antes e 366 dias após a contaminação), avaliando as variações físicas e químicas, bem como as respostas das comunidades zooplanctônicas e fitoplanctônicas frente à contaminação por pyrimethanil, em uma concentração média de 1,36 mg.L-1. Nos testes de toxicidade, as CEs obtidas foram de 0,67 mg.L-1 (crônica) e 3,26 mg.L-1 (aguda) para C. silvestrii; de 3,65 mg.L-1 (agudo) para D. similis; de 9,65 mg.L-1 para P. subcapitata e para D. rerio os valores obtidos para imobilidade foram de 10,45 mg.L-1 (96h) e 13,77 mg.L-1(48h) e para a mortalidade foram de 27,45 mg.L-1 (96h) e 32,17 mg.L-1 (48h). Pelos resultados dos experimentos em mesocosmos verificaram-se efeitos negativos diretos sobre o zooplâncton (redução da densidade e alteração na composição de espécies) e indiretos sobre o fitoplâncton, decorrentes da diminuição da pressão de pastagem, além do desaparecimento de algumas espécies mais sensíveis. Os efeitos tóxicos observados foram além do período em que foi observada a degradação completa do pyrimethanil, demonstrando o alto impacto do agrotóxico em ecossistemas aquáticos e a complexidade da dinâmica desse tipo de contaminação em ecossistemas naturais. O design experimental revelou-se adequado, gerando informações importantes sobre os impactos dos agrotóxicos nos ecossistemas aquáticos. A partir dos resultados obtidos sugere-se que a utilização de espécies nativas de regiões tropicais seja ampliada nos testes de toxicidade laboratoriais, sendo fundamental que os mesmos sejam complementados com os experimentos em modelos ecossistêmicos, o que permite uma avaliação dos efeitos diretos e indiretos dos contaminantes em nível de população e comunidade, bem como uma melhor compreensão destes efeitos nas funções e serviços ecossistêmicos. / The increase in the consumption of pesticides, mainly in developing countries whose economic base is agriculture, as Brazil (first in the world ranking), has been associated to the expansion of ecosystem degradation and biodiversity losses, especially of non-target species, also including the risks to human health. In addition, the absence of policies and effective programs related to the regulation and use of pesticides in Brazil, and the establishment of restrictive standards based on results generated in temperate countries, make it becomes increasingly worrisome because it may underestimate the real risks of environmental contamination by pesticides in tropical ecosystems. In this context, the present study aim to evaluate the direct and indirect effects of the pesticide pyrimethanil, a fungicide used in many temperate and tropical crops, upon a tropical aquatic community, considering laboratory experiments and the use of ecosystem models to evaluate these effects. To achieve the proposed objectives toxicity tests were performed with the species Pseudokirchneriella subcapitata (algae), Ceriodaphnia silvestrii and Daphnia similis (zooplankton) and Danio rerio (fish), as well as an experiment in mesocosms, monitored for a long-term (15 days before and 366 days after infection), evaluating the physical and chemical variations, and also the responses of phytoplankton and zooplankton communities across the pyrimethanil contamination in an average concentration of 1.36 mg.L-1. In toxicity tests, the ECs obtained were 0.67 mg.L-1 (chronic) and 3.26 mg L-1 (acute) for C. silvestrii; 3,65 mg.L-1 (acute) for D. similis; 9.65 mg.L-1 for P. subcapitata; and the values obtained for D. rerio immobility were 10.45 mg.L-1 (96h) and 13.77 mg.L-1 (48h) and mortality were 27.45 mg.L-1 (96h) and 32.17 mg.L-1 (48h). The results of the experiments in mesocosms showed direct negative effects on zooplankton (reduced density and change in species composition) and indirect effects on phytoplankton, resulted from the decrease in grazing pressure in addition to the exclusion of some sensitive species. Even after the complete degradation of pyrimethanil, toxic effects were observed, demonstrating the high impact of this pesticide on aquatic ecosystems and the complexity of the dynamics of this type of contamination in natural ecosystems. The design of the experiment revealed to be appropriate for the study, generating important information about the impacts of pesticides on aquatic ecosystems. From the results, it is suggested an increase in the use of native tropical species in the toxicity laboratory tests. Also, this process should be complemented with experiments in ecosystem models, allowing the evaluation of the direct and indirect effects of contaminants in the population and in community level as well as a better understanding of these effects on ecosystem functions and services.

Neste trabalho são estudadas epífitas, aqui consideradas como plantas vasculares usualmente encontradas sobre outras, sem parasitá-las, durante alguma fase do ciclo de vida. O local de estudos, a reserva da Cidade Universitária "Armando de Salles Oliveira" (aproximadamente 46o43’W, 23o33’S), em São Paulo-SP, é uma ilha de mata secundária em ambiente urbano e representa uma das poucas áreas cobertas por floresta na região. O clima em São Paulo é Cwa, com temperatura média anual de 19,2oC e precipitação de 1207 mm. As famílias de epífitas representadas são Polypodiaceae (9 espécies), Bromeliaceae (8), Orchidaceae (6), Moraceae (5), Araceae (4), Cactaceae (3), Piperaceae (1), Blechnaceae (1) e Araliaceae (1), totalizando 38 espécies, 3 delas exóticas. As epífitas representam 12% do total de espécies vasculares citadas para a reserva. Esta riqueza em espécies é maior do que seria esperada, dada a pequena pluviosidade local. Estão representadas todas as principais formas de vida epifíticas conhecidas. A estrutura do componente epifítico foi estudada em uma área contígua de 2000 m2 no interior da reserva, sobre todas as árvores de perímetro do caule a 1,30 m de altura (PAP) > 40 cm. As árvores foram mapeadas e espécie, altura, PAP e presença ou ausência de lianas foram registradas para cada uma delas. Dos 86 indivíduos arbóreos, 29 são de Alchornea sidifolia, 10 de Croton floribundus e 8 de Piptadenia gonoacantha, as espécies mais abundantes. Pterocarpus rohrii, Rollinia sylvatica e Myrcia tenuivenosa são citações novas para a reserva. Foram reconhecidas 2 subáreas na área amostrada, com base no estádio sucessional das árvores, evidenciando o caráter de mosaico da vegetação. Análises de distribuição de freqüências de DAP indicam o declínio das espécies mais abundantes e prevêem profundas alterações na estrutura da floresta. Foi feito um censo total dos indivíduos epifíticos com mais de 15 cm de comprimento presentes sobre todas as árvores amostradas. Foi considerado como indivíduo cada colônia, ou grupo compacto de plantas distintamente separado de outros da mesma espécie. Foram encontrados 380 indivíduos, sobre 58 árvores (67% do total). Para cada um deles foram registrados altura de fixação, diâmetro do substrato, inclinação, região da árvore (fuste; alta, média e baixa copa), tipo de substrato (bifurcação, cavidade e casca) e espécie. Análises detalhadas de distribuição ao longo das variáveis foram feitas para as 5 espécies mais abundantes: Microgramma squamulosa(75 indivíduos), Rhipsalis baccifera (67), Pleopeltis astrolepis (57), Aechmea bromeliifolia (52) e Polypodium hirsutissimum (45). O tamanho da árvore é positivamente correlacionado com a quantidade de epífitas que suporta. Há grandes variações entre as espécies arbóreas neste sentido. P. rohrii e Casearia sylvestris são as que suportam maiores quantidades de epífitas por indivíduo. As variáveis ligadas à árvore (espécie, DAP, estádio sucessional,subárea, presença ou ausência de lianas) parecem não influir na composição epifítica sobre ela. As epífitas apresentam ampla distribuição vertical e ao longo de diâmetros de substrato, com grande sobreposição entre as espécies e conseqüente ausência de estratificação. A. bromeliifolia apresentou preferência de estabelecimento em cavidades. A baixa copa e o fuste são as regiões das árvores com maior quantidade de epífitas. De forma geral, as epífitas têm preferência por alturas médias dentro da floresta (ca. 8 m), diâmetros grandes (10-30 cm), inclinações horizontais a médias e positivas. R. baccifera demonstrou preferência por P. rohrii como suporte; P. hirsutissimum e P. astrolepis, por A. sidifolia. M. squamulosa é a espécie de maior dispersão considerando-se todas as variáveis. / This work assesses floristics and structure of epiphytes, here defined as vascular plants usually found living on others, without parasitizing them, during at least a part of their life cycles. The study site, the reserve of the Cidade Universitária "Armando de Salles Oliveira" (nearly 46o43’W, 23o33’S), in São Paulo-SP (Brazil), is a secondary forested area isolated in urban environment and represents one of the few forested areas in this city. The climate type is Köppen’s Cwa, the mean annual temperature is 19,2 oC and the mean annual precipitation is 1207 mm. Polypodiaceae (9 species), Bromeliaceae (8), Orchidaceae (6), Moraceae (5), Araceae (4), Cactaceae (3), Piperaceae (1), Blechnaceae(1) and Araliaceae (1) are the families of epiphytes found at the study site, making up 38 species, 3 of them being exotic. Epiphytes are 12% of the vascular plant species cited for the reserve. This species richness is larger than expected in face of the little mean annual precipitation. All main epiphytic life forms are represented. The structure of the epiphyte community upon all the trees with girth of trunk at the height of 1,30 m (GBH) with more than 40 cm was studied in a 2000 m2 plot inside the reserve. The trees’ location inside the plot was mapped and species, height, GBH and presence/absence of lianas were recorded for each of them. From 86 trees, 29 were of Alchornea sidifolia, 10 of Croton floribundus and 8 of Piptadenia gonoacantha, the most abundant species. Pterocarpus rohrii, Rollinia sylvatica and Myrcia tenuivenosa are cited for the first time for the reserve. Two different subareas could be distinguished inside the plot as to the successional stage of the trees, an evidence for the mosaic character of the vegetation. DBH frequency distributions predict the decline of the most abundant species populations and consequent deep changes in the structure of the forest. A total census of the epiphytic stands more than 15 cm long was made upon all sampled trees. A stand was defined as a compact group of plants well separated from conspecifics. 380 stands were found, on 58 trees(67% of total). For each stand, height of attachment, branch or trunk diameter, inclination, height zone (trunk, lower, middle or upper crown), type of substrate (hole, fork or bark) and epiphyte species were recorded. The five more abundant species were analysed as to the distribution along the variables. They were: Microgramma squamulosa (75 stands), Rhipsalis baccifera (67), Pleopeltis astrolepis (57), Aechmea bromeliifolia (52) and Polypodium hirsutissimum (45). Tree height and DBH were positively correlated with number of stands and number of epiphyte species. There is great variability between tree species in these aspects. P. rohrii and Casearia sylvestris are the species with highest numbers of stands per tree. Tree characteristics such as species, DBH, successional stage, successional vegetation stage and presence/absence of lianas don’t seem to have influence on epiphyte composition on them. Epiphytes show broad vertical and diameter distributions. Species’ vertical and diameter distributions overlap largely and, as a consequence, there is no distinct stratification. A. bromeliifolia showed preference for establishment in holes. Lower crown and trunk were the zones with the largest number of stands. Epiphytes as a whole show preference for middle heights in the forest (ca. 8 m), large diameters (10-30 cm), horizontal to middle and positive inclinations. R. baccifera showed preference for P. rohrii as support tree; P. hirsutissimum and P. astrolepis showed preference for A. sidifolia. M. squamulosa is the most ubiquituous epiphytic analyzed species.

A deficiência generalizada de fósforo (P) na maioria dos solos brasileiros justifica a necessidade de adubações constantes para suprir a falta deste nutriente. Os fertilizantes totalmente acidulados, apresentando elevada solubilidade em água, são as fontes mais utilizadas na agricultura brasileira. Devido à depleção gradual das rochas fosfáticas de boa qualidade e pureza, faz-se necessário o uso de minérios considerados marginais. Uma das consequências da utilização de rochas fosfáticas contendo impurezas é a presença de compostos insolúveis nos fertilizantes, o que não representa necessariamente prejuízo ao desempenho agronômico. Porém, exigências quanto à solubilidade faziam com que estes fertilizantes contendo impurezas insolúveis não se enquadrassem à legislação. Com o objetivo de avaliar a eficiência agronômica destes fertilizantes com solubilidade variada foram realizados experimentos de incubação, de casa de vegetação e em condições de campo. O experimento de incubação foi conduzido em condições controladas com a aplicação de grânulos de sete fertilizantes testados no centro de placas de petri preenchidas com Neossolo Quartzarênico álico (RQa) com variações no pH e na capacidade de adsorção de P. Os fertilizantes testados foram: fosfato monoamônico (MAP), Fosfato diamônico (DAP), Superfosfato triplo (TSP), Superfosfato simples (SSPS), Fosfato acidulado sulfúrico (FAS), Fertilizante de rizosfera controlada (FRC) e Fosfato de solubilidade reduzida (FSR). Após cinco semanas de incubação, o solo foi amostrado na forma de anéis concêntricos, iniciando pelo centro para a avaliação da difusão do P. Grande parte do P adicionado permaneceu no próprio grânulo ou na região ao seu redor, independente do fertilizante. A maior difusão foi observada para os fosfatos de amônio. No experimento de casa de vegetação, também com RQa, avaliou-se milho por dois cultivos consecutivos com três fertilizantes com composição similar ao superfosfato simples (fonte padrão, fi > 85%), diferindo deste apenas na solubilidade em água (fi), que era de 50%, 60% e 70%. A eficiência agronômica não foi influenciada pela solubilidade destes fertilizantes, sendo que na maioria das condições de solo testadas, fertilizantes com menor solubilidade foram tão eficientes quanto o fertilizante padrão (mais solúvel). No experimento de campo, cultivando-se soja em um Latossolo Vermelho distrófico (LVd) em Itiquira, Mato Grosso, foram testados os mesmos quatro fertilizantes utilizados no experimento de casa de vegetação, tendo o SSP como fonte padrão. As fontes com solubilidade de 60% e 70% apresentaram eficiência agronômica igual ou até superior ao SSP, indicando a adequação destas fontes para o uso no campo. Estes resultados contrariam a antiga premissa de que solubilidade em água está sempre associada à eficiência agronômica. Fertilizantes fosfatados acidulados que apresentam compostos insolúveis podem apresentar desempenho agronômico equivalente a aqueles fertilizantes com elevada solubilidade em água, porém não é possivel generalizar completamente esta premissa devido às particularidades destas frações insolúveis. / The generalized deficiency of phosphorus (P) in most of the Brazilian soils justifies the need for constant fertilization in order to supply the lack of this nutrient. Fully acidulated fertilizers are the most used sources in Brazilian agriculture, with high water solubility. Due to the gradual depletion of high quality and pure phosphate ores, it is necessary to use ores considered as marginal grade. One consequence of the use of phosphate rocks containing impurities is the presence of insoluble compounds in the acidulated fertilizer, which not necessarily mean a problem to their agronomic performance. However, requirements regarding high solubility meant that these fertilizers containing insoluble impurities did not fit the law requirements. Aiming to evaluate the agronomic effectiveness of these fertilizers varying in solubility, experiments were performed under incubation, greenhouse, and field conditions. The incubation experiment was carried out under controlled environment applying seven kinds of fertilizer granules at the center of petri dishes filled up with a Quartzipsamments varying in pH and P adsorption capacity. The fertilizers tested were: monoammonium phosphate (MAP), diammonium phosphate (DAP), triple superphosphate (TSP), single superphosphate (SSP), sulfuric acidulated phosphate (FAS), rhizosphere-controlled fertilizer (RCF) and reduced solubility phosphate (FSR). After five weeks of incubation, soil was sampled as concentric rings, starting from the center section to evaluate P diffusion. Much of the added P remained in the granule itself or in the region around it, regardless of fertilizer. The higher diffusion was observed for ammonium phosphates. In a greenhouse experiment, maize was grown for first and residual yield, to evaluate three fertilizer with composition very similar to single superphosphate (standard source, fi > 85%), differing only by its water solubility, ranging from 50% to 70%. The agronomic effectiveness was not influenced by the solubility of these fertilizers. Under some soil conditions, lower solubility fertilizers were even more efficient than standard fertilizer, which had the highest solubility among all sources tested. A field experiment was carried out with soybean in Itiquira, Mato Grosso, under clayey Typic Hapludox. We also tested the four fertilizers used in the previous experiments, using single superphosphate as standard source. Sources with 60% and 70% of solubility were as efficient as single superphosphate, indicating their suitability for use in the soybean under field conditions. These results contradict the old premise that water solubility is always associated with agronomic effectiveness. Acidulated phosphate fertilizers which have insoluble compounds may exhibit agronomic performance equivalent to those fertilizers with high water solubility, however it is not possible to generalize completely this premise because of the peculiarities of these insoluble fractions.