Observation of floral visitation is an accepted method to describe plant-pollinator interactions despite potential biases. Collecting pollen from pollinators offers new insights on the structure and function of plant-pollinator communities. Furthermore, the strength and frequency of plant-pollinator interactions can vary across temporal scales. However, within-season and within-day (morning vs. evening) variation in plant-pollinator networks has been little studied. By evaluating variation in network structure across these biologically relevant time scales, we will gain a better understanding of the factors that shape plant-pollinator communities. The objectives of this study are to 1) Compare the structure of plant-pollinator networks built on floral visitation and pollen transport data, 2) Evaluate intra-annual variation in plant-pollinator network structure and 3) Evaluate variation in plant-pollinator structure within a single day (i.e. morning vs. evening). Congruence and Temporal Variation of Floral Visitation and Pollen Transport Networks in Southern Appalachia

Based on the concentrations of ten heavy metals (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn, Fe) in 144 road dust samples collected from 36 sites across 4 seasons from 2016 to 2017 in Beijing, this study systematically analyzed the levels and main sources of health risks in terms of their temporal and spatial variations. A combination of receptor models (positive matrix factorization and multilinear engine-2), human health risk assessment models, and Monte Carlo simulations were used to apportion the seasonal variation of the health risks associated with these heavy metals. While non-carcinogenic risks were generally acceptable, Cr and Ni induced cautionary carcinogenic risks (CR) to children (confidence levels was approximately 80% and 95%, respectively). Additionally, fuel combustion posed cautionary CR to children in all seasons, while the level of CR from other sources varied, depending on the seasons. Heavy metal concentrations were the most influential variables for uncertainties, followed by ingestion rate and skin adherence factor. The values and spatial patterns of health risks were influenced by the spatial pattern of risks from each source.

Marine communities are affected by oceanographic processes, which influence ecological interactions, such as recruitment rates, that are essential regulators of community dynamics. These relationships are not constant; they change in space and time or among taxa. We defend the thesis that oceanographic processes of climatic origin influencing larval abundance at the study region, regulate and establish the trends in settlement and recruitment of invertebrates (cirripeds and bivalves) at rocky shore intertidal. We first investigated the recruitment at different temporal scales and its relationships with physical forcings, chlorophyll-a concentration and sea surface temperature. Second, we focused on the spatial synchrony and contrasts of recruitment, and interspecific trends. Third, we described and evaluated the co-variation between cold fronts and the larval abundance and settlement. We concluded that there is a high degree of correlation between recruitment/settlement and the variation of the wind field, which set temporal trends. Cold fronts are important regulators of settlement, but higher recruitment was associated to NE-E winds. Barnacle recruitment is more susceptible to the environmental variations compared to bivalves. Regional recruitment is not spatially synchronic with differences in the scale of 100 km. This study highlights the importance of oceanic-climatic phenomena as predictors of spatio-temporal trends of recruitment showing that climatic fluctuations might have contrasting effects on rocky shore communities. / As comunidades marinhas são afetadas por processos oceanográficos que influenciam as interações ecológicas, como as taxas de recrutamento, reguladores essenciais da dinâmica dessas comunidades. Essas relações não são constantes, elas mudam no espaço e no tempo, ou entre taxa. Aqui nós defendemos a tese que processos oceanográficos de origem climática, por influenciarem a abundância larval região de estudo, regulam e estabelecem tendências do assentamento e recrutamento de invertebrados (cirripedes e bivalves) do entremarés de costas rochosas. Primeiramente, nós investigamos o recrutamento em diferentes escalas de tempo e sua relação com forçantes físicas, concentração de clorofila-a e temperatura da superfície do mar. Em um segundo momento, nós focamos na sincronia e nos contrastes espaciais do recrutamento, e as tendências inter-específicas. Por fim, descrevemos e avaliamos a co-variância entre frentes frias, abundância larval e assentamento. Concluímos que há um alto grau de correlação entre recrutamento/ assentamento e a variação do campo de ventos, o qual estabelece as tendências temporais. As frentes frias são reguladores importantes do assentamento, mas o recrutamento mais alto está associado a ventos de NE-E. O recrutamento de cirripedes é mais susceptível às variações ambientais se comparado aos bivalves. O recrutamento regional não é sincrônico no espaço, com diferenças na escala de 100km. Este estudo destaca a importância dos fenômenos oceano-climáticos na previsão de tendências espaço-temporais do recrutamento, mostrando que flutuações climáticas podem ter efeitos contrastantes nas comunidades de costas rochosas.

Marine communities are affected by oceanographic processes, which influence ecological interactions, such as recruitment rates, that are essential regulators of community dynamics. These relationships are not constant; they change in space and time or among taxa. We defend the thesis that oceanographic processes of climatic origin influencing larval abundance at the study region, regulate and establish the trends in settlement and recruitment of invertebrates (cirripeds and bivalves) at rocky shore intertidal. We first investigated the recruitment at different temporal scales and its relationships with physical forcings, chlorophyll-a concentration and sea surface temperature. Second, we focused on the spatial synchrony and contrasts of recruitment, and interspecific trends. Third, we described and evaluated the co-variation between cold fronts and the larval abundance and settlement. We concluded that there is a high degree of correlation between recruitment/settlement and the variation of the wind field, which set temporal trends. Cold fronts are important regulators of settlement, but higher recruitment was associated to NE-E winds. Barnacle recruitment is more susceptible to the environmental variations compared to bivalves. Regional recruitment is not spatially synchronic with differences in the scale of 100 km. This study highlights the importance of oceanic-climatic phenomena as predictors of spatio-temporal trends of recruitment showing that climatic fluctuations might have contrasting effects on rocky shore communities. / As comunidades marinhas são afetadas por processos oceanográficos que influenciam as interações ecológicas, como as taxas de recrutamento, reguladores essenciais da dinâmica dessas comunidades. Essas relações não são constantes, elas mudam no espaço e no tempo, ou entre taxa. Aqui nós defendemos a tese que processos oceanográficos de origem climática, por influenciarem a abundância larval região de estudo, regulam e estabelecem tendências do assentamento e recrutamento de invertebrados (cirripedes e bivalves) do entremarés de costas rochosas. Primeiramente, nós investigamos o recrutamento em diferentes escalas de tempo e sua relação com forçantes físicas, concentração de clorofila-a e temperatura da superfície do mar. Em um segundo momento, nós focamos na sincronia e nos contrastes espaciais do recrutamento, e as tendências inter-específicas. Por fim, descrevemos e avaliamos a co-variância entre frentes frias, abundância larval e assentamento. Concluímos que há um alto grau de correlação entre recrutamento/ assentamento e a variação do campo de ventos, o qual estabelece as tendências temporais. As frentes frias são reguladores importantes do assentamento, mas o recrutamento mais alto está associado a ventos de NE-E. O recrutamento de cirripedes é mais susceptível às variações ambientais se comparado aos bivalves. O recrutamento regional não é sincrônico no espaço, com diferenças na escala de 100km. Este estudo destaca a importância dos fenômenos oceano-climáticos na previsão de tendências espaço-temporais do recrutamento, mostrando que flutuações climáticas podem ter efeitos contrastantes nas comunidades de costas rochosas.

<p>Plant-animal interactions are affected by both abundance and distribution of interacting species and the community context in which they occur. However, the relative importance of these factors is poorly known. I examined the effects of predator host range, environmental factors, host plant populations, plant traits and fruit abortion on the intensity of pre-dispersal seed predation in 46 host populations of the perennial herb <i>Lathyrus vernus</i>. I recorded damage by beetle pre-dispersal seed predators, mainly <i>Apion opeticum </i>and <i>Bruchus atomarius</i> with different host ranges on <i>L. vernus</i> as well as on two additional host plants. Local seed predator population size was mainly influenced by plant population size, current seed production and beetle population size in the previous year, but was not strongly affected by connectivity. The monophagous seed predator was less abundant and had lower densities than the oligophagous. Both predator species had a strong ability to track fluctuations in seed production; intensity of predation increased with relative increases in seed production. Oligophagous predation on<i> L. vernus i</i>ncreased with the abundance of alternative hosts, but presence of<i> L. vernus</i> did not affect predation on alternative hosts. Abundances and trait preferences differed among three co-occurring seed predators, but were also associated with the abundance of the other species. Overall, seed predation influenced selection on flower number. I found clear indications of seed predator offence but no obvious plant defence. The pattern of fruit abortion was associated with reduced plant fitness since the seed predator had an advanced ability to locate fruits with high probability of retention. Taken together, different factors influencing abundance of the seed predator species, different preferences, and context dependent trait selection are likely to result in complex spatio-temporal variation in overall seed losses and trait selection in the common host plant.</p>

Plant-animal interactions are affected by both abundance and distribution of interacting species and the community context in which they occur. However, the relative importance of these factors is poorly known. I examined the effects of predator host range, environmental factors, host plant populations, plant traits and fruit abortion on the intensity of pre-dispersal seed predation in 46 host populations of the perennial herb Lathyrus vernus. I recorded damage by beetle pre-dispersal seed predators, mainly Apion opeticum and Bruchus atomarius with different host ranges on L. vernus as well as on two additional host plants. Local seed predator population size was mainly influenced by plant population size, current seed production and beetle population size in the previous year, but was not strongly affected by connectivity. The monophagous seed predator was less abundant and had lower densities than the oligophagous. Both predator species had a strong ability to track fluctuations in seed production; intensity of predation increased with relative increases in seed production. Oligophagous predation on L. vernus increased with the abundance of alternative hosts, but presence of L. vernus did not affect predation on alternative hosts. Abundances and trait preferences differed among three co-occurring seed predators, but were also associated with the abundance of the other species. Overall, seed predation influenced selection on flower number. I found clear indications of seed predator offence but no obvious plant defence. The pattern of fruit abortion was associated with reduced plant fitness since the seed predator had an advanced ability to locate fruits with high probability of retention. Taken together, different factors influencing abundance of the seed predator species, different preferences, and context dependent trait selection are likely to result in complex spatio-temporal variation in overall seed losses and trait selection in the common host plant.

The seasonal variation and landscape regulation of dissolved organic carbon (DOC) concentrations in streams have been studied in two watersheds in the boreal zone. The seasonal variation was found to be highly correlated to variations in runoff. An increase in runoff was always accompanied with an increase in DOC concentration. However, there were indications that the TOC concentration was restricted by the soil TOC pool during snowmelt. The main factors affecting DOC exports varied between seasons. During winter baseflow the spatial variation in DOC exports was strongly influenced by wetland coverage, during snowmelt the exports were correlated to factors describing the size and location of the catchment, and during the snow-free season they were heavily affected by the proportions of wetlands and forests in the catchments. Small headwaters had the highest terrestrial DOC export, per unit area. The properties of the DOC changed during spring flood, towards lower molecular weight and more aliphatic compounds. These changes affected the bioavailability of the DOC, which increased during spring flood. There were also differences in the DOC properties between wetlands and forest soils; the forested soils yielded DOC with lower molecular weight (measured as 254 nm/365 nm light absorbance ratios), largely from superficial layers that were activated during high flow events, while wetland soils generally provided a more constant carbon source with higher molecular weight. The majority of the DOC was exported by wetlands, but most of the short-term bioavailable DOC (BP7) was derived from the forests, during the spring flood period, indicating that bacterial production in streams and lakes is likely to be almost entirely based on DOC exported from forested areas during, and some time after, the spring flood event.

Made available in DSpace on 2014-06-11T19:33:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-30Bitstream added on 2014-06-13T19:04:50Z : No. of bitstreams: 1 brito_lf_dr_jabo.pdf: 1108537 bytes, checksum: 980659ce6ae61be1c376f0ca8bf81d20 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A variação espacial e temporal da emissão de CO2 do solo é influenciada por atributos do solo relacionados à produção e ao transporte do gás soloatmosfera. Entretanto, ainda são escassos estudos visando compreender o efeito da topografia sobre a variabilidade da emissão de CO2 do solo, especialmente em área de conversão para o sistema de colheita da cana-de-açúcar mecanizada sem queima. Este trabalho tem como objetivo estudar as variações da emissão de CO2 do solo, em área cultivada com cana-de-açúcar, com histórico de colheita mecanizada sem queima, sob diferentes formas do relevo e posições na encosta. Foram selecionadas uma área situada numa superfície côncava (CONC) e outras duas em posições contrastantes numa superfície linear (encosta superior – ESUP e encosta inferior – EINF). Foram conduzidas avaliações da emissão de CO2 e de atributos do solo, nas três áreas, em duas situações distintas: (1) em 2004, um mês após plantio da cana-de-açúcar, foram conduzidas avaliações em pontos aleatórios em cada uma das três áreas, num mesmo dia, sendo a emissão de CO2, temperatura e umidade do solo avaliados ao longo de 7 meses e, (2) em 2005, um mês após o corte mecanizado da cana-de-açúcar crua, foi caracterizada a variabilidade espacial da emissão de CO2 e demais atributos do solo, por meio da semivariância, nas mesmas posições topográficas. A emissão total de CO2 no período de 7 meses de estudo em 2004 foi 19,26, 23,03 e 22,29 Mg CO2 ha-1 nas áreas CONC, ESUP e EINF, respectivamente. A variação temporal da emissão foi explicada por uma relação exponencial com temperatura, e uma relação linear com umidade do solo. O valor de 10 Q , calculado para as posições CONC, ESUP e EINF, foi de 1,98 (±0,34), 1,81 (±0,49) e 1,71 (±0,31). O efeito da forma do relevo e da posição topográfica sobre a variação da emissão de CO2 do... / The spatial and temporal variation of soil CO2 emission is influenced by several soil attributes related to CO2 production and gas transport from soil to atmosphere. However, few studies aiming to understand the effect of topography on the variability of CO2 emissions exist, especially on the sugarcane harvest system without prior burning. The objective of this work was to study the spatial and temporal changes of the soil CO2 emission in an area cultivated with sugar cane, having a mechanized crop system, under different relief forms and slope positions. In a landscape it was selected one area located in a concave form (CONC) and two others located at superior (ESUP) and inferior (EINF) positions in a linear form. It was conducted measurements of soil CO2 emission and soil attributes at the three different locations in two different situations: (1) in 2004, one month after sugarcane plantation, measurements were conducted with randomized repetitions for each area in each sampling day, and soil CO2 emission, soil temperature and soil moisture were also monitored during a period of 7 months, and (2) in 2005, one month after sugarcane harvesting without burning, the spatial variability of soil CO2 emission and soil attributes were characterized by the semivariance in the same topographic positions. Total soil CO2 emission during this period was 19,26, 23,03 e 22,29 Mg CO2 ha-1 for CONC, ESUP e EINF areas, respectively. Temporal variability of soil CO2 emission was explained by an exponential function with soil temperature and a linear function with soil moisture. The 10 Q values were 1.98 (±0.34), 1.81 (±0.49) and 1.71 (±0.31) for CONC, ESUP and EINF, respectively. The effect of relief form and topographic position on soil CO2 emission variation was dependent on the time of measurement. Bulk density, macroporosity, penetration resistance, aggregation and oxidizable organic ...(Comlete abstract, click electronic access below)

Submitted by Morgana Silva (morgana_linhares@yahoo.com.br) on 2016-09-02T18:25:38Z No. of bitstreams: 1 arquivototal.pdf: 2592142 bytes, checksum: dd45efc0e1a81f0b530292f8066be45b (MD5) / Made available in DSpace on 2016-09-02T18:25:38Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2592142 bytes, checksum: dd45efc0e1a81f0b530292f8066be45b (MD5) Previous issue date: 2015-05-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Algae are some of the most important organisms in reef environments as make up the base of the food chain, act as habitat structuring and serve as potential environmental health bio-indicators. This study aimed to analyze the structure and dynamics of macroalgae assemblages in Paraíba shallow reefs and evaluate the use of these bodies / processes as a mechanism bioindicador. This work was divide into three case studies in which the structure and dynamics of macroalgae assemblage play a fundamental role. The first work aimed to know the status of the population of Gracilaria caudata J. Agardh and macroalgae community associated with the Ponta de Mato reef, Cabedelo/PB, after the overexploitation impact occurred nearly 20 years and as a comparison based on a previous database. The strong impact on the dominant population was answered replacement of species and area once dominated by G. caudata was currently dominate by Jania subulata (Ellis & Solander) Sonder and Sargassum sp. The second study aimed to assess environmental health from two reef environments subjected to different tourist pressures, Picãozinho and São Gonçalo both located in João Pessoa/PB. In areas of intense tourist activity, the algae presented with lower richness, biomass and diversity compared with areas that receive no tourists, suggesting that the environment is under the influence of disorders and stress regime. The third case study aimed to analyze the structure and dynamics of macroalgae assemblages of Formosa reef, Cabedelo/PB with a time perspective. There was temporal variation in descriptors richness and biomass, with the lowest figures recorded in August/2013 and August/2014 and the highest in February/2014 and May/14. Understanding how the impacts (natural or anthropogenic) affect the distribution and dynamics of the species is important in the selection and potential use of bio-indicator species of environmental disturbances. / As algas constituem alguns dos organismos mais importantes nos ambientes recifais, pois compõem a base da cadeia trófica, atuam como estruturadoras do habitat e servem como potenciais bioindicadoras de qualidade ambiental. Este trabalho teve por objetivo analisar a estrutura e a dinâmica de assembléias de macroalgas em ambientes recifais rasos da Paraíba e avaliar a utilização destes organismos/processos como mecanismo bioindicador. A dissertação foi dividida em três estudos de caso nos quais a estrutura e/ou dinâmica das populações e comunidade de macroalgas possuem papel fundamental: O primeiro teve por objetivos conhecer o status da população de Gracilaria caudata J. Agardh e comunidade de macroalgas associadas ao ambiente recifal de Ponta de Mato, Cabedelo/PB, após o impacto de sobreexplotação ocorrido a quase 20 anos, tendo como base de comparação um banco de dados pretéritos dessa população. O forte impacto sobre a população dominante teve como resposta a substituição de espécies e a área outrora dominada por G. caudata é atualmente dominada por Jania subulata (Ellis & Solander) Sonder e Sargassum sp. O segundo trabalho teve por objetivo avaliar a qualidade ambiental de dois ambientes recifais submetidos a diferentes pressões turísticas, Picãozinho e São Gonçalo ambos localizados no município de João Pessoa/PB. Nas áreas de intensa atividade turística, as algas apresentaram-se com riqueza, biomassa e diversidade mais baixas quando comparados com as áreas que não recebem turistas, sugerindo que o ambiente está sob efeito de distúrbios e regime de estresse. O terceiro caso de estudo teve por objetivo analisar a estrutura e a dinâmica das comunidades macrofitobênticas do recife de Formosa, Cabedelo/PB sob uma perspectiva temporal. Houve variação temporal nos descritores de riqueza e biomassa, com os valores mais baixos registrados nos meses de Agosto/2013 e Agosto/2014, e os mais altos em Fevereiro/2014 e Maio/14. O entendimento de como os impactos (naturais ou antropogênicos) afeta a distribuição e a dinâmica das espécies é importante na seleção e potencial utilização de espécies bioindicadoras de distúrbios ambientais.

Resumo: Com o objetivo avaliar a influência de doses de nitrogênio realizadas para a alface e/ou para a rúcula, em consórcio, sobre as plantas (estado nutricional e crescimento) e sobre o consórcio (produtividade, classificação e qualidade, uso eficiente da área e rentabilidade), foi realizado um experimento no período de setembro à dezembro de 2006, na Unesp, Campus de Jaboticabal-SP. O delineamento experimental foi o de blocos casualizados completos, com quatro repetições, sendo os tratamentos arranjados em esquema fatorial 4 x 4 + 2. Os tratamentos resultaram da combinação de quatro doses de N para a alface (0, 65, 130 e 195 kg/ha de N) e quatro doses de N para a rúcula (0, 65, 130 e 195 kg/ha de N), mais dois tratamentos adicionais, correspondentes às monoculturas de alface e rúcula. As cultivares utilizadas foram Verônica (alface) e Folha Larga (rúcula). Para todas as características avaliadas de plantas de alface a monocultura (testemunha) tiveram melhor desempenho que em consórcios, não ocorrendo diferenças para as características de rúcula. O aumento da dose de N para ambas as culturas, em consórcio, proporcionou incrementos nas características de plantas de alface e rúcula. A máxima produtividade de alface, 23.744,48 kg/ha, foi obtida com 100 kg/ha de N para alface e 195 kg/ha de N para rúcula. A máxima produtividade de rúcula, 14.435,78 kg/ha, foi obtida com a adubação de 195 kg/ha de alface e 180 kg/ha de N para rúcula. A maximização do índice de eficiência de uso da área (1,86) foi obtido na dose 127 kg/ha N para a alface e 195 xv kg/ha N para rúcula. O maior lucro operacional, R$ 29.026,11/ha, foi obtido na combinação de doses de 122 kg/ha N para alface e 195 kg/ha N para rúcula. / Abstract: In order to evaluate the influence how nitrogen rates used for lettuce and/or rocket, under intercropping, affect the plants (nutrition and growth conditions), and the intercropping (yielding, grading, land equivalent ratio and profitability), an experiment was carried out at the campus of Unesp in Jaboticabal-SP, from September to December 2006. The experiment was conducted in a randomized complete block design, with four replications, treatments being arranged in a 4 x 4 + 2 factorial design. The treatments were the result of a combination of four N rates for lettuce (0, 65, 130 and 195 kg/ha of N), and four N rates for rocket (0, 65, 130 and 195 kg/ha of N), plus two additional treatments, which corresponded to lettuce and rocket under single cropping. Veronica (lettuce) and Folha Larga (rocket) were the cultivars used. For all the plant characteristics of lettuce that were studied, the single cropping (witness) had better performance than in intercropping, whereas no differences were observed for the rocket characteristics. An increase in the N rate for both cultures under intercropping showed gains in the plant characteristics of lettuce and rocket. Maximum lettuce yield, 23,744.48 kg/ha, was achieved with the application of 100 kg N ha for lettuce, and 195 kg N ha for rocket. Maximum rocket yield, 14,435.78 kg/ha, was achieved with the application of 195 kg N ha for lettuce, and 180 kg N ha for rocket. The land equivalent ratio was maximized (1.86) by using 127 kg N ha for lettuce and 195 kg N ha for rocket. The highest xvii operating profit, R$ 29,026.11/ha, resulted from the combination of 122 kg N ha for lettuce and 195 kg N ha for rocket. / Orientador: Arthur Bernardes Cecílio Filho / Coorientador: Renato de Mello Prado / Coorientador: José Carlos Barbosa / Banca: Francisco Bezerra Neto / Banca: Leilson Costa Grangeiro / Banca: Domingos Fornasieri Filho / Banca: José Ricardo Mantovani / Doutor