Foraging strategies and reproductive success in two sympatric seabird species: influence of environmental variability

 This work focused on flexibility in foraging strategies in little penguins and short-tailed shearwaters, which represents an important mechanism enabling them to cope with highly dynamic ecosystems and provides a buffer against spatial and temporal changes in prey availability over the breeding period.

Assessing spatio-temporal hydrologic variability: a case-study in western Victoria

This research explored spatial and temporal variability in the relationships between land cover, topography, and climate on streamflows and wetland extents in western Victoria.

Holocene record of Tuggerah Lake estuary development on the Australian east coast: sedimentary responses to sea-level fluctuations and climate variability

We investigated the Holocene palaeo-environmental record of the Tuggerah Lake barrier estuary on the south-east coast of Australia to determine the influence of local, regional and global environmental changes on estuary development. Using multi-proxy approaches, we identified significant down-core variation in sediment cores relating to sea-level rise and regional climate change. Following erosion of the antecedent land surface during the post-glacial marine transgression, sediment began to accumulate at the more seaward location at ~8500. years before present, some 1500. years prior to barrier emplacement and ~4000. years earlier than at the landward site. The delay in sediment accumulation at the landward site was a consequence of exposure to wave action prior to barrier emplacement, and due to high river flows of the mid-Holocene post-barrier emplacement. As a consequence of the mid-Holocene reduction in river flows, coupled with a moderate decline in sea-level, the lake experienced major changes in conditions at ~4000. years before present. The entrance channel connecting the lake with the ocean became periodically constricted, producing cyclic alternation between intervals of fluvial- and marine-dominated conditions. Overall, this study provides a detailed, multi-proxy investigation of the physical evolution of Tuggerah Lake with causative environmental processes that have influenced development of the estuary.

Step by step analyzing, modeling and simulation of single and double array PV system in different environmental variability

This research analyses the mathematical model of the PV array with all the parameters involved, in the sequential steps. Then it is going to simulate the I-V and P-V characteristics of PV array in different climatology conditions, by using both MATLAB M-file and Simulink. Finally the capability of this method is demonstrated in simulated results, which are performed for both Single and Double Array PV system.

Variability of sedimentary organic carbon in patchy seagrass landscapes

Seagrass ecosystems, considered among the most efficient carbon sinks worldwide, encompass a wide variety of spatial configurations in the coastal landscape. Here we evaluated the influence of the spatial configuration of seagrass meadows at small scales (metres) on carbon storage in seagrass sediments. We intensively sampled carbon stocks and other geochemical properties (δ(13)C, particle size, depositional fluxes) across seagrass-sand edges in a Zostera muelleri patchy seagrass landscape. Carbon stocks were significantly higher (ca. 20%) inside seagrass patches than at seagrass-sand edges and bare sediments. Deposition was similar among all positions and most of the carbon was from allochthonous sources. Patch level attributes (e.g. edge distance) represent important determinants of the spatial heterogeneity of carbon stocks within seagrass ecosystems. Our findings indicate that carbon stocks of seagrass areas have likely been overestimated by not considering the influence of meadow landscapes, and have important relevance for the design of seagrass carbon stock assessments.

Whistle variability in South Atlantic spinner dolphins from the Fernando de Noronha Archipelago off Brazil

A series of quali- and quantitative analyses were conducted to evaluate the variability of spinner dolphin whistles from the Fernando de Noronha Archipelago off Brazil. Nine variables were extracted from each whistle contour, and the whistle contours shapes were classified into the seven categories described in Driscoll (1995). The analysis showed mean beginning and ending frequencies values of 10.78 and 12.74 kHz, respectively. on average, whistle duration was relatively short, with mean values around 0.495 s (N=702). Comparative analyses were also conducted to investigate the relationship between the obtained results and those presented in previous studies. When comparing averages, the results of the study of Oswald et al. (2003) in the Tropical Eastern Pacific (TEP) presented less significant differences in relation to this study; only whistle duration differed significantly between both works. The results of multivariate classification tests also pointed TEP population as the closest related to the population studied here. The similarities between such disjunct populations might be attributed to a more recent isolation event (the closing of the Panama Isthmus) than the divergence that has driven North and South Atlantic populations apart. (c) 2006 Acoustical Society of America.

Environmental and grazing influence on spatial variability of intertidal biofilm on subtropical rocky shores

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

BIOCHEMICAL VARIABILITY BETWEEN VENOMS FROM DIFFERENT HONEYBEE (APIS-MELLIFERA) RACES

1. The comparison of molecular exclusion cromatography profiles of venoms from sting apparatuses of Apis mellifera ligustica, Apis mellifera adansonii and Africanized honey-bees in Sephadex G-100 revealed both qualitative and quantitative differences.2. The venoms from A.m. ligustica and A.m. adansonii presented, respectively, three and two peaks characteristic of each sub-species, while Africanized honey-bee was characterized by the absence of eight peaks common to the former.3. The polypeptides with M(r) in the range from 100,000 to 7500 da correspond respectively to 62.0%, 66.6% and 68.7% of total proteins from the venon of A.m. ligustica, A.m. adansonii and Africanized honey-bees, while the peptidic fraction with M(r) range from 4100 to 2000 da corresponds to 11.4%, 32.4% and 10.2% of venom protein, respectively.

Characterization of the genetic variability among Caesalpinia pulcherrima (L.) Sw. (Fabaceae) plants using RAPD molecular markers

O flamboyanzinho (Caesalpinia pulcherrima, Fabaceae) é muito utilizado como cerca-viva e na arborização de ruas, parques e jardins. de florescimento exuberante, suas flores podem apresentar coloração rosa, laranja ou amarela, conforme a variedade. Como características florais são essenciais para a definição do valor comercial de espécies ornamentais, o objetivo principal do trabalho foi verificar a existência de polimorfismo entre plantas de C. pulcherrima, que produzem flores de diferentes colorações, por marcadores moleculares RAPD. Foram escolhidas aleatoriamente 30 plantas adultas, cultivadas no município de Jaboticabal, Estado de São Paulo, para a retirada de amostras foliares para a extração de DNA. Dentre essas matrizes, 20 possuem flores alaranjadas, oito, flores amarelas, e apenas duas produzem flores de coloração rosa. Dos 140 primers de RAPD avaliados, 94 foram capazes de ampliar fragmentos definidos, gerando 246 bandas, das quais se observou 100% de bandas monomórficas, indicando que nenhum dos primers utilizados detectou polimorfismo entre os tratamentos. Concluiu-se que a técnica para detecção de polimorfismo por marcadores RAPD não foi eficiente, e que existe a necessidade de se testarem marcadores moleculares mais específicos. Além disso, a característica morfológica cor de flor é, possivelmente, controlada por vários genes ou pela combinação deles.

Soil texture spatial variability of different parent material in pereira barreto, São Paulo state

The variation of soil textural characteristics is a function of the relief and parent materials. The objective of this work was to study soil texture spatial variability from different parent material in Pereira Barreto, SP. An area of 530.67 hectares was mapped through the use of Global Positioning System receivers and obtaining of Digital Elevation Models. A set of 201 soil samples was collected from every seven hectares, at three depths: 0 - 0.25 m; 0.25 - 0.50 m; and 0.80 - 1.00 m. The amounts of sand, silt and clay were obtained by the pipette method and analyzed by both descriptive statistics and geostatistics. Soil textures varied as a function of parent materials and topography.

Spatial variability of soil CO2 emission in a sugarcane area characterized by secondary information

Soil CO2 emission (FCO2) is governed by the inherent properties of the soil, such as bulk density (BD). Mapping of FCO2 allows the evaluation and identification of areas with different accumulation potential of carbon. However, FCO2 mapping over larger areas is not feasible due to the period required for evaluation. This study aimed to assess the quality of FCO2 spatial estimates using values of BD as secondary information. FCO2 and BD were evaluated on a regular sampling grid of 60 m × 60 m comprising 141 points, which was established on a sugarcane area. Four scenarios were defined according to the proportion of the number of sampling points of FCO2 to those of BD. For these scenarios, 67 (F67), 87 (F87), 107 (F107) and 127 (F127) FCO2 sampling points were used in addition to 127 BD sampling points used as supplementary information. The use of additional information from the BD provided an increase in the accuracy of the estimates only in the F107, F67 and F87 scenarios, respectively. The F87 scenario, with the approximate ratio between the FCO2 and BD of 1.00:1.50, presented the best relative improvement in the quality of estimates, thereby indicating that the BD should be sampled at a density 1.5 time greater than that applied for the FCO2. This procedure avoided problems related to the high temporal variability associated with FCO2, which enabled the mapping of this variable to be elaborated in large areas.

Spatial variability of physical attributes of an alfisol under different hillslope curvatures

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)