885 resultados para Study sites


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Ciências Biológicas (Zoologia) - IBB

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

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The Amazon River floodplain is an important source of atmospheric CO2 and CH4. Aquatic herbaceous vegetation (macrophytes) have been shown to contribute significantly to floodplain net primary productivity (NPP) and methane emission in the region. Their fast growth rates under both flooded and dry conditions make herbaceous vegetation the most variable element in the Amazon floodplain NPP budget, and the most susceptible to environmental changes. The present study combines multitemporal Radarsat-1 and MODIS images to monitor spatial and temporal changes in herbaceous vegetation cover in the Amazon floodplain. Radarsat-1 images were acquired from Dec/2003 to Oct/2005, and MODIS daily surface reflectance products were acquired for the two cloud-free dates closest to each Radarsat-1 acquisition. An object-based, hierarchical algorithm was developed using the temporal SAR information to discriminate Permanent Open Water (OW), Floodplain (FP) and Upland (UL) classes at Level 1, and then subdivide the FP class into Woody Vegetation (WV) and Possible Macrophytes (PM) at Level 2. At Level 3, optical and SAR information were combined to discriminate actual herbaceous cover at each date. The resulting maps had accuracies ranging from 80% to 90% for Level 1 and 2 classifications, and from 60% to 70% for Level 3 classifications, with kappa values ranging between 0.7 and 0.9 for Levels 1 and 2 and between 0.5 and 0.6 for Level 3. All study sites had noticeable variations in the extent of herbaceous cover throughout the hydrological year, with maximum areas up to four times larger than minimum areas. The proposed classification method was able to capture the spatial pattern of macrophyte growth and development in the studied area, and the multitemporal information was essential for both separating vegetation cover types and assessing monthly variation in herbaceous cover extent.

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The phenology, flower morphology, pollination mechanism and reproductive biology of Epidendrum secundum were studied in a semi-deciduous forest at the Serra do Japi (SJ), and in the Atlantic rain forest of Picinguaba, both natural reserves in the State of Sao Paulo, southeastern Brazil. E. secundum flowers all year round, with a flowering peak between September and January. This species is either a lithophytic or terrestrial herb in the SJ, whereas, in Picinguaba, it grows mainly in disturbed areas along roadsides. E. secundum is pollinated by several species of diurnal Lepidoptera at both study sites. In Picinguaba, where E. secundum is sympatric with E. fulgens and both share the same pollinators, pollen transference between these two species was recorded. E. secundum is self-compatible but pollinator-dependent. It is inter-compatible with E. fulgens, producing fertile seeds. In contrast to the population of the SJ, in the Picinguaba region, floral morphology is quite variable among plants and some individuals present flowers with characteristics in-between both sympatric species, suggesting that natural hybridization occasionally occurs. The anthropogenic perturbation is probably the cause of the occurrence of E. secundum in the Picinguaba region, enabling its contact with E. fulgens.

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The black-tufted-marmoset (Callithrix penicillata), abundant in the southeastern state of São Paulo, is an exotic and invasive species . The present study aimed to study the behavior and make monitoring a population black-tufted-marmoset in man-made environment. The observations were made following the method of scan sampling, which consists of continuous observations with a duration of three minutes with a fifteen-minute intervals between one record and another. The individuals are monitored at two locations on campus, where two groups were identified (with a mean of 3.50 ± 2.06 individuals) totaling 291 hours and 30 minutes of observation. Were determined tree layers used, and observed that the group of EC preferably utilizes the highest stratum, while the group of LCF uses the middle and lower strata. Types of vocalization, such as calling, interaction and alert and frequency and percentage of these were also observed. The food items consumed by the groups that are similar in the two study sites, mostly sap and leaves were diagnosed. From observations of behavioral patterns was possible to construct an ethogram of the species ' Luiz de Queiroz ' campus, comprising the behaviors of vocalization, locomotion, foraging, game, among others. The results may be useful for development of management techniques and for subsequent studies

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Matemática em Rede Nacional - IBILCE

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Raccoons are the reservoir for the raccoon rabies virus variant in the United States. To combat this threat, oral rabies vaccination (ORV) programs are conducted in many eastern states. To aid in these efforts, the genetic structure of raccoons (Procyon lotor) was assessed in southwestern Pennsylvania to determine if select geographic features (i.e., ridges and valleys) serve as corridors or hindrances to raccoon gene flow (e.g., movement) and, therefore, rabies virus trafficking in this physiographic region. Raccoon DNA samples (n = 185) were collected from one ridge site and two adjacent valleys in southwestern Pennsylvania (Westmoreland, Cambria, Fayette, and Somerset counties). Raccoon genetic structure within and among these study sites was characterized at nine microsatellite loci. Results indicated that there was little population subdivision among any sites sampled. Furthermore, analyses using a model-based clustering approach indicated one essentially panmictic population was present among all the raccoons sampled over a reasonably broad geographic area (e.g., sites up to 36 km apart). However, a signature of isolation by distance was detected, suggesting that widths of ORV zones are critical for success. Combined, these data indicate that geographic features within this landscape influence raccoon gene flow only to a limited extent, suggesting that ridges of this physiographic system will not provide substantial long-term natural barriers to rabies virus trafficking. These results may be of value for future ORV efforts in Pennsylvania and other eastern states with similar landscapes.

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Prairie dog (Cynomys ludovicianus) control has historically consisted of lethal methods to maintain, reduce, or eliminate populations in South Dakota and throughout the species range. Non-lethal methods of control are desired to meet changing management objectives for the black-tailed prairie dog. The use of naturally occurring buffer strips as vegetative barriers may be effective in limiting prairie dog town expansion. The objectives of this study were: 1) to evaluate effective width of vegetative barriers in limiting prairie dog towns expansion in western South Dakota; and 2) to document effect native vegetation height on expansion of prairie dog towns in western South Dakota. Five study sites were established in western South Dakota on rangelands containing prairie dog towns of adequate size. Electric fences were constructed for the purpose of excluding cattle and creating buffer strips of native grasses and shrubs. Prairie dogs were poisoned to create a prairie dog free buffer zone adjacent to active prairie dog towns. Grazing was allowed on both sides of the buffer strip. When grazing pressure was not sufficient, mowing was used to simulate grazing. Buffer strips were 100 meters long and 10, 25, and 40 meters in width. A zero meter control was included on all study sites. Quadrats (25) were randomly distributed throughout the buffer strips. Evaluation of study sites included visual obstruction, vegetation cover, vegetation frequency, vegetation height, and vegetation identification. Barrier penetration was evaluated by the presence of new active burrows behind vegetative barriers. Significant relationships were documented for both VOR and vegetation height. No significant difference was found between frequency of breakthroughs and buffer widths.

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Because of their learned avoidance of humans and the dense cover provided by forested areas, observation of coyote activity is often very limited in the Southeast. In this study we used digital motion-sensor cameras to detect activity among coyote populations in various urban and rural habitats. Camera stations were placed adjacent to regenerating clear cuts, forest trails and roads, agriculture fields, residential areas, and within city parks to determine activity and presence of coyotes in these various areas. Cameras were successful in detecting coyotes in all study sites throughout the year. Coyotes appear to show no avoidance of camera stations. Cameras may be helpful in gathering general biological and activity information on coyote populations in an area.

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The marine environment is constantly affected by anthropic actions, with causes consequent degradation of the waters and marine biota by various discharges of xenobiotics. In the present study, the focus was the study of a region of the marine coast of the State of So Paulo (city of Santos), which is one of the most industrialized parts of Brazil and suffers also from a strong impact of domestic effluents. The mussel Perna perna, very abundant in the coast of the State of So Paulo, Brazil, was selected as the biomonitoring organism for the determination of inorganic elements and a passive biomonitoring was performed. The organisms were collected at two sites in So Paulo State coast: Cocanha beach in Caraguatatuba (mussel farm) and Santos Bay (Itaipu and Palmas). Seasonally, the Perna perna were collected between September/08 and July/09 in each study sites. After removal and sample preparation, the elements As, Co, Cr, Fe, Se and Zn were determined by instrumental neutron activation analysis (INAA) and Cd, Pb and Hg were determined by atomic absorption spectroscopy (AAS) in this organism.

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The rainforest of Mexico has been degraded and severely fragmented, and urgently require restoration. However, the practice of restoration has been limited by the lack of species-specific data on survival and growth responses to local environmental variation. This study explores the differential performance of 14 wet tropical early-, mid- or late-successional tree species that were grown in two abandoned pastures with contrasting land-use histories. After 18 months, seedling survival and growth of at least 7 of the 14 tree species studied were significantly higher in the site with a much longer history of land use (site 2). Saplings of the three early-successional species showed exceptional growth rates. However, differences in performance were noted in relation to the differential soil properties between the experimental sites. Mid-successional species generally showed slow growth rates but high seedling survival, whereas late-successional species exhibited poor seedling survival at both the study sites. Stepwise linear regressions revealed that the species integrated response index combining survivorship and growth measurements, was influenced mostly by differences in soil pH between the two abandoned pastures. Our results suggest that local environmental variation among abandoned pastures of contrasting land-use histories influences sapling survival and growth. Furthermore, the similarity of responses among species with the same successional status allowed us to make some preliminary site and species-specific silvicultural recommendations. Future field experiments should extend the number of species and the range of environmental conditions to identify site generalists or more narrowly adapted species, that we would call sensitive.