Time filter

Source Type

Boa Vista, Brazil

Gondim Jr. M.G.C.,University of Pernambuco | Castro T.M.M.G.,State University of Roraima | Marsaro Jr. A.L.,Laboratorio Of Entomologia | Navia D.,Laboratorio Of Quarentena Vegetal | And 3 more authors.
Systematics and Biodiversity | Year: 2012

The red palm mite Raoiella indica Hirst (Tenuipalpidae) was first reported in the New World in 2004, dispersing quickly and widely while adopting new plant species as hosts. Since then, it has caused severe damage in this region, especially to coconut (Cocos nucifera L.). It was first found in Brazil in 2009, in the northern Amazonian state of Roraima. In the present study, native and introduced plants were sampled between March 2010 and February 2011 in sites of the 15 Roraima municipalities, to estimate its distribution and the associated mite fauna. In addition, monthly samples were taken from a coconut plantation in Mucajaí throughout the same period, for an initial appraisal of the levels R. indica could reach. It was found in 10 municipalities, on 19 plant species of four families. Six species are reported for the first time as hosts. Among the associated predators, 89.1% were Phytoseiidae, most commonly Amblyseius largoensis (Muma), Iphiseiodes zuluagai Denmark & Muma and Euseius concordis (Chant). The highest densities of R. indica, 1.5 and 0.35 mites/cm2 of leaflet (approx total of 331 and 77 mites/leaflet), were reached respectively in March 2010 and February 2011. The highest density of phytoseiids on coconut (0.009 mites/cm2 or about 2 mites/leaflet) was reached in November 2010. The average densities of R. indica recorded for Roraima were comparable to those reported for countries in which the mite is reportedly economically damaging. The dispersal of R. indica through the Amazon forest may result in damage to cultivated and native palms, and plants of other families, if the projected increase in both the frequency and the severity of drought events occurs. Parts of the Amazon have undergone periods of low rainfall, a condition that appears to favour the biology of this mite. Its eventual arrival to northeastern Brazil may result in heavy economic and ecological losses. © 2012 The Natural History Museum.

Barni P.E.,State University of Roraima | Pereira V.B.,Federal University of Roraima | Manzi A.O.,National Institute of Amazonian Research | Barbosa R.I.,National Institute of Amazonian Research
Environmental Management | Year: 2015

Deforestation and forest fires in the Brazilian Amazon are a regional-scale anthropogenic process related to biomass burning, which has a direct impact on global warming due to greenhouse gas emissions. Containment of this process requires characterizing its spatial distribution and that of the environmental factors related to its occurrence. The aim of this study is to investigate the spatial and temporal distribution of deforested areas and forest fires in the State of Roraima from 2000 to 2010. We mapped deforested areas and forest fires using Landsat images and associated their occurrence with two phytoclimatic zones: zone with savanna influence (ZIS), and zone without savanna influence (ZOS). Total deforested area during the interval was estimated at 3.06 × 103 km2 (ZIS = 55 %; ZOS = 45 %) while total area affected by forest fires was estimated at 3.02 × 103 km2 (ZIS = 97.7 %; ZOS = 2.3 %). Magnitude of deforestation in Roraima was not related to the phytoclimatic zones, but small deforested areas (≤17.9 ha) predominated in ZOS while larger deforestation classes (>17.9 ha) predominated in ZIS, which is an area with a longer history of human activities. The largest occurrence of forest fires was observed in the ZIS in years with El Niño events. Our analysis indicates that the areas most affected by forest fires in Roraima during 2000–2010 were associated with strong climatic events and the occurrence these fires was amplified in ZIS, a sensitive phytoclimatic zone with a higher risk of anthropogenic fires given its drier climate and open forest structure. © 2015, Springer Science+Business Media New York.

Toledo J.J.,National Institute of Amazonian Research | Toledo J.J.,State University of Roraima | Magnusson W.E.,National Institute of Amazonian Research | Castilho C.V.,EMBRAPA - Empresa Brasileira de Pesquisa Agropecuaria
Journal of Vegetation Science | Year: 2013

Questions: What processes shape the size-density distribution of tropical trees? Are these processes affected by topographic position? Location: Reserva Ducke, Central Amazonia, Manaus, Brazil. Methods: We identified tree mode of death in a 5-yr census interval (2003-2008) in 72 1-ha permanent plots distributed over 64 km2, and calculated the proportion of standing and fallen modes of deaths across size classes and by topographic position. Lowess regression was used to identify the dominance of standing or fallen modes across tree sizes. We used this information to separate the size-density distribution of trees into two parts hypothetically shaped by different processes. We fitted several models and tested the metabolic theory's prediction that size-density distribution scales with stem diameter to the -2 power. Results: Most dead trees <22 cm DBH and ≥48 cm DBH died standing, while trees between 22 and 48 cm DBH uprooted or snapped. Mode of death varied among topographic positions. On plateaux, standing death predominated across all tree size classes, while on slopes standing death dominated for small trees (<14 cm DBH), while fallen deaths dominated for intermediate to large trees (14 ≤ DBH <46 cm). In valleys, fallen modes of death dominated across all size classes. Scaling and negative exponential functions with a quadratic term fitted better the size-density distribution of all trees. The scaling function fitted better the distribution of small to intermediate-sized trees while the negative exponential function and functions with a quadratic term showed the best fit to distribution of intermediate to large trees. Conclusions: Competition is the major source of mortality for small- to intermediate-sized trees, while exogenous disturbances and senescence predominate for intermediate to large trees. Modes of death, and presumed sources of mortality, change according to topographic position, but the shape of size-density distributions is not affected, demonstrating that unknown mechanisms with different processes not assumed in the metabolic theory can produce similar distributions for tropical trees. Understanding the mechanisms that determine tropical forest structure will allow us to predict forest dynamics under future climate change scenarios. © 2012 International Association for Vegetation Science.

There are several possibilities of linkage between disease, religion and healing. The article is an analysis of narratives about illness and healing through religion, based on an ethnographic approach in 10 districts of Boa Vista, Roraima, with individuals who claimed to have been healed through divine intervention. The aim is to show that disease is not limited to the universal physical symptoms of empirical reality. Magic rituals of healing are also paths open to interpretation.

The aim of this study was to evaluate the thermal comfort of the State College Santa Gemma Galgani, Curitiba, PR comparing internal and external environments in different seasons. The analysis of thermal comfort index was performed using PET. Collections were made in the fall, winter and spring of 2011 in two days and in two different environments. Every day a collect was installed equipment within the classroom and another in the outer area (outdoor), characterized as an environment 1 - outdoor area with more than 90% of waterproofing and fewer trees; and the environment 2 - external area under 30% waterproofing and more trees. The area of the college has 7634.91 m2 and 36.56% to 60.44% permeable areas and waterproof. In three seasons, the air temperature was higher in the courtyard, with the exception of autumn to the environment and a spring for the environment 2. There were significant differences in terms of comfort between locations 1 and 2, indicating that the areas are distinct permeability and the amount of vegetation. It is concluded that, overall, the classrooms of the college stations in the fall, winter and spring had thermal comfort for most of the observed period.

Discover hidden collaborations