Publications
325 results found
Das Chagas Moura M, Lins ID, Veleda D, et al., 2010, Sea level prediction by support vector machines combined with particle swarm optimization, Pages: 967-978
Sea level rise is reported by the Intergovernmental Panel on Climate Change (IPCC) as one of the main aftermaths of global warming. Besides that, the shortage of altimetry data in coastal zones renders the evaluation and comprehension of climate behavior burdensome in those areas. In this way, the forecast of sea level is of great importance and a Support Vector Machines (SVMs) prediction model is here used. SVMs are a learning method based on input/output data and do not demand previous knowledge about the process that maps input into output. Their performance is dependent on some parameters that appear in the related learning problem. A Particle Swarm Optimization (PSO) algorithm will be here adopted for selecting suitable values to these parameters. Therefore, this work applies a PSO-optimized SVM to forecast sea level measurements from the Brazilian coast. The obtained results show that PSO+SVM is a promising prediction method in the environmental field.
Chiarucci A, Araujo MB, Decocq G, et al., 2010, The concept of potential natural vegetation: an epitaph?, JOURNAL OF VEGETATION SCIENCE, Vol: 21, Pages: 1172-1178, ISSN: 1100-9233
- Author Web Link
- Cite
- Citations: 141
Meier ES, Kienast F, Pearman PB, et al., 2010, Biotic and abiotic variables show little redundancy in explaining tree species distributions, ECOGRAPHY, Vol: 33, Pages: 1038-1048, ISSN: 0906-7590
- Author Web Link
- Cite
- Citations: 178
Costa MBSF, Mallmann DLB, Pontes PM, et al., 2010, Vulnerability and impacts related to the rising sea level in the Metropolitan Center of Recife, Northeast Brazil, Pan-American Journal of Aquatic Sciences, Vol: 5, Pages: 169-177
The Metropolitan Center of Recife figures as one of the most vulnerable regions to a rise in sea level along the Brazilian coast, due to its physical characteristics and to various problems related to flooding and coastal erosion. The analysis of potential flood zones and vulnerability assessments was based on an empirical approach, considering the estimates made by the IPCC on sea level rise and extreme scenarios of astronomical ride, storm surge and run up for the region. The results indicate that for a 0.5 m (optimistic scenario) rise in sea level, at least 39.32 km2 of the area of the municipalities would become potential flood zones. In a scenario of critical sea level rise (1 m), this figure would increase to 53.69 km2. Analysis of the entire coast indicates that 81.8% of urban constructions situated less than 30 m from de shoreline and located 5 m below ground level would be severely affected by changes in sea level. Currently 45.7% of the coast is considered a high vulnerability area. In view of the severe losses predicted by the simulated scenarios, response strategies identifying the most appropriate adaptation options must be developed.
Baselga A, Araujo MB, 2010, Do community-level models describe community variation effectively?, JOURNAL OF BIOGEOGRAPHY, Vol: 37, Pages: 1842-1850, ISSN: 0305-0270
- Author Web Link
- Cite
- Citations: 47
Diniz-Filho JAF, Nabout JC, Bini LM, et al., 2010, Ensemble forecasting shifts in climatically suitable areas for <i>Tropidacris cristata</i> (Orthoptera: Acridoidea: Romaleidae), INSECT CONSERVATION AND DIVERSITY, Vol: 3, Pages: 213-221, ISSN: 1752-458X
- Author Web Link
- Cite
- Citations: 59
Nogues-Bravo D, Ohlemueller R, Batra P, et al., 2010, CLIMATE PREDICTORS OF LATE QUATERNARY EXTINCTIONS, EVOLUTION, Vol: 64, Pages: 2442-2449, ISSN: 0014-3820
- Author Web Link
- Cite
- Citations: 83
Garcia RA, Araujo MB, 2010, Planning for Conservation in a Changing Climate, NATUREZA & CONSERVACAO, Vol: 8, Pages: 78-80, ISSN: 1679-0073
- Author Web Link
- Cite
- Citations: 2
Hof C, Rahbek C, Araujo MB, 2010, Phylogenetic signals in the climatic niches of the world's amphibians, ECOGRAPHY, Vol: 33, Pages: 242-250, ISSN: 0906-7590
- Author Web Link
- Cite
- Citations: 73
Proença V, Queiroz CF, Araújo MB, et al., 2010, Biodiversidade, Ecosistemas e bem-estar humano, Editors: Pereira, Domingos, Vicente, Proença, Lisboa, Publisher: Escolar Editora, Pages: 127-179, ISBN: 9789725922743
Brook BW, Akcakaya HR, Keith DA, et al., 2009, Integrating bioclimate with population models to improve forecasts of species extinctions under climate change, BIOLOGY LETTERS, Vol: 5, Pages: 723-725, ISSN: 1744-9561
- Author Web Link
- Cite
- Citations: 116
Noriega C, Araujo M, 2009, Nitrogen and phosphorus loading in coastal watersheds in northeastern Brazil, Pages: 871-875, ISSN: 0749-0208
There is little quantification of nutrient loads in the hydrographic basins of northeastern Brazil. Activities that potentially generate nutrients and pollution along the coast are varied: waste water, including untreated sewage, agriculture (sugar cane), livestock, soil erosion and industrialization. Additionally, these areas have a high population density (167-1, 200 persons per km2) with a gradual growth rate (∼1% annually). Quantifying nutrient loads provides important information about biogeochemical processes in estuaries and the adjacent coastal zone. The objective of this work was to determine the N and P loads in 12 hydrographic basins (24, 403 km2) that flow into estuaries along the northeastern coast of Brazil were estimated using established methods. Anthropic sources were 17 to 112 times higher than natural sources for N and P, respectively. The main anthropic loads were urban use (wastewater and urban runoff) with 1.8 and 0.36 t km-2 yr -1 of N and P, respectively, agriculture (sugar cane) (0.9 t N km-2 yr-1) and industry (0.25 t P km-2 yr -1). The potential for environmental harm was determined to be medium due to N and high due to P. The highest loads of N and P came from basins with high population density.
Diniz-Filho JAF, Bini LM, Rangel TF, et al., 2009, Partitioning and mapping uncertainties in ensembles of forecasts of species turnover under climate change, ECOGRAPHY, Vol: 32, Pages: 897-906, ISSN: 0906-7590
- Author Web Link
- Cite
- Citations: 410
Filipe AF, Araujo MB, Doadrio I, et al., 2009, Biogeography of Iberian freshwater fishes revisited: the roles of historical versus contemporary constraints, JOURNAL OF BIOGEOGRAPHY, Vol: 36, Pages: 2096-2110, ISSN: 0305-0270
- Author Web Link
- Cite
- Citations: 70
Silva M, Araujo M, Servain J, et al., 2009, High-resolution regional ocean dynamics simulation in the southwestern tropical Atlantic, Ocean Modelling, Vol: 30, Pages: 256-269, ISSN: 1463-5003
The southwestern tropical Atlantic (05°S-25°S/20°W-47°W), where part of the South Equatorial Current (SEC) enters at its eastern border, is of particular interest as it is fed by many western boundary currents along the eastern Brazilian continental shelf. However, the long-term variability of the dynamics in this region, which are also important as they contribute to the climate over northeastern Brazil, is largely unknown. We use the Regional Ocean Model System (ROMS) here for the first time in this area to simulate the ocean circulation with an isotropic horizontal grid resolution of 1/12° and 40 terrain-following layers. As a primary evaluation of the ROMS configuration, we explore surface and vertical thermal structures, the surface mixed layer, and mass transports within the upper levels. Interannual variability results are compared with the first two-year series of observed thermal profiles derived from the three PIRATA-SWE moorings. The simulated thermal structure in the upper ocean layers agrees well with in-situ data. ROMS simulations point out a broad and relatively weak SEC flow composed of a sequence of more or less defined near-surface cores. The westward SEC transport for the upper 400 m along the PIRATA-SWE section, calculated from the ROMS simulation for 2005-2007, shows an average volume transport of 14.9 Sv, with a maximum observed in JFM (15.7 Sv), and a minimum during MJJ (13.8 Sv). ROMS results indicate that the 2005-2007 seasonal near-surface westward SEC transport is modulated by the zonal wind variability. Three zonal sections extending from the American continent to the PIRATA buoy sites confirm that stronger northward NBUC transport and decreasing BC transport were achieved during May 2006 and May 2007, i.e. at the time the sSEC bifurcation reaches its southernmost position. On the other hand, the maximum southward BC flow was verified during January 2006, January 2007 and March 2007, with a minimum northward NBUC flow
Araújo MB, 2009, Climate change and Spatial Conservation Planning, Spatial conservation prioritization, Editors: Moilanen, Wilson, Possingham, Publisher: Oxford University Press, USA, Pages: 172-184, ISBN: 9780199547760
The book includes chapters on the most widely used and latest software, and concludes with an insight into the future of the field.
Thuiller W, Lafourcade B, Engler R, et al., 2009, BIOMOD - a platform for ensemble forecasting of species distributions, ECOGRAPHY, Vol: 32, Pages: 369-373, ISSN: 0906-7590
- Author Web Link
- Cite
- Citations: 1541
Silva AC, Bourles B, Araujo M, 2009, Circulation of the thermocline salinity maximum waters off the Northern Brazil as inferred from in situ measurements and numerical results, Annales Geophysicae, Vol: 27, Pages: 1861-1873, ISSN: 0992-7689
High resolution hydrographic observations of temperature and salinity are used to analyse the subsurface circulation along the eoast of North Brazil, off the Amazon mouth, between 20° S and 60° N. Observations are presented from four cruises carried out in different periods of the year (March-May 1995, May-June 1999, July-August 2001 and October-November 1997). Numerical model outputs complement the results of the shipboard measurements, and are used to complete the descriptions of mesoscale circulation. The Salinity Maximum Waters are here analyzed, principally in order to describe the penetration of waters originating in the Southern Hemisphere toward the Northern Hemisphere through the North Brazil Current (NBC)/North Brazil Undercurrent (NBUC). Our results show that, if the Equatorial Undercurrent (EUC) is fed by Northern Atlantic Waters, this contribution may only occur in the ocean interior, east of the western boundary around 100 m depth. Modeling results indicate a southward penetration of the Western Boundary Undercurrent (WBUC) below the thermocline, along the North Brazilian coast into the EUC or the North Equatorial Undercurrent (NEUC) (around 480° W-30° N). The WBUC in the region does not flow more south than 3° N. The northern waters are diverted eastward either by the NBC retroflection or by the northern edge of the associated clockwise rings. The existence of subsurface mesoscale rings associated to the NBC retroflection is evidenced, without any signature in the surface layer, so confirming earlier numerical model outputs. These subsurface anticyclones, linked to the NBC/NBUC retroflection into the North Equatorial Undercurrent and the EUC, contribute to the transport of South Atlantic high salinity water into the Northern Hemisphere. © Author(s) 2009.
Hickler T, Fronzek S, Araujo MB, et al., 2009, An ecosystem model-based estimate of changes in water availability differs from water proxies that are commonly used in species distribution models, GLOBAL ECOLOGY AND BIOGEOGRAPHY, Vol: 18, Pages: 304-313, ISSN: 1466-822X
- Author Web Link
- Cite
- Citations: 46
Anderson BJ, Akcakaya HR, Araujo MB, et al., 2009, Dynamics of range margins for metapopulations under climate change, PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, Vol: 276, Pages: 1415-1420, ISSN: 0962-8452
- Author Web Link
- Cite
- Citations: 253
Araujo MB, Thuiller W, Yoccoz NG, 2009, Reopening the climate envelope reveals macroscale associations with climate in European birds, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 106, Pages: E45-E46, ISSN: 0027-8424
- Author Web Link
- Cite
- Citations: 66
Bini LM, Diniz-Filho JAF, Rangel TFLVB, et al., 2009, Coefficient shifts in geographical ecology: an empirical evaluation of spatial and non-spatial regression, ECOGRAPHY, Vol: 32, Pages: 193-204, ISSN: 0906-7590
- Author Web Link
- Cite
- Citations: 220
Baselga A, Araujo MB, 2009, Individualistic vs community modelling of species distributions under climate change, ECOGRAPHY, Vol: 32, Pages: 55-65, ISSN: 0906-7590
- Author Web Link
- Cite
- Citations: 89
da Silva AC, Santos MDLS, Araujo MC, et al., 2009, Hydrological observations and modeling results of the seasonal and spatial spread of the Amazonian water plume, Acta Amazonica, Vol: 39, Pages: 361-370, ISSN: 0044-5967
In this study, we present surface synoptic data collected during four oceanographic cruises undertaken in March-April 1995, October-November 1997, April-May 1999 and August-September 2001 in the Brazilian Program "REVIZEE/SCORE-NO" and a combination of model results (1/6 deg.). The emphasis of this paper is to point out the monthly changes on the spreading of the Amazon plume over the external Amazon shelf area and the eastern region of the Amazon River. Hydrographic data and model results demonstrated that during March-May, the Amazon plume moved southwestward along the northern coast of Brazil, decreasing during August-September; but this was not observed during October-November. Model results revealed ring signatures shedding from the North Brazil Current (NBC). Results also showed that during August the Amazon plume encircling the NBC retroflection was around 7° N.
Noriega CE, Muniz K, Flores-Montes MJ, et al., 2009, Hydrobiological time series in a tropical estuary (Brazil), Revista de Biologia Marina y Oceanografia, Vol: 44, Pages: 93-108, ISSN: 0717-3326
This paper presents a hydrobiological time series at Barra de Jangadas estuary in Northeastern Brazil. Studies were carried out during seven consecutive days from a spring to a neap tide, in one fixed station during the dry (January) and rainy (July) seasons, in 2001. The meteorology (rainfall, evaporation, wind intensity), hydrology (temperature, salinity, pH, dissolved oxygen-DO and relative saturation, BOD5, nutrients (NH3+ NH4, NO-2, NO-3, PO-34, SiO2)), bathymetry, current intensity and, chlorophyll-a, were studied. The principal component analysis (PCA) explained 80% of the total variance showing an inverse relationship between nutrients and DO, salinity and pH. This analysis showed a positive correlation between low tide and nutrients, indicating anthropogenic pollution. The water temperature presented low seasonal variation, similar to chlorophyll-a, which presented values over 20 mg m-3, characterizing a eutrophic environment. Higher salt concentrations were registered during the dry season with no vertical stratification. DO varied significantly in both seasons. Total dissolved inorganic nitrogen and dissolved inorganic Phosphorus values in July were in general 2 to 5 times higher than values registered in January, respectively. The average N/ P ratio varied from 35:1 in January to 8:1 in July, being both phosphate and nitrogen limiting for phytoplankton growth. Night/day differences showed that in January, ammonia decreased in higher proportion than the other nitrogen compounds indicating assimilation by the autotrophic organisms during the day.
Cabeza C, Varela J, Bove I, et al., 2009, Two-layer stratified flows over pronounced obstacles at low-to-intermediate Froude numbers, Physics of Fluids, Vol: 21, ISSN: 1070-6631
Two-layer stratified flows over abrupt topographic obstacles, simulating relevant situations in oceanographic problems, are investigated numerically and experimentally in a simplified two-dimensional situation. Experimental results and numerical simulations are presented at low-to-intermediate Froude numbers for two different obstacles: one semicylindrical and the other prismatic. In both cases, four different flow regimes downstream of the obstacles are found: (I) subcritical flow, (II) internal hydraulic jump, (III) Kelvin-Helmholtz instability at the interface, and (IV) shedding of billows. The critical values of the Froude number for the transition between different regimes depend strongly on the shape of the obstacle. In regime (III), we show that the characteristics of the lee wave that appears past the obstacle can be explained with a theoretical stability analysis. Almost independence of the vortex shedding frequency with upstream velocity is observed and explained.
Hortal J, Araujo MB, Lobo JM, 2009, Testing the effectiveness of discrete and continuous environmental diversity as a surrogate for species diversity, ECOLOGICAL INDICATORS, Vol: 9, Pages: 138-149, ISSN: 1470-160X
- Author Web Link
- Cite
- Citations: 24
Santos MLS, Muniz K, Barros-Neto B, et al., 2008, Nutrient and phytoplankton biomass in the Amazon River shelf waters., An Acad Bras Cienc, Vol: 80, Pages: 703-717
The Amazon River estuary is notable at the Amazon Continental Shelf, where the presence of the large amount of water originating from the Amazon during the river's falling discharge period was made evident by the low salinity values and high nutrient levels. Even so, the presence of oceanic waters in the shelf area was significant. Dissolved organic nitrogen was the predominant species of the nitrogen cycle phases, followed by total particulate nitrogen, nitrate, ammonium and nitrite. The chlorophyll a data in the eutrophic area indicated that there is sufficient nitrogen in the area to withstand productivity, though dissolved inorganic nitrogen removal processes are faster than regeneration or mineralization. The anomalous amounts of inorganic dissolved nitrogen showed more removal than addition. The simulations with the bidimensional MAAC-2D model confirmed that high nutrient waters are displaced northwest-ward (two cores at 2.5 degrees N-50 degrees W and 4 degrees N-51 degrees W) by the stronger NBC during falling river discharge. During high river flow period these nutrient-rich lenses are distributed around 0.5 degrees N-48.5 degrees W as well as along the shallow Amazonian shelf (20 m-50 m depth, 1 degree N-3.5 degrees N), as a result of the spreading of Amazon freshwater outflow.
Keith DA, Akcakaya HR, Thuiller W, et al., 2008, Predicting extinction risks under climate change:: coupling stochastic population models with dynamic bioclimatic habitat models, BIOLOGY LETTERS, Vol: 4, Pages: 560-563, ISSN: 1744-9561
- Author Web Link
- Cite
- Citations: 463
Ohlemueller R, Anderson BJ, Araujo MB, et al., 2008, The coincidence of climatic and species rarity:: high risk to small-range species from climate change, BIOLOGY LETTERS, Vol: 4, Pages: 568-572, ISSN: 1744-9561
- Author Web Link
- Cite
- Citations: 263
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.