999 resultados para Ecologia de Ecossistemas


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Doze imagens Landsat 8 foram usadas em conjunto com uma rede de onze de estações agrometeorológicas para a modelagem em larga escala de indicadores do balanço hídrico nos agrosecossistemas da bacia hidrográfica do Submédio São Francisco, compostos por vegetação natural e culturas irrigadas. O algoritmo SAFER foi usado para a obtenção da evapotranspiração (ET), a qual foi usada em conjunto com dados de precipitação (P) interpolados. Para a classificação da vegetação e caracterização dos indicadores, o algoritmo SUREAL foi aplicado na determinação da resistência da superfície (rs) sendo valores limites de rs usados na separação em culturas agrícolas e espécies da Caatinga. Nas condições naturais mais úmidas do início do ano, as taxas de evapotranspiração na vegetação natural foram em torno de 30% daquelas para culturas irrigadas, enquanto que nas mais secas estas ficaram em torno de 6%. Considerando-se todo o ano, as culturas irrigadas consumiram cinco vezes mais água que as espécies da Caatinga, uma quantidade extra de 870 mm ano-1. Maiores cautelas com relação ao manejo de irrigação devem ser tomadas no período climaticamente mais seco do ano, devido ao aumento da retirada da água do Rio São Francisco, criando maiores possibilidades de conflitos entre os setores agrícolas e outros usuários da água.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Ecological studies were conducted in the ichthyofauna of Cedro, a small headwater stream located in a degraded area of State of São Paulo, Brazil, situated in the upper Paraná River basin. These are the results of two non-consecutive years observations and collections in two biotopes of that stream: a pool and a rapid. The ecological characteristics studied change in space and time. The present richness of species is high (21 species), nine of which are constant, six accessory and six accidental. The diversity is low (0.69 to 2.38), and the numeric predominance, from one to three species, occurred in both biotopes. The most frequent species are Poecilia reticulata (Peters, 1859) (28.1%), Corydoras cf. aeneus (Gill, 1858) (20.3%) and Hypostomus cf. ancistroides (Ihering, 1911) (19.8%). The density ranges from 0.7 to 19.8 specimens/m³. The similarity index indicates high similarity between the ichthyofauna (45.0% to 95.0%) inside the same or contiguous biotopes. The evenness (0.46 to 1.0) is comparable to those found in similar studies carried out in other streams.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This work presents the results of a survey in oil-producing region of the Macau City, northern coast of Rio Grande do Norte. All work was performed under the Project for Monitoring Environmental Change and the Influence of Hydrodynamic forcing on Morphology Beach Grass Fields, Serra Potiguar in Macau, with the support of the Laboratory of Geoprocessing, linked to PRH22 - Training Program in Geology Geophysics and Information Technology Oil and Gas - Department of Geology/CCET/UFRN and the Post-Graduation in Science and Engineering Oil/PPGCEP/UFRN. Within the economic-ecological context, this paper assesses the importance of mangrove ecosystem in the region of Macau and its surroundings as well as in the following investigative exploration of potential areas for projects involving reforestation and / or Environmental Restoration. At first it was confirmed the ecological potential of mangrove forests, with primary functions: (i) protection and stabilization of the shoreline, (ii) nursery of marine life, and (iii) source of organic matter to aquatic ecosystems, (iv) refuge of species, among others. In the second phase, using Landsat imagery and techniques of Digital Image Processing (DIP), I came across about 18,000 acres of land that can be worked on environmental projects, being inserted in the rules signed the Kyoto Protocol to the market carbon. The results also revealed a total area of 14,723.75 hectares of activity of shrimp production and salting that can be harnessed for the social, economic and environmental potential of the region, considering that over 60% of this area, ie, 8,800 acres, may be used in the planting of the genus Avicennia considered by the literature that the species best sequesters atmospheric carbon, reaching a mean value of 59.79 tons / ha of mangrove

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Sea urchins are common benthic organisms on coastal ecosystems of tropical and temperate shallow waters. The impact of sea urchins populations in shore communities is density-dependent, and therefore, knowledge of the life history of these animals is important to understand these interactions. Between 2000 and 2005 a population boom of Tripneustes ventricosus was observed in the Fernando de Noronha Archipelago. In 2004 a research program was started to monitor the population dynamics of T. ventricosus in the archipelago, when it noted a lack of basic information on the biology and reproduction of this species, despite its broad geographic distribution and economic importance in parts of its occurrence. In this context, this work focuses on the reproductive biology of T. ventricosus with emphasis on the description of the gametogenic stages. Between December 2006 and July 2007, ten urchins were collected by snorkeling in two sites of the archipelago, totaling 120 individuals. Gametogenic stages were described for both sexes through microscopic analysis, and were defined as: Recovery, Growing, Premature, Mature and Spawning. Results showed increasing in Gonad index throughout of months of sampling and suggest that the reproductive cycle of the species in the archipelago is annual

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The feeding habits and biological aspects of the reproductive cycle of two-spot astyanax, Astyanax cf. lacustris (Reinhardt, 1874) were investigated. Fish samples were captured on a monthly basis, using gillnets of 4 cm mesh size, from the Piató Lake, Assu, Rio Grande do Norte, during the period of September, 2006 to August, 2007. Physico-chemical parameters, such as, temperature, electrical conductivity and dissolved oxygen of the lake were registered. The monthly values of rainfall also were obtained. The 360 individuals captured, were measured, weighed, dissected, and stomach weight and the stage of gonadal maturity were registered. The stomach contents analyses were carried out based on volumetric method, points, frequency of occurrence and applying the Index of Relative Importance. The degrees of repletion of the stomachs were determined besides the Index of Repletion relating to feeding activity variations and frequency of ingestion with limnological parameters and rainfall. The food items identified were separated into distinct groups according to their origin. Sex ratio and Gonadosomatic Relation of females were verified to determine the spawning period and fecundity. The physico-chemical parameters presented the following annual mean values: temperature = 28.8ºC, electrical conductivity = 992.5 µS.cm-1; dissolved oxygen = 4.9 mg.L-1 during the study period. The annual mean of the rainfall was 63.5 mm. The results indicate that this species present an omnivorous feeding habit with a tendency towards insectivory, with an increase in feeding activity during the dry season. The aquatic oxygen to interfere very importance in the feeding activity than the others factors physico-chemicals of water and rainfall. There was a predominance of females, with a sex proportion of 1M:7F. The macroscopic characteristics of the ovaries and testicles revealed four stages of gonadal development: immature, maturing, mature and spent. A temporal variation was observed for the gonadal development of males and females. There was reproductive activity through out the year, with peaks in the months of February, April and June to correspond with the rain of precipitation of the region. The mean fecundity was 7.681 mature oocytes, varying from 4.476 to 12.036, with mean of 7.681. There was positive relation between fecundity and body mass. Condition Factor is not an efficient indicator of the reproductive period of this species. The species A. cf. lacustris is an opportunist and is well adapted to the conditions of the semi-arid Caatinga Biome

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Caatinga biome is rich in endemic fish species fauna. The present study the results of fish faunal surveys conducted in the hydrographic basin of Piranhas-Assu of the Brazilian Caatinga biome. The fish samples collected were distributed in four orders (Characiformes, Perciformes, Siluriformes and Synbranchiformes), 11 families (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae) and 22 species, of which 17 are endemic and five have been introduced from other basins. The order Characiformes was the most representative in number of species (46,35% ) followed by Perciformes (35,38%), Siluriformes (17,44%) and Synbranchiformes (0,5%). The Nile tilapia, Oreochomis niloticus, the only exotic species, was most expressive in number of individuals (24.92%) followed by the native species piau preto, Leporinus piau (18,77 %). Considering the relative frequency of occurrence of the 22 species, 13 were constant, five were accessory and four were occasional. This study investigated the reproductive ecology of an endemic fish black piau, Leporinus piau from the Marechal Dutra reservoir, Acari, Rio Grande do Norte. Samplings were done on a monthly basis from January to December 2009, and a total of 211 specimens were captured. The environmental parameters such as rainfall, temperature, pH, electrical conductivity and dissolved oxygen of water were recorded. The sampled population showed a slight predominance of males (55%), however females were larger and heavier. Both sexes of L. piau showed positive allometric growth, indicating a higher increase of weight than length. The first sexual maturation of males occurred at smaller size, with 16.5 cm in total length than females (20.5 cm). During the reproductive period, the condition factor and gonadosomatic index (GSI) of L. piau were negatively correlated. This species has large oocytes with a high mean fecundity of 54.966 with synchronous oocyte development and total spawning

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The reproductive ecology of fish plays a key role both for rational exploitation methods and for protective measures of natural stocks. The purpose of this study was to analyze the reproductive aspects of the damsel-fish, Stegastes fuscus, during October 2004 to September 2005, in the coastal rocky reefs of Búzios Beach, Nísia Floresta, RN. Fish were captured using hooks and hand nets, during low tide. Reproduction was determined using sexual ratio, mean length of first maturation (L50), absolute fecundity and macroscopic characteristics of gonads. The following parameters were related to gonadosomatic index (GSI): condition factor (CF), hepatosomatic index (HSI), rain fall and temperature. In relation to sex distribution, it was observed that 78% were females and 22% were males. The L50 was 6.2 cm for females and 7.0 for males. Average fecundity was 6832 oocytes. Results showed that S. fuscus had better body condition in the months prior to spawning, particularly during initial and intermediate stages of maturation. Five stages of gonadal maturation were identified through macroscopic analysis: immature, in maturation, mature, spent and resting. The HSI was inversely related to the GSI. This was possibly due to the reproductive cycle of this species which was associated to the dry period of this region. During this period, low rain fall and high temperatures provide an propitious reproductive condition for the study species

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Oligoplites palometa (Cuvier) and Oligoplites saurus (Bloch & Schneider) (Osteichthyes: Carangidae) are coastal pelagic fish species. The objective of this study was to investigate the effect of parasitism by isopods and the reproductive biology of the leather jack, Oligoplites spp. A total of 113 individuals of Oligoplites spp (35 of O. saurus and 78 of O. palometa) were captured during the period between January, 2005 and July, 2007 from the coastal waters of Natal, RN. The morphometric and meristic characters were registered; macroscopic analyses were done to collect the isopod parasites and the gonads were observed to verify the reproductive aspects. The crustacean isopod parasite, Cymothoa spinipalpa (Isopoda: Cymothidae) was encountered on the tongue in the oral cavity in both fish hosts. The parasitic indices of C. spinipalpa showed high values of prevalance of 51,4% for O. saurus and 64,1% for O. palometa. The host presented significant correlations between body mass and body length of O. palometa and the number of parasites. Body lengths of female C. spinipalpa were small due to the limited space available in the oral cavity of the host. There was a significant difference in the sex ratio of O. palometa, males outnumbered the females. The isopod parasites showed specificity to the oral cavity of hosts. Macroscopic analyses of gonads showed four stages of gonadal development for both sex of O. palometa: immature, maturing, mature and spent

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The diet study of birds has contributed historically as a model for use to understanding ecological patterns and strategies used by several other groups of vertebrates, which are observed in season patterns and temporal availability of resources, and other. This study has as objective generate information concerning the diet of insectivorous birds during rainy season and dry season, as well as analyze Index food importance, niche overlap, niche breadth, electivity, and seasonal availability of prey. The study was conducted in a fragment of about 270 ha (center coordinates and 5 º 53'S 35 ° 23'W). The sampling of birds occurred between March 2008 and December 2009 in three pre-established trails. Catches of birds were performed using 10 mist nets placed in line, where each trails was sampled once a month. Samples of pellets were obtained by means of tartar emetic. Sampling of availability of prey occurred between February 2009 to December 2009. We used two methods of sampling (pitfall traps and Shake cloths). We captured 269 individuals of 21 species of insectivorous birds. We collected 4116 invertebrates of which 3259 in the rainy season and 857 in the dry season. We obtained 174 samples stomach, where 10 species were exclusively insectivorous diet, nine fed on insect/plant material, an insect/plant material/vertebrate and one for insect/vertebrate. During the rainy season was observing difference between the consumption of items with higher food importance. The Coleoptera was item with higher food importance (73%), followed by Formicidae (7%) and Araneae (6%). During the dry season, no difference was found difference between the consumption of items with higher food importance. The Coleoptera was item with higher food importance (34%), followed by seeds (29%) and Formicidae (18%). The highest levels of niche overlap occurred during the rainy season, while the dry season was characterized by high levels of niche 11 segregation. This indicates that the local insectivorous birds community was structured differently between periods. No was found correlation between the values of niche breadth to the mean weight of the body size. We observed seasonal patterns in prey availability, with the peak availability of invertebrates observed seasonal patterns in rainy season. The insectivorous birds selected the same species richness during both periods, showing a specialized diet. Thamnophilus pelzelni was the only species that had their diet influenced by seasonality. Regarding the overall diet of insectivorous birds, observed a high consumption of prey, whose food availability caused the birds could invest and increase their food resources

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Quando pela primeira vez, por volta de 2010/2011 se colocou a questão da definição das áreas onde os ecossistemas estariam dependentes de águas subterrâneas, e entendendo-se por “ecossistemas dependentes de águas subterrâneas” os ecossistemas que dependem, em todo ou em parte de águas subterrâneas e que seriam irrevogavelmente afetados em caso de afetação da quantidade ou qualidade das águas subterrâneas, tornou-se necessário criar mecanismos para rapidamente se conseguirem identificar esses sistemas ecológicos. Para esse fim, foram em primeiro lugar, com base em dados de níveis freáticos de águas subterrâneas, identificadas as áreas onde as águas subterrâneas se situariam próximo da superfície do solo. Depois foram usados modelos conceptuais, onde estes existiam, para determinar as zonas onde havia hipóteses de haver ascensão de água subterrânea. Finalmente, foram identificadas áreas onde condições hidrogeológicas locais permitiriam a sustentação de ecossistemas com caraterísticas específicas (lagoas temporárias, por exemplo). As áreas identificadas foram então comparadas com as zonas protegidas classificadas em Portugal (Rede Natura 2000, Parques e Reservas Nacionais, etc.). Curiosamente, verificou-se de imediato uma grande coincidência entre as áreas identificadas no estudo e as áreas protegidas já definidas, mostrando que as áreas ecologicamente importantes já o eram por razões também ligadas às águas subterrâneas. Depois avançou-se para uma análise mais ecológica, com base em dados pré-existentes, e recorrendo a uma equipa pluridisciplinar. Por esta via foram identificados sistemas em linhas de água ou ligados a lagos e sistemas terrestres, de que resultou toda a cartografia final dos ecossistemas dependentes de águas subterrâneas dos planos de bacia no sul de Portugal.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

As espécies invasoras são uma das principais ameaças à biodiversidade causando impactes ecológicos, económicos e nos serviços dos ecossistemas. O conhecimento conjunto da dinâmica das séries de vegetação e da ecologia das plantas invasoras é uma ferramenta útil na recuperação ecológica de áreas invadidas e na prevenção de invasões. Este trabalho tem como objectivo principal averiguar a relação entre a distribuição das plantas invasoras e as comunidades vegetais terrestres do Sul de Portugal. Para tal, fez-se corresponder a distribuição de nove plantas invasoras selecionadas com as séries de vegetação e territórios biogeográficos, em 60 quadrículas com 1 Km2. A Província Lusitana-Andaluza Costeira revelou-se a mais invadida, com predomínio de Acacia dealbata, Acacia longifolia e Opuntia maxima no potencial climatófilo de sobreiral psamófilo; A. longifolia dominou no potencial edafoxerófilo de zimbral de Juniperus turbinata e A. dealbata e Arundo donax no potencial edafo-higrófilo de freixial. Com base nos resultados, estabeleceram-se áreas prioritárias para intervenção; INVASIVE PLANTS IN SOUTHERN PORTUGAL A BIOGEOGRAPHICAL APPROACH Abstract: Invasive species are one of the main threats to biodiversity worldwide and are responsible for negative impacts at ecological, economic and ecosystem services level. Complementarity between vegetation series dynamics and invasive plants ecology knowledge is essential to address ecological restoration and to prevent invasions. The main goal of this work is to investigate the relationship between invasive plants distribution and terrestrial plant communities of Southern Portugal. Fieldwork was conducted in 60 1 Km2 sampling plots and a correspondence was made between nine selected invasive plants and the vegetation series and the biogegraphic units The Andalusian-Lusitanian Coastal province was the most invaded biogeographic unit and revealed the dominance of Acacia dealbata, Acacia longifolia and Opuntia maxima in the cork oak psammophilous series; A. longifolia dominated in the maritime turbinate juniper edapho-xerophilous series and A. dealbata and Arundo donax in the ash edaphohygrophilous groves potential. Based on the results, priority areas for intervention were defined.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Este projeto tem como objetivo estabelecer colônias de insetos Conotrachelus sp. para estudos de ecologia química das brocas do cupuaçu.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

O estudo evidencia o ecoturismo, relacionando-o  com  ecologia e com a dinâmica e evolução da sociedade moderna que exige espaços de consumo para lazer.  Analisa a interface do turismo com o meio ambiente, explica impactos socioambientais associados à mercantilização da natureza e identifica soluções. Associa o ecoturismo aos compromissos de mudanças da sociedade de consumo, difundindo princípios de sustentabilidade.  Apresenta perfil de ecoturistas e diferenciações entre geossistema e ecossistema. Nos geossistemas  Pantanal, Amazônia, Litoral, Serras, Caatingas e Cerrados estão ecossistemas propícios a interpretação ambiental ou a descoberta da natureza com atribuição de significados. Além de técnicas para  realização adequada do lazer em Unidades de Conservação Ambiental, histórias de trilhas e formas diferenciadas de realizá-las. Aponta utilização de forma sustentável do patrimônio natural e cultural, proteção ambiental, consciência ecológica e oportunidades às comunidades, com resultados econômicos favoráveis à melhoria das condições de vida dos pólos de ecoturismo. Explica a produz de baixos impactos ambientais, sustentação socioeconômica para unidades de conservação ambiental e alternativas para economias locais, com agricultura familiar, extrativismo, pesca artesanal, atividades ligadas à natureza. Toma como base áreas de ecoturismo no Ceará - Brasil que respeitam exigências éticas para a sustentabilidade do ecoturismo, e em especial da sociedade.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Estudaram-se alguns aspectos da ecologia da polinização da bacabi (Oenocarpus mapora Karsten). As observações foram feitas em seis indivíduos com 11 anos de idade, em uma área experimental da Embrapa Amazônia Oriental, Belém (PA), de julho/1990 a junho/1991. A inflorescência apresentou flores unissexuais, sendo envolvida por duas brácteas. Detectou-se que as flores femininas são actinomorfas, tendo três sépalas e três pétalas claras aderidas ao estigma, estando ladeadas por duas masculinas, as quais têm a mesma cor e quantidade de sépalas e pétalas com seis estames. Os eventos de floração e frutificação ocorreram em todos os meses de observação, com picos de floração em janeiro e de frutificação em setembro. Na inflorescência, os eventos florais ocorreram em fases distintas em 26 dias. A fase masculina iniciou com a exposição da inflorescência, sendo desuniforme, completando-se em sete dias, tendo cada for antese explosiva e caindo em minutos. A fase feminina, também, foi desuniforme e ocorreu em 12 dias, começando por volta de sete dias após o termino da masculina, ficando as flores viáveis por 24 a 36 horas, após o estigma se expor. Ambas tiveram anteses vespertinas a partir das 16 horas. A viabilidade polínica foi alta, tanto em flores solitárias como nas díades. As recompensas florais foram odor, pólen e secreção estigmática. Foram gastos 110 dias para a maturação dos frutos. Os insetos visitantes foram os coleópteros, hymenópteros e heterópteros. Pode-se, então, considerar a bacabi como espécie monoica, protândrica com síndrome de entomofilia.