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1.
I review the distribution of genus Alouattain the Marajó Archipelago based on geographic variation of pelage color patterns. Specific differences exist among the labeled specimens at Museu Paraense Emílio Goeldi, which are confirmed via new field information from wild populations. The animals from Marajó, Caviana, and Mexiana Islands possess color patterns of Alouatta belzebul,while Alouatta seniculusis confirmed as the species that inhabits Gurupá Island. The high variability of pelage coloration of the animals from Marajó, Caviana, and Mexiana Islands includes all phenotypes formerly designated as different subspecies. The howler populations from these three islands belong to the same subspecies as those populations that inhabit the region of Tucurui dam reservoir (area 4). Finally, it seems that, as also suggested by chromosome studies, A. belzebulprobably comprises different epiphenotypes without taxonomic validity.  相似文献   

2.
The aim of this study was to describe spatial patterns of the distribution of leprosy and to investigate spatial clustering of incidence rates in the state of Ceará, Northeast Brazil. The average incidence rate of leprosy for the period of 1991 to 1999 was calculated for each municipality of Ceará. Maps were used to describe the spatial distribution of the disease, and spatial statistics were applied to explore large- and small-scale variations of incidence rates. Three regions were identified in which the incidence of leprosy was particularly high. A spatial gradient in the incidence rates was identified, with a tendency of high rates to be concentrated on the North-South axis in the middle region of the state. Moran's I statistic indicated that a significant spatial autocorrelation also existed. The spatial distribution of leprosy in Ceará is heterogeneous. The reasons for spatial clustering of disease rates are not known, but might be related to an heterogeneous distribution of other factors such as crowding, social inequality, and environmental characteristics which by themselves determine the transmission of Mycobacterium leprae.  相似文献   

3.
Velho  L. F. M.  Lansac-Tôha  F. A.  Bonecker  C. C.  Bini  L. M.  Rossa  D. C. 《Hydrobiologia》2001,(1):385-391
The assessment of factors that determine the spatial distribution of zooplankton abundance is a central issue in zooplankton ecology. Since these factors are, in the most cases, spatially autocorrelated, especially in reservoirs, it is frequently difficult to isolate the primary causes that explain the variation in zooplankton abundance. In this paper, the spatial variation of copepods in Corumbá Reservoir (Goiás, Brazil) was studied. Sets of variables were used to model copepod abundance variation: limnology (abiotic variables), phytoplankton and spatial position of sampling sites. The copepod assemblage was composed of Thermocyclops minutus, Thermocyclops decipiens, Mesocyclops longisetus and Notodiaptomus iheringi. Along the reservoir's main axis, abundance increases, albeit not linearly, towards the lacustrine zone. High abundance, similar to that found in the lacustrine region, was also observed in the lateral arms. These patterns were very similar for different years and seasons. Copepods were significantly correlated with phytoplankton and geography. After controlling for the effect of space, the relationship between copepods and phytoplankton was not significant (partial Mantel test). This result indicates that hydrology is the primary process that controls not only the abundance of copepods, but also limnological features and food resources, which are commonly used to explain variations in zooplankton abundance.  相似文献   

4.
Electrophoresis of rotavirus RNA in polyacrylamide gel was carried out by using faecal samples collected from children living in the peripheral area of Belém, Brazil. Typical rotavirus profiles (eleven bands) were noted in 46(76.7%) out of 60 ELISA rotavirus positive specimens. According to the electrophoretic patterns, 5(10.9%) were classified as subgroup I, while 41(89.1%) of them as subgroup II. Lacking of bands 10 and 11 in 14(23.3%) samples did not allow us to classify their electropherotypes. The profile coded as "1N2L" was the predominant one, accounting for 65.2% of the classified strains.  相似文献   

5.
Litterfall consumption and predation on propagules is high in Indo-west-Pacific mangroves and low in Atlantic-east-Pacific ones. However, data for the latter area comes only from Caribbean and subtropical North American mangroves. South American data on litterfall consumption contradicts this view but data on predation on propagules are scarce. We measured predation on Rhizophora mangle, Avicennia schaueriana and Laguncularia racemosa propagules and seedlings and related to densities of large (>1.5 m high) and small (1–1.5 m) plants in mature and regenerating mangroves in Ceará state, Brazil. Predation on propagules was the highest among American mangroves (R. mange, >47%; A. schaueriana, >97%; L. racemosa, >83%), especially in the regenerating area. Predation on seedlings was low (maximum of 14% for R. mangle) and did not hamper growth. The dominance of large R. mangle trees in the mature mangrove is consistent with the lower predation on its propagules but the high proportions of small plants of other species indicate that dominance is achieved by mechanisms other than predation. In the regenerating mangrove, dominance of large and small L. racemosa and A. schaueriana plants is not consistent with the high predation on their propagules. Therefore, predation is not the main determinant of the species composition in this mangrove system.  相似文献   

6.
The abundance of microcrustacean species recorded in plankton samples from the littoral and pelagic zones of the Upper Paran River, State of Mato Grosso do Sul, Brazil, was evaluated in relation to abiotic and biotic environmental factors. The cladocerans Bosminopsis deitersi and Bosmina hagmann i were most abundant. The presence or absence of aquatic macrophytes also influenced abundance and species composition. The true zooplankton species were most abundant at the pelagic stations, while species of Chydoridae and Macrothricidae contributed markedly to microcrustacean abundance and species richness at littoral stations. Species abundance was also strongly affected by water level variation. Microcrustaceans, mainly bosminids, were most abundant during low water. During high water, bosminids decreased in abundance while most other species increased. The higher variation of the environmental factors during high water probably explains the shift in abundance patterns. Changes in water level increased mixing of littoral and pelagic microcrustaceans between sampling stations.  相似文献   

7.
In this paper, we present a bioclimatic approach to (1) differentiate populations of the endemic Mexican columnar cactus Neobuxbaumia tetetzo within the Tehuacán-Cuicatlán Valley and (2) evaluate, under two possible future scenarios (years 2050 and 2080), the effects of climate change on the total species distribution in this area, as well as on groups of populations defined by their bioclimatic models. Four population groups were identified, and principal component analysis showed that the variables that explained more than 40% of the climatic variation were precipitation of the wettest quarter and temperature seasonality. Bioclimatic models under the different scenarios indicated that when the overall species distribution was analyzed, this area will probably have contracted by 19.5% by the year 2050 and 47.05% by the year 2080, whereas the separate analysis of population groups projected area contractions of 18.4% by the year 2050 and 51.95% by the year 2080. These results demonstrate the importance of exploring new approaches for evaluating and predicting current and future distribution of plant species.  相似文献   

8.
To determine the polymorphisms of the prion protein gene in sheep from the state of Paraná, Brazil, 323 animals of meat breeds (Suffolk, Hampshire Down, Texel, Ile de France, Dorper, Dorset, Santa Inês and crossbreds) were genotyped by restriction fragment length polymorphism (RFLP) analysis. The most frequent allele was ARQ, with a frequency of 0.61, followed by ARR (0.30). VRQ and AHQ alleles were present at very low frequencies (0.13 and 0.05 respectively), and the ARH allele was not found. Seven genotypes were identified (ARR/ARR, ARR/ARQ, ARQ/ARQ, ARR/VRQ, ARR/AHQ, ARQ/VRQ and ARQ/AHQ), of which ARQ/ARQ was the most frequent (0.41). The Santa Inês breed and crossbred animals showed the highest genotypic variability.  相似文献   

9.
The use of animals in education and research is a controversial issue that involves ethical considerations. In Brazil, Act 11,794, which was approved in 2008, established the National Council on the Control of Animal Experimentation (CONCEA) and a database of institutions that use animals for research and education (CIUCA). This legislation also set out the regulations for the use of animals. In this study, we have evaluated the ethical issues involved in the use of animals for educational purposes at the Federal University of Paraná, through a qualitative-quantitative analysis that relied on written questionnaires. Our objective was to find out the opinions of students and staff from different academic fields, and at different stages in their professional development, on the use of animals for educational purposes. The study involved 101 students and 20 lecturers (i.e. tenure-track professors and all those who teach the students) in Biology, Pharmacology, Medicine and Veterinary Medicine. Approximately half of the students (45.5%) did not know the legislation that regulates the use of animals in education, and most of the lecturers believed that learning goals could not be achieved with alternative methods. Only 38.9% of the lecturers and 31.9% of the students trusted the usefulness of alternative methods. Furthermore, recent graduates were as unaware of the legislation, as were students in the first two years of their university courses. These results suggest that it is necessary to considerably expand the discussion on alternatives to animal use in the academic environment.  相似文献   

10.
Antibodies to human T-cell lymphotropic virus-1 and 2 (HTLV-1 and 2) were tested in 259 inhabitants (98 males and 161 females) of four villages of the Marajó Island (Pará, Brazil) using enzyme immunoassays (ELISA and Western blot). Types and subtypes of HTLV were determined by nested polymerase chain reaction (PCR) targeting the pX, env and 5 LTR regions. HTLV-1 infection was detected in Santana do Arari (2.06%) and Ponta de Pedras (1%). HTLV-2 was detected only in Santana do Arari (1.06%). Sequencing of the 5 LTR region of HTLV-1 and the phylogenetic analysis identified the virus as a member of the Cosmopolitan Group, subgroup Transcontinental. Santana do Arari is an Afro-Brazilian community and the current results represent the first report of HTLV-1 infection in a mocambo located in the Brazilian Amazon region.  相似文献   

11.
12.
The Parus guild (Parus spp., Sitta, Certhia, and Regulus) is distributed as a complex mosaic within the Danish archipelago, with from one to eight species on different islands. We assessed the roles of island isolation, island size, and interspecific competition in determining the breeding species compositions of this guild on 53 Danish islands. Small, isolated islands supported fewer species than larger, nearshore islands. These effects, however, were largely restricted to a few sedentary species (P. cristatus, P. palustris, S. europaea) that are known to be poor dispersers/colonizers. In some cases, these three species were also absent from large, nearshore islands with suitable habitat, suggesting that habitat availability was not always responsible for the absence of a species. Monte Carlo simulations suggested that the pattern of species presence/absence was not a result of interspecific interactions. Thus, although a number of previous studies have documented interspecific competition among members of the Parus guild, our results suggest that such competition is not responsible for the unusual pattern of species distribution within the Danish archipelago. Received: 28 October 1996 / Accepted: 7 February 1997  相似文献   

13.
With the purpose of analyzing the horizontal distribution of the zooplankton community of the Tucuruí Reservoir in the State of Pará, Brazil, collections were made at 16 stations during August 1988. The stations cover the regions called Caraipé (C), Ara?agi (B) and Arar?o (A), and represent the different compartments of this ecosystem in regard to the morphometry and the presence or absence of "flooded forest". Our findings showed the existence of three compartments with different limnological characteristics determined as a function of the system's morphometry, a factor that may have influenced the horizontal circulation of the reservoir's water and, consequently, led to physical, chemical and biological differences at each of the sampled stations. All the stations presented physical and chemical stratification and layers of total anoxia or reduced concentrations of oxygen dissolved at depths corresponding to the limit of the euphotic zone. With regard to the zooplankton, a differentiated distribution that was mainly quantitative was found among the compartments (density of organisms and proportion among the species) in the case of Cladocera and Copepoda, and basically qualitative in the case of Rotifera. On the other hand, the greatest densities of organisms for all the groups were recorded at the Caraipé stations. As for the spatial distribution, some species were more restricted or more abundant at given stations. Among the Cladocera, there was a greater abundance of Moina minuta, Bosmina hagmani and Bosminopsis deitersi at the Ara?agi stations, while C. cornuta intermedia, C. cornuta rigaudi and C. cornuta cornuta were more plentiful in the Caraipé and Diaphanosoma birgei in the Arar?o. Among the Rotifera, Trochosphaera aequatoriales and Lecane proiecta, Ascomorpha ecaudis, besides Polyartha cf vulgaris were restricted, respectively, to the Caraipé, Ara?agi and Arar?o stations, while the others, such as Keratella americana and Collotheca sp., were more broadly distributed. As regards Copepoda Calanoida, the dominating species was found to be Notodiaptomus maracaibenses, followed by Notodiaptomus henseni and Argyrodiaptomus azevedoi. The most abundant Cyclopoda species was Thermocyclops minutus, although Thermocyclops decipiens, Mesocyclops longisetus, Mesocyclops meridianus e Metacyclops sp. were also found.  相似文献   

14.
This paper reviews research pertaining to the problem of speciation of the finches on the Galápagos archipelago carried out by assistants, several colleagues, Peter Grant and myself. I give a brief history of the radiation, examine the process of divergence by natural selection over time, and then consider the nature of the reproductive barrier to gene flow between closely related species. Fluctuating climatic conditions have produced a continuously changing ecological landscape and altered feeding conditions for the finches over the last 30 years. Finch populations tracked these changes by natural selection and evolutionary responses to the main events. At each event significant morphological change occurred from one generation to the next generation. As a consequence of these accumulated changes, the mean bill shape and body size of the Geospiza fortis and G. scandens populations differed markedly from 1973 to 2002. Song, a learned culturally transmitted trait, acted as a barrier to reproduction between these species. Rare incidences of misimprinting on song led to hybridization and introgression. Low levels of gene flow from one species to another increased genetic variation on which selection acted. Although the major driving force of diversification was ecological change, the process of diversification involved a subtle interplay between ecology, genetic evolution and learned culturally transmitted traits. An important message for conservation is that neither the environment nor species are fixed entities, therefore a wise strategy for conserving endangered species should keep them capable of further change.  相似文献   

15.
Natural mycoflora associated with fumonisins were analyzed in 150 samples of freshly harvested corn from Central-Southern, Central-Western and Northern regions of the State of Paraná, Brazil and correlated to climatic conditions. The corn samples were frequently contaminated with Fusarium sp.(98.7 to 100%) and Penicillium sp. (93 to 100%), when compared to Aspergillus sp. (not detected to 27.7%). The highest contamination with potentially mycotoxigenic fungi occurred in corn harvested in the Central-Western region, where total mould and yeast counts ranged from 5.5 × 103 to 5.2 × 106 CFU/g, with 98.7% contaminated byFusarium sp. and 93% by Penicillium sp. In this region F. moniliforme (F. verticillioides) was the predominant Fusariumsp., and was isolated in 85.9% of the samples. Aspergillus sp. was isolated from 27.7% samples. FB1 was detected in 100% of the samples (mean of 2.39 g/g) and FB2 in 97.7% (mean of 1.09 g/g). Fumonisins were also detected in all samples from Northern region, with mean of 4.56 g/g (FB1) and 2.20 g/g (FB2).Considering 1.0 g/g as the threshold, 72% of the corn samples from the Central-West and 92% from the North were contaminated with concentrations above this value, in contrast to a 18.5% contamination rate from Central-Southern samples. Between corn planting to harvesting season, the average maximum temperature and relative humidity were 26 °C and 77.1%(Central-Southern), 27 °C and 69% (Northern)and 29.9 °C and 89.1% (Central-Western).Therefore, the higher fumonisins contamination of corn from Northern region when compared to the Central-South were due to the differences in rainfall levels (92.8 mm in Central-Southern, 202 mm in Northern) during the month preceding harvest.This revised version was published online in October 2005 with corrections to the Cover Date.  相似文献   

16.
Notes on the Poaceae of the Robinson Crusoe (Juan Fernández) Islands, Chile, Brittonia 54: 154–163. 2001.—Poaceae in the Robinson Crusoe (=Juan Fernández) Islands number 53 species in 32 genera, of which 9% of the species are endemic, 9% indigenous, and 81% adventitious. The endemic taxa (and their conservation status) are:Agrostis masafuerana (rare),Chusquea fernandeziana (not endangered),Megalachne berteroana (not endangered),M. masafuerana (not endangered), andPodophorus bromoides (extinct).Megalachne andPodophorus are endemic genera. Comparisons with Poaceae in the Bonin and Volcano Islands, Canary Islands, Galápagos Islands, and Hawaiian Islands show different levels of endemism: number of endemic taxa, respectively, 5, 10, 12, 40; percent specific endemism, 8, 6, 21, 19. No endemic genera occur.Anthoxanthum odoratum, Avena barbata andHordeum murinum are noxious weeds in the Robinson Crusoe Islands. Many adventives are shared among floras of the archipelagos, with the highest ties of Robinson Crusoe being to the Canaries (53% of total Poaceae known in Juan Fernández) and the Hawaiian Islands (47%). Low levels of adventives occur within the Bonin (5%) and Galápagos (7%) Islands. In contrast, there are many endemic genera of Asteraceae in these same archipelagos: Bonin and Volcano Islands (1), Canary Islands (8), Galápagos Islands (5), and Hawaiian Islands (6); percent of specific endemism is also higher (20, 53, 54 and 56, respectively). Hypotheses for greater levels of endemics among oceanic island Asteraceae include more efficient dispersal mechanisms by wind and birds, animal pollination systems that result in greater degrees of geographic populational genetic isolation, and a vascular cambium that offers enhanced growth-form evolutionary opportunities.  相似文献   

17.
We analyzed, by env and gag heteroduplex mobility assay, 149 human immunodeficiency virus (HIV-1) positive samples collected in Ceará during the year 2000. The prevalence of subtype B was 81.2% and the prevalence of subtype F and B/F recombinants were both 2.7%. Eight (5.4%) and 12 (8%) out of 149 samples showed indeterminate results in the env and gag analysis respectively. By FokI restriction fragment length polymorphism, 34% of the subtype B samples were identified as the typical Brazilian subtype B.In the present study, we identified HIV-1 subtype F and B/F in Ceará for the first time. Our results contribute to the understanding of HIV in Brazil, and may prove useful for the development of vaccine candidates.  相似文献   

18.
Two sediment cores from the eastern coastal region of Marajó Island, Pará State, northern Brazil have been studied by pollen analysis to reconstruct late Holocene mangrove dynamics and environmental changes. Seven AMS radiocarbon dates provide time control. Mangrove vegetation became established at the Barra Velha site at about 2750 B.P. (2880 cal B.P.) and at the Praia do Pesqueiro site at about 650 B.P. (670 cal B.P.). Rhizophora was the dominant mangrove tree throughout the recorded period, while Avicennia and Laguncularia were rare. Existing remnants of the former coastal Amazon rain forest were replaced by mangrove in the Barra Velha area between about 2750 and 740 B.P. (2880–760 cal B.P.) and at Praia do Pesqueiro area between about 650 and 530 B.P. (670–540 cal B.P.), suggesting a rise in relative sea level or, alternatively, an increase in discharge from the river Amazon. Areas of coastal shrub and herb vegetation, the so-called restinga vegetation, also became slightly reduced during the late Holocene. The largest area of mangrove at the two sites suggests that the highest sea level was probably reached during the last 200–250 years. The only evidence of human activity at the two sites is an indication of cattle pastureland at the Barra Velha area during the last decades.  相似文献   

19.
L. Yiming  J. Niemelä  L. Dianmo 《Oecologia》1998,113(4):557-564
Because of their poor dispersal ability, amphibians are well suited for testing the selective extinction theory on islands. Amphibian fauna in the Zhoushan archipelago, China, exhibit a high level of nestedness (C = 0.893), and the species number is lower on islands than on similar sized areas on the mainland. No correlation was found between island-specific species richness and the nearest distance from a larger island, distance from the mainland or density of human population. These results suggest that no amphibian colonisation has occurred in the archipelago since island isolation 7000–9000 years ago. Furthermore, the results imply that selective extinction contributes to the nestedness of amphibians in the Zhoushan archipelago. The incidence of a species on the islands is significantly correlated with log area of the smallest island occupied by the species and the number of provinces on the Chinese mainland in which the species occur. However, there is no correlation with average body length of adults and island occurrence. It is concluded that (1) the area of the smallest island occupied by a species is a good estimate of the minimum area for a viable population of the species and a good predictor of species incidence on islands, (2) species with a restricted distribution range are more vulnerable to extinction from islands than those with a wide distribution range and (3) the effect of body size on occurrence on the islands is uncertain, and may be specific to the archipelago and taxa studied. The observed nestedness of amphibian assemblages has two implications for conservation: (1) not only can all the species found in several small reserves be found on a large reserve of the same total size, but additional species can be found on the single large reserve; (2) for a reserve to maintain viable populations of all species in a region it should be at least as large as the smallest island occupied by the most vulnerable species. Received: 16 December 1996 / Accepted: 22 September 1997  相似文献   

20.
In this article data on household food consumption is used to further understanding of subsistence strategies in three Caboclo populations on Marajó Island, Amazonia, Brazil. Data were collected using participant observation and 24-hour food recalls in 16 households for 7 consecutive days during the rainy (March) and dry (July) seasons. Marajó-Açu households (n = 6) had the highest levels of energy and protein intake relative to recommendations. This was probably related to their successful integration into the prosperous acai (a palm fruit) market of the riverine area. Praia Grande households (n = 6) had the lowest values for energy intake (rainy season), which supports the authors' ethnographic observations of some instability in the subsistence system of this population. Paricatuba households (n = 4) exhibited intermediate values of energy and protein intakes, but less seasonal variation in consumption than the other two populations. Despite the differences observed, food consumption does not appear to be a major limitation for any of the three populations. The data support recent hypotheses concerning the concomitant and multiple use of várzea (floodplain) and terra firme (upland) environments by the Caboclos and integration into the local market economy as the central strategies in dealing with the so-called socioenvironmental constraints of the Amazonian floodplain.  相似文献   

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