Parasitism of Hylodes phyllodes (Anura: Cycloramphidae) by Hannemania sp (Acari: Trombicuudae) in an area of Atlantic Forest, Ilha Grande, southeastern Brazil

We studied some parameters of the parasitism by the mite Hannemonia sp. on the endemic frog Hylodes phyllodes in the Atlantic Forest of Ilha Grande (Rio de Janeiro State, Brazil). Prevalence, mean abundance, mean intensity and total intensity of infestation, body regions infected, and host sexual differences in parasitism rate of the larvae of Hannemania sp. on individuals of H. phyllodes were assessed. Prevalence was 86.5% (N = 37; total of 1,745 larvae of Hannemania sp) for male hosts and 91.7% (N = 12; total of 330 larvae) for female hosts, with no significant difference between the sexes. Overall prevalence of Hannemania sp. on H. phyllodes was 87.7%. Mean intensity of infestation in males (54.5 +/- 42.5; range 1-173 larvae) was higher than in females (29.9 +/- 47.6; range 1-166). We conclude that the rates of intensity, abundance, and prevalence of Hannemania larvae parasitizing Hylodes phyllodes at Ilha Grande were considerably high, suggesting that this species of anuran constitutes a relevant host for this mite species to complete its life-cycle in the area. Differences between males and females in infestation rates probably reflect their differential use of space in the forest.     

Ecology and host specificity of laelapine mites (Acari: Laelapidae) of small mammals in an Atlantic forest area of Brazil

Mesostigmatic mites of the Laelapinae Berlese, 1892 (Acari: Laelapidae) are nidicolous arthropods that commonly occur in the fur of Neotropical small mammmals. In this 2-yr study, the laelapine acarofauna associated with the small mammal community in an area of Atlantic forest on Ilha Grande, Rio de Janeiro State, was examined, including observations on patterns of host specificity, mite dispersal, ecology, and food habits. A total of 1,347 laelapines was sampled from the pelage of 6 species of small mammals (Marmosops incanus, Nectomys squamipes, Oryzomys russatus, Rhipidomys n. sp., Oxymycterus dasytrichus, and Trinomys dimidiatus), all of which occurred exclusively in monoxenous associations with their hosts. No evidence of a blood meal was observed in the gut of the mites. With the exception of the 2 species of Tur, mite populations on hosts were entirely or nearly restricted to adult females. These results, together with some morphological characteristics of laelapines, reinforce the hypotheses that Neotropical laelapine mites are not ectoparasitic, and that females disperse by phoresy.     

Habitat disturbance and small mammal richness and diversity in an Atlantic rainforest area in southeastern Brazil.

Since disturbance is an important ecological factor affecting species diversity in natural environments, the increasing human occupation rate in Brazilian Atlantic rainforest, which supports about 50% of Brazil's human population, has resulted in intense habitat degradation and fragmentation. Within this rainforest, animal and plant species have been lost at a high rate, and biological and diversity is presently vulnerable. Various animals community studies along a gradient of environmental disturbances have shown that the highest species diversities occur in habitats with intermediate levels of disturbance frequency and intensity. In the present study, which was carried out in the Atlantic forest of Ilha Grande (23 degrees 11' S and 44 degrees 12' W), an island located on the southern coast of Rio de Janeiro State, southeastern Brazil, we estimated species richness, diversity, and abundance of small mammals in three forest areas having different disturbance levels. This was done, in each of these areas and in an anthropic area that they surround, by establishing trails 200 m long, in which points were marked at 20 m intervals. The work involved a total effort of 4800 trap/nights. We also measured some habitat variables at each site in order to evaluated their disturbance levels. Our data showed that the two most conserved forests had the lower species richness and small mammal diversity, while in the anthropic area wild species were absent. The forest with an intermediary level of disturbance showed higher values for species richness and diversity, with the anthropic area presenting the highest disturbance level.     

Spatial distribution and abundance of nonindigenous coral genus Tubastraea (Cnidaria, Scleractinia) around Ilha Grande, Brazil.

The distribution and abundance of azooxanthellate coral Tubastraea Lesson, 1829 were examined at different depths and their slope preference was measured on rocky shores on Ilha Grande, Brazil. Tubastraea is an ahermatypic scleractinian nonindigenous to Brazil, which probably arrived on a ship's hull or oil platform in the late 1980's. The exotic coral was found along a great geographic range of the Canal Central of Ilha Grande, extending over a distance of 25 km. The abundance of Tubastraea was quantified by depth, using three different sampling methods: colony density, visual estimation and intercept points (100) for percentage of cover. Tubastraea showed ample tolerance to temperature and desiccation since it was found more abundantly in very shallow waters (0.1-0.5 m), despite the fact that hard substratum is available at greater depths at all the stations sampled. At most sites, 1 to 5 colonies per 0.25 m2 were found most frequently, but occasionally more than 50 colonies were found per 0.25 m2, indicating a somewhat gregarious spatial distribution for this coral. The coral Tubastraea was found to occupy slopes of every possible angle in the Canal Central of Ilha Grande, but more colonies were found occupying slopes of 80 to 100 degrees. Therefore, its insensitivity to angles of recruitment and its tolerance for different depths makes it an organism with great ecological tolerance, with a potential to colonize new areas and increase its current range in Brazil's coastal waters.     

Vertical stratification and development aspects of phlebotomine sand flies (Diptera: Psychodidae) in an area of Atlantic Forest tree species in a metropolitan region in northeastern Brazil.

In the state of Rio Grande do Norte in northeast Brazil, cases of visceral leishmaniasis (VL) occur mainly in the periurban areas of the city of Natal. Lutzomyia longipalpis Lutz & Neiva 1912 (Diptera: Psychodidae), a vector of Leishmania chagasi (Protozoa: Trypanosomatidae) to humans, is found throughout the state. Flora and fauna influence the distribution of sand fly species, whose horizontal or vertical stratification can be used as a parameter for identifying potential vectors, considering the presence of vertebrate hosts in the area. The purpose of this study was to obtain information about the vertical stratification of phlebotomine sand flies in an endemic area of leishmaniasis in Rio Grande do Norte, and associate it with the presence of other animals in the peridomiciliary environment as well as to analyze, under laboratory conditions, aspects of L. longipalpis reproduction in wild females. The sand flies were captured with light traps hung at different heights in species of Atlantic Forest trees and in a peridomiciliary environment in animal shelters. The traps were placed between 17:30 and 6:00 of the following day, in a peridomiciliary and extradomiciliary area of a forest fragment in both dry and rainy months. In the extradomiciliary environment, the traps were installed at 1, 3 and 5 m above the ground. The biological cycle of L. longipalpis was followed from the eggs of 200 wild females. Specimens of L. lenti, L. walkeri, and L. migonei were captured. The comparison and statistical analysis showed that L. longipalpis is more abundant at a height of 3 m and L. evandroi at 1 m. In the animal shelters (chickens, horses, and armadillos), we captured mainly specimens of L. longipalpis and L. evandroi. The duration of the biological cycle of L. longipalpis was approximately 38 days at a temperature of 28 degrees C.     

Yeast communities as descriptors of habitat use by the Drosophila fasciola subgroup (repleta group) in Atlantic rain forests

Yeast communities associated with four species of the Drosophila fasciola subgroup (repleta group) in tropical rain forests were surveyed in an abandoned orchard, and rain forest sites of Rio de Janeiro and Ilha Grande, State of Rio de Janeiro, Brazil. Adult flies of Drosophila carolinae, Drosophila coroica, Drosophila fascioloides and Drosophila onca frequently carried Candida colliculosa, Geotrichum sp, Kloeckera apiculata and a Pichia membranaefaciens-like species. The most frequent yeasts in the crop of flies included Candida collicullosa, C. krusei, Pichia kluyveri and a P. membranaefaciens-like species. The physiological abilities and species composition of these yeast communities differed from those of other forest-inhabiting Drosophila. The narrow feeding niches of the fasciola subgroup suggested the use of only part of the substrates available to the flies as food in the forest environment, as noted previously for cactophilic Drosophila serido (mulleri subgroup of the repleta group) in a sand dune ecosystem. The cactophilic yeasts that were isolated have not been previously found in forests. The fasciola subgroup probably used epiphytic cactus substrates as breeding and feeding sites in the forest. The physiological profile of yeasts associated with the fasciola flies was broader than that of yeasts associated with the cactophilic Drosophila serido, suggesting that the fasciola subgroup represents an older lineage from which the South American repleta species evolved.     

Patterns of gall-forming in Ossaea confertiflora (Melastomataceae) by Lopesia brasiliensis (Diptera: Cecidomyiidae) in an area of Atlantic Rainforest in southeastern Brazil

Patterns of galling by the gall midge Lopesia brasiliensis (Diptera: Cecidomyiidae) were studied in Ossaea confertiflora (Melastomataceae) in an Atlantic forest site at Ilha Grande, RJ. Out of the 81 plants surveyed, 55 (67.9%) bore galls. The number of galls per galled individual ranged from 1 to 261 and 94.4% of the galls were in leaves. The number of galls per galled leaf varied from 1 to 25. Total gall number was positively correlated with plant height. Larger and more ramified plants tended to have a smaller percentage of their leaves with galls and a lower density of galls per leaf than smaller plants. Plants that were close to other individuals of the same species tended to have more galls per leaf than relatively isolated plants. The observed patterns may be linked to strategies of optimization in the use of resources (i.e. oviposition sites) and predation avoidance by the gall midges.     

Estimates of forest floor litter frog communities: A comparison of two methods

Estimates of forest leaf litter frog density, mass, richness and diversity given by the widely used 8 m × 8 m large plot method (LPM) were compared with estimates obtained by a newly proposed method (small 2 m × 1 m plots with leaf removal; SPLR). The study site was an undisturbed area of the Atlantic Rainforest of Ilha Grande, an island located in the south of Rio de Janeiro State, Brazil. Twenty‐four LPM (totalling 1536 m² of forest floor) and 90 SPLR (totalling 180 m² of forest floor) were performed. The estimates obtained by the two methods differed markedly, indicating that even using a much smaller sampling area (11.7% of that of LPM), SPLR gave frog density estimates six times higher, and frog mass estimates approximately 2.5 times higher than estimates provided by LPM. The species richness and diversity obtained by the two methods were similar, despite the fact that the total area sampled with SPLR was much smaller. These data suggest that LPM may underestimate the abundance and biomass of leaf litter frogs in a given area.     

Natural history of the lizard Enyalius brasiliensis (Lesson, 1828) (Leiosauridae) from an Atlantic forest of southeastern Brazil.

Information on the ecology of lizard species from the Brazilian Atlantic Forest is scarce and almost nothing is known about the ecology of lizards of the genus Enyalius. In this study, we provide information about some aspects of the natural history of E. brasiliensis from an area of Atlantic Forest in Ilha Grande, RJ. Enyalius brasiliensis (N = 15) feeds mainly on arthropods. The most frequent food items were insect larvae, orthopterans, and ants; in terms of volume, larvae and termites were the most important food items; ants and termites were the most numerous prey categories. Two females were reproductive (one had 10 and the other, five vitellogenic follicles); the smallest measured 92.4 mm in SVL. Seven lizards were found on forest leaf litter. The other microhabitats used were vines, fallen logs, branches, and a crevice on a slope.     

Reproductive cycle of Pitcairnia flammea Lindl. (Bromeliaceae/Pitcairnioideae) in an insular Atlantic rainforest area in southeastern Brazil

We studied for 6 years the reproductive cycle of the bromeliad Pitcairnia flammea in the Atlantic Rainforest of Ilha Grande, an island located in the south of Rio de Janeiro state, southeastern Brazil. We marked 150 adult individuals of the species, for which we monthly observed the occurrence of reproductive characteristics. The phenological attributes were related to environmental factors such as photoperiod, rainfall and temperature. Additionally, we estimated a mortality rate that was related to the rainfall in the area. P. flammea possesses a seasonal reproduction pattern, with a relatively fixed and well-defined time span during the winter dry period; flowering precedes fruiting by approx. 1 month. Due to the occurrence of P. flammea preferably on boulders of river channels and banks mortality of the plants is highest when floods from strong rainfall remove the plants mechanically from their growing places.     

海南五指山森林的垂直分布及其特征

本文探讨了海南五指山森林垂直分布及其特征．并根据五指山自然保护区的６００ｃｍ２样地调查材料,连同区内一些路线调查材料统计结果,计有维管束植物９９８种,５７６属,１７８科;按照植物地理成份分析,指出以樟科、桃金娘科、壳斗科、棕榈科等科、属、种为主的五指山热带、亚热带植物属占总、属数的８９％是很高的。根据调查材料,五指山森林可划分为３个垂直带与１１个植被群系,也就是Ⅰ．热带雨林带,一、热带常绿季雨林：１：荔枝,毛丹群系;Ⅱ．热带山地雨林带：一、低山雨林：（一）低山青梅雨林;１,青梅,蝴蝶树群系：２．鸡毛松．公孙锥群系：（二）沟谷雨林：１．尖叶杜英,海南柿群系;（三）低山枫香林：１．枫香．鸭脚木群系．二、中山雨林：（一）中山针阔叶雨林：１．陆均松．岭南青同群系;２．银背锥．白花含笑群系;３．罗浮锥,海南蕈树群系;Ⅲ．中山矮曲林带：一、中山矮曲林：１．硬壳柯,厚皮香群系;２．少药八角．肖柃群系;二、山顶矮林：１．红脉南烛,南华杜鹃群系。五指山森林垂直分布规律与特点：１．乔木树种多样性随着海拔升高而递减;２．温带树种的数量随着海拔升高而递增：３．青梅天然分布的海拔高度为海南各林区之冠。     

Bioinvasion in a Brazilian Bay: Filling Gaps in the Knowledge of Southwestern Atlantic Biota

Background

Biological invasions are a major cause of global species change. Nevertheless, knowledge about the distribution and ecology of introduced species is regionally biased, and many gaps in knowledge exist for most developing countries.

Methodology/Principal Findings

To study the zoobenthos on the hard substratum of the Ilha Grande Bay, a survey was conducted on both natural and artificial substrata at three depths and seven sites. The species recorded were classified as native, cryptogenic or introduced. Multivariate analyses were conducted to assess the prevalence of introduced species in these communities and to compare the distribution of species on natural and artificial substrata of this bay to identify possible discrepancies in habitat use. Of the 61 species, 25 were cryptogenic, 10 were introduced and 26 were native. Similar numbers of introduced species were found on both natural and artificial substrata, though the community composition was significantly different between them. We also compared the species composition of the Ilha Grande Bay survey to other inventories taken around the world. The highest similarities were found between the Ilha Grande Bay inventory and the Atlantic coastal region (Tampa Bay, USA and the Gulf of Mexico), American Samoa and Pearl Harbor (USA) inventories.

Conclusions/Significance

This study presents the first published comprehensive list of hard substratum sessile marine invertebrate species in a Brazilian bay. The high percentage of cryptogenic species reveals gaps in both zoological records and information on introduced species for the Brazilian coast. The introduced species successfully colonized different sites in the Ilha Grande Bay, including both natural and artificial substrata. In addition, we find that artificial structures may not be good surrogates for natural rocky shores and may represent an ecological threat. Comparisons with other inventories suggest a history of broad-scale invasion, though more evidence is needed to support this conclusion.     

Seed Dynamics in Relation to Gaps in a Tropical Montane Rainforest of Hainan Island, South China： （I） Seed Rain

Seed dynamics is an important part of stand dynamics in forest ecosystems. In this paper, 26 gaps were randomly selected to study the influence of gaps on the spatial and temporal patterns of seed rains in a tropical montane rainforest of Hainan Island, South China. Three zones for each gap, including outside gap zone （Non-gap）, transitional gap zone （EG-CG）, and central gap zone （CG）, were designed, and fourseed traps （each lm x lm in size） were placed in each zone. Seed rains were collected by these traps every 10 days from June 2001 to May 2002. Seed rain varied greatly with season and generally exhibited a pattern of unimodal change during the study period： seed abundance and species richness were both greater in the wet season than in the dry season. Gaps significantly influenced the temporal patterns of both species richness and density of seed rains. Gaps had no significant influences on the spatial distribution patterns of seed rain species richness, but significantly affected the spatial distribution pattern of seed rain densities. Among the three different zones of gaps, the outside gap zone generally received more seeds inputs than the two other gap zones.     

Seasonal changes in general activity, body mass and reproduction of two small nocturnal primates: a comparison of the golden brown mouse lemur ( Microcebus ravelobensis) in Northwestern Madagascar and the brown mouse lemur ( Microcebus rufus) in Eastern Madagascar

To investigate for the first time the relationship between contrasting patterns of seasonal changes of the environment and activity, body mass and reproduction for small nocturnal primates in nature, we compared a population of golden brown mouse lemur (Microcebus ravelobensis) in a dry deciduous forest of northwestern Madagascar and of the brown mouse lemur (Microcebus rufus) in an evergreen rain forest of eastern Madagascar. Both species live under similar photoperiodic conditions. Golden brown mouse lemurs (GBML) were active during the whole period (May to December) irrespective of changing environmental conditions. In contrast, a part of the population of brown mouse lemurs (BML) showed prolonged seasonal torpor, related to body mass during periods of short day length and low ambient temperatures. Differences between species might be due to differences in ambient temperature and food supply. Body weight and tail thickness (adipose tissue reserve) did not show prominent differences between short and long photoperiods in GBML, whereas both differ significantly in BML, suggesting species-specific differences in the photoperiodically driven control of metabolism. Both species showed a seasonal reproduction. The rate of growth and size of the testes were similar and preceded estrous onset in both species suggesting a photoperiodic control of reproduction in males. The estrous onset in females occurred earlier in GBML than in BML. Estrous females were observed over at least 4 months in the former, but in only 1 month in the latter species. Intraspecific variation of estrous onset in GBML may be explained by body mass. Interspecific variation of female reproduction indicates species-specific differences in the control of reproduction. Thus, environmentally related differences in annual rhythms between closely related small nocturnal lemurs emerged that allow them to cope with contrasting patterns of seasonal changes in their habitats.     

广西特有杜鹃花种群特征研究

(1 )广西特有杜鹃花在水平地带性植被典型常绿阔叶林、季风常绿阔叶林和季节性雨林都有分布 ,但主要分布在典型常绿阔叶林垂直带谱上的针阔混交林、常绿落叶阔叶混交林和山顶矮林 ;(2 )从 1 2种广西特有杜鹃花样方资料统计看 ,乔木层中最常见的科是壳斗科、山茶科和樟科等 ,这些科都是我国亚热带典型常绿阔叶林代表科 ,这就同样说明了广西特有杜鹃花的主要分布区域系在亚热带山地常绿阔叶林的垂直带谱中 ;(3 )绝大多数广西特有杜鹃花种类分布的生境条件十分恶劣 ,这间接说明了广西特有杜鹃花多是一些古老的残遗种 ;(4 )广西特有杜鹃花同其他杜鹃花一样 ,均需要土壤呈酸性、气温偏低 ,相对湿度大于 80 %的环境条件。这些特点在我们引种杜鹃花时必须加以考虑。     

Patterns in the vertical structure of the tropical lowland rain forest of Los Tuxtlas,Mexico

The vertical structure of one hectare of tropical rain forest was studied at Los Tuxtlas, State of Veracruz, Mexico. The structure was analysed at various scales of analysis, using different methodologies e.g. profile diagrams (0.1 ha) and vertical structure diagrams (1 ha). All profile diagrams suggested presence of stratification to some extent. However, simultaneous evaluation of several adjacent profile diagrams showed that the use of one profile diagram only can be very misleading: gaps or layers apparent in a diagram did usually not reflect gaps or layers that could be recognized in the field.Structure diagrams of abundance, basal area and crown cover showed that this forest community is not stratified, with the exception of an understorey layer below 7.5 m dominated by palms. The vertical structure was described using arbitrarily chosen height intervals. From the forest floor to the canopy top basal area, percentage of deciduous species (and individuals), and percentage of compound-leaved species (and individuals), increased, but total number of individuals and number of species decreased. Leaf sizes tended to decrease in the same direction, and crown cover was approximately evenly distributed. Species from different families dominated different parts along the vertical plane. It is concluded that the vertical structure of tropical rain forest can best be described as a complex gradient, involving many community features. Stratification can best be emphasized as a special case of such a gradient.     

A field study of the socio-ecology of the Goeldi's monkey (Callimico goeldii) in northern Bolivia

A 5-month field study on both the distribution and ecology of Callimico goeldii was carried out in the seasonally dry rain forest of north-western Bolivia. The species was found to be very sparsely distributed (approximately one group per 4 km2) in isolated groups of about 6 animals throughout the study area. Callimico was found to associate a great deal with two species of Saguinus that inhabit the same region in greater densities. It appears to be a habitat specialist, preferring low-lying and damp, but well-drained, bamboo forest and spending nearly all its time within 3 m of ground level, travelling mainly by vertical clinging and leaping. We believe that this ecological specialisation accounts for the species' discontinuous micro-distribution, and that this in turn is related to Callimico's distinctive pattern of social organisation.     

海南岛尖峰岭地区热带植被生态系列的研究

 本文通过对海南岛尖峰岭地区热带植被随环境条件递变而变化的分析,反映出在一较短的水平距离内植被变化的多样性,并通过群落生态学方法的分析,说明尖峰岭地区的植被在种类组成、多样性、群落外貌等方面都具有较典型的热带性质,但在群落的结构方面则比典型的热带雨林逊色,说明它是地处热带北缘和在季风气候影响下的必然结果。用重要值方法来描述热带植物群落,其结果较为理想。研究该地区热带植被的特点,对认识、了解我国的热带植被和经营热带林等方面,提供了一些理论依据。     

Vertical oviposition activity of mosquitoes in the Atlantic Forest of Brazil with emphasis on the sylvan vector,Haemagogus leucocelaenus (Diptera: Culicidae)

This study aimed to assess the vertical patterns of oviposition and temporal changes in the distribution of mosquito species in an area of the Atlantic Forest in Rio de Janeiro State, Brazil, and in particular, the behavior and oviposition of potential yellow fever virus vectors. Mosquito samples were collected from the Ecological Reserve Guapiaçu (REGUA, Brazil), which includes a somewhat disturbed forest, with a large diversity of plants and animals. In all, 5,458 specimens (ten species from seven genera) were collected. Haemagogus leucocelaenus was the most frequently captured species, representing 73% of the specimens collected. Species richness and diversity were the highest in the samples collected from the ground‐level ovitraps and decreased with height. Species composition also differed significantly among heights. The largest species differences were detected between ovitraps set at the ground level and those set at 7 m and 9 m; Hg. leucocelaenus, Limatus durhamii, and Limatus paraensis contributed most to these differences. Sampling month and climatic variables had significant effects on species richness and diversity. Species diversity and richness decreased with height, suggesting that the conditions for mosquito breeding are more favorable closer to the ground. Species composition also showed vertical differences.