The fragmented Atlantic rain forest of Brazil: size, shape and distribution of forest fragments

The geographical characteristics of a total of 1839 forest fragments surrounded by sugar cane fields were studied in the Brazilian Atlantic rain forest region of the northeastern state of Pernambuco. The size and shape of the fragments as well as inter-fragment distances and the effects of varying edge width were examined using a geographical information system. The analyses show that the fragments are relatively small and close to each other. Approximately 48% of the rain forest fragments are <10 hectares, while only about 7% are >100 hectares. Forest fragments are close to each other, as fragments located 50m or less apart formed groups that included ca. 50% of the total forest area. At 350m inter-fragment distance, 98% of the rain forest area was included in groups of fragments. Due to the small size and irregular shape of the fragments, the total area of edge zone exceeds that of the interior habitat when the edge width is ca. 60m. At an edge width of 300m ca. 94% of the total fragment area is edge zone. For conservation purposes, ways of establishing networks of forest fragments connected by corridors and stepping stone fragments are demonstrated using GIS. Simulations using these techniques show that reforestation of sugar cane fields between the forest fragments would considerably increase the area of interior forest habitat and connectivity between fragments.     

Host-ectoparasite specificity in a small mammal community in an area of Atlantic Rain Forest (Ilha Grande, State of Rio de Janeiro), Southeastern Brazil

The analyses of the ectoparasite species associated with a small mammal community on Ilha Grande, a coastal island in southern of the state of Rio de Janeiro, Brazil, evaluated the level of host-ectoparasite specificity. Was used the Jaccard index for qualitative data to analyse the similarity. The lowest value of similarity occurred between Proechimys iheringi and Marmosops incanus and between Sciurus aestuans and Nectomys squamipes (Cj=0.08) and the highest between P. iheringi and Oxymycterus sp. (Cj=0.33). This index showed a low value of similarity across the ectoparasite community. The only exception from this pattern of high host specificity occurred with P. iheringi and Oxymycterus sp., which shared five species of ectoparasites. The similarity values, for most of the cases, is smaller than 0.2.     

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.     

Distyly and sequential pollinators of Psychotria nuda (Rubiaceae) in the Atlantic rain forest, Brazil

Reciprocal herkogamy is known to promote intermorph-pollination in distylous species, which are generally self- and intramorph-incompatible. Legitimate crossing rates are also influenced by pollinator foraging strategy, which determines most of the pollen flow in natural populations. This study reports on the floral morphology, compatibility relations and pollination biology of Psychotria nuda (Cham. and Schltdl.) Wawra in the Atlantic rain forest, southeastern Brazil, based on floral measurements, hand-pollination experiments and focal observation of floral visitors. It was found that P. nuda does not present an exactly reciprocal herkogamy, however, this morphological trait in P. nuda is as good as in most of Rubiaceae. Reproductive experiments showed compatibility relations similar to those frequently observed in distylous species. The hummingbirds Ramphodon naevius and females of Thalurania glaucopis were the main pollinators of P. nuda, presenting the traplining foraging strategy, which seems to maximize intermorph crosses in P. nuda flowers. These hummingbirds pollinated P. nuda flowers sequentially throughout the flowering period.     

Two new species of <Emphasis Type="Italic">Quesnelia</Emphasis> (Bromeliaceae: Bromelioideae) from the Atlantic Rainforest of Bahia,Brazil

Quesnelia koltesii and Q. clavata, two new species of Bromeliaceae, are described and illustrated, and their affinities with related taxa are discussed. Both species are endemic to southern Bahia, occur in low population densities above 600 m elevation, and must be considered to be endangered.     

Diet of the lizard Mabuya agilis (Sauria; Scincidae) in an insular habitat (Ilha Grande, RJ, Brazil).

We examined the stomach contents of 21 specimens of Mabuya agilis (Sauria; Scincidae) collected during February 2001 at the restinga habitat of Praia do Sul, in Ilha Grande, RJ, Brazil. Diet was composed of various types of small arthropods, with no plant material being eaten. Spiders were the most important items in the diet, followed by orthopterans. Apart from the absence of isopterans, the diet of Mabuya agilis from this insular area was similar to those of other conspecific mainland populations. This suggests that factors such as insularity and the absence of other small sympatric lizards may not have a significant effect on the feeding habits of the Praia do Sul population.     

Soil-vegetation relationships in cerrado (Brazilian savanna) and semideciduous forest, Southeastern Brazil

Several studies pointed out soil properties as the prime determinant ofcerrado (the Brazilian savanna) physiognomies, and a gradient from campocerrado (a shrub savanna) to cerradão (a tallwoodland) has been correlated with a soil fertility gradient. Based on thishypothesis, we investigated soil-vegetation relationships in thePé-de-Gigante Reserve (São Paulo State,SoutheasternBrazil). We randomly distributed 10 quadrats (10 × 10 m) oneach ofthe following physiognomies: campo cerrado, cerradosensu stricto, cerradão, andseasonal semideciduous forest, previously defined by the analysis of satelliteimages (LANDSAT-5). We sampled the woody individuals with stem diameter> 3 cm at soil level, identifying their species. In each quadrat, wecollectedsoil samples at the depths of 0–5, 5–25, 40–60, and80–100 cm, and determined pH, K, Ca, Mg, P, Al, H + Al, basesaturation, aluminium saturation, cation exchange capacity, and percentage ofsand, clay and loam. Obtained data were submitted to a canonical correspondenceanalysis (CCA) and to a detrended correspondence analysis (DCA). Our resultsshowed a clear distinction between semideciduous forest and the cerradophysiognomies, based in soil parameters. The former was related to higherconcentrations of cations and clay in the soil, while the latter was related tohigher concentrations of exchangeable aluminium in the soil surface. The threecerrado physiognomies – campo cerrado, cerradosensu stricto, and cerradão– could not be distinguished considering plant density and the analysedsoil features.     

Ecological aspects of mosquitoes (Diptera: Culicidae) in an Atlantic forest area on the north coast of Rio Grande do Sul State,Brazil

Mosquito diversity was determined in an area located on the southern limit of the Atlantic Forest on the north coast of Rio Grande of Sul State. Our major objective was to verify the composition, diversity, and temporal distribution of the mosquito fauna, and the influence of temperature and rainfall. Samplings were performed monthly between December, 2006 and December, 2008, in three biotopes: forest, urban area, and transition area, using CDC light traps and a Nasci vacuum. A total of 2,376 specimens was collected, from which 1,766 (74.32%) were identified as 55 different species belonging to ten genera. Culex lygrus, Aedes serratus, and Aedes nubilus were dominant (eudominant) and constant throughout samplings. The forest environment presented the highest species dominance (D_S=0.20), while the transition area showed the highest values of diversity (H'=2.55) and evenness (J'=0.85). These two environments were the most similar, according to the Morisita‐Horn Index (I_M‐H=0.35). Bootstrap estimates showed that 87.3% of the species occurring in the region were detected. The seasonal pattern showed a greater abundance of mosquitoes between May and October, indicating the period to intensify entomological surveillance in that area.     

Comparison of aquatic hyphomycetes communities between lotic and lentic environments in the Atlantic rain forest of Pernambuco,Northeast Brazil

Riparian forests are important to aquatic ecosystems and produce large quantities of organic matter that are recycled by the microbial community that includes microscopic fungi. The aim of this study was to unveil and compare the diversity of aquatic hyphomycetes associated to submerged leaf litter of tropical lotic and lentic environments in the Atlantic Forest of Northeast Brazil. Six sampling events were carried out in six points of two study areas: Biological Reserve “Mata da Chuva” (MC) and Environmental Protection Area “Lagoa da Mata” (LM), in Pernambuco, Brazil. Twenty three taxa of hyphomycetes were identified resulting in 87 occurrences. In the lake LM, 13 taxa of hyphomycetes were identified with 34 occurrences and in the MC (stream), 20 taxa with 53 occurrences. Ten species were common to both areas. Diversity indices and fungal biomass (ergosterol) were mostly higher in the lotic system. The fungal community analysis did not show any structure regarding sampling periods or sampling points within an area, however the two areas are different. Although the turbulence of the water is considered important for the development of these aquatic fungi, it is possible to find a diverse community of hyphomycetes and considerable fungal biomass in the lentic environment.     

Diversity and genetic structure of the Mexican endemic epiphyte Tillandsia achyrostachys E. Morr. ex Baker var. achyrostachys (Bromeliaceae)

BACKGROUND AND AIMS: The monoecious, bird-pollinated epiphytic Tillandsia achyrostachys E. Morr. ex Baker var. achyrostachys is an endemic bromeliad of the tropical dry forests of Mexico with clonal growth. In the Sierra de Huautla Natural Reserve this species shows a host preference for Bursera copallifera (Sessé & Moc ex. DC) Bullock. As a result of deforestation in the study area, B. copallifera has become a rare tree species in the remaining forest patches. This human-induced disturbance has directly affected the population densities of T. achyrostachys. In this study the genetic consequences of habitat fragmentation were assessed by comparing the genetic diversity, gene flow and genetic differentiation in six populations of T. achyrostachys in the Sierra de Huautla Natural Reserve, Mexico. METHODS: Allozyme electrophoresis of sixteen loci (eleven polymorphic and five monomorphic) were used. The data were analysed with standard statistical approximations for obtaining diversity, genetic structure and gene flow. KEY RESULTS: Genetic diversity and allelic richness were: HE = 0.21 +/- 0.02, A = 1.86 +/- 0.08, respectively. F-statistics revealed a deficiency of heterozygous plants in all populations (Fit = 0.65 +/- 0.02 and Fis = 0.43 +/- 0.06). Significant genetic differentiation between populations was detected (Fst = 0.39 +/- 0.07). Average gene flow between pairs of populations was relatively low and had high variation (Nm = 0.46 +/- 0.21), which denotes a pattern of isolation by distance. The genetic structure of populations of T. achyrostachys suggests that habitat fragmentation has reduced allelic richness and genetic diversity, and increased significant genetic differentiation (by approx. 40 %) between populations. CONCLUSIONS: The F-statistic values (>0) and the level of gene flow found suggest that habitat fragmentation has broken up the former population structure. In this context, it is proposed that the host trees of T. achyrostachys should be considered as a conservation priority, since they represent the limiting factor to bromeliad population growth and connectivity.     

Spatial and temporal distribution of tadpole assemblages (Amphibia,Anura) in a seasonal dry tropical forest of southeastern Brazil

We determined spatial and temporal distribution of tadpoles in 11 breeding habitats from Morro do Diabo State Park (MDSP), southeastern Brazil. Breeding habitats occupancy by tadpoles was tested to be different from a null model of random placement of species. We also tested whether tadpole occupancy in a given breeding habitat is organized according to different ecomorphological guilds, and we analyzed spatial partitioning of tadpoles among breeding habitats through similarity analysis. For temporal analysis we analyzed temporal partitioning of tadpole monthly occurrence also using similarity analysis, and assessed what climatic variable better predicts tadpole temporal occurrence in the MDSP, through regression analysis. Among tadpoles from 19 anuran species, distribution was different from a null model, but co-occurrence patterns among the breeding habitats did not differ among different guilds. However, breeding habitats with similar hydroperiods had similar species composition, which may be related to the reproduction patterns of species. Among the three climatic variables analyzed (rainfall, temperature, and photoperiod), temporal occurrence of monthly tadpole richness and abundance was correlated with temperature and rainfall. Most species were found only during the rainy season months, and overlap occurred within three groups of species. Thus, temporal distribution does not seem to be an important mechanism in species segregation at the MDSP, where the dry season is pronounced. In this case, spatial partitioning tends to be more important for species coexistence.     

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.     

The Atlantic forest in the Volta Velha Reserve: a tropical rain forest site outside the tropics

With its very broad latitudinal extension (from 5° to 30°S), Brazil's Atlantic Rain Forest includes sites that wouldnot be classified as tropical by commonly used climatic classificationsystems. This situation particularly holds for the sites nearthe southern limits of this ecosystem. The goal of this study was to assess forest floristic composition, physiognomic aspects (deciduousspecies, leaf types, leaf area index) and reproductive biology (monoecious/dioeciousspecies, pollination syndromes and dispersal syndromes) of the Atlantic forest in the Volta VelhaReserve, southern Brazil (26°04 S, 48°38 W Gr). The research focuses on theaffinities of this site, which lies outside generally accepted boundaries for tropical forest. Theresults demonstrate that Volta Velha has a typically tropical floristic composition, apparentlymaintained by local climatic conditions. The differences between the characteristics of the VoltaVelha forest and those of other tropical stands are within the range of differences observed amongclassically defined tropical sites.     

Chromosome numbers, meiotic behavior, and pollen viability of species of Vriesea and Aechmea genera (Bromeliaceae) native to Rio Grande do Sul, Brazil

Chromosome number, meiotic behavior, and pollen viability were analyzed in 15 species of two genera, Vriesea and Aechmea, native to Rio Grande do Sul, Brazil. This study is the first cytogenetic analysis of these taxa. The chromosome numbers are all n = 25, consistent with the proposed base number of x = 25 for Bromeliaceae. All examined taxa displayed regular bivalent pairing and chromosome segregation at meiosis. Observed meiotic abnormalities include univalents in metaphase I; missing or extra chromosomes and precocious division of centromeres in metaphase II; laggards in telophase I and anaphase II/telophase II. The high pollen viability (>88%) reflects a regular meiosis.     

Spatial and temporal distribution of blackflies (Diptera: Simuliidae) in the Itatiaia National Park, Brazil

The distribution of the blackfly larval taxocenoses of different altitudes in the Itatiaia National Park (located in the southeast of Rio de Janeiro state, Brazil 44 degrees 34' - 44 degrees 42' W, 22 degrees 16' - 22 degrees 28' S) was investigated on four campaigns, one in each season of 2003. On each campaign 60 samples were collected, using 30 x 30 cm wooden quadrats, distributed at four sites: Taquaral, Véu da Noiva, Três Picos and Brejo da Lapa. The winter and spring campaigns included two additional sampling sites: Alsene and Agulhas Negras. A total of 3578 larvae and 292 pupae were sampled, representative of six species: Simulium clavibranchium Lutz, S. subnigrum Lutz, S. rappae Py-Daniel, S. incrustatum Lutz, S. stellatum Gil-Azevedo, Figueiró & Maia-Herzog and Lutzsimulium pernigrum Lutz 1910. The highest larvae abundance and diversity were reported at the intermediate altitude site, Brejo da Lapa. Principal Components Analysis (PCA) revealed that L. pernigrum, S. stellatum and S. incrustatum were associated with the smaller breeding sites, the first two species being associated with sunny sites, while S. incrustatum occurred in sites with little sunlight.     

A new species of picramnia (Picramniaceae) from the Atlantic coastal forest of southern Bahia, Brazil

A new species ofPicramnia (Picramniaceae) is described, illustrated, and compared to related Amazonian species. The new species,Picramnia coccinea, is known only from three localities in three adjacent municipalities near Ilhéus, Bahia, and constitutes another example of endemism in the southern Bahian flora.     

Ticks (Acari: Ixodidae) parasitizing humans in an Atlantic rainforest reserve of Southeastern Brazil with notes on host suitability

While conducting projects on ticks from deer and on tick ecology in animal trails in an Atlantic rainforest reserve in Southeastern Brazil, researchers of our group were bitten by ticks several times. Some of these episodes were recorded. Three species of adult ticks attached to humans: Amblyomma brasiliense Aragão, Amblyomma incisum Neumann, and Amblyomma ovale Koch. Eight nymphal attachments with engorgement on humans were recorded. From these, six molted to adults of A. incisum, one to an adult of A. brasiliense, and one had an anomalous molting, therefore the adult tick could not be properly identified. Local reactions to tick attachment varied among individual hosts from almost imperceptible to intense. Especially itching, but hyperemia and swelling as well, were prominent features of the reaction. Overall it can be affirmed that human beings can be a physiologically suitable host species for ticks in the Atlantic rainforest and that itching was an important if not the major component of the resistance to tick bite.     

A review of the ticks (Acari, ixodida) of Brazil, their hosts and geographic distribution - 1. The state of Rio Grande do Sul, southern Brazil

A review of the ticks (Acari, Ixodida) of the State of Rio Grande do Sul, southern Brazil, was completed as a step towards a definitive list (currently indicated as 12) of such species, their hosts and distribution. The ticks: Argas miniatus (poultry), Ixodes loricatus (opossums), Amblyomma aureolatum (dogs), A. calcaratum (anteaters), A. cooperi (capybaras), A. nodosum (anteaters), A. tigrinum (dogs) (Neotropical) and Rhipicephalus sanguineus (dogs) (introduced, cosmopolitan, Afrotropical) were confirmed as present, in addition to the predominant, Boophilus microplus (cattle) (introduced, pan-tropical, Oriental). Of the further 18 species thus far reported in the literature as present in the state, but unavailable for examination: only Ornithodoros brasiliensis (humans and their habitations) (Neotropical), Ixodes affinis (deer) (Nearctic/Neotropical) and I. auritulus (birds) (Nearctic/Neotropical/Afrotropical/ Australasian) are considered likely; 13 species would benefit from corroborative local data but the majority appear unlikely; reports of A. maculatum (Nearctic/Neotropical, but circum-Caribbean) are considered erroneous; the validity of A. fuscum is in doubt. The very recent, first known report of the tropical Anocentor nitens (horses)(Nearctic/Neotropical), but still apparent absence of the tropical A. cajennense (catholic) (Nearctic/Neotropical) and the sub-tropical/temperate Ixodes pararicinus (cattle) (Neotropical) in Rio Grande do Sul are important for considerations on their current biogeographical distribution and its dynamics in South America. The state has relatively long established, introduced ("exotic"), Old World tick species (B. microplus, R. sanguineus) that continue to represent significant pests and disease vectors to their traditional, introduced domestic animal hosts, cattle and urban dogs. There are also indigenous, New World ticks (A. miniatus, O. brasiliensis, A. aureolatum, A. nitens), as both long established and possibly newly locally introduced species in the state, that should be considered as potential and emergent pests and pathogen vectors to humans and their more recently acquired, introduced domestic animal hosts; rural poultry, dogs and horses.