Rainforest In Southeastern Brazil Research Articles

Population structure and demographic inferences concerning the endangered onychophoran species Epiperipatus acacioi (Onychophora: Peripatidae)

Epiperipatus acacioi (Onychophora: Peripatidae) is an endemic species of the Atlantic rainforest in southeastern Brazil, with a restricted known distribution, found only in two nearby areas (Tripuí and Itacolomi). Mitochondrial gene COI sequences of 93 specimens collected across the known range of E. acacioi were used to assess the extant genetic diversity and patterns of genetic structure, as well as to infer the demographic history of this species. We found considerable variability within the populations, even though there has been recent environmental disturbance in these habitats. The samples from the two areas where this species is found showed significantly different COI sequences and constitute two distinct populations [exact test of sample differentiation (P = 0.0008) and pairwise F(ST) analyses (F(ST) = 0.214, P < 0.00001)]. However, there was little genetic differentiation among samples from different sampling sites within populations, suggesting that the potential for dispersal of E. acacioi greater than would have been expected, based on their cryptic behavior and reduced vagility. Mismatch analyses and neutrality tests revealed evidence of recent population expansion processes for both populations, possibly related to variations in the past distribution of this species.

Tipos polínicos encontrados em esfingídeos (Lepidoptera, Sphingidae) em área de Floresta Atlântica do sudeste do Brasil: uso da palinologia no estudo de interações ecológicas

(Tipos polinicos encontrados em esfingideos (Lepidoptera, Sphingidae) em area de Floresta Atlântica do Sudeste do Brasil: uso da palinologia no estudo de interacoes ecologicas). Foram determinadas as especies de plantas utilizadas por uma comunidade de esfingideos (Lepidoptera, Sphingidae) atraves da avaliacao dos tipos polinicos que os especimes apresentavam sobre seus corpos, em uma area de Floresta Atlântica do Sudeste do Brasil. Foram registrados 63 tipos polinicos de 27 familias distribuidos assimetricamente ao longo do ano. Houve predominio de especies de Rubiaceae, Bromeliaceae e Fabaceae. Polen do tipo Inga esteve presente em quase todos os meses amostrados e em grande numero de especies de esfingideos. Tipos polinicos relativos a familias que nao apresentam atributos morfologicos adaptativos ao uso por Sphingidae foram responsaveis pela maior parte das amostras, o que demonstra forte aspecto generalista no comportamento de forrageamento deste grupo de lepidopteros. Este estudo reforca a utilidade do uso da palinologia no entendimento de padroes de interacoes inseto-planta em ambientes tropicais.

Attendance and Co-Occurrence of Birds Following Army Ants in the Atlantic Rain Forest

In a first attempt to formally test competitive interactions among army-ant-following birds, we explored the patterns of occurrence of birds following swarms of army ants in the Atlantic rain forest of southeastern Brazil. We contrasted the frequency of occurrence of birds at ant swarms at a lowland and a highland site. Additionally, we assessed the patterns of co-occurrence of bird species at ant swarms, using null models to test for the possibility of competitive exclusion. Despite the larger number of attending bird species at the highland site, we detected no differences between the sites in either the frequency of attendance or the number of bird species per swarm. Analyses of co-occurrence did not reveal evidence of negative association of bird species attending ant swarms at the lowland site but did at the more species-rich highland site. Pairwise analyses showed that this negative association invariably involved two of the species attending ant swarms most frequently, Pyriglena leucoptera and Trichothraupis melanops, suggesting a competitive interaction. Possibly, although birds that are more dependent upon army ants avoid competitive exclusion by spatial segregation at the swarm's front, birds that follow army ants less frequently are occasionally excluded from the swarms.

Composition of Leaf and Rhizome Essential Oils of Hedychium coronarium Koen. from Brazil

Hydrodistillation of fresh leaves and rhizomes of Hedychium coronarium collected in the Atlantic rain forest of southeastern Brazil afforded essential oils in 0.68% and 0.20% yields, respectively. Analysis of the oils by GC and GC/MS revealed as predominant constituents in the leaf oil β-caryophyllene (43.0%), caryophyllene oxide (12.1%) and β-pinene (11.6%,), whereas 1,8-cineole (34.8%), β-pinene (16.7%) and α-terpineol (13.1%) were the major components identified in the rhizome oil.

Flower mites decrease nectar availability in the rain-forest bromeliad Neoregelia johannis

Abstract:Nectarivorous flower mites can reduce the volume of nectar available to pollinators. The effects of the flower mite Proctolaelaps sp. on nectar availability in flowers of a melittophilous bromeliad Neoregelia johannis (Bromeliaceae) was evaluated in a coastal rain forest in south-eastern Brazil. In a randomized block experiment utilizing 18 flower pairs, one per bromeliad ramet, pollinators (Bombus morio) and mites were excluded, and then nectar volume, sugar concentration and sugar mass were quantified over the anthesis period. Mites significantly reduced nectar volume early in the morning (6h00–8h00), but not later (10h00–12h00). Mites decreased total volume of nectar available up to 22%. Sugar concentration in nectar was higher earlier in the morning, and decreased between 10h00–12h00. The pronounced consumption of nectar by mites during the period of higher sugar concentration reduced the total amount of sugar available to pollinators by 31%. This is the first study showing that flower mites decrease nectar rewards in a melittophilous plant. Because nectar volume by itself incompletely describes nectar production rates and the effects of nectar removal by flower mites on the availability of sugar, our study highlights the inclusion of sugar content in future studies assessing the effects of thieves on nectar production rates.

Cyathea atrocastanea a New Tree Fern from the Atlantic Rain Forest of Southeastern Brazil

Cyathea atrocastanea, a new species of tree fern is described, illustrated, and compared with similar species. This new species should be classified as vulnerable (VU) according to the IUCN criteria. This species is distinct by its atrocastaneous and scurfy petiole, and rachis, and by the broad ovate and yellowish, nonbullate scales on the costulae and midveins. A key to the exindusiate species from southeastern Brazil with nondenticulate petiole scales is also presented.

13C NMR and FTIR spectroscopy characterization of humic acids in spodosols under tropical rain forest in southeastern Brazil

The aim of the present study was to characterize the humic acids (HAs) in spodosols developed on quartzitic, sandy, nutrient-poor parent materials under restinga forest. 13C NMR and FTIR spectroscopy were used to obtain information about the mechanism of podzolization in tropical climates in three sandy coastal podzols (Histic Alaquod, Typic Alorthod and Arenic Alorthod) from Cardoso Island (Sao Paulo-Brazil). HAs were extracted from all horizons and 13C NMR and FTIR measurements were performed on all HA samples. Similarities between the surface horizon A from a Typic Alorthod (C14) and the Ho horizon from a Histic Alaquod (H13) were observed. Below the E horizon, the spectra of profile H13 closely resembled the spectra of C14. The increase in alkyl carbon and decrease in acetal carbon, aromatic C and phenolic C with increasing depth suggests enrichment of methylene structures by the microbial biomass. This idea was further supported by an increase in the decomposition of polysaccharides and lignin throughout the profiles. The similarity of the composition may be evidence of vertical translocation throughout the profile, with no incorporation of organic matter (OM) components from other sources such as roots or their residues. The chemical structure of profile Arenic Alorthod (H9) differed from that of the other profiles. The increase in methoxylic, aromatic and phenolic groups as depth increased probably indicates an increase in tannin-like compounds with depth. The higher content of tannins in this soil indicates the presence of more fresh litter and/or a less intense decomposition process than in Histic Alaquod and Typic Alorthod soils. In the latter soil the large amounts of aliphatics and small amounts of lignin-derived products reflect strong aerobic decay. The presence of significant methylene absorption in the FTIR spectra indicates that this alkyl material was dominated by the mobile lignin-derived products, in accordance with the NMR results, which revealed that the HAs have greater aliphatic than aromatic character.

An apparent lack of prezygotic reproductive isolation among 42 sympatric species of Bromeliaceae in southeastern Brazil

The Atlantic rainforest in southeastern Brazil is one the main centers of diversification of Bromeliaceae. Empirical estimates of the relative importance of different pre- and postzygotic barriers to gene flow between recently diverged species are important for understanding speciation processes. While many bromeliad species easily hybridize in cultivation, few records of natural hybrids between closely related sympatric species suggest the existence of strong prezygotic barriers. A community of 42 sympatric bromeliad species, represented by nine genera (Aechmea, Billbergia, Edmundoa, Neoregelia, Nidularium, Quesnelia, Racinaea, Tillandsia, and Vriesea), were surveyed from 2004–2005 to assess the role of microhabitat isolation, phenological isolation and ethological isolation as potential prezygotic barriers. These bromeliads are abundant in the understory and frequently grow densely aggregated in multispecific patches that may facilitate promiscuous pollination. There was a large overlap of flowering periods even between congeneric species. Most species shared a similar assemblage of flower visitors; the hummingbird Rhamphodon naevius was the major visitor for 35 species. Only one putative hybrid was observed. This uncommonness of hybridization is puzzling, given that the prezygotic isolation mechanisms investigated are potentially weak to effectively avoid interspecific pollination.

Ornithophilous canopy species in the Atlantic rain forest of southeastern Brazil

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Reproductive biology of two tree species of Leguminosae in a Montane Rain Forest in southeastern Brazil

Studies on sympatric species that belong to the same taxonomic group and have the same pattern of pollination and seed dispersion, but different patterns of geographical distribution and structural parameters may be worthwhile to understand the evolution of their compatibility system. We studied the floral biology, pollinators and reproductive systems of two tree species in Itatiaia, an area covered with montane rain forest. Pseudopiptadenia contorta is widespread in Brazil but is present at a low relative density at the study site, while Pseudopiptadenia leptostachya is restrictively distributed but presents one of its highest relative density values in Itatiaia. Both species have small flowers arranged in compact spicate raceme inflorescences that constitute the pollination unit. Pollinators are native stingless bees and European honeybees that collect pollen from their nectarless flowers. Although both species have similar floral characteristics and pollination system, their compatibility system differs. Fruit set after manual pollinations and observation of the pollen tube growth showed that P. leptostachya is self-compatible while P. contorta only set fruits after cross-pollinations, and is thus a self-incompatible species. However, fruit set did not differ between the species, indicating that structural parameters are not affected by the compatibility system. Thus, the difference between these two species in terms of reproductive system may be related to other factors such as patterns of geographical distribution.

Facultative autogamy in Cyrtopodium polyphyllum (Orchidaceae) through a rain-assisted pollination mechanism

Cyrtopodium includes ~42 species, among which is Cyrtopodium polyphyllum (Vell.) Pabst ex F. Barros that occurs in a rainforest in south-eastern Brazil. Its non-rewarding flowers, which attract Centridini bees by deceit, are rain-assisted self-pollinated, a phenomenon rarely found in orchids and other plant families. In addition, self-pollination has never been reported in Cyrtopodiinae and data on the pollination of South American orchids are scarce. Flowers were observed at different times of the day, on both sunny and rainy days, to record floral morphology, visitors and the effects of rainfall on flowers. On rainy days, water accumulates on the stigma and dissolves the adhesive substance of the stigmatic surface. A viscous drop thus forms, which contacts the pollinarium. When evaporation makes the viscous drop shrink, the drop moves the pollinarium with the anther onto the stigmatic surface and promotes self-pollination. Fruit set in natural habitat was low, with 2.4% at one study site, where a similar value (2.2%) was recorded in flowers self-pollinated by rain. In C. polyphyllum, facultative self-pollination assisted by rain is thus an important strategy that guarantees fruit set when pollinator’s visits are scarce, which is common in species pollinated by deceit.

Floral biology and breeding system of Psychotria tenuinervis Muell. Arg. (Rubiaceae) in the Atlantic rain forest, SE Brazil

(Floral biology and breeding system oi Psychotria tenuinervis Muell. Arg. (Rubiaceae) in the Atlantic rain forest, SE Brazil). The aim of this study was to investigate pollination biology, floral morphometry, morph ratio and breeding system oiPsychotria tenuinervis in an area of Atlantic rain forest in southeastern Brazil. Pollination biology was studied based on focal observations and the breeding system was determined using controlled crosses; data on flower production and floral morphometry were compared between the two floral morphs. Flower production by the two floral morphs was similar, with flowers being reciprocally herkogamous, diurnal and pollinated at similar frequencies, mainly by medium-sized bees. Corolla length and diameter, as well as anther length, were similar between the floral morphs, whereas stigma lobes were larger in thrums. Psychotria tenuinervis is a preferentially self- and intramorph-incompatible, non-apomitic species, with isoplethic populations. At the study site, P. tenuinervis may be considered as a typical distylous species, with reciprocal herkogamous flowers that favour intermorph pollinations and legitimate matings.

Gap disturbance regime and composition in the Atlantic Montane Rain Forest: the influence of topography

In the Atlantic Montane Rain Forest of south-eastern Brazil, a field study was carried out to describe the forest disturbance regime, analyse canopy gap composition and evaluate the influence of habitat parameters on gap tree species composition. We characterized canopy gaps considering the group of variables as follows: area, type and number of tree/branch falls, topographic position, soil coverage and surrounding canopy trees. Gap composition was assessed at species level by measuring all individuals inside gaps higher than one meter. Mean gap area of the 42 canopy gaps analysed was 71.9 ± 9.0 m² (mean ± SE). Out of the studied gaps, 35.7% were created by uprooted and by snapped trees, 16.7% by dead-standing trees and 11.9% by the fall of large branches. The disturbance regime was characterized by gap openings predominantly smaller than 150 m² and by spatial patterning related to topography. Ridges had smaller gaps and higher proportions of gaps created by branch falls; slopes had bigger gaps generally created by uprooting events. The more abundant and frequent species were shade tolerant and the more species-rich families found inside gaps did not differ from the forest as a whole. Pioneer species were rare and restricted to medium and large size classes. The Indicator Species Analysis and the Canonical Correspondence Analysis indicated gap area, topography and the percentage of soil cover by the genera Calathea and Ctenanthe were the predominant variables correlated with woody species distribution. So, topography emerged as an important issue not only to the gap disturbance regime, but also to gap colonization. In respect to the influence of gap processes on the Atlantic Montane Rain Forest regeneration, our results support the view that canopy gap events may not be working as promoters of community wide floristic shifts.

Ant communities (Hymenoptera: Formicidae) in an urban ecosystem near the Atlantic Rainforest

The relationships between an urban ecosystem located near the Atlantic Rainforest in southeastern Brazil and ant communities were studied with the objective of quantifying the ant richness and abundance in the household environment and its surroundings. Eighty residences were sampled, where 58 species and 28 genera pertaining to 7 sub-families were found to be present. Inside the residences, the species richness was found to be lower (26), although the abundance was greater (10,670), with the wash area and kitchen being the locales that contributed with the greatest number of hits. The opposite was true in the areas outside the residences, where 54 species and 3,747 ants were observed. Inside houses, the species known as Tramp ants were found, in the following order of importance: Solenopsis saevissima, Tapinoma melanocephalum, Linepithema humile, Paratrechina fulva, Wasmannia auropunctata, P. longicornis, Pheidole megacephala, Monomorium pharaonis and M. floricola. Externally, mainly in the yards and gardens, species such as Octostruma rugifera, Heteroponera dolo, Hypoponera sp.1 and sp.6, Gnamptogenys sp. 4, G. striatula, Odontomachus meinerti, Pachycondyla constricta and P. striata were found. In general, a greater number of species and lower abundance of individuals were observed in the neighborhoods nearer the mountains than in those closer to the urban center.

Composição e diversidade de anfíbios anuros em dois ambientes de Mata Atlântica no Parque Estadual Carlos Botelho, São Paulo, sudeste do Brasil

A Mata Atlântica é caracterizada pela elevada riqueza e endemismo de espécies, e é um dos 25 hotspots de biodiversidade mundiais. Apresentamos informações sobre a composição e diversidade de espécies de anfíbios anuros em dois ambientes com diferentes graus de perturbação no Parque Estadual Carlos Botelho, SP, uma área de Mata Atlântica no sudeste do Brasil. Amostramos um açude em área alterada e uma lagoa em área preservada, através de procura auditiva e encontros ocasionais em 36 noites de observação em cada ambiente. As duas áreas foram comparadas em relação à composição, riqueza, dominância e abundância relativa de espécies. Apesar de próximos, cerca de 400 m, apenas duas espécies foram comuns aos dois ambientes. Na área alterada registramos 10 espécies (N = 518) e dominância de 46,7% de Hypsiboas albopunctatus, e na área preservada 11 espécies (N = 656) e dominância de 36,0% de Dendropsophus giesleri. A riqueza não foi significativamente diferente nos dois ambientes. A dominância estimada por rarefação na área preservada foi significativamente menor em relação à observada na área alterada. A capacidade das populações de algumas espécies em colonizar a área alterada, tolerâncias fisiológicas distintas entre as espécies e a dependência de microambientes específicos para a reprodução são possíveis fatores responsáveis pelos padrões observados. Sugerimos que alterações adicionais da cobertura original de Mata Atlântica na reserva poderão resultar em um decréscimo na diversidade alfa, devido a eliminação de espécies ecologicamente dependentes de ambientes florestais, e um conseqüente aumento na diversidade beta, resultante da colonização de espécies de área alterada ecologicamente mais generalistas. A riqueza ligeiramente maior e principalmente a menor dominância observada na área preservada indicam ser esta uma área que apresenta maior diversidade de espécies. Assim, a presença de florestas pouco perturbadas e/ou conservadas na reserva é fundamental para a manutenção da diversidade da anurofauna local.

Canopy gap colonization in the Atlantic Montane Rain Forest

In the Atlantic Montane Rain Forest of South-eastern Brazil, a study was carried out to describe and evaluate canopy gap colonization. Gap composition by herb species was assessed through their soil coverage and woody species by measuring and identifying all individuals taller than one meter. Gap structure (gap size, number and diameter of treefalls), topographic position and surrounding vegetation were also measured. Two genera of Marantaceae were markedly frequent and abundant inside gaps. The more abundant and frequent woody species were shade tolerant. Species-rich families found inside gaps did not differ from the forest as a whole. Results revealed that direct and indirect influences of topography were important to determine gap composition of woody species. Evidently gap colonization had a considerable influence of topography and pre-established individuals besides variables of gap structure.

Edge effects on the orchid-bee fauna (Hymenoptera: Apidae) at a large remnant of Atlantic Rain Forest in southeastern Brazil

Male orchid bees were sampled with chemical baits monthly from July 1999 to April 2000 at six sites situated at different distances from the forest edge (0 to 4,000 m) at Parque Estadual do Rio Doce, the largest remnant of Atlantic Forest in the state of Minas Gerais, southeastern Brazil. The main goal of this study was to assess the abundance, richness, and the community structure of the orchid-bee fauna at different distances from the edge. In all, 1,183 males from 20 species were collected. Only minor and insignificant variation in richness and abundance were observed among the sites. Two dominant species, Euglossa analis Westwood (Hymenoptera: Apidae) and Eulaema cingulata (Fabricius) (Hymenoptera: Apidae), showed strongly opposing habitat associations: while males of the former were most collected in the interior of the forest, the latter was most found at or close to the edge. The responses of individual species, such as these, and not composite measures of richness and abundance, are more informative regarding forest integrity and edge effects.

Moss diversity in the tropical rainforests of Rio de Janeiro, southeastern Brazil

Moss diversity at various sites in the Tropical Atlantic Rainforest of southeastern Brazil is high, with 338 taxa distributed among 49 families and 129 genera. Comparisons of species richness in the Tropical Atlantic Rainforest in southeastern Brazil suggest that the moss flora is not uniform, and that lowland, montane, submontane, and upper montane Atlantic rainforests have very different moss floras. Montane Atlantic Rainforest has the largest number of exclusive species and the highest species richness, Sub-Montane Atlantic Rainforest has intermediate species richness, while the Lowland Atlantic Rainforest has fewer species. The high diversity of the Montane Atlantic Rainforest could be explained by the diversity of climatic, edaphic, and physiographic changes of the vegetation. Sematophyllaceae accounted for 19% of the taxa in lowland forest, Meteoriaceae for 10% of the taxa in montane forests, and Dicranaceae for 18% of the taxa in upper montane forests. Taxa with broad Neotropical distributions (40% of the total taxa) are important elements in all the forests, while taxa restricted to Brazil comprise the second most important element in upper montane and montane forests.

Distyly and variation in floral traits in natural populations of Psychotria ipecacuanha (Brot.) Stokes (Rubiaceae)

Psychotria ipecacuanha is a perennial, medicinal herb that grows in clusters in the understory of humid, shady areas of the Atlantic Rain Forest of southeastern Brazil. The present study characterized the variation in floral traits among 35 clusters from three natural populations of this plant species. Field observations showed that the clusters are isomorphic, that is, a given cluster will either set long-styled or short-styled flowers. Stigmas and anthers are reciprocally placed in each morph, a dimorphism characteristic of distyly. The populations are isoplethic, that is, a given population exhibits an equilibrium 1:1 ratio of floral morphs. Morphometric analyses revealed that anther length, stigma length, corolla diameter, and pollen grain diameter were consistently greater in short-styled flowers, regardless of the population investigated. Significant differences for floral traits in the short-styled morph were found among populations. Floral traits in the long-styled morph also showed some significant differences among populations, but not for stigma height and corolla length. Controlled pollinations carried out in natural populations showed that fruit production was higher after inter-morph pollination. Nevertheless, observations of pollen tube growth in style, and also fruit production after spontaneous self-pollination and intra-morph pollination, indicated partial intramorph compatibility in this plant species.

Variation in emetine and cephaeline contents in roots of wild Ipecac ( Psychotria ipecacuanha)

Ipecac ( Psychotria ipecacuanha) is a perennial, medicinal herb that grows as clusters in the understory of humid, shady areas of the Atlantic Rain Forest of southeastern Brazil. This investigation followed the contents of emetine and cephaeline, the bioactive constituents, and assessed root attributes in roots that were sampled periodically from four clusters of Ipecac (VRB8, ITA1, ITA2, and ITA3) that were growing in natural conditions. HPLC analyses showed that the content of the two alkaloids underwent monthly fluctuations over one year period. The concentration of emetine, but not cephaeline, differed significantly among the four clusters. The highest mean content of emetine was found in VRB8 (1.44%), followed by ITA1 (1.14%), ITA2 (0.63%), and finally ITA3 (0.44%). The highest mean content of cephaeline was found in ITA2 and ITA3 (0.26%), although it was not significantly different from ITA1 and VRB8 contents (0.15%). Correlation analysis revealed that contents of emetine are significant ( P < 0.01), but negatively correlated (−0.23) with that of cephaeline. Small sized roots characterized the low-emetine clusters ITA2 and ITA3, while the high-emetine clusters ITA1 and VRB8 consistently yielded larger roots. In these four clusters, emetine contents were correlated positively with fresh root weight, and with diameter and weight of the dried root. Conversely, cephaeline contents were negatively correlated with these three attributes.