The ‘Island Rule’ Acting on Anuran Populations (Bufonidae: Rhinella ornata) of the Southern Hemisphere

Darwin and Wallace, in the mid‐nineteenth century, were the first to document examples of natural selection acting on island dwellers. A century later a pattern of morphological differences among organisms on islands was coined the ‘island rule’, which states that on islands species with small individuals tend toward gigantism and large individuals tend toward dwarfism. Selective pressures such as limited resources and increased intraspecific competition modulate the size of organisms in these environments. Of the several works that have tested vertebrates for adherence to the island rule only two have addressed amphibians. This work is the third record of body size variation of island amphibian populations, and the first for the Southern Hemisphere. The islands investigated were once continuous with mainland, and now are isolated as a result of sea level fluctuations that took place in the Pleistocene and Holocene. This study compared morphometric variation in populations of Rhinella ornata (Bufonidae) occurring on three islands of the Costa Verde to populations on five continental areas in Rio de Janeiro, Brazil. We measured 18 morphometric variables of 177 individuals. There was a shift toward smaller body size (dwarfism) in two of the three island populations studied. We attribute this general pattern to geographic factors, verifying the expression of the island rule in tropical frogs populations (insular dwarfism) operating inversely in relation to those of temperate environments (island gigantism).     

A new species of Heterocotyle Scott, 1904 (Monogenea: Monocotylidae) from the gills of Dasyatis guttata (Dasyatidae) in southwestern Atlantic waters off Rio de Janeiro, Brazil

Heterocotyle sulamericana n. sp. is described from the gills of Dasyatis guttata (Bloch & Schneider) caught off the coast of Brazil near Rio de Janeiro. This species can be distinguished from all other members of Heterocotyle Scott, 1904 by a combination of the morphology of the male copulatory organ, which is a short, slightly curved, sclerotised tube with no accessory piece, and the haptor, which has a single ridge surmounting all septa. This is the first Heterocotyle species to be described from the southwestern Atlantic.     

Metazoan parasites as biological tags for stock discrimination of whitemouth croaker Micropogonias furnieri

Examination of 248 adult specimens of whitemouth croaker Micropogonias furnieri from five localities along the Brazilian coast revealed 8735 parasites belonging to 41 metazoan species. Samples from Ceará to Bahia and Rio de Janeiro to Santa Catarina showed a high level of correct assignation (92 and 87%, respectively) and cross assignation (i.e. almost all specimens misidentified in Ceará were assigned to Bahia and almost all specimens misidentified in Bahia were classified as Ceará), so samples were pooled in the northern and south‐eastern samples, and Rio Grande do Sul was considered a southern area. Eight parasite species were characteristic of the northern localities, five species were found just in the area associated with south‐eastern localities and two species were characteristic of the southern area providing first evidence of stock discreteness. The multivariate discriminant analysis successfully discriminated three groups of localities associated with three stocks of M. furnieri in Brazil: a northern stock associated with Ceará and Bahia, a south‐eastern stock related to Rio de Janeiro and Santa Catarina and a southern stock in the area of Rio Grande do Sul, which could be considered as the northern limit of the stock associated with the Common Fishing Zone of Uruguay and Argentina.     

Nestedness of desert bat assemblages: species composition patterns in insular and terrestrial landscapes

Nested patterns of community composition exist when species at depauperate sites are subsets of those occurring at sites with more species. Nested subset analysis provides a framework for analyzing species occurrences to determine non-random patterns in community composition and potentially identify mechanisms that may shape faunal assemblages. We examined nested subset structure of desert bat assemblages on 20 islands in the southern Gulf of California and at 27 sites along the Baja California peninsula coast, the presumable source pool for the insular faunas. Nested structure was analyzed using a conservative null model that accounts for expected variation in species richness and species incidence across sites (fixed row and column totals). Associations of nestedness and island traits, such as size and isolation, as well as species traits related to mobility, were assessed to determine the potential role of differential extinction and immigration abilities as mechanisms of nestedness. Bat faunas were significantly nested in both the insular and terrestrial landscape and island size was significantly correlated with nested structure, such that species on smaller islands tended to be subsets of species on larger islands, suggesting that differential extinction vulnerabilities may be important in shaping insular bat faunas. The role of species mobility and immigration abilities is less clearly associated with nestedness in this system. Nestedness in the terrestrial landscape is likely due to stochastic processes related to random placement of individuals and this may also influence nested patterns on islands, but additional data on abundances will be necessary to distinguish among these potential mechanisms.     

Diversity of wasps (Hymenoptera: Aculeata: Vespidae) along an altitudinal gradient of Atlantic Forest in Itatiaia National Park,Brazil

Surveying the diversity of stinging wasps (Hymenoptera: Aculeata) provides an important information base to assist in biodiversity conservation and the management of forest reserves, as wasps depend on and maintain the population balance of several other groups of insects. In accordance, this paper presents an altitudinal survey of wasps (Hymenoptera, Aculeata, Vespidae) in Itatiaia National Park, Brazil, which is a protected area covered by Atlantic Forest in a mountainous landscape, with altitudes ranging between 540 and 2791 metres above sea level. Six altitudinal zones were sampled with entomological net, and the abundance and diversity of the species were indicated by zones. Field sampling took 288 h of discontinuous activity, which was randomly conducted from December 2012 to December 2013. A total of 398 individuals belonging to 29 species and two subfamilies (Eumeninae and Polistinae) were sampled. Eight species are new records for the state of Rio de Janeiro. We found a monotonic decrease in wasp diversity in relation to altitude, and the number of captured individuals differed significantly between the low and high altitudes.     

Island biogeography of bats in Baja California, Mexico: patterns of bat species richness in a near-shore archipelago

Aim We studied the relationship between the size and isolation of islands and bat species richness in a near‐shore archipelago to determine whether communities of vagile mammals conform to predictions of island biogeography theory. We compared patterns of species richness in two subarchipelagos to determine whether area per se or differences in habitat diversity explain variations in bat species richness. Location Islands in the Gulf of California and adjacent coastal habitats on the Baja California peninsula in northwest Mexico. Methods Presence–absence surveys for bats were conducted on 32 islands in the Gulf of California using acoustic and mist‐net surveys. We sampled for bats in coastal habitats of four regions of the Baja peninsula to characterize the source pool of potential colonizing species. We fitted a semi‐log model of species richness and multiple linear regression and used Akaike information criterion model selection to assess the possible influence of log₁₀ area, isolation, and island group (two subarchipelagos) on the species richness of bats. We compared the species richness of bats on islands with greater vegetation densities in the southern gulf (n = 20) with that on drier islands with less vegetation in the northern gulf (n = 12) to investigate the relationship between habitat diversity and the species richness of bats. Results Twelve species of bats were detected on islands in the Gulf of California, and 15 species were detected in coastal habitats on the Baja peninsula. Bat species richness was related to both area and isolation of islands, and was higher in the southern subarchipelago, which has denser vegetation. Log₁₀ area was positively related to bat species richness, which increased by one species for every 5.4‐fold increase in island area. On average, richness declined by one species per 6.25 km increase in isolation from the Baja peninsula. Main conclusions Our results demonstrate that patterns of bat species richness in a near‐shore archipelago are consistent with patterns predicted by the equilibrium theory of island biogeography. Despite their vagility, bats may be more sensitive to moderate levels of isolation than previously expected in near‐shore archipelagos. Differences in vegetation and habitat xericity appear to be associated with richness of bat communities in this desert ecosystem. Although observed patterns of species richness were consistent with those predicted by the equilibrium theory, similar relationships between species richness and size and isolation of islands may arise from patch‐use decision making by individuals (optimal foraging strategies).     

mtDNA ancestry of Rio de Janeiro population,Brazil

Polymorphism studies concerning HVI and HVII regions of mitochondrial DNA (mtDNA) have improved the understanding of the admixture genetic process related to the occupation of the continents by human population groups. We have analyzed the mtDNA lineages of 190 healthy and maternally unrelated individuals born in the metropolitan region of the Rio de Janeiro city, the capital of the State of Rio de Janeiro, southeastern Brazil. The data showing that 57.9, 25.3 and 16.8 % of the matrilineages found in Rio de Janeiro come from African, Amerindian and European population groups. They are, respectively, in close agreement with historical records which indicate that the admixture population of Brazil is the resulting of interethnic asymmetry crosses between individuals from those population groups. The high proportion of African mtDNA lineages in the population of Rio de Janeiro is in accordance with studies related to other Brazilian states.     

Ethnobotany of Atlantic Forest Coastal Communities: II. Diversity of Plant Uses at Sepetiba Bay (SE Brazil)

This is an ethnobotanical study of Atlantic Forest coastal communities located at Sepetiba Bay, Rio de Janeiro State, Brazil. Atlantic Forest remnants are top priority conservation areas, and include native communities that depend on fish and small-scale agriculture. We conducted fieldwork in the community of Calhaus (Jaguanum Island) from 1989 to 1991, and interviewed adults on their use of plants. We examined the diversity of medicinal plants used among communities of different islands and found results similar to previous research at Gamboa (Itacuruçá Island); communities living in smaller islands and on islands further from the coast use a lower diversity of plants. Also, older islanders show a deeper knowledge of medicinal plants than younger islanders.     

A method for testing the host specificity of ectoparasites: give them the opportunity to choose

Host-choice experiments were carried out with rodent and bat ectoparasites on Ilha Grande, state of Rio de Janeiro, Brazil. We constructed experimental chambers that enclosed three different rodent or bat host species, and then introduced a selected set of ectoparasitic arthropods. When given the opportunity to choose among host species, the ectoparasites showed a strong tendency to select their primary hosts, and reject novel host species. These kinds of simple experiments can be valuable tools for assessing the ability of ectoparasites to locate and discern differences between host species, and make choices about which hosts to infest, and which hosts to avoid.     

Medicinal Plants in the Atlantic Forest (Brazil): Knowledge, Use, and Conservation

This study focuses on knowledge of medicinal plants among the Caiçaras (rural inhabitants of the Atlantic Forest coast, Brazil). In particular, we examine the use of medicinal plants according to sex and age to reveal general patterns of Caiçara knowledge and use of plant resources. Data collected through 449 interviews at 12 Caiçara communities (Rio de Janeiro and São Paulo coastal sites) include citations of 249 plants and identification of 227 species. We show the importance of introduced as opposed to native plants and of key individuals for the conservation of the Caiçaras-Atlantic Forest.     

Helminths of the horned leaf frog, Proceratophrys appendiculata, from southeastern Brazil

The helminth fauna of the horned leaf frog, Proceratophrys appendiculata (Anura: Leptodactylidae), was studied from 17 adult individuals from an island in Rio de Janeiro state, southeastern Brazil. A total of five nematode species (Aplectana delirae, Cosmocerca brasiliense, Schulzia travassosi, Rhabdias androgyna and Physaloptera sp.) and an unidentified cestode were recovered from the digestive tract, lungs and gall bladder of P. appendiculata and all the nematode species are new host records. Aplectana delirae had the highest values for the prevalence and intensity of infection and can thus be considered a core species in the helminth community of P. appendiculata. Aplectana crossodactyli Baker, 1980 is synonymized with Aplectana delirae (Fabio, 1971). The helminth fauna of P. appendiculata presents characteristics typical of those in amphibians.     

The northernmost record of Bassanago albescens and comments on the occurrence of Rhynchoconger guppyi (Teleostei: Anguilliformes: Congridae) along the Brazilian coast

The northernmost occurrence of Bassanago albescens in the western Atlantic Ocean (off the coast of Rio de Janeiro, Brazil) is presented and compared with the available data on this species. Specimens formerly identified as Rhynchoconger guppyi from off the southern Brazilian coast are regarded as B. albescens.     

Antifouling activity as a function of population variation in <Emphasis Type="Italic">Sargassum vulgare</Emphasis> from the littoral of Rio de Janeiro (Brazil)

The brown seaweed Sargassum vulgare is abundant along the coast of Rio de Janeiro state. An investigation of the spatial variation of antifouling activity was conducted, in which algae were collected at five locations along the coast of Rio de Janeiro during October 2008. Hexane, dichloromethane, methanol and acetone/water extracts were prepared and screened for their bioactivities against the growth of five strains of marine fouling bacteria, five biofilm-associated microphytobenthic strains and attachment of the mussel Perna perna. The most active were the hexane extracts from Bananal algae that inhibited the growth of all microalgae tested; the methanol and dichloromethane extracts from Mar do Norte, which inhibited Vibrio aestuarianus and Pseudoalteromonas elyakovii and the polyphenol extracts from Ilha de Itacuruçá and Bananal that inhibited mussel attachment, respectively, by 64% and 71% compared to controls.     

Spatial and temporal variation of <Emphasis Type="Italic">Hypnea musciformis</Emphasis> carrageenan (Rhodophyta - Gigartinales) from natural beds in Rio de Janeiro State,Brazil

Hypnea musciformis (Wulfen in Jacqu.) J. V. Lamour. is a native source of kappa-carrageenan, a commercially important galactan, exploited for decades on the northeastern Brazilian coast. Further studies to obtain information about the effects of abiotic factors on the carrageenan yield and quality of specimens from the southeastern Brazilian coast (Rio de Janeiro State) are needed. In this study, the carrageenan yield and quality of H. musciformis was analyzed over a period of 1 year in populations from Rio de Janeiro state. One epiphytic population was collected at a site situated at the entrance of the Sepetiba Bay (Praia Vermelha), another in the middle of the bay (Praia Grande) and a third (Praia Rasa) in a place exposed to the open sea. An epilithic population was also collected at Praia Rasa. In the sampling period, different changes were observed in the carrageenan yield and quality (viscosity and sulphate content) of the H. musciformis (August 1994 to June 1995) at the different sites and habitats (epilithic and epiphytic). Kappa carrageenan was the only one of its type detected. Only one population showed a correlation between viscosity and degree of sulphate content. Our analyses suggest that abiotic factors, such as water movement, desiccation stress, low salinity and extreme temperatures, were the main abiotic factors that influenced the changes in carrageenan of the populations studied. Thus, for a rational use of natural beds of H. musciformis, it is desirable to estimate the changes in carrageenan and algal biomass in the place to be exploited.     

Phytogeography of the liverwort flora of the Atlantic Forest of southeastern Brazil

Abstract

This work analyzes the phytogeographic patterns of the liverwort flora of the Atlantic Forest of the Rio de Janeiro State, south-eastern Brazil. The analysis was based on inventories made in fragments of Atlantic Forest in the state, collections from the RB herbarium, and information from the checklist and database of the bryoflora of Rio de Janeiro. The phytogeographic pattern for each taxon was characterized based on its current distribution. Three hundred and sixty liverwort taxa are recognized for Rio de Janeiro. The liverwort flora varies along an altitudinal gradient within the Atlantic Forest, with the montane belt having the greatest species richness (238), the highest number of exclusive taxa (63) and the greatest number of endemic species (23). The predominant phytogeographic element is of neotropical species (49%), followed by disjunct liverworts (18%). Forty-one taxa (11%) are endemic to the country, of which 34 are restricted to the Atlantic Forest. In the lowland and submontane formations species are wide-ranging, whereas the montane and upper montane formations are characterized by endemic species or those disjunct with the Andes. The liverwort flora emphasizes the importance of the fragments of Atlantic Forest in Rio de Janeiro as a centre of diversity and endemism, supporting 50% of the total liverwort species known in Brazil, 72% of those recorded from Atlantic Forest and 55% of the endemic species of the country. Species with an Afro-American and Andean disjunction make up a characteristic part of the liverwort flora, probably reflecting the effects of long-distance dispersal by air currents, migration over land before the breakup of the continents and climatic similarities between the high-altitude grasslands and the northern Andes.     

Further description of Procamallanus (Spirocamallanus) halitrophus comb. n. (Nematoda: Camallanidae) from flounder off the Brazilian coast by light and scanning electron microscopy

Procamallanus (Spirocamallanus) halitrophus Fusco and Overstreet, 1978 from the intestines of flounders (Syacium papillosum and Citharichthys macrops) from the coast of the State of Rio de Janeiro, Brazil, is redescribed. This study, which is based on results obtained by light and scanning electron microscopy, clarifies many morphological aspects of this species. Some taxonomic features, such as the cephalic structures, the topography of the cuticle, the vulva, the localization of caudal papillae on males, and the excretory pore, are observed for the first time. C. macrops represents a new host record, and Rio de Janeiro is a new geographical record for this species.     

Assemblage-level responses of phyllostomid bats to tropical forest fragmentation: land-bridge islands as a model system

Aim Working within a system of high structural contrast between fragments and the surrounding matrix, we assessed patterns of species loss and changes in species composition of phyllostomid bats on artificial land‐bridge islands relative to mainland assemblages, and evaluated the responses of bats to forest edges. We further examined the relative influence of local‐scale characteristics (e.g. vegetation structure, island area) versus landscape attributes (e.g. forest cover, patch density) and the importance of spatial scale in determining phyllostomid species richness and composition on islands. Location Islands in Gatún Lake and adjacent mainland peninsulas in the Barro Colorado Nature Monument, Panama. Methods Bats were sampled over a 2‐year period on 11 islands as well as at forest‐edge and interior sites on adjacent mainland, resulting in > 8400 captures. Results The islands harboured a less diverse and structurally simplified phyllostomid bat fauna. Islands far from the mainland were especially species‐poor. This decline in species richness was associated with compositional shifts towards assemblages strongly dominated by frugivores with good dispersal abilities. Members of other ensembles, most importantly gleaning animalivores, were much less common or absent. Although overall species composition was not significantly altered, species richness at continuous forest‐edge sites was significantly lower compared with that at interior sites. Distance from the mainland and amount of forest cover in the landscape were the best predictors of species richness and assemblage composition. Responses were scale‐dependent. At the local scale, species richness was independent of island area but was correlated positively with distance from the mainland. In contrast, area effects became more important at larger spatial scales, suggesting that many species use multiple fragments. Main conclusions Our results underline the conservation value of small habitat remnants, which, even when embedded in a hostile matrix, can support a relatively diverse bat fauna, provided that there is a low degree of patch isolation and spatial proximity to larger tracts of continuous forest. Although the results at the assemblage level were inconclusive, we demonstrate that certain bat species and ensembles, particularly gleaning animalivores, exhibit high edge‐sensitivity. Our results point to habitat loss rather than changes in landscape configuration as the main process after isolation underlying phyllostomid bat responses, suggesting that conservation efforts should focus on habitat preservation instead of trying to minimize fragmentation per se at the expense of habitat amount.     

Alphacoronaviruses in New World bats: prevalence, persistence, phylogeny, and potential for interaction with humans

Bats are reservoirs for many different coronaviruses (CoVs) as well as many other important zoonotic viruses. We sampled feces and/or anal swabs of 1,044 insectivorous bats of 2 families and 17 species from 21 different locations within Colorado from 2007 to 2009. We detected alphacoronavirus RNA in bats of 4 species: big brown bats (Eptesicus fuscus), 10% prevalence; long-legged bats (Myotis volans), 8% prevalence; little brown bats (Myotis lucifugus), 3% prevalence; and western long-eared bats (Myotis evotis), 2% prevalence. Overall, juvenile bats were twice as likely to be positive for CoV RNA as adult bats. At two of the rural sampling sites, CoV RNAs were detected in big brown and long-legged bats during the three sequential summers of this study. CoV RNA was detected in big brown bats in all five of the urban maternity roosts sampled throughout each of the periods tested. Individually tagged big brown bats that were positive for CoV RNA and later sampled again all became CoV RNA negative. Nucleotide sequences in the RdRp gene fell into 3 main clusters, all distinct from those of Old World bats. Similar nucleotide sequences were found in amplicons from gene 1b and the spike gene in both a big-brown and a long-legged bat, indicating that a CoV may be capable of infecting bats of different genera. These data suggest that ongoing evolution of CoVs in bats creates the possibility of a continued threat for emergence into hosts of other species. Alphacoronavirus RNA was detected at a high prevalence in big brown bats in roosts in close proximity to human habitations (10%) and known to have direct contact with people (19%), suggesting that significant potential opportunities exist for cross-species transmission of these viruses. Further CoV surveillance studies in bats throughout the Americas are warranted.     

Genetic and morphometric evidence that the jacks (Carangidae) fished off the coast of Rio de Janeiro (Brazil) comprise four different species

Individuals of jacks that were captured off the Rio de Janeiro coast were characterized using multivariate morphometrics and allozymes molecular markers. The main objectives were to determine the number of fish captured and their species. Classical taxonomic classification and multivariate morphometry indicated the existence of three species in the landings from Rio de Janeiro State (Caranx crysos, Carangoides bartholomaei and Caranx latus). The results of the genetic analyses performed were consistent with these results. However, Bayesian analysis revealed the possible presence of a fourth species, which could not be discriminated by classical taxonomy. Caranx crysos possibly comprises two different species. Other population indexes, such as unique alleles, degree of structuring and genetic identity, also pointed to different species. Therefore, based on evidences from classical taxonomy, geometric morphometric analyses together with genetic data from allozymes molecular markers it is possible to support that at least four different Carangidae species are present in fish landings from Niterói, Rio de Janeiro State, Brazil, whereas fish capture records for the same location have recorded only two species. These results are important for not only developing fisheries management strategies but also providing general information regarding the ecology and evolution of the genus.     

Island biogeography extends to small-scale habitats: low competitor density and richness on islands may drive trait variation in nonnative plants

Previous island biogeography studies have quantified species richness on the scale of entire islands rather than smaller scales relevant to plant-to-plant competitive interactions. Further, they have not accounted for density compensation. Using mainland and island sites along the New England coast, we asked two questions. First, are both richness and density lower in small-scale habitats within islands than in similar mainland habitats? Second, do differences in competitor richness and density drive post-establishment trait variation in nonnative plant species? We used field surveys and individual-based rarefaction to estimate richness and density in 100-m² plots and demonstrated that island sites have significantly fewer species and individuals per unit area than mainland sites. We then conducted a field study in which we removed competing neighbors from nonnative plant individuals and found that when competitors were removed, individuals in low-competition environments demonstrated a lesser increase in vegetative growth but a greater increase in reproductive effort and herbivore tolerance relative to mainland individuals whose neighbors were also removed. We found that the central concept of island biogeography, i.e., that islands host fewer species than comparable mainland habitats, can be extended to smaller-scale habitats and that this difference in competitive pressure between mainland and island habitats can act as a driver of trait variation in nonnative plants.