Litterfall production in intact and selectively logged forests in southern of Amazonia as a function of basal area of vegetation and plant density

Nutrient recycling in the forest is linked to the production and decomposition of litter, which are essential processes for forest maintenance, especially in regions of nutritionally poor soils. Human interventions in forest such as selecttive logging may have strong impacts on these processes. The objectives of this study were to estimate litterfall production and evaluate the influence of environmental factors (basal area of vegetation, plant density, canopy cover, and soil physicochemical properties) and anthropogenic factors (post-management age and exploited basal area) on this production, in areas of intact and exploited forest in southern Amazonia, located in the northern parts of Mato Grosso state. This study was conducted at five locations and the average annual production of litterfall was 10.6 Mg ha-1 year-1, higher than the values for the Amazon rainforest. There were differences in litterfall productions between study locations. Effects of historical logging intensity on litterfall production were not significant. Effects of basal area of vegetation and tree density on litterfall production were observed, highlighting the importance of local vegetation characteristics in litterfall production. This study demonstrated areas of transition between the Amazonia-Cerrado tend to have a higher litterfall production than Cerrado and Amazonia regions, and this information is important for a better understanding of the dynamics of nutrient and carbon cycling in these transition regions.

Predicting the distribution of forest tree species using topographic variables and vegetation index in eastern Acre, Brazil

Species distribution modeling has relevant implications for the studies of biodiversity, decision making about conservation and knowledge about ecological requirements of the species. The aim of this study was to evaluate if the use of forest inventories can improve the estimation of occurrence probability, identify the limits of the potential distribution and habitat preference of a group of timber tree species. The environmental predictor variables were: elevation, slope, aspect, normalized difference vegetation index (NDVI) and height above the nearest drainage (HAND). To estimate the distribution of species we used the maximum entropy method (Maxent). In comparison with a random distribution, using topographic variables and vegetation index as features, the Maxent method predicted with an average accuracy of 86% the geographical distribution of studied species. The altitude and NDVI were the most important variables. There were limitations to the interpolation of the models for non-sampled locations and that are outside of the elevation gradient associated with the occurrence data in approximately 7% of the basin area. Ceiba pentandra (samaúma), Castilla ulei (caucho) and Hura crepitans (assacu) is more likely to occur in nearby water course areas. Clarisia racemosa (guariúba), Amburana acreana (cerejeira), Aspidosperma macrocarpon (pereiro), Apuleia leiocarpa (cumaru cetim), Aspidosperma parvifolium (amarelão) and Astronium lecointei (aroeira) can also occur in upland forest and well drained soils. This modeling approach has potential for application on other tropical species still less studied, especially those that are under pressure from logging.

Relacionamento entre anfíbios anuros e bromélias da restinga de Regência, Linhares, Espírito Santo, Brasil

Some anuran amphibians use the bromeliads during the entire life cycle and others only as diurnal shelter. At the sandy coastal plain of Linhares, State of Espírito Santo, Southeastern Brazil, 676 bromeliads were examined, of which 303 of Aechmea blanchetiana (Baker) L. B. Smith., 1955, 287 of Aechmea nudicaulis (L.) Griseb., 1864, and 86 of Vrisea procera (Mart. Ex Schult. f.) Wittm, 1891. The morphometric and physical-chemical analysis of different bromeliads evidenced variations among plants. During the period sampled, six anuran species were found inside the plant axils. The hylid frog Phyllodytes luteolus (Wied, 1824) was the most abundant species (260 specimens). Its abundance was higher in the epiphyte bromeliad Vrisea procera. Phyllodytes luteolus had higher occurrences in bromeliads located at a transitional area between open and under the shrub vegetation. Specimens of Scinax alterus (Lutz, B., 1973) and Aparasphenodon brunoi Miranda-Ribeiro, 1920, were more frequent mainly in transitional areas; Bufo granulosus Spix, 1824 occurred in open and transitional areas, whereas Gastrotheca fissipis (Boulenger, 1888) and Leptodactylus fuscus (Schneider, 1799) were found only in bromeliads located in open areas.

Ecologia de Xylocopa (Neoxylocopa) cearensis (Hymenoptera, Anthophoridae) nas dunas litorâneas de Abaeté, Salvador, Bahia

The study was carried out in a 8.2 ha area in an environmental protection area of tropical sea coastal sand dune with "restinga" vegetation in Salvador, Bahia, northeastern Brazil. A total of 1760 bees of Xylocopa (Neoxylocopa) cearensis Ducke, 1910 were netted during the whole year on flowers of 43 plant species belonging to 26 botanic families. The majority of the individuals (79%) concentrated their foraging activity in five plant species. Individuals foraged all day long being the greatest activity between 8 h and 14 h. Similar proportions of young and old bees were sampled over the year. The density of substrates used for nesting was 4.56/ha. In total, 94% of the nests were found in branches of Agaristha revoluta (Spr.) DC. (Ericaceae). The great occurrence (68.7%) of old perforations indicates that the nests were used twice or more times by bees.

Freshwater sponges (Porifera, Demospongiae) indicators of some coastal habitats in South America: redescriptions and key to identification

Surveys for freshwater sponges were performed at several water bodies at sandy environments along a north-south direction of particularly the Brazilian coastal line. The results allowed for the distinction of four different species-specific environments along this coastal border. The main fact considered was the dominant or the sole recurrent occurrence of a single sponge species at one particular habitat. The first one is that of the lagoonal mesohaline habitats at the tropical and subtropical realms, indicated by Spongilla alba Carter, 1849. The second one refers to shallow ponds among dunes at the tropical area indicated by Corvoheteromeyenia heterosclera (Ezcurra de Drago, 1974). The third one is that of also shallow ponds close to the dune belt at the temperate region indicated by Racekiela sheilae (Volkmer-Ribeiro, De Rosa-Barbosa & Tavares, 1988). The fourth one is that of organically enriched environments, at the marginal areas of lagoons and mouth of small rivers, evolving towards freshwater muddy ponds and coastal swamps, not far from the ocean border: Ephydatia facunda Weltner, 1895 is the species to occupy this habitat with almost exclusiveness. The above species are thus proposed as indicators of such habitats and have their descriptions improved and that of their environments summarized. A taxonomic key based on the spicules of the four species is proposed. The results presented aim to contribute to the identification of spicules of these sponges in sediment columns recovered at the Brazilian and South American coastal area. Determination of paleo ocean borders are a present issue of upmost importance in what respects projections of timing and fluctuations of ascending/regressing sea levels.

Diet of the ichthyofauna associated with marginal vegetation of a mangrove forest in southeastern Brazil

The objective of this study was to analyze the diet of fish species that use the mangrove vegetation for shelter and feeding in a river southeastern Brazil. The fieldwork, including collecting and underwater observations, was carried out in the dry (July and August 2004) and in the rainy season (February and March 2005) in order to assess the existence of seasonal variation in the diets. Seven kinds of food items were consumed, two of plant origin and five of animal origin. Crustaceans predominated in the diet of most species, either in the form of unidentified fragments or discriminated in eight groups. The predominance of species using mainly a single food source (crustaceans, principally Ostracoda and Tanaidacea) and the existence of seasonal variation in the diets of some species became very evident in the analysis food niche breadth, with a predominance of dietary specialists. In the Rio da Fazenda mangrove, the submersed marginal vegetation was used by the ichthyofauna as a locale for foraging, and principally as cover by bottom-feeding species. These species may be using the vegetation for protection from aerial and aquatic predators, or even from the pull of the current during the turn of the tide. In the study area, the great diversity of crustaceans constitutes an important food source for most fish species which adjusted their diet according to seasonal changes in food availability and to interactions with other species.

Comparative analysis of tidepool fish species composition on tropical coastal rocky reefs at State of Ceará, Brazil

This study compared tidepool fish assemblages within and among habitats at Iparana and Pecém beaches, State of Ceará, Northeast Brazil, using visual census techniques. A total of 8,914 fishes, representing 25 families and 43 species were recorded. The most abundant taxon was Sparisoma spp, followed by Haemulon parra (Desmarest, 1823), Acanthurus chirurgus (Bloch, 1787) and Abudefduf saxatilis (Linnaeus, 1758). Haemulidae was the most abundant family in number of individuals, followed by Scaridae, Acanthuridae and Pomacentridae. Within- and between- site differences in species assemblages probably reflected environmental discontinuities and more localized features, such as pool isolation episodes, or environmental complexity, both acting isolated or interactively. The locality of Iparana was probably subjected to a greater fishing pressure and tourism than Pecém, a potential cause for the observed lowest fish abundance and biodiversity. We conclude that tidepool ichthyofauna may be quite variable between and within reef sites. Thus, observations taken from or damages caused on one area may not be generalized to or mitigated by the protection of adjacent sites.

Hatching and larval export of the intertidal crab Neohelice granulata in Mar Chiquita coastal lagoon, Argentina

Synchronization in the events of the reproductive cycle in female Neohelice granulata Dana, 1851 were studied from samples taken weekly and biweekly from September to December 2006 in the Laguna Mar Chiquita. The timing and larval hatching and synchronicity were inferred from numbers of ovigerous females and observing the stages of embryonic development. Synchronization in larval hatching also was observed in females in experiments in dark for a period of 48 hours, at three different salinities (10, 23 and 33 ppm). In addition plankton sampling were performed in order to study larval exportation at the field and its link to the tidal and light/dark cycles. We found that ovigerous females of N. granulata have a marked synchronization in embryonic development which results in that most of berried females are close to hatching within a period of maximum tidal range (days). Within this period, there is a synchronization of hatching at a time scale of hours, governed by environmental conditions. The salinity range used in this study (10-32‰) did not affect hatching synchronicity neither time to hatch. Hatching was synchronized according to endogenous rhythms governed mainly by the tidal cycle and secondarily by the breadth of it. It is also conditioned by the light-dark cycle through an exogenous cycle, so that the hatchings would occur mostly at night high tides.

Reproductive strategy of a non-annual rivulid in a perennial wetland

ABSTRACT Atlantirivulus riograndensis (Costa & Lanés, 2009) is a fish registered to the basin of Patos lagoon and the adjacent coastal plains in southern states of Rio Grande do Sul and Santa Catarina, Brazil, found in shallow water courses with that have large quantities of aquatic vegetation and forest edges. The objective of this study was to investigate the reproductive strategy and tactics of this species including the sex ratio, the length at first maturity, spawning type, fecundity and the possible associations among reproduction and abiotic factors. Sampling of specimens occurred in perennial wetlands within the Banhado dos Pachecos wildlife refuge, in the city of Viamão, state of Rio Grande do Sul, Brazil, which is a conservation unit that belongs to an area of environmental protection in the Pampa Biome. The capture of 30 A. riograndensis specimens per month occurred from January to December of 2012. A total of 188 females and 172 males were captured and the total sex ratio was 1:1 in the sampled population. Sexual maturity of the species occurs after 13.59 and 11.92 mm (SL) for females and males, respectively. Both a multiple spawning and a long reproductive period (since August to March) were confirmed by the presence of post-ovulatory follicles that were observed through histological analysis and the values of the gonadosomatic index in females considered spawning capable. The average absolute fecundity of the species is of 19.33 (± 6.18) vitellogenic oocytes in mature ovaries. No significant relationship was found between mean GSI and the abiotic data. Reproductive tactics presented by A. riograndensis indicate a species with an opportunistic reproductive strategy, following the pattern of other species of the Rivulidae family.

New or rare frogs from the Coastal Ranges of Brazil: eleutherodactylus venancioi n.sp., E. hoehnei n.sp. Holoaden bradei n.sp. e H. lüderwaldti Mir. Rib., 1920

Field-work in the sierras near the sea-board of south-eastern Brazil continues to yield new or rare frogs. Four more of these forms are presented here. Two of them, both new, are put into the genus Eleutherodactylus, to which they belong by their general habitat, morphology, and also by the osteological characters. They differs from the known regional species of this genus only by the wider and shorter disks of some of the digits and the more lanceolate build. The other two species belong to the very little known genus Holoaden, established by MIRANDA RIBEIRO in 1920. One of them is his type-species, H. lüderwaldti, which continues to be very rare. The other, H. bradei, is new. It seems endemic to the Upper Itatiaia and is very plentiful there.

Trypanorhynch Cestodes of Commercial Fishes from Northeast Brazilian Coastal Waters

A large scale investigation on trypanorhynch cestode infestation of tropical marine fishes was carried out along the Northeast Brazilian coast in the summer of 1991 and 1993. A total of 798 fish specimens belonging to 57 species and 30 families were examined. Metacestodes of 11 different trypanorhynchs were found: Callitetrarhynchus gracilis, Dasyrhynchus giganteus, Grillotia sp., Nybelinia edwinlintoni, N. indica, N. senegalensis, Nybelinia c.f. lingualis, Otobothrium cysticum, Pseudolacistorhynchus noodti, Pseudotobothrium dipsacum and Pterobothrium kingstoni. Scanning electron microscopy was used to clarify details of the tentacular armature of some species. Rose-thorn shaped hooklets, regularly arranged like microtriches, are described from the bothridial surface of N. edwinlintoni. Of the 57 fish species, 15 harboured trypanorhynch cestodes. Of these the mullid Pseudupeneus maculatus was the most heavily infested fish species, harbouring 5 different trypanorhynch species. P. noodti in P. maculatus had the highest prevalence (87%) and intensity (maximum = 63) of infestation. C. gracilis was the parasite with the lowest host-specificity. It could be isolated from 10 fish species. The cestode fauna of the Northeast Brazilian coast appears to be similar to that of the West African coast. Five of the trypanorhynch cestodes found during this study are common to both localities. The two single cases of intra musculature infestation in Citharichthys spilopterus and Haemulon aurolineatum by trypanorhynch cestodes indicate that marketability of the investigated commercially exploited fish species is inconsequential.

Redescription of Rhamnocercus stichospinus Seamster and Monaco, 1956 (Monogenea: Diplectanidae), parasitic on Menticirrhus americanus (Osteichthyes: Sciaenidae) from the Coastal Zone of the state of Rio de Janeiro, Brazil

Rhamnocercus stichospinus Seamster and Monaco, 1956 (Diplectanidae) parasitic on the sciaenid fish Menticirrhus americanus from the coastal zone of the State of Rio de Janeiro, is redescribed and recorded for the first time in the South American Atlantic Ocean. The generic diagnosis of Rhamnocercus is emended to accommodate the presence of confluent intestinal ceca in R. stichospinus.

Community ecology of the metazoan parasites of white croaker, Micropogonias furnieri (Osteichthyes: Sciaenidae), from the coastal zone of the State of Rio de Janeiro, Brazil

One hundred specimens of white croakers, Micropogonias furnieri (Desmarest 1823) (Osteichthyes: Sciaenidae) collected from Pedra de Guaratiba (23°01'S, 43°38'W), State of Rio de Janeiro, Brazil, from September 1997 to August 1999, were necropsied to study their parasites. The majority of the fish (95%) were parasitized by metazoan. Twenty-eight species of parasites were collected. The nematodes were the 40.5% of the total number of parasites specimens collected. Dichelyne elongatus was the most dominant species. Lobatostoma ringens, Pterinotrematoides mexicanum, Corynosoma australe, D. elongatus, and Caligus haemulonis showed a positive correlation between the host's total length and parasite prevalence and abundance. The monogenean P. mexicanum had differences in the prevalence and abundance in relation to sex of the host. The mean diversity in the infracommunities of M. furnieri was H=0.499±0.411, with correlation with the host's total length and without differences in relation to sex of the host. One pair of ectoparasites showed positive covariation, and two pairs of endoparasites showed positive association and covariation between their prevalences and abundances, respectively. Negative association or covariations were not found. The dominance of endoparasites in the croakers parasite infracommunities reinforced the differences found in sciaenids from the South American Pacific Ocean, in which the ectoparasites are dominant.

Community ecology of the metazoan parasites of pink cusk-eel, Genypterus brasiliensis (Osteichthyes: Ophidiidae), from the coastal zone of the State of Rio de Janeiro, Brazil

Fifty-five specimens of pink cusk-eel, Genypterus brasiliensis Regan, 1903 (Osteichthyes: Ophidiidae) collected from the coastal zone of the State of Rio de Janeiro, Brazil (approx. 21-23°S, 41-45°W), from September 2000 to January 2001, were necropsied to study their parasites. All fish were parasitized by one or more metazoan. Fourteen species of parasites were collected. G. brasiliensis is a new host record for nine parasite species. The larval stages of cestodes and the nematodes were the majority of the parasite specimens collected, with 38.4% and 36.5%, respectively. Cucullanus genypteri was the dominant species with highest prevalence and/or abundance. The parasites of G. brasiliensis showed the typical overdispersed pattern of distribution. Six parasite species showed correlation between the host's total body length and prevalence and abundance. Host sex did not influence prevalence and parasite abundance of any parasite species. The mean diversity in the infracommunities of G. brasiliensis was H= 0.364 ± 0.103, with correlation with the host's total length and without differences in relation to sex of the host. One pair of adult endoparasites (C. genypteri and A. brasiliensis) showed positive covariations between their abundances. Negative association or covariation was not found. Differences between the qualitative and quantitative aspects of the parasite community of G. brasiliensis from Rio de Janeiro and Argentina suggest the existence of two population stocks of pink cusk-eel in the South America Atlantic Ocean.