Effect of Forest Fragmentation on Tick Infestations of Birds and Tick Infection Rates by Rickettsia in the Atlantic Forest of Brazil

Habitat loss and modifications affect biodiversity, potentially contributing to outbreaks of infectious diseases. We evaluated if the patch sizeinfragmented areas of Atlantic Forest in southeastern Brazil influences the diversity of forest birds and consequently the prevalence of ticks on birds and the rickettsial infection of these ticks. During 2 years, we collected ticks from birds in 12 sites: four small forest patches (80–140 ha), four large ones (480–1,850 ha), and four forest control areas within the much larger Morro do Diabo State Park (~36,000 ha). A total of 1,725 birds were captured (81 species, 24 families), from which 223 birds were infested by 2,339 ticks of the genus Amblyomma, mostly by the species A. nodosum. Bird diversity and richness were higher in larger than smaller forest fragments. The prevalence of ticks on birds was inversely correlated with bird diversity and richness. Among 174 A. nodosum tested for rickettsial infection by polymerase chain reaction, 51 were found to be infected by Rickettsia bellii or Rickettsia parkeri. However, tick infection rates by Rickettsia spp. were not statistically different between forest patch sizes. The higher prevalence of ticks on birds in degraded patches might be caused by a dominance of a few generalist bird species in small patches, allowing an easier transmission of parasites among individuals. It could also be related to more favorable microclimatic conditions for the free-living stages of A. nodosum in smaller forest fragments.The higher burden of ticks on birds in smaller forest fragments is an important secondary effect of habitat fragmentation, possibly increasing the likelihood of Rickettsia contagion.     

Fishes of the southeastern Brazil Atlantic Forest

The largest preserved areas of Atlantic Forest are located in the southeastern region of Brazil. Estuaries, mangroves, rivers and streams are home to a community of fish that is still poorly understood. The composition of fish species and their relationships with environmental conditions were used to identify homogeneous areas within a landscape of 33,000 km². A total of 6,542 specimens, representing 124 species and 13 orders of bony fishes were collected at 102 sampling stations. Resulting scores from a canonical correspondence analysis applied to biological and environmental data were used in a cluster analysis to identify fish species with similar spatial distributions and localities with similar fish fauna and abiotic conditions. Five micro-regions were identified, with homogeneous compositions of species, allowing better planning of conservation of aquatic biodiversity. Despite a high degree of preservation, impacts due to deforestation, drainage of wetlands and overfishing were detected, as well as the introduction of 41 exotic species.     

Orchid bee fauna (Hymenoptera: Apidae: Euglossina) of Atlantic Forest fragments inside an urban area in southeastern Brazil

Male orchid bees were collected by chemical baiting in four forest fragments in parks of the city of Belo Horizonte, Minas Gerais, southeastern Brazil. One thousand three hundred and twenty-five males belonging to 14 species were captured within one year. The capture data were compared through correlation tests. The data suggest that abundance of orchid bees tend to increase with fragment size, although no correlation between species richness and fragment size was obtained. The results presented herein suggest that forest fragments in a large city may be of importance concerning conservation of orchid-bee faunas.     

Small mammal populations of an agroecosystem in the Atlantic Forest domain, southeastern Brazil.

This study reports 2 years of the population dynamics and reproduction of a small mammal community using the removal method. The study was conducted in a rural area of the Atlantic Forest, in Sumidouro, Rio de Janeiro State, Brazil. The population sizes, age structure and reproduction were studied for the four most common species in the study area. The overall diversity was 1.67 and ranged between 0.8 to 1.67. The species richness was 13 considering the whole study. The most abundant species were the rodents Nectomys squamipes (n = 133), Akodon cursor (n = 74), Oligoryzomys nigripes (n = 25) and the marsupials Didelphis aurita (n = 58) and Philander frenatus (n = 50). Seven other rodents were captured once: Necromys lasiurus, Akodon montensis, Sooretamys angouya, Oecomys catherine, Oxymycterus judex, Euryzygomatomys spinosus and Trinomys iheringi. There were higher peaks for diversity and species richness during the winter (dry) months, probably due to higher food availability. The marsupials had a seasonal reproduction with highest population sizes at the end of the rainy seasons. Nectomys squamipes reproduced mostly during rainy periods. Akodon cursor reproduced predominantly in the winter with the highest population peaks occurring during this season. The analysis of the population dynamics of the rodent species indicated that no species behaved as an agricultural pest, probably due to the heterogeneous landscape of high rotativity of vegetable cultivation. Rodent populations were more susceptible to the removal procedure than marsupial ones.     

Feeding behavior of Geoffroy's marmoset (Callithrix geoffroyi) in an Atlantic forest fragment of South-eastern Brazil

We report on the diet and feeding behaviour of a group of Geoffroy's marmosets (Callithrix geoffroyi) in an Atlantic forest fragment in south-eastern Brazil, studied during the period February 1993 to Januaray 1994. Major food categories were gums (68.6%) fruits (15%), and small animal prey (invertebrates 14.6% and vertebrates 0.8%). Dietary changes were observed between the wet and dry seasons, although they were not statistically significant. Insects and gums were consumed throughout the year but fruits were more prevalent in the diet in the wet season. Plant species exploited for their gums includedInga stipularis, followed byAcacia paniculata, Paulinia carpopodia, andBauhinia angulosa. Chemical analysis of the gum of the four species most used all presented high values for carbohydrates and crude proteins. Fruits of an unidentified species of Myrtaceae (sp. 2) were consumed the most. Animal prey consisted mainly of insects, arachnids, snails, and in three cases, lizards and frogs, with orthopterans being the most prevalent insect prey. This study demonstrates thatC. geoffroyi efficiently exploits resources typically available in secondary and disturbed forest habitat. The main threat to the species is forest destruction, degradation, and fragmentation, but the management of small forest fragments may be an effective corservation strategy.     

Fish assemblage structure in an estuary of the Atlantic Forest biodiversity hotspot (southern Brazil)

We described the fish assemblage in the estuary of the Guaraguaçu River (one of the largest tributaries of the Paranaguá Bay Estuary, located within Brazil’s Atlantic Forest Biosphere Reserve) from June 2005 to May 2006, and assessed the seasonal and spatial effects of abiotic environmental attributes on the fish assemblage structure. Despite some oscillations in salinity, the upper and lower estuaries had year-round persistent oligohaline and polyhaline conditions, respectively. Despite high species richness (55 species), the Guaraguaçu River Estuary fish community contains a few dominant taxa; 11% of the richness accounts for >60% of its density and biomass. The most abundant species (in terms of both biomass and density) was Atherinella brasiliensis. Species whose densities were most strongly associated with the upper estuary were Centropomus parallelus, Ctenogobius schufeldti, Eucinostomus melanopterus, Platanichthys platana, Trinectes paulistanus, and Eugerres brasilianus. Those whose densities were most strongly associated with the lower estuary were A. brasiliensis, Sphoeroides greeleyi, Eucinostomus argenteus, Sphoeroides testudineus, Diapterus rhombeus, and Harengula clupeola. Throughout the year, canonical correspondence analysis identified: (1) the pattern of horizontal stratification of salinity along the river as being the most important variable for explaining most of the fish fauna structure; and (2) a strong relationship between the fish fauna and the salinity gradient along the estuary. Analysis of similarity further confirmed that each estuarine zone supports a year-round persistent and relatively homogeneous fish species assemblage. Total mean density and biomass remained constant over time in each estuarine habitat, but density shifted in the most abundant species, which appears related to recruitment patterns. Such species and abundance persistence likely occurs because seasonal rainfall-induced changes in river discharge are not sufficient to significantly shift runoff and salinity and thus fish assemblage structure (species composition, density and biomass) along the estuary. Such a lack of seasonal fish fauna movement as a response to changes in river flow contrasts with other estuarine systems around the world.     

Variation in liana abundance and biomass along an elevational gradient in the tropical Atlantic Forest (Brazil)

Lianas play a key role in forest structure, species diversity, as well as functional aspects of tropical forests. Although the study of lianas in the tropics has increased dramatically in recent years, basic information on liana communities for the Brazilian Atlantic Forest is still scarce. To understand general patterns of liana abundance and biomass along an elevational gradient (0–1,100 m asl) of coastal Atlantic Forest, we carried out a standard census for lianas ≥1 cm in five 1-ha plots distributed across different forest sites. On average, we found a twofold variation in liana abundance and biomass between lowland and other forest types. Large lianas (≥10 cm) accounted for 26–35% of total liana biomass at lower elevations, but they were not recorded in montane forests. Although the abundance of lianas displayed strong spatial structure at short distances, the present local forest structure played a minor role structuring liana communities at the scale of 0.01 ha. Compared to similar moist and wet Neotropical forests, lianas are slightly less abundant in the Atlantic Forest, but the total biomass is similar. Our study highlights two important points: (1) despite some studies have shown the importance of small-scale canopy disturbance and support availability, the spatial scale of the relationships between lianas and forest structure can vary greatly among tropical forests; (2) our results add to the evidence that past canopy disturbance levels and minimum temperature variation exert influence on the structure of liana communities in tropical moist forests, particularly along short and steep elevational gradients.     

Food habits of sympatric opossums coexisting in small Atlantic Forest fragments in Brazil

The diets of sympatric species of opossums coexisting in small (<10 ha) Atlantic Forest fragments were studied at Poço das Antas Biological Reserve, southeastern Brazil. Food items consumed by Caluromys philander and Didelphis aurita were investigated through the analysis of faecal contents, and compared with the diet of Micoureus demerarae analysed in a previous study. The major diet components for all three species were arthropods and fruits, with a high richness of items of both feeding categories; feathers were also found in the diet of D. aurita. The most frequent insect orders overall were Hymenoptera and Coleoptera, and most seeds were from plants of secondary vegetation such as Cecropia and Piper. The diets showed little variation along time and space for all three species. Diets were also similar among species, except for a larger consumption of Arachnida and Diplopoda and a smaller consumption of Lepidoptera by D. aurita when compared to M. demerarae. Diversity of food items was lower for C. philander when compared with either other species. There was a high feeding niche overlap between species, suggesting that differentiation in diet composition would not be enough to allow coexistence of the three species in small fragments. Coexistence may rather be allowed by vertical segregation and/or by differences in prey size.     

Tick infestations of birds in coastal Georgia and Alabama

Mist-netted birds were examined for ticks on Jekyll Island, Glynn Co., Georgia (32 bird species) in 1996-1998, and at Fort Morgan, Baldwin Co., Alabama (36 species) in 1998 during fall migration. Sixty-two (14.7%) of 423 birds from Jekyll Island and 22 (13.3%) of 165 birds from Fort Morgan were infested with ticks. The mean number of ticks per infested bird was 2.0 on Jekyll Island and 6.3 at Fort Morgan. Ten species of birds were infested with ticks on Jekyl1 Island where 87% of all ticks were recovered from 3 species: the common yellowthroat (Geothlypis trichas), gray catbird (Dumetella carolinensis), and northern waterthrush (Seiurus noveboracensis). Eight species of birds were infested with ticks at Fort Morgan where 83% of all ticks were recovered from 3 species: the brown thrasher (Toxostoma rufum), swamp sparrow (Melospiza georgiana), and common yellowthroat. Six species of ticks (Amblyomma americanum, Amblyomma maculatum, Haemaphysalis leporispalustris, Ixodes brunneus, Ixodes minor, and Ixodes scapularis) were recovered from the Georgia birds, whereas 3 species (A. maculatum, H. leporispalustris, and Ixodes dentatus) were recovered from the Alabama birds. Attempts to isolate Borrelia burgdorferi sensu stricto, the etiologic agent of Lyme borreliosis, from Ixodes spp. ticks recovered from birds were unsuccessful.     

Diversity and abundance of climbers from the Atlantic Forest, southeastern Brazil

Climbing plant community composition and abundance was compared between the Alto da Serra de Paranapiacaba Biological Reserve (ASPRB) and the Nascentes de Paranapiacaba Municipal Natural Park (NPMNP), two protected areas in the largest Atlantic Forest remnant, southeastern Brazil. Climbing plants ≥1 cm in diameter were sampled in 52 quadrats of 10 × 20 m (1.04 ha). From these data we calculated the Shannon–Wiener diversity index, calculated abundance and importance values for families, performed a principal coordinate analysis, and created a similarity dendrogram (TWINSPAN). The composition and abundance of species between ASPRB and NPMNP differed significantly due to the successional state of the ASPRB forest, which was affected by more recent disturbance. There we found 34 species, while in the NPMNP, species richness was 72, with only 24 species in common. The two areas formed two groups corresponding to two distinct floristic subsets. These montane forests were characterized by a predominance of species of the Asteraceae. The high species richness, floristic composition, and community composition reflect the greater degree of conservation in the area of NPMNP. The high density and community composition of climbers in the more conserved area of rainforest may be due to the low intensity of disturbance.     

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.     

Three new species of melastomataceae from the southeastern Atlantic Forest of Brazil

Three species are described here that occur in montane and high-montane forests in Southeastern Brazil.Miconia shepherdii belongs to sectionGlossocentrum and occurs on the Serra da Mantiqueira, on the border between the states of São Paulo, Minas Gerais, and Rio de Janeiro.Miconia kollmannii belongs to sectionHypoxanthus (formerChaenanthera) and occurs in the state of Espírito Santo.Ossaea suprabasalis was also collected in the state of Espírito Santo.     

Searching for bioindicators of forest fragmentation: passerine birds in the Atlantic forest of southeastern Brazil

Aiming to evaluate the potential of Passerine birds as bioindicators of forest fragmentation, we studied the avifauna in the mountain region of the state of Rio de Janeiro by mist-netting between 2001 and 2005. We sampled six sites, including four small fragments (from 4 to 64 ha) in an agricultural area (Teresópolis), one second-growth forest (440 ha - Miguel Pereira) and a continuous forest (10,600 ha, Serra dos Org?os National Park - SONP). Indicator Species analysis and a Monte Carlo test were run to detect associations between species and sites, considering at least 30% of perfect indication and a significant value for the statistical test, only considering species with at least 10 captures. A total of 30 Passerine birds were sampled, and due to their association to the largest area (SONP), we considered Sclerurus scansor, Mionectes rufiventris, Chiroxiphia caudata and Habia rubica as the best indicators for this area. Five species were more captured not by chance in the 440 ha second-growth: Conopophaga melanops, Myiobius barbatus, Myrmeciza loricata, Philydor atricapillus and Schiffornis virescens and no species were related to any small fragment. This analysis has identified specialized Passerine species in many aspects (foraging substract, needs for nesting, rarity status), and it can be a valuable tool for detecting possible bioindicators.     

Floristic similarities between lowland and montane areas of Atlantic Coastal Forest in Northeastern Brazil

Studies undertaken in the Atlantic Coastal Forest have revealed a notable floristic heterogeneity within this vegetation type in NE Brazil. However, there is still a great need for detailed comparisons of the floristic relationships between the various forest types found there. This work presents an analysis of the floristic similarity (at the species level) of these forest as revealed by floristic surveys, with the aim of better understanding and defining this vegetation. Using a binary matrix, grouping, ordering, and TWINSPAN analysis were performed on 742 tree/shrub species listed in 35 different plant surveys. These tree/shrub species were divided by these analysis into two large floristic groups – ombrophilous and semideciduous. The semideciduous group was formed, in general, by forest areas located at altitudes above 700 m (montane forests), and could itself be divided into two subgroups. The first subgroup was located more inland (Pernambuco), while the second subgroup was located nearer the coast (within the states of Pernambuco and Ceará). The ombrophilous group was quite heterogeneous, but could also be divided into two floristic subgroups: i) lowland forests (below 100 m a.s.l) in the states of Pernambuco, Paraíba, and in two areas of Bahia, as well as some montane forests (in Pernambuco, between 640 and 900 m a.s.l.); ii) lowlands forests in the states of Alagoas and Bahia. This latter subgroup is the largest and best defined, and has the highest degree of internal similarity. Nonetheless, it can be further subdivided into two smaller classes, one in Alagoas and the other in Bahia State. The results of this study demonstrate that the concept of the Atlantic Coastal Forest could also include montane ombrophilous forests in Pernambuco State, as these forests form a single floristic unit together with lowland forests in that state. This revised version was published online in June 2006 with corrections to the Cover Date.