Atlantic Forest Habitat Research Articles

Three new species of orb-weaver spiders (Araneidae) from Humid Chaco and Atlantic Forest habitats in southern Paraguay

Three new species of orb-weaver spiders (Araneidae) from Humid Chaco and Atlantic Forest habitats in southern Paraguay

Hydraulic tradeoffs underlie local variation in tropical forest functional diversity and sensitivity to drought.

Tropical forests are important to the regulation of climate and the maintenance of biodiversity on Earth. However, these ecosystems are threatened by climate change, as temperatures rise and droughts' frequency and duration increase. Xylem anatomical traits are an essential component in understanding and predicting forest responses to changes in water availability. We calculated the community-weighted means and variances of xylem anatomical traits of hydraulic and structural importance (plot-level trait values weighted by species abundance) to assess their linkages to local adaptation and community assembly in response to varying soil water conditions in an environmentally diverse Brazilian Atlantic Forest habitat. Scaling approaches revealed community-level tradeoffs in xylem traits not observed at the species level. Towards drier sites, xylem structural reinforcement and integration balanced against hydraulic efficiency and capacitance xylem traits, leading to changes in plant community diversity. We show how general community assembly rules are reflected in persistent fiber-parenchyma and xylem hydraulic tradeoffs. Trait variation across a moisture gradient is larger between species than within species and is realized mainly through changes in species composition and abundance, suggesting habitat specialization. Modeling efforts to predict tropical forest diversity and drought sensitivity may benefit from adding hydraulic architecture traits into the analysis.

A new species ofAkodonMeyen, 1833 (Rodentia: Cricetidae: Sigmodontinae) endemic from the Brazilian Cerrado

AbstractAkodon is the second most diverse genus of sigmodontine rodents, comprising 40 extant species. Widely distributed through different environments of South America, the genus ranges from forested to open-vegetation areas, from semiarid to mesic regions, and from Andean altitudes to the lowlands of eastern Brazil. In Brazil, most species are from the Atlantic Forest, inhabiting lowland and montane habitats, with a few taxa also present in areas transitional with the Cerrado and Pantanal. Based on an integrative approach of genetics (cytogenetic and molecular data) and morphology (qualitative and quantitative external and craniodental data), we present in this contribution the hypothesis of a new species of Akodon based on specimens collected in the southwestern limit of the Cerrado domain, in the seasonally dry forests of the Serra da Bodoquena, Mato Grosso do Sul, Brazil. The new species was recovered as a distinct lineage sister to Akodon philipmyersi, a poorly known species from the Northern Campos grasslands of Misiones Province, Argentina, and can be distinguished from its congeners by its karyotype (2n = 40, FN = 40), morphology (morphometric, pelage, and skull characters), as well as by its degree of genetic divergence (above 7.5% in Cytb sequences). This new species is endemic to the Cerrado, one of the world’s biodiversity hotspots, and to Serra da Bodoquena, one of the top priority areas for conservation in Brazil. Moreover, the new species increases the number of lineages of Akodon in Brazil, emphasizing the richness and endemism currently found in the Cerrado domain, and the importance of the open formations to the diversification of Neotropical taxa.

Evolution of Appendicular Specializations for Fossoriality in Euryzygomatomyine Spiny Rats across Different Brazilian Biomes (Echimyidae, Hystricognathi, Rodentia)

The evolution of subterranean and fossorial rodents has been linked to the Neogene climatic shift to xeric conditions leading to open vegetation, like prairies and grasslands; most modern subterranean rodents occur in arid and open areas. Among South American spiny rats (family Echimyidae), the subfamily Euryzygomatomyinae includes both fossorial (Clyomys and Euryzygomatomys) and ambulatorial (Trinomys) genera, some of them endemic to open vegetated areas and other ones restricted to forested regions. The closely related genus Carterodon is also a fossorial rodent endemic to open vegetated areas. If the open environments constitute a determinant factor triggering the evolution of fossoriality in these spiny rats, it is expected that the fossorial lineages evolving since the Miocene in open environments (Carterodon sulcidens and Clyomys laticeps) show morphologies more specialized for digging than those currently restricted to Atlantic Forest habitats (Euryzygomatomys spinosus). Moreover, it is likely that Trinomys species specialized for xeric environments (T. albispinus and T. yonenagae) show incipient adaptations for fossoriality. The appendicular skeleton of three fossorial and five ambulatorial echimyid species were morphometrically analyzed with multivariate statistical approaches in order to test these presuppositions. The analyses showed that the appendicular morphology of T. yonenagae and T. albispinus, in comparison with the Atlantic Forest Trinomys species, and of C. sulcidens and C. laticeps in relation to E. spinosus are more adapted to scratch-digging activities, corroborating the hypothesis that open environments favor the evolution of fossoriality in spiny rats.

A Revision of Colanthelia (Poaceae: Bambusoideae: Bambuseae: Arthrostylidiinae) and New Species for the Atlantic Forest

The first revision of the Neotropical woody bamboo genus Colanthelia is here presented. Updated morphological descriptions of the species, comments, illustrations, and keys to the species (one based on vegetative characters only and the other based on vegetative plus reproductive characters) are provided. Colanthelia consists of nine species, all characteristic of the Atlantic forest habitat, three of which are described and illustrated as new in this treatment: C. kinoshitae, which has fimbriate auricles on the apex of both the culm and foliage leaf sheaths and adaxially glabrous to glabrate culm leaf sheaths and glabrous girdles; C. secundiflora, characterized by its erect culm leaf blades, secund spikelets, and the lemmaswith dark spots; and C. sparsiflora, which has synflorescences with spikelets widely separated from each other. Eight species are endemic to Brazil and one, C. rhizantha, is found in both Brazil and Argentina. Colanthelia distans and C. macrostachya are probably extinct. Colanthelia lanciflora, originally described as a species of Aulonemia, is here excluded from Colanthelia, and reassigned to Aulonemia.

Compensatory dynamics on the community structure of fruit-feeding butterflies across hyper-fragmented Atlantic forest habitats

The creation of forest edges promotes a drastic extirpation of forest-dependent species across tropical fragmented landscapes. Yet, this loss of forest-dependent species can be compensated by the proliferation of disturbance-adapted species (winner-loser replacement) maintaining community-level attributes in altered habitats. Here, we test whether this replacement reflects a sort of compensatory dynamics, which alters patterns of species richness, abundance, ecological composition and β-diversity (multiplicative diversity decompositions of Hill numbers) of fruit-feeding butterflies between non-disturbed and disturbed habitats in two fragmented landscapes of the Brazilian Atlantic forest. Additionally, we examined the determinants of these compensatory dynamics analyzing the effects of patch (core area and edge density) and landscape structure (proximity index) on these community-level attributes. Our results show that (1) habitat loss and fragmentation can in fact reorganize natural communities (i.e., altering community level attributes) by favoring disturbance-adapted species, while negatively impacting forest dependent species; (2) disturbed habitats showed more species and individuals than non-disturbed habitats with a clear segregation in terms of species composition; (3) disturbed habitats exhibited lower β-diversity than non-disturbed habitats regarding dominant species, and (5) core area (positively) and edge density (negatively) were significantly related to forest-dependent species (in terms of abundance and diversity). Thus, our results indicate that compensatory dynamics is extrapolating the threshold of edge-affected habitats and highlight that the conservation value of human-modified landscapes depends on the nature of the ecological groups responsible for the increased β-diversity.

Phylogeny and biogeography of Phyllomys (Rodentia: Echimyidae) reveal a new species from the Cerrado and suggest Miocene connections of the Amazon and Atlantic Forest

Phyllomys is the most species-rich genus among spiny tree rats of the family Echimyidae and includes members widely distributed throughout the Atlantic Forest of South America. Among recognized species recovered in previous studies, 4 lineages are unnamed and their taxonomic distinctness needs further investigation. Biogeographic analyses recovered an Amazonian ancestor of the basal lineage leading to living Phyllomys, suggesting ancient connections between the 2 largest South American rainforests, and presence of rainforest corridors within the central Brazilian dry biomes. Based on exhaustive taxonomic sampling of Phyllomys, applying multigene phylogenetic methods, and morphological and karyological data, we described a new species of Phyllomys from central Brazil. Geographical records from the center of the Cerrado biome of central Brazil indicate an unexpected location for the distribution of the genus, given the contrast between the physical and biological characteristics of the Cerrado and Atlantic Forest habitats. Contrary to previous studies, the analysis of the ancestral geographic range performed here suggests a Cerrado ancestral distribution for Phyllomys during the late Miocene. This result favors the hypothesis of a past link between the Amazon and Atlantic Forest in central Brazil, through the region occupied today by the dry Cerrado, and that forest expansions and contractions may have occurred in Brazilian dry biomes over the course of the Tertiary.

The Annual Cycle and Natural History of a Subtropical Atlantic Forest Avifauna in Paraguay

We studied the avifauna in a subtropical humid forest around Hotel El Tirol, Department of Itapua, Paraguay. The study site is part of the Atlantic Forest biome, a critically endangered biodiversity hot spot. We recorded 205 species of birds in 45 families and provide information on their annual cycles and natural history from collected specimens and field observations. Increased knowledge will contribute to efforts to maintain and manage the bird species of this endangered biome. The annual cycle of the avifauna at El Tirol closely resembled that of birds at north temperate and subtropical latitudes. Birds entering reproductive phases were likely responding to increasing photoperiod and rainfall. In general, breeding was initiated in mid-August and began to decline in late November. Molt rose sharply in early December and continued into April, overlapping with breeding in 16 species. In some species, males replaced juvenal plumage with an immature plumage easily distinguishable from the adult form, which they acquired after several years. Most males in immature plumage bred. For most species skull pneumatization in young of the year was completed during their first year. In several species, however, the pneumatization process extended into year 2, and in other taxa, complete pneumatization requires multiple years or never occurs. The birds at El Tirol were predominantly insectivorous. About a quarter of the specimens in 134 species had noticeable body fat. In general, fat deposition peaked in June, with lesser peaks from February to mid-March and in late August and September. Twenty-seven of the species that we recorded were migratory. We compared the species of birds recorded at El Tirol with those recorded from San Rafael National Park, a large tract of Atlantic Forest farther north in Paraguay with a much more extensive avifauna. Some of the species we failed to record were likely overlooked. However, El Tirol is at the southwestern limit of the Atlantic Forest habitat; absences may reflect faunal attenuation as species reach the limits of their ecological ranges. The lower numbers may also indicate that diversity in forest patches is reduced. Regardless, such patches will play an important role in maintaining the Atlantic Forest avifauna.

The associated beetle fauna of Hohenbergia augusta and Vriesea friburgensis (Bromeliaceae) in southern Brazil

ABSTRACTThis work presents the first list of Coleoptera species found in Hohenbergia augusta (Vell.) E. Morren and Vriesea friburgensis Mez. (Bromeliaceae), in Santa Catarina state, Brazil, most of them identified to the species level. Beetle species richness and composition were compared between the bromeliad species and between Atlantic forest and restinga habitats. Biological information on some beetle species is reported for the first time. We also discuss the aquatic habit of the hydrophilid Lachnodacnum luederwaldti Orchymont, 1937 (Sphaeridinae) inside bromeliad phytotelms.

Cultural viability of reintroducing the ecologically extinct Alagoas Curassow (Pauxi mitu Linnaeus, 1766) to Northeast Brazil

The Alagoas Curassow (Pauxi mitu) became extinct in the wild in the 1980's through a combination of loss/degradation of its Atlantic Forest habitat and over-hunting. Ambitious plans are now underway to reintroduce captive-reared Curassows using a patchwork of protected forest fragments on private lands. Although the planned reintroduction sites are broadly ecologically suitable, it is not clear that the threats from hunting and habitat disturbance have been removed. In other words, the cultural (as opposed to biological) suitability and viability of these sites is unknown. We used a semi-structured social survey of 402 residents who live near three proposed reintroduction sites to evaluate the cultural suitability of the reintroduction. Specifically, we adopted a multimodel inference approach to identify socio-demographic characteristics (e.g., age, gender, education level, duration of residence), knowledge (e.g., of local biodiversity and hunting practices) and behaviors (e.g., bushmeat consumption and firewood collection) that influence support for the reintroduction. Respondents were generally positive to bringing the Curassow back, though our data indicates that hunting is still a major part of the local culture. Support for the reintroduction was most strongly associated with older and, especially, better educated residents. Residents from different reintroduction sites also differed in their professed levels of support. Our results highlight the importance of focused environmental educational programmes to improve the cultural feasibility of this flagship reintroduction for Northeast Brazil.

Relation between Water Balance and Climatic Variables Associated with the Geographical Distribution of Anurans.

Amphibian species richness increases toward the equator, particularly in humid tropical forests. This relation between amphibian species richness and environmental water availability has been proposed to be a consequence of their high rates of evaporative water loss. In this way, traits that estimate water balance are expected to covary with climate and constrain a species’ geographic distribution. Furthermore, we predicted that coexisting species of anurans would have traits that are adapted to local hydric conditions. We compared the traits that describe water balance in 17 species of anurans that occur in the mesic Atlantic Forest and xeric Cerrado (savannah) habitats of Brazil. We predicted that species found in the warmer and dryer areas would show a lower sensitivity of locomotor performance to dehydration (SLPD), increased resistance to evaporative water loss (REWL) and higher rates of water uptake (RWU) than species restricted to the more mesic areas. We estimated the allometric relations between the hydric traits and body mass using phylogenetic generalized least squares. These regressions showed that REWL scaled negatively with body mass, whereas RWU scaled positively with body mass. Additionally, species inhabiting areas characterized by higher and more seasonally uniform temperatures, and lower and more seasonally concentrated precipitation, such as the Cerrado, had higher RWU and SLPD than species with geographical distributions more restricted to mesic environments, such as the Atlantic Forest. These results support the hypothesis that the interspecific variation of physiological traits shows an adaptation pattern to abiotic environmental traits.

Forest fragmentation does not matter to invasions by Hovenia dulcis

Testing whether biological invasions can be facilitated by habitat fragmentation can provide important insights for the study of invasion ecology. Hovenia dulcis is considered an aggressive non-native species in subtropical Atlantic forest ecosystems and following the assumptions of invasion ecology we hypothesized it would occur mainly in smaller forest remnants, which are more susceptible to edge effects compared to larger ones. In this study, we verified the relationships between H. dulcis invasion on forest remnants and the current habitat fragmentation and tested whether both occurrence and abundance of this species are driven by landscape and habitat variables. We selected 30 forest fragments in initial, middle or late successional stages and verified the occurrence and abundance of trees and saplings of H. dulcis. We evaluated spatial autocorrelation and the influence of landscape and habitat metrics on occurrence and abundance of such species and the influence of fruiting trees (adults) on the abundance of non-adult individuals. We found that H. dulcis distribution was not related to geographic distance among remnants. The occurrence of adult H. dulcis was directly associated to closed-canopy areas and remnant shape and, contrary our initial hypothesis, not related to remnant size. The occurrence of adult trees increased H. dulcis regeneration leading to higher sapling abundance. High abundance of H. dulcis saplings close to adult trees pointed out the successful colonization of recently invaded Atlantic forest remnants. We showed that this invasive tree species successfully invades closed-canopy forest fragments, which highlight undisturbed subtropical Atlantic forest habitats are as susceptible to biological invasions as disturbed ones.

Use of space by the marsupials Gracilinanus microtarsus (Gardner and Creighton, 1989) and Marmosops incanus (Lund, 1840) in an Atlantic Forest of southeastern Brazil

The use of space by animals is determined by environmental conditions, biological and ecological adaptations and interactions and mostly by resource availability. We sampled two species of Neotropical mammals to investigate their use of different strata in Atlantic Forest habitat in Brazil, as well as the home range sizes and movements of both sexes of each species. We found no difference in home ranges and movements between the sexes and species, but we found differences in the use of strata, with Gracilinanus microtarsus mostly using the canopy and Marmosops incanus using the ground. Gracilinanus microtarsus males mostly use the understorey in the wet season and the canopy in the dry season. We believe that these patterns of strata use reflect intrinsic characteristics of the species; and the shifts in resources and interspecific competition, which are lower in the dry season, seem to be responsible for the shifts in space use observed for G. microtarsus males. We recommend studies with spool-and-line techniques or radio tracking to further test refined hypotheses regarding the use of space, including the role of territoriality in females.

ECOLOGICAL MODELING OF TALITROIDES TOPITOTUM (CRUSTACEA: AMPHIPODA)

A compartmental model was developed to describe the temporal course of an exotic amphipod's population, Talitroides topitotum, in an Atlantic Forest habitat in Brazil. Extensive biological information — including breeding pattern, development and mortality rates, and temperature dependence of the parameters — were considered in the model. A genetic algorithm was used to estimate model parameters by comparing simulation results with field data. This allowed us to discuss the reproductive strategies adopted by this species and to analyze the potential influence of global climate changes on its populations dynamics.

A Remarkable New Glass Frog (Centrolenidae:Vitreorana) from the Northeast Atlantic Forest, Brazil

Abstract: We describe a new species of glass frog (Vitreorana) from Fazenda Novo Pau Brasil, in the Atlantic Forest habitat of northeastern Brazil. Previous to this work, Vitreorana baliomma sp. nov. was misidentified as V. eurygnatha, from which it can be distinguished by the iris pattern flecked with star-shape melanophores; rudimentary nuptial excrescences formed by glands on the dorsomedial surface of Finger I, with some accessorial glands along its periphery; parietal, urinary bladder, kidneys, and testes peritonea translucent; visceral peritoneum with iridophores covering the pericardium, liver, and gastrointestinal tract. We also provide a brief discussion on its morphological similarities with other Vitreorana species.

Woody Species Regeneration in Atlantic Forest Restoration Sites Depends on Surrounding Landscape

Both passive and active restoration are limited by diaspore arrival from neighboring sources. Surrounding landscape is thus important for restoration success in fragmented landscapes, where reforestation, for long periods, may be limited to the planted species pool. We sampled woody species regeneration in 17 reforestation sites in Southern Brazil to investigate the effects of distance to seed sources and amount of remaining nearby Atlantic Forest habitat. The abundance and species richness of regenerating plants were explained by multiple regressions performed using plantation age and species richness, distance to the nearest patch, and surrounding habitat. Distance to the nearest forest remnant, through both the matrix in a straight line and riparian vegetation, was the best predictor of species richness and abundance of regenerating plants. Riparian corridors doubled the distance at which forest remnants influenced restoration sites. However, the area of forest remnants in the site neighborhood did not influence regeneration diversity, suggesting that the quality of both the seed source (including the status of seed dispersing fauna) and reforestation environment for the establishment of forest species should be investigated.

Updates to the taxonomy of Swartzia (Leguminosae) in extra-Amazonian Brazil, with descriptions of five new species and a regional key to the genus

In advance of an updated monographic revision of Swartzia (Leguminosae), we discuss the taxonomy of the genus in extra-Amazonian Brazil and present descriptions of five new species. All of the new species are narrowly distributed in eastern Brazil in threatened Atlantic wet forest and coastal scrub habitats. Four of them—S. alagoensis, S. arenophila, S. revoluta, and S. submontana—belong to the diverse and taxonomically challenging section Acutifoliae, which has undergone extensive evolutionary radiation in the region. The fifth, S. thomasii, is a member of the otherwise Amazonian section Glabriplantae and is only subtly distinct from the Amazonian species S. reticulata. The new species and other recent additions to the genus are incorporated in a key to the species of Swartzia of extra-Amazonian Brazil.

The alarm call system of wild black-fronted titi monkeys, Callicebus nigrifrons

Upon encountering predators, many animals produce specific vocalisations that alert others and sometimes dissuade the predators from hunting. Callicebus monkeys are known for their large vocal repertoire, but little is known about the function and meaning of most call types. We recorded a large number of natural predator responses from five different groups of black-fronted titi monkeys in their Atlantic forest habitat in South Eastern Brazil. When detecting predatory threats, adult group members responded with call sequences that initially consisted of two brief, high-pitched calls with distinct frequency contours. Call A was mainly given to raptors but also to predatory capuchin monkeys and other threats within the canopy, while call B was given to predatory or non-predatory disturbances on the ground. In later parts of the sequences, we also recorded a high-pitched unmodulated call C and various low-pitched loud calls. Results therefore suggest that calls A and B provide listeners with rapid and reliable information about the general classes of danger experienced by the caller, while obtaining more specific information through other call types and combinations and behavioural responses. We discuss these findings in relation to current evolutionary theory of primate communication.

Intra‐community coalitionary lethal attack of an adult male southern muriqui (Brachyteles arachnoides)

We report on the first evidence of intra-community coalitionary lethal aggression in muriquis (Brachyteles). The event occurred in southern muriquis (Brachyteles arachnoides) during a long-term study (>15 years) of two social groups inhabiting mostly pristine Atlantic forest habitat in the Parque Estadual Carlos Botelho, southern São Paulo State, Brazil. The attack took place deep in the core area of the Group Caetê home range. Tense agonistic behaviors and vocalizations preceded the lethal coalitionary attack, and the tension increased over a 36-48 hr period. One adult female and two unidentified individuals also took part in a coalition led by six adult males. The members of the coalition collectively approached, embraced, immobilized and repeatedly bit the entire body of an adult male, resulting in severe bleeding injuries and the victim's death in less than 1 hr after the attack commenced. Combined ecological, behavioral and spatial data related to the event indicate that this was an intra-community attack and suggest social tensions related to mating competition as the proximate trigger of the coalitionary killing. The attack resembled those reported for chimpanzees, with clear numeric superiority and a low risk of injury to aggressors, resulting in the death of a lone conspecific victim. This observation (n=1) is suggestive of a capacity for escalated aggression in muriquis and reinforces arguments for the potential adaptive significance of intra-community aggression in male philopatric societies, as reported for spider monkeys and chimpanzees. These characteristics challenge the view of the muriquis as a peaceful primate and support the general hypothesis that imbalances of power contribute to intra-specific killing in primates, such as chimpanzees and humans.

Composition and natural history of a Cerrado snake assemblage at Itirapina, São Paulo state, southeastern Brazil

Neotropical snake assemblages present high species richness and complex structures. The Cerrado is the second largest biome in Brazil, and was included among the 25 World's biodiversity hotspots. In southeastern Brazil, the remnant Cerrado areas have suffered intense destruction, and presently less than 2% of Cerrado natural vegetation remain in São Paulo state. Virtually no detailed study on Cerrado snakes was carried out in this region. The Itirapina region has one of the last well preserved remnants of open cerrado in São Paulo state. Our purpose in this work was the study of natural history and composition of the Cerrado snakes of Itirapina region. We performed an extensive field sampling combining six sampling methods in Estação Ecológica de Itirapina and disturbed Cerrado areas in its surroundings (municipalities of Itirapina and Brotas), during 101 trips throughout 43 months, between September 1998 and March 2002, corresponding to 446 days of field sampling. We also collected additional data from museum specimens housed in scientific collections. We present data on size, general abundance, habitat and macrohabitat use, daily and seasonal activity, feeding, reproduction, and defense. We also compared the Itirapina snake assemblage with nine snake assemblages of Brazil, from Amazonia, Atlantic Forest, Cerrado, and other open habitats. We recorded a total of 36 snake species among 755 individuals found in the field and six records from scientific collections and literature, belonging to 25 genera and five families. The snake assemblage comparisons indicate that the Cerrado has its own identity regarding the snake composition. Although small (about 2,300 ha), the Estação Ecológica de Itirapina encompasses well preserved and representative Cerrado physiognomic forms, which harbors a rich and typical Cerrado snake fauna. The occurrence of some species only inside the reserve also indicates that the Estação Ecológica de Itirapina is of fundamental importance to the maintenance of Cerrado biodiversity.