Neotropical Forests Research Articles

Poison in the nursery: Mercury contamination in the tadpole-rearing sites of an Amazonian frog

Artisanal and small-scale gold mining (ASGM) has become a major threat for Neotropical forests. This technique for obtaining gold is a substantial driver of small-scale deforestation and the largest contributor of Hg emissions to both the atmosphere and freshwater systems globally. Previous studies have demonstrated the impacts of Hg accumulation on various aquatic ecosystems and organisms. However, its consequences in other, more discrete systems such as phytotelmata (water-holding plant structures), and the organisms therein, have so far gone unnoticed. Here, we show high concentrations of Hg (mean ± SD: 1.43 ± 2.19 ppm) in phytotelmata and other small pools, the aquatic microenvironments used by the Neotropical poison frog Dendrobates tinctorius as tadpole-rearing sites. In 17 % of the cases, we detected Hg concentrations above the severe effect level (SEL = 2 ppm) for freshwater sediments. Hg concentrations varied depending on pool characteristics and tended to increase in proximity to known ASGM sites. We did not find an effect of Hg concentration on the number of D. tinctorius tadpoles in a given pool. Tadpoles were found in pools with concentrations of up to 8.68 ppm, suggesting that D. tinctorius fathers do not avoid pools with high Hg levels for tadpole deposition. While further research is needed to determine the potential effects of Hg on tadpole development, we found an intriguing tendency for tadpoles in later developmental stages to have lower body condition when occurring in pools with higher Hg concentrations. Our findings provide evidence of relevant Hg concentrations in the terrestrial water systems used by phytotelm-breeding anurans, and highlight the need of further field and experimental studies investigating the implications of Hg contamination for tadpole development and behaviour and the overall conservation of Amazonian biodiversity.

Paleomodeling reveals priority areas for conservation of stingless bees from the Caatinga region, a neotropical dry forest

Paleomodeling reveals priority areas for conservation of stingless bees from the Caatinga region, a neotropical dry forest

Determinants of the Vertical Distribution of the Phyllosphere Differ Between Microbial Groups and the Epi- and Endosphere in a Tropical Forest

The determinants of phyllosphere microbial communities are drawing much attention given their functional importance for their plant host fitness and health. Identifying these determinants remains challenging in neotropical forests, considering the diversity of the tree hosts and the strong vertical heterogeneity of abiotic conditions within the canopy and at the scale of the leaf. Here, we studied fungal and bacterial communities living in the endophytic and epiphytic phyllosphere in tree species across vertical gradients, from the top of the canopy to the ground. We used DNA metabarcoding to characterize microbial communities and measured abiotic variables and foliar traits to characterize environmental heterogeneity. The assembly of fungal communities was more driven by deterministic processes compared with bacteria, with endo- and epiphytic communities being similarly shaped by the host identity and unmeasured parameters. In contrast, in bacterial communities, the relative importance of deterministic processes decreased from endophytic to epiphytic communities. Bacterial epi- and endophytic communities were partly and differently determined by the position within the canopy, the host identity, and leaf traits, suggesting an effect of the vertical gradient and a stronger selection in the inner tissues of the leaf than on its surface. The tree host exerts a selective pressure on microbial communities but the leaf as microhabitat also contributes significantly to the assembly of microbial communities. Discrepancies exist between fungi and bacteria that probably reflect different life-history traits and ecological strategies, emphasizing the need to study these communities jointly if we are to fully understand plant–phyllosphere interactions. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

The complete mitochondrial genome of the lowland paca (Cuniculus paca) and its phylogenetic relationship with other New World hystricognath rodents

The lowland paca (Cuniculus paca) is a nocturnal, widespread, and solitary large-sized rodent in the family Cuniculidae, and one of the most frequently hunted mammals in the Neotropical forests of Latin America. We assembled the first complete mitochondrial genome of lowland paca using three closely related hystricognath species as reference sequences. The mitochondrial genome is 16,770 basepairs (bp) in length, with similar characteristics of vertebrate mitochondrial genomes. We performed phylogenetic analyses using 26 mitochondrial genome of hystricognath species based on thirteen protein-coding genes. The result confirms the taxonomical placement among the New World hystricognath rodents with high support. The placement is consistent with previous phylogenetic studies based on individual mitochondrial and nuclear genes. The current study improves the phylogenic resolution of hystricognath rodents.

Differential utilization of surface and arboreal water bodies by birds and mammals in a seasonally dry Neotropical forest in southern Mexico.

Water availability significantly influences bird and mammal ecology in terrestrial ecosystems. However, our understanding of the role of water as a limiting resource for birds and mammals remains partial because most of the studies have focused on surface water bodies in desert and semi-desert ecosystems. This study assessed the use of two types of surface water bodies (waterholes and epikarst rock pools) and one arboreal (water-filled tree holes) by birds and mammals in the seasonally dry tropical forests of the Calakmul Biosphere Reserve in southern Mexico. We deployed camera traps in 23 waterholes, 22 rock pools, and 19 water-filled tree holes in this karstic region to record visits by small, medium, and large-bodied birds and mammals during the dry and rainy seasons. These cameras were set up for recording videos documenting when animals were making use of water for drinking, bathing, or both. We compared the species diversity and composition of bird and mammal assemblages using the different types of water bodies by calculating Hill numbers and conducting nonmetric multidimensional scaling (NMDS), indicator species, and contingency table analyses. There was a greater species richness of birds and mammals using surface water bodies than tree holes during both seasons. There were significant differences in species composition among bird assemblages using the different water bodies, but dominant species and diversity remained the same. Terrestrial and larger mammalian species preferentially used surface water bodies, whereas arboreal and scansorial small and medium mammals were more common in arboreal water bodies. These findings suggest that differences in water body characteristics might favor segregation in mammal activity. The different water bodies may act as alternative water sources for birds and complementary sources for mammals, potentially favoring species coexistence and increasing community resilience to environmental variation (e.g., fluctuations in water availability). Understanding how differences in water bodies favor species coexistence and community resilience is of great relevance from a basic ecological perspective but is also crucial for anticipating the effects that the increased demand for water by humans and climate change can have on wildlife viability.

Patterns of Diversity, Structure and Local Ecology of Arthropod-Pathogenic Fungi in the Amazonian Forest of Cusco and Madre de Dios Regions, Southern Peru

The ecological role and potential management of arthropod-pathogenic fungi (APF) in neotropical forests are of great importance, but they are still little studied. The present study achieves a first estimation of diversity patterns, structure and local ecology of APF in the Amazonian forests of the Cusco and Madre de Dios regions in southern Peru. We sampled 39 localities in five basins, examining 277 specimens, four families and 20 genera with 82 species (40% morphospecies). The most diverse families were Cordycipitaceae with 51 species and Ophiocordicipitaceae (22). Cusco obtained a greater diversity: four families, 18 genera and 58 morphospecies, with the Urubamba and Amarumayu basins having greater diversity (31 and 20 species); for the Madre de Dios basin, there was 28 species. In both regions, the richness values were corroborated by Fisher’s Alpha and Chao-1 indexes, the latter identifies Amarumayu and Araza with maximum values. The NMDS analysis showed a good pattern of separation of the two APF communities, although an important group was shared. Elevation was identified as the environmental variable with the strongest influence on diversity and structure. The dominance analysis identified Ophiocordyceps australis and Paraisaria amazonica as hyperdominant, due to their density and distribution. The local ecological patterns in Pongo de Qoñec show that the richness of entomopathogens is largely favored by low understory light, associated with pristine or little-impacted habitats. We conclude that this first approximation of the knowledge of the high diversity of APF in southern Peru is still insufficient, but it demonstrates the importance of their conservation and represents enormous potential for sustainable management.

Five new Camillea (Xylariales) species described from French Guiana

BackgroundThe genus Camillea was created in 1849 from collections made in French Guiana with eight species included. Numerous species assigned to Camillea were subsequently discovered, especially in the forests of the Amazon basin, but new discoveries have not been reported from French Guiana since 1849. Recent fieldwork in French Guiana has begun to fill this gap by identifying five new species, most of which were collected in the vicinity of Saül village.ResultsBased on macro- and micromorphological study of their stromata, including SEM images of ascospore wall ornamentation, five new species were recognized, including C. cribellum, C. heterostomoides, C. nitida, C. rogersii and C. saulensis. Cultures could be obtained for C. heterostomoides and C. rogersii, and ITS and LSU sequences were obtained for all of the five new species. Camillea heterostoma and its variety microspora were shown to be conspecific. Provisional molecular phylogenetic analyses support the possible reinstatement of Hypoxylon melanaspis, currently regarded as merely an applanate form of C. leprieurii.ConclusionThe current study is based on a relatively limited fieldwork in its duration and sampling area but was able to substantially increase the number of Camillea species known from French Guiana. This augurs an exceptional and still unknown diversity of the genus in this area and by extension in the adjacent neotropical forests.

The prey of the Harpy Eagle in its last reproductive refuges in the Atlantic Forest

The Harpy Eagle (Harpia harpyja) is threatened with extinction throughout its distribution in the neotropical forests. In the Atlantic Forest, deforestation has reduced the number of suitable habitats, with only a few remnant forest fragments hosting active nests; currently, the only known nests in this region are in the Central Atlantic Forest Ecological Corridor (CAFEC), in Brazil. Little is known about Harpy Eagle diets in this region, despite this information being essential for developing effective conservation strategies. We classified the composition, frequency, richness, ecological attributes, and conservation status of the species that make up the Harpy Eagle’s diet in its last refuges in the CAFEC. Between 2017 and 2021, we collected and analyzed 152 prey remains and 285 camera trap photographs from seven active nests. We identified at least 16 mammal species (96.7%), one parrot and other bird remains (3.3%). The Harpy Eagle’s diet consisted mainly of medium-sized arboreal, folivorous, frugivorous, and diurnal mammals. Five prey species are currently threatened with extinction at global, six at national and seven at regional levels. The majority of the diet consists of Sapajus robustus, which is threatened, and Bradypus variegatus, which is not threatened. In addition to the effects of habitat loss and hunting, the Harpy Eagle may also suffer from the decline in the populations of their prey in the Atlantic Forest.

Ground Fire Legacy Effects on Water-Dynamics of Volcanic Tropical Soils

The forest floor is a critical component in maintaining the life cycles of forest ecosystems. It normally includes organic soil horizons, known as duff and litter, which are prone to be rapidly consumed after flaming and smoldering fires. This work aims to understand the legacy effects of surface and ground fires on the infiltration capacity of a volcanic forest soil. We studied five sites with fires recorded in the last 20 years. All of them are located in pine-oak forests of the volcanic mountain region in central Mexico with a temperate climate and Andic soil properties. Tension-infiltration tests were carried out to determine hydraulic conductivity and the number of active macropores. After each test, cores were taken to evaluate in a laboratory setting, where soil water repellency at different moisture concentrations and the integrative dynamic repellency index were determined. Field-saturated hydraulic conductivity was moderately high in all sites, with mean values of 13 and 42 mm·h−1 for burned and control plots, respectively. A non-linear relationship was found between recurrence and type of fires with the concentration of active pores and several dynamic water repellency parameters. This work confirmed the presence of latent combustion in these temperate neotropical forests. The changes in soil water repellency and hydraulic conductivity detected do not necessarily imply an exceeded soil infiltration capacity. However, many of the fires in this region are associated with increasing agricultural activities, so further studies are needed to determine if higher fire frequencies could exceed the resilience capacity of the soils triggering land degradation.

Functional traits of young seedlings predict trade‐offs in seedling performance in three neotropical forests

Abstract Understanding the mechanisms that promote the coexistence of hundreds of species over small areas in tropical forest remains a challenge. Many tropical tree species are presumed to be functionally equivalent shade tolerant species but exist on a continuum of performance trade‐offs between survival in shade and the ability to quickly grow in sunlight. These trade‐offs can promote coexistence by reducing fitness differences. Variation in plant functional traits related to resource acquisition is thought to predict variation in performance among species, perhaps explaining community assembly across habitats with gradients in resource availability. Many studies have found low predictive power, however, when linking trait measurements to species demographic rates. Seedlings face different challenges recruiting on the forest floor and may exhibit different traits and/or performance trade‐offs than older individuals face in the eventual adult niche. Seed mass is the typical proxy for seedling success, but species also differ in cotyledon strategy (reserve vs. photosynthetic) or other leaf, stem and root traits. These can cause species with the same average seed mass to have divergent performance in the same habitat. We combined long‐term studies of seedling dynamics with functional trait data collected at a standard life‐history stage in three diverse neotropical forests to ask whether variation in coordinated suites of traits predicts variation among species in demographic performance. Across hundreds of species in Ecuador, Panama and Puerto Rico, we found seedlings displayed correlated suites of leaf, stem, and root traits, which strongly correlated with seed mass and cotyledon strategy. Variation among species in seedling functional traits, seed mass, and cotyledon strategy were strong predictors of trade‐offs in seedling growth and survival. These results underscore the importance of matching the ontogenetic stage of the trait measurement to the stage of demographic dynamics. Our findings highlight the importance of cotyledon strategy in addition to seed mass as a key component of seed and seedling biology in tropical forests because of the contribution of carbon reserves in storage cotyledons to reducing mortality rates and explaining the growth‐survival trade‐off among species. Synthesis: With strikingly consistent patterns across three tropical forests, we find strong evidence for the promise of functional traits to provide mechanistic links between seedling form and demographic performance.

A Novel Isoprene Synthase from the Monocot Tree Copernicia prunifera (Arecaceae) Confers Enhanced Drought Tolerance in Transgenic Arabidopsis.

The capacity to emit isoprene, among other stresses, protects plants from drought, but the molecular mechanisms underlying this trait are only partly understood. The Arecaceae (palms) constitute a very interesting model system to test the involvement of isoprene in enhancing drought tolerance, as their high isoprene emissions may have contributed to make them hyperdominant in neotropical dry forests, characterized by recurrent and extended periods of drought stress. In this study we isolated and functionally characterized a novel isoprene synthase, the gene responsible for isoprene biosynthesis, from Copernicia prunifera, a palm from seasonally dry tropical forests. When overexpressed in the non-emitter Arabidopsis thaliana, CprISPS conferred significant levels of isoprene emission, together with enhanced tolerance to water limitation throughout plant growth and development, from germination to maturity. CprISPS overexpressors displayed higher germination, cotyledon/leaf greening, water usage efficiency, and survival than WT Arabidopsis under various types of water limitation. This increased drought tolerance was accompanied by a marked transcriptional up-regulation of both ABA-dependent and ABA-independent key drought response genes. Taken together, these results demonstrate the capacity of CprISPS to enhance drought tolerance in Arabidopsis and suggest that isoprene emission could have evolved in Arecaceae as an adaptive mechanism against drought.

Assessment of the Quality, Chemometric and Pollen Diversity of Apis mellifera Honey from Different Seasonal Harvests.

The parameters for assessing the quality of honey produced by Apis mellifera are standardized worldwide. The physicochemical properties of honey might vary extensively due to factors such as the geographical area where it was produced and the season in which it was harvested. Little information is available on variations in honey quality among different harvest periods in tropical areas, and particularly in neotropical dry forests. This study describes variations in seventeen physicochemical parameters and the pollen diversity of honey harvested from beehives during the dry season in February, March, and April 2021, in the dry arc of Panama. Potassium is the most abundant mineral in honey samples, and its concentration increases during the harvest period from February to April. A PCA analysis showed significant differences among the samples collected during different harvest periods. The pollen diversity also differs among honey samples from February compared with March and April. The results indicate that climatic conditions may play an important role in the quality of honey produced in the dry arc of Panama. Furthermore, these results might be useful for establishing quality-control parameters of bee honey produced in Panama in support of beekeeping activities in seasonal wet-dry areas of the tropics.

Long-and short-billed hummingbirds as pollinators of Palicourea demissa, a distylous treelet of Neotropical cloud forests.

Distyly has been interpreted as a mechanism that promotes cross-pollination between floral morphs. According to this hypothesis, pollen from anthers positioned at different heights could adhere to different body parts of the pollinator that would correspond to those points where stigmas of compatible morph contact the animal. In this regard, hummingbird species with different bill sizes may play different roles as pollinators of each morph. If pollinators mobilize more legitimate pollen towards one of the two morphs, gender specialization may occur. This work aimed to assess experimentally the role of long- and short-billed hummingbirds as pollinators of short-style (SS) and long-style (LS) flowers of Palicourea demissa, a distylous, hummingbird-pollinated treelet in Venezuelan cloud forests. Flowers were emasculated and exposed to a single visit of the hummingbird Coeligena torquata (long-billed), Heliangelus spencei (short-billed) or Adelomyia melanogenys (short-billed). Later, stigmas were removed, and pollen load counted under a microscope to calculate the probability of legitimate- and illegitimate-pollen transfer by hummingbirds. The probability analyses of pollen transference showed that short-billed hummingbirds have higher pollination probabilities from SS-anthers to LS- and SS-stigmas, and from LS-anther to LS-stigmas than from LS-anther to SS-stigmas. In contrast, long-billed hummingbirds have higher probabilities of pollen transference from LS-anthers to SS-stigmas than in other directions. A deeper view of the sexual expression of each morph in P. demissa will depend on future studies that determine possible morpho-differences in the biological function of male and female floral structures, and the role played by less frequent floral visitors as mediators of legitimate pollination between floral morphs.

Underestimated diversity and range size of diving beetles in tank bromeliads—Coleoptera of ‘hygrofloric’ lifestyle (Dytiscidae)

Abstract Tank bromeliads provide a vast amount of stagnant water high up in the Neotropical forest canopy. However, the aquatic macroinvertebrate diversity in this specialized habitat remains poorly explored. Here, we study obligatorily bromeliadicolous species of the diving beetle genus Copelatus Erichson, 1832. We review the known species Copelatus bromeliarum Scott, 1912 (Trinidad and Venezuela) and Copelatus bimaculatus Resende & Vanin, 1991 (Brazil). We describe three new species: Copelatus espinhasso sp. nov. (Brazil), Copelatus florae sp. nov. (Brazil, Colombia, Costa Rica, Ecuador and Panama) including its larva, and Copelatus panguana sp. nov. (Peru). Based on their male genital morphology, these species form a distinct clade within the genus. Other shared characters such as compact drop-shaped habitus, shortened appendages, and reduction of natatory setae on legs are interpreted as adaptations for what we call the ‘hygrofloric’ lifestyle. We document the thin water layer between leaf axils as the preferred habitat of both Copelatus adults and larvae, and not necessarily the central tank.

Evaluating factors affecting species detection using passive acoustic monitoring in neotropical forests: a playback experiment

ABSTRACT Passive acoustic monitoring (PAM) has become a popular approach for terrestrial species monitoring. Studies determining detection ranges and predictors of detection probability are needed for accurate ecological modelling based on PAM data. We conducted a playback experiment to evaluate factors affecting call detectability in a neotropical forest. We used Geoffroy´s spider monkeys as a model species and broadcast their contact calls at seven distances from autonomous recording units (ARUs) positioned at different heights, in forest patches of different ages, and controlled for climate conditions during broadcasting trials. Using GLMMs (N = 1,342 data points), we found that call detectability increased the smaller the difference between the ARU and speaker height. We further found detection range to be wider the younger a surveyed forest patch is. To test whether these effects were related to structural signal characteristics, we included vocalisations from seven sympatric species in the experiment (N = 9,394). We found peak frequency to modulate the effect of ARU height difference, and peak frequency and bandwidth to modulate the effect of forest age on call detectability. Our study sheds light on factors influencing acoustic signal detectability and emphasises the need to consider climatic and habitat variables when designing PAM programmes.

Contribution to the taxonomic elucidation of the Geonoma maxima complex (Arecaceae) in Central Amazonia, Brazil

Geonoma maxima (Poit.) Kunth is an example of a species complex, among many others restricted to Neotropical rain forests, which contribute to their high species diversity. Using environmental, morphological, karyological, and molecular data, we aim to test the taxonomic circumscription of 3 of the 11 G. maxima subspecies defined in the latest taxonomic treatment. We evaluated 217 samples of G. maxima complex from Ducke Reserve in the state of Amazonas, Brazil. Environmental preferences were significant at the 0.1% level. Subspecies maxima occurred in the slope, subsp. chelidonura in the floodplain, and subsp. spixiana in the plateau. Leaf morphology and height were different for each subspecies, but not leaf anatomy. The karyotypes of subspp. c helidonura and maxima were symmetrical with 2 n = 28 chromosomes, 16 metacentric and 12 submetacentric. Molecular analysis revealed two groups, one comprised subspp. maxima and chelidonura, and the other formed exclusively by subsp. spixiana. At Ducke Reserve, it is clear that the three subspecies are easily recognizable morphologically and ecologically, and it is likely that they do not interbreed locally. However, if these subspecies are analyzed on a larger geographic scale, it may not be possible to separate them.

The relationships between dung beetles and monkeys in the Neotropical region

The relationship between dung beetles and arboreal mammals has been scarcely studied, and many of the reports refer to observations without a standardized methodology. The accelerated loss of tropical forests urges us to understand this mutualistic association. Using our studies on arboreal dung beetles in the Palenque Archaeological Zone-National Park, Mexico, as a baseline, we analyzed the information on arboreal dung beetles in Neotropical forests in Mexico and around the world. Canthon euryscelis Bates, 1867, Canthon angustatus Harold, 1867, Canthon subhyalinus Harold, 1867, and Canthon femoralis (Chevrolat, 1834) are the main species collected in trees of Palenque, Onthophagus maya Zunino, 1981 and other non-Scarabaeinae species were occasionally collected from trees in Palenque. The small Canthon species are skilled fliers strongly relationship with monkeys in Palenque and other tropical regions of Mexico and Central America. In South America, arboreal dung beetles are more diverse and include these and other dung beetle species associated with monkeys. Several dung beetle species of the genus Onthophagus have been reported in association with African monkeys. In India, several studies report a wide variety of dung beetle species associated with monkeys. In Australia and New Guinea, only some species of Macropocopris are described as being associated with arboreal marsupials, but in Borneo, several dung beetle species have been observed associated with arboreal marsupials, mostly in managed forests. In Madagascar, Arachnoides gandi is the only beetle species reported in trees. We need to formulate a systematic and comparative methodology to understand better how arboreal beetles search for food, where the food is located, and how brood balls are made, how male-female pairs meet and nest, and how they contribute to arboreal dung recycling.

Timber yield of commercial tree species in the eastern Brazilian Amazon based on 33 years of inventory data

Abstract Selective logging in neotropical forests has directly affected the dynamics of tree species, compromising species conservation and timber yield. Sustainable use of logged forests requires new tree recruitment and diameter growth in remaining trees to compensate for trees removed between cutting cycles. This long-term study investigated timber yields in four species groups with differing values (lower, intermediate, high, and mixed) in logged and unlogged forests in the plateau region of the Tapajós River in the eastern Brazilian Amazon. Analysis was based on two size classes: medium and large commercial-sized trees. In both forest types (logged and unlogged), we found relevant tree recruitment and changes in size classes for all value groups. Most of the recruited trees observed during the 33 years of monitoring remained in the medium size class, but they also occurred in the large size class in logged forests. Over the same period, a significant loss of timber yield was seen, resulting from high mortality among the remaining trees in both size classes due to natural processes and the aftereffects of logging. Timber yield was also seen to be influenced by species richness within the group of commercial species, and recruitment and tree diameter growth capacity to counterbalance losses from mortality of the remaining trees after logging had become restricted. Forest timber yield was mainly regulated by light-demanding species, and shade-tolerant species contributed little to timber yield during the first cut. Continuous monitoring of the remaining trees and measures to reduce tree mortality during cutting cycles can encourage growth and reduce losses in stocked trees. Additionally, the national rules for forest management in the Brazilian Amazon need to be improved to achieve long-term management sustainability.

Similar survival of birds between wet and seasonally dry Neotropical environments

Studies in the tropics suggest a regional similarity in survival rates of adult birds; however, this literature often overlooks species in semi‐arid tropical environments. Bird survival in seasonally dry environments (e.g. seasonally dry tropical forests (SDTFa)) may be lower than that in more constantly wet areas (e.g. tropical rainforests (TRFs)), especially if the birds are negatively affected by seasonal rainfall or food‐limitation. However, survival could be similar across these tropical environments, as the asymmetry between young and adult mortality tends to be high in all tropical areas, and the higher risk of mortality in young animals may favour adult survival (residual reproductive investment) regardless of the local climatic conditions. To fill this knowledge gap, we tested the hypothesis that bird survival is similar between seasonally dry (SDTF) and constantly wet (TRF) Neotropical environments. We estimated the apparent survival of 27 South American bird populations from three SDTF areas and 39 populations from a TRF. Apparent survival was estimated from Cormack–Jolly–Seber (CJS) models fitted using a Bayesian structure and the resulting variation in survival rates between study areas and with body mass was explored using a Bayesian phylogenetic mixed model. Apparent annual survival of passerines did not differ between areas (geometrical mean of survival: SDTF = 0.50, 0.56, 0.64; TRF = 0.58), but body mass was positively associated with survival. The variation in bird survival was partially explained by phylogenetic relationships among species. Our results suggest that bird survival is regionally similar in Neotropical forests, despite the climatic variation. We discuss possible physiological and behavioural mechanisms adopted by birds in SDTFs to attenuate effects of environmental seasonality on survival.

Phylogenetic relationships and biogeography of the ancient genus Onychorhynchus (Aves: Onychorhynchidae) suggest cryptic Amazonian diversity

We examined phylogeographic patterns and cryptic diversity within the royal flycatcher, Onychorhynchus coronatus (Aves: Onychorhynchidae), a widespread Neotropical lowland forest tyrant flycatcher. A phylogeny of the six recognized subspecies was constructed from mtDNA sequence data of the NADH dehydrogenase subunit two gene, using Bayesian Inference and Maximum Likelihood methods. Phylogenetic analyses revealed high levels of intraspecific divergence within O. coronatus, supporting the existence of at least six independent lineages. The phylogenetic results uncovered the following relationships: (O. c. swainsoni [Southern Atlantic Forest], (O. c. coronatus [western Amazonia], (O. c. castelnaui [eastern Amazonia], (O. c. mexicanus [Central America], (O. c. occidentalis [Tumbesian], O. c. fraterculus [extreme northwestern South America])))). Biogeographic and dating analyses suggest that vicariant and dispersal events acted across approximately six million years to influence lineage diversification within this genus. Some of those events include the formation of the Amazon River and its tributaries, Andean uplift, and climatically induced vegetational shifts. Phylogenetic and biogeographic analyses of O. coronatus lineages support a hypothesis of area relationships in which the first divergence event isolated the Southern Atlantic Forest from Amazonia during the Late Miocene/Early Pliocene. This event was followed by the split of western and eastern Amazonia at the Early/Late Pliocene, the divergence of cis‐ and trans‐Andean lowland regions also at the Early/Late Pliocene, the split between Central America and the extreme northwestern South America/Tumbes at the Early/Middle Pleistocene, and the split between extreme northwestern South America and Tumbes at Middle/Late Pleistocene. Subsequent divergence of the southern and northern populations in the western and eastern Onychorhynchus lineages took place during the Pleistocene. Comparison of phylogenetic trees and patterns in Onychorhynchus with those from published work suggests that across large New World radiations such as the Suboscines, some co‐distributed lineages began to diverge long before others, which exemplifies the complexity of their evolutionary history.