The distribution and abundance of small mammals in agroecosystems of southeastern Brazil

The conservation of biodiversity in agricultural landscapes depends on information about the ways in which species are affected by the conversion of native habitats into novel anthropogenic environments and the strategies that the species use to persist in these altered ecosystems. Here, we investigate how small mammals occupy the different agroecosystems of an agricultural landscape in the state of Sao Paulo, Brazil. From August 2003 through January 2005, we surveyed small mammals using Sherman traps at 16 sampling sites in each of the four predominant environments of the local agricultural landscape: remnant fragments of semideciduous forest, Eucalyptus plantations, sugarcane plantations, and pastures. With a total effort of 23,040 trap-nights and a capture success of 0.8%, we captured 177 rodents and marsupials belonging to eight species. The assemblage represented by these mammals is essentially composed of generalist species, which are common in degraded areas. Sugarcane plantations had the highest abundance, whereas pastures had the lowest species richness. Our results suggest that the loss of forest species can be related to the loss of native forest. The results also indicate that to improve the conservation value of agricultural landscapes, native forest fragments should be conserved, extensive monocultures should be avoided and agricultural impacts should be mitigated.

A Revision of Hortia (Rutaceae)

A taxonomic revision of the genus Hortia (Rutaceae) is presented. Hortia is a Neotropical genus with most of the species occurring in the Amazonian region. The species are woody, nearly all trees, with simple leaves crowded near the apices of the branches, showy broad corymbose terminal inflorescences, reddish to pink flowers, and berries with abundant oil glands. Ten species are recognized here, most of them occurring in Brazil. A key to the species, descriptions, synonyms, illustrations, as (yell as comments on the geographic distribution, ecology, and economic uses of each species are presented.

Cryptic Species of the Anastrepha fraterculus Complex (Diptera: Tephritidae): A Multivariate Approach for the Recognition of South American Morphotypes

Although a large amount of data have been published in past years on the taxonomic status of the Anastrepha fraterculus (Wiedemann) species complex, there is still a need to know how many species this complex comprises, the distribution of each one, and their distinguishing features. In this study, we assessed the morphometric variability of 32 populations from the A. fraterculus complex, located in major biogeographical areas from the Neotropics. Multivariate techniques for analysis were applied to the measurements of 21 variables referring to the mesonotum, aculeus, and wing. For the first time, our results identified the presence of seven distinct morphotypes within this species complex. According to the biogeographical areas, populations occurring in the Mesoamerican dominion (Mexico, Guatemala, and Panama) were clustered within a single natural entity labeled as the "Mexican" morphotype; whereas in the northwestern South American dominion, samples fell into three distinct groups: the "Venezuelan" morphotype with a single population from the Caribbean lowlands of Venezuela, the "Andean" morphotype from the highlands of Venezuela and Colombia, and the third group or "Peruvian" morphotype comprised the samples from the Pacific coastal lowlands of Ecuador and Peru. Three additional groups were identified from the Chacoan and Paranaense sub-regions: the morphotype "Brazilian-1" was recognized as including the Argentinean samples with most pertaining to Brazil, and widely distributed in these biogeographical areas; the morphotype "Brazilian-2" was recognized as including two samples from the state of Sao Paulo (Ilha-Bela and Sao Sebastiao); whereas the morphotype "Brazilian-3" included a single population from Botucatu (state of Sao Paulo). Based on data published by previous authors showing genetic and karyotypic differentiation, as well as reproductive isolation, we have concluded that such morphotypes indeed represent natural groups and distinct taxonomic entities.

First assessment of the endoparasitic nematode fauna of four psammophilous species of Tropiduridae (Squamata: Iguania) endemic to north-eastern Brazil

Tropiduridae (Squamata: Iguania) is a lizard taxon widely distributed in the neotropics. Among its representatives, some species are classified as generalists regarding habitat usage. Others exhibit a very restricted and probably relict distribution, and are strongly associated with predominantly sandy and dry habitats. Within this rather ecologically similar than phylogenetically closely related group we examined specimens of Eurolophosaurus amathites, E. divaricatus, Tropidurus hygomi, T. psammonastes for endoparasites. In all four species examined we recorded parasitic nematodes (Nemathelminthes: Nematoda). At least three nematode species were recovered: Parapharyngodon sp., Physaloptera lutzi and Strongyluris oscari, with Ph. lutzi being the most abundant parasite encountered in all lizard species examined. In spite of the hosts' habitat specialization, these parasites are also found frequently in non-psammophilous tropidurid species as well as in other squamates. Individual species richness per lizard was low, with usually just one species parasitizing at a time. These are the first parasites registered for these tropidurids and constitute a total of six new host records.

Sodium-specific foraging by leafcutter ant workers (Atta cephalotes, Hymenoptera: Formicidae)

1. Sodium is often a limiting nutrient for terrestrial animals, and may be especially sought by herbivores. Leafcutter ants are dominant herbivores in the Neotropics, and leafcutter foraging may be affected by nutritional demands of the colony and/or the demands of their symbiotic fungal mutualists. We hypothesized that leafcutter colonies are sodium limited, and that leafcutter ants will therefore forage specifically for sodium. 2. Previous studies demonstrated that leafcutter Atta cephalotes Linnaeus workers preferentially cut and remove paper baits treated with NaCl relative to water control baits. Atta cephalotes colonies in this study were presented with baits offering NaCl, Na2SO4, and KCl to test whether leafcutters forage specifically for sodium. Sucrose and water were used as positive and negative controls, respectively. 3. Atta foragers removed significantly more of the baits treated with NaCl and Na2SO4 than the KCl treatment, which did not differ from water. The NaCl and Na2SO4 treatments were collected at similar rates. We conclude A. cephalotes forage specifically for sodium rather than for anions (chloride) or solutes in general. This study supports the hypothesis that leafcutter ants are limited by, and preferentially forage for, sodium.

Craniometric diversity of the common vampire bat (Desmodus rotundus) in Central and South America

The common vampire bat, Desmodus rotundus Geoffroy, 1810, is a species with an extensive geographical distribution, occurring in a wide variety of habitats. A recent phylogeographical study using molecular markers described a scenario in which this species is formed by 5 distinct geographically circumscribed mitochondrial clacks. Here we studied the craniometric variation of the common vampire bat to assess the amount of subdivision within this species and to test for the possibility of distinct morphological patterns associated with geographical lineages. We used 16 measurements from 1,581 complete skulls of adult D. rotundus representing 226 localities in South America and Mesoamerica. The assessment of morphological diversity between groups was done by the estimation of minimum F-ST values. Overall, the results show that most of the within-species variation is a result of the size component. Both shape data and size data are correlated with geographic distances. Our results favor the origin of biological diversity as the outcome of genetic drift and stepping-stone pattern of gene flow instead of local adaptations to local environmental conditions. The F-ST analyses also support male-biased dispersal. The results give little evidence to support previous suggestions that the common vampire bat may be composed of 2 or more species.

Polyphyly of the hawk genera Leucopternis and Buteogallus (Aves, Accipitridae): multiple habitat shifts during the Neotropical buteonine diversification

Abstract Background The family Accipitridae (hawks, eagles and Old World vultures) represents a large radiation of predatory birds with an almost global distribution, although most species of this family occur in the Neotropics. Despite great morphological and ecological diversity, the evolutionary relationships in the family have been poorly explored at all taxonomic levels. Using sequences from four mitochondrial genes (12S, ATP8, ATP6, and ND6), we reconstructed the phylogeny of the Neotropical forest hawk genus Leucopternis and most of the allied genera of Neotropical buteonines. Our goals were to infer the evolutionary relationships among species of Leucopternis, estimate their relationships to other buteonine genera, evaluate the phylogenetic significance of the white and black plumage patterns common to most Leucopternis species, and assess general patterns of diversification of the group with respect to species' affiliations with Neotropical regions and habitats. Results Our molecular phylogeny for the genus Leucopternis and its allies disagrees sharply with traditional taxonomic arrangements for the group, and we present new hypotheses of relationships for a number of species. The mtDNA phylogenetic trees derived from analysis of the combined data posit a polyphyletic relationship among species of Leucopternis, Buteogallus and Buteo. Three highly supported clades containing Leucopternis species were recovered in our phylogenetic reconstructions. The first clade consisted of the sister pairs L. lacernulatus and Buteogallus meridionalis, and Buteogallus urubitinga and Harpyhaliaetus coronatus, in addition to L. schistaceus and L. plumbeus. The second clade included the sister pair Leucopternis albicollis and L. occidentalis as well as L. polionotus. The third lineage comprised the sister pair L. melanops and L. kuhli, in addition to L. semiplumbeus and Buteo buteo. According to our results, the white and black plumage patterns have evolved at least twice in the group. Furthermore, species found to the east and west of the Andes (cis-Andean and trans-Andean, respectively) are not reciprocally monophyletic, nor are forest and non-forest species. Conclusion The polyphyly of Leucopternis, Buteogallus and Buteo establishes a lack of concordance of current Accipitridae taxonomy with the mtDNA phylogeny for the group, and points to the need for further phylogenetic analysis at all taxonomic levels in the family as also suggested by other recent analyses. Habitat shifts, as well as cis- and trans-Andean disjunctions, took place more than once during buteonine diversification in the Neotropical region. Overemphasis of the black and white plumage patterns has led to questionable conclusions regarding the relationships of Leucopternis species, and suggests more generally that plumage characters should be used with considerable caution in the taxonomic evaluation of the Accipitridae.

Hunting practices among the Awá-Guajá: towards a long-term analysis of sustainability in an Amazonian indigenous community

Indigenous Reserves have played an indispensable role in maintaining forest areas in the Neotropics. In the Amazon there is a clear correlation between these reserves and the presence of forest cover; however, the simple presence of uninterrupted vegetation is no guarantee for the conservation of biodiversity, especially where hunting is practiced. This study describes hunting practices among the Awá-Guajá people from 1993 through 1994, also identifying sociocultural, technological, and demographic changes that have influenced their resource acquisition strategies over the last two decades. The data was obtained through ethnographic fieldwork, recording 78 days of foraging returns, with follow-up visits through 2010. This work provides useful information for an effective diachronic analysis of hunting in this community, by revealing foraging patterns of the early to mid-1990s, and describing community transformations over the last two decades in this locale.

A new species of Cryptocellus (Arachnida: Ricinulei) from Eastern Amazonia

Cryptocellus canga sp. nov. is described from specimens collected in several caves at Carajás National Forest, Pará, Brazil. The new species differs from other species of the genus by the morphology of copulatory apparatus of the male leg III.

Diversity versus disparity and the role of ecological opportunity in a continental bird radiation

Aim The Neotropical parrots (Arini) are an unusually diverse group which colonized South America in the Oligocene. The newly invaded Neotropics may have functioned as an underused adaptive zone and provided novel ecological opportunities that facilitated diversification. Alternatively, diversification may have been driven by ecological changes caused by Andean uplift and/or climate change from the Miocene onwards. Our aim was to find out whether Arini diversified in a classical adaptive radiation after their colonization of South America, or whether their diversification occurred later and was influenced by more recent environmental change. Location Neotropics. Methods We generated a time-calibrated phylogeny of more than 80% of all Arini species in order to analyse lineage diversification. This chronogram was also used as the basis for the reconstruction of morphological evolution within Arini using a multivariate ratio analysis of three size measurements. Results We found a concentration of size evolution and partitioning of size niches in the early history of Arini consistent with the process of adaptive radia- tion, but there were no signs of an early burst of speciation or a decrease in speci- ation rates through time. Although we detected no overall temporal shifts in diversification rates, we discovered two young, unexpectedly species-rich clades. Main conclusions Arini show signs of an early adaptive radiation, but we found no evidence of the slowdown in speciation rate generally considered a feature of island or lake radiations. Historical processes and environmental change from the Miocene onwards may have kept diversification rates roughly constant ever since the colonization of the Neotropics. Thus, Arini may not yet have reached equilibrium diversity. The lack of diversity-dependent speciation might be a general feature of adaptive radiations on a continental scale, and diversification processes on continents might therefore not be as ecologically limited as in isolated lakes or on oceanic islands.

The ecoclimatology of Danum, Sabah, in the context of the world's rainforest regions, with particular reference to dry periods and their impact

Climatic records for Danum for 1985 to 1998, elsewhere in Sabah since 1879, and long monthly rainfall series from other rainforest locations are used to place the climate, and particularly the dry period climatology, of Danum into a world rainforest context. The magnitude frequency and seasonality of dry periods are shown to vary greatly within the world's rainforest zone. The climate of Danum, which is aseasonal but subject, as in 1997 to 1998, to occasional drought, is intermediate between less drought–prone north–western Borneo and the more drought–prone east coast. Changes through time in drought magnitude frequency in Sabah and rainforest locations elsewhere in South–East Asia and in the Neotropics are compared. The 1997 to 1998 ENSO–related drought event in Sabah is placed into a historical context. The effects of drought on tree growth and mortality in the tropics are assessed and a model relating intensity and frequency of drought disturbance to forest structure and composition is discussed.

Sistemática de Sericothripinae (Thysanoptera, Thripidae) e revisão taxonômica das espécies neotropicais

Esta tese é dividida em duas partes: traçar a filogenia de Sericothripinae Karny, 1921 e realizar uma revisão taxonômica das espécies neotropicais. Para a análise filogenética, estados de caracteres morfológicos foram examinados entre Sericothripinae e Thysanoptera-Terebrantia relacionados, e as relações genéricas e supragenéricas foram exploradas. O monofiletismo de Sericothripinae foi recuperado, mas o formato do metasterno, usado na classificação dos gêneros, provavelmente não reflete a filogenia. De acordo com estudos moleculares recentes, o grupo genérico Scirtothrips em conjunto com o gênero Echinothrips Moulton, 1911 foram recuperados como intimamente relacionados aos Sericothripinae, mas, neste trabalho, Psilothrips Hood, 1927 e Pseudothrips Hinds, 1902 foram recuperados como não relacionados com Sericothripinae. Muitos estados de caracteres morfológicos entre os Sericothripinae são considerados homoplásticos e, na ausência de análises moleculares adequadas, alterações formais de nomenclatura não foram realizadas. Na revisão taxonômica, 14 novas espécies de Sericothripinae da região Neotropical são descritas. Chaves ilustradas foram elaboradas para as fêmeas de sete espécies de Hydatothrips Karny, 1913 e 41 espécies de Neohydatothrips John, 1929, principalmente do Brasil, mas incluindo todas as espécies registradas do sul da fronteira entre o México e os EUA até o extremo sul da América do Sul. Espécies de plantas em que associações-hospedeiras foram registradas são indicadas sempre que possível, comentários são elencados para as poucas espécies de importância econômica e uma chave para imaturos de segundo instar de cinco espécies é proposta. Neohydatothrips burungae (Hood, 1935) stat. rev. e N. aztecus Johansen, 1983 stat. rev. são retiradas de sinonímia com N. signifer (Priesner, 1932), ao passo que Sericothrips denigratus De Santis, 1966 syn. n. é sinonimizada com N. burungae. Hydatothrips williamsi (Hood, 1928) comb. n. é realocado de Neohydatothrips e, com isso, houve um caso de homônimo no gênero. Para resolver esse problema, H. tareei nom. nov. é proposto para H. williamsi Mound e Tree, 2009, da Austrália.

Revisão taxonômica de Octostruma Forel, 1912 (Formicidae, Myrmicinae)

O gênero de formigas Octostruma Forel 1912 (Formicidae: Myrmicinae) está restrito à região Neotropical; suas espécies ocorrem do México até a Argentina, são predadoras de pequenos artrópodes e podem nidificar no solo, serapilheira e em epífitas. No presente trabalho, a taxonomia do gênero é revista com base no exame de cerca de 4.000 exemplares. Reconheço 43 espécies de Octostruma, 34 espécies previamente conhecidas são consideradas válidas e redescritas e, portanto, nove são reconhecidas como novas. Além disso, indivíduos de castas e sexos ainda não registrados (machos, gines e ergatóides) são aqui descritos pela primeira vez para diferentes espécies. Novos registros de localidades expandem a distribuição geográfica conhecida para parte das espécies e informações sobre a biologia das espécies a partir de dados de rótulo e observações de campo, somados às poucas informações encontradas na literatura são compiladas neste trabalho. Uma chave de identificação para as operárias de todas as espécies do gênero é fornecida.

Enigmatic faunal declines at La Selva, Costa Rica: Patterns and processes in a collapsing neotropical herpetofauna

Amphibian populations are declining even in pristine areas in many parts of the world, and in the Neotropics most such enigmatic amphibian declines have occurred in mid- to high-elevation sites. However, amphibian populations have also declined at La Selva Biological Station in the lowlands of Costa Rica, and similar declines in populations of lizards have occurred at the site as well. To set the stage for describing amphibian declines at La Selva, I thoroughly review knowledge of amphibian decline and amphibian conservation in Central America: I describe general patterns in biodiversity, evaluate major patterns in and ecological correlates of threat status, review trends in basic and applied conservation literature, and recommend directions for future research. I then synthesize data on population densities of amphibians, as well as ecologically similar reptiles, over a 35-year periods using quantitative datasets from a range of studies. This synthesis identifies assemblage-wide declines of approximately 75% for both amphibians and reptiles between 1970 and 2005. Because these declines defy patterns most commonly reported in the Neotropics, it is difficult to assess causality evoking known processes associated with enigmatic decline events. I conduct a 12-month pathogen surveillance program to evaluate infection of frogs by the amphibian chytrid fungus, an emerging pathogen linked to decline events worldwide Although lowland forests are generally believed to be too warm for presence or adverse population effects of chytridiomycosis, I present evidence for seasonal patterns in infection prevalence with highest prevalence in the coolest parts of the year. Finally, I conducted a 16-month field experiment to explore the role of changes to dynamics of leaf litter, a critical resource for both frogs and lizards. Population responses by frogs and lizards indicate that litter regulates population densities of frogs and lizards, particularly those species with the highest decline rate. My work illustrates that sites that are assumed to be pristine are likely impacted by a variety of novel stressors, and that even fauna within protected areas may be suffering unexpected declines.

Leaf Gas Exchange and Nutrient Use Efficiency Help Explain the Distribution of Two Neotropical Mangroves under Contrasting Flooding and Salinity

Rhizophora mangle and Laguncularia racemosa cooccur along many intertidal floodplains in the Neotropics. Their patterns of dominance shift along various gradients, coincident with salinity, soil fertility, and tidal flooding. We used leaf gas exchange metrics to investigate the strategies of these two species in mixed culture to simulate competition under different salinity concentrations and hydroperiods. Semidiurnal tidal and permanent flooding hydroperiods at two constant salinity regimes (10 g L−1 and 40 g L−1) were simulated over 10 months. Assimilation ( ), stomatal conductance ( ), intercellular CO2 concentration ( ), instantaneous photosynthetic water use efficiency (PWUE), and photosynthetic nitrogen use efficiency (PNUE) were determined at the leaf level for both species over two time periods. Rhizophora mangle had significantly higher PWUE than did L. racemosa seedlings at low salinities; however, L. racemosa had higher PNUE and and, accordingly, had greater intercellular CO2 (calculated) during measurements. Both species maintained similar capacities for A at 10 and 40 g L−1 salinity and during both permanent and tidal hydroperiod treatments. Hydroperiod alone had no detectable effect on leaf gas exchange. However, PWUE increased and PNUE decreased for both species at 40 g L−1 salinity compared to 10 g L−1. At 40 g L−1 salinity, PNUE was higher for L. racemosa than R. mangle with tidal flooding. These treatments indicated that salinity influences gas exchange efficiency, might affect how gases are apportioned intercellularly, and accentuates different strategies for distributing leaf nitrogen to photosynthesis for these two species while growing competitively.