Semi-arid Caatinga Research Articles

Diversity of nutcracking tool sites used by Sapajus libidinosus in Brazilian Cerrado.

Cracking nuts with tools is a behavior documented in a small number of populations of tufted capuchins, mainly in semi-arid Caatinga and Caatinga-Cerrado transitional environments of northeastern Brazil. Only one of these populations inhabits the less arid Cerrado in Central Brazil, where environments are composed of a heterogeneous mosaic of fields, savannas and forest formations. We conducted surveys in 10 of 20 localities where nutcracking by capuchins was reported by the local inhabitants in the Cerrrado of Northern Goiás and Tocantins. Our purpose was to evaluate nutcracking sites (anvils and associated hammers and nuts) based on indirect evidence of extensive pounding of nuts and seeds. Nutcracking was confirmed at all 10 surveyed localities. A total of 270 sites were identified. Surveyed localities included areas that were ecologically similar to those where capuchins crack nuts in Caatinga, as well as less arid localities with more typical Cerrado habitat. Anvils and hammers were made of materials including quartz, limestone, sandstone and wood, and displayed a wider range of sizes (i.e., 60-3,750 g for hammers' weight) than reported at previously studied localities. Nuts of seven genera were found in association with anvils and hammers. We conclude that nutcracking by capuchins are not restricted to arid environments and argue that the occurrence and diversity of nutcracking tool sites result from complex interactions of environmental variables (e.g., availability of food and mineral resources, density of canopy cover) and social variables (e.g., spatial cohesiveness and tolerance among group members) that need to be examined through long-term research of habituated groups. Localities in the Cerrado of Northern Goiás and Tocantins vary considerable in the ecological conditions faced by wild groups, and therefore offer the opportunity to examine these interactions.

Climatic Variables Do Not Directly Predict Spider Richness and Abundance in Semiarid Caatinga Vegetation, Brazil.

Spiders are abundant in tropical ecosystems and exert predatory pressure on a wide variety of invertebrate populations and also serve as prey for many others organisms, being part of complex interrelationships influenced directly and indirectly by a myriad of factors. We examined the influence of biotic (i.e., prey availability) and abiotic (i.e., temperature, precipitation, relative humidity, real evapotranspiration) factors on species richness and abundance during a two-year period in the semiarid Caatinga vegetation in northeastern Brazil. Data were analyzed through partial autocorrelation functions, cross correlations, and a path analysis. A total of 2522 spiders were collected with beating tray, pit-fall traps, and malaise traps, comprising 91 species and 34 families. Spider abundance peaked in the rainy season. Our results suggest that total invertebrate abundance has a direct influence on spider richness and abundance, whereas the effects of precipitation were mainly indirectly related to most spider assemblage parameters. The increase in vegetation cover with the rainy season in the Caatinga provides more breeding and foraging sites for spiders and stimulates their activities. Additionally, rainfall in arid and semiarid ecosystems stimulated the activity and reproduction of many herbivore and detritivore invertebrates dependent on plant biomass and necromass consumption, leading to an increase in spider prey availability.

A checklist of the fungi recorded from Serra da Jibóia, Bahia state, Brazil. 33 p.

Serra da Jibóia is one of the priority areas for the conservation of biodiversity located in the semiarid Caatinga biome of Northeast Brazil. Two hundred and fifty-nine species of fungi (mitosporic and meiosporic ascomycetes and basidiomycetes) were reported from Serra da Jibóia and are presented here. These species are distributed in 155 genera among which Dictyochaeta was the most highly represented genus with nine species. Inventory of the Serra da Jibóia region has thus far contributed to the description of one new genus and seven new species to science; six species are considered rare while 121 are new records of fungi. These data were based on literature records.

The influence of oceanic basins on drought and ecosystem dynamics in Northeast Brazil

The 2012 drought in Northeast Brazil was the harshest in decades, with potentially significant impacts on the vegetation of the unique semi-arid caatinga biome and on local livelihoods. Here, we use a coupled climate–vegetation model (CCM3-IBIS) to: (1) investigate the role of the Pacific and Atlantic oceans in the 2012 drought, and; (2) evaluate the response of the caatinga vegetation to the 2012 climate extreme. Our results indicate that anomalous sea surface temperatures (SSTs) in the Atlantic Ocean were the primary factor forcing the 2012 drought, with Pacific Ocean SST having a larger role in sustaining typical climatic conditions in the region. The drought strongly influenced net primary production in the caatinga, causing a reduction in annual net ecosystem exchange indicating a reduction in amount of CO2 released to the atmosphere.

Helminths infection patterns in a lizard (Tropidurus hispidus) population from a semiarid neotropical area: associations between female reproductive allocation and parasite loads.

This study reports helminth infection patterns of the lizard Tropidurus hispidus from an area of semiarid caatinga in northeastern Brazil (Ceará state). The lizard population was parasitized by 8 helminth species, and the species composition of the component community resembles that found for other Neotropical lizards. The prevalence of parasites was higher for males compared with females, whereas no relation was found between intensity of infection of 2 parasites (Parapharyngodon alvarengai and Physaloptera lutzi) and the lizards body size. For reproductive females, parasite infection intensity was negatively correlated to reproductive investment.

<I>Ypsilomyces</I>, a new thallic genus of conidial fungi from the semi-arid Caatinga biome of Brazil

<I>Ypsilomyces</I>, a new thallic genus of conidial fungi from the semi-arid Caatinga biome of Brazil

Taxonomic revision of Pseudorhopalia Wilcox & Papavero, 1971 (Insecta, Diptera, Mydidae, Rhopaliinae), with description of a new species from the Brazilian Amazon.

The previously monotypic genus Pseudorhopalia Wilcox & Papavero, 1971 is here revised, with description of a new species, Pseudorhopalia manauara, sp. n. The type-species, P. mirandai (d'Andretta & Carrera, 1951), is only found in northeastern Brazil, in the semiarid Caatinga biome. On the other hand, the new species is found in the humid Brazilian Amazonia, within dense ombrophilous forest and campina (scleromorphic scrub vegetation associated with white sand).

Parasitic nematodes of Polychrus acutirostris (Polychrotidae) in the Caatinga biome, Northeastern Brazil.

We present data on nematode infracommunity of the arboreal lizard Polycrhus acutirostris in the semiarid Caatinga biome, northeastern Brazil. Twenty- twolizard specimens collected in the municipality of Várzea Alegre in Ceará State and in the municipality of Exu in Pernambuco State were analyzed. Two species of nematodes were found, an Oxyuridae, Gynaecometra bahiensis, which had a mean intensity of infection 23.5 ± 5.8 (prevalence 22%) and a Physalopteridae, Physaloptera retusa which had infection intensity of 21 (prevalence 9%). There were no significant differences between the parasitism rates of male or female lizards. Polychrus acutirostris demonstrated low richness of nematode parasites, but high levels of infection with G. bahiensis. Polychrus acutirostrisis reported here as a new host for P. retusa.

Is there a bottom-up cascade on the assemblages of trees, arboreal insects and spiders in a semiarid Caatinga?

Predator–prey dynamics regulate the community structure of arthropods and may be affected by changes in their habitat. Bottom-up effects influence the distribution of arboreal insects changing, in turn, the availability of resources and shelter for the spider assemblage. This study examines the effect of habitat structure (tree richness and density) on the assemblages of herbivorous insects and spiders along a gradient of secondary forest succession in a semiarid Caatinga in northeastern Brazil. Insect and spiders were collected by beating the foliage during dry and wet seasons in 2010 and 2011. Plant richness and density varied significantly among stages of succession. In total, 2,590 arboreal insects were collected, corresponding to 14 orders and 151 morphospecies. In addition, we sampled 896 canopy spiders, encompassing 14 families and 53 morphospecies. Insect richness and abundance were negatively related with habitat structure, while spider richness increases with tree richness. We did not find any relationship among insects and spiders but there were differences in species composition of insects among all successional stages, determined by changes in vegetation structure. However, this effect does not extend to the species composition of spiders that remain similar in the different stages of secondary succession. We conclude that habitat structure had a partial bottom-up effect on arboreal insects and spider assemblages, indicating that this factor regulates the richness, abundance and species composition of arboreal insets and species richness of spiders. Thus, habitat structure promotes the maintenance of insects and spider diversity in fragments of Caatinga.

An Aromatic Volatile Attracts Oligolectic bee Pollinators in an Interdependent bee-Plant Relationship

Chemical signals emitted by the plant frequently mediate host-plant localization in specialized animal - plant associations. Studying the interdependent highly specialized association of the narrowly oligolectic bee pollinator Protodiscelis palpalis (Colletidae, Neopasiphaeinae) with Hydrocleys martii (Alismataceae) in ephemeral aquatic water bodies in semi-arid Caatinga of Brazil, we asked if specific volatile compounds produced by the flowers mediate pollinator attraction. The yellow Hydrocleys flowers are the sole pollen and nectar resources, and mating sites for the bees. We analyzed the floral scents of this species and of the closely related H. nymphoides, which is not visited by P. palpalis, and tested the main volatile compounds of both species under field conditions to evaluate their attractiveness to bees of P. palpalis. Methoxylated aromatics were the dominant floral scent components in both species, but each species exhibited a characteristic scent profile. Dual choice bioassays using artificial flowers made of yellow and blue adhesive paper clearly revealed that ρ-methylanisole alone, the dominant volatile of H. martii, attracted significantly more bees than unbaited flowers. This compound represents an olfactory communication channel used by the plant that lures its effective oligolectic pollinators to its flowers. Yellow artificial flowers baited significantly more bees than blue ones. Our study reinforces the recent findings that specific compounds in complex floral scent bouquets are crucial for host-plant location in oligolectic bees.

Diversity, natural history, and geographic distribution of snakes in the Caatinga, Northeastern Brazil

The present study is a synthesis on snake diversity and distribution in the Caatinga region of northeastern Brazil, providing an updated species list and data on natural history and geographic distribution. Our study is based on the careful revision of 7,102 voucher specimens, housed in 17 herpetological collections, complemented by data on taxonomic literature. We recorded a total of 112 snake species in the Caatinga, belonging to nine families: Anomalepididae, Leptotyphlopidae, Typhlopidae, Aniliidae, Boidae, Viperidae, Elapidae, Colubridae, and Dipsadidae. Our list includes at least 13 never recorded species for this region, as well as distribution records for all species known from the Caatinga (including expansion and new records of distribution). The snake assemblage of the Caatinga is complex, sharing species with other continental open areas (38.4%), forested areas (27.7%), and both open and forested areas (32.1%). The richest areas were isolated plateaus, followed by contact areas, semi-arid caatinga, and sandy dunes of the São Franscisco River. We identified 22 Caatinga endemic species with the sandy dunes of São Franscico River showing the highest endemism level (12 species, with six endemic species restricted to the area) followed by semi-arid caatinga, and isolated plateaus (eight endemic species each, and six and three endemic species with restricted distribution to each area, respectively). Most species show relatively restricted ranges in parts of the Caatinga. The snake assemblage in Caatinga includes mainly terrestrial species (38.4%), followed by fossorial/cryptozoic (26.8%), arboreal/semi-arboreal (26.8%), and aquatic/semi-aquatic (7.1%) species. Vertebrates are the most important dietary item (80.4%), with 56.6% of species being generalist consumers of this kind of prey; 24.4% are frog-eaters, 7.8% prey on caecilians/amphisbaenians, 6.7% lizard-eaters, 3.3% mammal-eaters, and 1.1% are fish-eaters. Only 18.7% of the snakes eat invertebrate prey, as arthropods, annelids, and mollusks. In relation to time of activity, 35.7% of snakes are both diurnal and nocturnal, 33.0% are strictly nocturnal, and 30.4% are diurnal. The data provided herein increase the list of Caatinga snake species from 50 to 112, and includes detailed maps and information on geographic distribution. The Caatinga snake assemblage shows high richness and endemism levels, and our results highlight the usefulness of basic natural history data and revision of voucher specimens as baseline information for biogeographic studies and conservation strategies.

Phylogeny and micro-habitats utilized by lizards determine the composition of their endoparasites in the semiarid Caatinga of Northeast Brazil.

Trophic networks can have architectonic configurations influenced by historical and ecological factors. The objective of this study was to analyze the architecture of networks between lizards, their endoparasites, diet, and micro-habitat, aiming to understand which factors exert an influence on the composition of the species of parasites. All networks showed a compartmentalized pattern. There was a positive relation between diet and the diversity of endoparasites. Our analyses also demonstrated that phylogeny and the use of micro-habitat influenced the composition of species of endoparasites and diet pattern of lizards. The principal factor that explained the modularity of the network was the foraging strategy, with segregation between the "active foragers" and "sit-and-wait" lizards. Our analyses also demonstrated that historical (phylogeny) and ecological factors (use of micro-habitat by the lizards) influenced the composition of parasite communities. These results corroborate other studies with ectoparasites, which indicate phylogeny and micro-habitat as determinants in the composition of parasitic fauna. The influence of phylogeny can be the result of coevolution between parasites and lizards in the Caatinga, and the influence of micro-habitat should be a result of adaptations of species of parasites to occupy the same categories of micro-habitats as hosts, thus favoring contagion.

The potential for large-scale wildlife corridors between protected areas in Brazil using the jaguar as a model species

Most large reserves in Brazil do not hold viable populations of jaguars to guarantee the species’ long-term survival. Corridors linking populations have been identified as a potential tool to avoid negative effects of isolation, increasing population viability. Here, we performed a Brazil-wide evaluation of potential large scale corridors connecting protected jaguar populations. Six variables (human population size, dam reservoir size, number of dams, roads, railways and cities) expected to negatively impact jaguar movement were analyzed across 180 potential corridors connecting 298 protected jaguar areas. We established overall disturbance scores for the corridors using a principal components analysis and compared them among the Brazilian biomes. We further investigated which variables separated biomes using a canonical variates analysis. The Atlantic Forest and the semi-arid Caatinga have the most impacted potential corridors, whereas the Amazon and Pantanal still have the best potential corridors. Corridor quality in the Cerrado grasslands was intermediate. All variables but human population size and corridor length contributed significantly to differences in corridor variables among biomes. Our conclusions suggest that we need to plan the implementation of large scale corridors in the Amazon, Pantanal and particularly the Cerrado soon, while potential corridors might still be economically viable. In the much more impacted Atlantic Forest and Caatinga, the need for conservation actions is strongest, but logistical difficulties and costs may turn implementation of corridors unfeasible.

Conidial fungi from the semiarid Caatinga biome of Brazil: a new species of Pseudoacrodictys

Conidial fungi from the semiarid Caatinga biome of Brazil: a new species of Pseudoacrodictys

New species and combinations of conidial fungi from the semi-arid Caatinga biome of Brazil

During a survey of conidial fungi carried out in aquatic and terrestrial habitats in the semi-arid Caatinga biome of Brazil, three new species were found on decaying plants. Anungitopsis caatingensis sp. nov. was found on decaying leaves collected in a terrestrial habitat. Codinaea pindobacuensis sp. nov. and Stanjehughesia clavata sp. nov. were found on decaying leaves and decaying bark collected in freshwater, respectively. Descriptions, illustrations and comments are presented, including a key to accepted species of Anungitopsis. Three species of Janetia are transferred to Linkosia and two species are proposed as synonyms: Minimelanolocus machili is synonymous with Cacumisporium pleuroconidiophorum and Janetia curviapicis is synonymous with Stanjehughesia hamatiella.

Monitoring jaguar populationsPanthera oncawith non-invasive genetics: a pilot study in Brazilian ecosystems

AbstractThe global population of jaguarsPanthera oncahas decreased significantly since the beginning of the 20th century. Given the scarcity of demographic and biological information, estimating population parameters is critical for the design of conservation measures. The jaguar's elusive behaviour makes it impossible to estimate and monitor populations by direct observation. We propose a non-invasive genetic sampling approach and demonstrate its potential for large-scale monitoring. Sex identification was optimized for faecal samples of jaguars and other felids. We also optimized a set of 11 microsatellite markers for reliable identification of individuals. We estimated the effectiveness of faecal sample genotyping in two distinct Brazilian biomes: the Pantanal and the semi-arid Caatinga. Almost 90% of the samples that were molecularly identified as jaguar (n = 90) were successfully genotyped and were assigned to 30 individuals. Genetic diversity was generally high but was significantly lower in the Caatinga population. We show that non-invasive genetic sampling can be a reliable tool to study population parameters and to monitor the genetic status of jaguar populations in different habitats. It may also be useful for future surveys of jaguars that address ecological, behavioural and conservation issues, and could provide a baseline for non-invasive genetic studies of other wild felid populations.

Behavioral adjustments by a small neotropical primate (Callithrix jacchus) in a semiarid Caatinga environment.

We provide the first information on the behavior of a small primate (Callithrix jacchus) inhabiting a semiarid Caatinga environment in northeastern Brazil. We observed behavioral variations in response to temperature fluctuation throughout the day. Due to the high temperatures, low precipitation, and resource scarcity in the Caatinga, as well as the lack of physiological adaptations (e.g., a highly concentrated urine and a carotid rete to cool down the brain) of these primates, we expected that the common marmosets would exhibit behavioral adjustments, such as a prolonged resting period or the use of a large home range. During the six-month period, we collected 246 hours of behavioral data of two groups (10 individuals) of Callithrix jacchus. Most of the observed behavioral patterns were influenced by temperature fluctuation. Animals rested longer and reduced other activities, such as foraging, when temperatures were higher. Both study groups exploited home ranges of 2.21–3.26 ha, which is within the range described for common marmosets inhabiting the Atlantic Forest. Our findings confirm that common marmosets inhabiting the Caatinga adjust their behavioral patterns to cope with the high temperatures that characterize this environment and highlight their ability to survive across a wide range of different environmental conditions.

Modeling a Virtual World for the Educational Game Calangos

Ecology plays a central role in biology and deserves special attention in scientific education. Nonetheless, the teaching and learning of ecology face a number of difficulties. In order to tackle these difficulties, electronic games have recently been used to mediate ecology learning. This paper presents an electronic game that fulfills these gaps in order to make the students’ work with ecological concepts more concrete, active, and systematic. The paper presents the computational model of the ecological system included in the game, based on a real ecological case, a sand dune ecosystem located in the semiarid Caatinga biome, namely, the sand dunes of the middle São Francisco River, in the state of Bahia, Brazil. It includes various ecological relationships between endemic lizards and the physical environment, preys, predators, cospecifics, and plants. The engine of the game simulates the physical conditions of the ecosystem (dune topography and climate conditions with their circadian and circannual cycles), its biota (plant species and animal species), and ecological relationships (predator-prey encounters, cospecific relationships). We also present results from one classroom study of a teaching sequence structured around Calangos, which showed positive outcomes regarding high school students’ understanding of thermal regulation in ectothermic animals.

Temporal variations of Collembola (Arthropoda: Hexapoda) in the semiarid Caatinga in northeastern Brazil

The richness and abundance of Collembola species can be influenced by many biotic and abiotic factors, mainly humidity. The semiarid region of Brazil is dominated by Caatinga dryland vegetation which experiences distinct seasonal alterations of its physiognomy linked to regional rainfall regimes. The present study evaluated the environmental factors affecting populations of Collembola in an area of Caatinga vegetation in Northeastern Brazil during a 12-months period. Specimens were collected by active searching in ten 20 x 20 m plots, with a sampling effort of 1 hour/person/plot. A total of 1231 specimens were collected, comprising 15 morphospecies, 12 genera, and nine families. Both species richness and individual abundances demonstrated oscillations during the year, with the highest values occurring during the rainy season; rainfall was the principal predictive variable for the observed temporal oscillations. Minimum temperatures and precipitation influenced the structural composition of the Collembola. Populations of Collembola demonstrated clustered distribution during the year. The direct and indirect effects of precipitation on the quality of microhabitats and resource availability were apparently responsible for the numerical and compositional alterations of the Collembola fauna observed in the Caatinga site.

Scutellospora alterata, a new gigasporalean species from the semi-arid Caatinga biome in Northeastern Brazil

A new species of Gigasporales (Glomeromycota) was isolated from soils of the semi-arid Caatinga biome in NE Brazil. It produced spores in the rhizospheres of Sorghum sudanense, Zea mays, Panicum maximum, and Helianthus annuus in pot cultures. Spores are triple-walled, roughened, yellow-white to light yellow, and 150–255 μm in diameter. The single germination shield is hyaline, oval to ovoid, and bi-lobed and has the two germ tube initiations (gtis) typical for Scutellospora species. The shields can change shape under light pressure on the cover slide, causing several 'false' lobes to appear that do not bear gtis but inflate from the shield periphery. Molecular analyses of the partial LSU rDNA gene place the fungus in a clade next to Scutellospora calospora, S. dipurpurescens, and S. spinosissima. Further investigations on germ shield morphology showed that several false lobes also form in other Scutellospora species in lactic acid based mountants under pressure on the cover slide. In Racocetraceae more than two 'true' lobes form during spore formation, each potentially bearing one gti.