Morphological abnormalities in a blue shark Prionace glauca (Chondrichthyes: Carcharhinidae) foetus from southern Brazil

This study records the occurrence of a blue shark Prionace glauca foetus, with morphological abnormalities in the trunk and cephalic region, from a female caught by a pelagic longline in October 2003, in southern Brazil.     

Restricted responsiveness to noise interference in two anurans from the southern temperate forest

Animals adopt different strategies to communicate by means of sound in noisy environments such that some species increase, while others decrease their vocal activity in the presence of interference. Anuran amphibians from diverse latitudes exhibit both kinds of responses. Recent studies have shown that males of Batrachyla taeniata and Batrachyla antartandica from the temperate austral forest do not call in response to the presentation of advertisement calls of sympatric congeneric species. In contrast, Batrachyla leptopus responds to these signals in a similar way as to conspecific calls. The responsiveness of B. taeniata to natural abiotic interference has also been tested and found that noises of such sources produce strong increases in vocal activity. To assess the diversity in responsiveness to acoustic intrusion in this group, we exposed males of B. leptopus and B. antartandica to prolonged pre‐recorded natural abiotic noises of wind, creek, rain, and to a band‐pass noise centered at 2,000 Hz, at 67 dB Sound Pressure Level (SPL). The subjects did not increase their vocal activity significantly when exposed to these sounds and to band‐pass noise at increasing intensities (55–79 dB SPL). These results contrast with the increase in vocal activity observed previously in B. taeniata to continuous abiotic noise and point to the existence of diverse strategies to confront acoustic intrusion among related species. The lack of vocal activation observed also contrasts with the responsiveness of B. leptopus to heterospecific signals, but parallels the lack of response to such sounds in B. antartandica. Furthermore, the results obtained contrast with the responsiveness of these species to synthetic prolonged sounds observed in previous studies, suggesting that the modes of responses to acoustic intrusion may depend on previous experience, rather than having a species‐specific nature.     

Cutaneous antipredatory secretions and pheromones in anurans and urodeles

The article analyses the main chemical signals used by anurans and urodeles for social interactions such as defence and reproduction. Some emblematic examples have been selected from the most significative reports. The antipredatory arsenal of many frogs and toads includes secretions of cutaneous glands, randomly distributed on the body or localised in “critical” skin regions. These substances act as repellent, alarm or venom, with specific toxicity and pharmacological actions. Other chemical cues facilitate social interactions. These “pheromones” allow animals to recognize conspecifics and to identify their sex, reproductive condition and social status. In many cases courtship pheromones play a crucial role in increasing male success. Evidence such as that suggests that selective pressures from environmental and social constraints produced the high incidence of chemical signalling typical of the amphibia, a view confirmed by the similarity of chemical cues across different taxa.     

Acoustic communities in an environmental gradient from native to urban areas in Central Brazil

As urban areas expand due to increasing human populations, natural habitats are diminishing in quantity and quality. We conducted a study to examine the response of diurnal acoustic communities along a gradient of environments, ranging from native to dense urban areas. We hypothesized that acoustic indices would decline with urbanization, transitioning from natural and rural areas to urban environments. We conducted the research in and around Brasília, Central Brazil. We deployed 24 digital recorders in native, rural, low-density and high-density urban areas. We employed five commonly used acoustic indices (ADI, ACI, NDSI, H and BI) to characterize the acoustic communities and represent the existing biodiversity numerically. We initially compared the index values across different land use types using a non-parametric rank sum test. Subsequently, we selected eight landscape metrics and performed a principal component analysis to summarize the surrounding matrix at each sampling point. We then employed generalized linear models to determine if the acoustic indices exhibited the anticipated variations. The results indicated significant variations in all indices among the different land use types, indicating their responsiveness to distinct acoustic communities and environmental characteristics. ADI, H and NDSI exhibited declining values from native to urban areas, while ACI and BI displayed the opposite trend. These findings underscore the influence of landscape structure on acoustic indices. Consequently, we concluded that adopting appropriate landscape planning, mainly through integrating natural and urban areas, could help preserve biodiversity in tropical urban regions.     

Plant endemism in two forests in southern Bahia, Brazil

An important factor in determining species rarity is the geographic distribution of species. Estimates were made of the level of endemism of the flora of two sites in the southern Bahian wet forest zone. Estimates were made for endemism in the Atlantic forest biome and for the much more restricted area of southern Bahia and northern Espi´rito Santo and are derived from analyses of the distributions of the species known from each area. The species checklist for each area is based on identified specimens resulting from intensive collecting in a forest near Serra Grande (40km north of Ilhe´us) and the Una Biological Reserve (40km south of Ilhe´us). Slightly less than half of the species (45.2% at Una and 47.7% at Serra Grande) have widespread distributions and 7.4% at each site are disjunct between the coastal forests and Amazonia. In the Una Reserve, 44.1% of the species are endemic to the coastal forest and 28.1% endemic to southern Bahia and northern Espi´rito Santo. At Serra Grande, 41.6% of the species are endemic to the coastal forest and 26.5% endemic to southern Bahia and northern Espi´rito Santo.     

Geographic variation of body size in New World anurans: energy and water in a balance

The validity of Bergmann's rule, perhaps the best known ecogeographical rule, has been questioned for ectothermic species. Here, we explore the interspecific version of the rule documenting body size gradients for anurans across the whole New World and evaluating which environmental variables best explain the observed patterns. We assembled a dataset of body sizes for 2761 anuran species of the Western Hemisphere and conducted assemblage‐based and cross‐species analyses that consider the spatial and phylogenetic structure in the data. In accordance with heat and water‐related explanations for body size clines, we found a consistent association of median body size and potential evapotranspiration across the New World. A relevant role of water availability also emerges, suggesting the joint importance of body size for thermoregulation and hydroregulation in anurans. Anurans do not follow a simple Bergmannian pattern of increasing size towards high latitudes. Consistent with previous regional findings, our Hemisphere‐wide analyses detect that the geographic variation in anuran body sizes is highly dependent on a trade‐off between heat and water balance. The observed size‐climate relationships possibly emerge from the interplay between thermoregulatory abilities and the benefits inherent to reduced surface‐to‐volume ratios in larger species, which decrease the rates of evaporative water loss and favour heat retention. Our results also show how temperature becomes important for species that are directly in contact with the substrate and water, like burrowing and terrestrial anurans, while arboreal species exhibit a body size cline linked with potential evapotranspiration.     

Potential damage by Acromyrmex ant species in pine plantations in southern Brazil

1. Acromyrmex species primarily attack Pinus taeda plantations during the first months after planting, with more intense damage in the first 30 days.
2. We evaluated potential damage by Acromyrmex crassispinus and Acromyrmex subterraneus in 30-day-old P. taeda plantations in southern Brazil by assessing the number of attacked plants and the distance reached by each colony, along with the losses in plant development resulting from different levels of defoliation.
3. Both species were significant pests in newly established pine plantations. A single colony can attack a substantial number of seedlings (up to 453 seedlings). Colonies with larger nests attacked more plants and ranged farther; A. crassispinus reached 59 m and A. subterraneus 87 m.
4. After 10 years, no significant losses in plant development were seen in seedlings defoliated less than 50% at 30 days after planting. But when defoliation of the young plants attained 75%, 100%, and 100%, including the cut of the apical meristem, volume losses reached 32%, 37%, and 43%, respectively.
5. Leaf-cutting ant controls should be carried out in plantations of P. taeda within 30 days of planting to avoid attacks. When seedlings are defoliated more than 75%, they should be replanted to avoid future losses in final wood volume.

     

Landscape mosaic of Araucaria forest and forest monocultures influencing understorey spider assemblages in southern Brazil

Abstract This study investigates how abundance, diversity and composition of understorey spiders were influenced by four different forest habitats in a southern Brazilian Araucaria forest. The study area encompasses a landscape mosaic comprised of Araucaria forest, Araucaria plantation, Pinus plantation, and Eucalyptus plantation. Understorey spiders were collected by beating the vegetation inside three patches of each forest habitat. To assess possible predictors of spider assemblage structure, several patch features were analysed: potential prey abundances, estimation of vegetation cover, diversity index of vegetation types, patch ages, patch areas, and geographical distance between patches. To assess the influence of high‐level taxa approaches on spider assemblage patterns, analyses were carried out individually for family, genera and species levels. Additionally, Mantel tests were carried out in underlying similarity matrices between each taxon. Significant differences in spider abundances among forest habitats were found. Pinus plantations showed the highest abundance of spiders and Eucalyptus plantations showed the lowest abundance. Spider abundance was significantly influenced by patch ages, geographical distance and vegetation cover. Expected numbers of families, genera and species did not vary among forest habitats. Spider composition of two Eucalyptus patches differed from the other forest patches, probably due to their low vegetation cover and isolation. Genera composition was the best correlate of species composition, showing that a higher‐level surrogate can be an alternative to the species approach. The understorey spider diversity in this managed area could be maintained when suitable habitat structures are provided, thus ensuring the connectivity between different habitat types. Further studies should focus on individual species responses to the conversion of native forest to monocultures.     

Inbreeding depression in Vriesea gigantea,a perennial bromeliad from southern Brazil

Inbreeding depression is a reduction of fitness in the progeny of closely related individuals and its effects are assigned to selfing or biparental inbreeding. Vriesea gigantea is a self‐compatible bromeliad species distributed in the Brazilian Atlantic rainforest and habitat destruction and fragmentation and collection have decreased the natural populations. We aim to describe the occurrence of inbreeding depression (δ) in three natural populations of V. gigantea and to correlate this phenomenon with previous studies of fertility, genetic diversity, population genetic structure, gene flow, mating system and seed dispersal in this species. Fifty‐four adult plants were sampled and 108 flowers were used for pollination treatments (selfing, outcrossing and control). For adult plants, we analysed plant and inflorescence height, flower numbers and seed set. In the progenies, evaluated parameters included seed germination and seedling survival rate. The results indicated low to moderate levels of inbreeding depression in V. gigantea (δ = 0.02 to 0.39), in agreement with molecular data from a previous study. Vriesea gigantea populations tolerate some degree of inbreeding, which is consistent with previous results on fertility, mating system, genetic diversity and gene flow. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169 , 312–319.     

Morphological abnormalities in elasmobranchs

A total of 10 abnormal free‐swimming (i.e. post‐birth) elasmobranchs are reported from The (Persian–Arabian) Gulf, encompassing five species and including deformed heads, snouts, caudal fins and claspers. The complete absence of pelvic fins in a milk shark Rhizoprionodon acutus may be the first record in any elasmobranch. Possible causes, including the extreme environmental conditions and the high level of anthropogenic pollution particular to The Gulf, are briefly discussed.     

Priority areas for the conservation of subtropical indigenous forest in southern Africa: a case study from KwaZulu-Natal

Southern Africa's subtropical forest biome, though small and highly fragmented, supports much of the region's biodiversity. With limited resources available for conservation and the exploitative use of forest escalating, identifying a network of priority forest reserves is important. We examine the distribution of forest birds, butterflies and mammals in KwaZulu-Natal, South Africa. Using an iterative algorithm we explore the efficiency of existing protected areas, species richness and rarity hotspots, prime forest sites (selected by forest area) and complementary networks as alternative approaches to priority reserve selection, as well as the potential use of indicator taxa. Existing protected areas represent 98% of species but are relatively inefficient in terms of area. Alternative selection criteria represent a high proportion of species (86–92%) and provide efficient bases for developing fully representative reserve networks. All species are represented within a network of 22 complementary quarter degree cells. This network includes several larger forests and existing protected areas and is recommended for priority conservation. Complementary networks identified separately for birds, butterflies and mammals overlap little, but each represents a high proportion of the remaining taxa, supporting their potential as representative 'indicator' taxa. The evolutionary history of the three main forest types in KwaZulu-Natal explains observed spatial patterns of alternative reserve networks. Priority areas are concentrated in scarp and coastal forest belts, regions of comparatively recent evolutionary activity with high species richness. Afromontane forest is older and less diverse, but its inclusion in any reserve network is necessary for the full representation of forest diversity.     

Nurse rocks influence forest expansion over native grassland in southern Brazil

Questions: Do small rocky outcrops favor forest plant colonization and establishment in grasslands? If so, what are the potential mechanisms involved in this process? Location: Araucaria forest and Campos grassland mosaic in southern Brazilian highlands (29°29′S, 50°12′W). Methods: We collected data on the density of forest woody species in plots located on rocky outcrops and in open fields subject to different management regimes. We evaluated the influence of outcrops on the density of forest plants ≤60‐cm tall, and the effects of other environmental variables and of site on plant density; we also used information on diaspore traits of the species to discuss the way in which plants disperse to the outcrops. Results: Rocky outcrops harbored a significantly higher density of forest plants than open fields, irrespective of site effect, and rock height was the best predictor for plant density on outcrops. Diaspores of all recorded species possess characteristics associated with dispersal by birds or mammals or by both. Conclusions: Small rocky outcrops markedly influence forest expansion by acting as perches for vertebrate dispersers and as nurse objects and safe sites for plants. Forest expansion starting in small outcrops possibly occurs as follows: perching of dispersers and increase of seed rain on rocks, promotion of better conditions of establishment for forest plants by nurse rocks, protection of plants sensitive to grazing and fire, and nucleation of forest vegetation.     

Tolerance and resilience of forest species to frost in restoration planting in southern Brazil

Listing potential species for restoring areas has become a complex task considering the lack of information regarding the silvicultural behavior of native trees after planting and their responses to environmental conditions. Frost is an important meteorological phenomenon that regulates the distribution of plant species, especially in subtropical regions. Thus, we evaluated the effect of frost and the resilience potential of native forest species in restoration planting of a riparian forest in southern Brazil. The experimental design used was randomized blocks in a 6 × 2 factorial scheme (6 species and 2 containers). During the winter in 2014 (270 days after planting), the damage from the impact of frost was assessed through a rating scale ranging from 0 (100% of the leaf area and damaged stem) to 10 (no visual damage). In addition, to assess species resilience, the height and stem diameter were measured, prior to the winter of 2014 and at 270 and 360 days. Eugenia involucrata and Schinus terebinthifolius were considered frost tolerant species. Parapiptadenia rigida was classified as moderately frost tolerant, while Casearia sylvestris, Cupania vernalis, and Inga vera were very sensitive to frost. Casearia sylvestris, E. involucrata, P. rigida, and S. terebinthifolius showed potential for recommencement of growth. On the other hand, C. vernalis and I. vera were considered too sensitive to frost, with high mortality rates and/or no resilience potential.     

On cloacal gestation in angel sharks from southern Brazil

The anatomy of the reproductive organs of the gravid female angel sharks Squatina Guggenheim and S. occulta was studied in specimens obtained by bottom trawling off southern Brazil from 1980 to 1992. Gestation of the species is lecithotrophic, lasts 11 months and is synchronized at the population level. The ovulation and onset of gestation occur in summer (January–February) and parturition takes place in spring (November-December). The gestation of Squatina has two phases: uterine gestation during the first 4 months and cloacal gestation during the last 6 months. The transition between these phases occurs in the 5th month (May). During uterine gestation the uteri are turgid, distended longitudinally and transversally, and constricted at both ends. Embryos develop within the closed uteri. During cloacal gestation the dome-shaped uteri are contracted longitudinally and are constricted near the nidamental gland. At the posterior end, they are distended transversally to form a wide opening into the cloaca. The cloaca is distended longitudinally and transversally. The embryos complete their development within the single, heart-shaped, uterine-cloacal chamber, that is open to the exterior through the cloacal Vent.     

Cytogenetic studies in six species of Scinax (Anura,Hylidae) clade Scinax ruber from northern and northeastern Brazil

Scinax species are still underrepresented in cytogenetic studies, mainly with respect to populations from northeastern and northern Brazil. In this study, we provide new chromosomal information on Scinax boesemani, S. camposseabrai, S. garbei, S. pachycrus, S. trilineatus and S. x-signatus, all belonging to clade S. ruber. They were collected at two locations in the Caatinga biome (northeastern Brazil) and at one in the Amazon (northern Brazil) biomes. Chromosomes were analyzed by conventional staining, C-banding, Ag-NOR staining, and fluorochrome staining. All species shared a modal diploid value of 2n = 24 and fundamental arm number (FN) of 48. Moreover, both chromosomal size and morphology were similar to other species in this Scinaxclade. C-banding revealed centromeric heterochromatin in all species, along with terminal species-specific C-bands in some species. Active nucleolar organizer regions (Ag-NORs) were identified at 11q in most species, except for S. boesemani and S. garbei (Ag-NORs at interstitial region of 8q). Differing from most anurans, GC-rich regions were not restricted to NORs, but also coincident with some centromeric and terminal C-bands. These data contribute to the cytotaxonomy of Scinax by providing chromosomal markers and demonstrating the occurrence of microstructural rearrangements and inversions on chromosomal evolution of Scinax.     

Morphological abnormalities in the cladoceran Ilyocryptus spinifer (Apipucos Reservoir, Pernambuco State, Brazil).

In a sample taken from Apipucos Reservoir (Recife, PE, Brazil) for taxonomic study, a high percentage (40%) was found of cladoceran Ilyocryptus spinifer individuals with morphological abnormalities on their postabdomen. There was not a fixed pattern of the malformations, which varied in gravity, and could affect the postanal spines or terminal claws. The postabdominal abnormalities are described and compared to the ones described in the literature. The hypothesis of the morphological abnormalities being induced by an occasional environmental toxicant is discussed.     

Dung beetle communities as biological indicators of riparian forest widths in southern Brazil

Riparian forests provide important habitat for many wildlife species and are sensitive to landscape change. Among terrestrial invertebrates, dung beetles have been used to investigate the effects of environmental disturbances on forest structure and diversity. Since many studies demonstrated a negative response of dung beetle communities to increasing forest fragmentation, and that most dung beetle species had a more pronounced occurrence during warmest seasons, three hypotheses were tested: (1) Scarabaeinae richness, abundance, diversity and evenness are lower in thinner riparian zone widths than in wider widths during the warmest seasons; (2) Scarabaeinae richness and abundance are positively influenced by leaf litter coverage and height and canopy cover; and (3) Scarabaeinae composition varies with the reduction in riparian vegetation and among annual seasons. We selected four fragments with different riparian zone widths in three secondary streams in southern Brazil. In each fragment, four sampling periods were carried out seasonally between spring 2010 and winter 2011. We collected dung beetles using pitfall traps with two types of bait. We collected 1289 specimens distributed among 29 species. In spring and summer, dung beetle richness was higher in fragments with the widest riparian zone than in those with a thinner riparian zone, and it did not vary between fragments in fall and winter seasons. Dung beetle abundance did not differ among fragments with different riparian zone widths, but it was higher in spring and summer than fall and winter. Richness and abundance were positively influenced by leaf litter. While dung beetle diversity was higher in fragments with wider riparian zone widths than in those with thinner widths, the evenness was similar among fragments. Dung beetle composition differed between the fragments with the widest and thinnest riparian zones, and it also varied among the seasons. Our results suggest that decreased riparian zones affect negatively to dung beetle community structure in southern Brazil. Fragments with thinner riparian zones had lower beetle richness in warmest seasons and an altered community composition. In this sense, the dung beetles are potentially good indicators of riparian forest fragmentation since some species were indicators of a particular riparian zone width. From a conservation perspective, our results demonstrate that the new Brazilian Forest Code will greatly jeopardize not only the terrestrial and aquatic biodiversity of these ecosystems, but also countless other ecological functions.