Habitat heterogeneity and use of physical acoustic space in anuran communities in southeastern Brazil.

We intended to verify if structural and physiognomical characteristics of water bodies influence on the degree of overlap among calling sites of 23 anurans species, if anuran species use different calling sites in different water bodies, and if there is some relationship between the degree of advertisement call (based on seven call features) and calling site differentiation. Then, we determined calling sites (based in four variables) and recorded the advertisement call for anuran species that occurred in 10 water bodies of northwestern São Paulo State. We also determined the environmental heterogeneity (based in four environmental descriptors) for each water body. Males of most species used similar calling sites in each water body, probably because of the high uniformity of the environment, as a consequence of agricultural impacts on edge vegetation of the studied ponds. Most species (18 out of 19 species) called from different sites in the ponds where they occurred, which can be associated with differences in horizontal and vertical distribution of vegetation in the studied ponds. From the 19 species analyzed, only males of Pseudopaludicola aff. saltica called in sites with the same characteristics in different ponds. Advertisement call of Hylidae species was more similar to each other than were Leiuperidae and Leptodactylidae among themselves. The aquatic/terrestrial anurans (Bufonidae, Leiuperidae, Leptodactylidae and Microhylidae) occupied similar calling sites but presented quite distinct advertisement calls, while Hylidae species presented an inverse pattern: a high similarity on advertisement call features but used different calling sites, which indicates a niche complementarity between physical (calling site use) and acoustic (advertisement call) space use.

Ticks (Acari: Ixodidae) on Wild Marsh-Deer (Blastocerus dichotomus) from Southeast Brazil: Infestations before and after Habitat Loss

The lake from Porto-Primavera hydroelectric power station inundated an area of 2,200 km2 at the border of São Paulo and Mato-Grosso do Sul States, Brazil. Infestations by ticks were evaluated on 135 marsh deer, Blastocerus dichotomus (Illiger), captured before and after inundation. Ticks were collected for identification, and infestation level of animals was assessed by scoring. Deer were divided into four groups according to capture location and temporal relation to the inundation. Groups 1, 2, and 3 were captured before inundation. Group 4 was captured after inundation. Four tick species were found: Amblyomma cajennense (F.), Amblyomma triste Koch, Anocentor nitens (Neumann), and Boophilus microplus (Canestrini). Groups 1, 2, 3, and 4 had 30, 45, 100, and 96%, respectively, of animals carrying B. microplus ticks. A. triste was observed on 16, 22, 22, and 88% of animals from groups 1,2,3, and 4, respectively. A. nitens and A. cajennense were observed only on group 4, on 32 and 16% of the animals, respectively. Groups 1 and 2 had only 4.8 and 6.1% of animals with high infestation levels, respectively, and no ticks on 46.8% and 45.5% of the animals, respectively. Conversely, groups 3 and 4 lacked noninfested animals and had high infestation levels on 77.8 and 50% of deer, respectively. Marsh area shrinkage was blamed for higher infestation levels on deer from groups 3 and 4. The widespread presence of A. triste on marsh deer, a Neotropical tick species, raises the possibility of a natural host-parasite relationship.

Habitat, distribuição e aspectos adaptativos de peixes da microbacia do ribeirão Grande, Estado de São Paulo, Brasil

The ichthyofauna of ribeirão Grande microbasin that runs through one of the few remaining fragments of Atlantic Forest (in Mantiqueira mountain range, Valley of Paraíba) was studied. Fish samples were obtained with an electric fishing powered by a maximum capacity generator of 155 V and 60-Hz alterning current, gill-nets and traps. In three collecting days, during July/2001, October/2001, January/2002 and April/2002, 2865 fishes were sampled. These fishes belonged to 12 families, 23 genera and 37 species. The species were more abundant between the piedmont and the plain of the Valley of Paraíba. The Characidium, Trichomycterus genera and the Imparfinis minutus species presented only one ovary or testis and no swim bladder. The ecological significance of morphological features in stream mountain fishes was used to predict the niche adaptation for those conditions, towards K-strategy.

Photosynthetic responses to temperature in tropical lotic macroalgae

A comparative analysis of the photosynthetic responses to temperature (10-30°C) was carried out under short-term laboratory conditions by chlorophyll fluorescence and oxygen (O2) evolution. Ten lotic macroalgal species from southeastern Brazil (20°11-20°48′S, 49°18-49°41′W) were tested, including Bacillariophyta, Chlorophyta, Cyanophyta, Rhodophyta and Xanthophyta. Temperature had significant effects on electron transport rate (ETR) only for three species (Terpsinoe musica, Bacillariophyta; Cladophora glomerata, Chlorophyta; and C. coeruleus, Rhodophyta), with highest values at 25-30°C, whereas the remaining species had no significant responses. It also had similar effects on non-photochemical quenching and ETR. Differences in net photosynthesis/dark respiration ratios at distinct temperatures were found, with an increasing trend of respiration with higher temperatures. This implies in a decreasing balance between net primary production and temperature, representing more critical conditions toward higher temperatures for most species. In contrast, high net photosynthesis and photosynthesis/dark respiration ratios at high and wide ranges of temperature were found in three species of green algae, suggesting that these algae can be important primary producers in lotic ecosystems, particularly in tropical regions. Optimal photosynthetic rates were observed under similar environmental temperatures for five species (two rhodophytes, two chlorophytes and one diatom) considering both techniques, suggesting acclimation to their respective ambient temperatures. C. coeruleus was the only species with peaks of ETR and O 2 evolution under similar field-measured temperatures. All species kept values of ETR and net photosynthesis close to the optimum under a broad range of temperatures. Increased non-photochemical quenching, as a measure of thermal dissipation of excess energy, toward higher temperatures was observed in some species, as well as positive correlation of non-photochemical quenching with ETR, and were interpreted as two mechanisms of adaptation of the photosynthetic apparatus to temperature changes. Different optimal temperatures were found for individual species by each technique, generally under lower temperatures by O2 evolution, indicating dependence on distinct factors: increases in temperature generally induced higher ETR due to increased enzymatic activity, whereas increments of enzymatic activity were compensated by increased respiration and photorespiration leading to decreases in net photosynthesis.

The influence of fruit morphology and habitat structure on ant-seed interactions: A study with artificial fruits

Artificial fruits designed to simulate lipid-rich non-myrecochorous diaspores were used to test for the effect of fruit morphology and habitat structure on ant-seed interactions in an Atlantic Forest site in SE Brazil. The outcome of the interaction (i.e., if the fruit was removed, cleaned by ants on the spot or had no interaction with ants) and the time of ant response were the investigated variables. Models simulating drupes and arilate diaspores were used to test for morphological effects and four habitat attributes (litter depth, number of logs, number of trees, and percentage of bromeliad coverage on the forest floor), likely to be correlated with the ant diversity and abundance in the study site, were measured to test for the effect of habitat structure. The proportion of fruits removed or cleaned did not differ between the two morphological models. Sites in which fruits were cleaned had more trees than those in which no interaction occurred. This may be a result of the foraging behavior of arboreal ants that frequently descend to the forest floor to exploit fleshy diaspores. Sites in which model removal occurred had lower litter depth than both those in which models were cleaned and those in which no interaction occurred. A negative correlation was observed between litter depth and ant response time. Accumulation of leaf litter at a given point may have constrained the movements of large ants in general, and ponerine ants (that are important seed removers) in particular. We conclude that that local pattern in litter depth and tree density influence the frequency and outcome of interactions between ants and non-myrmecochorous, fleshy diaspores.

Feeding habits and habitat use in Bothrops pubescens (Viperidae, Crotalinae) from southern Brazil

Bothrops pubescens is a member of the neuwiedi complex that occurs in southern Brazil and Uruguay. We studied the ecology of B. pubescens from a field site (at Santa Maria, Rio Grande do Sul, Brasil) and based on preserved specimens from the state of Rio Grande do Sul, Brasil. In Santa Maria, individuals were collected during visual encounter surveys (VES), in pitfall traps with drift fences and during incidental encounters. Most snakes found in the field were on the ground, mainly on leaf litter, in mosaics of light and shadow or in completely shaded areas. In disturbed areas, snakes were usually associated with country houses and agricultural fields. Snakes were found much more frequently in forests and forest edges than in open habitats. The diet of B. pubescens comprised small mammals (56.2% of individual prey found), anurans (21.2%), lizards (7.5%), snakes (7.5%), birds (5.0%), and centipedes (2.5%). Prey predator mass ratios ranged from 0.002-0.627, and larger snakes tended to consume larger prey. Bothrops pubescens seems to be able to survive in disturbed areas, mainly those close to forests, and this ability may be facilitated by its generalized feeding habits. Copyright 2005 Society for the Study of Amphibians and Reptiles.

Distribution and habitat use of Sordellina punctata (Serpentes, Colubridae), with a new record from State of São Paulo, Brazil

Sordellina punctata occurs throughout south and southeastern Brazil in the Atlantic Forest domain (states of São Paulo, Paraná and Santa Catarina). Records from the states of Rio de Janeiro and Mato Grosso do Sul are questionable. A new record from southwestern São Paulo extends its distribution west and northward, probably indicating a wider range in the past. Habitat use in S. punctata implies that it may be more associated with wetlands and other saturated areas than truly aquatics ones.

Functional feeding habits of Chironomidae larvae (Insecta, Diptera) in a lotic system from Midwestern region of São Paulo State, Brazil

Functional feeding habits of Chironomidae larvae (Insecta, Diptera) in a lotic system from Mid-western region of São Paulo State, Brazil were analyzed. Collectors were the dominant organisms, repre-sented by genera Chironomus, Fissimentum and Cryptochironomus, following by shredders and predators.

Habitat heterogeneity and use of physical and acoustic space in anuran communities in Southeastern Brazil

Habitat heterogeneity and use of physical and acoustic space in anuran communities in Southeastern Brazil. We intended to verify if structural and physiognomical characteristics of water bodies influence on the degree of overlap among calling sites of 23 anurans species, if anuran species use different calling sites in different water bodies, and if there is some relationship between the degree of advertisement call (based on seven call features) and calling site differentiation. Then, we determined calling sites (based in four variables) and recorded the advertisement call for anuran species that occurred in 10 water bodies of northwestern São Paulo State. We also determined the environmental heterogeneity (based in four environmental descriptors) for each water body. Males of most species used similar calling sites in each water body, probably because of the high uniformity of the environment, as a consequence of agricultural impacts on edge vegetation of the studied ponds. Most species (18 out of 19 species) called from different sites in the ponds where they occurred, which can be associated with differences in horizontal and vertical distribution of vegetation in the studied ponds. From the 19 species analyzed, only males of Pseudopaludicola aff. saltica called in sites with the same characteristics in different ponds. Advertisement call of Hylidae species was more similar to each other than were Leiuperidae and Leptodactylidae among themselves. The aquatic/terrestrial anurans (Bufonidae, Leiuperidae, Leptodactylidae and Microhylidae) occupied similar calling sites but presented quite distinct advertisement calls, while Hylidae species presented an inverse pattern: a high similarity on advertisement call features but used different calling sites, which indicates a niche complementarity between physical (calling site use) and acoustic (advertisement call) space use. © 2008 Departamento de Ciências Biológicas.

Urban poverty and habitat precariousness in the Caribbean

Includes bibliography

Bait and habitat preferences, and temporal variability of social wasps (Hymenoptera: Vespidae) attracted to vertebrate carrion

In addition to feeding on carrion tissues and fluids, social wasps can also prey on immature and adult carrion flies, thereby reducing their populations and retarding the decomposition process of carcasses. In this study, we report on the occurrence and behavior of social wasps attracted to vertebrate carrion. The collections were made monthly from September 2006 to October 2007 in three environments (rural, urban, and forest) in six municipalities of southeast Brazil, using baited bottle traps. We collected Agelaia pallipes (Olivier, 1791) (n = 143), Agelaia vicina (Saussure, 1854) (n = 106), Agelaia multipicta (Haliday, 1836) (n = 18), and Polybia paulista Ihering, 1896 (n = 3). The wasps were observed feeding directly on the baits and preying on adult insects collected in the traps. Bait and habitat associations, temporal variability of social wasps, and possible forensic implications of their actions are discussed. © 2011 Entomological Society of America.

First telemetry study of bush dogs: Home range, activity and habitat selection

Context The bush dog (Speothos venaticus) is difficult to observe, capture, and study. To date, indirect evidence and opportunistic field observations have been the primary sources of information about the species' ecology. Field data are urgently needed to clarify the species' ecological requirements, behaviour and movement patterns. Aims The present study uses 13 months of telemetry data from a group of bush dogs to begin to address questions about area requirements, habitat preferences and movement patterns of this difficult-to-study species. Methods We tracked a group of bush dogs (two adults, one juvenile, four young) in an area of intact and altered Cerrado (woodlandsavanna biome) in eastern Mato Grosso, Brazil (Nova Xavantina District). Key results The group had a total home range of 140km2 (fixed kernel 95%), with smaller seasonal 'subareas' (areas used for 12 months before moving to another area, with repetition of some areas over time) and demonstrated a preference for native habitats. Conclusions The bush dog's home range is greater than that of other canids of the same size, even correcting for group size. Patterns of seasonal movement are also different from what has been observed in other South American canids. Implications From our observations in the Brazilian savanna, bush dogs need large tracks of native habitat for their long-term persistence. Although the present study is based on a single pack, it is highly relevant for bush dog conservation because it provides novel information on the species' spatial requirements and habitat preferences. © 2012 CSIRO.

Mangrove habitat partitioning by Ucides cordatus (Ucididae): Effects of the degree of tidal flooding and tree-species composition during its life cycle

Environmental factors strongly affect mangrove crabs, and some factors modulate population structure and habitat partitioning during the crabs' life cycle. However, the effect of these environmental factors on habitat selection by mangrove crabs is still unknown. We evaluated habitat selection by the mangrove crab Ucides cordatus in mangrove forests with different degrees of predominance of Rhizophora mangle, Laguncularia racemosa or Avicennia schaueriana, two tidal flooding levels (less- and more-flooded), and two biological periods (breeding and non-breeding seasons). Sampling was conducted in four mangrove forests with different influences of these biotic and abiotic parameters. We used the data for sex ratio to explain environmental partitioning by this species. Females predominated in R. mangle mangroves, independently of the biological period (breeding or non-breeding seasons), and males predominated only in the less-flooded L. racemosa mangroves. The flooding level affected the sex ratio of U. cordatus, with a predominance of males in less-flooded mangroves, independently of the biological period; and a gender balance in the more-flooded mangroves only during the breeding season. Outside the breeding season, the largest specimens were recorded in the R. mangle mangroves, but in the breeding season, the largest crabs were recorded in the L. racemosa mangroves with a higher level of flooding. These results suggest that tree-species composition and tidal flooding level can have a significant effect on the habitat partitioning of sexes and sizes of the mangrove crab U. cordatus both during and outside the breeding season. © 2012 Springer-Verlag and AWI.

How individual movement response to habitat edges affects population persistence and spatial spread

How individual-level movement decisions in response to habitat edges influence population-level patterns of persistence and spread of a species is a major challenge in spatial ecology and conservation biology. Here, we integrate novel insights into edge behavior, based on habitat preference and movement rates, into spatially explicit growth-dispersal models. We demonstrate how crucial ecological quantities (e.g., minimal patch size, spread rate) depend critically on these individual-level decisions. In particular, we find that including edge behavior properly in these models gives qualitatively different and intuitively more reasonable results than those of some previous studies that did not consider this level of detail. Our results highlight the importance of new empirical work on individual movement response to habitat edges. © 2013 by The University of Chicago.

Modeling Habitat Split: Landscape and Life History Traits Determine Amphibian Extinction Thresholds

Habitat split is a major force behind the worldwide decline of amphibian populations, causing community change in richness and species composition. In fragmented landscapes, natural remnants, the terrestrial habitat of the adults, are frequently separated from streams, the aquatic habitat of the larvae. An important question is how this landscape configuration affects population levels and if it can drive species to extinction locally. Here, we put forward the first theoretical model on habitat split which is particularly concerned on how split distance - the distance between the two required habitats - affects population size and persistence in isolated fragments. Our diffusive model shows that habitat split alone is able to generate extinction thresholds. Fragments occurring between the aquatic habitat and a given critical split distance are expected to hold viable populations, while fragments located farther away are expected to be unoccupied. Species with higher reproductive success and higher diffusion rate of post-metamorphic youngs are expected to have farther critical split distances. Furthermore, the model indicates that negative effects of habitat split are poorly compensated by positive effects of fragment size. The habitat split model improves our understanding about spatially structured populations and has relevant implications for landscape design for conservation. It puts on a firm theoretical basis the relation between habitat split and the decline of amphibian populations. © 2013 Fonseca et al.