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1. Spatial and temporal variation in networks has been reported in different studies. However, the many effects of habitat structure and food resource availability variation on network structures have remained poorly investigated, especially in individual‐ based networks. This approach can shed light on individual specialization of resource use and how habitat variations shape trophic interactions. 2. To test hypotheses related to habitat variability on trophic interactions, we investigated seasonal and spatial variation in network structure of four populations of the marsupial Gracilinanus agilis in the highly seasonal tropical savannas of the Brazilian Cerrado. 3. We evaluated such variation with network nestedness and modularity considering both cool‐dry and warm‐wet seasons, and related such variations with food resource availability and habitat structure (considered in the present study as environmental variation) in four sites of savanna woodland forest. 4. Network analyses showed that modularity (but not nestedness) was consistently lower during the cool‐dry season in all G. agilis populations. Our results indicated that nestedness is related to habitat structure, showing that this metric increases in sites with thick and spaced trees. On the other hand, modularity was positively related to diversity of arthropods and abundance of fruits. 5. We propose that the relationship between nestedness and habitat structure is an outcome of individual variation in the vertical space and food resource use by G. agilis in sites with thick and spaced trees. Moreover, individual specialization in resource‐rich and population‐dense periods possibly increased the network modularity of G. agilis. Therefore, our study reveals that environment variability considering spatial and temporal components is important for shaping network structure of populations.

Food availability is considered to be a primary factor affecting animal populations, yet few experimental tests have been performed to evaluate its actual importance in species-rich ecosystems such as rainforests. It has been suggested that in such systems certain plant species may act as “keystone” resources for animals, but the importance of presumed keystone resources for populations has not been quantified experimentally. Using complementary seed removal and seed-addition experiments, we determined how the supply of a presumed keystone resource, seeds of Araucaria angustifolia, affects short-term demography of their main consumer group (small rodents) in a biodiversity hotspot, the Brazilian Atlantic Forest. We hypothesized that (i) the harvest of A. angustifolia seeds by human populations has negative impacts on rodents, and (ii) these seeds are a limiting resource for rodent populations. To test these hypotheses, we monitored populations of two species of numerically dominant rodents (Delomys dorsalis and Akodon montensis) within replicated control-experimental plots. Manipulations of seed supply over 2 years had little effect on population size, body condition, survival, or reproduction of the two rodents, suggesting that, in the short-term (within one generation), their populations are not food limited in Araucaria forests. Despite apparently having all the characteristics of a keystone resource, as currently defined in the literature, the seeds of A. angustifolia had limited influence on the short-term demography of their main consumer group. In situations where purported keystone resources are seasonally abundant, their actual importance may be lower than generally assumed, and these resources then may have only localized and temporary effects on consumer populations.

Scatter-hoarding rodents may interact with the structural characteristics of their environment in several ways: by seeking dense areas inside the forest for protection during seed handling, by caching seeds close to objects that might be used as visual cues for seed recovery or by hiding themselves inside refuges such as burrows. We investigated the use of structural characteristics of the forest by a scatter-hoarder rodent (the Azara's agouti, Dasyprocta azarae) in the Brazilian Araucaria Forest. We evaluated the selection of microhabitat characteristics for feeding or caching seeds, and the selection of potential landmarks for increasing seed recovery rates. For that, we followed threaded seeds of Araucaria angustifolia (Araucariaceae) and also placed artificial caches in the forest. We predicted that agoutis (1) select feeding and caching sites whose microhabitat characteristics potentially enhance protection against predators, (2) hoard seeds preferentially near potential landmarks and (3) find artificial caches placed near potential landmarks more frequently than caches placed away (

We studied the seed predation and scatter-hoarding behaviour of Azara's agoutis Dasyprocta azarae (Rodentia: Dasyproctidae) in relation to the seeds of the Brazilian ‘pine’, Araucaria angustifolia (Araucariaceae), the rodent's main winter food source. We compared seed-removal rates, seed-caching rates, cache distances and recovery rates between a summer period of food abundance (with a low demand for A. angustifolia seeds and no such seeds naturally available) and a winter period of food scarcity (with a high demand for A. angustifolia seeds). We investigated whether the relative seed value affected the rodent's seed-handling behaviour. We predicted that during the high seed-demand period (winter): (1) cache distances would be greater; (2) fewer seeds would be stored; (3) more seeds would be recovered and the seed-recovery time would be lower. In support of our first two predictions, the caching distances were greater in winter (mean ± SE = 15.67 ± 5.11 m) than in summer (9.40 ± 1.59 m), and agoutis hoarded >9 times more seeds in summer (55) than in winter (6). Our third prediction was not supported, and the proportion of unrecovered caches and buried seed recovery times did not differ between winter (mean ± SE = 3.00 ± 0.00 days, n = 5 seeds) and summer (11.05 ± 3.68 days, n = 20 seeds). The high resource density (during summer) rather than the density of A. angustifolia seeds likely influenced seed fate. Agoutis acted mainly as predators, leaving few intact seeds, caching a low proportion of handled seeds (≅ 8%) and rapidly consuming the caches. Agoutis may cache seeds to keep them safe from competitors on a short-term basis rather than maintaining medium- or long-term reserves for use during food-scarcity periods.

Patterns in distribution and local abundance of species within a biome are central concerns in ecology and allow the understanding of the effects of habitat loss on rates of species extinction; provide support for the creation and management of reserves; and contribute to the identification and quantification of the processes that allow niche partitioning by species. However, despite the importance in the conservation and management of the ecosystems, most systematized information on the abundance and distribution of small mammals is restricted to the northern hemisphere or forest ecosystems. For tropical biomes, an important part of this information remains dispersed and difficult to access in the form of theses, technical reports, or unpublished data sets. Here we present a comprehensive data set of abundance and richness of small mammals in the Cerrado, the largest Neotropical savanna. This data set includes 2,599 records of 446 sites from 96 studies. More than 50% of references in this data set are peer-reviewed journal articles, but 45.78% of communities were compiled from theses. The data set comprises 24,283 individuals of 55 genera and at least 118 species of small mammals including 29 marsupials, two lagomorphs (one exotic), and 87 rodents (three exotic). Local species richness ranged from 1 to 26 species (5.82 ± 3.55, average species richness ± SD). We observed hyperdominance of a few species; the 10 most abundant species in this data set represented 60.19% of all recorded individuals. The hairy-tailed bolo mouse (Necromys lasiurus) represented over than 20% of all individuals and occurred at more than 50% of sites. Furthermore, we identified 18 environments, 16 native vegetation types, and 2 anthropic environments. Typical savanna and gallery forest were the most frequently sampled vegetation types (comprising 46.94% of all sampled sites) and the most speciose ones (57 species for typical savanna and 53 species for gallery forest). The information contained in this data set can be used to analyze ecological questions such as the relationship between local abundance and regional distribution, the relevance of local and regional factors to community structuring, and the role of phylogenetic mechanisms in community assemblage. It can also be useful in conservation efforts in this biodiversity hotspot. No copyright, proprietary, or cost restrictions apply. Please cite this paper when the data are used in publications. We also request that researchers and teachers inform us of how they are using the data.

Mechanisms that favour the co-occurrence of morphologically and ecologically similar species in South America are potentially relevant, because two or more species often occur in sympatry. In the present study, we investigated possible mechanisms of resource partitioning between two sympatric species of foxes, the crab-eating fox Cerdocyon thous and the pampas fox Pseudalopex gymnocercus, in the National Park of Aparados da Serra in southern Brazil (29°10′S, 50°05′W). We considered three main niche dimensions – habitat, diet and time – and evaluated the overlap between the two species in these dimensions. We conducted the study from June 2000 to October 2001 in an area composed of open grasslands and Araucaria forests. We studied the foxes by using a combination of scat analysis and direct observation. A comparison of their diet indicated that it was very similar for both species in all seasons (Pianka's indexes ranging from 0.920 to 0.957). The most common food item for both species of foxes was rodents, followed by coleopterans, birds and plant remains (seeds and fruits). As expected by the niche-complementarity hypothesis, we detected differences along other niche axes. Pseudalopex gymnocercus seemed to occur only in open areas, including grasslands and dirt roads, whereas C. thous was more generalist in habitat use, occurring both inside and at the edge of forests. However, both fox species were common in grassland habitats, where they might compete for resources. The differences were more marked for activity time, with the crab-eating fox being significantly more nocturnal (circular mean of time of sighting=23:39 h, se=56 min) than the pampas fox (circular mean=19:56 h, se=64 min; Watson's F=6.06, P=0.02). We suggest that the larger C. thous could be limiting the activity of P. gymnocercus by interference competition.

Land flatworms (Platyhelminthes: Terricola) are sensitive to environmental changes and might be used as biological indicators of the degree of disturbance of their habitats. Nevertheless, studies on the structure of land flatworm communities are rare. In the present study, we investigated the terrestrial flatworm communities in two types of ombrophilous forest, Atlantic forest and Araucaria forest, aiming to answer the following questions: (1) Is the community structure of the two types of ombrophilous forest different? (2) Are there differences, regarding community structure, among distinct fragments of Araucaria forest? (3) Are there indicators of edge effects in these communities? The study site, the National Park of Aparados da Serra, is mainly covered, at high altitudes, by fragments of Araucaria forest immersed in a matrix of open areas (grasslands) and, in low altitudes, by a continuous Atlantic forest. We conducted monthly surveys in the two types of forest with three replications per forest type over a period of 2 years. Results indicated that: (1) community structure is clearly distinct between the two types of forest, as well as among fragments of the Araucaria forest; (2) there are no apparent edge effects; (3) the diversity indices of the two types of ombrophilous forest are not significantly different (Atlantic forest—H′=2.87, Araucaria forest—H′=2.55; p>0.05); and (4) there are significant differences in diversity indices between two fragments of Araucaria forest (H′=2.92 and 2.47; p

We investigated patterns of spatial distribution and microhabitat selection of rodents in a patch (26 ha) of mixed ombrophilous forest (or Araucaria forest), dominated by the Araucaria 'pine' Araucaria angustifolia, in the National Park of Aparados da Serra, RS, in southern Brazil. We conducted monthly trapping sessions lasting 6 days (from June 2000 to June 2001) using a square grid of 121 trap stations, separated by 15 m (2.25 ha). We measured 10 microhabitat variables that could influence species distribution. These variables were related to the occurrence of mammals by using canonical correspondence analysis (CCA) and stepwise multiple regression. The distribution patterns of the three most common rodents differed significantly (X 2 = 38.6; P < 0.002), with Delomys dorsalis being more clumped than the other two species. Both CCA and multiple regression analysis showed a significant effect of microhabitat variables on species occurrence. The multiple regression parameters for Oligoryzomys nigripes were R 2 = 0.142, P < 0.05, for Akodon montensis were R 2 = 0.222, P < 0.01, and for D. dorsalis R 2 = 0.323, P< 0.001. Variables that significantly influenced species distribution were vegetation density at 1 m height and length of fallen logs for O. nigripes, canopy cover for A. montensis, and vegetation density at 2 m height, quantity of leaves of Araucaria trees (negative relationship), tree density (except Araucaria trees), and number of potential shelters, for D: dorsalis. The results indicated that D. dorsalis is the most habitat specialist among the rodent species and that there are no apparent competitive interactions.

Measures of traits are the basis of functional biological diversity. Numerous works consider mean species-level measures of traits while ignoring individual variance within species. However, there is a large amount of variation within species and it is increasingly apparent that it is important to consider trait variation not only between species, but also within species. Mammals are an interesting group for investigating trait-based approaches because they play diverse and important ecological functions (e.g., pollination, seed dispersal, predation, grazing) that are correlated with functional traits. Here we compile a data set comprising morphological and life history information of 279 mammal species from 39,850 individuals of 388 populations ranging from −5.83 to −29.75 decimal degrees of latitude and −34.82 to −56.73 decimal degrees of longitude in the Atlantic forest of South America. We present trait information from 16,840 individuals of 181 species of non-volant mammals (Rodentia, Didelphimorphia, Carnivora, Primates, Cingulata, Artiodactyla, Pilosa, Lagomorpha, Perissodactyla) and from 23,010 individuals of 98 species of volant mammals (Chiroptera). The traits reported include body mass, age, sex, reproductive stage, as well as the geographic coordinates of sampling for all taxa. Moreover, we gathered information on forearm length for bats and body length and tail length for rodents and marsupials. No copyright restrictions are associated with the use of this data set. Please cite this data paper when the data are used in publications. We also request that researchers and teachers inform us of how they are using the data. Fil: Gonçalves, Fernando. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Bovendorp, Ricardo S.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Beca, Gabrielle. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Bello, Carolina. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Costa Pereira, Raul. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Muylaert, Renata L.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Rodarte, Raisa R.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Villar, Nacho. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Souza, Rafael. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Graipel, Maurício E.. Universidade Federal de Santa Catarina; Brasil Fil: Cherem, Jorge J.. Caipora Cooperativa, Florianopolis; Brasil Fil: Faria, Deborah. Universidade Estadual de Santa Cruz; Brasil Fil: Baumgarten, Julio. Universidade Estadual de Santa Cruz; Brasil Fil: Alvarez, Martín R.. Universidade Estadual de Santa Cruz; Brasil Fil: Vieira, Emerson M.. Universidade do Brasília; Brasil Fil: Cáceres, Nilton. Universidade Federal de Santa María. Santa María; Brasil Fil: Pardini, Renata. Universidade de Sao Paulo; Brasil Fil: Leite, Yuri L. R.. Universidade Federal do Espírito Santo; Brasil Fil: Costa, Leonora Pires. Universidade Federal do Espírito Santo; Brasil Fil: Mello, Marco Aurelio Ribeiro. Universidade Federal de Minas Gerais; Brasil Fil: Fischer, Erich. Universidade Federal do Mato Grosso do Sul; Brasil Fil: Passos, Fernando C.. Universidade Federal do Paraná; Brasil Fil: Varzinczak, Luiz H.. Universidade Federal do Paraná; Brasil Fil: Prevedello, Jayme A.. Universidade do Estado de Rio do Janeiro; Brasil Fil: Cruz-Neto, Ariovaldo P.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Carvalho, Fernando. Universidade do Extremo Sul Catarinense; Brasil Fil: Reis Percequillo, Alexandre. Universidade de Sao Paulo; Brasil Fil: Paviolo, Agustin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina Fil: Duarte, José M. B.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil. Fundación Oswaldo Cruz; Brasil Fil: Bernard, Enrico. Universidade Federal de Pernambuco; Brasil Fil: Agostini, Ilaria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina Fil: Lamattina, Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Ministerio de Salud de la Nación; Argentina Fil: Vanderhoeven, Ezequiel Andres. Ministerio de Salud de la Nación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina

The Cerrado biome is a complex of open forests, gallery forests and savanna vegetation that harbours about 60 species of small mammals. Despite the frequent occurrence of fire in this habitat, few studies have analysed its effects on the small mammal communities in the Cerrado. The purpose of this study was to compare small mammal communities of two Cerrado areas with different fire frequencies (2–3 years or more than 18 years since the last fire). Species diversity, species composition, and relative abundance of the most common species of these communities were analysed in both areas before and after fire. One trapping grid was established in each of the two areas. These areas were sampled monthly or bi-monthly during 1 year before and 1 year after prescribed fires. Both areas had communities with similar species composition, but the protected site had more species, before and after fire (seven and eight, respectively), than the frequently burned site (five and six species, respectively). Both sites showed significant post-fire changes for a short time period (3 months), but only the area that had been protected against fire for more time showed significant post-fire changes in relative abundance of the most common species (the murid rodents Bolomys lasiurus, Calomys callosus, C. tener, Oryzomys subflavus, and Thalpomys cerradensis) for the 1 year following fire. Overall diversity tended to be greater in the protected site both before and after fire. Species composition and diversity indices of the small mammal communities were relatively unaffected by the fires. Thalpomys cerradensis, however, appeared to use only areas that burn frequently and C. callosus showed an immediate post-fire increase in population size in both areas, contrasting with a simultaneous decrease in number of B. lasiurus.

Summary 1. The relationship between plant traits and the frequency of attack by a stem galling midge, Neolasioptera sp. (Diptera: Cecidomyiidae), on Eremanthus erythropappus (Asteraceae) was studied. The morphological changes of the host after a galler attack and the potential effects of these changes on attacks by the next generation of gallers were analysed. The study was conducted in the Serra do Japi, Sao Paulo, south-eastern Brazil. 2. Galled branches were significantly longer, thicker, and had more leaves than ungalled branches. Accordingly, gall establishment was higher in the longer and more foliose branches. Hence, it is suggested that ovipositing females are maximizing their performance by selecting larger branches. 3. Galled branches were larger than ungalled branches of the same age. Two hypotheses, not necessarily exclusive, can explain this pattern: (1) the plant vigour hypothesis that the females are choosing the more vigorous, fast-growing branches, which still remain more vigorous after galling; or (2) the resource regulation hypothesis that galling increases branch growth rates, thus increasing resource quality for forthcoming conspecifics. 4. Co-occurrence frequencies of current and past generation galls showed that the likelihood of a branch being galled increased when it, or the branch from which it stemmed, had been galled before. The data indicated that this preference was conditioned by the number of previous attacks. Heavier attack intensities, such as one gall in the same branch and another in the branch from which it stemmed, decreased the probability of further galling. 5. The suggested links between herbivore attack and plant traits indicate that studies on host selection by phytophagous insects must take into account that herbivory itself may change the plant traits that are postulated to be selected by the insects.