Biology subjects

Dalmolin, D. A.

Publications and source records attributed to Dalmolin, D. A..

8 recordsLinked to original sources

bioRxiv2021

Trait-environment relationship in tadpoles of the southern Atlantic Forest

O_LIEnvironmental predictors select individuals by their functional traits, shaping the anuran assembly patterns. Individuals respond to environmental filters that can be on a local or regional scale. C_LIO_LIIn this study, we investigated the association between local (water and microhabitat) and landscape variables and the morphological traits of tadpoles of ponds and streams. The study was conducted in the southern region of the Brazilian Atlantic Forest. We sampled 28 waterbodies and recorded 22 anurans species. We performed RLQ and fourth-corner analyses to determine the patterns of trait-environment relationships and determine which environmental and landscape variables influence the morphological characteristics of tadpoles from streams and ponds. C_LIO_LIWe found that the morphological traits of tadpoles are influenced mainly by physicochemical and microhabitat attributes, being distinct between ponds and streams. In ponds, water depth, pH, and the presence of vegetation influence the morphological traits of the tadpoles, while in the streams water pH, temperature, conductivity, total alkalinity, Alk HCO3, and microhabitat variables played a major role in defining the traits. C_LIO_LIOur results indicate that local components of habitat (water characteristics and microhabitat) influence functional traits of tadpoles in both ponds and streams, especially those supposedly related to locomotory, foraging and prey-detection abilities. C_LI

ecology↗

bioRxiv2021

Association between land use and composition of amphibian species in temperate Brazilian forest remnants

We evaluated the influence of landscape configuration on the diversity of anurans in Atlantic Forest remnants in southern Brazil. As natural habits provide better conditions for the survival of amphibians, we expected to find more diverse communities in areas with more forest cover. We sampled tadpoles in 28 breeding sites distributed in seven forest remnants. We recorded 22 anuran species and richness varied from 6 to 12 species between sites. Most of the recorded species were not forest specialists, except for Boana curupi and Crossodactylus schmidti. There was a significant overlap in the species composition between all remnants, and the Generalized Linear Mixed Model indicated that landscape use did not affect species richness. The PERMANOVA showed that forest and livestock farming explained the dissimilarity in the composition of the communities. One possible explanation for this is that the remnants are surrounded by a relatively well-preserved landscape, which offers favorable conditions for the maintenance of local populations and homogenizes species composition across the sampling sites. The lack of any strong association between tadpole species richness and land use suggests that anurans are primally affected by habitat characteristics that are detected only on a fine-scale analysis.

ecology↗

bioRxiv2020

Anuran assemblage changes along small-scale phytophysiognomies in natural Brazilian grasslands

We studied the species composition of frogs in two phytophysiognomies (grassland and forest) of a Ramsar site in southern Brazil. We aimed to assess the distribution of species on a small spatial scale and dissimilarities in community composition between grassland and forest habitats. The sampling of individuals was carried out through pitfall traps and active search in the areas around the traps. We evaluated the existence of these differences by using permutational multivariate analysis of variance and multivariate dispersion. We found 13 species belonging to six families. Leptodactylidae and Hylidae were the most representative families. The compositional dissimilarity was higher between the sampling sites from different phytophysiognomies than within the same phytophysiognomy, suggesting that forest and grassland drive anuran species composition differently. Also, the difference in anuran species composition between the sampling sites within the forest was considerably high. Based on our results, we could assume that the phytophysiognomies evaluated here offer quite different colonization opportunities for anurans, especially those related to microhabitat characteristics, such as microclimate variables.

ecology↗

bioRxiv2020

Living in a changing world: effects of roads and Pinus monocultures on an anuran metacommunity in southern Brazil

Amphibians are undergoing global-scale declines due to the increased incidence of anthropogenic stressors. The loss of species with unique evolutionary histories and functional traits poses a serious risk to the maintenance of ecosystem functions in aquatic environments, already directly affected by several anthropogenic land-use changes. Here, we investigated the influence of anthropogenic stressors (roads and Pinus monocultures) on functional, phylogenetic and taxonomic composition and functional dispersion of an anuran metacommunity of 33 ponds in southern Brazil. We expected for the relative influence of anthropogenic stressors to vary according to the compositional facet, with a greater influence of these stressors on the functional and phylogenetic than on the taxonomic facet. We also expected traits related to habitat exploration (head shape and eye size and position) to be more influenced by Pinus monocultures, while the traits related to the dispersion and the physiological control of individuals (limb length and body mass) to be similarly influenced by roads and Pinus. To evaluate this, we used PERMANOVA analyses for each of the compositional facets and anthropogenic stressor, and path models to verify all possible relationships between patterns of functional dispersion and anthropogenic stressors. We found that, while the distance from ponds to Pinus monocultures influences the phylogenetic composition, distance to roads influences the functional composition; distance to roads affects mostly the functional dispersion of the communities. These anthropogenic stressors affect the structure of anuran communities, even those formed by generalist species in terms of habitat use. There is a decline in diversity in communities located close to Pinus and roads, leading to losses in the evolutionary history accumulated in these communities. The control of vehicle traffic during reproduction periods and the maintenance of areas with natural vegetation, particularly around ponds, may help mitigate the negative effects of anthropogenic stressors on anuran communities.

ecology↗

bioRxiv2020

Predator morphology affects prey consumption: evidence from an anuran population in subtropical wetlands

Morphology and diet are key factors in the ecology of organisms, determining aspects of natural history and evolution of the species. In this work, we evaluated the diet-morphology relationship in an anuran population, measuring the influence of morphological traits on the variation in the diet of individuals of Leptodactylus latrans. For this purpose, we collected individuals from a natural grassland habitat in southern Brazil. We analyzed the stomach content of individuals and consumed food items were classified up to the level of order. We also measured four morphological traits per individual of L. latrans: snout-vent length, relative limb length, distance between eyes and relative mouth width. We applied Linear Mixed Effect Models to evaluate the relationship of anuran morphological traits, number of prey taxa and volume of consumed prey. We tested the hypothesis that the configuration of predator morphological traits determines both the number of taxa and the volume of consumed prey. Our results indicate that individuals of L. latrans with larger body size consume a larger volume of prey and mouth width is directly and positively associated with the number of consumed taxa. In the same way that body size seems to define the capacity to ingest a large number of prey items, mouth width could be a limiting factor in prey selection. The capacity to consume a large prey volume could be an advantage in unpredictable environments, especially those with great daily thermal amplitudes such as the subtropical Brazilian grasslands.

ecology↗

bioRxiv2020

What and When Local Predictors Drive Tadpole Diversity in Subtropical Temporary Ponds?

We evaluated seasonal variation in taxonomic, functional and phylogenetic diversity and redundancy of tadpoles in 401 points of 10 ponds in southern Brazil. We predicted i) congruent patterns between all components of diversity and environmental descriptors; ii) stronger effects of environment in the diversity components in seasons when the water level in ponds is low; iii) diversity components to be influenced by distinct sets of environmental factors in different periods. Predictions were tested using Linear Mixed Models. We observed positive influence of water depth on taxonomic, functional and phylogenetic diversity, as well as on functional redundancy during periods when the water level in ponds is high. Phylogenetic redundancy was not explained by any of the selected environmental variables. When the water level in ponds is low none of the environmental descriptors affects any of the diversity components. Environmental filtering seems to strongly influence tadpole community structure in temporary ponds, at least in periods when water depth gradients create a variety of micro-habitats allowing diverse sets of species to settle and co-occur. These species sets are then filtered according to their swimming and foraging abilities along the depth gradient, where intermediate depths should contain the greatest tadpole diversity.

ecology↗

bioRxiv2020

TURNOVER OR INTRASPECIFIC TRAIT VARIATION: EXPLAINING FUNCTIONAL VARIABILITY IN A NEOTROPICAL ANURAN METACOMMUNITY

Trait variation across environmental gradients results from two processes: intraspecific variation (ITV) and turnover. Tadpoles are known to exhibit phenotypic plasticity in several traits in response to the environment, resulting from intra or interspecific variation. Here we evaluate patterns of intraspecific variation in functional traits of adult anurans (head shape, eye size and position, limb length and body mass) and their relationship with environmental variables in an anuran metacommunity in southern Brazil. From anurans sampled from 33 ponds, we decomposed trait variation into ITV and turnover and modelled trait-environment relationships. We predict that the contribution of ITV and turnover to trait variation and trait-environment relationships should vary according to the preferred habitat of the species and the analysed traits. Intraspecific variation accumulated the highest rate of trait variation for arboreal species, while interspecific variation was greater for aquatic-terrestrial species and for the whole set of species. The contributions of turnover and ITV to shifts in community mean trait values were similar between traits, but differed between species sets. Depth, distance between ponds, area of Pinus surrounding the ponds, and types of pond vegetation and substrate strongly influenced trait variation, but their relative contribution depended on the analysed traits and species sets. The great contribution of ITV for head shape and eye size and position suggests the existence of intraspecific adaptations to microhabitats, while turnover dominance in the variation of body mass and limb length suggests differences in dispersal and trophic segregation between species.

ecology↗

bioRxiv2019

Taxonomic and functional anuran beta diversity of the subtropical metacommunity respond differentially to environmental and spatial predictors

The relative contributions of environmental and spatial predictors in the patterns of taxonomic and functional anuran beta diversity were examined in 33 ponds of a metacommunity along the coast of south Brazil. Anurans exhibit limited dispersion ability and have physiological and behavioural characteristics that narrow their relationships with both environmental and spatial predictors. So, we expected that neutral processes and, in particular, niche-based processes could have similar influence on the taxonomic and functional beta diversity patterns. Variation partitioning and distance-based methods (db-RDA) were conducted with presence/absence and abundance data to examine taxonomic and functional facets and components (total, turnover and nestedness-resultant) in relation to environmental and spatial predictors. Processes determining metacommunity structure were similar between the components of beta diversity but differed among taxonomic and functional diversity. While taxonomic beta diversity was further accounted by environmental predictors, functional beta diversity responded more strongly to spatial predictors. These patterns were more evident when assessed through abundance data. These opposing patterns were contrary to what we had predicted, suggesting that while there is a taxonomic turnover mediated by environmental filters, the spatial distance promotes the trait dissimilarity between sites. Our results reinforce the idea that studies aiming to evaluate the patterns of structure in metacommunities should include different facets of diversity so that better interpretations can be achieved.

ecology↗