Find research datasets worth reusing

Data from: Progressively excluding mammals of different body size affects community and trait structure of ground beetles

Mammalian grazing induces changes in vegetation properties in grasslands, which can affect a wide variety of other animals including many arthropods. However, the impacts may depend on the type and body size of these mammals. Furthermore, how mammals influence functional trait syndromes of arthropod communities is not well known. We progressively excluded large (e.g. red deer, chamois), medium (e.g. alpine marmot, mountain hare), and small (e.g. mice) mammals using size-selective fences in two vegetation types (short- and tall-grass vegetation) of subalpine grasslands. We then assessed how these exclusions affected the community composition and functional traits of ground beetles (Coleoptera, Carabidae), and which vegetation characteristic mediated the observed effects. Total carabid biomass, the activity densities of carabids with specific traits (i.e. small eyes, short wings), the richness of small-eyed species and the richness of herbivorous species were significantly higher when certain mammals were excluded compared to when all mammals had access, regardless of vegetation type. Excluding large and medium mammals increased the activity density of herbivorous carabid species, but only in short-grass vegetation. Similarly, excluding large mammals (ungulates) altered carabid species composition in the short-, but not in the tall-grass vegetation. All these responses were related to aboveground plant biomass, but not to plant Shannon diversity or vegetation structural heterogeneity. Our results indicate that changes in aboveground plant biomass are key drivers of mammalian grazers' influence on carabids, suggesting that bottom-up forces are important in subalpine grassland systems. The exclusion of ungulates provoked the strongest carabid response. Our results, however, also highlight the ecological significance of smaller herbivorous mammals. Our study furthermore shows that mammalian grazing not only altered carabid community composition, but also caused community-wide functional trait shifts, which could potentially have a wider impact on species interactions and ecosystem functioning.

opencc-zeroDec 2014View details →

Data from: Experimental manipulation of avian social structure reveals segregation is carried over across contexts

Our current understanding of animal social networks is largely based on observations or experiments that do not directly manipulate associations between individuals. Consequently, evidence relating to the causal processes underlying such networks is limited. By imposing specified rules controlling individual access to feeding stations, we directly manipulated the foraging social network of a wild bird community, thus demonstrating how external factors can shape social structure. We show that experimentally imposed constraints were carried over into patterns of association at unrestricted, ephemeral food patches, as well as at nesting sites during breeding territory prospecting. Hence, different social contexts can be causally linked, and constraints at one level may have consequences that extend into other aspects of sociality. Finally, the imposed assortment was lost following the cessation of the experimental manipulation, indicating the potential for previously perturbed social networks of wild animals to recover from segregation driven by external constraints.

opencc-zeroJul 2019View details →

Data from: The influence of fire frequency on the structure and botanical composition of savanna ecosystems

Savannas cover 60% of the land surface in Southern Africa, with fires and herbivory playing a key role in their ecology. The Limpopo National Park (LNP) is a 10,000 km2 conservation area in southern Mozambique and key to protecting savannas in the region. Fire is an important factor in LNP's landscapes, but little is known about its role in the park's ecology. In this study, we explored the interaction between fire frequency (FF), landscape and vegetation. To assess the FF, we analysed ten years of the MODerate resolution Imaging Spectroradiometer (MODIS) burned area product (2003-2013). A stratified-random sampling approach was used to assess biodiversity across three dominant landscapes (Nwambia Sandveld-NS, Lebombo North-LN and Shrubveld Mopane on Calcrete-C) and two FF levels (low - twice or less; and high - 3 times or more, during 10 years). Six ha were sampled in each stratum, except for the LN vs High FF in which low accessibility allowed only 3 ha sampling. FF was higher in NS and LN landscapes, where 25% and 34% of the area, respectively burned more than three times in 10 years. The landscape type was the main determinant of grass composition and biomass. However, in the sandy NS biomass was higher under high FF. The three landscapes supported three different tree/shrub communities, but FF resulted in compositional variations in NS and LN. Fire frequency had no marked influence on woody structural parameters (height, density and phytomass). We concluded that the savannas in LNP are mainly driven by landscape (geology), but FF may impose specific modifications. We recommend a fire laissez-faire management system for most of the park and a long-term monitoring system of vegetation to address vegetation changes related to fire. Fire management should be coordinated with the neighboring Kruger National Park, given its long history of fire management.

Data from: Foraging impacts of Asian megafauna on tropical rainforest structure and biodiversity

Megaherbivores are known to influence the structure, composition, and diversity of vegetation. In Central Africa, forest elephants act as ecological filters by breaking tree saplings and stripping them of foliage. Much less is known about impacts of megafauna on Southeast Asian rain forests. Here, we ask whether herbivory by Asian megafauna has impacts analogous to those of African forest elephants. To answer this, we studied forest (1) structure, (2) composition, (3) diversity, and (4) tree scars in Belum and Krau, two protected areas of Peninsular Malaysia, and compared the results with those obtained in African forests. Elephants are abundant in Belum but have been absent in Krau since 1993. We found that stem density and diversity, especially of tree saplings, were higher in Krau than in Belum. Palms and other monocots were also more abundant in Krau. In Belum, however, small monocots (<1 m tall) were very abundant but larger ones (>1 m tall) were virtually absent, suggesting size-selective removal. The frequency of stem-break scars was equal at Belum and Krau but less than in Central Africa and greater than in the Peruvian Amazon where tapirs are the only megafauna. Pigs and tapirs could also contribute to the high frequency of tree scars recorded in Malaysian forests. Forest-dwelling elephants in Asia seem to have a reduced impact on tree saplings compared to African forest elephants, but a very strong impact on monocots.

opencc-zeroDec 2013View details →

Data from: Do intraspecific or interspecific interactions determine responses to predators feeding on a shared size-structured prey community?

1. Coexistence of predators that share the same prey is common. This is still the case in size structured predator communities where predators consume prey species of different sizes (interspecific prey responses) or consume different size classes of the same species of prey (intraspecific prey responses). 2. A mechanism has recently been proposed to explain coexistence between predators that differ in size but share the same prey species, emergent facilitation, which is dependent on strong intraspecific responses from one or more prey species. Under emergent facilitation predators can depend on each other for invasion, persistence or success in a size structured prey community. 3. Experimental evidence for intraspecific size-structured responses in prey populations remain rare and further questions remain about direct interactions between predators that could prevent or limit any positive effects between predators (e.g. intraguild predation). 4. Here we provide a community wide experiment on emergent facilitation including natural predators. We investigate both the direct interaction between two predators that differ in body size (fish vs. invertebrate predator) and the indirect interaction between them via their shared prey community (zooplankton). 5. Our evidence supports the most likely expectation of interactions between differently sized predators, that intraguild predation rates are high and interspecific interactions in the shared prey community dominate the response to predation (i.e. predator-mediated competition). The question of whether emergent facilitation occurs frequently in nature requires more empirical and theoretical attention, specifically to address the likelihood that its pre-conditions may co-occur with high rates of intraguild predation.

opencc-zeroDec 2012View details →

Data from: Deciphering the fine-structure of tribal admixture in the Bedouin population using genomic data

The Bedouin Israeli population is highly inbred and structured with a very high prevalence of recessive diseases. Many studies in the past two decades focused on linkage analysis in large, multiple consanguineous pedigrees of this population. The advent of high-throughput technologies motivated researchers to search for rare variants shared between smaller pedigrees, integrating data from clinically similar yet seemingly non-related sporadic cases. However, such analyses are challenging because, without pedigree data, there is no prior knowledge regarding possible relatedness between the sporadic cases. Here, we describe models and techniques for the study of relationships between pedigrees and use them for the inference of tribal co-ancestry, delineating the complex social interactions between different tribes in the Negev Bedouins of southern Israel. Through our analysis, we differentiate between tribes that share many yet small genomic segments because of co-ancestry versus tribes that share larger segments because of recent admixture. The emergent pattern is well correlated with the prevalence of rare mutations in the different tribes. Tribes that do not intermarry, mostly because of social restrictions, hold private mutations, whereas tribes that do intermarry demonstrate a genetic flow of mutations between them. Thus, social structure within an inbred community can be delineated through genomic data, with implications to genetic counseling and genetic mapping.

opencc-zeroDec 2015View details →

Data from: Climate-related adaptive genetic variation and population structure in natural stands of Norway spruce in the South-Eastern Alps

Forest trees dominate many Alpine landscapes that are currently exposed to changing climate. Norway spruce is one of the most important conifer species of the Italian Alps, and natural populations are found across steep environmental gradients with large differences in temperature and moisture availability. This study seeks to determine and quantify patterns of genetic diversity in natural populations toward understanding adaptive responses to changing climate. Across the Italian species range, 24 natural stands were sampled with a major focus on the Eastern Italian Alps. Sampled trees were genotyped for 384 selected single nucleotide polymorphisms (SNPs) from 285 genes. A wide array of potential candidate genes was tested for correlation with climatic parameters. To minimize false-positive association between genotype and climate, population structure was investigated. Pairwise F ST estimates between sampled populations ranged between 0.000 and 0.075, with the highest values involving the two disjoint populations, Valdieri, on the western Italian Alps, and Campolino, the most southern population on the Apennines. Despite considerable genetic admixture among populations, both Bayesian and multivariate approach identified four genetic clusters. Selection scans revealed five F ST outliers, and the environmental association analysis detected ten SNPs associated to one or more climatic variables. Overall, 13 potentially adaptive loci were identified, three of which have been reported in a previous study on the same species conducted on a broader geographical scale. In our study, precipitation, more than temperature, was often associated with genotype; therefore, it appears as the most important environmental variable associated with the high sensitivity of Norway spruce to soil water supply. These findings provide relevant information for understanding and quantifying climate change effects on this species and its ability to genetically adapt.

opencc-zeroDec 2013View details →

Data from: Highly resolved early Eocene food webs show development of modern trophic structure after the end-Cretaceous extinction

Generalities of food web structure have been identified for extant ecosystems. However, the trophic organization of ancient ecosystems is unresolved, as prior studies of fossil webs have been limited by low-resolution, high-uncertainty data. We compiled highly resolved, well-documented feeding interaction data for 700 taxa from the 48 million-year-old latest early Eocene Messel Shale, which contains a species assemblage that developed after an interval of protracted environmental and biotal change during and following the end-Cretaceous extinction. We compared the network structure of Messel lake and forest food webs to extant webs using analyses that account for scale dependence of structure with diversity and complexity. The Messel lake web, with 94 taxa, displays unambiguous similarities in structure to extant webs. While the Messel forest web, with 630 taxa, displays differences compared to extant webs, they appear to result from high diversity and resolution of insect–plant interactions, rather than substantive differences in structure. The evidence presented here suggests that modern trophic organization developed along with the modern Messel biota during an 18 Myr interval of dramatic post-extinction change. Our study also has methodological implications, as the Messel forest web analysis highlights limitations of current food web data and models.

opencc-zeroDec 2012View details →

Data from: Population structure of the Chagas disease vector, Triatoma infestans, at the urban-rural interface

The increasing rate of biological invasions resulting from human transport or human-mediated changes to the environment have had devastating ecologic and public health consequences. The kissing bug, Triatoma infestans, has dispersed through the Peruvian city of Arequipa. The biological invasion of this insect has resulted in a public health crisis, putting thousands of residents of this city at risk of infection by Trypanosoma cruzi and subsequent development of Chagas disease. Here we show that populations of Tria. infestans in geographically distinct districts within and around this urban center share a common recent evolutionary history although current gene flow is restricted even between proximal sites. The population structure among the Tria. infestans in different districts is not correlated with the geographic distance between districts. These data suggest that migration among the districts is mediated by factors beyond the short-range migratory capabilities of Tria. Infestans and that human movement has played a significant role in the structuring of the Tria. infestans population in the region. Rapid urbanization across southern South America will continue to create suitable environments for Tria. infestans and knowledge of its urban dispersal patterns may play a fundamental role in mitigating human disease risk.

Data from: Comparative assessment of SSR and SNP markers for inferring the population genetic structure of the common fungus Armillaria cepistipes

During the last years, simple sequence repeats (SSRs, also known as microsatellites) and single-nucleotide polymorphisms (SNPs) have become the most popular molecular markers for describing neutral genetic variation in populations of a wide range of organisms. However, only a limited number of studies has focused on comparing the performance of these two types of markers for describing the underlying genetic structure of wild populations. Moreover, none of these studies targeted fungi, the group of organisms with one of the most complex reproductive strategies. We evaluated the utility of SSRs and SNPs for inferring the neutral genetic structure of Armillaria cepistipes (basidiomycetes) at different spatial scales. For that, 407 samples were collected across a small (150 km2) area in the Ukrainian Carpathians and a large (41 000 km2) area in the Swiss Alps. All isolates were analyzed at 17 SSR loci distributed throughout the whole genome and at 24 SNP loci located in different single-copy conserved genes. The two markers showed different patterns of structure within the two spatial scales studied. The multi-allelic SSR markers seemed to be best suited for detecting genetic structure in indigenous fungal populations at a rather small spatial scale (radius of ~50-100 km). The pattern observed at SNP markers rather reflected ancient divergence of distant (~1000 km) populations that in addition are separated by mountain ranges. Despite these differences, both marker types were suitable for detecting the weak genetic structure of the two A. cepistipes populations investigated.

Data from: Leaf litter diversity and structure of microbial decomposer communities modulate litter decomposition in aquatic systems

1. Leaf litter decomposition is a major ecosystem process that can link aquatic to terrestrial ecosystems by flows of nutrients. Biodiversity and ecosystem functioning research hypothesizes that the global loss of species leads to impaired decomposition rates and thus to slower recycling of nutrients. Especially in aquatic systems an understanding of diversity effects on litter decomposition is still incomplete. 2. Here we conducted an experiment to test two main factors associated with global species loss that might influence leaf litter decomposition. Firstly, we tested whether mixing different leaf species alters litter decomposition rates compared to decomposition of these species in monoculture. Secondly, we tested the effect of the size structure of a lotic decomposer community on decomposition rates. 3. Overall, leaf litter identity strongly affected decomposition rates, and the observed decomposition rates matched measures of metabolic activity and microbial abundances. While we found some evidence of a positive leaf litter diversity effect on decomposition, this effect was not coherent across all litter combinations and the effect was generally additive and not synergistic. 4. Microbial communities, with a reduced functional and trophic complexity, showed a small but significant overall reduction in decomposition rates compared to communities with the naturally complete functional and trophic complexity, highlighting the importance of a complete microbial community on ecosystem functioning. 5. Our results suggest that top-down diversity effects of the decomposer community on litter decomposition in aquatic systems are of comparable importance as bottom-up diversity effects of primary producers.

opencc-zeroDec 2015View details →

Data from: Manifold influences of phylogenetic structure on a plant-herbivore network

Ecologists are increasingly aware of the interplay between evolutionary history and ecological processes in shaping current species interaction patterns. The inclusion of phylogenetic relationships in studies of species interaction networks has shown that closely related species commonly interact with sets of similar species. Notably, the degree of phylogenetic conservatism in antagonistic ecological interactions is frequently stronger among species at lower trophic levels than among those at higher trophic levels. One hypothesis that accounts for this asymmetry is that competition among consumer species promotes resource partitioning and offsets the maintenance of dietary similarity by phylogenetic inertia. Here, we used a regional plant-herbivore network comprised of Asteraceae species and flower-head endophagous insects to evaluate how the strength of phylogenetic conservatism in species interactions differs between the two trophic levels. We also addressed whether the asymmetry in the strength of the phylogenetic signal between plants and animals depends on the overall degree of relatedness among the herbivores. We show that, beyond the previously reported compositional similarity, closely related species also share a greater proportion of counterpart phylogenetic history, both for resource and consumer species. Comparison of the patterns found in the entire network with those found in subnetworks composed of more phylogenetically restricted groups of herbivores provides evidence that resource partitioning occurs mostly at deeper phylogenetic levels, so that a positive phylogenetic signal in antagonist similarity is detectable even between closely related consumers in monophyletic subnetworks. The asymmetry in signal strength between trophic levels is most apparent in the way network modules reflect resource phylogeny, both for the entire network and for subnetworks. Taken together, these results suggest that evolutionary processes, such as phylogenetic conservatism and independent colonization history of the insect groups may be the main forces generating the phylogenetic structure observed in this particular plant–herbivore network system.

opencc-zeroDec 2018View details →

Data from: Pleistocene climate change and phylogeographic structure of the Gymnocarpos przewalskii (Caryophyllaceae) in the northwest China: Evidence from plastid DNA, ITS sequences, and Microsatellite

Northwestern China has a wealth of endemic species, which has been hypothesized to be affected by the complex paleoclimatic and paleogeographic history during Quaternary. In this paper, we used Gymnocarpos przewalskii as a model to address the evolutionary history and current population genetic structure of species in northwestern China. We employed two chloroplast DNA fragments (rps16 and psbB‐psbI), one nuclear DNA fragment (ITS), and simple sequence repeat (SSRs) to investigate the spatial genetic pattern of G. przewalskii. High genetic diversity (cpDNA: hS = 0.330, hT = 0.866; ITS: hS = 0.458, hT = 0.872) was identified in almost all populations, and most of the population have private haplotypes. Moreover, multimodal mismatch distributions were observed and estimates of Tajima's D and Fu's FS tests did not identify significantly departures from neutrality, indicating that recent expansion of G. przewalskii was rejected. Thus, we inferred that G. przewalskii survived generally in northwestern China during the Pleistocene. All data together support the genotypes of G. przewalskii into three groups, consistent with their respective geographical distributions in the western regions—Tarim Basin, the central regions—Hami Basin and Hexi Corridor, and the eastern regions—Alxa Desert and Wulate Prairie. Divergence among most lineages of G. przewalskii occurred in the Pleistocene, and the range of potential distributions is associated with glacial cycles. We concluded that climate oscillation during Pleistocene significantly affected the distribution of the species.

opencc-zeroDec 2019View details →

Data from: Forest structure and snow depth alter the movement patterns and subsequent expenditures of a forest carnivore, the Pacific marten

<p>Energetic balance is central to the survival and persistence of free-ranging animals. Quantifying expenditures and identifying factors that drive energetics informs our understanding of species' ecology and their responses to shifting environmental conditions. Approaches used to estimate energetic expenditures of free-ranging species, such as doubly-labelled water (DLW), are precise but difficult to implement. Global positioning system (GPS) collars and accelerometers have emerged as alternatives for estimating expenditures, but these techniques have few applications in terrestrial species and no applications in small-bodied (<5kg) terrestrial animals. Here, we estimated movement characteristics and field metabolic rates (FMR) of Pacific martens (Martes caurina), a small-bodied carnivore with relatively high energetic costs, in a heterogeneous landscape to explore the role of movement and landscape characteristics on energetics. We concurrently used DLW and GPS collars to investigate the relationship between movement characteristics and FMR. Movement velocity explained the greatest amount of variation in mass-specific FMR and we used this relationship to predict expenditures of previously collared martens. We found that predicted mass-specific FMR was highest among males and increased in open patches primarily as a result of increased velocity and more erratic movements. Additionally, martens moving through deep snow also exhibited increased FMR. Our work shows movement metrics can effectively explain variation in FMR and identify landscape features, like forest structure and snow depth, that influence movements with cascading effects on energetics for free-ranging mammals in rapidly changing systems.</p>

Data from: Melanization of mycorrhizal fungal necromass structures microbial decomposer communities

Mycorrhizal fungal necromass is increasingly recognized as an important contributor to soil organic carbon pools, particularly in forest ecosystems. While its decomposition rate is primarily determined by biochemical composition, how traits such as melanin content affect the structure of necromass decomposer communities remains poorly understood. To assess the role of biochemical traits on microbial decomposer community composition and functioning, we incubated melanized and non-melanized necromass of the mycorrhizal fungus Meliniomyces bicolor in Pinus- and Quercus-dominated forests in Minnesota, USA and then assessed the associated fungal and bacterial decomposer communities after 1, 2 and 3 months using high-throughput sequencing. Melanized necromass decomposed significantly slower than non-melanized necromass in both forests. The structure of the microbial decomposer communities depended significantly on necromass melanin content, although the effect was stronger for fungi than bacteria. On non-melanized necromass, fungal communities were dominated by r-selected ascomycete and mucoromycete microfungi early and then replaced by basidiomycete ectomycorrhizal fungi, while on melanized necromass these groups were co-dominant throughout the incubation. Bacterial communities were dominated by both specialist mycophageous and generalist taxa. Synthesis. Our results indicate that necromass biochemistry not only strongly affects rates of decomposition but also the structure of the associated decomposer communities. Furthermore, the observed colonization patterns suggest that fungi, and particularly ectomycorrhizal fungi, may play a more important role in necromass decomposition than previously recognized.

Data from: AFLP diversity and spatial structure of Calycophyllum candidissimum (Rubiaceae), a dominant tree species of Nicaragua's critically endangered seasonally dry forest

The Central American seasonally dry tropical (SDT) forest biome is one of the worlds' most endangered ecosystems, yet little is known about the genetic consequences of its recent fragmentation. A prominent constituent of this biome is Calycophyllum candidissimum, an insect-pollinated and wind-dispersed canopy tree of high socio-economic importance, particularly in Nicaragua. Here, we surveyed amplified fragment length polymorphisms across 13 populations of this species in Nicaragua to elucidate the relative roles of contemporary vs historical factors in shaping its genetic variation. Genetic diversity was low in all investigated populations (mean HE=0.125), and negatively correlated with latitude. Overall population differentiation was moderate (ΦST=0.109, P<0.001), and Bayesian analysis of population structure revealed two major latitudinal clusters (I: 'Pacific North'+'Central Highland'; II: 'Pacific South'), along with a genetic cline between I and II. Population-based cluster analyses indicated a strong pattern of 'isolation by distance' as confirmed by Mantel's test. Our results suggest that (1) the low genetic diversity of these populations reflects biogeographic/population history (colonisation from South America, Pleistocene range contractions) rather than recent human impact; whereas (2) the underlying process of their isolation by distance pattern, which is best explained by 'isolation by dispersal limitation', implies contemporary gene flow between neighbouring populations as likely facilitated by the species' efficient seed dispersal capacity. Overall, these results underscore that even tree species from highly decimated forest regions may be genetically resilient to habitat fragmentation due to species-typical dispersal characteristics, the necessity of broad-scale measures for their conservation notwithstanding.

opencc-zeroAug 2019View details →

Data from: Comprehensive evaluation of genetic population structure for anadromous river herring with single nucleotide polymorphism data

Anthropogenic activities are placing increasing pressure on many species, particularly those that rely on more than one ecosystem. River herring (alewife, Alosa pseudoharengus and blueback herring, A. aestivalis collectively) are anadromous fishes that reproduce in rivers and streams of eastern North America and migrate to the western Atlantic Ocean. Here, we use data from single nucleotide polymorphisms (SNPs) to provide a comprehensive analysis of population structure for both species of river herring throughout their native ranges. We sampled river herring spawning runs in rivers from Newfoundland to Florida, examining a total of 108 locations, and genotyping over 8000 fish. We identified geographic population groupings (regional genetic groups) in each species, as well as significant genetic differentiation between most populations and rivers. Strong correlations between geographic and genetic distances (i.e., isolation by distance) were found range-wide for both species, although the patterns were less consistent at smaller spatial scales. River herring are caught as bycatch in fisheries and estimating stock proportions in mixed fishery samples is important for management. We assessed the utility of the SNP datasets as reference baselines for genetic stock identification. Results indicated high accuracy of individual assignment (76–95%) to designated regional genetic groups, and some individual populations, as well as highly accurate estimates of mixing proportions for both species. This study is the first to evaluate genetic structure across the entire geographic range of these species and provides an important foundation for conservation and management planning. The SNP reference datasets will facilitate continued multi-lateral monitoring of bycatch, as well as ecological investigation to provide information about ocean dispersal patterns of these species.

Data from: A test of the eavesdropping avoidance hypothesis as an explanation for the structure of low amplitude aggressive signals in the song sparrow

Low amplitude signals function in private exchanges of information between signalers and nearby receivers. The eavesdropping avoidance hypothesis proposes that selection favors quiet threat signals in order to avoid the costs of eavesdroppers. If true, then selection should favor other acoustic traits in addition to low amplitude that lead to quiet signals transmitting less effectively through the environment compared to broadcast signals. The "warbled" soft songs of male song sparrows differ from "crystallized" soft songs and from broadcast songs in a number of acoustic traits, suggesting that these songs may transmit less effectively. We tested this prediction in a field experiment by playing broadcast songs, crystallized soft songs, and warbled soft songs through a loudspeaker at the same amplitude and recording the propagated songs at five distances, at two heights, and in two different habitat types. Counter to our prediction, we found no evidence that either form of soft song transmits differently than broadcast song when all were played loudly. If anything, soft songs transmitted more effectively when all songs were played quietly. Our results do not support one prediction made by the eavesdropping avoidance hypothesis, although the possibility remains that reduced amplitude alone is sufficient to reduce eavesdropping. The question of why warbled soft song differs in acoustic structure remains unresolved.

Data from: Genetic diversity and population structure of Varronia curassavica: a medicinal polyploid species in a threatened ecosystem

Varronia curassavica is an important medicinal species associated with the restinga, one of the most threatened coastal ecosystems of the Atlantic Forest. These circumstances call for studies aimed at estimating effective population size and gene flow to improve conservation efforts. Hence, the present study aimed to characterize the genetic diversity, ploidy level and population structure of this species in different areas of restinga using microsatellites. Varronia curassavica was characterized as an autotetraploid, with high genetic variability, low divergence, and no significant fixation indices, indicating the absence of, or reduced, inbreeding and genetic drift in the study area. About 44 % of the alleles occurred at low frequency in adults of all populations and 41 % in the progenies evaluated. Gene flow was high, consistent with outcrossing species with high dispersal capacity (Nm = 4.87). The results showed no tendency toward isolation by distance. The estimated effective size indicates that the populations studied have the potential to ensure conservation of the species in the long term. The genetic variability and population structure of V. curassavica, as determined in this study, could form the foundation for activities directed toward the sustainable use of this resource and its conservation. Even though the restinga ecosystem has suffered dramatic reductions in area, this study provides evidence that this species is resilient to anthropogenic threats to its genetic integrity, since it is a polyploid with self-incompatibility mechanisms that contribute to maintaining high genetic diversity in an panmictic meta-population along the coast of Santa Catarina.

Data from: Lake regionalization and diatom metacommunity structuring in tropical South America

Lakes and their topological distribution across Earth's surface impose ecological and evolutionary constraints on aquatic metacommunities. In this study, we group similar lake ecosystems as metacommunity units influencing diatom community structure. We assembled a database of 195 lakes from the tropical Andes and adjacent lowlands (8ºN–30ºS and 58–79ºW) with associated environmental predictors to examine diatom metacommunity patterns at two different levels: taxon and functional (deconstructed species matrix by ecological guilds). We also derived spatial variables that inherently assessed the relative role of dispersal. Using complementary multivariate statistical techniques (Principal Component Analysis, cluster analysis, non-metric multidimensional scaling, Procrustes, variance partitioning), we examined diatom-environment relationships among different lake habitats (sediment surface, periphyton and plankton) and partitioned community variation to evaluate the influence of niche- and dispersal-based assembly processes in diatom metacommunity structure across lake clusters. The results showed a significant association between geographic clusters of lakes based on gradients of climate and landscape configuration and diatom assemblages. Six lake clusters distributed along a latitudinal gradient were identified as functional metacommunity units for diatom communities. Variance partitioning revealed that dispersal mechanisms were a major contributor to diatom metacommunity structure, but in a highly context-dependent fashion across lake clusters. In the Andean Altiplano and adjacent lowlands of Bolivia, diatom metacommunities are niche assembled but constrained by either dispersal limitation or mass effects, resulting from area, environmental heterogeneity, and ecological guild relationships. Topographic heterogeneity played an important role in structuring planktic diatom metacommunities. We emphasize the value of a guild-based metacommunity model linked to dispersal for elucidating mechanisms underlying latitudinal gradients in distribution. Our findings reveal the importance of shifts in ecological drivers across climatic and physiographically distinct lake clusters, providing a basis for comparison of broad-scale community gradients in lake-rich regions elsewhere. This may help guide future research to explore evolutionary constraints on the rich Neotropical benthic diatom species pool.