Greater Dispersal Ability Research Articles

Testing the efficacy of different molecular tools for parasite conservation genetics: a case study using horsehair worms (Phylum: Nematomorpha).

In recent years, parasite conservation has become a globally significant issue. Because of this, there is a need for standardized methods for inferring population status and possible cryptic diversity. However, given the lack of molecular data for some groups, it is challenging to establish procedures for genetic diversity estimation. Therefore, universal tools, such as double-digest restriction-site-associated DNA sequencing (ddRADseq), could be useful when conducting conservation genetic studies on rarely studied parasites. Here, we generated a ddRADseq dataset that includes all 3 described Taiwanese horsehair worms (Phylum: Nematomorpha), possibly one of the most understudied animal groups. Additionally, we produced data for a fragment of the cytochrome c oxidase subunit I (COXI) for the said species. We used the COXI dataset in combination with previously published sequences of the same locus for inferring the effective population size (Ne) trends and possible population genetic structure.We found that a larger and geographically broader sample size combined with more sequenced loci resulted in a better estimation of changes in Ne. We were able to detect demographic changes associated with Pleistocene events in all the species. Furthermore, the ddRADseq dataset for Chordodes formosanus did not reveal a genetic structure based on geography, implying a great dispersal ability, possibly due to its hosts. We showed that different molecular tools can be used to reveal genetic structure and demographic history at different historical times and geographical scales, which can help with conservation genetic studies in rarely studied parasites.

Traits shaping urban tolerance in birds differ around the world

As human density increases, biodiversity must increasingly co-exist with urbanization or face local extinction. Tolerance of urban areas has been linked to numerous functional traits, yet few globally consistent patterns have emerged to explain variation in urban tolerance, which stymies attempts at a generalizable predictive framework. Here, we calculate an Urban Association Index (UAI) for 3,768 bird species in 137 cities across all permanently inhabited continents. We then assess how this UAI varies as a function of ten species-specific traits and further test whether the strength of trait relationships vary as a function of three city-specific variables. Of the ten species traits, nine were significantly associated with urban tolerance. Urban-associated species tend to be smaller, less territorial, have greater dispersal ability, broader dietary and habitat niches, larger clutch sizes, greater longevity, and lower elevational limits. Only bill shape showed no global association with urban tolerance. Additionally, the strength of several trait relationships varied across cities as a function of latitude and/or human population density. For example, the associations of body mass and diet breadth were more pronounced at higher latitudes, while the associations of territoriality and longevity were reduced in cities with higher population density. Thus, the importance of trait filters in birds varies predictably across cities, indicating biogeographic variation in selection for urban tolerance that could explain prior challenges in the search for global patterns. A globally informed framework that predicts urban tolerance will be integral to conservation as increasing proportions of the world's biodiversity are impacted by urbanization.

Competition–colonisation trade‐offs are found among but not within wind‐dispersed Pinus species

Abstract The competition–colonisation trade‐off is recognised as a key mechanism for diversity maintenance, whereby weak competitors can avoid competition with stronger competitors due to their greater dispersal ability. To date, most theoretical and empirical work has focused on trade‐offs among different species yet a within‐species perspective is crucial to assess the scope for natural selection on competition–colonisation trade‐offs. For six wind‐dispersed Pinus species encompassing a wide range of seed masses, we examined whether within and among species there was evidence that heavier seeds typically disperse shorter distances but produce seedlings that are stronger competitors with a higher likelihood of successful establishment, under different treatment conditions. Within species, we found seedling establishment to be independent of diaspore terminal velocity (a measure of dispersal potential), which would maximise the variation in potential dispersal distances and locations reached by the seeds shed from a parent tree, and therefore the chances that some offspring will reach a favourable recruitment site. However, among Pinus species the likelihood of seedling emergence and survival was higher in species that produce heavier seeds with higher terminal velocity. We found a marked competition–colonisation trade‐off among all six species consistent with expectations from coexistence theory. In contrast, within species, there was no evidence of competition–colonisation trade‐offs for any species, despite differences in the relationships between diaspore mass and terminal velocity. This is consistent with weak selection within species for a competition–colonisation trade‐off. The results suggest that within‐species trade‐offs do not influence the risk of invasive spread. A free Plain Language Summary can be found within the Supporting Information of this article.

Simulation-Based Investigation of the Performance of Delimiting Trapping Surveys for Insect Pests.

Fully trapped survey designs are widely used to delimit adventive pests populations that can be detected using traps and lures. Delimitation includes verifying the presence of the pest and determining its spatial extent. The size and shape of the survey design and the density of traps can vary; however, resulting variation in detecting efficiency is often unknown. We used a trapping network simulation model with diffusion-based insect movement to investigate delimiting survey trapping design performance for fully trapped and some modified designs. Simulations included randomized outbreak locations in a core area and a duration of 30 d. We assessed impacts of insect dispersal ability, grid size and shape, and trap attractiveness and density on survey performance, measured as mean probability of capturing individual pests [p(capture)]. Most published grids are square, but circles performed equally well and are more efficient. Over different grid sizes, p(capture) increased for insects with greater dispersal ability but was generally unresponsive to size because most captures occurred in central areas. For low dispersing insects, the likelihood of egress was approximately zero with a 3.2-km square grid, whereas an 11.3-km grid was needed to contain highly vagile insects. Trap attractiveness affected p(capture) more strongly than density: lower densities of poorly attractive traps may underperform expectations. Variable density designs demonstrated potential for cost savings but highlighted that resource-intensive outer bands are critical to boundary determination. Results suggesting that many grids are oversized need empirical verification, whereas other principles, such as using circular shapes, are readily adoptable now.

Tolerant Larvae and Sensitive Juveniles: Integrating Metabolomics and Whole-Organism Responses to Define Life-Stage Specific Sensitivity to Ocean Acidification in the American Lobster.

Bentho-pelagic life cycles are the dominant reproductive strategy in marine invertebrates, providing great dispersal ability, access to different resources, and the opportunity to settle in suitable habitats upon the trigger of environmental cues at key developmental moments. However, free-dispersing larvae can be highly sensitive to environmental changes. Among these, the magnitude and the occurrence of elevated carbon dioxide (CO2) concentrations in oceanic habitats is predicted to exacerbate over the next decades, particularly in coastal areas, reaching levels beyond those historically experienced by most marine organisms. Here, we aimed to determine the sensitivity to elevated pCO2 of successive life stages of a marine invertebrate species with a bentho-pelagic life cycle, exposed continuously during its early ontogeny, whilst providing in-depth insights on their metabolic responses. We selected, as an ideal study species, the American lobster Homarus americanus, and investigated life history traits, whole-organism physiology, and metabolomic fingerprints from larval stage I to juvenile stage V exposed to different pCO2 levels. Current and future ocean acidification scenarios were tested, as well as extreme high pCO2/low pH conditions that are predicted to occur in coastal benthic habitats and with leakages from underwater carbon capture storage (CCS) sites. Larvae demonstrated greater tolerance to elevated pCO2, showing no significant changes in survival, developmental time, morphology, and mineralisation, although they underwent intense metabolomic reprogramming. Conversely, juveniles showed the inverse pattern, with a reduction in survival and an increase in development time at the highest pCO2 levels tested, with no indication of metabolomic reprogramming. Metabolomic sensitivity to elevated pCO2 increased until metamorphosis (between larval and juvenile stages) and decreased afterward, suggesting this transition as a metabolic keystone for marine invertebrates with complex life cycles.

Change in avian functional fingerprints of a Neotropical montane forest over 100 years as an indicator of ecosystem integrity.

Ecologically relevant traits of organisms in an assemblage determine an ecosystem's functional fingerprint (i.e., the shape, size, and position of multidimensional trait space). Quantifying changes in functional fingerprints can therefore provide information about the effects of diversity loss or gain through time on ecosystem condition and is a promising approach to monitoring ecological integrity. This, however, is seldom possible owing to limitations in historical surveys and a lack of data on organismal traits, particularly in diverse tropical regions. Using data from detailed bird surveys from 4 periods across more than a century, and morphological and ecological traits of 233 species, we quantified changes in the avian functional fingerprint of a tropical montane forest in the Andes of Colombia. We found that 78% of the variation in functional space, regardless of period, was described by 3 major axes summarizing body size, dispersal ability (indexed by wing shape), and habitat breadth. Changes in species composition significantly altered the functional fingerprint of the assemblage and functional richness and dispersion decreased 35-60%. Owing to species extirpations and to novel additions to the assemblage, functional space decreased over time, but at least 11% of its volume in the 2010s extended to areas of functional space that were unoccupied in the 1910s. The assemblage now includes fewer large-sized species, more species with greater dispersal ability, and fewer habitat specialists. Extirpated species had high functional uniqueness and distinctiveness, resulting in large reductions in functional richness and dispersion after their loss, which implies important consequences for ecosystem integrity. Conservation efforts aimed at maintaining ecosystem function must move beyond seeking to sustain species numbers to designing complementary strategies for the maintenance of ecological function by identifying and conserving species with traits conferring high vulnerability such as large body size, poor dispersal ability, and greater habitat specialization. Article impact statement: Changes in functional fingerprints provide a means to quantify the integrity of ecological assemblages affected by diversity loss or gain.

Sea sandwort from Surtsey: chromosomal evidence of active evolution via wide-hybridization

Sea sandwort (Honckenya peploides) was among the first species of vascular plants colonizing Surtsey. It is a member of the carnation family, Caryophyllaceae, a coastal plant with circumpolar distribution. The species is dioecious comprising separate female and hermaphrodite (male) plants. Our previous study of this plant revealed high molecular polymorphism, indicating rapid expansion and multiple origins, but low genetic differentiation, suggesting gene flow on Surtsey. The maintenance and/or expansion of populations with high gene diversity on the island are most likely fostered by several factors, one of them being the polyploid nature of the study species providing fixed heterozygosity. We therefore investigated chromosome number diversity of H. peploides from Surtsey, in comparison with accessions from Heimaey and other locations within and outside Iceland. Seeds were germinated with and without cold stratification. Chromosomes were isolated from root tips using the cellulase-pectinase enzymatic squash method. DAPIstained chromosomes were counted from microscopic images that were taken at 1000x magnification. The results show that the most common 2n somatic chromosome number of this species is 68 (2n=4x=68), but a tetraploid cytotype with 66 chromosomes also exists. The karyotype analysis shows that the species is an autotetraploid, most likely originating via chromosome doubling (whole genome duplication) in a diploid ancestor. Numerous other 2n numbers were discovered, from the diploid number 2n=2x=34 in Heimaey to several different numbers between 40 and 64. The triploid hybrid numbers 2n=3x=51 (50-52) were discovered from both Surtsey and Heimaey, as well as from other regions. Triploid hybrids serve as a bridge promoting gene flow within populations, promoting heterozygosity in the tetraploid species. All other numbers are aneuploids, most likely deriving from back-crossing of triploid hybrids and the euploid parents. The presence of aneuploids across the species distribution range is due to its ability to propagate asexually by clonal expansion. The presence of the lower ploidy levels within species, together with the extensive aneuploidy, may be an evolutionary characteristic of a pioneering plant, with great dispersal ability and genetic diversity, such as sea sandwort.

Population Genomics Reveals Shallow Genetic Structure in a Connected and Ecologically Important Fish From the Northwestern Pacific Ocean

Genetic variation at the genomic level is invaluable to identify fish stock structure in fisheries management. It has been widely accepted that populations of marine fishes are highly connected owing to fewer barriers to gene flow and increased connectivity resulting from greater dispersal abilities. Since population genomic approaches have increased the accessibility and resolution of population genetic data, it further facilitates to study and detect previously unidentified structures as well as signatures for natural selection in wild populations. In the present study, restriction-site associated DNA (RAD) sequencing was applied to the samples of genome-wide single nucleotide polymorphisms (SNPs) of Engraulis japonicus, a small pelagic fish of ecological and economic importance in the northwestern Pacific. To assess population genetic structure as well as detection for local adaptation of E. japonicus, a total of 389 individuals from six regional populations of the northwestern Pacific were collected and a set of 12,627 SNPs was developed. Marginal significant genetic structure (average FST value was approximately equal to 0.002) was detected between regional populations of “the Bohai Sea population (BHS)” and the “the Japan Sea population (JPS)” as well as between “the North Yellow Sea population (NYS)” and the “the Japan Sea population (JPS)”. Moreover, no sign of local adaptation was detected, which might be the product of high gene flow among regional populations. Overall, our results improve the understanding of fine-scale population genetic structure in E. japonicus and potentially identify management unit in this species area.

First occurrence of the Cambrian arthropodSidneyiaWalcott, 1911 outside of Laurentia

AbstractThe arthropodSidneyiaWalcott, 1911 is a remarkable animal of the Burgess Shale biota (Cambrian Miaolingian, Wuliuan; British Columbia, Canada), which has not been confidently reported from other Cambrian Konservat-Lagerstätten. Here we report the discovery ofSidneyiacf.inexpectansfrom the Wuliuan Mantou Formation of North China, which substantially expands the known palaeogeographical distribution of this genus. Our discovery suggests thatSidneyiahad much greater dispersal ability than hitherto thought. It also confirms the presence of exceptionally preserved fossils in the Wuliuan Mantou Formation, one of the rare Burgess Shale-type deposits of North China.

Large-scale distribution of bacterial communities in the Qaidam Basin of the Qinghai-Tibet Plateau.

Many studies have investigated patterns of soil microbial communities over large spatial scales. However, these studies mainly focused on a few sites. Here, we studied the near‐surface (0–30 cm) soil microbial communities of 35 soil samples collected from most of the areas of the Qaidam Basin, which is the largest basin on the Qinghai–Tibet Plateau. A total of 32 phyla and 838 genera were detected from all the samples, in which Actinobacteria, Proteobacteria, Bacteroidetes, and Acidobacteria were the most dominant and cosmopolitan phyla. The most abundant phyla (relative abundance > 5%) detected in all 35 soil samples were also the most dominant, which could be explained by their great dispersal ability. The microbial community structures correlated strongly with variations in pH and Mg2+ and were distinct between the high Mg2+ content (>20 g/kg) samples and other samples (Acidobacteria, Actinobacteria, and Chloroflexi were significantly less abundant in the high Mg2+ content group, but the abundance of Firmicutes was significantly greater). Finally, the microbial spatial pattern was influenced by both the local environment and spatial distance, but environmental factors were the primary drivers of microbial spatial patterns in the Qaidam Basin.

Landscape permeability and individual variation in a dispersal-linked gene jointly determine genetic structure in the Glanville fritillary butterfly.

There is now clear evidence that species across a broad range of taxa harbor extensive heritable variation in dispersal. While studies suggest that this variation can facilitate demographic outcomes such as range expansion and invasions, few have considered the consequences of intraspecific variation in dispersal for the maintenance and distribution of genetic variation across fragmented landscapes. Here, we examine how landscape characteristics and individual variation in dispersal combine to predict genetic structure using genomic and spatial data from the Glanville fritillary butterfly. We used linear and latent factor mixed models to identify the landscape features that best predict spatial sorting of alleles in the dispersal‐related gene phosphoglucose isomerase (Pgi). We next used structural equation modeling to test if variation in Pgi mediated gene flow as measured by Fst at putatively neutral loci. In a year when the population was recovering following a large decline, individuals with a genotype associated with greater dispersal ability were found at significantly higher frequencies in populations isolated by water and forest, and these populations showed lower levels of genetic differentiation at neutral loci. These relationships disappeared in the next year when metapopulation density was high, suggesting that the effects of individual variation are context dependent. Together our results highlight that (1) more complex aspects of landscape structure beyond just the configuration of habitat can be important for maintaining spatial variation in dispersal traits and (2) that individual variation in dispersal plays a key role in maintaining genetic variation across fragmented landscapes.

Only true pelagics mix: comparative phylogeography of deepwater bathybatine cichlids from Lake Tanganyika

In the absence of dispersal barriers, species with great dispersal ability are expected to show little, if at all, phylogeographic structure. The East African Great Lakes and their diverse fish faunas provide opportunities to test this hypothesis in pelagic fishes, which are presumed to be highly mobile and unrestricted in their movement by physical barriers. Here, we address the link between panmixis and pelagic habitat use by comparing the phylogeographic structure among four deepwater cichlid species of the tribe Bathybatini from Lake Tanganyika. We show that the mitochondrial genealogies (based on the most variable part or the control region) of the four species are very shallow (0.8–4% intraspecific divergence across entire distribution ranges) and that all species experienced recent population growth. A lack of phylogeographic structure in the two eupelagic species, Bathybates fasciatus and B. leo, was consistent with expectations and with findings in other pelagic cichlid species. Contrary to expectations, a clear phylogeographic structure was detected in the two benthopelagic species, B. graueri and Hemibates stenosoma. Differences in genetic diversity between eupelagic and benthopelagic species may be due to differences in their dispersal propensity, mediated by their respective predatory niches, rather than precipitated by external barriers to dispersal.

Conservation concern’ bryophytes find refuge on cave entrances in the Azores

Bryophytes, including mosses, liverworts and hornworts, are terrestrial plants, with a particular life cycle where the gametophyte is dominant over the sporophyte; many species are pokilohydric, meaning that they achieve a quick equilibrium between the cell water content and that of the environment, suspending their life, but not dying, in the absence of water. Due to their light spores, these plants have a great dispersal ability and may be found from the poles to the equator. In the Azores, there are almost 500 species (Gabriel et al. 2010), colonizing a large number of habitats and substrata, but forming particularly luxuriant communities inside native forests. Nevertheless, these forests are presently restricted to medium-high elevations (above 500 m) and below this altitude, adequate habitats for many bryophyte species are scarce (Henriques et al. 2016). Cave entrances, at different elevations, serve as surrogate habitats for bryophyte species, since they present an adequate relative humidity, fewer competitor species and are usually not disturbed by chemical products such as herbicides or pesticides. The aims of this work are twofold: present the results of the first IUCN red-list assessment of the conservation status of Azorean conservation concern bryophytes; and present an overview of the major threats involving the conservation of those species. present the results of the first IUCN red-list assessment of the conservation status of Azorean conservation concern bryophytes; and present an overview of the major threats involving the conservation of those species. The assessments of extinction risk were based on the most updated categories and criteria. Seven liverworts (Calypogeia azorica, Cheilolejeunea cedercreutzii, Fuscocephaloziopsis crassifolia, Leptoscyphus porphyrius subsp. azoricus, Lophocolea fragrans Plagiochila longispina and Radula holtii,) and seven mosses (Andoa berthelotiana, Echinodium renauldii, Heterocladium flaccidum, Hookeria lucens, Microcampylopus laevigatus, Rhynchostegiella trichophylla and Thamnobryum rudolphianum) benefit from populations at cave entrances, mostly the Azorean and Macaronesian endemic species. The three most common threats harming “cave” bryophytes include: climate change & severe weather, habitat change and degradation and invasive plant species of native forest. These threats are also documented in the literature (e.g. Patiño et al. 2016; Ferreira et al. 2016; Triantis et al. 2010 and Silva et al. 2008). Cave habitats are thus an important part of bryophyte conservation in the Azores, and should be both legally protected and monitored to the mutual benefit of species and habitat conservation.

Have your cake and eat it too: greater dispersal ability and faster germination towards range edges of an invasive plant species in eastern Australia

The process of range expansion often selects for traits that maximize invasion success at range edges. For example, during range expansion, individuals with greater dispersal and colonization ability will be selected for towards range edges. For wind dispersed plants, however, there exists a fundamental trade-off between dispersal and colonization ability (germination success and growth) that is mediated by seed size; smaller seeds often have greater dispersal ability but poorer colonization ability. We investigated the nature of the dispersal/colonization trade-off by comparing dispersal ability (wing loading ratio: seed mass/wing area), germination success and growth related traits across multiple populations of a coastal exotic invasive plant species (Gladiolus gueinzii Kunze) along its entire introduced distribution in eastern Australia. We found that G. gueinzii had significantly greater dispersal ability towards its range edges which was mediated by a decrease in seed mass. However, this was not associated with a decrease in probability of germination or growth after 3 months. In fact, seeds from range edge populations had significantly faster germination times. Our results suggest that a shift towards greater dispersal ability does not have an associated negative effect on the colonization ability of G. gueinzii and may be a key factor in promoting further range expansion of this exotic invasive species.

Species' traits as predictors of range shifts under contemporary climate change: A review and meta-analysis.

A growing body of literature seeks to explain variation in range shifts using species' ecological and life-history traits, with expectations that shifts should be greater in species with greater dispersal ability, reproductive potential, and ecological generalization. Despite strong theoretical support for species' traits as predictors of range shifts, empirical evidence from contemporary range shift studies remains limited in extent and consensus. We conducted the first comprehensive review of species' traits as predictors of range shifts, collecting results from 51 studies across multiple taxa encompassing over 11,000 species' responses for 54 assemblages of taxonomically related species occurring together in space. We used studies of assemblages that directly compared geographic distributions sampled in the 20th century prior to climate change with resurveys of distributions after contemporary climate change and then tested whether species traits accounted for heterogeneity in range shifts. We performed a formal meta-analysis on study-level effects of body size, fecundity, diet breadth, habitat breadth, and historic range limit as predictors of range shifts for a subset of 21 studies of 26 assemblages with sufficient data. Range shifts were consistent with predictions based on habitat breadth and historic range limit. However, body size, fecundity, and diet breadth showed no significant effect on range shifts across studies, and multiple studies reported significant relationships that contradicted predictions. Current understanding of species' traits as predictors of range shifts is limited, and standardized study is needed for traits to be valid indicators of vulnerability in assessments of climate change impacts.

Genetic diversity ofNephtys hombergii(Phyllodocida, Polychaeta) associated with environmental factors in a highly fluctuating ecosystem

Genetic diversity and population distribution are influenced by environmental factors, yet information is scarce on the interrelations that define dispersal of populations. Transitional water ecosystems are hosting habitats with temporally and spatially variable conditions, which make them very useful in understanding the mechanisms affecting population establishment. For the study, seasonal samples were collected from four lagoons in the lagoonal complex of Amvrakikos Gulf (W Greece). The mitochondrial DNA (COI gene) was analysed from polychaetes ofNephtys hombergii, as it is considered an important component of these assemblages and shows great dispersal ability. The results of the genetic analysis showed intraspecific variability in all the lagoons, with genetic structuring tending to follow a seasonal pattern rather than a spatial one. The results of BIOENV analysis indicated correlation of the observed pattern with the water pH levels, the redox potential and the concentration of phosphate in the sediment. The complexity of the network suggested the enhancement of the local population with more recently established haplotypes. The findings of the study support the necessity of designing management strategies by taking into account genetic diversity and population demography approaches in addition to those based on species and habitats.

How do field margins contribute to the functional connectivity of insect-pollinated plants?

Habitat fragmentation generates a loss of functional connectivity detrimental to the persistence of biodiversity. The French agricultural intensification initiated in the 1950s has caused a decline in field margins. As field margins may facilitate species dispersal while providing socio-economic benefits, it is of interest to assess their contribution to the functional connectivity of insect-pollinated plants in agro-ecosystems. This will help develop appropriate management strategies mitigating fragmentation. We addressed this issue by studying the links between landscape structure and the patterns of abundance and pollen dispersal (using fluorescent dye particles) for two contrasted insect-pollinated plants occurring in field margins (Crepis sancta and Euphorbia serrata). We investigated the influence of field margins quality and of the surrounding matrix on pollen dispersal and compared the relevance of the least-cost algorithm with a straight-line approach to depict pollinators’ movements. The influence of landscape structure on plant abundance is species and scale-specific. Pollen dispersal decreases with distance from the source. For E. serrata, it was preferentially dispersed via field margins, confirming the relevance of the least-cost algorithm, while C. sancta dispersal followed a straight-line. Euphorbia serrata, which grows strictly on field margins with a greater dispersal ability and a more diversified pollinator guild than C. sancta, is less affected by land-use changes. Our study demonstrates the contrasting contributions of field margins to pollen dispersal as they may act as functional corridors favouring pollinators’ movement depending on the species of interest.

Spatial synchrony in stream fish populations: influence of species traits

Spatial synchrony in population dynamics has been identified in most taxonomic groups. Numerous studies have reported varying levels of spatial synchrony among closely‐related species, suggesting that species' characteristics may play a role in determining the level of synchrony. However, few studies have attempted to relate this synchrony to the ecological characteristics and/or life‐history traits of species. Yet, as to some extent the extinction risk may be related to synchrony patterns, identifying a link between species' characteristics and spatial synchrony is crucial, and would help us to define effective conservation planning. Here, we investigated whether species attributes and temperature synchrony (i.e. a proxy of the Moran effect) account for the differences in spatial population synchrony observed in 27 stream fish species in France. After measuring and testing the level of synchrony for each species, we performed a comparative analysis to detect the phylogenetic signal of these levels, and to construct various multi‐predictor models with species traits and temperature synchrony as covariates, while taking phylogenetic relatedness into account. We then performed model averaging on selected models to take model uncertainty into account in our parameter estimates. Fifteen of the 27 species displayed a significant level of synchrony. Synchrony was weak, but highly variable between species, and was not conserved across the phylogeny. We found that some species' characteristics significantly influenced synchrony levels. Indeed, the average model indicated that species associated with greater dispersal abilities, lower thermal tolerance, and opportunistic strategy displayed a higher degree of synchrony. These findings indicate that phylogeny and spatial temperature synchrony do not provide information pertinent for explaining the variations in species' synchrony levels, whereas the dispersal abilities, the life‐history strategies and the upper thermal tolerance limits of species do appear to be quite reliable predictors of synchrony levels.

A panmictic fiddler crab from the coast of Brazil? Impact of divergent ocean currents and larval dispersal potential on genetic and morphological variation in Uca maracoani

Marine species tend to exhibit relatively less population structuring than terrestrial species owing to fewer barriers to gene flow and increased connectivity resulting from greater dispersal abilities. Thus, in many cases, life history plays a more important role in phylogeography of marine taxa than do oceanographic features. Littoral species are of particular phylogeographic interest because they possess life histories that have both marine and terrestrial characteristics. This study evaluates the synergistic impact of divergent ocean currents and a high larval dispersal potential on the phylogeography of the fiddler crab, Uca maracoani, distributed along the coast of Brazil. Patterns of genetic variation were assessed with sequence data for a portion of the mitochondrial COI gene and AFLPs. Geometric morphometric techniques were used to evaluate morphological variation. Results revealed a lack of discernible genetic subdivision. However, geometric morphometrics showed statistically significant morphological differentiation. The absence of a clear phylogeographic pattern appears to be determined primarily by life history characteristics permitting a high level of connectivity. One, or a combination of several factors, may explain the incongruity between genetic and morphologic signatures, including phenotypic plasticity, incomplete lineage sorting, or recent and ongoing genetic divergence.

Allometric Relations of Neotropical Small Rodents (Sigmodontinae) in Anthropogenic Environments

The present study aims at assessing allometric relationships in the Sigmodontinae rodents (Calomys tener, Akodon cf. montensis, Necromys lasiurus, Oligoryzomys flavescens, and Oligoryzomys nigripes), and morphological variation among different habitats in human-dominated environments in Southeastern Brazil. We captured rodents using pitfall traps placed in Eucalyptus plantations, abandoned pastures, and remnants of secondary native vegetation, and took the following measurements: body mass, total length, body length, left hind foot length, and left ear length. Males were usually larger than females, except in N. lasiurus. There was no intraspecific difference in body condition among habitats, suggesting that Eucalyptus may not have a deleterious effect upon its residents. However, A. cf montensis from Eucalyptus plantations had longer feet than those from other vegetation associations, suggesting a possible adaptive response to the lower cover in the plantation environment, and its consequent higher predation risk, or alternatively that only individuals with greater dispersal ability are found in Eucalyptus plantations. Future studies should investigate a possible co-evolutionary predator-prey relationship, including rapid evolution by Sigmodontinae rodents in anthropogenic landscapes.