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Title Date Issued Date Released Description
Data from: Evolution determines how global warming and pesticide exposure will shape predator–prey interactions with vector mosquitoes
06-15-2016 08-15-2016
How evolution may mitigate the effects of global warming and pesticide exposure on predator–prey interactions is directly relevant for vector control. Using a space-for-time substitution approach, we addressed how 4°C warming and exposure to the pesticide endosulfan shape the predation on Culex pipiens mosquitoes by damselfly predators from replicated low- and high-latitude populations. Although warming was only lethal for the mosquitoes, it reduced predation rates on these prey. Possibly, under warming escape speeds of the mosquitoes increased more than the attack efficiency of the predators. Endosulfan imposed mortality and induced behavioral changes (including increased filtering and thrashing and a positional shift away from the bottom) in mosquito larvae. Although the pesticide was only lethal for the mosquitoes, it reduced predation rates by the low-latitude predators. This can be explained by the combination of the evolution of a faster life history and associated higher vulnerabilities to the pesticide (in terms of growth rate and lowered foraging activity) in the low-latitude predators and pesticide-induced survival selection in the mosquitoes. Our results suggest that predation rates on mosquitoes at the high latitude will be reduced under warming unless predators evolve toward the current low-latitude phenotype or low-latitude predators move poleward.
Data from: Flap or soar? How a flight generalist responds to its aerial environment
08-15-2016 08-15-2016
The aerial environment is heterogeneous in space and time and directly influences the costs of animal flight. Volant animals can reduce these costs by using different flight modes, each with their own benefits and constraints. However, the extent to which animals alter their flight modes in response to environmental conditions has rarely been studied in the wild. To provide insight into how a flight generalist can reduce the energetic cost of movement, we studied flight behaviour in relation to the aerial environmental and landscape using hundreds of hours of global positioning system and triaxial acceleration measurements of the lesser black-backed gull (Larus fuscus). Individuals differed largely in the time spent in flight, which increased linearly with the time spent in flight at sea. In general, flapping was used more frequently than more energetically efficient soaring flight. The probability of soaring increased with increasing boundary layer height and time closer to midday, reflecting improved convective conditions supportive of thermal soaring. Other forms of soaring flight were also used, including fine-scale use of orographic lift. We explore the energetic consequences of behavioural adaptations to the aerial environment and underlying landscape and implications for individual energy budgets, foraging ecology and reproductive success.
Data from: Constraints on geographic variation in fiddler crabs (Ocypodidae: Uca) from the western Atlantic
08-08-2016 11-23-2016
A key question in evolutionary biology is how intraspecific variation biases the evolution of a population and its divergence from other populations. Such constraints potentially limit the extent to which populations respond to selection, but may endure long enough to have macroevolutionary consequences. Previous studies have focused on the association between covariation patterns and divergence among isolated populations. Few have focused on geographic variation among semi-connected populations, however, even though this may be indicative of early selective pressures that could lead to long-term divergence and speciation. Here, we test whether covariation in the shape of the carapace of fiddler crabs (genus Uca Leach, 1814) is important for structuring geographic variation. We find that morphological divergence among populations is associated with evolvability in the direction of divergence in only a few species. The shape of the ancestral covariation matrix in these species differs from other species in having notably more variation concentrated along fewer directions (i.e., higher eccentricity). For most species, there is some evidence that covariation has constrained the range of directions into which populations have diverged but not the degree of divergence. These results suggest that even though fiddler crab populations have diverged morphologically in directions predicted by covariation, constraints on the extent to which divergence has occurred may only be manifested in species where variation patterns are eccentric enough to limit populations’ ability to respond effectively in many directions.
Data from: Long live the alien: is high genetic diversity a pivotal aspect of crested porcupine (Hystrix cristata) long-lasting and successful invasion?
05-12-2016 09-29-2016
Studying the evolutionary dynamics of an alien species surviving and continuing to expand after several generations can provide fundamental information on the relevant features of clearly successful invasions. Here, we tackle this task by investigating the dynamics of the genetic diversity in invasive crested porcupine (Hystrix cristata) populations, introduced to Italy about 1500 years ago, which are still growing in size, distribution range and ecological niche. Using genome-wide RAD markers, we describe the structure of the genetic diversity and the demographic dynamics of the H. cristata invasive populations and compare their genetic diversity with that of native African populations of both H. cristata and its sister species, H. africaeaustralis. First, we demonstrate that genetic diversity is lower in both the invasive Italian and the North Africa source range relative to other native populations from sub-Saharan and South Africa. Second, we find evidence of multiple introduction events in the invasive range followed by very limited gene flow. Through coalescence-based demographic reconstructions, we also show that the bottleneck at introduction was mild and did not affect the introduced genetic diversity. Finally, we reveal that the current spatial expansion at the northern boundary of the range is following a leading-edge model characterized by a general reduction of genetic diversity towards the edge of the expanding range. We conclude that the level of genome-wide diversity of H. cristata invasive populations is less important in explaining its successful invasion than species-specific life-history traits or the phylogeographic history in the native source range.
Data from: Investigating the impacts of field-realistic exposure to a neonicotinoid pesticide on bumblebee foraging, homing ability and colony growth
05-10-2016 05-16-2017
The ability to forage and return home is essential to the success of bees as both foragers and pollinators. Pesticide exposure may cause behavioural changes that interfere with these processes, with consequences for colony persistence and delivery of pollination services. We investigated the impact of chronic exposure (5–43 days) to field-realistic levels of a neonicotinoid insecticide (2·4 ppb thiamethoxam) on foraging ability, homing success and colony size using radio frequency identification (RFID) technology in free-flying bumblebee colonies. Individual foragers from pesticide-exposed colonies carried out longer foraging bouts than untreated controls (68 vs. 55 min). Pesticide-exposed bees also brought back pollen less frequently than controls indicating reduced foraging performance. A higher proportion of bees from pesticide-exposed colonies returned when released 1 km from their nests; this is potentially related to increased orientation experience during longer foraging bouts. We measured no impact of pesticide exposure on homing ability for bees released from 2 km, or when data were analysed overall. Despite a trend for control colonies to produce more new workers earlier, we found no overall impacts of pesticide exposure on whole colony size. Synthesis and applications. This study shows that field-realistic neonicotinoid exposure can have impacts on both foraging ability and homing success of bumblebees, with implications for the success of bumblebee colonies in agricultural landscapes and their ability to deliver crucial pollination services. Pesticide risk assessments should include bee species other than honeybees and assess a range of behaviours to elucidate the impact of sublethal effects. This has relevance for reviews of neonicotinoid risk assessment and usage policy world-wide.
Data from: Coupled range dynamics of brood parasites and their hosts responding to climate and vegetation changes
05-07-2016 08-16-2016
As populations shift their ranges in response to global change, local species assemblages can change, setting the stage for new ecological interactions, community equilibria, and evolutionary responses. Here we focus on the range dynamics of four avian brood parasite species and their hosts in southern Africa, in a context of bush encroachment (increase in woody vegetation density in places previously occupied by savanna-grassland mosaics) favouring some species at the expense of others. We first tested whether hosts and parasites constrained each other's ability to expand or maintain their ranges. Second, we investigated whether range shifts represented an opportunity for new host-parasite and parasite-parasite interactions. We used multi-species dynamic occupancy models with interactions, fitted to citizen-science data, to estimate the contribution of interspecific interactions to range shifts and to quantify the change in species co-occurrence probability over a 25-year period. Parasites were able to track their hosts’ range shifts. We detected no deleterious effect of the parasites’ presence on either the local population viability of host species or the hosts’ ability to colonize newly suitable areas. In the recently diversified indigobird radiation (Vidua spp.), following bush encroachment, the new assemblages presented more potential opportunities for speciation via host switch, but also more potential for hybridization between extant lineages, also via host switch. Multi-species dynamic occupancy models with interactions brought new insights into the feedbacks between range shifts, biotic interactions, and local demography: brood parasitism had little detected impact on extinction or colonization processes, but inversely the latter processes affected biotic interactions via the modification of co-occurrence patterns.
Data from: Taxonomic and functional diversity in Mediterranean pastures: Insights on the biodiversity-productivity trade-off
05-03-2016 09-23-2016
Agricultural intensification is one of the main causes of biodiversity loss world-wide. The inclusion of semi-natural features in agricultural landscapes is suggested as a means of enhancing farm biodiversity, but this practice may have potential negative effects on yield production. Moreover, little evidence exists for effects of semi-natural features on other components of biodiversity, such as functional diversity. Yet this could provide a more comprehensive understanding of biodiversity–productivity trade-offs. Here, we report the effects of semi-natural woody vegetation on taxonomic and functional diversity, and biomass production of herbaceous species at the field and farm scales by sampling 50 fields, ranging from 0 to 90% woody vegetation cover, on nine similarly managed farms in central-western Spain. We found significant differences in herbaceous species richness among farms. Both taxonomic and functional β-diversity exhibited significant negative relationships with herbage production, highlighting the trade-off between biodiversity and productivity in these agroecosystems. Woody vegetation cover had a significant negative relationship with biomass production and a unimodal relationship with species richness at the field scale. At high values of woody vegetation cover, species richness and functional diversity indices were decoupled, suggesting that at this extreme of the woody vegetation gradient, only herbaceous species with contrasting trait values were present. Our results showed both convergent and divergent patterns of trait values, suggesting that different assembly processes are acting concurrently along the gradient of woody vegetation. Synthesis and applications. Our result indicates that management of woody vegetation may indeed increase both taxonomic and functional diversity, but this may come at the expense of key ecosystem services or other management goals, namely herbage production. Optimization of the trade-off between herbage diversity and productivity can be reached with a woody vegetation cover of c. 30% at the field scale.
Data from: Genetic variability, local selection and demographic history: genomic evidence of evolving towards allopatric speciation in Asian seabass
06-04-2016 10-31-2016
Genomewide analysis of genetic divergence is critically important in understanding the genetic processes of allopatric speciation. We sequenced RAD tags of 131 Asian seabass individuals of six populations from South-East Asia and Australia/Papua New Guinea. Using 32 433 SNPs, we examined the genetic diversity and patterns of population differentiation across all the populations. We found significant evidence of genetic heterogeneity between South-East Asian and Australian/Papua New Guinean populations. The Australian/Papua New Guinean populations showed a rather lower level of genetic diversity. FST and principal components analysis revealed striking divergence between South-East Asian and Australian/Papua New Guinean populations. Interestingly, no evidence of contemporary gene flow was observed. The demographic history was further tested based on the folded joint site frequency spectrum. The scenario of ancient migration with historical population size changes was suggested to be the best fit model to explain the genetic divergence of Asian seabass between South-East Asia and Australia/Papua New Guinea. This scenario also revealed that Australian/Papua New Guinean populations were founded by ancestors from South-East Asia during mid-Pleistocene and were completely isolated from the ancestral population after the last glacial retreat. We also detected footprints of local selection, which might be related to differential ecological adaptation. The ancient gene flow was examined and deemed likely insufficient to counteract the genetic differentiation caused by genetic drift. The observed genomic pattern of divergence conflicted with the ‘genomic islands’ scenario. Altogether, Asian seabass have likely been evolving towards allopatric speciation since the split from the ancestral population during mid-Pleistocene.
Data from: Shared phylogeographical breaks in a Caribbean coral reef sponge and its invertebrate commensals
06-15-2016 11-18-2016
Aim: To test whether phylogeographical barriers in the brooding sponge Callyspongia vaginalis match breaks previously identified in the Caribbean. We also compared patterns of subdivision in the sponge to those of three of its commensals, the broadcast spawning brittle star Ophiothrix suensonii and the brooding amphipods Leucothoe ashleyae and L. kensleyi, and tested whether any shared breaks arose simultaneously. Location: Florida, Bahamas and the Caribbean. Methods: Subdivision of C. vaginalis populations was inferred from one mitochondrial (COI) and six nuclear loci using clustering analyses. We identified phylogeographical breaks in the sponge and its invertebrate commensals by determining geographical patterns of genetic variation and tested simultaneous population divergence across barriers shared among taxa using hierarchical approximate Bayesian computation. Results: Sponge populations were partitioned into western and eastern groups across the Caribbean, with hierarchical subdivision within regions. The sponge and its commensals shared barriers across their ranges despite differences in dispersal strategy: C. vaginalis, L. ashleyae and O. suensonii populations in Central America were isolated from the remainder of the Caribbean, and all four taxa shared a break between Florida and the Bahamas, although simultaneous population divergence could not be inferred with statistical certainty. Our results also suggest cryptic speciation within C. vaginalis. Main conclusions: Phylogeographical patterns in C. vaginalis largely matched barriers previously identified at the Florida Straits, Mona Passage and Bay of Honduras in other Caribbean taxa. Oceanographic features such as deep water between locations, strong currents, and eddies are likely mechanisms responsible for these breaks.
Data from: Direct and indirect effects of native range expansion on soil microbial community structure and function
05-30-2016 09-28-2016
Analogous to the spread of non-native species, shifts in native species’ ranges resulting from climate and land use change are also creating new combinations of species in many ecosystems. These native range shifts may be facilitated by similar mechanisms that provide advantages for non-native species and may also have comparable impacts on the ecosystems they invade. Soil biota, in particular bacteria and fungi, are important regulators of plant community composition and below-ground ecosystem function. Compared to non-native plant invasions, there have been relatively few studies examining how soil biota influence – or are influenced by – native species range shifts. Here, we examined how a native range-expanding sagebrush species (Artemisia rothrockii) affects below-ground abiotic conditions and microbial community structure and function using next-generation sequencing coupled with other biotic and abiotic soil analyses. We utilized a range-expansion gradient, together with a shrub removal experiment and structural equation models, to determine the direct and indirect drivers of these interconnected processes. Sagebrush colonization increased bacterial and archaeal richness and diversity and altered community composition across the expansion gradient. Soil organic C and N and soil moisture increased with sagebrush presence; however, results varied across the expansion gradient. We found no relationship between sagebrush and soil pH; however, pH strongly influenced microbial richness and diversity. Microbial (substrate-induced) respiration was influenced by soil organic N, as well as microbial diversity and functional group relative abundances, highlighting direct and indirect effects of sagebrush on microbial community structure and function. Microbial community composition of soils after 4 years of sagebrush removal was more similar to communities in shrub interspaces than underneath shrubs, suggesting microbial community resilience. Synthesis. Our results suggest that native range expansions can have important impacts on soil biological communities, soil chemistry and hydrology which can further impact below-ground ecosystem processes such as nutrient cycling and litter decomposition. The combination of high-throughput sequencing and structural equation modelling used here offers an exciting yet underutilized approach to understanding how both native and non-native species’ range expansions may affect the structure and function of soil ecosystems.
Data from: A revision of the Leptogium saturninum group in North America
09-23-2016 10-11-2016
A revision of the North American members of the Leptogium saturninum group (i.e. species with long lower-surface hairs, isidia, and usually smooth upper surface) is presented based on molecular phylogenetic analyses of mtSSU and nrITS sequence data, together with an extensive morphological study. Three species supported by both molecular and morphological characteristics are recognized: L. acadiense sp. nov. (distinguished by granular saturninum-type isidia, medulla composed of irregularly arranged or perpendicular hyphae), L. cookii sp. nov. (distinguished by cylindrical saturninum-type isidia) and L. hirsutum (distinguished by hirsutum-type isidia and medulla composed of loosely intertwined hyphae). One species supported by morphological characteristics, but for which no molecular data could be generated, is also recognized: L. compactum sp. nov. (distinguished by hirsutum-type isidia and medulla composed of tightly packed hyphae). Finally, L. saturninum (distinguished by granular saturninum-type isidia and medulla composed of perpendicular and parallel hyphae) is supported by morphological characteristics but molecular data from geographically diverse populations, including those near the type locality, indicate that the morphologically defined species is paraphyletic. Leptogium burnetiae is excluded from North American based on morphological study of the type. The species are described and illustrated in detail, and are distinguished morphologically by their isidium development, morphology of mature isidia, and pattern of hyphae in the medulla in transverse sections near lobe margins. A key to the members of the L. saturninum group and related species is also presented.
Data from: Biparental care is predominant and beneficial to parents in the burying beetle Nicrophorus orbicollis (Coleoptera: Silphidae)
05-26-2016 12-14-2016
Parenting strategies can be flexible within a species and may have varying fitness effects. Understanding this flexibility and its fitness consequences is important for understanding why parenting strategies evolve. In the present study, we investigate the fitness consequences of flexible parenting in the burying beetle Nicrophorus orbicollis, a species known for its advanced provisioning behaviour of regurgitated vertebrate carrion to offspring by both sexes. We show that, even when a parent is freely allowed to abandon the carcass at any point in time, biparental post-hatching care is the most common pattern of care adopted in N. orbicollis. Furthermore, two parents together raised more offspring than single parents of either sex, showing that the presence of the male can directly influence parental fitness even in the absence of competitors. This contrasts with studies in other species of burying beetle, where biparental families do not differ in offspring number. This may explain why biparental care is more common in N. orbicollis than in other burying beetles. We suggest how the fitness benefits of two parents may play a role in the evolution and maintenance of flexible biparental care in N. orbicollis.
Data from: Communication value of mistakes in dark-eyed junco song
07-08-2016 08-15-2016
Sexual signals contain information on individual quality or motivation, and most explanations for their reliability are based on signal costs. A recent suggestion is that signaling mistakes, defined as deviations from typical signal design, provide cues on individual quality, contributing to reliable communication even when signal design is not costly. We describe several atypical song traits in dark-eyed juncos (Junco hyemalis) that may be mistakes during song production or development and occur in up to 6% of songs. These putative mistakes were more frequent in an urban versus a wildland population, and individuals differed in their frequency of mistakes. Some atypical signals were more frequent in younger males or were negatively related to paternity success, supporting the hypothesis that fewer mistakes indicate individual quality. We also discuss unexpected results, such as some atypical signals being more frequent in more ornamented males and in songs with lower performance demands. Song consistency (similarity across syllable renditions) was positively related to male age and paternity success; nonetheless, relations with paternity were stronger when looking at the most deviant syllable renditions, suggesting that the perceptual salience of large mistakes may mediate receiver responses to song consistency. Results indicate that signaling mistakes reveal relevant information to play a role in communication.
Data from: Abundance inequality in freshwater communities has an ecological origin
03-03-2016 05-16-2017
The hollow-shaped species abundance distribution (SAD) and its allied rank abundance distribution (RAD)—showing that abundance is unevenly distributed among species—are some of the most studied patterns in ecology. To explain the nature of abundance inequality, I developed a novel framework identifying environmental favorability, which controls the balance between reproduction and immigration, as the ultimate source and species stress tolerance as a proximate factor. Thus, under harsh conditions, only a few tolerant species can reproduce, while some sensitive species can be present in low numbers due to chance immigration. This would lead to high abundance inequality between the two groups of species. Under benign conditions, both groups can reproduce and give rise to higher abundance equality. To test these ideas, I examined the variability in the parameters of a Poisson lognormal fit of the SAD and a square root fit of the RAD in diatom and fish communities across US streams. Indeed, as environmental favorability increased, more sensitive forms were able to establish large populations, diminishing the abundance disparity between locally common and rare species. Finally, it was demonstrated that in diatoms, the RAD belonged to the same family of relationships as those of population density with body size and regional distribution.
Data from: Assessment of markers of antimalarial drug resistance in Plasmodium falciparum isolates from pregnant women in Lagos, Nigeria
01-25-2016 02-25-2016
Background: The use of antimalarial drugs for prevention and treatment is a major strategy in the prevention of malaria in pregnancy. Although sulphadoxine-pyrimethamine (SP) is currently recommended for intermittent preventive treatment of malaria during pregnancy in Nigeria, previously used drugs for prophylaxis such as chloroquine (CQ) and pyrimethamine are accessible as they are purchased over the counter. This study describes the markers of absence or presence of resistance to quinoline (Pfcrt and Pfmdr 1) and type 1 antifolate antimalarial medicines (Pfdhfr). Methods: Plasmodium falciparum-positive dried blood spots from pregnant women attending antenatal clinics for the first time during current pregnancy were investigated for the presence of mutations at codons 72–76 of Plasmodium falciparum chloroquine resistance transporter (Pfcrt) gene by real time polymerase chain reaction (PCR) using haplotype-specific probes. PCR followed by sequence analysis was used to identify mutations at codons 86, 184, 1034, 1042 and 1246 of P. falciparum multi-drug resistance-1 (Pfmdr1) gene; and codons 16, 50, 51, 59, 108, 140 and 164 of Pfdhfr gene. Results: Two haplotypes of Pfcrt (n = 54) were observed: CVMNK 13(24.2%) and CVIET 41 (75.9%) of the samples. The SVMNT haplotype was absent in this population. The Pfmdr1 (n = 28) haplotypes were NYSND 15(53.6%), YYSND 5(17.9%), NFSND 6(21.4%) and YFSND 2(7.1%). The Pfdhfr (n = 15) were ACNCSVI 4(26.7%), and ACICNSVI 1(6.7%) and ACIRNVI 10 (66.7%). The rate of occurrence of Pfcrt 76T, Pfdhfr108N, Pfmdr186Yand184F were 75.9%, 73.3%, 25% and 28.1% respectively. The Pfmdr1 86Y was associated with low parasitaemia (median = 71 parasites/μl, P = 0.024) while Pfcrt 76T was associated with young maternal age (mean 24.1 ± 4.5 years; P = 0.006). The median parasitaemia were similar (P>0.05) in wild and mutant strains of Pfcrt 76, Pfmdr1 184 and Pfdhfr 108. There was no association between gravidity or gestational age of the women and presence of mutations in the Pfcrt, Pfmdr1 or Pfdhfr genes (P>0.05). Conclusion: Markers of resistance to chloroquine and pyrimethamine were high, whereas cycloguanil-resistance marker was not present in the studied population. The low level of mutations in the Pfmdr1gene indicates likely efficacy of amodiaquine against malaria in pregnancy.
Data from: A phylogenetic analysis of egg size, clutch size, spawning mode, adult body size, and latitude in reef fishes
12-10-2015 05-13-2016
Theoretical treatments of egg size in fishes suggest that constraints on reproductive output should create trade-offs between the size and number of eggs produced per spawn. For marine reef fishes, the observation of distinct reproductive care strategies (demersal guarding, egg scattering, and pelagic spawning) has additionally prompted speculation that these strategies reflect alternative fitness optima with selection on egg size differing by reproductive mode and perhaps latitude. Here, we aggregate data from 278 reef fish species and test whether clutch size, reproductive care, adult body size, and latitudinal bands (i.e., tropical, subtropical, and temperate) predict egg size, using a statistically unified framework that accounts for phylogenetic correlations among traits. We find no inverse relationship between species egg size and clutch size, but rather that egg size differs by reproductive mode (mean volume for demersal eggs = 1.22 mm3, scattered eggs = 0.18 mm3, pelagic eggs = 0.52 mm3) and that clutch size is strongly correlated with adult body size. Larger eggs were found in temperate species compared with tropical species in both demersal guarders and pelagic spawners, but this difference was not strong when accounting for phylogenetic correlations, suggesting that differences in species composition underlies regional differences in egg size. In summary, demersal guarders are generally small fishes with small clutch sizes that produce large eggs. Pelagic spawners and egg scatterers are variable in adult and clutch size. Although pelagic spawned eggs are variable in size, those of scatterers are consistently small.
Data from: European wildcat populations are subdivided into five main biogeographic groups: consequences of Pleistocene climate changes or recent anthropogenic fragmentation?
12-07-2015 01-22-2016
Extant populations of the European wildcat are fragmented across the continent, the likely consequence of recent extirpations due to habitat loss and over-hunting. However, their underlying phylogeographic history has never been reconstructed. For testing the hypothesis that the European wildcat survived the Ice Age fragmented in Mediterranean refuges, we assayed the genetic variation at 31 microsatellites in 668 presumptive European wildcats sampled in 15 European countries. Moreover, to evaluate the extent of subspecies/population divergence and identify eventual wild × domestic cat hybrids, we genotyped 26 African wildcats from Sardinia and North Africa and 294 random-bred domestic cats. Results of multivariate analyses and Bayesian clustering confirmed that the European wild and the domestic cats (plus the African wildcats) belong to two well-differentiated clusters (average ФST = 0.159, rst = 0.392, P > 0.001; Analysis of molecular variance [AMOVA]). We identified from c. 5% to 10% cryptic hybrids in southern and central European populations. In contrast, wild-living cats in Hungary and Scotland showed deep signatures of genetic admixture and introgression with domestic cats. The European wildcats are subdivided into five main genetic clusters (average ФST = 0.103, rst = 0.143, P > 0.001; AMOVA) corresponding to five biogeographic groups, respectively, distributed in the Iberian Peninsula, central Europe, central Germany, Italian Peninsula and the island of Sicily, and in north-eastern Italy and northern Balkan regions (Dinaric Alps). Approximate Bayesian Computation simulations supported late Pleistocene–early Holocene population splittings (from c. 60 k to 10 k years ago), contemporary to the last Ice Age climatic changes. These results provide evidences for wildcat Mediterranean refuges in southwestern Europe, but the evolution history of eastern wildcat populations remains to be clarified. Historical genetic subdivisions suggest conservation strategies aimed at enhancing gene flow through the restoration of ecological corridors within each biogeographic units. Concomitantly, the risk of hybridization with free-ranging domestic cats along corridor edges should be carefully monitored.
Data from: Warming alters food web-driven changes in the CO2 flux of experimental pond ecosystems
12-02-2015 12-07-2015
Evidence shows the important role biota play in the carbon cycle, and strategic management of plant and animal populations could enhance CO2 uptake in aquatic ecosystems. However, it is currently unknown how management-driven changes to community structure may interact with climate warming and other anthropogenic perturbations to alter CO2 fluxes. Here we showed that under ambient water temperatures, predators (three-spined stickleback) and nutrient enrichment synergistically increased primary producer biomass, resulting in increased CO2 uptake by mesocosms in early dawn. However, a 3°C increase in water temperatures counteracted positive effects of predators and nutrients, leading to reduced primary producer biomass and a switch from CO2 influx to efflux. This confounding effect of temperature demonstrates that climate scenarios must be accounted for when undertaking ecosystem management actions to increase biosequestration.
Data from: When does intraspecific trait variation contribute to functional beta-diversity?
11-27-2015 03-04-2016
1. Intraspecific trait variation (ITV) is hypothesized to play an important role in community assembly and the maintenance of biodiversity. However, fundamental gaps remain in our understanding of how ITV contributes to mechanisms that create spatial variation in the functional-trait composition of communities (functional β-diversity). Importantly, ITV may influence the perceived importance of environmental filtering across spatial scales. 2. We examined how ITV contributes to functional β-diversity and environmental filtering in woody plant communities in a temperate forest in the Ozark ecoregion, Missouri, USA. To test the hypothesis that ITV contributes to changes in the perceived importance of environmental filtering across scales, we compared patterns of functional β-diversity across soil-resource and topographic gradients at three spatial grains and three spatial extents. To quantify the contribution of ITV to functional β-diversity, we compared patterns that included ITV in five traits (leaf area, specific leaf area, leaf water content, leaf toughness, and chlorophyll content) to patterns based on species-mean trait values. 3. Functional β-diversity that included ITV increased with spatial extent and decreased with spatial grain, suggesting stronger environmental filtering within spatially extensive landscapes that contain populations locally adapted to different habitats. In contrast, functional β-diversity based on species-mean trait values increased with spatial extent but did not change with spatial grain, suggesting weaker environmental filtering among larger communities which each contain a variety of habitats and locally adapted populations. 4. Synthesis. Although studies typically infer community assembly mechanisms from species-mean trait values, our study suggests that mean trait values may mask the strength of assembly mechanisms such as environmental filtering, especially in landscape-scale studies that encompass strong environmental gradients and locally adapted populations. Our study highlights the utility of integrating ITV into studies of functional β-diversity to better understand the ecological conditions under which trait variation within and among species contributes most strongly to patterns of biodiversity across spatial scales.
Data from: High-dimensional variance partitioning reveals the modular genetic basis of adaptive divergence in gene expression during reproductive character displacement
06-03-2011 10-05-2015
Although adaptive change is usually associated with complex changes in phenotype, few genetic investigations have been conducted of adaptations that involve sets of high dimensional traits. Microarrays have supplied high-dimensional descriptions of gene expression, and phenotypic change resulting from adaptation often results in large-scale changes in gene expression. We demonstrate how genetic analysis of large-scale changes in gene expression generated during adaptation can be accomplished by determining by high-dimensional variance partitioning within classical genetic experimental designs. A microarray experiment conducted on a panel of recombinant inbred lines (RILs) generated from two populations of Drosophila serrata that have diverged in response to natural selection, revealed genetic divergence in 10.6% of 3762 gene products examined. Over 97% of the genetic divergence in transcript abundance was explained by only 12 genetic modules. The two most important modules, explaining 50% of the genetic variance in transcript abundance, were genetically correlated with the morphological traits that are known to be under selection. The expression of three candidate genes from these two important genetic modules was assessed in an independent experiment using qRT-PCR on 430 individuals from the panel of RILs, and confirmed the genetic association between transcript abundance and morphological traits under selection.