Practical applications of soil microbiota to improve ecosystem restoration: current knowledge and future directions.

Soil microbiota are important components of healthy ecosystems. Greater consideration of soil microbiota in the restoration of biodiverse, functional, and resilient ecosystems is required to address the twin global crises of biodiversity decline and climate change. In this review, we discuss available and emerging practical applications of soil microbiota into (i) restoration planning, (ii) direct interventions for shaping soil biodiversity, and (iii) strategies for monitoring and predicting restoration trajectories. We show how better planning of restoration activities to account for soil microbiota can help improve progress towards restoration targets. We show how planning to embed soil microbiota experiments into restoration projects will permit a more rigorous assessment of the effectiveness of different restoration methods, especially when complemented by statistical modelling approaches that capitalise on existing data sets to improve causal understandings and prioritise research strategies where appropriate. In addition to recovering belowground microbiota, restoration strategies that include soil microbiota can improve the resilience of whole ecosystems. Fundamentally, restoration planning should identify appropriate reference target ecosystem attributes and - from the perspective of soil microbiota - comprehensibly consider potential physical, chemical and biological influences on recovery. We identify that inoculating ecologically appropriate soil microbiota into degraded environments can support a range of restoration interventions (e.g. targeted, broad-spectrum and cultured inoculations) with promising results. Such inoculations however are currently underutilised and knowledge gaps persist surrounding successful establishment in light of community dynamics, including priority effects and community coalescence. We show how the ecological trajectories of restoration sites can be assessed by characterising microbial diversity, composition, and functions in the soil. Ultimately, we highlight practical ways to apply the soil microbiota toolbox across the planning, intervention, and monitoring stages of ecosystem restoration and address persistent open questions at each stage. With continued collaborations between researchers and practitioners to address knowledge gaps, these approaches can improve current restoration practices and ecological outcomes.

Comparative gene co-expression networks show enrichment of brassinosteroid and vitamin B processes in a seagrass under simulated ocean warming and extreme climatic events.

Introduction: Ocean warming combined with extreme climatic events, such as marine heatwaves and flash flooding events, threaten seagrasses globally. How seagrasses cope with these challenges is uncertain, particularly for range-edge populations of species such as Posidonia australis in Shark Bay, Western Australia. Analyzing gene expression while manipulating multiple stressors provides insight into the genetic response and resilience of seagrasses to climate change. We conducted a gene expression study on a polyploid clone of P. australis during an 18-week mesocosm experiment to assess the responses to single and combined future climate change-associated stressors. Methods: Plants were exposed to (1) future ocean warming temperature (baseline +1.5°C) followed by a simulated marine heat wave (baseline +5.5°C), (2) light deprivation simulating observed marine heatwave driven turbidity (95% shade) at baseline temperatures, or (3) both stressors simultaneously. Basal leaf meristems were sampled for gene expression analysis using RNA-seq at four time points during the experiment. Weighted gene co-expression network analysis, GO term enrichment, and KEGG pathway enrichment analyses were used to identify stress responses. Results: Shaded plants showed specific gene enrichment for shade avoidance (programmed cell death) after three weeks of stress, and before any heated tanks showed a specific heat response. Shaded plants were positively correlated with programmed cell death and stress-related processes at the end of the experiment. Once ocean warming temperatures (+1.5°C) were in effect, gene enrichment for heat stress (e.g., ROS scavenging and polyamine metabolism) was present. Vitamin B processes, RNA polymerase II processes. and light-related meristematic phase changes were expressed with the addition of simulated MHW. Heated plants showed meristematic growth signatures as well as trehalose and salicylic acid metabolism. Brassinosteroid-related processes were significantly enriched in all stressor treatments at all time points, except for the isolated heat-stressed plants three weeks after stressor initiation. Discussion: Gene expression responses to the interaction between heat waves and turbidity-induced light reduction support the observed geographical scale mortality in seagrasses observed for P. australis in Shark Bay, suggesting that even this giant polyploid clone will be negatively impacted by more extreme climate change projections.

Millennia of legal content criteria of lies and truths: wisdom or common-sense folly?

Long before experimental psychology, religious writers, orators, and playwrights described examples of lie detection based on the verbal content of statements. Legal scholars collected evidence from individual cases and systematized them as "rules of evidence". Some of these resemble content cues used in contemporary research, while others point to working hypotheses worth exploring. To examine their potential validity, we re-analyzed data from a quasi-experimental study of 95 perjury cases. The outcomes support the fruitfulness of this approach. Travelling back in time searching for testable ideas about content cues to truth and deception may be worthwhile.

Opportunities and challenges for microbiomics in ecosystem restoration.

Microbiomics is the science of characterizing microbial community structure, function, and dynamics. It has great potential to advance our understanding of plant-soil-microbe processes and interaction networks which can be applied to improve ecosystem restoration. However, microbiomics may be perceived as complex and the technology is not accessible to all. The opportunities of microbiomics in restoration ecology are considerable, but so are the practical challenges. Applying microbiomics in restoration must move beyond compositional assessments to incorporate tools to study the complexity of ecosystem recovery. Advances in metaomic tools provide unprecedented possibilities to aid restoration interventions. Moreover, complementary non-omic applications, such as microbial inoculants and biopriming, have the potential to improve restoration objectives by enhancing the establishment and health of vegetation communities.

Historic and contemporary biogeographic perspectives on range-wide spatial genetic structure in a widespread seagrass.

Historical and contemporary processes drive spatial patterns of genetic diversity. These include climate-driven range shifts and gene flow mediated by biogeographical influences on dispersal. Assessments that integrate these drivers are uncommon, but critical for testing biogeographic hypotheses. Here, we characterize intraspecific genetic diversity and spatial structure across the entire distribution of a temperate seagrass to test marine biogeographic concepts for southern Australia. Predictive modeling was used to contrast the current Posidonia australis distribution to its historical distribution during the Last Glacial Maximum (LGM). Spatial genetic structure was estimated for 44 sampled meadows from across the geographical range of the species using nine microsatellite loci. Historical and contemporary distributions were similar, with the exception of the Bass Strait. Genetic clustering was consistent with the three currently recognized biogeographic provinces and largely consistent with the finer-scale IMCRA bioregions. Discrepancies were found within the Flindersian province and southwest IMCRA bioregion, while two regions of admixture coincided with transitional IMCRA bioregions. Clonal diversity was highly variable but positively associated with latitude. Genetic differentiation among meadows was significantly associated with oceanographic distance. Our approach suggests how shared seascape drivers have influenced the capacity of P. australis to effectively track sea level changes associated with natural climate cycles over millennia, and in particular, the recolonization of meadows across the Continental Shelf following the LGM. Genetic structure associated with IMCRA bioregions reflects the presence of stable biogeographic barriers, such as oceanic upwellings. This study highlights the importance of biogeography to infer the role of historical drivers in shaping extant diversity and structure.

Extensive polyploid clonality was a successful strategy for seagrass to expand into a newly submerged environment.

Polyploidy has the potential to allow organisms to outcompete their diploid progenitor(s) and occupy new environments. Shark Bay, Western Australia, is a World Heritage Area dominated by temperate seagrass meadows including Poseidon's ribbon weed, Posidonia australis. This seagrass is at the northern extent of its natural geographic range and experiences extremes in temperature and salinity. Our genomic and cytogenetic assessments of 10 meadows identified geographically restricted, diploid clones (2n = 20) in a single location, and a single widespread, high-heterozygosity, polyploid clone (2n = 40) in all other locations. The polyploid clone spanned at least 180 km, making it the largest known example of a clone in any environment on earth. Whole-genome duplication through polyploidy, combined with clonality, may have provided the mechanism for P. australis to expand into new habitats and adapt to new environments that became increasingly stressful for its diploid progenitor(s). The new polyploid clone probably formed in shallow waters after the inundation of Shark Bay less than 8500 years ago and subsequently expanded via vegetative growth into newly submerged habitats.

Next generation restoration metrics: Using soil eDNA bacterial community data to measure trajectories towards rehabilitation targets.

In post-mining rehabilitation, successful mine closure planning requires specific, measurable, achievable, relevant and time-bound (SMART) completion criteria, such as returning ecological communities to match a target level of similarity to reference sites. Soil microbiota are fundamentally linked to the restoration of degraded ecosystems, helping to underpin ecological functions and plant communities. High-throughput sequencing of soil eDNA to characterise these communities offers promise to help monitor and predict ecological progress towards reference states. Here we demonstrate a novel methodology for monitoring and evaluating ecological restoration using three long-term (>25 year) case study post-mining rehabilitation soil eDNA-based bacterial community datasets. Specifically, we developed rehabilitation trajectory assessments based on similarity to reference data from restoration chronosequence datasets. Recognising that numerous alternative options for microbiota data processing have potential to influence these assessments, we comprehensively examined the influence of standard versus compositional data analyses, different ecological distance measures, sequence grouping approaches, eliminating rare taxa, and the potential for excessive spatial autocorrelation to impact on results. Our approach reduces the complexity of information that often overwhelms ecologically-relevant patterns in microbiota studies, and enables prediction of recovery time, with explicit inclusion of uncertainty in assessments. We offer a step change in the development of quantitative microbiota-based SMART metrics for measuring rehabilitation success. Our approach may also have wider applications where restorative processes facilitate the shift of microbiota towards reference states.

Restored and remnant Banksia woodlands elicit different foraging behavior in avian pollinators.

Pollinators and the pollination services they provide are critical for seed set and self-sustainability of most flowering plants. Despite this, pollinators are rarely assessed in restored plant communities, where their services are largely assumed to re-establish. Bird-pollinator richness, foraging, and interaction behavior were compared between natural and restored Banksia woodland sites in Western Australia to assess their re-establishment in restored sites. These parameters were measured for natural communities of varying size and degree of fragmentation, and restored plant communities of high and low complexity for three years, in the summer and winter flowering of Banksia attenuata and B. menziesii, respectively. Bird visitor communities varied in composition, richness, foraging movement distances, and aggression among sites. Bird richness and abundance were lowest in fragmented remnants. Differences in the composition were associated with the size and degree of fragmentation in natural sites, but this did not differ between seasons. Restored sites and their adjacent natural sites had similar species composition, suggesting proximity supports pollinator re-establishment. Pollinator foraging movements were influenced by the territorial behavior of different species. Using a network analysis approach, we found foraging behavior varied, with more frequent aggressive chases observed in restored sites, resulting in more movements out of the survey areas, than observed in natural sites. Aggressors were larger-bodied Western Wattlebirds (Anthochaera chrysoptera) and New Holland Honeyeaters (Phylidonyris novaehollandiae) that dominated nectar resources, particularly in winter. Restored sites had re-established pollination services, albeit with clear differences, as the degree of variability in the composition and behavior of bird pollinators for Banksias in the natural sites created a broad completion target against which restored sites were assessed. The abundance, diversity, and behavior of pollinator services to remnant and restored Banksia woodland sites were impacted by the size and degree of fragmentation, which in turn influenced bird-pollinator composition, and were further influenced by seasonal changes between summer and winter. Consideration of the spatial and temporal landscape context of restored sites, along with plant community diversity, is needed to ensure the maintenance of the effective movement of pollinators between natural remnant woodlands and restored sites.

Unexpectedly low paternal diversity is associated with infrequent pollinator visitation for a bird-pollinated plant.

The behaviour of pollinators has important consequences for plant mating. Nectar-feeding birds often display behaviour that results in more pollen carryover than insect pollinators, which is predicted to result in frequent outcrossing and high paternal diversity for bird-pollinated plants. We tested this prediction by quantifying mating system parameters and bird visitation in three populations of an understory bird-pollinated herb, Anigozanthos humilis (Haemodoraceae). Microsatellite markers were used to genotype 131 adult plants, and 211 seeds from 23 maternal plants, from three populations. While outcrossing rates were high, estimates of paternal diversity were surprisingly low compared with other bird-pollinated plants. Despite nectar-feeding birds being common at the study sites, visits to A. humilis flowers were infrequent (62 visits over 21,552 recording hours from motion-triggered cameras, or equivalent to one visit per flower every 10 days), and the majority (76%) were by a single species, the western spinebill Acanthorhynchus superciliosus (Meliphagidae). Pollen counts from 30 captured honeyeaters revealed that A. humilis comprised just 0.3% of the total pollen load. For 10 western spinebills, A. humilis pollen comprised only 4.1% of the pollen load, which equated to an average of 3.9 A. humilis pollen grains per bird. Taken together, our findings suggest that low visitation rates and low pollen loads of floral visitors have led to the low paternal diversity observed in this understory bird-pollinated herb. As such, we shed new light on the conditions that can lead to departures from high paternal diversity for plants competing for the pollination services of generalist nectar-feeding birds.

Optimising the conservation of genetic diversity of the last remaining population of a critically endangered shrub.

An understanding of genetic diversity and the population genetic processes that impact future population viability is vital for the management and recovery of declining populations of threatened species. Styphelia longissima (Ericaceae) is a critically endangered shrub, restricted to a single fragmented population near Eneabba, 250 km north of Perth, Western Australia. For this population, we sought to characterize population genetic variation and its spatial structure, and aspects of the mating portfolio, from which strategies that optimize the conservation of this diversity are identified. A comprehensive survey was carried out and 220 adults, and 106 seedlings from 14 maternal plants, were genotyped using 13 microsatellite markers. Levels of genetic variation and its spatial structure were assessed, and mating system parameters were estimated. Paternity was assigned to the offspring of a subsection of plants, which allowed for the calculation of realized pollen dispersal. Allelic richness and levels of expected heterozygosity were higher than predicted for a small isolated population. Spatial autocorrelation analysis identified fine-scale genetic structure at a scale of 20 m, but no genetic structure was found at larger scales. Mean outcrossing rate (t m = 0.66) reflects self-compatibility and a mixed-mating system. Multiple paternity was low, where 61 % of maternal siblings shared the same sire. Realized pollen dispersal was highly restricted, with 95 % of outcrossing events occurring at 7 m or less, and a mean pollen dispersal distance of 3.8 m. Nearest-neighbour matings were common (55 % of all outcross events), and 97 % of mating events were between the three nearest-neighbours. This study has provided critical baseline data on genetic diversity, mating system and pollen dispersal for future monitoring of S. longissima. Broadly applicable conservation strategies such as implementing a genetic monitoring plan, diluting spatial genetic structure in the natural population, genetically optimizing ex situ collections and incorporating genetic knowledge into translocations will help to manage the future erosion of the high genetic variation detected.

Mock jurors' awareness of age-related changes in memory and cognitive capacity.

While age-related changes in memory have been well documented, findings about jurors' perceptions of older witnesses are conflicting. We investigated the effect of victim age (25 vs. 75 years old) and crime severity (victim injured vs. not injured) on mock jurors' decisions in a robbery trial. Jury-eligible participants (120 women; 84 men) read a mock trial summary and delivered their verdicts online. Mock jurors believed the young victim more than the older victim when the crime was severe, while no age differences emerged for the less severe crime. Whereas previous research demonstrated that juror characteristics were generally associated with culpability, we demonstrated that with case-specific information, these general views became less important. In all, mock jurors were aware of age-related decline in memory provided by eyewitnesses only to a limited extent. Accordingly, in trials involving older witnesses, jurors will benefit from educative information about age-related memory changes.

Conservation of old individual trees and small populations is integral to maintain species' genetic diversity of a historically fragmented woody perennial.

Historically fragmented and specialized habitats such as granite outcrops are understudied globally unique hot spots of plant evolution. In contrast to predictions based on mainstream population genetic theory, some granite outcrop plants appear to have persisted as very small populations despite prolonged geographic and genetic isolation. Eucalyptus caesia Benth. is a long-lived lignotuberous tree endemic with a naturally fragmented distribution on granite outcrops in south-western Australia. To quantify population to landscape-level genetic structure, we employed microsatellite genotyping at 14 loci of all plants in 18 stands of E. caesia. Sampled stands were characterized by low levels of genetic diversity, small absolute population sizes, localized clonality and strong fine-scale genetic subdivision. There was no significant relationship between population size and levels of heterozygosity. At the landscape scale, high levels of population genetic differentiation were most pronounced among representatives of the two subspecies in E. caesia as originally circumscribed. Past genetic interconnection was evident between some geographic neighbours separated by up to 20 km. Paradoxically, other pairs of neighbouring stands as little as 7 km apart were genetically distinct. There was no consistent pattern of isolation by distance across the 280 km range of E. caesia. Low levels of gene flow, together with strong drift within stands, provide some explanation of the patterns of genetic differentiation we observed. Individual genet longevity via the ability to repeatedly resprout and expand from a lignotuber may enhance the persistence of some woody perennial endemic plants despite small population size, minimal genetic interconnection and low heterozygosity.

Near-neighbour optimal outcrossing in the bird-pollinated Anigozanthos manglesii.

BACKGROUND AND AIMS: In plants, the spatial and genetic distance between mates can influence reproductive success and offspring fitness. Negative fitness consequences associated with the extremes of inbreeding and outbreeding suggest that there will be an intermediate optimal outcrossing distance (OOD), the scale and drivers of which remain poorly understood. In the bird-pollinated Anigozanthos manglesii (Haemodoraceae) we tested (1) for the presence of within-population OOD, (2) over what scale it occurs, and (3) for OOD under biologically realistic scenarios of multi-donor deposition associated with pollination by nectar-feeding birds. METHODS: We measured the impact of mate distance (spatial and genetic) on seed set, fruit size, seed mass, seed viability and germination success following hand pollination from (1) single donors across 0 m (self), <1 m, 1-3 m, 7-15 m and 50 m, and (2) a mix of eight donors. Microsatellite loci were used to quantify spatial genetic structure and test for the presence of an OOD by paternity assignment after multi-donor deposition. KEY RESULTS: Inter-mate distance had a significant impact on single-donor reproductive success, with selfed and nearest-neighbour (<1 m) pollination resulting in only ~50 seeds per fruit, lower overall germination success and slower germination. Seed set was greatest for inter-mate distance of 1-3 m (148 seeds per fruit), thereafter plateauing at ~100 seeds per fruit. Lower seed set following nearest-neighbour mating was associated with significant spatial genetic autocorrelation at this scale. Paternal success following pollination with multiple sires showed a significantly negative association with increasing distance between mates. CONCLUSIONS: Collectively, single- and multi-donor pollinations indicated evidence for a near-neighbour OOD within A. manglesii. A survey of the literature suggests that within-population OOD may be more characteristic of plants pollinated by birds than those pollinated by insects.

Recent range expansion in Australian hummock grasses (Triodia) inferred using genotyping-by-sequencing.

The Australian arid zone (AAZ) has undergone aridification and the formation of vast sandy deserts since the mid-Miocene. Studies on AAZ organisms, particularly animals, have shown patterns of mesic ancestry, persistence in rocky refugia and range expansions in arid lineages. There has been limited molecular investigation of plants in the AAZ, particularly of taxa that arrived in Australia after the onset of aridification. Here we investigate populations of the widespread AAZ grass Triodia basedowii to determine whether there is evidence for a recent range expansion, and if so, its source and direction. We also undertake a dating analysis for the species complex to which T. basedowii belongs, in order to place its diversification in relation to changes in AAZ climate and landscapes. We analyse a genomic single nucleotide polymorphism data set from 17 populations of T. basedowii in a recently developed approach for detecting the signal and likely origin of a range expansion. We also use alignments from existing and newly sequenced plastomes from across Poaceae for analysis in BEAST to construct fossil-calibrated phylogenies. Across a range of sampling parameters and outgroups, we detected a consistent signal of westward expansion for T. basedowii, originating in central or eastern Australia. Divergence time estimation indicates that Triodia began to diversify in the late Miocene (crown 7.0-8.8 million years (Ma)), and the T. basedowii complex began to radiate during the Pleistocene (crown 1.4-2.0 Ma). This evidence for range expansion in an arid-adapted plant is consistent with similar patterns in AAZ animals and likely reflects a general response to the opening of new habitat during aridification. Radiation of the T. basedowii complex through the Pleistocene has been associated with preferences for different substrates, providing an explanation why only one lineage is widespread across sandy deserts.

Wide outcrossing provides functional connectivity for new and old Banksia populations within a fragmented landscape.

Habitat fragmentation affects landscape connectivity, the extent of which is influenced by the movement capacity of the vectors of seed and pollen dispersal for plants. Negative impacts of reduced connectivity can include reduced fecundity, increased inbreeding, genetic erosion and decreased long-term viability. These are issues for not only old (remnant) populations, but also new (restored) populations. We assessed reproductive and connective functionality within and among remnant and restored populations of a common tree, Banksia menziesii R.Br. (Proteaceae), in a fragmented urban landscape, utilising a genetic and graph theoretical approach. Adult trees and seed cohorts from five remnants and two restored populations were genotyped using microsatellite markers. Genetic variation and pollen dispersal were assessed using direct (paternity assignment) and indirect (pollination graphs and mating system characterisation) methods. Restored populations had greater allelic diversity (Ar = 8.08; 8.34) than remnant populations (Ar range = 6.49-7.41). Genetic differentiation was greater between restored and adjacent remnants (FST = 0.03 and 0.10) than all other pairwise comparisons of remnant populations (mean FST = 0.01 ± 0.01; n = 16 P = 0.001). All populations displayed low correlated paternity (rp = 0.06-0.16) with wide-ranging realised pollen dispersal distances (< 1.7 km) and well-connected pollen networks. Here, we demonstrate reproductive and connective functionality of old and new populations of B. menziesii within a fragmented landscape. Due to long-distance pollination events, the physical size of these sites underestimates their effective population size. Thus, they are functionally equivalent to large populations, integrated into a larger landscape matrix.

Persistence and stochasticity are key determinants of genetic diversity in plants associated with banded iron formation inselbergs.

The high species endemism characteristic of many of the world's terrestrial island systems provides a model for studying evolutionary patterns and processes, yet there has been no synthesis of studies to provide a systematic evaluation of terrestrial island systems in this context. The banded iron formations (BIFs) of south-western Australia are ancient terrestrial island formations occurring within a mosaic of alluvial clay soils, sandplains and occasional granite outcropping, across an old, gently undulating, highly weathered, plateau. Notably, these BIFs display exceptionally high beta plant diversity. Here, we address the determinants and consequences of genetic diversity for BIF-associated plant species through a comprehensive review of all studies on species distribution modelling, phylogenetics, phylogeography, population genetics, life-history traits and ecology. The taxa studied are predominantly narrowly endemic to individual or a few BIF ranges, but some have more regional distributions occurring both on and off BIFs. We compared genetic data for these BIF-endemic species to other localised species globally to assess whether the unique history and ancestry of BIF landscapes has driven distinct genetic responses in plants restricted to this habitat. We also assessed the influence of life-history parameters on patterns of genetic diversity. We found that BIF-endemic species display similar patterns of genetic diversity and structure to other species with localised distributions. Despite often highly restricted distributions, large effective population size or clonal reproduction appears to provide these BIF-endemic species with ecological and evolutionary resilience to environmental stochasticity. We conclude that persistence and stochasticity are key determinants of genetic diversity and its spatial structure within BIF-associated plant species, and that these are key evolutionary processes that should be considered in understanding the biogeography of inselbergs worldwide.

Effectiveness of camera traps for quantifying daytime and nighttime visitation by vertebrate pollinators.

Identification of pollen vectors is a fundamental objective of pollination biology. The foraging and social behavior of these pollinators has profound effects on plant mating, making quantification of their behavior critical for understanding the ecological and evolutionary consequences of different pollinators for the plants they visit. However, accurate quantification of visitation may be problematic, especially for shy animals and/or when the temporal and spatial scale of observation desired is large. Sophisticated heat- and movement-triggered motion-sensor cameras ("camera trapping") provide new, underutilized tools to address these challenges. However, to date, there has been no rigorous evaluation of the sampling considerations needed for using camera trapping in pollination research.We measured the effectiveness of camera trapping for identifying vertebrate visitors and quantifying their visitation rates and foraging behavior on Banksia menziesii (Proteaceae). Multiple still cameras (Reconyx HC 500) and a video camera (Little Acorn LTL5210A) were deployed.From 2,753 recorded visits by vertebrates, we identified five species of nectarivorous honeyeater (Meliphagidae) and the honey possum (Tarsipedidae), with significant variation in the species composition of visitors among inflorescences. Species of floral visitor showed significant variation in their time of peak activity, duration of visits, and numbers of flowers probed per visit. Where multiple cameras were deployed on individual inflorescences, effectiveness of individual still cameras varied from 15% to 86% of all recorded visits. Methodological issues and solutions, and the future uses of camera traps in pollination biology, are discussed. Conclusions and wider implications: Motion-triggered cameras are promising tools for the quantification of vertebrate visitation and some aspects of behavior on flowers. However, researchers need to be mindful of the variation in effectiveness of individual camera traps in detecting animals. Pollinator studies using camera traps are in their infancy, and the full potential of this developing technology is yet to be realized.

Seeds in motion: Genetic assignment and hydrodynamic models demonstrate concordant patterns of seagrass dispersal.

Movement is fundamental to the ecology and evolutionary dynamics within species. Understanding movement through seed dispersal in the marine environment can be difficult due to the high spatial and temporal variability of ocean currents. We employed a mutually enriching approach of population genetic assignment procedures and dispersal predictions from a hydrodynamic model to overcome this difficulty and quantify the movement of dispersing floating fruit of the temperate seagrass Posidonia australis Hook.f. across coastal waters in south-western Australia. Dispersing fruit cohorts were collected from the water surface over two consecutive years, and seeds were genotyped using microsatellite DNA markers. Likelihood-based genetic assignment tests were used to infer the meadow of origin for seed cohorts and individuals. A three-dimensional hydrodynamic model was coupled with a particle transport model to simulate the movement of fruit at the water surface. Floating fruit cohorts were mainly assigned genetically to the nearest meadow, but significant genetic differentiation between cohort and most likely meadow of origin suggested a mixed origin. This was confirmed by genetic assignment of individual seeds from the same cohort to multiple meadows. The hydrodynamic model predicted 60% of fruit dispersed within 20 km, but that fruit was physically capable of dispersing beyond the study region. Concordance between these two independent measures of dispersal provides insight into the role of physical transport for long distance dispersal of fruit and the consequences for spatial genetic structuring of seagrass meadows.

Memory for faces in old age: A meta-analysis.

The present meta-analysis investigated the influence of age on face recognition. A total of 19 studies with 79 comparisons of younger and older participants were included. Analyses revealed small to moderate effects for hits, and large effects for false alarms and signal detection theory (SDT) measures. Younger participants outperformed older participants on most face recognition measures. Younger participants made more hits (gu = 0.31) and fewer false alarms (gu = 0.95) and thus had better SDT recognition performance (gu = 1.01) than older participants. These effects were largest for young faces, smaller for mixed-age faces, and smallest for older faces. Furthermore, older participants used a more liberal response criterion, that is, they were more likely to choose a face than younger participants (gu = 0.54). Meta-regression analyses revealed that young faces (vs. mixed-age faces) and longer retention intervals were associated with greater differences between the age groups for hits but not for false alarms. Funnel plot and trim-and-fill analyses indicated the presence of a publication bias. Theoretical implications for future research and for older people as eyewitnesses are outlined. (PsycINFO Database Record

Population genetic analysis reveals barriers and corridors for gene flow within and among riparian populations of a rare plant.

Landscape features and life-history traits affect gene flow, migration and drift to impact on spatial genetic structure of species. Understanding this is important for managing genetic diversity of threatened species. This study assessed the spatial genetic structure of the rare riparian Grevillea sp. Cooljarloo (Proteaceae), which is restricted to a 20 km2 region impacted by mining in the northern sandplains of the Southwest Australian Floristic Region, an international biodiversity hotspot. Within creek lines and floodplains, the distribution is largely continuous. Models of dispersal within riparian systems were assessed by spatial genetic analyses including population level partitioning of genetic variation and individual Bayesian clustering. High levels of genetic variation and weak isolation by distance within creek line and floodplain populations suggest large effective population sizes and strong connectivity, with little evidence for unidirectional gene flow as might be expected from hydrochory. Regional clustering of creek line populations and strong divergence among creek line populations suggest substantially lower levels of gene flow among creek lines than within creek lines. There was however a surprising amount of genetic admixture in floodplain populations, which could be explained by irregular flooding and/or movements by highly mobile nectar-feeding bird pollinators. Our results highlight that for conservation of rare riparian species, avoiding an impact to hydrodynamic processes, such as water tables and flooding dynamics, may be just as critical as avoiding direct impacts on the number of plants.