Spatial Concordance Research Articles

Assessing vertebrate biodiversity in a kelp forest ecosystem using environmental DNA.

Preserving biodiversity is a global challenge requiring data on species’ distribution and abundance over large geographic and temporal scales. However, traditional methods to survey mobile species’ distribution and abundance in marine environments are often inefficient, environmentally destructive, or resource‐intensive. Metabarcoding of environmental DNA (eDNA) offers a new means to assess biodiversity and on much larger scales, but adoption of this approach for surveying whole animal communities in large, dynamic aquatic systems has been slowed by significant unknowns surrounding error rates of detection and relevant spatial resolution of eDNA surveys. Here, we report the results of a 2.5 km eDNA transect surveying the vertebrate fauna present along a gradation of diverse marine habitats associated with a kelp forest ecosystem. Using PCR primers that target the mitochondrial 12S rRNA gene of marine fishes and mammals, we generated eDNA sequence data and compared it to simultaneous visual dive surveys. We find spatial concordance between individual species’ eDNA and visual survey trends, and that eDNA is able to distinguish vertebrate community assemblages from habitats separated by as little as ~60 m. eDNA reliably detected vertebrates with low false‐negative error rates (1/12 taxa) when compared to the surveys, and revealed cryptic species known to occupy the habitats but overlooked by visual methods. This study also presents an explicit accounting of false negatives and positives in metabarcoding data, which illustrate the influence of gene marker selection, replication, contamination, biases impacting eDNA count data and ecology of target species on eDNA detection rates in an open ecosystem.

Abstract 13596: Magnetic Resonance - Derived Pre-contrast T1 Relaxation Time is the Accurate Marker of Diffuse Myocardial Fibrosis in Severe Aortic Valve Disease: A Comparison With Left Ventricular Myocardial Biopsy

Introduction: Diffuse myocardial fibrosis (DFM) is the major mechanism in the pathophysiology of the aortic stenosis and its complications. DMF is detectable by magnetic resonance imaging (MRI) using the T1 mapping technique. Hypothesis: The MRI derived native T1 relaxation time and myocardial extracellular volume fraction (ECV) will be significantly related to the extent of DMF et targeted myocardial left ventricular (LV) biopsy. Methods: The study population consisted of 40 consecutive patients (age 63±8y, 65% males) undergoing surgery for severe aortic stenosis (77.5%), aortic root dilatation (7.5%) or valve regurgitation (15%). All patients underwent MRI-derived T1 mapping and 2D-, 3D speckle tracking-derived strain analysis prior to surgery. The T1 relaxation time was assessed in basal interventricular septum pre and 10 min post contrast administration using the modified Look-Locker Inversion recovery sequence. A LV myocardial biopsy specimen was obtained during surgery from basal interventricular septum under the guidance of the MRI operator to assure spatial concordance with the MRI assessment. The percentage of myocardial collagen was quantified as a ratio of Picrosirius Red-positive area over total sample area using the Image J. Results: The average percentage of myocardial collagen was 22 ± 14.8 %. The average native T1 relaxation time and ECV was 1010 ± 48 ms and 0.288 ± 0.055, respectively. Both native T1 relaxation time with cutoff value of ≥ 1010 ms (Ss=90%, Sp=73%, AUC =0.82) and ECV with cutoff value of ≥ 0.315 (Ss=80%, Sp=90%, AUC =0.85) showed high accuracy to identify extensive (> 30%) myocardial collagen content (Figure 1A, 1B). The native T1 mapping showed significant correlation with LV mass, 2D and 3D global longitudinal strain (all p<0.05) while the ECV did not (p=NS). Conclusions: Native T1 relaxation time is the accurate marker of diffuse myocardial fibrosis with the significant relationship with LV morphology and myocardial function.

Differences in spatial synchrony and interspecific concordance inform guild‐level population trends for aerial insectivorous birds

Many animal species exhibit spatiotemporal synchrony in population fluctuations, which may provide crucial information about ecological processes driving population change. We examined spatial synchrony and concordance among population trajectories of five aerial insectivorous bird species: chimney swift Chaetura pelagica, purple martin Progne subis, barn swallow Hirundo rustica, tree swallow Tachycineta bicolor, and northern rough‐winged swallow Stelgidopteryx serripennis. Aerial insectivores have undergone severe guild‐wide declines that were considered more prevalent in northeastern North America. Here, we addressed four general questions including spatial synchrony within species, spatial concordance among species, frequency of declining trends among species, and geographic location of declining trends. We used dynamic factor analysis to identify large‐scale common trends underlying stratum‐specific annual indices for each species, representing population trajectories shared by spatially synchronous populations, from 46 yr of North American Breeding Bird Survey data. Indices were derived from Bayesian hierarchical models with continuous autoregressive spatial structures. Stratum‐level spatial concordance among species was assessed using cross‐correlation analysis. Probability of long‐term declining trends was compared among species using Bayesian generalized linear models. Chimney swifts exhibited declining trends throughout North America, with less severe declines through the industrialized Mid‐Atlantic and Great Lakes regions. Northern rough‐winged swallows exhibited declining trends throughout the west. Spatial concordance among species was limited, the proportion of declining trends varied among species, and contrary to previous reports, declining trends were not more prevalent in the northeast. Purple martins, barn swallows, and tree swallows exhibited synchrony across smaller spatial scales. The extensive within‐species synchrony and limited concordance suggest that population trajectories of these aerial insectivores are responding to large‐scale but complex and species‐ and region‐specific environmental conditions (e.g. climate, land use). A single driver of trends for aerial insectivores as a guild appears unlikely.

PO2818F- FLUOROMETHYLCHOLINE (18F-FMC) PET/CT AND MAGNETIC RESONANCE SPECTROSCOPY (MRS) IMAGING AND TISSUE BIOMARKERS OF CELL MEMBRANE TURNOVER IN PRIMARY BRAIN GLIOMAS- A PILOT STUDY

INTRODUCTION: Standard contrast enhanced MRI is not reliable for characterising glioma. Choline is a key component of cell membranes; its levels are increased in primary brain tumours, indicating how rapidly tumour cells are dividing. Imaging with 18F-FMC PET and MRS allow choline to be assessed non-invasively, although these imaging biomarkers have not previously been validated against tissue markers of choline metabolism, such as choline kinase (CHK±) from tumour specimens. METHOD: A prospective pilot study of 12 subjects, aged 18-80, with suspected primary supratentorial glioma suitable for biopsy and/or resection and a lesion diameter >2cm, recruited from Neuro-oncology MDT. The MRI protocol was performed at 3T, using a 32 channel head coil. PET/CT was then performed with 285MBq of 18F-FMC injected followed by dedicated brain dynamic list mode acquisition for 45 minutes. During surgery, 4-6 routine stereotactic biopsies were obtained. CHK± immunohistochemistry data is pending and will be presented in full at the conference. RESULTS: Preliminary data from 6 patients suggests spatial concordance between high 18F-FMC uptake on PET and more elevated choline/creatine ratio. Tissue data from 4 patients (2 low grade, 2 transforming gliomas) shows areas of high choline on imaging correlate with gliosis and macrophage infiltration, but not proliferative indices. CONCLUSION: Preliminary findings suggest choline PET and MRS detect inflammatory infiltrates rather than regions of high cellular proliferation.

NIMG-3118F-METHYLCHOLINE PET/CT AND MAGNETIC RESONANCE SPECTROSCOPY IMAGING AND TISSUE BIOMARKERS OF CELL MEMBRANE TURNOVER IN PRIMARY BRAIN GLIOMAS - A PILOT STUDY

BACKGROUND: Choline containing compounds are key components of cell membranes; their metabolism important in membrane turnover, and therefore cellular proliferation. Choline elevation has been reported as a marker of aggressive glioma phenotype in numerous in vivo magnetic resonance spectroscopy (MRS) studies, and more recently 18F-methylcholine-PET has been applied to glioma characterisation. This preliminary study aims to examine the relationship between MRS and PET imaging choline measures in defined tumour regions, and validate these against tissue biomarkers of choline metabolism and proliferation. METHODS: A prospective pilot study of 12 subjects, aged 18-80, with suspected primary supratentorial glioma of varying grades suitable for biopsy/resection. An MRI protocol, including multivoxel MRS (TE = 30ms; TR = 1500ms), was acquired at 3T using a 32 channel head coil; PET/CT was performed with 285MBq of 18F-methylcholine with a dedicated 45 minute brain dynamic list mode acquisition. Stereotactic biopsies were obtained using neuronavigation from low and high choline areas identified on imaging, fused with high resolution structural images. RESULTS: Preliminary data from 8 patients suggests spatial concordance between high choline uptake on PET and elevated MRS choline/creatine ratios. Tissue from 4 patients (2 WHO grade-II, 2 grade-III) showed high choline areas on imaging correlate with reactive gliosis and macrophage infiltrates, but no mitotic activity or denser cellularity. In one predominantly grade II astrocytoma, areas of elevated uptake on PET showed denser cellularity and mitoses, in keeping with early malignant progression. CONCLUSIONS: Preliminary findings suggest choline PET and MRS may detect regions of inflammatory infiltrate, rather than showing a simple relationship with high tumour cellular proliferation. In one case, elevated choline uptake on PET corresponded to early focal malignant transformation. Whilst these imaging methods show continued promise for glioma characterisation, further validation against tissue enzymatic and genetic biomarkers, and clinical outcomes is essential for their rational translation into wider clinical practice.

Dentatorubrothalamic tract localization with postmortem MR diffusion tractography compared to histological 3D reconstruction.

Diffusion-weighted imaging (DWI) tractography is a technique with great potential to characterize the in vivo anatomical position and integrity of white matter tracts. Tractography, however, remains an estimation of white matter tracts, and false-positive and false-negative rates are not available. The goal of the present study was to compare postmortem tractography of the dentatorubrothalamic tract (DRTT) by its 3D histological reconstruction, to estimate the reliability of the tractography algorithm in this specific tract. Recent studies have shown that the cerebellum is involved in cognitive, language and emotional functions besides its role in motor control. However, the exact working mechanism of the cerebellum is still to be elucidated. As the DRTT is the main output tract it is of special interest for the neuroscience and clinical community. A postmortem human brain specimen was scanned on a 7T MRI scanner using a diffusion-weighted steady-state free precession sequence. Tractography was performed with PROBTRACKX. The specimen was subsequently serially sectioned and stained for myelin using a modified Heidenhain–Woelke staining. Image registration permitted the 3D reconstruction of the histological sections and comparison with MRI. The spatial concordance between the two modalities was evaluated using ROC analysis and a similarity index (SI). ROC curves showed a high sensitivity and specificity in general. Highest measures were observed in the superior cerebellar peduncle with an SI of 0.72. Less overlap was found in the decussation of the DRTT at the level of the mesencephalon. The study demonstrates high spatial accuracy of postmortem probabilistic tractography of the DRTT when compared to a 3D histological reconstruction. This gives hopeful prospect for studying structure–function correlations in patients with cerebellar disorders using tractography of the DRTT.Electronic supplementary materialThe online version of this article (doi:10.1007/s00429-015-1115-7) contains supplementary material, which is available to authorized users.

Spatial discordance and phase reversals during alternate pacing in discrete-time kinematic and cardiomyocyte ionic models.

Alternans, a beat-to-beat alternation in the cardiac action potential duration (APD), is a dynamical instability linked with the initiation of arrhythmias and sudden cardiac death, and arises via a period-doubling bifurcation when myocytes are stimulated at fast rates. In this study, we analyze the stability of a propagating electrical wave in a one-dimensional cardiac myocyte model in response to an arrhythmogenic rhythm known as alternate pacing. Using a discrete-time kinematic model and complex frequency (Z) domain analysis, we derive analytical expressions to predict phase reversals and spatial discordance in the interbeat interval (IBI) and APD, which, importantly, cannot be predicted with a model that neglects the influence of cell coupling on repolarization. We identify key dimensionless parameters that determine the transition from spatial concordance to discordance. Finally, we show that the theoretical predictions agree closely with numerical simulations of an ionic myocyte model, over a wide range of parameters, including variable IBI, altered ionic current gating, and reduced cell coupling. We demonstrate a novel approach to predict instability in cardiac tissue during alternate pacing and further illustrate how this approach can be generalized to more detail models of myocyte dynamics.

Integrating multiple species connectivity and habitat quality into conservation planning for coral reefs

Incorporating connectivity into the design of marine protected areas (MPAs) has met with conceptual, theoretical, and practical challenges, which include: 1) the need to consider connectivity for multiple species with different dispersal abilities, and 2) the role played by variable habitat quality in determining the spatial patterns of connectivity. We propose an innovative approach, combining biophysical modeling with a routinely‐used tool for marine‐reserve design (Marxan), to address both challenges by using ecologically‐informed connectivity parameters. We showed how functional demographic connectivity for four candidate reef‐associated species with varying dispersal abilities and a suite of connectivity metrics weighted by habitat quality can be used to set conservation objectives and inform MPA placement. Overall, the strength of dispersal barriers varied across modeled species and, also across species, we found a lack of spatial concordance of reefs that were high‐quality sources, self‐persistent, and stepping‐stones. Including spatially‐heterogeneous habitat quality made a considerable difference to connectivity patterns, significantly reducing the potential reproductive output from many reefs. We also found that caution is needed in combining connectivity data from modeled species into multi‐species matrices, which do not perform reliably as surrogates for all connectivity metrics of individual species. We then showed that restricting the habitat available for conservation has an inequitable impact on different connectivity objectives and species, with greatest impact on betweenness centrality and long‐distance dispersers. We used Brazilian coral reefs as a case study but our approach is applicable to both marine and terrestrial conservation planning, and offers a holistic way to design functionally‐connected reserves to tackle the complex issues relevant to planning for persistence.

Deep and wide valleys drive nested phylogeographic patterns across a montane bird community.

Montane species distributions interrupted by valleys can lead to range fragmentation, differentiation and ultimately speciation. Paleoclimatic fluctuations may accentuate or reduce such diversification by temporally altering the extent of montane habitat and may affect species differentially. We examined how an entire montane bird community of the Western Ghats--a linear, coastal tropical mountain range--responds to topographic valleys that host different habitats. Using genetic data from 23 species (356 individuals) collected across nine locations, we examined if different species in the community reveal spatial concordance in population differentiation, and whether the timing of these divergences correlate with climatic events. Our results reveal a nested effect of valleys, with several species (10 of 23) demonstrating the oldest divergences associated with the widest and deepest valley in the mountain range, the Palghat Gap. Further, a subset of these 10 species revealed younger divergences across shallower, narrower valleys. We recovered discordant divergence times for all valley-affected montane birds, mostly in the Pleistocene, supporting the Pliestocene-pump hypotheses and highlighting the role of climatic fluctuations during this period in driving species evolution. A majority of species remain unaffected by valleys, perhaps owing to geneflow or extinction-recolonization dynamics. Studying almost the entire community allowed us to uncover a range of species' responses, including some generalizable and other unpredicted patterns.

Connectivity-based segmentation of the periaqueductal gray matter in human with brainstem optimized diffusion MRI.

The periaqueductal gray matter (PAG) is a midbrain structure, involved in key homeostatic neurobiological functions, such as pain modulation and cardiorespiratory control. Animal research has identified four subdivisional columns that differ in both connectivity and function. Until now these findings have not been replicated in humans. This study used high‐resolution brainstem optimized diffusion magnetic resonance imaging and probabilistic tractography to segment the human PAG into four subdivisions, based on voxel connectivity profiles. We identified four distinct subdivisions demonstrating high spatial concordance with the columns of the animal model. The resolution of these subdivisions for individual subjects permitted detailed examination of their structural connectivity without the requirement of an a priori starting location. Interestingly patterns of forebrain connectivity appear to be different to those found in nonhuman studies, whereas midbrain and hindbrain connectivity appears to be maintained. Although there are similarities in the columnar structure of the PAG subdivisions between humans and nonhuman animals, there appears to be different patterns of cortical connectivity. This suggests that the functional organization of the PAG may be different between species, and as a consequence, functional studies in nonhumans may not be directly translatable to humans. This highlights the need for focused functional studies in humans. Hum Brain Mapp 36:3459–3471, 2015. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Community-wide spatial and temporal discordances of seed-seedling shadows in a tropical rainforest.

Several factors decrease plant survival throughout their lifecycles. Among them, seed dispersal limitation may play a major role by resulting in highly aggregated (contagious) seed and seedling distributions entailing increased mortality. The arrival of seeds, furthermore, may not match suitable environments for seed survival and, consequently, for seedling establishment. In this study, we investigated spatio-temporal patterns of seed and seedling distribution in contrasting microhabitats (bamboo and non-bamboo stands) from the Brazilian Atlantic Forest. Spatial distribution patterns, spatial concordance between seed rain and seedling recruitment between subsequent years in two fruiting seasons (2004–2005 and 2007–2009), and the relation between seeds and seedlings with environmental factors were examined within a spatially-explicit framework. Density and species richness of both seeds and seedlings were randomly distributed in non-bamboo stands, but showed significant clustering in bamboo stands. Seed and seedling distributions showed across-year inconsistency, suggesting a marked spatial decoupling of the seed and seedling stages. Generalized linear mixed effects models indicated that only seed density and seed species richness differed between stand types while accounting for variation in soil characteristics. Our analyses provide evidence of marked recruitment limitation as a result of the interplay between biotic and abiotic factors. Because bamboo stands promote heterogeneity in the forest, they are important components of the landscape. However, at high densities, bamboos may limit recruitment for the plant community by imposing marked discordances of seed arrival and early seedling recruitment.

Abstract T P172: Temporal Correlation Perfusion Mapping Introduces a Robust and Rapid Method of Identifying Penumbra in Acute Ischemic Stroke

Background and Purpose: We implemented new temporal correlation perfusion (TCP) analyses that were rapid, model-free and automated. We assessed the reliability and robustness of TCP mapping compared to the standard method of time-to-peak (TTP) mapping used in the identification of perfusion deficit in acute ischemic stroke. Methods: A model-free and automated method of detecting aberrant perfusion was developed to create TCP maps based on the maximum temporal correlations of the signal time-intensity waveforms following contrast injection. For validation purposes, the TCP and TTP maps from IV tPA treated ischemic stroke (n=20) and untreated imaging negative TIA (n=20) patients were visually read for presence of perfusion deficit by two expert readers blinded to the clinical diagnosis. Next, the perfusion lesion volumes on the TCP and TTP maps were segmented by two other experts and were compared for inter-rater reliability, volumetric and spatial concordance, and contrast to noise ratio. Pearson’s r correlation and t-test for TCP and TTP maps were used with degrees of freedom indicated by parentheses. Additionally, inter-rater reliability and contrast to noise ratios were compared. Results: Both readers identified all of the subjects (40/40) correctly as either having perfusion deficits or not based on the TCP maps alone. Improved rater inter-reliability in lesion volume segmentation was found in TCP compared to TTP maps, with high correlation in lesion volume (r (18) = 0.85) and spatial overlap (91.1+/-9.5%) between TCP and TTP maps. Better contrast to noise ratio in lesions segmented with TCP compared to TTP maps (t (19) = 14.9, p<0.0001) was demonstrated which led to increased lesion conspicuity. Conclusions: We conclude that temporal correlation mapping holds promise as a reliable and more robust method for perfusion deficit identification as demonstrated by correct identification and improved lesion segmentation compared to current standard methods.

Spatial relationship between fast and slow components of ictal activities and interictal epileptiform discharges in epileptic spasms

ObjectiveWe analyzed the spatial distribution and concordance of fast (>10Hz) and slow (<5Hz) electroencephalogram (EEG) components of ictal activities and interictal epileptiform discharges (IIED) recorded by intracranial video EEG (IVEEG) in children with epileptic spasms (ES). MethodsWe studied eight children with ES, who underwent IVEEG before resective surgery for epilepsy. We quantified the root-mean-square (RMS) amplitude of the fast and slow components of ictal activities during ES and IIED. We compared the concordance between the spatial distributions of the fast and slow components of ES and IIED. ResultsThere was a larger concordance between the spatial distributions of the fast and slow components in IIED than in ES (p=0.0206 and 0.0401). ConclusionsThe spatial concordance between the fast and slow EEG components was significantly different between ES and IIED. SignificanceThe mechanisms underlying the generation of slow EEG components may differ between ES and IIED. The slow EEG components of ES might indicate an extensive epileptic network involving remote symptomatic zones for ES in either the cortical or subcortical areas. The high spatial concordance between the fast and slow components of IIED suggests the involvement of a local inhibitory process within the epileptic cortex.

Spatial community concordance of summer phytoplankton and profundal macroinvertebrates in boreal lakes

Reliance of profundal benthic macroinvertebrate assemblages on epilimnetic algal production — a key element of pelagic–benthic coupling — is a well-recognized phenomenon in the literature but the details are still poorly understood. In particular, the importance of taxonomic composition of algal communities and associated qualitative aspects of the settling material to benthic invertebrates is poorly known. We addressed this issue by investigating concordance of summer phytoplankton and profundal macroinvertebrate community composition using data from 47 boreal lakes. We examined community variation and environmental correlates of phytoplankton and macroinvertebrates with nonmetric multidimensional scaling ordinations. We also used cluster analysis to group sites according to their macroinvertebrate assemblages and evaluated the differences in phytoplankton composition and class-specific relative abundance among the clusters. Community concordance was evaluated with Procrustes rotation and partial Mantel tests, using oxygen concentration and phytoplankton biomass — the main drivers of macroinvertebrate community structure — as controlling factors. Procrustes and Mantel tests suggested congruence between macroinvertebrate and summer phytoplankton community composition. The concordance remained significant even after controlling for oxygen and biomass, by partial Mantel tests, suggesting a unique effect of phytoplankton species composition on macroinvertebrate assemblages. The four groups of lakes clustered by their macroinvertebrate assemblages also differed significantly in their phytoplankton taxa composition, and there were among-cluster differences in relative abundance of the seven most abundant phytoplankton classes. Our findings of community concordance of phytoplankton and profundal macroinvertebrates suggest a functional dependency of these two components, but further studies are needed to verify the actual causal mechanisms.

18F]-Fluoromisonidazole Positron Emission Tomography/Computed Tomography Visualization of Tumor Hypoxia in Patients With Chordoma of the Mobile and Sacrococcygeal Spine

To investigate [18F]-fluoromisonidazole positron emission tomography/computed tomography (FMISO-PET/CT) detection of targetable hypoxic subvolumes (HSVs) in chordoma of the mobile or sacrococcygeal spine. A prospective, pilot study of 20 patients with primary or locally recurrent chordoma of the mobile or sacrococcygeal spine treated with proton or combined proton/photon radiation therapy (RT) with or without surgery was completed. The FMISO-PET/CT was performed before RT and after 19.8-34.2 GyRBE (relative biologic effectiveness). Gross tumor volumes were delineated and HSVs defined including voxels with standardized uptake values ≥1.4 times the muscle mean. Clinical characteristics and treatments received were compared between patients with and without HSVs. The FMISO-PET/CT detected HSVs in 12 of 20 patients (60%). Baseline and interval HSV spatial concordance varied (0%-94%). Eight HSVs were sufficiently large (≥5 cm(3)) to potentially allow an intensity modulated proton therapy boost. Patients with HSVs had significantly larger gross tumor volumes (median 410.0 cm(3) vs 63.4 cm(3); P=.02) and were significantly more likely to have stage T2 tumors (5 of 12 vs 0 of 8; P=.04). After a median follow-up of 1.8 years (range, 0.2-4.4 years), a local recurrence has yet to be observed. Three patients developed metastatic disease, 2 with HSVs. Detection of targetable HSVs by FMISO-PET/CT within patients undergoing RT with or without surgery for treatment of chordoma of the mobile and sacrococcygeal spine is feasible. The study's inability to attribute interval HSV changes to treatment, rapidly changing hypoxic physiology, or imaging inconsistencies is a limitation. Further study of double-baseline FMISO-PET/CT and hypoxia-directed RT dose escalation, particularly in patients at high risk for local recurrence, is warranted.

A determination of the spatial concordance between Lyme disease incidence and habitat probability of its primary vector Ixodes scapularis (black-legged tick).

The spatial distribution of Ixodes scapularis, the most common tick vector of the bacterium Borrelia burgdorferi, the cause of Lyme disease in humans, has not been studied previously in Texas, United States of America. It has only rarely been reported in this state, so its local, spatial relationship to the distribution of this disease is unknown. From an epidemiological perspective, one would tend to hypothesise that there should be a high degree of spatial concordance between habitat suitability for the tick and incidence of the disease. Both maximum-entropy modelling of the tick's habitat probability and modelling of human incidence of Lyme disease using spatially adaptive filters provide reliable portrayals of the spatial distributions of these phenomena. Even though rates of human cases of Lyme disease as well as rates of Ixodes ticks infected with Borrelia bacteria are both relatively low in Texas, the best data currently available indicate that the assumption of high levels of spatial concordance would not be correct in Texas (Kappa coefficient of agreement = 0.039). It will take substantially more data to provide conclusive findings and to understand the results reported here, but this study provides an approach to begin understanding the discrepancy.

Spatial and temporal patterns of diversification on the Amazon: A test of the riverine hypothesis for all diurnal primates of Rio Negro and Rio Branco in Brazil

The role of Amazonian rivers as drivers of speciation through vicariance remains controversial. Here we explore the riverine hypothesis by comparing spatial and temporal concordances in pattern of diversification for all diurnal primates of Rio Negro and its largest tributary, Rio Branco. We built a comprehensive comparative phylogenetic timetree to identify sister lineages of primates based on mitochondrial cytochrome b DNA sequences from 94 samples, including 19 of the 20 species of diurnal primates from our study region and 17 related taxa from elsewhere. Of the ten primate genera found in this region, three had populations on opposite banks of Rio Negro that formed reciprocally monophyletic clades, with roughly similar divergence times (Cebus: 1.85Ma, HPD 95% 1.19–2.62; Callicebus: 0.83Ma HPD 95% 0.36–1.32, Cacajao: 1.09Ma, 95% HPD 0.58–1.77). This also coincided with time of divergence of several allopatric species of Amazonian birds separated by this river as reported by other authors. Our data offer support for the riverine hypothesis and for a Plio-Pleistocene time of origin for Amazonian drainage system. We showed that Rio Branco was an important geographical barrier, limiting the distribution of six primate genera: Cacajao, Callicebus, Cebus to the west and Pithecia, Saguinus, Sapajus to the east. The role of this river as a vicariant agent however, was less clear. For example, Chiropotes sagulata on the left bank of the Rio Branco formed a clade with C. chiropotes from the Amazonas Department of Venezuela, north of Rio Branco headwaters, with C. israelita on the right bank of the Rio Branco as the sister taxon to C. chiropotes+C. sagulata. Although we showed that the formation of the Rio Negro was important in driving diversification in some of our studied taxa, future studies including more extensive sampling of markers across the genome would help determine what processes contributed to the evolutionary history of the remaining primate genera.

Refugia within refugia - patterns in endemism and genetic divergence are linked to Late Quaternary climate stability in the Iberian Peninsula

In Europe, southern peninsulas served as major refugia during Pleistocene cold periods. However, growing evidence has revealed complex patterns of glacial survival within these southern regions, with multiple glacial refugia within each larger refugial area. We investigated the extent to which patterns of endemism and phylogeographic are concordant across animal species in the Iberian Peninsula, one of the most important unglaciated areas in Europe during the Pleistocene, can be explained in terms of climatic stability. We found that historical climatic stability (notably climate velocity measures integrating macroclimatic shifts with local spatial topoclimate gradients) was often among the most important predictors of endemic species richness for different taxonomic groups using models that also incorporated measures of modern climate. Furthermore, for some taxonomic groups, climatic stability was also correlated with patterns of spatial concordance in interpopulation genetic divergence across multiple taxa, and private haplotypes were more frequently found in relatively stable areas. Overall, our results suggest that both endemism patterns and cross-taxa concordant phylogeographic patterns across the Iberian Peninsula to some extent are linked to spatial variation in Late Quaternary climate stability, in agreement with the proposed ‘refugia-within-refugia’ scenario. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 13–28.

The tradeoff and synergy between ecosystem services in the Grain-for-Green areas in Northern Shaanxi, China

As an important part of the strategy of Western development, the Grain-for-Green Program (GFGP) was initiated to protect the environment and mitigate disasters. Ecosystem services and their dynamics are considered emerging features of ecological quality and the change in direction by many scholars and practitioners. Extending from ecosystem services (ESs) modeling, we propose a simple and feasible framework for quantitatively assessing the benefits and equilibrium of the consequences of the GFGP. Our starting evaluation shows that ESs has changed dramatically in the GFGP area. By fitting pair-wise ESs’ spatial concordances at the grid-cell level, we have revealed the tradeoffs between provisioning and regulating services and the synergies between the regulating services. The analysis of the variability of the relationship between ESs on different land cover types clearly identifies the vegetation that has produced exceptionally strong ESs. Our findings suggest that quantifying the interactions between ESs may improve the ecosystem-based management practices and support policy-making to address the challenges of the sustainable use of natural resources. The framework designed for regional-scale analysis can help in clearly understanding the interrelations of ESs and make natural resources related decisions more effective and efficient, although this framework still needs to move beyond these fundamental and illustrative analyses to more fully explain the synergies and tradeoffs.

Bottom-up control regulates patterns of fish connectivity and assemblage structure in coastal wetlands

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 500:175-186 (2014) - DOI: https://doi.org/10.3354/meps10671 Bottom-up control regulates patterns of fish connectivity and assemblage structure in coastal wetlands Ben Davis*, Carlo Mattone, Marcus Sheaves Centre for Tropical Water & Aquatic Ecosystem Research, Estuary & Tidal Wetland Ecosystems Research Group, School of Marine & Tropical Biology, James Cook University, Townsville, Queensland 4811, Australia *Corresponding author: benjamin.davis@my.jcu.edu.au ABSTRACT: We examined the potential for patterns in invertebrate prey distribution to act as a key driver of fish distribution across a coastal wetland system. Seascape and metacommunity approaches recognise that faunal assemblages in coastal and freshwater systems are structured by responses to multi-scale connectivity and local environmental conditions. However, we currently have a poor understanding of how different groups of aquatic organisms affect each other’s distribution. Most fish in freshwater and coastal wetland systems feed predominantly on benthic invertebrates and zooplankton. To investigate the extent to which these invertebrate taxa exert control over fish distribution, we sampled fish, benthic invertebrate and zooplankton assemblages across 13 inter-connected pools on a salt-marsh in North Queensland, Australia. We found strong and inter-annually consistent spatial concordances among the 3 faunal components, characterised by higher densities of benthic invertebrates and zooplankton in pools at lower elevations on the salt-marsh—reflected by high densities of planktivorous and benthivorous fish, and lower densities of benthic invertebrates and zooplankton in pools at higher elevations—reflected by dominance of fish species trophically de-coupled from these taxa (detritivores, insectivores, and herbivores). Further supporting the idea of trophic linkages, the 2 most invertebrate-rich pools also harboured the greatest densities of benthivorous and zooplanktivorous fish, which in turn attracted the wetland piscivores Lates calcarifer and Megalops cyprinoides. This is indicative of bottom-up forcing acting across 3 trophic levels, a process that is likely facilitated by the frequent tidal connections among pools, which allows for regular redistribution of fish. Prey availability should be considered as a key component of the spatial ecology processes that shape fish assemblages across coastal and freshwater wetland systems. KEY WORDS: Seascape · Metacommunity · Nursery grounds · Estuary · Barramundi · Predator–prey · Biotic interactions · Tidal wetland · Food availability · Food web Full text in pdf format Erratum PreviousNextCite this article as: Davis B, Mattone C, Sheaves M (2014) Bottom-up control regulates patterns of fish connectivity and assemblage structure in coastal wetlands. Mar Ecol Prog Ser 500:175-186. https://doi.org/10.3354/meps10671 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 500. Online publication date: March 17, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.