The sampling and estimation of marine paleodiversity patterns: implications of a Pliocene model

Abstract.-Data that accurately capture the spatial structure of biodiversity are required for many paleobiological questions, from assessments of changing provinciality and the role of geographic ranges in extinction and originations, to estimates of global taxonomic or morphological diversity through time. Studies of temporal changes in diversity and global biogeographic patterns have attempted to overcome fossil sampling biases through sampling standardization protocols, but such approaches must ultimately be limited by available literature and museum collections. One approach to evaluating such limits is to compare results from the fossil record with models of past diversity patterns informed by modern relationships between diversity and climatic factors. Here we use present-day patterns for marine bivalves, combined with data on the geologic ages and distributions of extant taxa, to develop a model for Pliocene diversity patterns, which is then compared with diversity patterns retrieved from the literature as compiled by the Paleobiology Database (PaleoDB). The published Pliocene bivalve data (PaleoDB) lack the first-order spatial structure required to generate the modern biogeography within the time available (,3 Myr). Instead, the published data (raw and standardized) show global diversity maxima in the Tropical West Atlantic, followed closely by a peak in the cooltemperate East Atlantic. Either today's tropical West Pacific diversity peak, double that of any other tropical region, is a purely Pleistocene phenomenon-highly unlikely given the geologic ages of extant genera and the topology of molecular phylogenies-or the paleontological literature is such a distorted sample of tropical Pliocene diversity that current sampling standardization methods cannot compensate for existing biases. A rigorous understanding of large-scale spatial and temporal diversity patterns will require new approaches that can compensate for such strong bias, presumably by drawing more fully on our understanding of the factors that underlie the deployment of diversity today

Oil disturbance reduces infaunal family richness but does not affect phylogenetic diversity

Infaunal organisms are susceptible to disturbances such as hypoxia and sediment contamination; changes in infaunal community structure are therefore often used as indicators of anthropogenic disturbance. Susceptibility to disturbance varies across taxa, either due to physiological factors or to behaviors or functional roles that increase exposure. Both sources of variability are likely to be heritable and shared among related taxa. Thus, we would expect oil disturbance to disproportionately affect related taxa and therefore decrease phylogenetic diversity (PD). We test this hypothesis for a shallow water marine infaunal community using a simulation approach that iteratively removes clades with shared vulnerability to oil exposure. Infauna were sampled at two sites in the Chandeleur Islands, LA, that reflect different exposures to crude oil after the Deepwater Horizon event. Seagrass and adjacent bare sediment habitats were sampled in 2015, 5 years after initial oil exposure, and again in 2016 after an acute re-oiling event. We found that strong correlation between PD and family richness masked any detectable PD patterns with oil exposure. For our full community tree, sensitivity analysis indicated that the removal of larger clades did not disproportionately reduce PD, against our prediction. For this pair of sites, PD did not provide a better metric for assessing the impacts of oil exposure than family richness alone. It is possible, however, that finer-scale taxonomic resolution of infaunal communities may better decouple PD from taxonomic richness. More work is needed to fully evaluate the impacts of disturbance on PD

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Beyond Bergmann's rule: size-latitude relationships in marine Bivalvia world-wide. Global Ecology and Biogeography 22: 173–183

ABSTRACT Aim Variations in body size are well established for many taxa of endotherms and ectotherms, but remain poorly documented for marine invertebrates. Here we explore how body size varies with latitude, temperature and productivity for a major marine invertebrate class, the Bivalvia. Location Continental shelves world-wide. Methods We used regression models to assess univariate relationships between size and latitude as well as multivariate relationships between size, latitude and environmental parameters (mean and seasonality in temperature and mean productivity). The dataset consisted of 4845 species in 59 families from shelf depths at all latitudes in the Pacific and Atlantic oceans. We also used Blomberg's K to assess whether size-latitude relationships show phylogenetic signal, and test whether functional groups based on feeding mode, substrate relationships, mobility and fixation can account for observed size-latitude trends. Results Size-latitude trends are taxonomically and geographically common in bivalves, but vary widely in sign and strength -no simple explanations based on environmental parameters, phylogeny or functional group hold across all families. Perhaps most importantly, we found that the observed trends vary considerably between hemispheres and among coastlines. Main conclusions Broadly generalizable macroecological patterns in interspecific body size may not exist for marine invertebrates. Although size-latitude trends occur in many bivalve lineages, the underlying mechanisms evidently differ among regions and/or lineages. Fully understanding macroecological patterns requires truly global datasets as well as information about the evolutionary history of specific lineages and regions

Climate hindcasts: exploring the disjunct distribution of Diopatra biscayensis

The ecosystem engineer onuphid polychaete Diopatra biscayensis has a continuous population in the Bay of Biscay from the Cantabria coast in Spain to southern Brittany in France. A group of disjunct populations also are found in the English Channel, separated from the Biscay population by more than 400 coastal kilometers. It remains unclear whether D. biscayensis is native to the Bay of Biscay; it is also debated whether the disjunct populations in the English Channel are relics of a formerly continuous population, or the product of recent introductions through aquaculture. Here, we use climate hindcasts to explore hypotheses about the D. biscayensis historical distribution in Europe. If D. biscayensis is native, its range would have been restricted to southern Iberia and the Mediterranean during the Last Glacial Maximum (21,000 BP). However, the species is completely absent from both regions today, further supporting its interpretation as a non-native species. If it was historically present in Europe, the climate hindcasts are congruent with range contraction in the Last Glacial Maximum (21,000 BP), expansion in the Mid-Holocene Warm Period (6000 BP), and contraction again in the past 1000 years (850–1850), prior to the first reports of D. biscayensis on the Spanish and French Atlantic coasts. However, the simulations do not support there being climatic refugia along the English Channel coast that would account for the existence of relic populations. Taken together, the evidence suggests that D. biscayensis has been introduced to the Bay of Biscay, and that disjunct populations in the English Channel are the result of recent transport through human activities, perhaps aquaculture

Origination and Immigration Drive Latitudinal Gradients in Marine Functional Diversity

Global patterns in the functional attributes of organisms are critical to understanding biodiversity trends and predicting biotic responses to environmental change. In the first global marine analysis, we find a strong decrease in functional richness, but a strong increase in functional evenness, with increasing latitude using intertidal-to-outer-shelf bivalves as a model system (N = 5571 species). These patterns appear to be driven by the interplay between variation in origination rates among functional groups, and latitudinal patterns in origination and range expansion, as documented by the rich fossil record of the group. The data suggest that (i) accumulation of taxa in spatial bins and functional categories has not impeded continued diversification in the tropics, and (ii) extinctions will influence ecosystem function differentially across latitudes.</p

Data from: The sampling and estimation of marine paleodiversity patterns: implications of a Pliocene model

Data that accurately capture the spatial structure of biodiversity are required for many paleobiological questions, from assessments of changing provinciality and the role of geographic ranges in extinction and originations, to estimates of global taxonomic or morphological diversity through time. Studies of temporal changes in diversity and global biogeographic patterns have attempted to overcome fossil sampling biases through sampling standardization protocols, but such approaches must ultimately be limited by available literature and museum collections. One approach to evaluating such limits is to compare results from the fossil record with models of past diversity patterns informed by modern relationships between diversity and climatic factors. Here we use present-day patterns for marine bivalves, combined with data on the geologic ages and distributions of extant taxa, to develop a model for Pliocene diversity patterns, which is then compared with diversity patterns retrieved from the literature as compiled by the Paleobiology Database (PaleoDB). The published Pliocene bivalve data (PaleoDB) lack the first-order spatial structure required to generate the modern biogeography within the time available (<3 Myr). Instead, the published data (raw and standardized) show global diversity maxima in the Tropical West Atlantic, followed closely by a peak in the cool-temperate East Atlantic. Either today's tropical West Pacific diversity peak, double that of any other tropical region, is a purely Pleistocene phenomenon—highly unlikely given the geologic ages of extant genera and the topology of molecular phylogenies—or the paleontological literature is such a distorted sample of tropical Pliocene diversity that current sampling standardization methods cannot compensate for existing biases. A rigorous understanding of large-scale spatial and temporal diversity patterns will require new approaches that can compensate for such strong bias, presumably by drawing more fully on our understanding of the factors that underlie the deployment of diversity today

Data from: Nonlinear thermal gradients shape broad-scale patterns in geographic range size and can reverse Rapoport’s rule

Aim: Species living at latitudes that have greater annual temperature variations are expected to achieve broader geographic ranges than species living at latitudes that have smaller annual temperature variations, generating a positive relationship between range size and latitude (Rapoport's rule). However, this prediction fails to take into account the greater latitudinal extent of tropical temperatures relative to those at higher latitudes. Here we model the contributions of the broader latitudinal extent of equal-temperature habitats at low latitudes and the greater annual temperature variation at high latitudes to the range size–latitude relationship, and test whether the latitudinal variation in geographic range size in marine bivalves can be explained by models that account for both annual temperature variation and the steepness of latitudinal thermal gradients. Location: Western Pacific, eastern Pacific and western Atlantic. Methods: We use a null model where geographic ranges are placed on the ocean surface independently of thermal gradients, and a range-expansion model where the minimum and maximum temperatures encompassed by the geographic range of a species (macroecological thermal ranges) are positively related to annual temperature minima and maxima at the location where the species originated. We compare results with a database containing 40,820 occurrences of 4760 marine bivalve species. Result: Models incorporating temperature-limited range expansion along realistic thermal gradients predict an inverse relationship between range size and latitude, in opposition to Rapoport's rule. The distribution patterns of marine bivalves match this prediction. Main conclusions: The poleward trend in latitudinal range size is determined by the nonlinearity of the latitudinal gradient of temperature minima and maxima and less by the latitudinal gradient of the local seasonal range in temperatures. Although tropical species do have narrower macroecological thermal ranges than high-latitude species, the nearly constant temperatures over wide areas of the tropics allow tropical species to achieve broad latitudinal ranges

Origination and Immigration Drive Latitudinal Gradients in Marine Functional Diversity

<div><p>Global patterns in the functional attributes of organisms are critical to understanding biodiversity trends and predicting biotic responses to environmental change. In the first global marine analysis, we find a strong decrease in functional richness, but a strong increase in functional evenness, with increasing latitude using intertidal-to-outer-shelf bivalves as a model system (N = 5571 species). These patterns appear to be driven by the interplay between variation in origination rates among functional groups, and latitudinal patterns in origination and range expansion, as documented by the rich fossil record of the group. The data suggest that (i) accumulation of taxa in spatial bins and functional categories has not impeded continued diversification in the tropics, and (ii) extinctions will influence ecosystem function differentially across latitudes.</p></div