Trophic interactions will expand geographically but be less intense as oceans warm

Interactions among species are likely to change geographically due to climate-driven species range shifts and in intensity due to physiological responses to increasing temperatures. Marine ectotherms experience temperatures closer to their upper thermal limits due to the paucity of temporary thermal refugia compared to those available to terrestrial organisms. Thermal limits of marine ectotherms also vary among species and trophic levels, making their trophic interactions more prone to changes as oceans warm. We assessed how temperature affects reef fish trophic interactions in the Western Atlantic and modeled projections of changes in fish occurrence, biomass, and feeding intensity across latitudes due to climate change. Under ocean warming, tropical reefs will experience diminished trophic interactions, particularly herbivory and invertivory, potentially reinforcing algal dominance in this region. Tropicalization events are more likely to occur in the northern hemisphere, where feeding by tropical herbivores is predicted to expand from the northern Caribbean to extratropical reefs. Conversely, feeding by omnivores is predicted to decrease in this area with minor increases in the Caribbean and southern Brazil. Feeding by invertivores declines across all latitudes in future predictions, jeopardizing a critical trophic link. Most changes are predicted to occur by 2050 and can significantly affect ecosystem functioning, causing dominance shifts and the rise of novel ecosystems.Postprint6,86

Adiabatically changing the phase-space density of a trapped Bose gas

We show that the degeneracy parameter of a trapped Bose gas can be changed adiabatically in a reversible way, both in the Boltzmann regime and in the degenerate Bose regime. We have performed measurements on spin-polarized atomic hydrogen in the Boltzmann regime demonstrating reversible changes of the degeneracy parameter (phase-space density) by more than a factor of two. This result is in perfect agreement with theory. By extending our theoretical analysis to the quantum degenerate regime we predict that, starting close enough to the Bose-Einstein phase transition, one can cross the transition by an adiabatic change of the trap shape.Comment: 4 pages, 3 figures, Latex, submitted to PR

Soil quality and constraints in global rice production

We assessed soil quality in global rice production areas with the Fertility Capability Soil Classification (FCC) system adjusted to match the harmonized world soil database, established by the Food and Agriculture Organization and the International Institute for Applied Systems Analysis. We computed the distribution of 20 soil constraints, and used these to categorize soils as 'good', 'poor', 'very poor', or 'problem soil' for rice production. These data were then combined with data of global rice distribution to determine soil quality in the main rice production systems around the world. Most rice is grown in Asia (143.4. million. ha), followed by Africa (10.5. million. ha) and the Americas (7.2. million. ha). Globally, one-third of the total rice area is grown on very poor soils, which includes 25.6. million. ha of irrigated rice land, 18.5. million. ha in rainfed lowlands, and 7.5. million. ha of upland rice. At least 8.3. million. ha of rice is grown on problem soils, including saline, alkaline/sodic, acid-sulfate, and organic soils. Asia has the largest percentage of rice on good soils (47%) whereas rice production on good soils is much less common in the Americas (28%) and accounts for only 18% in Africa. The most common soil chemical problems in rice fields are very low inherent nutrient status (35.8. million. ha), very low pH (27.1. million. ha), and high P fixation (8.1. million. ha); widespread soil physical problems especially severe in rainfed environments are very shallow soils and low water-holding capacity. The results of the analysis can be used to better target crop improvement research, plant breeding, and the dissemination of stress-specific tolerant varieties and soil management technologies. © 2014 Elsevier B.V.S.M. Haefele, A. Nelson, R.J. Hijman

RehabMove 2018: THE IMPLEMENTATION OF VO2 KINETICS TO EVALUATE TRAINING EFFECTS IN CANCER PATIENTS

PURPOSE: Oxygen uptake (V̇O2) kinetics can be used to measure exercise capacity. A constant work rate (CWR) test at moderate intensity measuring V̇O2 on-kinetics may be more suitable for a deconditioned patient population and a valuable source of information on training effects in addition to the regular exercise tests. The main goal of this study was to compare the sensitivity of V̇O2 on-kinetics during a rest-to-submaximal exercise transition to the regular variables measured in an incremental cardiopulmonary exercise test (CPET): ventilatory threshold (VT), V̇O2peak and peak work rate (WRpeak) to exercise induced changes, and to evaluate the usefulness of V̇O2 on-kinetics in determining an improved exercise capacity with respect to CPET in cancer patients. METHODS: Ten cancer patients (7 females) with a variety of cancer types aged between 39 and 64 years were enrolled in a 12-week rehabilitation program, in which they performed combined cycle-ergometer and strength training for two times a week. At initial and final evaluations, V̇O2 on-kinetics were measured breath-by-breath during a CWR test of moderate intensity, and V̇O2peak and VT were measured with a CPET. RESULTS: Comparisons between pre- and post-intervention showed large effect sizes for V̇O2peak (r = .59) and oxygen uptake at VT (r = .56). V̇O2 on-kinetics did not change after the training program. CONCLUSION: The current results suggest that V̇O2 on-kinetics is not more sensitive to exercise-induced adaptations compared to V̇O2peak and VT. However, V̇O2 on-kinetics did increase in eight of the ten subjects, and can serve as a source of information on training progress, especially when other information is lacking due to a non-maximal CPET or an unreliable VT

Genetic diversity, population structure, and genetic correlation with climatic variation in chickpea (Cicer arietinum) landraces from Pakistan

Chickpea (Cicer arietinum L.) production in arid regions, such as those predominant in Pakistan, faces immense challenges of drought and heat stress. Addressing these challenges is made more difficult by the lack of genetic and phenotypic characterization of available cultivated varieties and breeding materials. Genotyping-by-sequencing offers a rapid and cost-effective means to identify genome-wide nucleotide variation in crop germplasm. When combined with extended crop phenotypes deduced from climatic variation at sites of collection, the data can predict which portions of genetic variation might have roles in climate resilience. Here we use 8113 single nucleotide polymorphism markers to determine genetic variation and compare population structure within a previously uncharacterized collection of 77 landraces and 5 elite cultivars, currently grown in situ on farms throughout the chickpea growing regions of Pakistan. The compiled landraces span a striking aridity gradient into the Thal Desert of the Punjab. Despite low levels of variation across the collection and limited genetic structure, we found some differentiation between accessions from arid, semiarid, irrigated, and coastal areas. In a subset of 232 markers, we found evidence of differentiation along gradients of elevation and isothermality. Our results highlight the utility of exploring large germplasm collections for nucleotide variation associated with environmental extremes, and the use of such data to nominate germplasm accessions with the potential to improve crop drought tolerance and other environmental traits

Spatially explicit species distribution models: A missed opportunity in conservation planning?

Aim: Systematic conservation planning is vital for allocating protected areas given the spatial distribution of conservation features, such as species. Due to incomplete species inventories, species distribution models (SDMs) are often used for predicting species habitat suitability and species probability of occurrence. Currently, SDMs mostly ignore spatial dependencies in species and predictor data. Here, we provide a comparative evaluation of how accounting for spatial dependencies, that is, autocorrelation, affects the delineation of optimized protected areas. Location: Southeast Australia, Southeast U.S. Continental Shelf, Danube River Basin. Methods: We employ Bayesian spatially explicit and non-spatial SDMs for terrestrial, marine and freshwater species, using realm-specific planning unit shapes (grid, hexagon and subcatchment, respectively). We then apply the software gurobi to optimize conservation plans based on species targets derived from spatial and non-spatial SDMs (10% 50% each to analyse sensitivity), and compare the delineation of the plans. Results: Across realms and irrespective of the planning unit shape, spatially explicit SDMs (a) produce on average more accurate predictions in terms of AUC, TSS, sensitivity and specificity, along with a higher species detection probability. All spatial optimizations meet the species conservation targets. Spatial conservation plans that use predictions from spatially explicit SDMs (b) are spatially substantially different compared to those that use non-spatial SDM predictions, but (c) encompass a similar amount of planning units. The overlap in the selection of planning units is smallest for conservation plans based on the lowest targets and vice versa. Main conclusions: Species distribution models are core tools in conservation planning. Not surprisingly, accounting for the spatial characteristics in SDMs has drastic impacts on the delineation of optimized conservation plans. We therefore encourage practitioners to consider spatial dependencies in conservation features to improve the spatial representation of future protected areas. © 2019 The Authors. Diversity and Distributions Published by John Wiley and Sons LtdThis study was funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 642317. SDL has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska‐Curie grant agreement No. 748625, and SCJ from the German Federal Ministry of Education and Research (BMBF) for the “GLANCE” project (Global Change Effects in River Ecosystems; 01 LN1320A). We wish to thank Gwen Iacona and two anonymous referees for their constructive comments on an earlier version of the manuscript

Finite-lattice expansion for Ising models on quasiperiodic tilings

Low-temperature series are calculated for the free energy, magnetisation, susceptibility and field-derivatives of the susceptibility in the Ising model on the quasiperiodic Penrose lattice. The series are computed to order 20 and estimates of the critical exponents alpha, beta and gamma are obtained from Pade approximants.Comment: 16 pages, REVTeX, 26 postscript figure

Claims of Potential Expansion throughout the U.S. by Invasive Python Species Are Contradicted by Ecological Niche Models

BACKGROUND: Recent reports from the United States Geological Survey (USGS) suggested that invasive Burmese pythons in the Everglades may quickly spread into many parts of the U.S. due to putative climatic suitability. Additionally, projected trends of global warming were predicted to significantly increase suitable habitat and promote range expansion by these snakes. However, the ecological limitations of the Burmese python are not known and the possible effects of global warming on the potential expansion of the species are also unclear. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that a predicted continental expansion is unlikely based on the ecology of the organism and the climate of the U.S. Our ecological niche models, which include variables representing climatic extremes as well as averages, indicate that the only suitable habitat in the U.S. for Burmese pythons presently occurs in southern Florida and in extreme southern Texas. Models based on the current distribution of the snake predict suitable habitat in essentially the only region in which the snakes are found in the U.S. Future climate models based on global warming forecasts actually indicate a significant contraction in suitable habitat for Burmese pythons in the U.S. as well as in their native range. CONCLUSIONS/SIGNIFICANCE: The Burmese python is strongly limited to the small area of suitable environmental conditions in the United States it currently inhabits due to the ecological niche preferences of the snake. The ability of the Burmese python to expand further into the U.S. is severely limited by ecological constraints. Global warming is predicted to significantly reduce the area of suitable habitat worldwide, underscoring the potential negative effects of climate change for many species