Absolute Latitude Research Articles

Global patterns and determinants of the initial concentrations of litter carbon components

Plant litter is an important carbon (C) and nutrient pool in terrestrial ecosystems. The C components in plant litter are important because they regulate plant litter decomposition rate, but little is known on the global patterns and determinants of their concentrations in freshly fallen plant litter. Here, we quantified the concentrations of leaf litter C components (i.e., carbohydrate, polyphenol, tannin, and condensed tannin) with 864 measurements from 161 independent publications. We found that (1) the mean concentrations of leaf litter carbohydrate, polyphenol, tannin and condensed tannin were 27.7, 6.08, 8.84 and 5.7 %, respectively; (2) the concentrations of leaf litter C components were affected by taxonomic division, mycorrhizal association, life form, and/or leaf shedding strategy; (3) soil property had similar impacts on the concentrations of the four C compounds, while the influence of mean annual temperature and precipitation varied; and (4) elevation had opposing effects on carbohydrate and polyphenol concentrations, but not on that of tannin and condensed tannin, and only carbohydrate concentration was strongly affected by absolute latitude. In general, our results clearly show the global patterns and drivers of the concentrations of litter C compounds, providing new insights into the role of litter decomposition in global C dynamics.

Mycorrhizal fungi modify decomposition: a meta-analysis.

It has been proposed that ectomycorrhizal fungi can reduce decomposition while arbuscular mycorrhizal fungi may enhance it. These phenomena are known as the 'Gadgil effect' and 'priming effect', respectively. However, it is unclear which one predominates globally. We evaluated whether mycorrhizal fungi decrease or increase decomposition, and identified conditions that mediate this effect. We obtained decomposition data from 43 studies (97 trials) conducted in field or laboratory settings that controlled the access of mycorrhizal fungi to substrates colonized by saprotrophs. Across studies, mycorrhizal fungi promoted decomposition of different substrates by 6.7% overall by favoring the priming effect over the Gadgil effect. However, we observed significant variation among studies. The substrate C : N ratio and absolute latitude influenced the effect of mycorrhizal fungi on decomposition and contributed to the variation. Specifically, mycorrhizal fungi increased decomposition at low substrate C : N and absolute latitude, but there was no discernable effect at high values. Unexpectedly, the effect of mycorrhizal fungi was not influenced by the mycorrhizal type. Our findings challenge previous assumptions about the universality of the Gadgil effect but highlight the potential of mycorrhizal fungi to negatively influence soil carbon storage by promoting the priming effect.

The macroevolution of sexual size dimorphism in birds

Abstract There is considerable variation of sexual size dimorphism (SSD) in body mass among animal groups, yet the drivers of interspecific variation in SSD are still poorly understood. Possible mechanisms have been suggested, including sexual selection, selection for fecundity in females, niche divergence between sexes, and allometry, yet their relative importance is still poorly understood. Here, we tested predictions of these four hypotheses in different avian groups using a large-scale dataset on SSD of body mass for 4761 species. Specifically, we estimated the probability of transition between male- and female-biased SSD, tested for differences in evolutionary rates of body mass evolution for males and females, and assessed the potential ecological and spatial correlates of SSD. Our results were consistent with the sexual selection, fecundity, and niche divergence hypotheses, but their support varied considerably among avian orders. In addition, we found little evidence that the direction of SSD affected the evolution of male or female body mass, and no relationship was detected between SSD and environmental predictors (i.e. temperature and precipitation seasonality, productivity, species richness, and absolute latitude). These results suggest that avian evolution of SSD is likely to be multifactorial, with sexual selection, fecundity, and niche divergence playing important roles in different avian orders.

Fundamentals of Institutional Quality and Economic Freedom

ABSTRACT: Social scientists have extensively studied the causes of good institutions, including the origins of economic freedom. Results concerning the causes of different kinds of institutions are often similar, often concluding that the geography, environment, and culture are important factors. However, a recent political economy framework suggests that certain dimensions of economic freedom, namely specific dimensions of the size of government (government consumption, transfers and subsidies, and the top marginal tax rate), differ systematically from other dimensions of liberalization. This paper explores these arguments by constructing an index of a set of consensus predictors of institutional quality: ethnic fractionalization (predicts negatively), the natural log of the population size (negatively), absolute latitude (positively), natural resource rents (negatively), the presence of the country in the Americas (negatively), British legal origins (positively), the presence of the country in Eurasia (positively), and island geography (positively). The countries with the “best” fundamentals for institutional quality are Iceland, Ireland, Malta, Finland, and Cyprus, while the five with the “worst” fundamentals are Angola, Nigeria, Chad, Burkina Faso, and Ghana. It then takes this index of “fundamentals” of institutional quality and shows that, although they predict economic liberalism as a whole (as measured by the Economic Freedom of the World index) as they would predict other measures of institutional quality, they predict oppositely (i.e., corresponding to larger governments) for the dimensions of the size of government listed above. The result is congruent with the predictions of the political economy model. Additionally, this result is not contingent on the inclusion of any one of the “fundamental” variables, although natural resource rents and absolute latitude appear to be the most important variables. Countries with considerably more economic freedom than would be predicted by their fundaments include Peru, Singapore, the United States, Chile, and Canada; should deviations from fitted values be seen as presaging future movements in institutions, these countries are the most likely to see upcoming declines. The aforementioned political economy model implies that these findings are the result of complexities involved in the interaction between state capacity and different dimensions of economic liberalization.

Effects of temperature on growth, development, and survival of amphibian larvae: macroecological and evolutionary patterns.

Temperature affects the rate of biochemical and physiological processes in amphibians, influencing metamorphic traits. Temperature patterns, as those observed in latitudinal and altitudinal clines, may impose different challenges on amphibians depending on how species are geographically distributed. Moreover, species' response to environmental temperatures may also be phylogenetically constrained. Here, we explore the effects of acclimation to higher temperatures on tadpole survival, development, and growth, using a meta-analytical approach. We also evaluate whether the latitude and climatic variables at each collection site can explain differences in species' response to increasing temperature and whether these responses are phylogenetically conserved. Our results show that species that develop at relatively higher temperatures reach metamorphosis faster. Furthermore, absolute latitude at each collection site may partially explain heterogeneity in larval growth rate. Phylogenetic signal of traits in response to temperature indicates a non-random process in which related species resemble each other less than expected under Brownian motion evolution (BM) in all traits, except survival. The integration of studies in a meta-analytic framework allowed us to explore macroecological and macroevolutionary patterns and provided a better understanding of the effects of climate change on amphibians.

Differential Rotation for Different-sized Sunspot Groups Early Observed by the OGAUC

Solar differential rotation is an important ingredient of the solar dynamo model, not only because the solar rotation profile is one of the key inputs in a solar dynamo model, but also because it imposes constraints for the solar dynamo model. In this study, we use the sunspot group catalog published by the Coimbra Astronomical Observatory for the period 1929–1941 to analyze solar rotation profiles of different-sized sunspot groups and the dependence of their annual average of the absolute latitude and annual average rotation rate on the solar cycle. The following main results are obtained: (1) smaller sunspot groups (with an area <100 millionths of the solar hemisphere (msh)) rotate faster than larger ones (with an area >500 msh); (2) different-sized sunspot groups drift toward the equator at different velocities of latitudinal drift, reflecting that they are rooted at different anchoring depths; (3) the rotation rate reaches a maximum during the minimum of the solar cycle, which seems to be independent of the size of sunspot groups. The possible mechanisms for the above results are discussed, and we infer that the differences may be due to the different anchoring depths at which flux tubes of different-sized sunspot groups are rooted, their different ages, and the different ways in which sunspot group coordinates are determined.

Global patterns and drivers of lead concentration in inland waters

Water bodies are important carriers for lead (Pb) biogeochemical cycling, which is a key pathway of Pb transport. Although existing studies on Pb loading in inland waters have developed rapidly, a quantitative assessment of the distribution patterns and drivers of Pb concentration in inland waters at the global scale remains unclear. Here, by analyzing 1790 observations collected from 386 independent publications, we assessed the spatial distribution and drivers of Pb concentration in inland waters worldwide. We found that (1) globally, the median of Pb concentration in inland waters was 5.81 μg L−1; (2) among different inland water types, Pb concentration was higher in rivers, and the highest Pb concentration was in industrial land in terms of land use type; (3) Pb concentration in inland waters were positively driven by potential evapotranspiration, elevation and road density; and (4) Pb concentration showed a negative relationship with absolute latitude, decreasing from tropic to boreal regions. Overall, our global assessment of the patterns and drivers of Pb concentration in inland waters contributed to a better understanding of the natural and anthropogenic attributions of Pb in the inland hydrological cycling.

Circadian gene variation in relation to breeding season and latitude in allochronic populations of two pelagic seabird species complexes

Annual cues in the environment result in physiological changes that allow organisms to time reproduction during periods of optimal resource availability. Understanding how circadian rhythm genes sense these environmental cues and stimulate the appropriate physiological changes in response is important for determining the adaptability of species, especially in the advent of changing climate. A first step involves characterizing the environmental correlates of natural variation in these genes. Band-rumped and Leach’s storm-petrels (Hydrobates spp.) are pelagic seabirds that breed across a wide range of latitudes. Importantly, some populations have undergone allochronic divergence, in which sympatric populations use the same breeding sites at different times of year. We investigated the relationship between variation in key functional regions of four genes that play an integral role in the cellular clock mechanism—Clock, Bmal1, Cry2 and Per2—with both breeding season and absolute latitude in these two species complexes. We discovered that allele frequencies in two genes, Clock and Bmal1, differed between seasonal populations in one archipelago, and also correlated with absolute latitude of breeding colonies. These results indicate that variation in these circadian rhythm genes may be involved in allochronic speciation, as well as adaptation to photoperiod at breeding locations.

Patterns of functional diversity along latitudinal gradients of species richness in eleven fish families

AbstractAimAs we enter an era of major biodiversity shifts, understanding large‐scale biodiversity patterns has become crucial for ecological and conservation purposes. Often, conservation priorities are based on concepts derived largely from species richness, yet recent work shows that different facets of biodiversity are also crucial for proper ecosystem continuity, function and services. One facet of biodiversity increasingly relevant to conservation is functional diversity. Here, we aim to improve our understanding of large‐scale patterns of biodiversity by testing the hypothesis that species richness can also accurately estimate functional diversity along the latitudinal gradient of species richness in fish.LocationMarine environments.Time periodContemporary.Major taxa studiedEight hundred and forty‐two species within 11 fish families: Acanthuridae, Blenniidae, Chaetodontidae, Gobiidae, Labridae, Lutjanidae, Pleuronectidae, Pomacanthidae, Pomacentridae, Scombridae and Sparidae.MethodsUsing geometric morphometrics to calculate morphological diversity, a proxy for functional diversity, we estimated the expected functional diversity for a given number of species and compared it with the observed functional diversity in fish families along latitudes. We then fitted a broken‐stick regression model with estimates of functional diversity over absolute degree of latitudes to locate latitudes where significant shifts in functional diversity occur.ResultsWe found that species richness typically over‐ or underestimated functional diversity along the latitudinal gradient of species richness in the evaluated fishes. We also showed that for most families investigated, there was a pattern of stable functional diversity from the equator through the tropics that shifted, with a mean inflection point occurring at absolute latitude 31.7 ± 10.1°. We suggest that this pattern might be linked to changes in environmental factors such as global temperature and/or habitat availability beyond tropical latitudes; however, these concepts require more study.Main conclusionsThis analysis shows the importance of considering functional diversity further, in combination with other biodiversity metrics, when developing conservation priorities and policies.

Does aerobic scope influence geographical distribution of teleost fishes?

Many abiotic and biotic factors are known to shape species' distributions, but we lack understanding of how innate physiological traits, such as aerobic scope (AS), may influence the latitudinal range of species. Based on theoretical assumptions, a positive link between AS and distribution range has been proposed, but there has been no broad comparative study across species to test this hypothesis. We collected metabolic rate data from the literature and performed a phylogenetically informed analysis to investigate the influence of AS on the current geographical distributions of 111 teleost fish species. Contrary to expectations, we found a negative relationship between absolute latitude range and thermal peak AS in temperate fishes. We found no evidence for an association between thermal range of AS and the range of latitudes occupied for 32 species. Our main results therefore contradict the prevailing theory of a positive link between AS and distribution range in fish.

Vulnerability to climate change increases with trophic level in terrestrial organisms

The resilience of ecosystem function under global climate change is governed by individual species vulnerabilities and the functional groups they contribute to (e.g. decomposition, primary production, pollination, primary, secondary and tertiary consumption). Yet it remains unclear whether species that contribute to different functional groups, which underpin ecosystem function, differ in their vulnerability to climate change. We used existing upper thermal limit data across a range of terrestrial species (N = 1701) to calculate species warming margins (degrees distance between a species upper thermal limit and the maximum environmental temperature they inhabit), as a metric of climate change vulnerability. We examined whether species that comprise different functional groups exhibit differential vulnerability to climate change, and if vulnerability trends change across geographic space while considering evolutionary history. Primary producers had the broadest warming margins across the globe (μ = 18.72 °C) and tertiary consumers had the narrowest warming margins (μ = 9.64 °C), where vulnerability tended to increase with trophic level. Warming margins had a nonlinear relationship (second-degree polynomial) with absolute latitude, where warming margins were narrowest at about 33°, and were broader at lower and higher absolute latitudes. Evolutionary history explained significant variation in species warming margins, as did the methodology used to estimate species upper thermal limits. We investigated if variation in body mass across the trophic levels could explain why higher trophic level organisms had narrower warming margins than lower trophic level organisms, however, we did not find support for this hypothesis. This study provides a critical first step in linking individual species vulnerabilities with whole ecosystem responses to climate change.

Population, economic and geographic predictors of nations' medal tallies at the Pyeongchang and Tokyo Olympics and Paralympics.

PurposeRanking of nations by medal tally is a popular feature of the Olympics, but such ranking is a poor measure of sporting prowess or engagement until the tallies are adjusted for major factors beyond the control of individual nations. Here we estimate and adjust for effects of total population, economy expressed as gross domestic product per capita, absolute latitude and Muslim population proportion on total medal counts in female, male, mixed and all events at the Pyeongchang winter and Tokyo summer Olympics and Paralympics.MethodsThe statistical model was multiple linear over-dispersed Poisson regression. Population and economy were log-transformed; their linear effects were expressed in percent per percent units and evaluated in magnitude as the factor effects of two between-nation standard deviations (SD). The linear effect of absolute latitude was expressed and evaluated as the factor effect of 30° (approximately 2 SD). The linear effect of Muslim proportion was expressed as the factor effect of 100% vs. 0% Muslim. Nations were ranked on the basis of actual vs. predicted all-events medal counts.ResultsAt the Pyeongchang Olympics, effects of population and economy were 0.7–0.8 %/% and 1.1–1.7 %/% (welldefined extremely large increases for 2 SD), factor effects of 30° of latitude were 11–17 (welldefined extremely large increases), and factor effects of 100% Muslim population were 0.08–0.69 (extremely large to moderate reductions, albeit indecisive). Effects at the Tokyo Olympics were similar in magnitude, including those of latitude, which were surprisingly still positive although diminished (large to very large increases). Effects at the Pyeongchang and Tokyo Paralympics were generally similar to those at the Olympics, but the effects of economy were diminished (large to very large increases). After adjustment of medal tallies for these effects, nations that reached the top-10 medalists in both winter games were Austria, Belarus, Kazakhstan, Slovakia and Ukraine, but only Azerbaijan reached the top-10 in both summer games.ConclusionAdjusting medal counts for demographic and geographic factors provides a comparison of nations' sporting prowess or engagement that is more in keeping with the Olympic ideal of fair play and more useful for nations' Olympic-funding decisions.

Individualism Versus Collectivism and the Early-Stage Transmission of COVID-19.

We propose a perspective based on the individualism versus collectivism (IC) cultural distinction to understand the diverging early-stage transmission outcomes of COVID-19 between countries. Since individualism values personal freedom, people in such cultures would be less likely to make the collective action of staying at home and less likely to support compulsory measures. As a reaction to the public will, governments of individualistic societies would be more hesitant to take compulsory measures, leading to the delay of necessary responses. With processed COVID-19 data that can provide a fair comparison, we find that COVID-19 spread much faster in more individualistic societies than in more collectivistic societies. We further use pronoun drop and absolute latitude as the instruments for IC to address reverse causality and omitted variable bias. The results are robust to different measures. We propose to consider the role of IC not only for understanding the current pandemic but also for thinking about future trends in the world.

Urbanisation dampens the latitude‐diversity cline in ants

Abstract The increase in species diversity from temperate to tropical regions is one of the most widespread patterns in biogeography. As humans continue to drastically modify natural habitats, land‐use changes such as the development of cities could potentially alter typical latitudinal diversity gradients. Cities could depress or enhance biodiversity through filtering, localised extirpations, or increasing niche availability, respectively. To address these possibilities and the consequences for the latitudinal diversity gradient, we constructed a global dataset of urban species diversity (richness) and community composition across ~60° of absolute latitude and from 63 cities. We focused our study on ants, for which comparable urban and non‐urban diversity data are broadly available. We found that urbanisation significantly dampened the latitude‐diversity cline. The effects of urbanisation varied with latitude: at lower latitudes, cities were relatively species poor and harboured distinct ant communities relative to nearby non‐urban communities. In higher latitude cities, both species richness and community composition were more similar to the surrounding non‐urban ant communities. Our analyses suggest that the strongest impacts of urbanisation on ant diversity may be in the tropics, where biological diversity is already expected to experience the greatest risk of extinction in the face of climate change.

Composition and Biogeography of Planktonic Pro- and Eukaryotic Communities in the Atlantic Ocean: Primer Choice Matters.

Basin-scale biogeographic observations of marine pelagic pro- and eukaryotic communities are necessary to understand forces driving community composition and for providing a baseline to monitor global change. Deep sequencing of rRNA genes provides community composition at high resolution; yet, it is unclear how the choice of primers affects biogeographic patterns. Here, we re-amplified 16S rRNA genes from DNA sampled during R/V Polarstern Cruise ANT28-5 over a latitudinal transect across the Atlantic Ocean from 52°S to 47°N using universal V4-V5 primers and compared the results with those obtained previously with V5-V6 bacteria-specific primers. For validation of our results, we inferred community composition based on 16S rRNA genes of metagenomes from the same stations and single amplified genomes (SAGs) from the Global Ocean Reference Genome (GORG) database. We found that the universal V4-V5 primers retrieved SAR11 clades with similar relative proportions as those found in the GORG database while the V5-V6 primers recovered strongly diverging clade abundances. We confirmed an inverse bell-shaped distance-decay relationship and a latitudinal diversity gradient that did not decline linearly with absolute latitude in the Atlantic Ocean. Patterns were modified by sampling depth, sequencing depth, choice of primers, and abundance filtering. Especially richness patterns were not robust to methodological change. This study offers a detailed picture of the Atlantic Ocean microbiome using a universal set of PCR primers that allow for the conjunction of biogeographical patterns among organisms from different domains of life.

Global variation in early epidemic growth rates and reproduction number of seasonal influenza

BackgroundLittle is known about global variation in early epidemic growth rates and effective reproduction numbers (Re) of seasonal influenza. We aimed to estimate global variation in Re of influenza type A and B during a single period. MethodsCountry influenza detection time series from September 2017 through January 2019 were obtained from an international database. Type A and B epidemics by country were selected on the basis of Re estimates for a five-week moving window, advanced by week. Associations of Re with absolute latitude, human development index, percent of the population aged <15 years, and percent of those living in rural areas in each country were assessed. ResultsTime series were included for 119 of 169 available countries. There were 100 countries with influenza A and 79 with B epidemics. Median Re for both influenza A and B epidemics was 1.23 (ranges: A 1.10, 1.60; B 1.06, 1.58). Re of influenza B but not A was independently associated with absolute latitude, increasing by 0.022 (95% confidence interval 0.002, 0.043) per 10 degrees. ConclusionThe Re of influenza A and B were similar. Only the Re of influenza B was associated with country characteristics, which was increasing with distance from the equator. The approach may be suitable for continuous Re surveillance.

Corrigendum

Corrigendum

Direct conversion of latitude and height from one ellipsoid to another

I suggest a method for converting geodetic height and latitude from one oblate ellipsoid of revolution to another having the same center and symmetry axis. Unlike other approaches, the method here does not obtain height and latitude from Earth-centered, Earth-fixed (ECEF) Cartesian coordinates; this feature allows height conversion with high accuracy even in cases where the data format limits the precision of the latitude data. Height and latitude conversions can be expressed as a Fourier series in even multiples of latitude, with height changes having only cosines and latitude changes having only sines. The absolute difference of the flattenings of the two ellipsoids furnishes a simple upper bound on the maximum absolute latitude change. Conversions between the TOPEX and WGS84 ellipsoids, a practical necessity for the inter-mission comparison of satellite laser and radar altimeter data, illustrate the findings. Because the differences in the flattenings and semi-major axes of these ellipsoids are small, truncating the Fourier series after the term in twice the latitude gives an approximate conversion with an error less than 9 times 10–12 radians of latitude and about 6 times 10–6 m of height.

Tilt correction to maximize energy yield from bifacial PV modules

The ability of bifacial photovoltaic (PV) modules to generate additional energy from the rear side makes the selection of a tilt angle more challenging than its counterpart monofacial PV. Multiple factors such as site conditions (albedo, average sun-hour ambient temperature, elevation from sea level, diffuse fraction, global horizontal irradiance, and latitude) and PV module specifications (such as bifaciality, power temperature coefficient, and efficiency) can influence the optimum tilt that ensures maximum annual yield of the bifacial PV modules. System Advisor Model (SAM) is used to generate a training dataset of optimal tilt that covers a global range of site conditions and module specifications. Furthermore, we used a Ranker-based feature selection approach to evaluate features and generate a rank-list based on their R-squared score to the dependent variable. From all the available features, the absolute latitude value, sun hour ambient temperature, global horizontal irradiance, and albedo are the most significant features. The best results offer a mathematical model to predict the optimum tilt with the lowest RMSE of 2.135° and an R2 of 0.96 given 8 site and module features.

UV Radiation, not European Ancestry, Explains States’ Cognitive Performance in Brazil and USA

A debate in Mankind Quarterly positing racial categorization of populations vis-à-vis biological effects of UV radiation was based on data from a single country, used absolute latitude instead of UV radiation, and limited the analysis to path analysis. To overcome limitations of the studies, we utilized measurements of UV radiation for 26 Brazilian and 48 USA states instead of absolute latitude and performed seemingly unrelated regressions in addition to path analysis. NAEP scores and infectious disease rate were collected in USA and PISA scores and infant mortality in Brazil. Significant cognitive effects of European ancestry were replicated, but showed spuriousness, disappearing when the effects of UV radiation were controlled. Our evidence strongly suggests that UV radiation is a consistent antecedent of cognitive ability directly and through income in the USA and Brazil and through infant mortality in Brazil, whereas European ancestry only influences cognitive ability positively by reducing infectious diseases in the USA or infant mortality in Brazil. The between-country consistency of our findings compensates for methodological weaknesses that took place especially in the Brazil study. Psychologists and economists should be aware of these findings to avoid making erroneous inferences based on genetic or cultural variables.