Search

Motivation for abandoning the 'environmental filtering' metaphor has been increasing in the literature, yet it remains a widely used conceptual tool to guide research and education within ecological disciplines. I consider the possible origins of the filtering paradigm through linkages to hypotheses about the potentially oversized role of localized competition in the early development of niche concepts, as well as assumptions about the scale dependence of factors influencing the species distributions at large scales. I believe that these perspectives may have discounted the relevance of non‐competitive interactions to the structure and maintenance of local communities, and the role of biotic interactions in large‐scale ecological processes more generally. I describe the types of ecological phenomena not readily captured by the filtering model, as well as the potential for biotic factors to interact with abiotic gradients (at scale) and influence broad ecological patterns. Lastly, I pose an alternative model of community assembly which emphasizes biotic–abiotic interactions and non‐filtering mechanisms to serve as a springboard for future renovations of the filtering metaphor. [ABSTRACT FROM AUTHOR]

The constraint of computational power and the huge number of degrees of freedom of the atmosphere means a sampling uncertainty exists in probabilistic ensemble forecasts. In our previous study, the uncertainty could be quantified, creating a convergence measure which converges proportional to n−1/2 in the limit of large ensemble size n. This power law can then be extrapolated to determine how sampling uncertainty would decrease with larger ensemble sizes and hence find the necessary ensemble size. It is unknown, however, how the sampling uncertainty depends on different weather regimes. This study extends the previous idealised ensemble developed, by including weak and strong forcing convective weather regimes, to look at how sampling uncertainty convergence differs in each. Two 5,000‐member ensembles were run, with weak and strong forcing respectively. Comparisons with a kilometre‐scale weather prediction model ensured realistic weak and strong forcing regimes by comparing the rain, convective available potential energy (CAPE), convective adjustment timescale, and distribution shapes throughout the diurnal cycle. Differences in distribution shape between the regimes led to differences in the convergence measure. Large differences in spread between weak and strong forcing runs throughout the 24 hr period led to large differences in sampling uncertainty of the mean and standard deviation, which could be quantified according to well‐known equations. The timing of these differences was case‐dependent. For extreme statistics such as the 0.95 quantile and for cases where there was precipitation, the moisture variables for the weak forcing case had the largest sampling uncertainty and required the most members for convergence proportional to n−1/2. This was due to the tails of the weak forcing moisture variables containing the least amount of density. Different ensemble sizes will hence be required depending on whether one is in the weak or strong forcing convective weather regime. [ABSTRACT FROM AUTHOR]

Damaging aftershock sequences often exhibit considerable spatio‐temporal complexity. The stress changes associated with coseismic slip and aseismic afterslip are commonly proposed to drive aftershock sequences, but few systematic studies exist and do not always support strong, universal driving relationships. To investigate the roles that these two sources of stress changes may play in driving aftershocks, we assess the spatio‐temporal relationships between coseismic slip, afterslip, and on‐fault (within 5 km) aftershock density following seven Mw6.0–7.6 continental‐settings earthquakes, using available high‐quality slip models and regional seismic data. From previous empirical work and frictional considerations, near the mainshock we expect coseismic slip and afterslip to be anti‐correlated, and aftershocks to occur where coseismic slip is low/zero, near high slip gradients, and/or to migrate with afterslip. However, we find that spatial relationships between afterslip and coseismic slip, and between afterslip and aftershock density differ between earthquakes. Aftershock density correlates with coseismic slip following five of the earthquakes, and with total cumulative slip (coseismic slip + afterslip) following six: indicating that on‐fault aftershock distributions may be approximated by total slip (at current resolutions). Additionally, we find that the gradients of coseismic slip and afterslip (proxies for new stress concentrations) do not clearly correlate with aftershock distributions and that the choice of spatial domain over which relationships are tested can affect results significantly. A possible explanation of these results is that fault zones contain considerable fine‐scale structural and frictional heterogeneity. Nonetheless, the empirical evidence for frequently assumed relationships between coseismic slip, afterslip and on‐fault aftershocks is mixed. Plain Language Summary: The spatial distributions of aftershocks following major earthquakes can be complex and varied. We investigate how the locations of aftershocks on the main fault relate to the distributions of slip from the mainshock itself and from a gentle relaxation process that occurs on the fault in the following weeks, months, and years, called afterslip: we expect aftershocks to broadly occur where afterslip is and where mainshock slip is low/zero. We investigate seven interesting mainshocks that occur within comparable continental settings and show that spatial relationships between coseismic slip, afterslip, and aftershocks vary between these case studies. Aftershocks generally occur where slip of some kind (either mainshock slip or afterslip) has been modeled, which may be useful for estimating the broad distribution of on‐fault aftershocks in the future. As mainshock slip, afterslip, and aftershocks often appear to be occurring in exactly the same regions (contradicting common assumptions), we propose that fault zones contain finer scale detail than can currently be resolved. Key Points: We explore how coseismic slip and afterslip distributions may influence on‐fault aftershock density following seven key continental earthquakesTotal modeled slip often correlates well with on‐fault aftershock density thus could be used as an indicator of aftershock evolutionCoseismic slip, afterslip, and aftershocks commonly co‐locate, contrary to expectations, possibly due to unresolved slip heterogeneity [ABSTRACT FROM AUTHOR]

Sulfides with different distribution states may have different effects on steel properties. How to separately count each kind of sulfide remains a question. In the current study, sulfides in 1215 free‐cutting and 416 free‐cutting stainless steel are counted by Image‐Pro Plus image‐processing software. The sulfides can be divided into three categories, that is, cluster‐like sulfides, chain‐like sulfides, and individual sulfides. The features of each kind of sulfide are summarized and an automatic sulfide classification method is proposed. By using this method, sulfides in a metallographic photograph of 1215 steel are successfully classified into three types and counted separately. The quantity percentage of chain‐like, cluster‐like, and individual sulfides is 24.65%, 56.79%, and 18.56%, respectively, while the area percentage of different types of sulfides is 34.33%, 52.80%, and 12.87%. Individual sulfides have the highest‐quantity percentage of sulfides with a diameter smaller than 3 μm and with an area smaller than 10 μm2. Through this method, different types of sulfides can be deeply analyzed. It offers reliable data to evaluate whether the sulfides are well controlled or not, providing a guideline for the improvement of sulfide control methods. [ABSTRACT FROM AUTHOR]

Summary: A refinement of a previous asymptotic analysis of the well‐known two‐capacitor circuit is presented. It rests on some mathematical results, which allow the originally conceived regularity constraint to be replaced with a new one, not only less restrictive but also and above all simpler and easier to check. On this basis, the main time domain diagrams of the circuit with the embedding switch are presented. In addition, the solution of the circuit in the transition interval is provided, and some calculations related to the distribution side of the analysis are also reconsidered and improved. [ABSTRACT FROM AUTHOR]

This article is the Editorial for the Special Collection 'Global plant diversity and distribution'. See https://www.newphytologist.org/global-plant-diversity for more details. [ABSTRACT FROM AUTHOR]

Species' distributions are moving polewards in response to climate change, and although range expansions of relatively warm‐adapted species are widely reported, reports of range retractions in cool‐adapted species are less common. Here, we analysed species' distribution shifts for 76 cool‐adapted moths in Great Britain using citizen science occurrence records from the National Moth Recording Scheme over a 40‐year period. Although we find evidence for trailing edge shifts to higher latitudes, shifts in species' range centroids are oriented towards the north‐west, and are more closely correlated with directional changes in total precipitation than average temperature. We also found that species' local extinction risk is higher in areas where temperature is high and precipitation is low, but this risk diminishes as precipitation increases. Adaptation efforts should therefore focus on maintaining or increasing water availability as the climate continues to change. [ABSTRACT FROM AUTHOR]

Many operational weather services use ensembles of forecasts to generate probabilistic predictions. Computational costs generally limit the size of the ensemble to fewer than 100 members, although the large number of degrees of freedom in the forecast model would suggest that a vastly larger ensemble would be required to represent the forecast probability distribution accurately. In this study, we use a computationally efficient idealised model that replicates key properties of the dynamics and statistics of cumulus convection to identify how the sampling uncertainty of statistical quantities converges with ensemble size. Convergence is quantified by computing the width of the 95% confidence interval of the sampling distribution of random variables, using bootstrapping on the ensemble distributions at individual time and grid points. Using ensemble sizes of up to 100,000 members, it was found that for all computed distribution properties, including mean, variance, skew, kurtosis, and several quantiles, the sampling uncertainty scaled as n−1/2 for sufficiently large ensemble size n. This behaviour is expected from the Central Limit Theorem, which further predicts that the magnitude of the uncertainty depends on the distribution shape, with a large uncertainty for statistics that depend on rare events. This prediction was also confirmed, with the additional observation that such statistics also required larger ensemble sizes before entering the asymptotic regime. By considering two methods for evaluating asymptotic behaviour in small ensembles, we show that the large‐n theory can be applied usefully for some forecast quantities even for the ensemble sizes in operational use today. [ABSTRACT FROM AUTHOR]

Global climate change is increasing the frequency and severity of extreme climatic events (ECEs) which may be especially detrimental during late‐winter when many species are surviving on scarce resources. However, monitoring animal populations relative to ECEs is logistically challenging. Crowd‐sourced datasets may provide opportunity to monitor species' responses to short‐term chance phenomena such as ECEs. We used 14 years of eBird—a global citizen science initiative—to examine distribution changes for seven wintering waterfowl species across North America in response to recent extreme winter polar vortex disruptions. To validate inferences from eBird, we compared eBird distribution changes against locational data from 362 GPS‐tagged Mallards (Anas platyrhynchos) in the Mississippi Flyway. Distributional shifts between eBird and GPS‐tagged Mallards were similar following an ECE in February 2021. In general, the ECE affected continental waterfowl population distributions; however, responses were variable across species and flyways. Waterfowl distributions tended to stay near wintering latitudes or moved north at lesser distances compared with non‐ECE years, suggesting preparedness for spring migration was a stronger "pull" than extreme weather was a "push" pressure. Surprisingly, larger‐bodied waterfowl with grubbing foraging strategies (i.e., geese) delayed their northward range shift during ECE years, whereas smaller‐bodied ducks were less affected. Lastly, wetland obligate species shifted southward during ECE years. Collectively, these results suggest specialized foraging strategies likely related to resource limitations, but not body size, necessitate movement from extreme late‐winter weather in waterfowl. Our results demonstrate eBird's potential to monitor population‐level effects of weather events, especially severe ECEs. eBird and other crowd‐sourced datasets can be valuable to identify species which are adaptable or vulnerable to ECEs and thus, begin to inform conservation policy and management to combat negative effects of global climate change. [ABSTRACT FROM AUTHOR]

Human activities alter ecosystems everywhere, causing rapid biodiversity loss and biotic homogenization. These losses necessitate coordinated conservation actions guided by biodiversity and species distribution spatial data that cover large areas yet have fine‐enough resolution to be management‐relevant (i.e., ≤5 km). However, most biodiversity products are too coarse for management or are only available for small areas. Furthermore, many maps generated for biodiversity assessment and conservation do not explicitly quantify the inherent tradeoff between resolution and accuracy when predicting biodiversity patterns. Our goals were to generate predictive models of overall breeding bird species richness and species richness of different guilds based on nine functional or life‐history‐based traits across the conterminous United States at three resolutions (0.5, 2.5, and 5 km) and quantify the tradeoff between resolution and accuracy and, hence, relevance for management of the resulting biodiversity maps. We summarized 18 years of North American Breeding Bird Survey data (1992–2019) and modeled species richness using random forests, including 66 predictor variables (describing climate, vegetation, geomorphology, and anthropogenic conditions), 20 of which we newly derived. Among the three spatial resolutions, the percentage variance explained ranged from 27% to 60% (median = 54%; mean = 57%) for overall species richness and 12% to 87% (median = 61%; mean = 58%) for our different guilds. Overall species richness and guild‐specific species richness were best explained at 5‐km resolution using ~24 predictor variables based on percentage variance explained, symmetric mean absolute percentage error, and root mean square error values. However, our 2.5‐km‐resolution maps were almost as accurate and provided more spatially detailed information, which is why we recommend them for most management applications. Our results represent the first consistent, occurrence‐based, and nationwide maps of breeding bird richness with a thorough accuracy assessment that are also spatially detailed enough to inform local management decisions. More broadly, our findings highlight the importance of explicitly considering tradeoffs between resolution and accuracy to create management‐relevant biodiversity products for large areas. [ABSTRACT FROM AUTHOR]

Frameworks for deriving occupational exposure limits (OELs) and OEL‐analogue values (such as derived‐no‐effect levels [DNELs]) in various regulatory areas in the EU and at national level in Germany were analysed. Reasons for differences between frameworks and possible means of improving transparency and harmonisation were identified. Differences between assessment factors used for deriving exposure limits proved to be one important reason for diverging numerical values. Distributions for exposure time, interspecies and intraspecies extrapolation were combined by probabilistic methods and compared with default values of assessment factors used in the various OEL frameworks in order to investigate protection levels. In a subchronic inhalation study showing local effects in the respiratory tract, the probability that assessment factors were sufficiently high to protect 99% and 95% of the target population (workers) from adverse effects varied considerably from 9% to 71% and 17% to 87%, respectively, between the frameworks. All steps of the derivation process, including the uncertainty associated with the point of departure (POD), were further analysed with two examples of full probabilistic assessments. It is proposed that benchmark modelling should be the method of choice for deriving PODs and that all OEL frameworks should provide detailed guidance documents and clearly define their protection goals by stating the proportion of the exposed population the OEL aims to cover and the probability with which they intend to provide protection from adverse effects. Harmonisation can be achieved by agreeing on the way to perform the methodological steps for deriving OELs and on common protection goals. The frameworks for deriving occupational exposure limits (OELs) and OEL‐analogue values (such as derived‐no‐effect levels [DNELs]) in various regulatory areas in the EU and at the national level in Germany were analysed. Distributions for exposure time, interspecies and intraspecies extrapolation were combined by probabilistic methods and compared with assessment factors used in the various OEL frameworks in order to investigate protection levels. [ABSTRACT FROM AUTHOR]

This work aimed at improving the empirical database of time (i.e., exposure duration), interspecies and intraspecies extrapolation when deriving occupational exposure limits (OELs). For each extrapolation step, a distribution was derived, which can be used to model the associated uncertainties. For time and interspecies extrapolation, distributions of ratios of dose descriptors were derived from studies of different length or species. National Toxicology Program (NTP) study data were manually assessed, and data from REACH (Registration, Evaluation and Authorisation of Chemicals) registration dossiers were evaluated semi‐automatically. Intraspecies extrapolation was investigated by compiling published studies on human toxicokinetic and toxicodynamic variability. A new database was established for toxicokinetic differences in interindividual susceptibility, including many inhalation studies. Using NTP data produced more reliable results than using REACH data. The geometric mean (GM) for time extrapolation subacute/chronic agreed with previous evaluations (GM = 4.11), whereas the GM for subchronic/chronic extrapolation was slightly higher (GM = 2.93) than the GMs found by others. No significant differences were observed between systemically and locally acting substances. Observed interspecies differences confirmed the suitability of allometric scaling, with the derived distribution describing remaining uncertainty. Distributions of intraspecies variability at the 1% and 5% incidence level had medians of 7.25 and 3.56, respectively. When compared with assessment factors (AFs) currently used in the EU, probabilities that these AFs are protective enough span a wide range from 10% to 95%, depending on the extrapolation step. These results help to select AFs in a transparent and informed way and, by allowing to compare protection levels achieved, to harmonise methods for deriving OELs. This work aimed at improving the empirical database of time (i.e., exposure duration), interspecies and intraspecies extrapolation. Distributions were derived, which can be used to model the associated uncertainties. When compared with assessment factors (AFs) currently used in the EU, probabilities that these AFs are protective enough span a wide range from 10% to 95%, depending on the extrapolation step. These results help to select AFs in a transparent and informed way and to harmonise methods for deriving OELs. [ABSTRACT FROM AUTHOR]

This paper concerns the global controllability of general nonlinear control systems, which is intimately related to their defining vector fields. We give a necessary and sufficient condition by studying how to enlarge the defining set of vector fields without changing its controllability. Four such approaches are obtained. First, for a given set of vector fields, if one of them is reversible, then the images of these given vector fields under the flow of it can be included without changing the controllability. Second, if two of them are reversible, then their Lie bracket can be included to the given set without changing its controllability. Third, the controllability of a given set of vector fields is preserved by positive span. Finally, the controllability of a given set of vector fields is preserved under closure. For a given nonlinear control system, its controllability is determined as follows. Begin with the defining set of vector fields, step by step, we enlarge it by the aforementioned approaches until its controllability can be readily verified. The power of the proposed approaches is demonstrated by examples. [ABSTRACT FROM AUTHOR]

All green plants alternate between the gametophyte and sporophyte life stages, but only seed‐free vascular plants (ferns and lycophytes) have independent, free‐living gametophytes. Fern and lycophyte gametophytes are significantly reduced in size and morphological complexity relative to their sporophytic counterparts and have often been overlooked in ecological and physiological studies. Understanding the ecological and physiological factors that directly impact this life stage is of critical importance because the ultimate existence of a sporophyte is dependent upon successful fertilization in the gametophyte generation. Furthermore, previous research has shown that the dual nature of the life cycle and the high dispersibility of spores can result in different geographic patterns between gametophytes and their respective sporophytes. This variation in distribution patterns likely exacerbates the separation of selective pressures acting on gametophyte and sporophyte generations, and can uniquely impact a species' ecology and physiology. Here, we provide a review of historical and contemporary methodologies used to examine ecological and physiological aspects of fern gametophytes, as well as those that allow for comparisons between the two generations. We conclude by suggesting methodological approaches to answer currently outstanding questions. We hope that the information covered herein will serve as a guide to current researchers and stimulate future discoveries in fern gametophyte ecology and physiology. [ABSTRACT FROM AUTHOR]

We analyze probability distributions of Birkeland current densities measured by the Active Magnetosphere and Planetary Electrodynamics Response Experiment. We find that the distributions are leptokurtic rather than normal and they are sometimes heavy‐tailed. We fit q‐exponential functions to the distributions and use these to estimate where the largest currents are likely to occur. The shape and scale parameters of the fitted q‐exponential distribution vary with location: The scale parameter maximizes for current densities with the same polarity and in the same location as the average Region 1 current, whereas the shape parameter maximizes for current densities with the same polarity and in the same location as the average Region 2 current. We find that current densities |J| ≥ 0.2 μA m−2 are most likely to occur in the average Region 1 current region, and second most likely to occur in the average Region 2 current region. However, for extreme currents (|J| ≥ 4.0 μA m−2), we find that the most likely location is colocated with the average Region 2 current region on the dayside, at a colatitude of 18°−22°. Plain Language Summary: We use data from a telecommunications satellite network and measure currents flowing along the magnetic field lines above Earth's surface. We look at how strongly these currents flow above different parts of Earth's surface and plot a histogram of the strengths for each of those different locations. We then fit a mathematical model to the histograms to see how those histograms vary with location, and we are able to use the model to work out the probability of a current above a certain strength flowing. This is useful both to gain insights into the physics of the system, but also to gain insights into the potential impacts of these currents on infrastructure on Earth's surface. Key Points: Probability distributions of Birkeland current densities are best‐described by q‐exponential distributionsThe probability of currents at any threshold is higher in the Northern HemisphereExtreme currents are most likely on the dayside at a colatitude of 18°‐22° (colocated with R2) [ABSTRACT FROM AUTHOR]

Studies predicting how the distribution of aquatic organisms will shift with climate change often use projected increases in air temperature or water temperature. However, the assumed correlations between water temperature change and air temperature change can be problematic, especially for mountainous, high elevation streams. Using stream fish assemblage data from 1,442 surveys across a mountain–plains gradient (Wyoming, USA; 1990–2018), we compared the responsiveness of thermal guilds, native status groups, and assemblage structure to projected climate warming from generalized air temperature models and stream‐specific water temperature models. Air temperature models consistently predicted greater range shift differences between warm‐water and cold‐water species, with air temperatures predicting greater increases in occurrence and greater range expansions for warm‐water species. The "over‐prediction" of warm‐water species expansions resulted in air temperature models predicting higher rates of novel species combinations, greater increases in local species richness, and higher magnitudes of biotic homogenization compared with water temperature models. Despite differences in model predictions for warm‐water species, both air and water temperature models predicted that three cold‐water species would exhibit similar decreases in occurrence (decline of 1.0% and 1.8% of sites per 1°C warming, respectively) and similar range contractions (16.6 and 21.5 m elevation loss per 1°C warming, respectively). The "over‐prediction" for warm‐water species is partially attributable to water temperatures warming at slower rates than air temperatures because local, stream‐scale factors (e.g., riparian cover, groundwater inputs) buffer high elevation streams from rising air temperatures. Our study provides the first comparison of how inferences about climate‐induced biotic change at the species‐ and assemblage‐levels differ when modeling with generalized air temperatures versus stream‐specific water temperatures. We recommend that future studies use stream‐specific water temperature models, especially for mountainous, high elevation streams, to avoid the "over‐prediction" of biotic changes observed from air temperature variables. [ABSTRACT FROM AUTHOR]

In this study, a new series representation of the extended k‐gamma function is investigated. A new representation expresses this function as an infinite sum of delta functions. Several researchers have examined this family of functions, but no study has been conducted dealing with the fractional kinetic equation. A new representation proves useful to solve the fractional kinetic equation involving an extended k‐gamma function. Particular cases involving the original gamma function are discussed as corollaries. Such an application of the gamma function is not possible by using known representations; nevertheless, using this representation, new fractional transform formulae are evaluated. A new representation is also worthwhile to compute new integrals of products of the extended k‐gamma functions, proving to be reliable with known identities. Several distributional properties of the extended k‐gamma function are also discussed using Fourier transform. [ABSTRACT FROM AUTHOR]

The current dearth of long‐term insect population trends is a major obstacle to conservation. Occupancy models have been proposed as a solution, but it remains unclear whether they can yield long‐term trends from natural history collections, since specimen records are normally very sparse. A common approach for sparse data is to coarsen its spatial and/or temporal resolution, although coarsening risks violating model assumptions.We (i) test whether occupancy trends of three social wasp (Hymenoptera: Vespidae: Vespinae) species – the common wasp (Vespula vulgaris), the German wasp (Vespula germanica) and the European hornet (Vespa crabro) – have changed in England between 1900 and 2016, and (ii) test the effect of spatiotemporal resolution on the performance of occupancy models using very sparse data. All models are based on an integrated dataset of occurrence records and natural history collection specimen records.We show that occupancy models can yield long‐term species‐specific trends from very sparse natural history collection specimens. We present the first quantitative trends for three Vespinae species in England over 116 years. Vespula vulgaris and V. germanica show stable trends over the time series, whilst V. crabro's occupancy decreased from 1950 to 1970 and increased since 1970. Moreover, we show that spatiotemporal resolution has little effect on model performance, although coarsening the spatial grain is an appropriate method for achieving enough records to estimate long‐term changes.With the increasing availability of biological records, the model formulation used here has the potential to provide novel insights by making use of natural history collections' unique specimen assemblages. [ABSTRACT FROM AUTHOR]

Spatial patterns of biodiversity are inextricably linked to their collection methods, yet no synthesis of bias patterns or their consequences exists. As such, views of organismal distribution and the ecosystems they make up may be incorrect, undermining countless ecological and evolutionary studies. Using 742 million records of 374 900 species, we explore the global patterns and impacts of biases related to taxonomy, accessibility, ecotype and data type across terrestrial and marine systems. Pervasive sampling and observation biases exist across animals, with only 6.74% of the globe sampled, and disproportionately poor tropical sampling. High elevations and deep seas are particularly unknown. Over 50% of records in most groups account for under 2% of species and citizen‐science only exacerbates biases. Additional data will be needed to overcome many of these biases, but we must increasingly value data publication to bridge this gap and better represent species' distributions from more distant and inaccessible areas, and provide the necessary basis for conservation and management. [ABSTRACT FROM AUTHOR]

Proteoglycans (PGs) are largely glycosylated proteins, consisting of a linkage sugar, core proteins, and glycosaminoglycans (GAGs). To date, more than 40 kinds of PGs have been identified, and they can be classified as intracellular, cell surface, pericellular, and extracellular PGs according to cellular locations. To illustrate, extracellular PGs are known for regulating the homeostasis of the extracellular matrix; cell‐surface PGs play a role in mediating cell adhesion and binding various growth factors. In the field of periodontology, PGs are implicated in cellular proliferation, migration, adhesion, contractility, and anoikis, thereby exerting a profound influence on periodontal tissue development, wound repair, the immune response, biomechanics, and pathological process. Additionally, the expression patterns of some PGs are dynamic and cell‐specific. Therefore, determining the roles and spatial‐temporal expression patterns of PGs in the periodontium could shed light on treatments for wound healing, tissue regeneration, periodontitis, and gingival overgrowth. In this review, close attention is paid to the distributions, functions, and potential applications of periodontal PGs. Related genetically modified animal experiments and involved signal transduction cascades are summarized for improved understanding of periodontal PGs. To date, however, there is a large amount of speculation on this topic that requires rigorous experiments for validation. [ABSTRACT FROM AUTHOR]

Indigenous Peoples' lands cover over one‐quarter of Earth's surface, a significant proportion of which is still free from industrial‐level human impacts. As a result, Indigenous Peoples and their lands are crucial for the long‐term persistence of Earth's biodiversity and ecosystem services. Yet, information on species composition on these lands globally remains largely unknown. We conducted the first comprehensive analysis of terrestrial mammal composition across mapped Indigenous lands based on data on area of habitat (AOH) for 4460 mammal species assessed by the International Union for Conservation of Nature. We overlaid each species' AOH on a current map of Indigenous lands and found that 2695 species (60% of assessed mammals) had ≥10% of their ranges on Indigenous Peoples' lands and 1009 species (23%) had >50% of their ranges on these lands. For threatened species, 473 (47%) occurred on Indigenous lands with 26% having >50% of their habitat on these lands. We also found that 935 mammal species (131 categorized as threatened) had ≥ 10% of their range on Indigenous Peoples' lands that had low human pressure. Our results show how important Indigenous Peoples' lands are to the successful implementation of conservation and sustainable development agendas worldwide. Article impact statement: Indigenous Peoples' lands are important for the successful implementation of international conservation and sustainable development agendas. [ABSTRACT FROM AUTHOR]

Summary: This paper addresses the performance of wireless fading channels, namely, Rayleigh, Rician, and Nakagami‐m fading channels, taking both noiseless and additive noisy cases into account. The performance metrics investigated are channel capacity, channel model variance estimation, required average description length based on Shannon entropy, and relative entropy and symbol error probability assessment. Taylor expansion is considered as an approximation for the aforementioned metrics together with the compressed sensing (CS) compressibility rule. Technical comments are provided for supporting simulation results. Mathematical interpretations are provided to support the simulation results along with feasible applications in 5G wireless systems. Conclusions and future research directions finalize the paper. [ABSTRACT FROM AUTHOR]

Statistical downscaling (SD) methods used to refine future climate change projections produced by physical models have been applied to a variety of variables. We evaluate four empirical distributional type SD methods as applied to daily precipitation, which because of its binary nature (wet vs. dry days) and tendency for a long right tail presents a special challenge. Using data over the Continental U.S. we use a 'Perfect Model' approach in which data from a large‐scale dynamical model is used as a proxy for both observations and model output. This experimental design allows for an assessment of expected performance of SD methods in a future high‐emissions climate‐change scenario. We find performance is tied much more to configuration options rather than choice of SD method. In particular, proper handling of dry days (i.e., those with zero precipitation) is crucial to success. Although SD skill in reproducing day‐to‐day variability is modest (~15–25%), about half that found for temperature in our earlier work, skill is much greater with regards to reproducing the statistical distribution of precipitation (~50–60%). This disparity is the result of the stochastic nature of precipitation as pointed out by other authors. Distributional skill in the tails is lower overall (~30–35%), although in some regions and seasons it is small to non‐existent. Even when SD skill in the tails is reasonably good, in some instances, particularly in the southeastern United States during summer, absolute daily errors at some gridpoints can be large (~20 mm or more), highlighting the challenges in projecting future extremes. [ABSTRACT FROM AUTHOR]

The Australian trunk‐boring cycad weevils of the genera Demyrsus Pascoe, 1872 and Siraton Hustache, 1934 (Molytinae) are sometimes considered as cycad pests when they infest planted cycads and can be transported to other countries. In the present study, the taxonomy of Demyrsus and Siraton is reviewed, and four species are recognised: D. meleoides Pascoe, 1872, D. digmon sp. nov., S. internatus (Pascoe, 1870) and S. roei (Boheman, 1843). The discovery of a second species of Demyrsus illustrates a larger diversity of cycad‐associated weevils in Australia than currently known and identifies a further species with the potential to damage and kill cultivated cycads. The species descriptions and diagnoses are supplemented with illustrations of the habitus and salient structures, a distribution map and an identification key to all species of trunk‐boring cycad weevils in Australia. Their potential hosts are identified from a spatial analysis of their distributions and the distributions of the cycad taxa occurring in this range. [ABSTRACT FROM AUTHOR]

Background: This multi‐national study evaluated changes in platelet (PLT) unit distributions at 12 national or regional blood collectors over a 10‐year period. Methods: Data on the total number of PLT distributions, the collection method, that is apheresis vs whole blood‐derived (WBD), the PLT unit characteristics and post‐collection modifications were obtained from 12 national or regional blood collectors from 2008 through 2017. Individual WBD PLT units were converted to apheresis equivalent units (i.e. a dose of PLTs) by dividing by 4, the typical pool size; WBD units that were pooled before distribution were counted as a single dose. Results: Overall at these 12 blood collectors, the total number of PLTs distributed in 2008 was 1 373 200, which rose by 10·2% to 1 513 803 in 2017. The Japanese Red Cross, which distributes only apheresis PLTs, had a 13·4% increase in the number of distributions between the years 2008 and 2017, while the other 11 blood collectors combined demonstrated a 6·8% increase in distributions between these two years. Between the years 2008 and 2017, the changes in the proportion of apheresis, platelet‐rich plasma and buffy coat PLT distributions were −29·9%, −70·7% and 80·0%, respectively. Conclusion: The number of PLT distributions increased during the 10‐year study period despite prophylactic PLT transfusion thresholds having remained fairly consistent over the last decade. Perhaps this increase is in part driven by increased administration of platelets to patients with massive haemorrhage or an increase in stem cell transplantation. The use of buffy coat PLTs is increasing at these collectors. [ABSTRACT FROM AUTHOR]

In recent years, interest in understanding the effects of climate change on species and ecological systems has sharply increased. We quantify and contextualize the current state of knowledge about the effects of contemporary climate change on non‐human primates, a taxon of great ecological and anthropological significance. Specifically, we report findings from a systematic literature search designed to assess the allocation of research effort on primates and climate change and consider how the current distribution of knowledge may be influencing our understanding of the topic. We reveal significant phylogenetic and geographic gaps in our knowledge, which is strongly biased towards lemurs, apes, and a relatively small subset of primate range countries. We show that few analyses investigate changes in primate foods relative to changes in primates themselves or their habitats, and observe that few longitudinal datasets are of sufficient duration to detect effects on the generational scale. We end by identifying areas of research inquiry that would advance our theoretical understanding of primate ecology, evolution, and adaptability, and meaningfully contribute to primate conservation. [ABSTRACT FROM AUTHOR]

The mechanisms that underlie the diversification of Neotropical primates remain contested. One mechanism that has found support is the riverine barrier hypothesis (RBH), which postulates that large rivers impede gene flow between populations on opposite riverbanks and promote allopatric speciation. Ayres and Clutton‐Brock (1992) demonstrated that larger Amazonian rivers acted as barriers, delineating the distribution limits of primate species. However, profound changes in taxonomy and species concepts have led to the proliferation of Neotropical primate taxa, which may have reduced support for their results. Using the most recent taxonomic assessments and distribution maps, we tested the effect of increasing river size on the similarity of opposite riverbank primate communities in the Amazon. First, we conducted a literature review of primate taxonomy and developed a comprehensive spatial database, then applied geographical information system to query mapped primate ranges against the riverine geography of the Amazon watershed to produce a similarity index for opposite riverbank communities. Finally, we ran models to test how measures of river size predicted levels of similarity. We found that, almost without exception, similarity scores were lower than scores from Ayres and Clutton‐Brock (1992) for the same rivers. Our model showed a significant negative relationship between streamflow and similarity in all tests, and found river width significant for the segmented Amazon, but not for multiple Amazon watershed rivers. Our results support the RBH insofar as they provide evidence for the prediction that rivers with higher streamflow act as more substantial barriers to dispersal, and accordingly exhibit greater variation in community composition between riverbanks. Research Highlights: Species similarity on opposite banks in the Amazon was lower than expected. Streamflow and river width predicted species similarity.Results support the riverine barrier hypothesis in that river characteristics can be related to community composition. [ABSTRACT FROM AUTHOR]

Statistical downscaling methods are extensively used to refine future climate change projections produced by physical models. Distributional methods, which are among the simplest to implement, are also among the most widely used, either by themselves or in conjunction with more complex approaches. Here, building off of earlier work we evaluate the performance of seven methods in this class that range widely in their degree of complexity. We employ daily maximum temperature over the Continental U.S. in a "Perfect Model" approach in which the output from a large‐scale dynamical model is used as a proxy for both observations and model output. Importantly, this experimental design allows one to estimate expected performance under a future high‐emissions climate‐change scenario. We examine skill over the full distribution as well in the tails, seasonal variations in skill, and the ability to reproduce the climate change signal. Viewed broadly, there generally are modest overall differences in performance across the majority of the methods. However, the choice of philosophical paradigms used to define the downscaling algorithms divides the seven methods into two classes, of better versus poorer overall performance. In particular, the bias‐correction plus change‐factor approach performs better overall than the bias‐correction only approach. Finally, we examine the performance of some special tail treatments that we introduced in earlier work which were based on extensions of a widely used existing scheme. We find that our tail treatments provide a further enhancement in downscaling extremes. [ABSTRACT FROM AUTHOR]

The identification of geographic areas where the densities of animals are highest across their annual cycles is a crucial step in conservation planning. In marine environments, however, it can be particularly difficult to map the distribution of species, and the methods used are usually biased towards adults, neglecting the distribution of other life‐history stages even though they can represent a substantial proportion of the total population.Here we develop a methodological framework for estimating population‐level density distributions of seabirds, integrating tracking data across the main life‐history stages (adult breeders and non‐breeders, juveniles and immatures). We incorporate demographic information (adult and juvenile/immature survival, breeding frequency and success, age at first breeding) and phenological data (average timing of breeding and migration) to weight distribution maps according to the proportion of the population represented by each life‐history stage.We demonstrate the utility of this framework by applying it to 22 species of albatrosses and petrels that are of conservation concern due to interactions with fisheries. Because juveniles, immatures and non‐breeding adults account for 47%–81% of all individuals of the populations analysed, ignoring the distributions of birds in these stages leads to biased estimates of overlap with threats, and may misdirect management and conservation efforts. Population‐level distribution maps using only adult distributions underestimated exposure to longline fishing effort by 18%–42%, compared with overlap scores based on data from all life‐history stages.Synthesis and applications. Our framework synthesizes and improves on previous approaches to estimate seabird densities at sea, is applicable for data‐poor situations, and provides a standard and repeatable method that can be easily updated as new tracking and demographic data become available. We provide scripts in the R language and a Shiny app to facilitate future applications of our approach. We recommend that where sufficient tracking data are available, this framework be used to assess overlap of seabirds with at‐sea threats such as overharvesting, fisheries bycatch, shipping, offshore industry and pollutants. Based on such an analysis, conservation interventions could be directed towards areas where they have the greatest impact on populations. [ABSTRACT FROM AUTHOR]

Aim: Anthropogenic noise pollution (ANP) is a globally invasive phenomenon impacting natural systems, but most research has occurred at local scales with few species. We investigated continental‐scale breeding season associations with ANP for 322 bird species to test whether small‐scale predictions related to breeding habitat, migratory behaviour, body mass and vocal traits are consistent at broad spatial extents for an extensive group of species. Location: Conterminous USA. Time period: 2004–2011. Major taxa studied: North American breeding birds. Methods: We calculated, for each species, the association between the breeding season and ANP, using spatially explicit estimates of ANP from the National Park Service and weekly estimates of probabilities of occurrence based on observations from the eBird citizen‐science database. We evaluated how the association of the breeding season for each species with ANP was related to expectations based on size, migratory behaviour and breeding habitat. For a subset of species, we used vocal trait data for song duration, pitch and complexity to evaluate hypotheses from the birdsong literature related to habitat complexity and sensitivity to ANP. Results: Species that breed predominantly in anthropogenic environments were associated with twice the level of ANP (~7.4 dB) as species breeding in forested habitats (~3.2 dB). However, we did not find evidence to suggest that birds with higher‐pitched songs are more likely to be found in areas with higher levels of ANP. Residents and migratory species did not differ in associations with ANP, but songs were less complex among forest‐breeding species than non‐forest‐breeding species and increased in complexity with increasing ANP. Main conclusions: Anthropogenic noise pollution is an important factor associated with breeding distributions of bird species in North America. Vocal traits could be useful to understand factors that affect sensitivity to ANP and to predict the potential impact of ANP, although future studies should aim to understand how and why patterns differ across spatial scales. [ABSTRACT FROM AUTHOR]

Aim: To understand how disturbance—here defined as a transient reduction in competition—can shape plant distributions along elevation gradients. Theory suggests that disturbance may increase elevation ranges, especially at the lower range limits, through reduced competitive exclusion. Nevertheless, to date this relationship remains unclear. Location: Mountains of Costa Rica. Methods: We compared the elevation range of woody stems over 10 cm dbh ("trees") observed in plots along two transects spanning a range of elevations in secondary (regrowth) and old‐growth forest (409 and 249 species, respectively). We also estimated these elevation ranges using nationwide data. In addition, we examined the influence of stem size and plot scale basal area (as a measure of competition) on species elevation range limits in the two gradients. Results: In general, tree species ranges increased with elevation. Species in the secondary forest had broader elevation ranges (100–318 m broader than species in the old‐growth forest; Wilcoxon: p‐value <.001). Also, in the secondary transect, individuals with greater diameters had broader elevation ranges than those observed as smaller trees (137 m broader; Kruskal–Wallis: p‐value =.03). The lower range limit of species occurred more frequently in plots with lower (vs. higher) basal area than expected by chance in both forest types. We also observed higher elevation upper limits in old growth, but not in secondary forests, with lower (vs. higher) basal area. Main conclusion: Disturbance relaxes the constraints imposed by competition and extends effective elevation ranges of species, particularly those in secondary forest, to warmer and cooler climates (minimum increase equivalent to about 0.6–1.4°C). Thus, suitable disturbance may assist species persistence under climate change. We believe this is the first study indicating a consistent relation between disturbance and woody plant species distributions along elevation gradients. [ABSTRACT FROM AUTHOR]

The diversity, distribution and species richness of benthic macroinvertebrate fauna as well as benthic environments were examined in the blood cockle Anadara granosa cultivations at Ban Don Bay, Suratthani Province, Southern Thailand during the summer season of April and rainy season of October in 2017. The cockle cultivations of three repeated operating ages (<5 years: S1; 5–10 years: S2; more than 10 years: S3) were selected for the study, and the sampling sites were allocated at the centre of the farm. Results indicated that there were significant differences in species number, individual number and evenness index of benthic macroinvertebrate fauna found in the two sampling seasons (p < .05) and significant differences in individual number and evenness index were found among the sampling sites (p < .05). Significant differences in pH, total phosphorus levels, sulphide levels and organic matter of sediment were found between the sampling seasons (p < .05) and differences in total nitrogen level, organic matter and clay content were found among the sampling sites (p < .05). Among the independent variables analysed, correlation analysis showed no relationship between diversity index, species richness index and evenness index and the abiotic variables (p < .05). The results of the present study suggest that the distribution and diversity variations of the benthic macroinvertebrates community fauna are not affected by all sediment parameters in various repeated cultivation of the blood cockle Anadara granosa in Bandon Bay, Suratthani Province. [ABSTRACT FROM AUTHOR]

Aims: To explore whether wide‐ranging, generalist primates like baboons can be presumed 'resilient' in the face of climate change. We identify environmental variables influencing baboons' current distributions and predict their future potential distributions under different climate change scenarios. Location: Africa and Arabia. Taxon: Baboons, Papio spp. Methods: We used localities for olive, yellow, Guinea, hamadryas, chacma and Kinda baboons together with high‐resolution data on bioclimatic variables, altitude and vegetation to construct species distribution models (SDMs). These SDMs were run under current and future conditions, with future models based on three General Circulation Models (MIROC‐ESM, CCSM4 and HadGEM2‐ES) under two Representative Concentration Pathways (RCP2.6 and RCP6.0) for 2050 and 2070 to explore a range of different possible futures. Results: All SDMs produced AUC values >0.916 suggesting excellent overall performance. Altitude was the most important variable influencing Guinea baboon distributions (contributing 41.6%), temperature seasonality for olive and yellow baboons (47.5% and 35.4% respectively), precipitation of the driest month for hamadryas baboons (24.4%), annual mean precipitation for the Kinda baboon (45.1%) and mean temperature of the driest quarter for chacma baboons (41.4%). Chacma and Kinda baboons are predicted to suffer substantial habitat loss, and Guinea baboons may do the same if conditions aridify as climates warm. In contrast, all models for the olive and hamadryas baboons predicted an increase in suitable habitat and only smaller changes were predicted for the yellow baboon. Main Conclusions: Two or three of six baboon taxa are at risk of significant habitat loss as climates warm despite their apparent ecological flexibility. The chacma and Kinda baboons (both IUCN listed as Least Concern) will be worst affected, followed by the Guinea baboon (Near Threatened) if warming brings aridification. We recommend more focus on biogeographical tools as a means of exploring vulnerabilities in seemingly resilient species. [ABSTRACT FROM AUTHOR]

The cumulative distribution function transform (CDFt) downscaling method has been used widely to provide local‐scale information and bias correction to output from physical climate models. The CDFt approach is one from the category of statistical downscaling methods that operates via transformations between statistical distributions. Although numerous studies have demonstrated that such methods provide value overall, much less effort has focused on their performance with regard to values in the tails of distributions. We evaluate the performance of CDFt‐generated tail values based on four distinct approaches, two native to CDFt and two of our own creation, in the context of a "Perfect Model" setting in which global climate model output is used as a proxy for both observational and model data. We find that the native CDFt approaches can have sub‐optimal performance in the tails, particularly with regard to the maximum value. However, our alternative approaches provide substantial improvement. This study evaluates the tails of the distribution of values generated by the CDFt downscaling method. Output from a climate model under a climate change scenario is used in a "Perfect Model" evaluation. Unsatisfactory performance by CDFt in the tails, especially for the maximum value, can be improved substantially by our own approaches. The figure shows the error distributions for downscaling the maximum value based on CDFt (red) and one of our approaches (blue). [ABSTRACT FROM AUTHOR]

In this paper, we derive an asymptotic expansion for the semi-infinite sum of Dirac- δ functions centered at discrete equidistant points defined by the set [ABSTRACT FROM AUTHOR]

Spatial distributions of many freshwater invertebrates are associated with the concentration of total dissolved solids ( TDS) in streams (usually measured as specific electrical conductivity - EC). These patterns are presumably caused by taxon-specific effects of TDS on the maintenance of ion and water balance, which is energetically expensive and thus could affect fitness. However, no studies have assessed if TDS-related effects on fitness metrics, such as growth and survival, are predictive of distributions., We used stream-side, flow-through microcosms to experimentally determine how TDS concentration influenced three life-history performance measures (growth, mortality and emergence) of 13 species of aquatic insects. We then modelled the relationship between experimentally derived performance measures and both EC optima and minima estimated from field surveys., In the streamside experiment, we exposed taxa to stream water with naturally low (<25 μS cm−1) and moderate (>125 μS cm−1) EC for 83 days, controlling for differences in habitat, temperature, food availability and pH. We measured performance as the differences in specific growth rates, survival and adult emergence between the two treatments., Treatment effects on performance varied among taxa and with performance metric. Survival differences between treatments varied from 1 to 21 days, and specific growth rates differed by 0.07-1.5 day−1. Emergence success was less variable (>20% for only two taxa). Three taxa performed better in the low EC treatment, six in the moderate EC treatment, one had a mixed response and three taxa did not differ between treatments., The best model predicting field-derived EC optima included both survival and specific growth rate as predictors ( R2 = 0.68). Estimates of EC minima were not as strongly related to performance measures as were optima estimates. Taxa with greater performance in the moderate EC treatment had the highest EC optima, indicating that low TDS concentrations could restrict the distributions of taxa adapted to higher TDS concentrations. In contrast to taxa with higher EC preferences, taxa that can tolerate low EC environments will likely be increasingly stressed as stream TDS increases in response to climate and land-use change expected this century. [ABSTRACT FROM AUTHOR]

One of the major uncertainties of 21st century climate change is the potential for shifts to the intensity and frequency of the El Niño Southern Oscillation ( ENSO) cycle. Although this phenomenon is known to have dramatic impacts on ecosystems regionally and globally, the biological consequences of climate change-driven shifts in future ENSO events have been unexplored. Here, we investigate the potential impacts that a persistent El Niño, La Niña, or 'Neutral' phase may have on species distributions. Using MaxEnt, we model the distribution of climatically suitable habitat for three northeast Australian butterfly subspecies ( Doleschallia bisaltide australis, Hypolimnas alimena lamina, and Mycalesis terminus terminus) across the three ENSO phases. We find that the spatial extent and quality of habitat are lowest under conditions that would characterize a persistent El Niño (hot/dry). In contrast, suitable habitat is broadest under the warm/wet conditions associated with La Niña. Statistical analyses of the difference between pair-wise combinations of suitability maps using Hellinger distance showed that projections for each subspecies and ENSO phase combination were significantly different from other combinations. The resilience of these, and other, butterfly (sub)species to changes in ENSO will be influenced by fluctuations in the strength of these events, availability of refugia, and life-history characteristics. However, the population dynamics of wet- and dry-season phenotypes of M. t. terminus and physiological limitations to high temperatures suggest that this subspecies, in particular, may have limited resilience should the strength and frequency of El Niño events increase. [ABSTRACT FROM AUTHOR]

Purpose We propose a method to acquire [ABSTRACT FROM AUTHOR]

Global habitat decline may displace organisms from optimal environments, increasing reliance on ecosystems with lower habitat suitability and availability. For coral reef fishes, potentially marginal mesophotic coral ecosystems (~30-150 m) may be buffered from anthropogenic stressors; however, variation in habitat quality across depths can alter population demographics, reproductive output, and subpopulation size, potentially restricting the ability for peripheral habitats to support declining populations through larval supply. This study incorporated population density, benthic habitat, and depth-stratified population demographics to assess bicolor damselfish (Stegastes partitus) subpopulation reproductive output from a broad geographic region encompassing the known depth distribution of the species, including coral reefs in the Florida Keys (0-35 m depths) and mesophotic reefs (~60-90 m) at Pulley Ridge (PR) on the west Florida Shelf. Results indicated that densities of bicolor damselfish peaked in mid-shelf (10-20 m) and deep-shelf (20-30 m) habitats, and subpopulation sizes and reproductive output peaked at mid-depths (10-20 m) in the Florida Keys and declined as depth increased. Subpopulation egg production was affected by differences in demographics across depths, including fish size, sex ratios, and a lower probability and frequency of spawning in deeper habitats. Despite low population densities on mesophotic reefs, the expansive reef area at PR resulted in an estimated subpopulation size that comprised ~14% of the population in the study region, and ~9% of the total reproductive output, indicating that peripheral mesophotic reefs may be sources of larvae that can subsidize declining populations. Larval dispersal and population connectivity models used to inform ecosystem management should incorporate spatially explicit demographics across depth distributions and habitat availability that have substantial effects on egg production and larval supply. [ABSTRACT FROM AUTHOR]

During the last decade, variance control charts based on different sampling schemes have attracted research interest in the field of statistical process control. These charts used extra (auxiliary) information either for ranking of units or estimation rather than using it for both. The effectiveness of a control chart can be increased by utilizing the auxiliary information for dual purposes. This article is focused on developing a generalized structure of variance control charts based on dual use of auxiliary information under different sampling strategies and runs rules. The generalized structure mainly depends on three auxiliary information-based estimators with dual use of auxiliary information, three bivariate process distributions, and variety of sampling schemes. The performance of the proposed control charts is investigated by assessing the power curve. We have observed that the proposals of the study perform better than its complement. An application example is also provided for practitioners' concerns to monitor the stability of physicochemical parameter of groundwater. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Inequality is anisotropic: its intensity varies by income level. We here develop a new tool, the isograph, to focus on local inequality and illustrate these variations. This method yields three coefficients which summarize the shape of inequality: a main coefficient, α, which measures inequality at the median; and two correction coefficients, β and γ, which pick up any differential curvature at the top and bottom of the distribution. The analysis of a set of 232 microdata samples from 41 different countries in the LIS datacenter archive allows us to provide a systematic overview of the properties of the ABG ( α β γ) coefficients, which are compared to a set of standard indices including Atkinson indices, generalized entropy, Wolfson polarization, and the GB2 distribution. This method also provides a smoothing tool that reveals the differences in the shape of distributions (the strobiloid) and how these have changed over time. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Many studies assume climatic factors are paramount in determining species' distributions, however, biotic interactions may also play a role. For example, pollinators may limit species' ranges if floral abundance or floral attractiveness is reduced at range margins, thus causing lower pollinator visitation and reduced reproductive output. METHODS: To test if pollinators influence the altitudinal distribution of Erythronium montanum (Liliaceae) at Mount Rainier National Park, we asked whether (1) seed production in this species relies on pollinators, (2) seed production and pollen limitation is greatest at range limits, and (3) pollinator visitation rates (either overall or by individual taxonomic groups) reflect patterns of seed production and pollen limitation. RESULTS: From this three-year study, w e established that this plant does rely on pollinators for fruit set and we found that pollen limitation trended toward being higher at the upper range limit in some years, but not consistently year to year. Insect visitation rates did not mirror spatial patterns of pollen limitation, but annually variable pollinator composition suggested differential importance of some pollinator taxonomic groups (specifically, bumblebees may be better pollinators than syrphid flies). CONCLUSIONS: Overall, these results suggest that while pollinators are critical for the reproductive success of this high mountain wildflower, plant-pollinator interactions do not obviously drive the distribution of this species. Nonetheless, high spatio-temporal variability in range-wide plant-pollinator dynamics may complicate responses to climate change. [ABSTRACT FROM AUTHOR]

A nonlinear control system is said to be orbital feedback linearizable if there exist an invertible static feedback and a change of time scale (depending on the state) which transform the system into a linear system. We give geometric necessary and sufficient conditions describing multi-input control-affine systems that are orbital feedback linearizable out of equilibria and in the case of equal controllability indices. We also describe a construction of the time rescaling needed to orbitally linearize the system. Moreover, we analyze close relations between orbital feedback linearizable control-affine systems and control-linear systems that are feedback equivalent to a multi-chained form comparing geometric structures corresponding to both problems. We illustrate our results by two examples, one being a rigid bar moving in [ABSTRACT FROM AUTHOR]

Aim Identifying factors that limit species distributions is a fundamental question in ecology with implications for understanding global biodiversity patterns and species responses to environmental change. Theory suggests that temperature seasonality may affect range size. Species at higher latitudes and elevations experience greater temperature variation, which should lead to broader thermal tolerances and elevational ranges. Research suggests that realized seasonality, or the seasonality species experience when active, may be a better predictor of distributions than annual seasonality. We tested the seasonality hypothesis by examining relationships between environmental factors and elevational range. Location Argentina. Methods We gathered data on ecology and thermal physiology for 33 Liolaemus lizards ( Liolaemidae) and analysed data in phylogenetic comparative analyses using mitochondrial DNA sequences. We used 1000 tree structures and ran phylogenetic generalized least squares analyses on all 33 species and on 23 species in the boulengeri clade to determine if the elevational range of lizards shows a positive relationship with annual and realized seasonality, thermal tolerance, latitude and elevational midpoint of the species distribution. Results Latitude and elevational midpoint were good predictors of elevational range in all models. Annual seasonality was a good predictor of elevational range in models containing 33 species. Variation in phylogenetic tree structure led to differences in the best-fit statistical models. Thermal tolerance and realized seasonality were not good indicators of elevational range. Main conclusions Our findings support some, but not all, of the predictions of the seasonality hypothesis. Species at higher latitudes and elevations have larger elevational ranges, and annual seasonality is partly responsible for this increase. Yet, adult thermal tolerance shows no relationship with elevational range, suggesting that distributions may depend on the physiology of other Liolaemus life stages. Differences in phylogenetic tree structure and the number of species included in analyses can lead to different conclusions regarding the seasonality hypothesis. [ABSTRACT FROM AUTHOR]

As an alternative to the commonly used univariate flood frequency analysis, copula frequency analysis can be used. In this study, 58 flood events at the Litija gauging station on the Sava River in Slovenia were analysed, selected based on annual maximum discharge values. Corresponding hydrograph volumes and durations were considered. Different bivariate copulas from three families were applied and compared using different statistical, graphical and upper tail dependence tests. The parameters of the copulas were estimated using the method of moments with the inversion of Kendall's tau. The Gumbel-Hougaard copula was selected as the most appropriate for the pair of peak discharge and hydrograph volume ( Q-V). The same copula was also selected for the pair hydrograph volume and duration ( V-D), and the Student-t copula was selected for the pair of peak discharge and hydrograph duration ( Q-D). The differences among most of the applied copulas were not significant. Different primary, secondary and conditional return periods were calculated and compared, and some relationships among them were obtained. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This study presents a relationship between two well-known distributions, namely, geometric and binomial distributions. We will provide the statement of our result supported by its precise proof. In addition, we will give an illustrative example to explain the suggested relationship. We will indicate some industrial applications where the derived communicative property may be used. Moreover, the use of this linkage property will be shown in control charting setup. [ABSTRACT FROM AUTHOR]

1. This study examines abundance-occupancy relationships of larval black flies in temperate streams of the south-eastern United States. It is the first study of abundance-occupancy relationships in lotic macro-invertebrate assemblages to focus on a single family. We address the following questions: (i) Do larval black flies show a strong inter-specific abundance-occupancy relationship? (ii) Do widespread and abundant species demonstrate greater niche breadth (NB) or niche position (NP) than do species with limited distributions and low local abundances? (iii) Does the abundance-occupancy relationship change between habitat generalists and specialists? 2. Species abundance was measured as the total mean relative abundance over all sites. Three measures of occupancy were used: occurrence (number of sites occupied), latitudinal extent of occupancy, and longitudinal extent of occupancy. Niche-based indices (breadth and position) were expressed as multivariate indices of habitat variables, reflecting variation in the niche of a species, as opposed to a simple range. 3. Non-ecological factors (sampling, analytical artefacts, phylogenetic nonindependence) accounted for our results and, accordingly, we focus on ecological explanations of inter-specific abundance-occupancy relationships, grounded in niche and meta-population theory. When occupancy was measured as the number of sites at which a species occurred, a strong inter-specific abundance-occupancy relationship was found. Niche-based indices did not have a significant influence on shaping this relationship. When occupancy was measured as geographic extent, the abundance-occupancy relationship was weak or non-significant, although niche-based indices had a significant effect on occupancy. No evidence supported the notion that meta-population dynamics influence abundance- occupancy relationships. Abundance-occupancy relationship is a summation of individual species traits, a point that often receives little attention. [ABSTRACT FROM AUTHOR]

Aim: Protected wildlife habitats provide valuable stepping stones for species that shift their distributions in response to climatic and other environmental changes, but they might also aid the spread of invasive alien species. Here, we quantify the use of protected areas (PAs) by both introduced and natural wetland colonists in the UK to analyse patterns of colonization and examine the propensity of invaders to use PAs. Location: United Kingdom. Methods: We calculate PA associations for six species of wetland birds deliberately introduced to the UK and compare these with eight others that have recently colonized the UK naturally. We assess PA associations at three different stages of establishment - first breeding in each county, early establishment of a population (4-6 years after initial breeding) and subsequent consolidation (14-16 after initial breeding) - and analyse changes in PA association over time. Results: Introduced wetland bird species were less associated with PAs than natural colonists at each stage of establishment. During the later stages of colonization, the PA association of introduced species tended to increase. In contrast, natural colonists usually colonized PAs first, and their established populations subsequently spread into non-PA sites. Main conclusions: The United Kingdom PA network did not facilitate the invasion of introduced species during the initial stages of their colonization, but was vulnerable to colonization as populations established. This is in contrast to natural colonists, which are more reliant on PAs during initial colonization but become less dependent as they establish. During a period of rapid environmental change, PAs have facilitated expansions of natural colonists, without acting as the prime sites for invasion by introduced species. [ABSTRACT FROM AUTHOR]