Small Size Range Research Articles

A Hierarchical Model for Estimating Exposure-Response Curves from Multiple Studies of Household Air Pollution

Estimating flexible exposure-response curves is critical for quantifying the impacts of environmental exposures on health. In intervention trials targeting household air pollution, the limited range of concentrations and small sample sizes of individual studies are important factors that may be limiting their statistical power. Pooling data from multiple studies provides an opportunity to increase power for estimating the exposure-response relationship.We present hierarchical approaches to modeling exposure concentrations and combining data from multiple studies to estimate a common exposure-response curve. The models are designed to accommodate features relevant to many environmental epidemiology studies: exposure measurements and outcome ascertainments that are irregularly spaced across time, clustered by individual and groups of individuals, and impacted by seasonal trends. The exposure concentration model additionally incorporates shrinkage to reduce error from high-variance observations. The exposure-response curve model provides a flexible, semi-parametric estimate of the joint exposure-response relationship across multiple studies from different times and contexts.We demonstrate this modeling approach using data from three studies of cookstoves and acute lower respiratory infections in children in Nepal.

Methods Matter: Methods for Sampling Microplastic and Other Anthropogenic Particles and Their Implications for Monitoring and Ecological Risk Assessment

To inform mitigation strategies and understand how microplastics affect wildlife, research is focused on understanding the sources, pathways, and occurrence of microplastics in the environment and in wildlife. Microplastics research entails counting and characterizing microplastics in nature, which is a labor-intensive process, particularly given the range of particle sizes and morphologies present within this diverse class of contaminants. Thus, it is crucial to determine appropriate sampling methods that best capture the types and quantities of microplastics relevant to inform the questions and objectives at hand. It is also critical to follow protocols with strict quality assurance and quality control (QA/QC) measures so that results reflect accurate estimates of microplastic contamination. Here, we assess different sampling procedures and QA/QC strategies to inform best practices for future environmental monitoring and assessments of exposure. We compare microplastic abundance and characteristics in surface-water samples collected using different methods (i.e., manta and bulk water) at the same sites, as well as duplicate samples for each method taken at the same site and approximate time. Samples were collected from 9 sampling sites within San Francisco Bay, California, USA, using 3 different sampling methods: 1) manta trawl (manta), 2) 1-L grab (grab), and 3) 10-L bulk water filtered in situ (pump). Bulk water sampling methods (both grab and pump) captured more microplastics within the smaller size range (<335 µm), most of which were fibers. Manta samples captured a greater diversity of morphologies but underestimated smaller-sized particles. Inspection of pump samples revealed high numbers of particles from procedural contamination, stressing the need for robust QA/QC, including sampling and analyzing laboratory blanks, field blanks, and duplicates. Choosing the appropriate sampling method, combined with rigorous, standardized QA/QC practices, is essential for the future of microplastics research in marine and freshwater ecosystems. Integr Environ Assess Manag 2021;17:282-291. © 2020 SETAC.

Microstructural evolution and mechanical properties of multi-directionally forged SiP/ZA22 composite

The effect of multi-pass multi-directional forging (MDF) on the microstructure and mechanical properties of Zn–22Al–xSi (X = 4 and 8 wt. %) alloy, also known as SiP/ZA22 composite, was investigated. MDF process was applied at 100 °C for one, three, and five passes with the strain of 0.47 per pass. According to the results, MDF refined and homogenized the composites microstructure so that the average size of primary Si (SiP) particles reduced from 25.0 µm and 30.4 µm in as-cast ZA22-4Si and ZA22-8Si composites to about 6.2 µm and 7.3 µm in five-pass MDFed condition, respectively, and their distribution shifted to the smaller size range. Mechanical properties tests revealed that multi-pass MDF has softened the investigated composite. For instance, the hardness, tensile strength, and shear strength of ZA22-4Si composite reduced from 83 HV, 280 MPa, and 165 MPa in as-cast condition to about 58 HV, 160 MPa, and 118 MPa in the five-pass MDFed sample, respectively. This is while its fracture strain increased from 15% to about 40% with the strain rate of 1.2 × 10–3 s−1.

Face Masks and Respirators in the Fight against the COVID-19 Pandemic: A Review of Current Materials, Advances and Future Perspectives.

The outbreak of COVID-19 has spread rapidly across the globe, greatly affecting how humans as a whole interact, work and go about their daily life. One of the key pieces of personal protective equipment (PPE) that is being utilised to return to the norm is the face mask or respirator. In this review we aim to examine face masks and respirators, looking at the current materials in use and possible future innovations that will enhance their protection against SARS-CoV-2. Previous studies concluded that cotton, natural silk and chiffon could provide above 50% efficiency. In addition, it was found that cotton quilt with a highly tangled fibrous nature provides efficient filtration in the small particle size range. Novel designs by employing various filter materials such as nanofibres, silver nanoparticles, and nano-webs on the filter surfaces to induce antimicrobial properties are also discussed in detail. Modification of N95/N99 masks to provide additional filtration of air and to deactivate the pathogens using various technologies such as low- temperature plasma is reviewed. Legislative guidelines for selecting and wearing facial protection are also discussed. The feasibility of reusing these masks will be examined as well as a discussion on the modelling of mask use and the impact wearing them can have. The use of Artificial Intelligence (AI) models and its applications to minimise or prevent the spread of the virus using face masks and respirators is also addressed. It is concluded that a significant amount of research is required for the development of highly efficient, reusable, anti-viral and thermally regulated face masks and respirators.

Evolutionary patterns in the geographic range size of Atlantic Forest plants

Species’ geographic range size is arguably the single most important predictor of vulnerability to extinction and a key metric in ecology. Despite this, patterns of specific variation in range size and their underlying reasons are still poorly understood. For example, hypotheses on how evolutionary history affects range size have scarcely been tested. To address these questions, we focused on Brazil's Atlantic Forest flora, one of the most species‐rich in the world, relatively well‐known and highly threatened. We investigated whether and how lineages’ diversification rate, number of species and age are associated with species’ geographic range size. We estimated the extent of occurrence and area of occupancy of each of 13 283 plant species native to the Atlantic Forest region based on over 500 000 unique records. We used phylogenetic least squares and logistic regressions to analyze how the predictors affect the geographic range size. On average, the higher the diversification rate and number of species in the lineage, the smaller the species range size and the higher the proportion of species with vulnerably small range size. Lineage age showed no clear effect on average range size. The results support our expectations that dynamics of diversification and taxonomic richness considerably affect the species range size. Finally, this work reveals poorly known patterns of range size variation and some of the mechanisms driving variation in range size and vulnerability to extinction.

Trait evolution and historical biogeography shape assemblages of annual killifish

AbstractAimDifferent species assemblages of annual killifish possess replicated body size distributions yet have unique sets of species in each area of endemism. Here, we use models of trait evolution and historical biogeography to discover how size variation originated and has been restructured.LocationSouth America.TaxonAustrolebias (Cyprinodontiformes).MethodsWe sampled 63 individuals from 26 Austrolebias species. Using phylogenetic trees (BEAST2), data on environmental variables at sampling locations and size data, we compare different models for trait evolution (SURFACE, l1OU) of body size and niche traits. We model the historical biogeography of the areas of endemism (BioGeoBEARS) and use both analyses in combination to reconstruct the history of four species assemblages.ResultsWe present new phylogenetic trees for Austrolebias and use them to show that large size principally arose within a single area driven by a shifted selection optimum for a subset of the species in that area. We suggest that ecological interactions triggered size divergence and that this large‐bodied lineage subsequently spread to two other areas. A second assemblage may have been shaped by adaptation to a new environment without an associated increase in size divergence. A third assemblage, which has the smallest size range and the most recent origin, is phylogenetically clustered, and we found no evidence of environmental filtering.Main conclusionsAssemblage similarity in Austrolebias is the result of contrasting ecological, evolutionary and historical processes. Modelling trait evolution together with historical biogeography can help to disentangle the complex histories of multispecies assemblages. This approach provides context to commonly used tests investigating the role of ecological processes from phylogenetic data and generates new testable hypotheses on the processes that generated trait diversity and assemblage similarity.

Industrial applications of selected JFS articles

Industrial applications of selected <i>JFS</i> articles

Transposable element abundance correlates with mode of transmission in microsporidian parasites

The extreme genome reduction and physiological simplicity of some microsporidia has been attributed to their intracellular, obligate parasitic lifestyle. Although not all microsporidian genomes are small (size range from about 2 to 50 MB), it is suggested that the size of their genomes has been streamlined by natural selection. We explore the hypothesis that vertical transmission in microsporidia produces population bottlenecks, and thus reduces the effectiveness of natural selection. Here we compare the transposable element (TE) content of 47 microsporidian genomes, and show that genome size is positively correlated with the amount of TEs, and that species that experience vertical transmission have larger genomes with higher proportion of TEs. Our findings are consistent with earlier studies inferring that nonadaptive processes play an important role in microsporidian evolution.

Cationic oxidized microporous rice starch: Preparation, characterization, and properties.

The combination of enzymolysis of compound enzyme, oxidation of sodium hypochlorite, and cationic etherification of 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTMA) was selected for the functionalization of rice starch (RS) to better raise the performances. The results showed that the oxidation and etherification could improve the acid and alkali resistance of RS, and enhanced its thermal stability. The crystalline structure of RS was an A-type, the enzymolysis, oxidation, and etherification did not change the structural type, while the crystallinity degree of RS derivatives was all reduced. The enzymolysis, oxidation, and etherification altered the pasting properties of RS, and could effectively decrease the setback and breakdown of RS. The oxidation of sodium hypochlorite not only damaged RS particles containing no micropores, but also destroyed the particles containing the micropores. The enzymolysis and oxidation more seriously destroyed the crystalline region than cationic etherification. The oxidation could increase the enthalpy change of RS, whereas the enzymolysis and etherification decreased its enthalpy change. In addition, the enzymolysis and oxidation could lead to the evident increase in average size of RS. The cationic etherification was able to improve the adsorption of Cu2+ on RS, whereas the low oxidation could only slightly ameliorate the adsorption of Cu2+ . PRACTICAL APPLICATION: Cationic oxidized microporous rice starch as an adsorbent, slow-release agent, and flocculant will be well used in food, medicine, pesticide, papermaking, waste water treatment, and so on owing to its abundant micropores, anionic groups, and cationic groups as well as small particle size and narrow size range.

Effect of sediment particle size on polycyclic aromatic hydrocarbon bioaccessibility and degradation by ultrasound

The effect of particle size on sonochemical desorption, degradation and change in bioaccessibility of polycyclic aromatic hydrocarbons (PAHs) on contaminated sediments was investigated. Batch experiments were performed with the whole sediment (WS < 850 μm), a large size range fraction (150 μm < LSR < 850 μm), and a small size range fraction (SSR < 150 μm) of the whole sediment. PAH degradation followed pseudo first-order kinetics; PAHs on LSR sediments underwent more rapid degradation than on SSR and WS sediments (νPAH,LSR > νPAH,WS > νPAH,SSR). In addition, a higher sediment slurry concentration resulted in slower degradation of PAHs. Results are consistent with the more rapid particle size reduction of the LSR. More rapid particle size reduction and faster PAH degradation for the LSR fraction combined with analysis of particle velocities in both size ranges indicates that microjets as opposed to particle–particle collisions due to shockwaves are effective in rapid particle size reduction and PAH degradation. Moreover, the bioaccessible fraction (FPAH,fast,t) of sorbed PAHs in both particle size fractions was found to increase with sonication time but was more rapid with the LSR. Likewise, the more tightly bound PAHs, those in the slow desorbing fraction (FPAH,slow,t) of PAHs, decreased faster with sonication of LSR particles compared to SSR particles, consistent with the trend of particle size reduction. Results of this study suggest that ultrasonic treatment is more effective for larger size particle sediments, although sonication is also viable for small sediment sizes.

Rapid growth of new atmospheric particles by nitric acid and ammonia condensation

A list of authors and their affiliations appears at the end of the paper New-particle formation is a major contributor to urban smog1,2, but how it occurs in cities is often puzzling3. If the growth rates of urban particles are similar to those found in cleaner environments (1–10 nanometres per hour), then existing understanding suggests that new urban particles should be rapidly scavenged by the high concentration of pre-existing particles. Here we show, through experiments performed under atmospheric conditions in the CLOUD chamber at CERN, that below about +5 degrees Celsius, nitric acid and ammonia vapours can condense onto freshly nucleated particles as small as a few nanometres in diameter. Moreover, when it is cold enough (below −15 degrees Celsius), nitric acid and ammonia can nucleate directly through an acid–base stabilization mechanism to form ammonium nitrate particles. Given that these vapours are often one thousand times more abundant than sulfuric acid, the resulting particle growth rates can be extremely high, reaching well above 100 nanometres per hour. However, these high growth rates require the gas-particle ammonium nitrate system to be out of equilibrium in order to sustain gas-phase supersaturations. In view of the strong temperature dependence that we measure for the gas-phase supersaturations, we expect such transient conditions to occur in inhomogeneous urban settings, especially in wintertime, driven by vertical mixing and by strong local sources such as traffic. Even though rapid growth from nitric acid and ammonia condensation may last for only a few minutes, it is nonetheless fast enough to shepherd freshly nucleated particles through the smallest size range where they are most vulnerable to scavenging loss, thus greatly increasing their survival probability. We also expect nitric acid and ammonia nucleation and rapid growth to be important in the relatively clean and cold upper free troposphere, where ammonia can be convected from the continental boundary layer and nitric acid is abundant from electrical storms4,5.

Particle-induced oxidative damage by indoor size-segregated particulate matter from coal-burning homes in the Xuanwei lung cancer epidemic area, Yunnan Province, China

Size-segregated samples of airborne particulate matter were collected at the coal-burning homes of the Hutou high lung cancer epidemic village and a comparison site Xize village of the Xuanwei County, Yuanan Province, by an Anderson Cascade Impact Sampler in winter and spring to study the toxicological characteristics of different-sized particles. The DNA damage caused by the water-soluble fractions of these size-segregated particles was analyzed by the plasmid scission assay, and the trace element compositions were determined by Inductively Coupled Plasma Mass Spectrometry. The DNA damage rate from the airborne particles in the high lung cancer incidence area was higher than that in Xize village. The different-sized particles have highly varying DNA damage rates, with the values being greater in the small size range than in the large size range. The particle-induced DNA damage rates had a significantly positive correlation with total water-soluble trace elements. Further analysis of the individual elements indicated that the water-soluble heavy metals Zn, Cu, Cd, Rb, Cs, and Sb had a positive correlation with the particle-induced DNA damage, implying that these water-soluble heavy metals played an important role in the DNA damage. The Sr had a negative correlation with the particle-induced DNA damage, suggesting that the water-soluble Sr might counter DNA damage. The mass concentrations of the total and individual water-soluble trace elements were mostly enriched in the small particle size ranges, thus implying the indoor airborne particles in the small size ranges would have a higher health risk.

Rare species perform worse than widespread species under changed climate

Predicting how species, particularly rare and endangered ones, will react to climate change is a major current challenge in ecology. Rare species are expected to have a narrower niche width than more widespread species. However, we know little whether rare species are also less able to cope with new climatic conditions. To simulate climate change, we transplanted 35 plant species varying in rarity to five botanical gardens in Switzerland, differing in altitude. For each species we calculated the difference in climate between their natural habitats and the novel climate of the respective botanical garden. We found that species with a small range size had generally lower survival and biomass production than widespread species (57% higher biomass and 10% higher survival in species with a range size of 390 grid cells occupied than in species with two grid cells occupied). Moreover, rare plant species survived less when the amount of precipitation differed more from the one in their natural range, indicating a higher susceptibility to climate change. Widespread species, in contrast, survived equally well under all climates and even increased their biomass under wetter or drier conditions. Our study indicates that rarer species are less able to cope with changes in climate compared to more widespread ones, which might even benefit from these changes. This indicates that already rare and endangered plant species might suffer strongly from future climate change.

The combination of palm and rapeseed oils emerges as a good dietary alternative for optimal growth and balanced lipid accumulation in juvenile gilthead sea bream reared at an elevated temperature

The aquaculture sector needs to develop new tools to optimally increase production for feeding, while facing future environmental changing conditions. One of the major improvements in this industry has been reducing the usage of fishmeal and fish oil (FO) in diet formulations to promote a more sustainable production. In this line and considering global warming, in the present study, juvenile gilthead sea bream were fed a diet with a 60% of FO substitution by vegetable oils (VO) containing mainly palm oil (P) (80% of the VO content) and maintained at 21 or 28 °C. Furthermore, in the condition of elevated temperature, fish were fed with two other diets with the same level of FO substitution and containing either 80% of the VO content of rapeseed oil (R) or an equilibrated combination of both VO (named PR). High temperature induced a significant increase in growth, but a reduction in the hepatosomatic and viscerosomatic indexes, and circulating triglycerides. Otherwise, significant differences were not found among the fish fed the three distinct diets at 28 °C for any of the somatic or plasma parameters analyzed. In the adipose tissue, the higher number of adipocytes of smaller size in fish maintained at 28 °C compared to fish at 21 °C, suggested an activation of adipogenesis despite the gene expression of peroxisome proliferator-activated receptor gamma (pparg) was significantly decreased. Furthermore, lipid droplets of smaller area and downregulation of the fat translocase cd36 and the fatty acid binding protein fabp1 were found in the liver of fish reared at 28 °C compared to those at 21 °C. Concerning differences among dietary groups, fish fed R diet showed in the liver a more extensive surface area occupied by lipid droplets of bigger size, while contrarily, fish fed PR diet had the smallest area filled with smaller lipid droplets. In adipose tissue, PR diet-fed fish had also adipocytes within the smaller size range. These histological data, together with the significant upregulation of several transcription factors (i.e. ppars) and genes related to lipid transport in the two tissues, indicated that the PR diet could be the most equilibrated for gilthead sea bream, to grow at a high rearing temperature while avoiding excessive fat accumulation. Thus, this study highlights the need of fine-tuning the substitution of FO by VO in the elaboration of feeds for this species to assure proper growth and physiological status in a future global warming scenario.

Reptile responses to anthropogenic habitat modification: A global meta‐analysis

AbstractAimThe aim was to determine how reptile populations respond to anthropogenic habitat modification and determine whether species traits and environmental factors influence such responses.LocationGlobal.Time period1981–2018.Major taxa studiedSquamata.MethodsWe compiled a database of 56 studies reporting how habitat modification affects reptile abundance and calculated standardized mean differences in abundance (Hedges’ g). We used Bayesian meta‐analytical models to test whether responses to habitat modification depended on body size, clutch size, reproductive mode, habitat specialization, range size, disturbance type, vegetation type, temperature and precipitation.ResultsBased on 815 effect sizes from 376 species, we found an overall negative effect of habitat modification on reptile abundance (mean Hedges’ g = −0.43, 95% credible intervals = −0.61 to −0.26). Reptile abundance was, on average, one‐third lower in modified compared with unmodified habitats. Small range sizes and small clutch sizes were associated with more negative responses to habitat modification, although the responses were weak and the credible intervals overlapped zero. We detected no effects of body size, habitat specialization, reproductive mode (egg‐laying or live‐bearing), temperature or precipitation. Some families exhibited more negative responses than others, although overall there was no phylogenetic signal in the data. Mining had the most negative impacts on reptile abundance, followed by agriculture, grazing, plantations and patch size reduction, whereas the mean effect of logging was neutral.Main conclusionsHabitat modification is a key cause of reptile population declines, although there is variability in responses both within and between species, families and vegetation types. The effect of disturbance type appeared to be related to the intensity of habitat modification. Ongoing development of environmentally sustainable practices that ameliorate anthropogenic impacts is urgently needed to prevent declines in reptile populations.

Effect of Pressure on the Gas Atomizer to Fabricate Stainless Steel Metal Powder

Metal powder is used in the Powder Metallurgy (PM) application process. Most of the metals used in the PM are stainless steel made by the gas atomization process. This study uses the free fall gas atomizer. The material was used to produce the metal powder from various forms of stainless steel 304 raw material, which is melted in an electric induction furnace. This method is very practical to be applied in the large-scale metal processing industries. While the gas pressure variation results show that metal powder with a smaller size will be produced more using high gas pressure. The free fall gas atomizer has successfully produced stainless steel 304 metal powder with the size &lt;40 μm and have a spherical shape. The well-rounded sphericity for 8 bar pressure, 10 bar pressure, and 12 bar pressure are 61.1%, 41.7%, and 37.5% respectively. It can be concluded that 12 bar pressure produces the smallest size range of powder about &lt;40 µm with the most quantity about 1.11%wt, followed by 10 bar pressure about 0.41%wt and 8 bar pressure about 0.07%wt.

Operative time comparison of aquablation, greenlight PVP, ThuLEP, GreenLEP, and HoLEP

The BPH surgical armamentarium is composed of a rapidly expanding number of technologies and techniques. These include greenlight photovaporization of the prostate (PVP), greenlight enucleation of the prostate (GreenLEP), holmium laser enucleation of the prostate (HoLEP), thulium laser enucleation of the prostate (ThuLEP) and, more recently, the aquablation procedure. To the best of our knowledge, no direct comparison in operative time has been performed. Data for this study were pooled from five sources. For aquablation, patient-level data from four studies of the aquablation procedure were provided by the device manufacturer as well as from a high-volume commercial user. PVP, GreenLEP, HoLEP, and ThuLEP were performed by high-volume, experienced experts. Endpoints included total operative time, resection time, and proportion of total operative time for resection. General linear models were used to evaluate the relationship between prostate volume (or other continuous predictors) and procedure time. Total procedure time was related to prostate size. Except for the small prostate size range (size < 40cc), at any given prostate volume, procedure time was highest for PVP, intermediate for LEPs, and lowest for Aquablation. The relationship between procedure time and prostate size (i.e., slope of the fitted lines) was 0.16min/g for aquablation, 0.32min/g, 0.28min/g and 0.32min/g for GreenLEP, HoLEP and ThuLEP, respectively, and 0.63min/g for PVP. In our analysis of pooled data of multi-surgical techniques and technologies, aquablation provided the lowest operative time across all prostate volumes. PVP had the longest procedure time for prostates > 40cc.

A heavy load miniature six-component force sensing mechanism with hybrid branches

The heavy-load force sensing mechanisms with small size and wide range have always been a challenge. To tackle this challenge, we propose a parallel six-component force sensing mechanism with sensitive measuring branches and high load-bearing branches based on the design idea of hybrid branch. Based on the virtual work principle and the geometric compatibility condition, the stiffness model and force mapping relationship of the mechanism are deduced, which provide the theoretical basis for the mechanism. Further, the comparison between the numerical calculation and the simulation values of the force sensing mechanism shows that the mathematical model is in good agreement with the finite element model. Finally, a calibration testing platform is built to analyze the measuring performances of the force sensing mechanism. By using the least square method to analyze the experimental data, the calibration matrix is obtained and the maximum nonlinear error is 1.65%.

Structural Evolution and Stability Trend of Small-Sized Gold Clusters Aun (n = 20-30).

Structural evolution and stability pattern of pure neutral gold clusters Aun in the small size range of n = 20-30 are examined using density functional theory (DFT) calculations. The equilibrium geometries are either confirmed or determined, and some new ground state structures are identified. The most stable configurations of Au21-Au23 sizes are formed by adding extra gold atoms to the highly stable pyramidal structure of Au20, while flat-cage shapes are the best candidates for the global minima of both Au24 and Au25. For larger sizes of n = 26-30, pyramidal motifs tend to dominate the lower-lying population rather than tubular conformations as previously reported. The energy gaps, excitation energies, and exciton binding energies are also computed to test out the performance of the computational methods employed. Accordingly, a density functional with long-range exchange effects is highly recommended to quantitatively investigate both the ground and excited states of pure gold clusters.

The relative importance of biotic and abiotic determinants of temporal occupancy for avian species in North America

AbstractAimWe examined the relative importance of competitor abundance and environmental variables in determining the species distributions of 175 bird species across North America. Unlike previous studies, which tend to model distributions in terms of presence and absence, we take advantage of a geographically extensive dataset of community time series to model the temporal occupancy of species at sites throughout their expected range.LocationNorth America.Time period2001–2015.Major taxa studiedOne hundred and seventy‐five bird species.MethodsWe calculated variation in temporal occupancy across species’ geographic ranges and used variance partitioning and Bayesian hierarchical models to evaluate the relative importance of (a) the abundance of potential competitors and (b) the environment (elevation, temperature, precipitation, vegetation index) for determining temporal occupancy. We also created a null model to test whether designated competitor species predicted variation in temporal occupancy better than non‐competitor species.ResultsOn average, the environment explained more variance in temporal occupancy than competitor abundance, but this varied by species. For certain species, competitor abundance explained more variance than the environment. Migrant species with smaller range sizes and greater range overlap with competitors had a higher proportion of variance explained by competitor abundance than the environment. The abundance of competitor species had a stronger effect on focal species temporal occupancy than non‐competitor species in the null model.Main conclusionsTemporal occupancy represents an underutilized method for describing species distributions that is complementary to presence/absence or abundance. Geographic variation in temporal occupancy was explained by both biotic and abiotic drivers, and abiotic drivers explained more variation in temporal occupancy than abundance on average. Species traits also play a role in determining whether variation in temporal occupancy is best explained by biotic or abiotic drivers. The results of our study can improve species distribution models, particularly by accounting for competitive interactions.