Limited Range Research Articles

Effects of Climate Change on the Fish Community, and Rhynchocypris kumgangensis (Cypriniformes: Cyprinidae) Distribution in Deogyusan National Park

Rhynchocypris kumgangensis, endemic to Korea, is limited to the upper Hangang River and Gucheondongcheon Stream. As a key and climate-sensitive biological indicator species in the Deogyusan National Park, it has a southern range limit in the Gucheondong Valley. Due to climate change, notable shifts in the activity, distribution, and population of R. kumgangensis on the Gucheondongcheon Stream are expected. This study examined trends between the 2020 field survey and previous surveys (2014–2018) for fish faunal changes at 13 sites in the Deogyusan National Park and for the population changes of R. kumgangensis at four sites in the Gucheondongcheon Stream. At 13 sites, we identified 996 individuals of 17 fish species in seven families, including 2 endangered (Pseudopungtungia nigra, Hemibarbus mylodon) and 11 Korea-endemic species. The Fish Assessment Index (FAI) of the 13 sites in the Deogyusan National Park was analyzed and found to be of A-grade in both the 2020 and past surveys, with high scores in all M1–M8 categories. Both the results of CCA and field surveys between the entire fish community and pH, DO, and water temperature revealed that the population of R. kumgangensis had a narrower distribution range and was more sensitive to water temperature than the same cold-water fish, R. oxycephalus. Climate change has been identified as causing the annual maximum temperature (°C) in the Deogyusan National Park to increase year on year and the R. kumgangensis population to decline, suggesting that the time for conservation efforts is “now”.

Living on the edge – physiological tolerance to frost and drought explains range limits of 35 European tree species

Species distribution models are key to evaluate how climate change threatens European forests and tree species distributions. However, current models struggle to integrate ecophysiological processes. Mechanistic models are complex and have high parameter requirements. Some correlative species distribution models have tried to include traits but so far have struggled to directly connect to ecophysiological processes. Here, we propose a new strategy in which species distributions are based on safety margins which represent species' proximity to their physiological thresholds. We derived frost and drought safety margins for 38 European tree species as the difference between physiological tolerance traits and local maximum stress. We used LT50 and Ψ50 as tolerance traits for frost and drought, respectively, and local minimum temperature and minimum soil water potential as maximum stress. We integrated these safety margins into a species distribution model, which tests if the probability of species presence declines rapidly when the safety margin reaches zero, when physiological stress exceeds the species' tolerance traits. Our results showed thaet 35 of the 38 studied species had their distribution explained by one or both safety margins. We demonstrated that safety‐margins‐based model can be efficiently transferred to species for which occurrence data are not available. The probability of presence dropped dramatically when the frost safety margin reached zero, whereas it was less sensitive to the drought safety margin. This differential sensitivity may be due to the more complex regulation of drought stress, especially as water is a shared resource, whereas frost is not. Our analysis provides a new approach to link species distributions to their physiological limits and shows that, in Europe, frost and drought safety margins are important determinants of species distributions.

Hybrid Mutual Authentication for Vehicle-to-Infrastructure Communication Without the Coverage of Roadside Units

The security issues in Vehicle Ad Hoc Networks (VANETs) are prevalent within Intelligent Transportation Systems (ITS). To ensure the security of vehicle-to-infrastructure (V2I) communication, extensive research on V2I authentication has been conducted in recent years. However, these protocols often overlook the limitations of communication range, leading to failures in V2I communication. Consequently, addressing the challenge of secure V2I communication in areas not covered by distributed roadside units (RSUs) remains a significant task. To address these issues, the current study proposes an Anonymous Certificate-less Hybrid Mutual Authentication Protocol (ACHMAP) based on Vehicle-to-Vehicle-to-Infrastructure (V2V2I) communication. In the proposed protocol, a secure multi-hop link is established through vehicle-to-vehicle (V2V) mutual one-time token authentication. Subsequently, the out-of-coverage vehicle and relevant RSUs complete V2I mutual authentication using signcryption messages transmitted by vehicle nodes. In the security analysis, it is demonstrated that the entire V2V2I stage can resist various security attacks, such as replay attacks, impersonation attacks, and threats to user anonymity, while preserving confidentiality and integrity. We simulated the proposed protocol using Network Simulator 3 (NS-3) to confirm that the authentication mechanism has lower overhead and minimal authentication delay in V2V2I communication.

Magnetic relaxation switch biosensor for detection of Vibrio parahaemolyticus based on photocleavable hydrogel

BackgroundFoodborne pathogens, particularly Vibrio parahaemolyticus (VP) found in seafood, pose significant health risks, including abdominal pain, nausea, and even death. Rapid, accurate, and sensitive detection of these pathogens is crucial for food safety and public health. However, existing detection methods often require complex sample pretreatment, which limits their practical application. This study aims to overcome these limitations by developing a label-free magnetic relaxation switch (MRS) biosensor for the detection of VP, utilizing a photocleavable sol-gel phase transition system for improved efficiency and accuracy. ResultsIn this work, a tag-free magnetic relaxation switch (MRS) biosensor was designed for the detection of Vibrio parahaemolyticus (VP), based on a photocleavable sol-gel phase transition system. A large amount of lithium acyl hypophosphite (LAP), gold nanoparticles (AuNPs), and single-stranded DNA (ssDNA) loaded on the surface of Ti3C2Tx MXene acted as the signal unit LAP-MXene@AuNPs-ssDNA. The pipette tip served as a reaction vessel, and when VP was present, Apt specifically captured VP and released the signal units. The released signal units were then injected into the low-field nuclear magnetic resonance (LF-NMR) test solution, a gel formed by crosslinking of disulfide bonds. The gel was cleaved by LAPs on the signal units under ultraviolet (UV) irradiation, triggering a gel-sol phase transition, which increased transverse relaxation time (T2), thus enabling the detection of VP. Under the optimal experimental conditions, the linear range and detection limit for VP were 102 ∼ 108 CFU/mL and 10 CFU/mL, respectively. Significance and NoveltyThe simplified biometric identification process in the pipette tip reduces errors from multiple sample transfers, enhancing efficiency. The use of photocleavable hydrogel for signal output eliminates issues associated with magnetic material aggregation, significantly improving detection precision. The assay is of good selectivity, stability reproducibility, and convenience, having a broad application prospect in the rapid detection of pathogenic bacteria in the field.

Electrochemical Detection and Characterization of Caffeine in Selected Tea Samples using Polyglycine Modified Carbon Paste Electrode

Glycine was electro-polymerized against a carbon paste electrode (CPE) to produce a polymer film via the electro-oxidation process comprising amino (-NH2) and carboxylic (-COOH) groups, by a cyclic voltammetric. The electrochemical oxidation of caffeine was examined in 0.2 M phosphate buffer solution (PBS). The Polyglycine modified Carbon Paste Electrode (PGMCPE) demonstrates greater electrocatalytic activity for caffeine as compared to the unmodified CPE (UNMCPE). This made it suitable for analyzing caffeine owing to its increased electrode surface area and/or improved electron transport at the electrode surface. By varying the concentration range from 0.05 to 0.9 mM, the relationship between peak current and caffeine concentration was studied and this produced a correlation coefficient of R2 = 0.9987. This method was extremely capable of evaluating caffeine concentrations. Square wave voltammetry (SWV) was utilized to assess the caffeine in tea samples. The sample was analyzed with square wave voltammetry and was made easier with an ideal pH of 12.0. Additionally, the caffeine levels in a tea sample were successfully measured using the linear range and detection limit, and the results showed a good limit of detection (LOD) in comparison to previous literature.

Preconcentration of heavy metal ions using Konjac gum-Co3O4 magnetic hydrogel prior to their determination by ICP-OES

In this study, a hydrogel embedded with magnetic cobalt nanoparticles was synthesized from natural Konjac gum through a simple and low-cost method and its potential for separation and preconcentration of lead, copper, zinc, chromium, cobalt, and cadmium ions was investigated. Determination of the extracted metal ions was carried out using inductively coupled plasma /optical emission spectroscopy. The magnetic property of the hydrogel helps the separation from the solution and improves the adsorption capacity. The proper synthesis of the magnetic hydrogel was confirmed with different characterizations techniques, such as Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy. The effective parameters on the sorbent synthesis and extraction process were studied. Under optimized conditions, the linear range and detection limit were found to be 0.3–100.0 µg L−1 and 34.0 ng L−1 for lead, 0.1–100.0 µg L−1 and 17.0 ng L−1 for chromium, 0.07–100.0 µg L−1 and 10.0 ng L−1 for zinc, 0.07–100.0 µg L−1 and 12.0 ng L−1 for copper, 0.1–100.0 µg L−1 and 15.0 ng L−1 for cadmium and 0.1–100.0 µg L−1 and 21.0 ng L−1 for cobalt, respectively. The developed method was successfully employed for the analysis of the above ions in the real samples including water, fruit and soil.

Mirror hand and its management: a case report

BackgroundMirror hand is a rare congenital anomaly. Most of these cases are sporadic and associated with defective sonic hedgehog during embryogenesis. In this report, we present the case of a child with this rare congenital anomaly and its management.Case presentationA 2.5-year-old Asian female child presented with left-sided Al Qattan type 1A ulnar dimelia with restriction of wrist and elbow range of motion. Radiological examination revealed duplication of ulna with polydactyly. Management of mirror hand is a great surgical challenge, so preoperative planning and staged management is essential for the functional outcome of this condition. We successfully achieved fine and gross motor skills of the hand with acceptable cosmetic results at 2 years of follow-up.ConclusionIt is crucial to remember that early intervention, ideally between 18 and 24 months of age, is key for optimal functional outcomes. Meticulous preoperative planning and surgical technique are essential. Long-term follow-up and parental counseling about the need for supervised physical therapy are important for managing secondary deformities. Additionally, digital subtraction angiography should be performed to rule out any associated neurovascular malformations.

Combining past and contemporary species occurrences with ordinal species distribution modeling to investigate responses to climate change

Many organisms leave evidence of their former occurrence, such as scat, abandoned burrows, middens, ancient eDNA or fossils, which indicate areas from which a species has since disappeared. However, combining this evidence with contemporary occurrences within a single modeling framework remains challenging. Traditional binary species‐distribution modeling reduces occurrence to two temporally coarse states (present/absent), so thus cannot leverage the information inherent in temporal sequences of evidence of past occurrence. In contrast, ordinal modeling can use the natural time‐varying order of states (e.g. never occupied versus previously occupied versus currently occupied) to provide greater insights into range shifts. We demonstrate the power of ordinal modeling for identifying the major influences of biogeographic and climatic variables on current and past occupancy of the American pika Ochotona princeps, a climate‐sensitive mammal. Sampling over five years across the species' southernmost, warm‐edge range limit, we tested the effects of these variables at 570 habitat patches where occurrence was classified either as binary or ordinal. The two analyses produced different top models and predictors – ordinal modeling highlighted chronic cold as the most‐important predictor of occurrence, whereas binary modeling indicated primacy of average summer‐long temperatures. Colder wintertime temperatures were associated in ordinal models with higher likelihood of occurrence, which we hypothesize reflect longer retention of insulative and meltwater‐provisioning snowpacks. Our binary results mirrored those of other past pika investigations employing binary analysis, wherein warmer temperatures decrease likelihood of occurrence. Because both ordinal‐ and binary‐analysis top models included climatic and biogeographic factors, results constitute important considerations for climate‐adaptation planning. Cross‐time evidences of species occurrences remain underutilized for assessing responses to climate change. Compared to multi‐state occupancy modeling, which presumes all states occur in the same time period, ordinal models enable use of historical evidence of species' occurrence to identify factors driving species' distributions more finely across time.

Highly Permeable, Electrically Switchable Filter for Multidimensional Sorting of Suspended Particles

The creation of highly specific particle systems in the nano- and micrometer size range is a challenging task. The demand for particle systems with narrowly distributed properties is increasing in many applications, especially for use in high-tech products. Conventional separation techniques often reach their limits in the micrometer size range or become (labor-)intensive, which makes them economically or ecologically unsustainable. In addition, sorting based on several properties is rarely feasible in just one separator. Dielectrophoretic processes can be a viable option for complex sorting tasks like this, given their ability to address several particle properties and their high degree of selectivity. In this paper, we summarize the progress of a project in which the capability of dielectrophoretic methods for multidimensional sorting of microparticles was investigated. We were able to develop an operation mode for multidimensional sorting of microparticles using dielectrophoresis as well as a scalable electrically switchable filter. This creates a basis for high-throughput and multi-target sorting of technical microparticles using dielectrophoretic processes.

A Dual-Ion Synergistic Catalysis Utilizing Zn2+-Regulated CdSySe1-y ECL Immunosensor Employed for the Ultrasensitive CA19-9 Detection.

Carbohydrate antigen 19-9 is a well-known malignancy biomarker, and its sensitive detection is particularly crucial in the diagnosis and assessment of pancreatic cancer. In this study, an ultrasensitive CA19-9 immunosensor was constructed using the Zn2+-regulated CdSySe1-y (Zn-CdSySe1-y) nanospheres (NSs) as the electrochemiluminescence (ECL) emitter and FeCoS2 nano octahedrons (NOs) as a coreactant enhancer. The microstructure of ternary transition metal chalcogenide CdSySe1-y was precisely tuned by Zn2+ doping to avoid aggregation and thus enable stable and efficient cathodic ECL responses. The bimetallic sulfide FeCoS2 was synthesized using a metal organic framework (MOF) as the template by ion permeation. It was able to catalyze the coreactant efficiently due to the synergistic effect of the Fe2+ and Co2+. The immunosensor exhibited low detection limit (7.6 × 10-5 U mL-1) in the wide linear range of 0.0001-100 U mL-1, offering a sensitive CA19-9 detection method.

Hybrid Control Strategy for LLC Converter Based on Improved Fruit Fly Optimization Algorithm

This paper presents a hybrid control strategy for the LLC resonant converter in X-ray machines, addressing the limitations of voltage gain range under Pulse Frequency Modulation (PFM) and dynamic response under Phase Shift Modulation (PSM). The strategy employs an improved fruit fly optimization algorithm (IFOA) to optimize PI control and integrate Hybrid Phase-Shifted and Frequency-Modulated control. It dynamically adjusts the switching frequency and phase shift angle to maintain output stability and efficiency, ensuring optimal operation under rated conditions. A Matlab-based system simulation model confirmed the stability and accuracy of the IFOA in controlling the converter. Subsequent prototype testing validated the strategy’s effectiveness in reducing conduction losses, enhancing overall efficiency, and demonstrating practical feasibility and superiority.

Does the intervention for adhesive capsulitis in patients with diabetes differ from that for patients without diabetes?: A systematic review.

Adhesive capsulitis (AC) is often accompanied by pain and restriction in range of movement, which long lasting symptoms often have negative impact on patients' work and lives. Since diabetes mellitus (DM) is an independent risk factor for developing AC, and AC with DM have more limitations of joint motion than general people. The aim of the present study is to evaluate the difference of clinical efficacy between diabetes and non-diabetes, and to explore whether AC with diabetes need special intervention compared to non-diabetes. Pubmed NCBI and Embase were searched for studies published in the last 30 years. We conducted a literature search for terms regarding AC and DM on Pubmed NCBI and Embase. A total of 9 studies eligible for inclusion. The affected shoulders in these studies ranged from 26 to 135, 460 shoulders (551 participants) in total, including 166 shoulders in diabetic group and 394 shoulders in non-diabetic/idiopathic group. Interventions included shock wave therapy, hydrodilatation, arthroscopic capsular release, manipulation under cervical nerve root block. Evaluation indicators included pain, certain shoulder questionnaires, range of motion. Positive clinical efficacy were emerged after interventions between the 2 groups. The studies that better improvement of pain in non-diabetic/idiopathic group were 2 of 6, that of certain shoulder questionnaires were 4 of 8, that of range of motion were 3 of 6. Whether AC combined with DM or not, the current treatment could achieve positive clinical effectiveness and there is some statistical evidence show that the curative effect of AC combined with DM is worse than non-diabetic. In other words, the available evidence suggests that patients with DM might require additional rehabilitation measures with routine glycemic control.

Adaptive learning rate algorithms based on the improved Barzilai–Borwein method

Objective:The Barzilai–Borwein(BB) method is essential in solving unconstrained optimization problems. The momentum method accelerates optimization algorithms with exponentially weighted moving average. In order to design reliable deep learning optimization algorithms, this paper proposes applying the BB method in four variants to the optimization algorithm of deep learning. Findings:The momentum method generates the BB step size under different step range limits. We also apply the momentum method and its variants to the stochastic gradient descent with the BB step size. Novelty:The algorithm’s robustness has been demonstrated through experiments on the initial learning rate and random seeds. The algorithm’s sensitivity is tested by choosing different momentum factors until a suitable momentum factor is found. Moreover, we compare our algorithms with popular algorithms in various neural networks. The results show that the new algorithms improve the efficiency of the BB step size in deep learning and provide a variety of optimization algorithm choices.

Will climate change constrain the altitudinal range of threatened species? Experimental evidence from a biodiversity hotspot.

A fundamental goal in ecology and evolution is to explain the factors that shape species' abundance and range limits. Evaluating the performance of early life-stages across an altitudinal gradient can be valuable for understanding what factors shape range limits and for predicting how plant species may respond to climate change. To experimentally evaluate the presence of local adaptation in a threatened palm (Euterpe edulis) at early life-stages, we reciprocally sowed seeds at two contrasting elevations. In addition, to evaluate the effect of seed predation on E. edulis seed germination and seedling establishment, seed addition experiments were conducted at three different elevations. Our results showed no evidence of local adaptation in the early life-stages for the two E. edulis populations. We observed lower germination and seedling performance of both E. edulis populations at the low-elevation site. The exclusion of seed predation increased seedling establishment across all elevations. Seed predation and dry soil conditions were the main factors that constrained seedling establishment at the upper altitudinal limit and at the lower elevation, respectively. Climate change in the study area will result in warmer and drier environmental conditions. The lack of local adaptation and the lower performance of both E. edulis populations in warm and dry conditions, combined with a higher seed predation at the upper altitudinal limit, might cause an altitudinal range contraction, increasing the vulnerability of this threatened species to climate change.

A Perspective of Multi-Reflecting TOF MS.

Time-of-flight mass spectrometry (TOF MS) excels in rapid and high-sensitivity analysis, making it a cornerstone of analytical chemistry. But as sample complexity explodes in omics studies, so does the need for higher resolving power to ensure accurate results. Traditional TOF instruments face a challenge: achieving high resolution often requires a very large instrument. To overcome this limitation, scientists developed alternative designs for TOF analyzers called multi-pass TOF analyzers (MPT). These MPT analyzers come in two main configurations: multi-turn (MTT) and multi-reflecting (MRT). Drawing on the authors' extensive experience, this review describes two decades of MPT advancements. It highlights the critical development of optimized analyzer designs, tracing the evolution towards mirror-based MRT instruments, generally providing superior resolution and spatial acceptance compared to MTT. While the manuscript attempts to overview MTT advances, it primarily focuses on MRT technology. Additionally, the review explores the role of orthogonal accelerators and trap pulse converters, comparing their efficiency and the dynamic range limits imposed by space charge effects. By comparing various MRT configurations and commercially available instruments, the review sets out to inform and empower researchers so they can make informed decisions about MRT mass spectrometers.

Commodity Wi-Fi-Based Wireless Sensing Advancements over the Past Five Years.

With the compelling popularity of integrated sensing and communication (ISAC), Wi-Fi sensing has drawn increasing attention in recent years. Starting from 2010, Wi-Fi channel state information (CSI)-based wireless sensing has enabled various exciting applications such as indoor localization, target imaging, activity recognition, and vital sign monitoring. In this paper, we retrospect the latest achievements of Wi-Fi sensing using commodity-off-the-shelf (COTS) devices from the past 5 years in detail. Specifically, this paper first presents the background of the CSI signal and related sensing models. Then, recent studies are categorized from two perspectives, i.e., according to their application scenario diversity and the corresponding sensing methodology difference, respectively. Next, this paper points out the challenges faced by Wi-Fi sensing, including domain dependency and sensing range limitation. Finally, three imperative research directions are highlighted, which are critical for realizing more ubiquitous and practical Wi-Fi sensing in real-life applications.

CoWO4/Reduced Graphene Oxide Nanocomposite-Modified Screen-Printed Carbon Electrode for Enhanced Voltammetric Determination of 2,4-Dichlorophenol in Water Samples.

Water pollution with phenolic compounds is a serious environmental issue that can pose a major threat to the water sources. This pollution can come from various agricultural and industrial activities. Phenolic compounds can have detrimental effects on both human health and the environment. Therefore, it is essential to develop and improve analytical methods for determination of these compounds in the water samples. In this work, the aim was to design and develop an electrochemical sensing platform for the determination of 2,4-dichlorophenol (2,4-DCP) in water samples. In this regard, a nanocomposite consisting of CoWO4 nanoparticles (NPs) anchored on reduced graphene oxide nanosheets (rGO NSs) was prepared through a facile hydrothermal method. The formation of the CoWO4/rGO nanocomposite was confirmed via different characterization techniques. Then, the prepared CoWO4/rGO nanocomposite was used to modify the surface of a screen-printed carbon electrode (SPCE) for enhanced determination of 2,4-DCP. The good electrochemical response of the modified SPCE towards the oxidation of 2,4-DCP was observed by using cyclic voltammetry (CV) due to the good properties of CoWO4 NPs and rGO NSs along with their synergistic effects. Under optimized conditions, the CoWO4/rGO/SPCE sensor demonstrated a broad linear detection range (0.001 to 100.0 µM) and low limit of detection (LOD) (0.0007 µM) for 2,4-DCP determination. Also, the sensitivity of CoWO4/rGO/SPCE for detecting 2,4-DCP was 0.3315 µA/µM. In addition, the good recoveries for determining spiked 2,4-DCP in the water samples at the surface of CoWO4/rGO/SPCE showed its potential for determination of this compound in real samples.

Niche Theory and Species Range Limits Along Elevational Gradients: Perspectives and Future Directions

Despite two centuries of research, the mechanisms underlying the formation of species’ elevational range limits remain poorly understood. The climatic variability hypothesis highlights the role of climatic conditions in shaping species’ thermal tolerance and distribution ranges, while the species interactions–abiotic stress hypothesis underscores the relative importance of biotic factors and abiotic stress along environmental gradients. We emphasize Darwin's perspective on the ubiquity of interspecific competition across climatic gradients and the importance of understanding how climate modulates biotic interactions to shape species distributions. Niche theory provides a comprehensive framework, combined with empirical research, to explore how environmental gradients influence species traits, leading to context-dependent species interactions that constrain distributions. In particular, the application of the concept of environmentally weighted performance can further elucidate these complex ecological mechanisms. Future research should integrate multiple approaches, including field and laboratory manipulative experiments, theoretical modeling, and interdisciplinary collaboration, to improve our understanding of species distributions in mountain regions and to inform biodiversity conservation strategies in the face of rapid environmental change.

MOF-confined ultrafine nanozymes with enhanced catalysis for sensitive colorimetric detection of glucose

The constrained enzymatic activity and aggregation challenges encountered of nanozymes pose an obstacle to their practical utility, necessitating a strategy to alleviate this problem and improve the enzymatic catalytic efficiency. Herein, MOF-confined ultrafine ZnIrOx clusters (ZnIrOx/ZnIrMOFs) nanozyme have been synthesized by controlling the in-situ growth of ZnIrOx via a one-pot method. Notably, due to the domain-limiting effect of MOF, the ZnIrOx clusters with small size grew uniformly in the structure of ZnIrMOFs nanosheets, while the presence of Zn atoms improved the crystallinity of the MOF phase and the dispersion of ZnIrOx clusters. Moreover, the obtained ZnIrOx/ZnIrMOFs exhibited excellent oxidase- and peroxidase-like activities and better substrate affinity, which can directly and effectively catalyze chromogenic reaction to produce corresponding color and signal changes. Adopting this strategy, we established a visual, sensitive, and selective colorimetric method for glucose detection with a linear range and detection limit of 2.66–319 μM and 1.9 μM, respectively. The successful detection of glucose in real serum and food samples implies the promising MOF-confined ultrafine nanozymes in biomedical diagnostics and in food industry.

Biogeographic Patterns in Density, Recruitment, Body Size and Zonation of Rocky Intertidal Predators Suggest Increased Population Vulnerability Near Southern Range Limits

ABSTRACTAimSurveying the demography of populations near species range edges may indicate their vulnerability to range contractions or local extinction as the climate changes. In the rocky intertidal, not only are latitudinal ranges constricted by thermal stress, but tides also create zonation or a ‘vertical range’ driven by sharp environmental gradients. By investigating demographics along the latitudinal and vertical ranges simultaneously, we can investigate whether populations may be vulnerable to a changing climate.LocationRocky intertidal habitats along west coast of the United States.TaxaOchre sea star Pisaster ochraceus, six‐armed sea star Leptasterias spp., emarginate whelks (Nucella ostrina and N. emarginata) and channeled whelk N. canaliculata.MethodsIn 2018, we surveyed the demographics of the taxa above at 33 sites spanning > 11° latitude from central Oregon to southern California, near the southern range limits of each taxon. We counted and sized individuals from the high to low intertidal zone. To understand how environmental stress changed with latitude, we evaluated intertidal temperatures in situ, as well as tidal extremes, tidal amplitude and wave exposure using offshore buoys.ResultsFor all taxa, population density, the relative proportion of smaller individuals (except for emarginate whelks) and the upper vertical limits on the shore declined from north to south as temperatures increased and high tide height, tidal amplitude and wave heights decreased. In addition, smaller individual Leptasterias spp. generally inhabited lower shore levels while smaller individual emarginate whelks inhabited higher shore levels coastwide. For N. canaliculata, smaller animals were higher on shore northward, but lower on shore southward.Main ConclusionsWhile this study is a snapshot in time and cannot assess impacts of climate change, our surveys suggest environmentally‐related demographic limitation toward southern range limits and demographically vulnerable southern populations. Therefore, a warming climate may cause local extinctions or range contractions near southern limits.