Range Shifts Research Articles

Climate change impacts on Mediterranean fisheries: A sensitivity and vulnerability analysis for main commercial species

Climate-induced projected range shifts of exploited species would lead to a redistribution of stocks. Evaluating the combined ecological and socio-economic consequences of projected changes in Mediterranean fisheries due to climate change has remained largely unexplored. This study aims to identify the most affected stocks by climate change and more vulnerable countries in the region. Thus, we calculated the species specific sensitivity per country for 17 harvested species of significant importance. Then, we evaluated the vulnerability index for Mediterranean countries. Results show that temperate-cold species, i.e., Sprattus sprattus and Solea solea appear the most sensitive species. In contrast, temperate-warm species like the bogue showed the lowest sensitivity. Egypt, Tunisia, and Libya are the most vulnerable countries due to their comparatively high exposure to global warming and low adaptive capacity. At the same time, Slovenia, France, and Croatia have the lowest vulnerability because of their low exposure and sensitivity and remarkably high adaptive capacity. The southern Mediterranean countries would be the most vulnerable to climate-induced effects on marine fisheries. The region seriously needs adequate and adopted on-time adaptation and mitigation policies to lessen potential risks to harvested species and stocks and guarantee the contribution of fisheries to the economy and food security in the long-term.

Compact Single-Unit Two-Bit Reflection-Type Phase Shifters with Large Phase Shift Range

Multi-bit phase shifters are typically implemented by cascading multiple phase-shifting units, therefore incurring large dimensions and higher insertion losses. This paper presents highly compact single-unit two-bit reflection-type phase shifters (SUTBRTPSs), with large phase shifts range and lower insertion loss by using only one 3-dB hybrid coupler, unlike traditional multi-bit reflection-type phase shifters. To achieve this, two identical dual-voltage controlled reactance blocks (DVCRBs) are loaded to the 3-dB hybrid directional coupler at through and coupled ports, and 04 states of phase shifts are obtained between the input and isolated ports. Each DVCRB consists of 03 open-circuited transmission lines and switching p-i-n diodes and provides half of the required susceptance to achieve the desired phase shifts. Design theory is presented in detail, and for validation and demonstration, two typical SUTBRTPSs (0°/45°/90°/135° and 0°/22.5°/180°/202.5°) are designed, fabricated and measured. Being implemented in a single-unit structure, the proposed method yields highly compact dimensions of 0.44 λg × 0.46 λg and 0.54 λg × 0.46 λg, respectively. The simulation and measurements results are in good agreement and indicate maximum insertion losses of 1.7 and 2.1 dB with a return loss better than 20 dB and phase error of less than 1.5°.

Changes in parasite species distributions could be driven by host range expansions: the case of hybridisation between two Australian reptile ticks

Anthropogenic stressors such as climate change and diminishing habitats cause widespread disturbances in species distributions for a variety of taxa. Range shifts and hybridisation following secondary contact become of particular importance when it comes to parasites such as ticks, as they are dependent on their host distributions and can carry numerous harmful pathogens. We aimed to determine if two parapatric reptile tick species, Amblyomma albolimbatum and A. limbatum, hybridise at their parapatric boundary by comparing morphological and genomic variation using single nucleotide polymorphisms. Our results show that both tick species were genomically distinct, but hybridisation has occurred. We found a hybrid and an A. limbatum outside of their previously known range, suggesting there could have been a shift in tick distribution. What were thought to be hybrids due to intermediate morphological traits were not hybrids but morphological variants of the parental species. This information suggests more distinctive morphological features are needed for identifying these tick species and that novel environmental conditions and a broadening of tick niche due to hybridisation could increase host exposure to different pathogens.

The turnover of plant-frugivore interactions along plant range expansion: consequences for natural colonization processes.

Plant-animal mutualisms such as seed dispersal are key interactions for sustaining plant range shifts. It remains elusive whether the organization of interactions with seed dispersers is reconfigured along the expansion landscape template and, if so, whether its effects accelerate or slow colonization. Here we analyse plant-frugivore interactions in a scenario of rapid population expansion of a Mediterranean juniper. We combined network analyses with field surveys, sampling interactions between individual plants and frugivores by DNA-barcoding and phototrapping over two seasons. We assess the role of intrinsic and extrinsic intraspecific variability in shaping interactions and we estimate the individual plant contributions to the seed rain. The whole interaction network was highly structured, with a distinct set of modules including individual plants and frugivore species arranged concordantly along the expansion gradient. The modular configuration was partially shaped by individual neighbourhood context (density and fecundity) and phenotypic traits (cone size). Interaction reconfiguration resulted in a higher and more uneven propagule contribution, with most effective dispersers having a prominent role at the colonization front stand, where a distinct subset of early arriving plants dominated the seed rain. Our study offers new insights into the key role of mutualistic interactions in colonization scenarios by promoting fast plant expansion processes.

Impact of Postoperative Changes in Brain Anatomy on Target Volume Delineation for High-Grade Glioma.

High-grade glioma has a poor prognosis, and radiation therapy plays a crucial role in its management. Every step of treatment planning should thus be optimised to maximise survival chances and minimise radiation-induced toxicity. Here, we compare structures needed for target volume delineation between an immediate postoperative magnetic resonance imaging (MRI) and a radiation treatment planning MRI to establish the need for the latter. Twenty-eight patients were included, with a median interval between MRIs (range) of 19.5 (8-50) days. There was a mean change in resection cavity position (range) of 3.04 ± 3.90 (0-22.1) mm, with greater positional changes in skull-distant (>25 mm) resection cavity borders when compared to skull-near (≤25 mm) counterparts (p < 0.001). The mean differences in resection cavity and surrounding oedema and FLAIR hyperintensity volumes were -32.0 ± 29.6% and -38.0 ± 25.0%, respectively, whereas the mean difference in midline shift (range) was -2.64 ± 2.73 (0-11) mm. These data indicate marked short-term volumetric changes and support the role of an MRI to aid in target volume delineation as close to radiation treatment start as possible. Planning adapted to the actual anatomy at the time of radiation limits the risk of geographic miss and might thus improve outcomes in patients undergoing adjuvant radiation for high-grade glioma.

Butterfly species respond differently to climate warming and land use change in the northern Alps

Climate change has a worldwide impact on biodiversity and ecosystem functions, in particular by causing shifts in species distributions and changes in species communities. Here, we analyse altitudinal range shifts of 30,604 lowland butterfly and burnet moth records from 119 species over the past seven decades across the federal state of Salzburg (northern Austria) spanning an altitudinal gradient of >2500 m. For each species, we compiled species-specific traits on their ecology, behaviour, and life-cycle. During the study period, the butterflies have shifted their average occurrence and also lower and upper occurrence limits >300 m uphill. This shift is particularly obvious for the last ten years. Habitat generalist and mobile species exhibited strongest and habitat specialist and sedentary species weakest shifts. Our results underline that the effects of climate change have a strong and currently increasing impact on the patterns of species distribution and local community composition. Hence, we confirm the observation that ubiquistic, mobile species with a broad ecological amplitude can cope better with environmental changes than specialist and sedentary species. Furthermore, the strong changes in land use in lowland areas might additionally enhanced this up-hill shift.

Mechanochromic photonic fibers composed of strain responsive colloidal crystals and spandex yarns

Mechanochromic photonic fibers can realize a visual dynamic color response to external stimuli, and are widely used in colorimetric sensing, smart display, and medical care. At present, colloidal crystals-based mechanochromic photonic fibers with a core-sheath structure have been successfully prepared by electrophoretic deposition and dip-coating. However, problems such as the complicated preparation process and the limited range of color change are still unsolved and hinder the applications of mechanochromic photonic fibers. Here, a mechanochromic photonic fiber with a wide color shift range is prepared by a simple and effective strategy. The fiber is fabricated by coating elastic rubber containing a non-close-packed array of silica particles onto spandex yarn. The obtained photonic fiber displays a structural color that can be controlled by adjusting the diameter and volume fraction of silica particles. Under stretching, the fiber shifts from red to blue with a color change range of 127 nm. More importantly, it achieves reversible color change in the visible range under mechanical strain. These mechanochromic photonic fibers based on colloidal crystals and spandex yarns are promising for smart wearables, display textiles, and visual sensors.

Not the expected poleward migration: Impact of climate change scenarios on the distribution of two endemic evergreen broad-leaved Quercus species in China

One of the key strategies for species to respond to climate change is range shift. It is commonly believed that species will migrate towards the poles and higher elevations due to climate change. However, some species may also shift in opposite directions (i.e., equatorward) to adapt to changes in other climatic variables beyond climatic isotherms. In this study, we focused on two evergreen broad-leaved Quercus species endemic to China and used ensemble species distribution models to project their potential distribution shifts and extinction risk under two shared socioeconomic pathways of six general circulation models for the years 2050 and 2070. We also investigated the relative importance of each climatic variable in explaining range shifts of these two species. Our findings indicate a sharp reduction in the habitat suitability for both species. Q. baronii and Q. dolicholepis are projected to experience severe range contractions, losing over 30 % and 100 % of their suitable habitats under SSP585 in the 2070s, respectively. Under the assumption of universal migration in future climate scenarios, Q. baronii is expected to move towards the northwest (~105 km), southwest (~73 km), and high elevation (180–270 m). The range shifts of both species are driven by temperature and precipitation variables, not only annual mean temperature. Specifically, precipitation seasonality and temperature annual range were the most crucial environmental variables, causing the contraction and expansion of Q. baronii and contraction of Q. dolicholepis, respectively. Our results highlight the importance of considering additional climatic variables beyond the annual mean temperature to explain species range shifts in multiple directions.

Effects of chain composition of PBAT on the supercritical CO2 foaming and degradation behavior

Poly (butylene adipate-co-butylene terephthalate) (PBAT) with different copolymer compositions and molecular weights exhibits unique foaming behavior and dimensional stability when supercritical CO2 is used as a blowing agent. With an increase in the content of butylene glycol terephthalate (BT) from 43% to 61%, the melting point and crystallinity of PBAT increase. Consequently, the foaming temperature range of PBAT shifts toward a narrower, higher temperature zone, i.e., from 70 – 120 °C to 135 –160 °C under 13 MPa CO2 pressure. Additionally, CO2 solubility and desorption rate decrease, while PBAT exhibits a higher compression modulus and better foam dimensional stability. For similar BT contents, an increase in the molecular weight of PBAT widened the foaming temperature window and increased the cell density of the foam. It is noteworthy that increasing the BT content of PBAT to 52% not only ensures good dimensional stability of the PBAT foams, but also good biodegradability of PBAT. In addition, the effect of foam structure on degradation behavior was investigated. It was found that the PBAT foams with a higher volume expansion, larger cell size, and lower cell density degrade faster.

Population-Based Evidence of Climate Change Adaptation in an Endangered Plant Endemic to a Biodiversity Hotspot.

Climate change is expected to impact both the population structure and geographic distribution of plants. Species distribution models are widely used to assess range shifts and the vulnerability of plants to climate change. Despite the abundance of modeling studies, little is known about how existing populations respond to climate change. We investigated the demographic structure and vulnerability to climate change in Anemone moorei, a sub-shrub with a highly restricted distribution in a biodiversity hotspot. We improved the distribution knowledge through intensive field work. We conducted a census of stem length as a proxy for age for all known populations. We used ensemble forecasting to project distributions considering 10 future climate scenarios and developed a novel climate change vulnerability index for the species' distribution. We found that the mean stem length decreases and the proportion of young plants increases, while the size of fruiting plants decreases as A. moorei faces greater climate change vulnerability. We interpret these results as evidence for the onset of recent adaptation to climate change, consisting of reduced adult longevity and an earlier onset of reproduction. As a result of these changes, the proportion of juveniles in the population increases.

Temperature change effects on marine fish range shifts: a meta-analysis of ecological and methodological predictors

Temperature change effects on marine fish range shifts: a meta-analysis of ecological and methodological predictors

Shifts in the composition and distribution of Pacific Arctic larval fish assemblages in response to rapid ecosystem change.

The Pacific Arctic marine ecosystem has undergone rapid changes in recent years due to ocean warming, sea ice loss, and increased northward transport of Pacific-origin waters into the Arctic. These climate-mediated changes have been linked to range shifts of juvenile and adult subarctic (boreal) and Arctic fish populations, though it is unclear whether distributional changes are also occurring during the early life stages. We analyzed larval fish abundance and distribution data sampled in late summer from 2010 to 2019 in two interconnected Pacific Arctic ecosystems: the northern Bering Sea and Chukchi Sea, to determine whether recent warming and loss of sea ice has restricted habitat for Arctic species and altered larval fish assemblage composition from Arctic- to boreal-associated taxa. Multivariate analyses revealed the presence of three distinct multi-species assemblages across all years: (1) a boreal assemblage dominated by yellowfin sole (Limanda aspera), capelin (Mallotus catervarius), and walleye pollock (Gadus chalcogrammus); (2) an Arctic assemblage composed of Arctic cod (Boreogadus saida) and other common Arctic species; and (3) a mixed assemblage composed of the dominant species from the other two assemblages. We found that the wind- and current-driven northward advection of warmer, subarctic waters and the unprecedented low-ice conditions observed in the northern Bering and Chukchi seas beginning in 2017 and persisting into 2018 and 2019 have precipitated community-wide shifts, with the boreal larval fish assemblage expanding northward and offshore and the Arctic assemblage retreating poleward. We conclude that Arctic warming is most significantly driving changes in abundance at the leading and trailing edges of the Chukchi Sea larval fish community as boreal species increase in abundance and Arctic species decline. Our analyses document how quickly larval fish assemblages respond to environmental change and reveal that the impacts of Arctic borealization on fish community composition spans multiple life stages over large spatial scales.

The genetic basis of the leafy seadragon's unique camouflage morphology and avenues for its efficient conservation derived from habitat modeling.

The leafy seadragon certainly is among evolution's most "beautiful and wonderful" species aptly named for its extraordinary camouflage mimicking its coastal seaweed habitat. However, limited information is known about the genetic basis of its phenotypes and conspicuous camouflage. Here, we revealed genomic signatures of rapid evolution and positive selection in core genes related to its camouflage, which allowed us to predict population dynamics for this species. Comparative genomic analysis revealed that seadragons have the smallest olfactory repertoires among all ray-finned fishes, suggesting adaptations to the highly specialized habitat. Other positively selected and rapidly evolving genes that serve in bone development and coloration are highly expressed in the leaf-like appendages, supporting a recent adaptive shift in camouflage appendage formation. Knock-out of bmp6 results in dysplastic intermuscular bones with a significantly reduced number in zebrafish, implying its important function in bone formation. Global climate change-induced loss of seagrass beds now severely threatens the continued existence of this enigmatic species. The leafy seadragon has a historically small population size likely due to its specific habitat requirements that further exacerbate its vulnerability to climate change. Therefore, taking climate change-induced range shifts into account while developing future protection strategies.

Estimating process‐based model parameters from species distribution data using the evolutionary algorithm CMA‐ES

Abstract Two main types of species distribution models are used to project species range shifts in future climatic conditions: correlative and process‐based models. Although there is some continuity between these two types of models, they are fundamentally different in their hypotheses (statistical relationships vs. mechanistic relationships) and their calibration methods (SDMs tend to be occurrence data driven while PBMs tend to be prior driven). One of the limitations to the use of process‐based models is the difficulty to parameterize them for a large number of species compared to correlative SDMs. We investigated the feasibility of using an evolutionary algorithm (called covariance matrix adaptation evolution strategy, CMA‐ES) to calibrate process‐based models using species distribution data. This method is well established in some fields (robotics, aerodynamics, etc.), but has never been used, to our knowledge, in ecology, despite its ability to deal with very large space dimensions. Using tree species occurrence data across Europe, we adapted the CMA‐ES algorithm to find appropriate values of model parameters. We estimated simultaneously 27–77 parameters of two process‐based models simulating forest tree's ecophysiology for three species with varying range sizes and geographical distributions. CMA‐ES provided parameter estimates leading to better prediction of species distribution than parameter estimates based on expert knowledge. Our results also revealed that some model parameters and processes were strongly dependent, and different parameter combinations could therefore lead to high model accuracy. We conclude that CMA‐ES is an efficient state‐of‐the‐art method to calibrate process‐based models with a large number of parameters using species occurrence data. Inverse modelling using CMA‐ES is a powerful method to calibrate process‐based parameters which can hardly be measured. However, the method does not warranty that parameter estimates are correct because of several sources of bias, similarly to correlative models, and expert knowledge is required to validate results.

Effects of climate change on the potential distribution of a dominant, widely distributed oak species, Quercus candicans, in Mexico

Mexican temperate forests are among the most biodiverse in the world. At present, they face anthropogenic pressures and climatic changes. Quercus candicans is a canopy-dominant, widely distributed species common in the moist habitats of these ecosystems. Its ecological importance, habitat vulnerability, and wide distribution make it a useful model of the vulnerability of Mexican tree forest species to climate change. We used ecological niche modeling to estimate future climatic suitability for this species and its potential range shifts under two emissions scenarios and three-time frames. We also identified areas where novel climates could arise and where predictions should be interpreted cautiously. Additionally, we analyzed how climatic suitability could change across the national protected areas system. In both emissions scenarios, areas with suitable climatic conditions were predicted to experience a net reduction of more than 40% by 2070. This corresponds to more than 100 000 km2 becoming climatically unsuitable. In the national protected areas, we forecast a contraction of approximately 30%. Climatic novelty increased considerably in the higher emissions scenario (RCP 8.5), accounting for 10% of the Mexican temperate mountains, compared to 1% on RCP 4.5. Areas of expansion of suitability not intersected by novel climates occur in areas highly affected by land-use change and other anthropogenic pressures. Effective protection of temperate forests’ tree species such as Q. candicans would need to allow migrations across altitudinal gradients, as areas of stability and expansion of climatic suitability are forecasted to occur at higher altitude sections of mountain ranges.

Echo pulses for background suppression by optimal control.

Materials used to construct magic-angle-spinning NMR probes can contain NMR active nuclei that produce a significant amount of background signal. Because these materials are located outside the sample coil, the use of spatially selective pulses to remove the background is a popular approach for background suppression. However, previously suggested spatially selective pulses suffer from limited excitation bandwidths, which may make them unsuitable for the acquisition of nuclei with a large chemical shift range. Here, a pulse (OC-BACK) is presented, which has been developed by optimal control, which has a flat profile of ~120 kHz with respect to off-resonance effects and extended pass and suppression bands with respect to the nominal nutation frequency. The presented solution is large enough to be effective for background suppression schemes in 19 F magic-angle-spinning NMR at medium and low magnetic fields.

Convergence Rates for Learning Linear Operators from Noisy Data

This paper studies the learning of linear operators between infinite-dimensional Hilbert spaces. The training data comprises pairs of random input vectors in a Hilbert space and their noisy images under an unknown self-adjoint linear operator. Assuming that the operator is diagonalizable in a known basis, this work solves the equivalent inverse problem of estimating the operator's eigenvalues given the data. Adopting a Bayesian approach, the theoretical analysis establishes posterior contraction rates in the infinite data limit with Gaussian priors that are not directly linked to the forward map of the inverse problem. The main results also include learning-theoretic generalization error guarantees for a wide range of distribution shifts. These convergence rates quantify the effects of data smoothness and true eigenvalue decay or growth, for compact or unbounded operators, respectively, on sample complexity. Numerical evidence supports the theory in diagonal and non-diagonal settings.

Microclimate Refugia: Comparing Modeled to Empirical Near-Surface Temperatures on Rangeland

Microhabitats can provide thermal niches that affect geographic range shifts of species as the climate changes and provide refuges for pest and beneficial insect populations in agricultural regions. The spatial distribution of microhabitats is influenced by topography that can influence local extinction and recolonization by animal populations. Scaling local temperature-dependent processes to a regional scale of population expansion, and contraction requires the validation of biophysical models of near surface temperatures. We measured temperature at 2.5 cm above and below ground at 25 sites in each of the two regions: southern and northern Utah, USA. Using NichMapR version 3.2.0, we modeled the temperature at these same sites with local slopes and aspects for four years for the former and eight years for the latter region. Empirical and modeled air temperatures differed by 7.4 °C, on average, and soil temperatures differed less (4.4 °C, on average). Site-specific additions of hill shading at 25 m distance or soil parameters did not improve the agreement of the empirical and modeled temperatures. A hybrid model for air temperature that incorporated soil temperature at 0 cm depth when snow depth exceeded 3 cm resulted in an average improvement of 8% that was as great as 31%. Understanding biological processes at the regional scale and in projected future climates will continue to require biophysical modeling. To achieve the widest applications possible, biophysical models such as NichMapR need to be validated with empirical data from as wide a variety of altitudes, latitudes, soil types, and topographies wherein organisms currently inhabit and where their ranges might expand to in the future.

High lability of global niche and range in the Giant African Snail (Lissachatina fulica): Small niche expansions resulting in large range shifts

As a major source of global change, biological invasions have received increasing attention in past decades. Niche and range dynamics of alien invasive species provide essential evidence for understanding mechanisms underlying biological invasions. However, to our knowledge few relevant studies on mollusks have been reported. Here, from the perspective of climatic suitability, we investigated niche and range shifts of the Giant African Snail (Lissachatina fulica), one of the world’s most invasive mollusks. We observed that, compared with its native counterpart, this invasive snail could survive in environments with wider temperature ranges. The invasive snail showed a wider niche breadth and larger potential range than its native counterpart, and occupied different niche and range positions, indicating its high lability in terms of niche and range. This invasive Giant African Snail did not conform to the niche and range conservatism hypotheses, probably due to the influence of human introductions and niche releasing. Given that large shifts in range size can result from small niche expansions, making niche shifts a more important indicator for biological invasion assessments than range shifts. While most invasive species show low lability in niche space, highly labile niche was observed in the Giant African Snail, indicating that strategies to prevent biological invasions by this invasive mollusk should be prioritized. Our study, to certain extent, could further our understanding on the niche shifts and range dynamics between the invasive mollusks and their native counterparts.

Detectability of Anatomical Changes With Prompt-Gamma Imaging: First Systematic Evaluation of Clinical Application During Prostate-Cancer Proton Therapy

The development of online-adaptive proton therapy (PT) is essential to overcome limitations encountered by day-to-day variations of the patient's anatomy. Range verification could play an essential role in an online feedback loop for the detection of treatment deviations such as anatomical changes. Here, we present the results of the first systematic patient study regarding the detectability of anatomical changes by a prompt-gamma imaging (PGI) slit-camera system. For 15 patients with prostate cancer, PGI measurements were performed during 105 fractions (201 fields) with in-room control computed tomography (CT)acquisitions. Field-wise doses on control CT scans were manually classified as whether showing relevant or non-relevant anatomical changes. This manual classification of the treatment fields was then used to establish an automatic field-wise ground truth based on spot-wise dosimetric range shifts, which were retrieved from integrated depth-dose (IDD) profiles. To determine the detection capability of anatomical changes with PGI, spot-wise PGI-based range shifts were initially compared with corresponding dosimetric IDD range shifts. As final endpoint, the agreement of a developed field-wise PGI classification model with the field-wise ground truth was determined. Therefore, the PGI model was optimized and tested for a subcohort of 131 and 70 treatment fields, respectively. The correlation between PGI and IDD range shifts was high, ρpearson=0.67 (p < 0.01). Field-wise binary PGI classification resulted in an area under the curve of 0.72 and 0.80 for training and test cohorts, respectively. The model detected relevant anatomical changes in the independent test cohort, with a sensitivity and specificity of 74% and 79%, respectively. For the first time, evidence of the detection capability of anatomical changes in prostate-cancer PT from clinically acquired PGI data is shown. This emphasizes the benefit of PGI-based range verification and demonstrates its potential for online-adaptive PT.