Timing determines zooplankton community responses to multiple stressors.

Human activities and climate change cause abiotic factors to fluctuate through time, sometimes passing thresholds for organismal reproduction and survival. Multiple stressors can independently or interactively impact organisms; however, few studies have examined how they interact when they overlap spatially but occur asynchronously. Fluctuations in salinity have been found in freshwater habitats worldwide. Meanwhile, heatwaves have become more frequent and extreme. High salinity pulses and heatwaves are often decoupled in time but can still collectively impact freshwater zooplankton. The time intervals between them, during which population growth and community recovery could happen, can influence combined effects, but no one has examined these effects. We conducted a mesocosm experiment to examine how different recovery times (0-, 3-, 6-week) between salt treatment and heatwave exposure influence their combined effects. We hypothesized that antagonistic effects would appear when having short recovery time, because previous study found that similar species were affected by the two stressors, but effects would become additive with longer recovery time since fully recovered communities would respond to heatwave similar to undisturbed communities. Our findings showed that, when combined, the two-stressor joint impacts changed from antagonistic to additive with increased recovery time between stressors. Surprisingly, full compositional recovery was not achieved despite a recovery period that was long enough for population growth, suggesting legacy effects from earlier treatment. The recovery was mainly driven by small organisms, such as rotifers and small cladocerans. As a result, communities recovering from previous salt exposure responded differently to heatwaves than undisturbed communities, leading to similar zooplankton communities regardless of the recovery time between stressors. Our research bolsters the understanding and management of multiple-stressor issues by revealing that prior exposure to one stressor has long-lasting impacts on community recovery that can lead to unexpected joint effects of multiple stressors.

Salinity decline promotes growth and harmful blooms of a toxic alga by diverting carbon flow.

Global climate change intensifies the water cycle and makes freshest waters become fresher and vice-versa. But how this change impacts phytoplankton in coastal, particularly harmful algal blooms (HABs), remains poorly understood. Here, we monitored a coastal bay for a decade and found a significant correlation between salinity decline and the increase of Karenia mikimotoi blooms. To examine the physiological linkage between salinity decreases and K. mikimotoi blooms, we compare chemical, physiological and multi-omic profiles of this species in laboratory cultures under high (33) and low (25) salinities. Under low salinity, photosynthetic efficiency and capacity as well as growth rate and cellular protein content were significantly higher than that under high salinity. More strikingly, the omics data show that low salinity activated the glyoxylate shunt to bypass the decarboxylation reaction in the tricarboxylic acid cycle, hence redirecting carbon from CO2 release to biosynthesis. Furthermore, the enhanced glyoxylate cycle could promote hydrogen peroxide metabolism, consistent with the detected decrease in reactive oxygen species. These findings suggest that salinity declines can reprogram metabolism to enhance cell proliferation, thus promoting bloom formation in HAB species like K. mikimotoi, which has important ecological implications for future climate-driven salinity declines in the coastal ocean with respect to HAB outbreaks.

Future carbon sequestration potential in a widespread transcontinental boreal tree species: Standing genetic variation matters!

Climate change (CC) necessitates reforestation/afforestation programs to mitigate its impacts and maximize carbon sequestration. But comprehending how tree growth, a proxy for fitness and resilience, responds to CC is critical to maximize these programs' effectiveness. Variability in tree response to CC across populations can notably be influenced by the standing genetic variation encompassing both neutral and adaptive genetic diversity. Here, a framework is proposed to assess tree growth potential at the population scale while accounting for standing genetic variation. We applied this framework to black spruce (BS, Picea mariana [Mill] B.S.P.), with the objectives to (1) determine the key climate variables having impacted BS growth response from 1974 to 2019, (2) examine the relative roles of local adaptation and the phylogeographic structure in this response, and (3) project BS growth under two Shared Socioeconomic Pathways while taking standing genetic variation into account. We modeled growth using a machine learning algorithm trained with dendroecological and genetic data obtained from over 2600 trees (62 populations divided in three genetic clusters) in four 48-year-old common gardens, and simulated growth until year 2100 at the common garden locations. Our study revealed that high summer and autumn temperatures negatively impacted BS growth. As a consequence of warming, this species is projected to experience a decline in growth by the end of the century, suggesting maladaptation to anticipated CC and a potential threat to its carbon sequestration capacity. This being said, we observed a clear difference in response to CC within and among genetic clusters, with the western cluster being more impacted than the central and eastern clusters. Our results show that intraspecific genetic variation, notably associated with the phylogeographic structure, must be considered when estimating the response of widespread species to CC.

A manifesto for coastal landscape governance: Reframing the relationship between coastal and landscape governance.

There is an urgent demand for substantial reforms in the governance of coastal regions. Recent research advocates for a transformative shift in European coastal governance system towards a landscape governance approach. This perspective, informed by a narrative literature review on coastal and landscape governance, explores the potential value of coastal landscape governance, drawing on the Council of Europe Landscape Convention. Our results, presented in the form of a manifesto, underscore the need to move beyond political administrative boundaries and address all coastal landscapes as socio-ecological systems. It emphasises the necessity for the State to recognise them as a public and common good, establishing a specific governance arena with dedicated actors and institutions. The manifesto also advocates for landscape justice through knowledge co production, urging transformative change and landscape based regional design to envision alternative futures. Additionally, it calls for regionalising coastal landscape governance and invites scholars from other transdisciplinary and interdisciplinary perspectives to contribute to this research agenda.

A meta-analysis of probiotic interventions to mitigate ruminal methane emissions in cattle: implications for sustainable livestock farming.

In recent years, the significant impact of ruminants on methane emissions has garnered international attention. While dietary strategies have been implemented to solve this issue, probiotics gained the attention of researchers due to their sustainability. However, it is challenging to ascertain their effectiveness as an extensive range of strains and doses have been reported in the literature. Hence, the objective of this experiment was to perform a meta-analysis of probiotic interventions aiming to reduce ruminal methane emissions from cattle. From 362 articles retrieved from scientific databases, 85 articles were assessed independently by two reviewers, and 20 articles representing 49 comparisons were found eligible for meta-analysis. In each study, data such as mean, SD, and sample sizes of both the control and probiotic intervention groups were extracted. The outcomes of interest were methane emission, methane yield, and methane intensity. For the meta-analysis, effect sizes were pooled using a fixed effect or a random effect model depending on the heterogeneity. Afterward, sensitivity analyses were conducted to confirm the robustness of the findings. Overall pooled standardized mean differences (SMDs) with their confidence intervals (CIs) did not detect significant differences in methane emission (SMD = -0.04; 95% CI = -0.18-0.11; P = 0.632), methane yield (SMD = -0.08; 95% CI = -0.24-0.07; P = 0.291), and methane intensity (SMD = -0.22; 95% CI = -0.50-0.07; P = 0.129) between cattle supplemented with probiotics and the control group. However, subgroup analyses revealed that multiple-strain bacterial probiotics (SMD = -0.36; 95% CI = -0.62 to -0.11; P = 0.005), specifically the combination of bacteria involved in reductive acetogenesis and propionate production (SMD = -0.71; 95% CI = -1.04 to -0.36; P = 0.001), emerged as better interventions. Likewise, crossbreeds (SMD = -0.48; 95% CI = -0.78 to -0.18; P = 0.001) exhibited a more favorable response to the treatments. Furthermore, meta-regression demonstrated that longer periods of supplementation led to significant reductions in methane emissions (P = 0.001), yield (P = 0.032), and intensity (P = 0.012) effect sizes. Overall, the results of the current study suggest that cattle responses to probiotic interventions are highly dependent on the probiotic category. Therefore, extended trials performed with probiotics containing multiple bacterial strains are showing the most promising results. Ideally, further trials focusing on the use of probiotics to reduce ruminal methane in cattle should be conducted to complete the available literature.

Atmospheric Concentrations and Potential Sources of Dioxin-Like Contaminants to Acadia National Park.

Acadia National Park (ANP) is located on Mt. Desert Island, ME on the U.S. Atlantic coast. ANP is routinely a top-ten most popular National Park with over four million visits in 2022. The overall contribution and negative effects of long-range atmospheric transport and local sources of dioxin-like contaminants endangering natural and wildlife resources is unknown. Dioxin-like (DL) contaminants polychlorinated dibenzo-p-dioxins (∑PCDD) and polychlorinated dibenzofurans (∑PCDF), non-ortho coplanar PCBs (∑CP4), and polychlorinated naphthalenes (∑PCNs) were measured at the McFarland Hill air monitoring station (44.37°N, 68.26°W). On a mass/volume basis, total PCNs averaged 90.9 % (788 fg/m3) of DL contaminants measured annually, with 92.9 % of the collected total in the vapor-phase. Alternatively, total dioxin/furans (∑PCDD/Fs) represented 71.6 % of the total toxic equivalence (∑TEQ) (1.018 fg-TEQ/m3), with 69.7 % in the particulate-phase. Maximum concentrations measured for individual sampling events for ∑PCDD/F, ∑CP4, and ∑PCN were 159 (winter), 139 (summer), and 2100 (autumn), fg/m3 respectively. Whereas the maximum ∑TEQ concentrations for individual sampling events for ∑PCDD/F, ∑CP4, and ∑PCN were 2.8 (autumn), 0.38 (summer), and 0.71 (autumn), fg-TEQ/m3 respectively. Pearson correlations were calculated for ∑PCDD/Fs and ∑PCN particulate/vapor-phase air concentrations and PM2.5 wood smoke "indicator" species. The most significant correlations were observed in autumn for particulate-phase ∑PCDD/Fs suggesting a relationship between visitation-generated combustion sources (campfires and/or waste burning) or climate-change mediated forest fires. Significant Clausius-Clapeyron (C-C) correlations observed for particulate-phase ∑PCDDs (r2=0.567) as ambient temperatures decreased suggests a connection between localized domestic heating sources or visitor-based burning of wood/trash resources. Alternatively, highly significant C-C vapor-phase ∑CP4-PCBs correlations (r2=0.815) implies that the majority of ∑CP4-PCB loading to ANP is from long-range atmospheric transport processes. Based on these findings, Acadia National Park should be classified as a remote site with minor depositional impacts from ∑PCDD/Fs, ∑CP4-PCBs, and ∑PCN atmospheric transport or local diffuse sources.

Key factors influencing Hg levels and trends in unperturbed oligotrophic temperate and boreal lakes.

Mercury (Hg) is a toxic metal that presents a major risk to ecosystems, biota, human health, and remains a priority concern. In temperate and boreal lakes Hg and methylmercury (MMHg) are expected to vary as a function of atmospheric Hg deposition, lake water chemistry, catchment characteristics and climate variables. The aim of this study was to quantify Hg and MMHg in unperturbed oligotrophic lakes and to identify the factors controlling their distribution. We first hypothesized that lake Hg (and MMHg to lesser extent) spatial variations are linked to atmospheric deposition, catchment characteristics, and terrestrial exportation of dissolved organic carbon (DOC). We secondly examined if lake Hg concentrations have followed the decrease in atmospheric Hg emission observed between the mid-1990s to the end-2010s. We found that overall, atmospheric Hg has little impact on lake Hg and MMHg concentrations, which are both primarily influenced by DOC input originating from the forest catchment. The relationship between DOC and Hg differed between the spring and the fall, with a Hg-to-DOC ratio twice as high in spring. This seems related to snowmelt input of Hg (with a relatively reduced input of DOC) or the internal lake build-up of Hg during the ice-covered period. Of the 10 lakes intensively visited over a 20-year period, only 3 showed significant lake Hg decreases despite significant negative trends in atmospheric Hg concentrations, suggesting a lag between atmospheric and surface water temporal trends. Overall, terrestrial catchments retain around 80% of atmospheric Hg implying that large Hg pools have been built up in soils in the last decades. As such, the reduction of atmospheric Hg alone will not necessarily result in Hg decreases in lakes, since the Hg concentrations may be modulated by DOC export trends and catchment characteristics. This stresses the need to improve our understanding of the processes governing Hg transfers from catchments into lakes.

A dynamic energy budget (DEB) model to assess the sublethal effects of imidacloprid toward Gammarus pulex at different temperatures.

Environmental ambient temperature significantly impacts the metabolic activities of aquatic ectotherm organisms and influences the fate of various chemicals. Although numerous studies have shown that the acute lethal toxicity of most chemicals increases with increasing temperature, the impact of temperature on chronic effects - encompassing both lethal and sublethal endpoints - has received limited attention. Furthermore, the mechanisms linking temperature and toxicity, potentially unveiled by toxicokinetic-toxicodynamic models (TKTD), remains inadequately explored. This study investigated the effects of environmentally relevant concentrations of the insecticide imidacloprid (IMI) on the growth and survival of the freshwater amphipod Gammarus pulex at two different temperatures. Our experimental design was tailored to fit a TKTD model, specifically the Dynamic Energy Budget (DEB) model. We conducted experiments spanning three and six months, utilizing small G. pulex juveniles. We observed effects endpoints at least five times, employing both destructive and non-destructive methods, crucial for accurate model fittings. Our findings reveal that IMI at environmental concentrations (up to 0.3 µg/L) affects the growth and survival of G. pulex, albeit with limited effects, showing a 10% inhibition compared to the control group. These limited effects, observed in both lethal and sublethal aspects, suggest a different mode of action at low, environmentally-relevant concentrations in long-term exposure (3 months), in contrast to previous studies which applied higher concentrations and found that sublethal effects occurred at significantly lower levels than lethal effects in an acute test setting (4 days). Moreover, after parameterizing the DEB model for various temperatures, we identified a lower threshold for both lethal and sublethal effects at higher temperatures, indicating increased intrinsic sensitivity. Overall, this study contributes to future risk assessments considering temperature as a crucial factor and exemplifies the integration of the DEB model into experimental design for comprehensive toxicity evaluations.

Re-assessing thermal response of schistosomiasis transmission risk: evidence for a higher thermal optimum than previously predicted.

The geographical range of schistosomiasis is affected by the ecology of schistosome parasites and their obligate host snails, including their response to temperature. Previous models predicted schistosomiasis' thermal optimum at 21.7 °C, which is not compatible with the temperature in sub-Saharan Africa (SSA) regions where schistosomiasis is hyperendemic. We performed an extensive literature search for empirical data on the effect of temperature on physiological and epidemiological parameters regulating the free-living stages of S. mansoni and S. haematobium and their obligate host snails, i.e., Biomphalaria spp. and Bulinus spp., respectively. We derived nonlinear thermal responses fitted on these data to parameterize a mechanistic, process-based model of schistosomiasis. We then re-cast the basic reproduction number and the prevalence of schistosome infection as functions of temperature. We found that the thermal optima for transmission of S. mansoni and S. haematobium range between 23.1-27.3 °C and 23.6-27.9 °C (95 % CI) respectively. We also found that the thermal optimum shifts toward higher temperatures as the human water contact rate increases with temperature. Our findings align with an extensive dataset of schistosomiasis prevalence in SSA. The refined nonlinear thermal-response model developed here suggests a more suitable current climate and a greater risk of increased transmission with future warming for more than half of the schistosomiasis suitable regions with mean annual temperature below the thermal optimum.

Can mixing Quercus robur and Quercus petraea with Pinus sylvestris compensate for productivity losses due to climate change?

The climate change scenarios RCP 4.5 and RCP 8.5, with a representative concentration pathway for stabilization of radiative forcing of 4.5 W m-2 and 8.5 W m-2 by 2100, respectively, predict an increase in temperature of 1-4.5° Celsius for Europe and a simultaneous shift in precipitation patterns leading to increased drought frequency and severity. The negative consequences of such changes on tree growth on dry sites or at the dry end of a tree species distribution are well-known, but rarely quantified across large gradients. In this study, the growth of Quercus robur and Quercus petraea (Q. spp.) and Pinus sylvestris in pure and mixed stands was predicted for a historical scenario and the two climate change scenarios RCP 4.5 and RCP 8.5 using the individual tree growth model PrognAus. Predictions were made along an ecological gradient ranging from current mean annual temperatures of 5.5-11.4 °C and with mean annual precipitation sums of 586-929 mm. Initial data for the simulation consisted of 23 triplets established in pure and mixed stands of Q. spp. and P. sylvestris. After doing the simulations until 2100, we fitted a linear mixed model using the predicted volume in the year 2100 as response variable to describe the general trends in the simulation results. Productivity decreased for both Q. spp. and P. sylvestris with increasing temperature, and more so, for the warmer sites of the gradient. P. sylvestris is the more productive tree species in the current climate scenario, but the competitive advantage shifts to Q. spp., which is capable to endure very high negative water potentials, for the more severe climate change scenario. The Q. spp.-P. sylvestris mixture presents an intermediate resilience to increased scenario severity. Enrichment of P. sylvestris stands by creating mixtures with Q. spp., but not the opposite, might be a right silvicultural adaptive strategy, especially at lower latitudes. Tree species mixing can only partly compensate productivity losses due to climate change. This may, however, be possible in combination with other silvicultural adaptation strategies, such as thinning and uneven-aged management.

Unravelling biochemical responses in the species Mytilus galloprovincialis exposed to the antineoplastics ifosfamide and cisplatin under different temperature scenarios.

This study investigates the chronic impact of two of the most widely consumed antineoplastic drugs, Ifosfamide (IF) and Cisplatin (CDDP), on the bivalve species Mytilus galloprovincialis under current (17 °C) and predicted warming conditions (21 °C). Accompanying the expected increase in worldwide cancer incidence, antineoplastics detection in the aquatic environment is also expected to rise. Mussels were exposed to varying concentrations of IF (10, 100, 500 ng/L) and CDDP (10, 100, 1000 ng/L) for 28 days. Biochemical analyses focused on metabolic capacity, antioxidant and biotransformation capacity, cellular damage, and neurotoxicity. Results showed temperature-dependent variations in biochemical responses. Metabolic capacity remained stable under IF, while CDDP exposure increased it at 1000 ng/L for both temperatures. Antioxidant enzyme activities were unaffected by IF, but CDDP activated them, particularly at 21 °C. Biotransformation capacity was unchanged by IF but enhanced by CDDP. Nevertheless, cellular damage occurred at CDDP concentrations above 100 ng/L, regardless of temperature. Integrated biomarker responses highlighted CDDP's greater impact, emphasizing the critical role of temperature in shaping organismal responses and underscoring the complexity of environmental stressor interactions.

Diverse responses of surface biogeophysical parameters to accelerated development and senescence of vegetation on the Mongolian Plateau.

Vegetation dynamics is essential for characterizing surface biogeophysical parameters. Speeds of vegetation development and senescence are well documented, however, the effects of vegetation growth rates on surface parameters during different growth stages remains unclear. By using such methods as trend analyses and correlation analyses, this study examines the variations and interactive relationships of leaf area index (LAI) and surface parameters including Albedo, evapotranspiration (ET), and land surface temperature (LST), derived from Moderate Resolution Imaging Spectroradiometer (MODIS), during the intra-growing season (April-October, GS) on the Mongolian Plateau (MP). Generally, LAI exhibited a significant upward trend across GS months. Significant changes in VLAI (the difference in LAI between 2 consecutive months) in April-May and September-October indicated that the vegetation change rates were accelerated in the early GS (April-June) and late GS (September-October). The effect of vegetation activity on surface parameters varies over time and space. The effects of VLAI on the speed of surface parameters were inconsistent during the intra-GS. As a result of the significant changes in LAI, VET (the difference in ET between 2 consecutive months) displayed a significant upward trend during the early GS but a significant downward trend during the late GS. With acceleration of vegetation activity, the effects of VET and VAlbedo (the difference in Albedo between 2 consecutive months) on LST could offset each other at different stages of the GS. In addition, the effect of VLAI on the speed of surface parameters varied significantly by vegetation types. Our findings imply that clarifying the impact of vegetation activity on surface parameters at different growth stages can advance our understanding of vegetation responses and feedbacks to climate change.

How tree traits modulate tree methane fluxes: A review.

Trees can play different roles in the regulation of fluxes of methane (CH4), a greenhouse gas with a warming potential 83 times greater than that of carbon dioxide. Forest soils have the greatest potential for methane uptake compared to other land uses. In addition to their influence on soil CH4 fluxes, trees can act directly as a source or sink of CH4, by transporting CH4 produced in the soil and harbouring the key microorganisms involved in CH4 production and consumption (methanogens and methanotrophs). Tree CH4 fluxes can vary between species characterized by different traits that influence transport and modify the availability of CH4 reaction substrates as well as the habitat for methanogens and methanotrophs. Despite their important role in modulating CH4 fluxes from forest ecosystems, the identity and role of tree traits influencing these fluxes are poorly consolidated in the literature. The objectives of this paper are to 1) Review the functional traits of trees associated with their role in the regulation of CH4 emissions; 2) Assess the importance of inter-specific variability in CH4 fluxes via a global analysis of tree methane fluxes in the literature. Our review highlights that differences in CH4 fluxes between tree species and individuals can be explained by a diversity of traits influencing CH4 transport and microbial production of CH4 such as wood density and secondary metabolites. We propose a functional classification for trees based on the key traits associated with a function in CH4 emissions. We identified the fast-growing species with low wood density, species adapted to flood and species vulnerable to rot as functional groups which can be net sources of CH4 in conditions favorable to CH4 production. The global analysis further demonstrated the importance of taxonomy, with other factors such as land type and season in explaining variability in tree CH4 fluxes.

Wildfire smoke impacts lake ecosystems.

Wildfire activity is increasing globally. The resulting smoke plumes can travel hundreds to thousands of kilometers, reflecting or scattering sunlight and depositing particles within ecosystems. Several key physical, chemical, and biological processes in lakes are controlled by factors affected by smoke. The spatial and temporal scales of lake exposure to smoke are extensive and under-recognized. We introduce the concept of the lake smoke-day, or the number of days any given lake is exposed to smoke in any given fire season, and quantify the total lake smoke-day exposure in North America from 2019 to 2021. Because smoke can be transported at continental to intercontinental scales, even regions that may not typically experience direct burning of landscapes by wildfire are at risk of smoke exposure. We found that 99.3% of North America was covered by smoke, affecting a total of 1,333,687 lakes ≥10 ha. An incredible 98.9% of lakes experienced at least 10 smoke-days a year, with 89.6% of lakes receiving over 30 lake smoke-days, and lakes in some regions experiencing up to 4 months of cumulative smoke-days. Herein we review the mechanisms through which smoke and ash can affect lakes by altering the amount and spectral composition of incoming solar radiation and depositing carbon, nutrients, or toxic compounds that could alter chemical conditions and impact biota. We develop a conceptual framework that synthesizes known and theoretical impacts of smoke on lakes to guide future research. Finally, we identify emerging research priorities that can help us better understand how lakes will be affected by smoke as wildfire activity increases due to climate change and other anthropogenic activities.

Mental models for inclusive, socially-just disaster planning: a multi-community study in Saint Martin after Hurricane Irma.

Local perspectives provide different insights into disaster planning and response as compared to those of experts. Eliciting them, however, can be challenging, particularly for marginalised groups whose viewpoints have historically been excluded from planning processes. Fuzzy cognitive mapping (FCM) provides a semi-quantitative approach to representing the collective understanding or 'mental models' of diverse individuals and communities. This study involved 23 FCM interviews across three neighbourhoods of Saint Martin to comprehend: (i) how individuals' mental models of Hurricane Irma (2017) differ based on their context; (ii) how aligned mental models are with policy and planning documents; and (iii) the implications for the inclusiveness and representativeness of disaster response policies. It found that the residents of different neighbourhoods provided unique insights into the factors driving the social-ecological system, and that official policies aligned closely with priorities. The paper argues that the inclusion of the perspectives of different groups in disaster recovery is essential for an equitable process.

Factors limiting the potential range expansion of lodgepole pine in Interior Alaska.

Understanding the factors influencing species range limits is increasingly crucial in anticipating migrations due to human-caused climate change. In the boreal biome, ongoing climate change and the associated increases in the rate, size, and severity of disturbances may alter the distributions of boreal tree species. Notably, Interior Alaska lacks native pine, a biogeographical anomaly that carries implications for ecosystem structure and function. The current range of lodgepole pine (Pinus contorta var. latifolia) in the adjacent Yukon Territory may expand into Interior Alaska, particularly with human assistance. Evaluating the potential for pine expansion in Alaska requires testing constraints on range limits such as dispersal limitations, environmental tolerance limits, and positive or negative biotic interactions. In this study, we used field experiments with pine seeds and transplanted seedlings, complemented by model simulations, to assess the abiotic and biotic factors influencing lodgepole pine seedling establishment and growth after fire in Interior Alaska. We found that pine could successfully recruit, survive, grow, and reproduce across our broadly distributed network of experimental sites. Our results show that both mammalian herbivory and competition from native tree species are unlikely to constrain pine growth and that environmental conditions commonly found in Interior Alaska fall well within the tolerance limits for pine. If dispersal constraints are released, lodgepole pine could have a geographically expansive range in Alaska, and once established, its growth is sufficient to support pine-dominated stands. Given the impacts of lodgepole pine on ecosystem processes such as increases in timber production, carbon sequestration, landscape flammability, and reduced forage quality, natural or human-assisted migration of this species is likely to substantially alter responses of Alaskan forest ecosystems to climate change.

Strong acclimation effect of temperature and humidity on heat tolerance of the Arctic collembolan Megaphorura arctica.

The Arctic is a highly variable environment in which extreme daily and seasonal temperature fluctuations can occur. With climate change, an increase in the occurrence of extreme high temperatures and drought events is expected. While the effects of cold and dehydration stress on polar arthropods are well studied in combination, little is known about how these species respond to the combined effects of heat and dehydration stress. In this paper we investigate how the heat tolerance of the Arctic collembola Megaphorura arctica is affected by combinations of different temperature and humidity acclimation regimes under controlled laboratory conditions. The effect of acclimation temperature was complex and highly dependent on both acclimation time and temperature, and was found to either have a positive, negative, or no effect depending on experimental conditions. Further, we found marked effects of the interaction between temperature and humidity on heat tolerance, with a lower humidity severely decreasing the heat tolerance when the acclimation temperature was increased. This effect was more pronounced with increasing acclimation time. Lastly, the effect of acclimation on heat tolerance under a fluctuating temperature regime was dependent on acclimation temperature and time, as well as humidity levels. Together these results show that thermal acclimation alone has moderate or no effect on heat tolerance, but that drought events, likely to be more frequent in the future, in combination with high temperature stress can have large negative impacts on heat tolerance of some Arctic arthropods.

Patterns and correlates of potential range shifts of bat species in China in the context of climate change.

Climate change may diminish biodiversity; thus, it is urgent to predict how species' ranges may shift in the future by integrating multiple factors involving more taxa. Bats are particularly sensitive to climate change due to their high surface-to-volume ratio. However, few studies have considered geographic variables associated with roost availability and even fewer have linked the distributions of bats to their thermoregulation and energy regulation traits. We used species distribution models to predict the potential distributions of 12 bat species in China under current and future greenhouse gas emission scenarios (SSP1-2.6 and SSP5-8.5) and examined factors that could affect species' range shifts, including climatic, geographic, habitat, and human activity variables and wing surface-to-mass ratio (S-MR). The results suggest that Ia io, Rhinolophus ferrumequinum, and Rhinolophus rex should be given the highest priority for conservation in future climate conservation strategies. Most species were predicted to move northward, except for I. io and R. rex, which moved southward. Temperature seasonality, distance to forest, and distance to karst or cave were the main environmental factors affecting the potential distributions of bats. We found significant relationships between S-MR and geographic distribution, current potential distribution, and future potential distribution in the 2050s. Our work highlights the importance of analyzing range shifts of species with multifactorial approaches, especially for species traits related to thermoregulation and energy regulation, to provide targeted conservation strategies.

Patrones y correlaciones de los cambios potenciales en la distribución de las especies de murciélago de China en el contexto del cambio climático Resumen El cambio climático puede disminuir la biodiversidad, por lo que es urgente pronosticar cómo puede cambiar en el futuro la distribución de las especies mediante la integración de múltiples factores que involucren a más taxones. Los murciélagos son particularmente sensibles al cambio climático debido a que tienen una gran proporción superficie­volumen. Sin embargo, hay pocos estudios que han considerado las variables asociadas con la disponibilidad de nidos y son todavía menos los que han conectado la distribución de los murciélagos con sus rasgos de termorregulación y regulación de energía. Usamos modelos de distribución de especies para pronosticar la distribución potencial de doce especies de murciélago en China bajo escenarios actuales y futuros de emisión de gases de efecto invernadero (SSP1­2.6 y SSP5­8.5) y analizamos los factores que podrían afectar el cambio en la distribución de las especies, incluyendo las variables climáticas, geográficas, de hábitat y de actividad humana y la proporción entre la superficie del ala y la masa (P S­M). Los resultados sugieren que Ia io, Rhinolophus ferrumequinum y R. rex deberían ser la mayor prioridad de conservación para las estrategias de conservación climáticas en el futuro. Pronosticamos que la mayoría de las especies se desplazarían al norte, a excepción de I. io y R. rex, que se desplazarían hacia el sur. Los principales factores que afectaron la distribución potencial de los murciélagos fueron la estacionalidad de la temperatura, la distancia al bosque y la distancia a la cueva o al karst. Encontramos una relación significativa entre la P S­M y la distribución geográfica, la distribución potencial actual y la distribución potencial para la década de 2050. Nuestra investigación destaca la importancia del análisis de los cambios de distribución de las especies con enfoques multifactoriales, especialmente para los rasgos de especie relacionados con la termorregulación y la regulación de energía, para proporcionar estrategias de conservación focalizadas.