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1. Thermal tolerance in the millipede Euryurus leachii Gray (Polydesmida: Euryuridae)

   https://doi.org/10.1093/aesa/saac010  

   Barnes, Lindsey A ; Lawhorn, Kane A ; Yanoviak, Stephen P ( June 2022 , Annals of the Entomological Society of America)

   Abstract Temperature extremes often limit animal distributions. Whereas some poikilotherms (e.g., winged insects) can escape local thermal extremes, many less vagile organisms (e.g., insect larvae and arthropods with limited dispersal ability) are at the mercy of local microenvironmental conditions. Here, we quantified the thermal tolerance of an abundant, endemic, Nearctic millipede (Euryurus leachii), and explored the effects of seasonality, mass, and sex on its critical thermal maxima (CTmax). We also measured the thermal microenvironments of dead wood representing different decay classes. Overall, the mean CTmax for this species was ca. 40.5°C. Mass and sex had no effect on millipede CTmax. However, the mean CTmax for millipedes collected in the fall was 0.6°C higher than for individuals collected in the spring. An exposed dry log representing one common microhabitat for E. leachii readily warmed to temperatures exceeding its CTmax. The results suggest that CTmax is a seasonally plastic trait in E. leachii and that microclimatic conditions potentially limit the local distribution of this species. With habitat fragmentation and climate change contributing to warmer temperatures in forested systems, understanding the responses of detritivores like E. leachii can help predict potential shifts in community composition and ecosystem processes. 

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2. Plant developmental stage influences responses of Pinus strobiformis seedlings to experimental warming

   https://doi.org/10.1002/pei3.10055  

   Moler, Ehren Reid Von ; Kolb, Thomas ; Brady, Anne ; Palmiero, Briana Nicole ; Wallace, Taylor Robert ; Waring, Kristen Marie ; Whipple, Amy Vaughn ( June 2021 , Plant-Environment Interactions)

   Seedling emergence, survival, morphological and physiological traits, and oxidative stress resistance of southwestern white pine (Pinus strobiformisEngelm.) were studied in response to warming treatments applied during embryogenesis, germination, and early seedling growth. Daytime air temperature surrounding cones in tree canopies was warmed by +2.1°C during embryo development. Resulting seeds and seedlings were assigned to three thermal regimes in growth chambers, with each regime separated by 4°C to encompass the wide range of temperatures observed over space and time across the species’ range, plus the effect of heat waves coupled with a high carbon emissions scenario of climate warming. The embryo warming treatment reduced percent seedling emergence in all germination and growth environments and reduced mortality of seedlings grown in the warmest environment. Warm thermal regimes during early seedling growth increased subsequent seedling resistance to oxidative stress and transpirational water use. Experimental warming during seed development, germination, and seedling growth affected seedling emergence and survival. Oxidative stress resistance, morphology, and water relations were affected only by warming imposed during germination and seedling growth. This work explores potential outcomes of climate warming on multiple dimensions of seedling performance and uniquely illustrates that plant responses to heat vary with plant developmental stage in addition to the magnitude of temperature change.

    

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3. Lower thermal limits to larval development do not predict poleward range limits of the introduced tropical barnacle Megabalanus coccopoma

   https://doi.org/10.1111/ivb.12160  

   Crickenberger, Sam ; Walther, Kathleen ; Moran, Amy L. ( March 2017 , Invertebrate Biology)

   As the earth's climate has warmed, many tropical species have expanded their ranges poleward and encountered high‐latitude seasonal temperature regimes, in which further permanent expansion is limited by physiological vulnerability to cold temperatures. The barnacleMegabalanus coccopomais native to shorelines from Baja California to Peru and has been introduced to many locations worldwide, including the southeasternUSA. The ability of larvae to develop successfully at local temperatures can be an important factor limiting the spread of invasive species. To determine if cold temperatures limited larval success near the northern range limit ofM. coccopomaalong the Atlantic southeasternUSAcoast, we measured lower temperature limits to larval development, examined the effects of temperature on larval growth and energy accumulation, and calculated a larval energy budget to estimate the extent of potential larval dispersal in this region. Larvae were able to develop through metamorphosis at 16°C, which is much colder than sea surface temperatures during the spawning season in their invasive range, making it unlikely northern range limits are set by a lower temperature limit to larval development. Energy budgets suggest that for larvae produced at the northern end of the invasive range, long distance dispersal to sites far poleward of the current range limit is possible. Similar to the findings of the handful of other studies on cold tolerances of tropical marine invertebrate larvae, larvae should be successful far poleward of current adult distributions.

    

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4. Phenological and fitness responses to climate warming depend upon genotype and competitive neighbourhood in Arabidopsis thaliana

   https://doi.org/10.1111/1365-2435.13262  

   Taylor, Mark A. ; Cooper, Martha D. ; Schmitt, Johanna ; Manzaneda, ed., Antonio J. ( January 2019 , Functional Ecology)

   Increasing temperatures during climate change are known to alter the phenology across diverse plant taxa, but the evolutionary outcomes of these shifts are poorly understood. Moreover, plant temperature‐sensing pathways are known to interact with competition‐sensing pathways, yet there remains little experimental evidence for how genotypes varying in temperature responsiveness react to warming in realistic competitive settings.

   We compared flowering time and fitness responses to warming and competition for two near‐isogenic lines (NILs) ofArabidopsis thalianatransgressively segregating temperature‐sensitive and temperature‐insensitive alleles for major‐effect flowering time genes. We grew focal plants of each genotype in intraspecific and interspecific competition in four treatments contrasting daily temperature profiles in summer and fall under contemporary and warmed conditions. We measured phenology and fitness of focal plants to quantify plastic responses to season, temperature and competition and the dependence of these responses on flowering time genotype.

   The temperature‐insensitive NIL was constitutively early flowering and less fit, except in a future‐summer climate in which its fitness was higher than the later flowering, temperature‐sensitive NIL in low competition. The late‐flowering NIL showed accelerated flowering in response to intragenotypic competition and to increased temperature in the summer but delayed flowering in the fall. However, its fitness fell with rising temperatures in both seasons, and in the fall its marginal fitness gain from decreasing competition was diminished in the future.

   Functional alleles at temperature‐responsive genes were necessary for plastic responses to season, warming and competition. However, the plastic genotype was not the most fit in every experimental condition, becoming less fit than the temperature‐canalized genotype in the warm summer treatment.

   Climate change is often predicted to have deleterious effects on plant populations, and our results show how increased temperatures can act through genotype‐dependent phenology to decrease fitness. Furthermore, plasticity is not necessarily adaptive in rapidly changing environments since a nonplastic genotype proved fitter than a plastic genotype in a warming climate treatment.

   Aplain language summaryis available for this article.

    

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5. Climate Change Across Seasons Experiment (CCASE) at the Hubbard Brook Experimental Forest; concentrations of foliar metabolites: polyamines, amino acids, chlorophyll, carotenoids, soluble proteins, soluble elements, sugars, and total nitrogen and carbon in red maple (Acer rubrum) trees.

   https://doi.org/10.6073/pasta/f1c686538b00ca5a42f748dfe9ec2d0d  

   Minocha, Rakesh ; Blagden, Megan ; Harrison, Jamie L ; Sanders-DeMott, Rebecca ; Long, Stephanie ; Templer, Pamela H ( January 2021 , Environmental Data Initiative)

   Foliage was collected in 2015 and 2017 from red maple trees at the Climate Change Across Seasons Experiment (CCASE) as part of the Hubbard Brook Ecosystem Study (HBES). Analyses of foliar metabolites include polyamines, amino acids, chlorophylls, carotenoids, soluble proteins, soluble inorganic elements, sugars, and total nitrogen and carbon. There are six (11 x 14m) plots in total in this study; two control (plots 1 and 2), two warmed 5 degrees (°) Celsius (C) above ambient throughout the growing season (plots 3 and 4), and two warmed 5 °C in the growing season, with snow removal during the winter to induce soil freezing and then warmed with buried heating cables to create a subsequent thaw (plots 5 and 6). Each soil freeze/thaw cycle includes 72 hours of soil freezing followed by 72 hours of thaw. Four kilometers (km) of heating cable are buried in the soil to warm these four plots. Together, these treatments led to warmer growing season soil temperatures and an increased frequency of soil freeze-thaw cycles (FTCs) in winter. Our goal was to determine how these changes in soil temperature affect foliar nitrogen (N) and carbon metabolism of red maple trees. These data were gathered as a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. 

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