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1. Can extreme climatic events induce shifts in adaptive potential? A conceptual framework and empirical test with Anolis lizards

   https://doi.org/10.1111/jeb.14115  

   Simon, Monique N. ; Rothier, Priscila S. ; Donihue, Colin M. ; Herrel, Anthony ; Kolbe, Jason J. ( January 2023 , Journal of Evolutionary Biology)

   Multivariate adaptation to climatic shifts may be limited by trait integration that causes genetic variation to be low in the direction of selection. However, strong episodes of selection induced by extreme climatic pressures may facilitate future population-wide responses if selection reduces trait integration and increases adaptive potential (i.e., evolvability). We explain this counter-intuitive framework for extreme climatic events in which directional selection leads to increased evolvability and exemplify its use in a case study. We tested this hypothesis in two populations of the lizard Anolis scriptus that experienced hurricane-induced selection on limb traits. We surveyed populations immediately before and after the hurricane as well as the offspring of post-hurricane survivors, allowing us to estimate both selection and response to selection on key functional traits: forelimb length, hindlimb length, and toepad area. The direct selection was parallel in both islands and strong in several limb traits. Even though overall limb integration did not change after the hurricane, both populations showed a non-significant tendency toward increased evolvability after the hurricane despite the direction of selection not being aligned with the axis of most variance (i.e., body size). The population with comparably lower between-limb integration showed a less constrained response to selection. Hurricane-induced selection, not aligned with the pattern of high trait correlations, likely conflicts with selection occurring during normal ecological conditions that favours functional coordination between limb traits, and would likely need to be very strong and more persistent to elicit a greater change in trait integration and evolvability. Future tests of this hypothesis should use G-matrices in a variety of wild organisms experiencing selection due to extreme climatic events.

   Abstract

   We surveyed populations of A. scriptus lizards, in two islands, before the hurricane, after the hurricane (estimate of survivors) and the offspring almost two years later. We hypothesized that the direction of hurricane-induced selection would be to reduce between-limb trait correlations, resulting in higher variation in the direction of selection (higher evolvability). We found that selection had a similar direction in both populations, but was likely not strong or persistent enough to change trait correlations. However, the population with lower limb trait correlations showed a response to selection more aligned with the direction of selection. Finally, both populations showed a tendency to increase evolvability after the hurricane.

    

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2. Dietary shifts in a group of early Eocene euarchontans (Microsyopidae) in association with climatic change

   https://doi.org/10.1111/pala.12544  

   Selig, Keegan R. ; Chew, Amy E. ; Silcox, Mary T. ; Porro, ed., Laura ( June 2021 , Palaeontology)

   Microsyopidae is a family of plesiadapiforms known from over 1500 stratigraphically controlled specimens from the southern Bighorn Basin of Wyoming spanning the first three million years of the early Eocene. The early Eocene is characterized by rapid fluctuations in climate during the period represented by this collection of microsyopids, making this an ideal sample to examine how climate may have influenced early stem primate biology, particularly diet. An evolving lineage of microsyopids is known from before, during, and after Biohorizon A, a faunal turnover event associated with a period of localized cooling. Dental topographic analysis (DTA) metrics quantify functional aspects of molars including curvature, complexity and relief, and covary with diet in extant taxa. Here, we use DTA to examine microsyopid dietary change over time, particularly in association with this cooling event. Our results suggest that microsyopids had molars that are functionally like extant insectivorous/omnivorous euarchontans. The earliest occurring species,Arctodontomyswilsoni, is characterized by molars that became more like modern insectivores over time. During Biohorizon A,A. wilsoniis replaced byA. nuptus, which has molars that are more like those of extant omnivores with a mixed diet including fruit. After Biohorizon A,A. nuptusappears more insectivorous, as is the later occurringMicrosyopsangustidens, which evolves fromA. nuptus. Overall, we provide potential evidence for a causal scenario in which local climate change coincided with a dietary transition among microsyopids. Our results have implications for understanding how diet was a prime mover for the evolution of Primates.

    

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3. Shifts in functional traits and interactions patterns of soil methane‐cycling communities following forest‐to‐pasture conversion in the Amazon Basin

   https://doi.org/10.1111/mec.16912  

   Obregon Alvarez, Dasiel ; Fonseca de Souza, Leandro ; Mendes, Lucas William ; de Moraes, Moacir Tuzzin ; Tosi, Micaela ; Venturini, Andressa Monteiro ; Meyer, Kyle M. ; Barbosa de Camargo, Plínio ; Bohannan, Brendan J. M. ; Mazza Rodrigues, Jorge L. ; et al ( March 2023 , Molecular Ecology)
4. Methane, ethane, and propane production in Greenland ice core samples and a first isotopic characterization of excess methane

   https://doi.org/10.5194/cp-19-999-2023  

   Mühl, Michaela ; Schmitt, Jochen ; Seth, Barbara ; Lee, James E. ; Edwards, Jon S. ; Brook, Edward J. ; Blunier, Thomas ; Fischer, Hubertus ( January 2023 , Climate of the Past)

   Abstract. Air trapped in polar ice provides unique records of the pastatmospheric composition ranging from key greenhouse gases such as methane(CH4) to short-lived trace gases like ethane (C2H6) andpropane (C3H8). Recently, the comparison of CH4 recordsobtained using different extraction methods revealed disagreements in theCH4 concentration for the last glacial in Greenland ice. Elevatedmethane levels were detected in dust-rich ice core sections measureddiscretely, pointing to a process sensitive to the melt extraction technique. To shed light on the underlying mechanism, we performed targeted experiments and analyzed samples for methane and the short-chain alkanes ethane and propane covering the time interval from 12 to 42 kyr. Here, we report our findings of these elevated alkane concentrations, which scale linearly with the amount of mineral dust within the ice samples. The alkane production happens during the melt extraction step of the classic wet-extraction technique and reaches 14 to 91 ppb of CH4 excess in dusty ice samples. We document for the first time a co-production of excess methane, ethane, and propane, with the observed concentrations for ethane and propane exceeding their past atmospheric background at least by a factor of 10. Independent of the produced amounts, excess alkanes were produced in a fixed molar ratio of approximately 14:2:1, indicating a shared origin. The measured carbon isotopic signature of excess methane is (-47.0±2.9) ‰ and its deuterium isotopic signature is (-326±57) ‰. With the co-production ratios of excess alkanesand the isotopic composition of excess methane we established a fingerprintthat allows us to constrain potential formation processes. This fingerprintis not in line with a microbial origin. Moreover, an adsorption–desorptionprocess of thermogenic gas on dust particles transported to Greenlanddoes not appear very likely. Instead, the alkane pattern appears to beindicative of abiotic decomposition of organic matter as found in soils andplant leaves. 

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5. Climatic impact, future biomass production, and local adaptation of four switchgrass cultivars

   https://doi.org/10.1111/gcbb.12609  

   Zhang, Li ; Juenger, Thomas E. ; Lowry, David B. ; Behrman, Kathrine D. ( March 2019 , GCB Bioenergy)

   Previous studies have shown that switchgrass has a wide range of genetic variation and that productivity is linked to local adaptation to the location of origin for many cultivars. In this meta‐analysis, we compiled and analyzed 900 observations associated with 41 field trials for four switchgrass cultivars (two lowlands, Alamo and Kanlow, and two uplands, Cave‐In‐Rock and Shelter). This extensive dataset and machine learning were used to identify the most influential variables impacting switchgrass productivity, to search for evidence of local adaptation to each cultivar's location of origin, and to predict change in productivity under future climate for each cultivar. In general, variables associated with climate and management are more important predictors of productivity relative to soil variables. Three climatic variables, annual mean temperature, annual precipitation, and precipitation in the wettest month, are identified as key environmental variables for productivity of all cultivars. Productivity under future climate (2041–2060) is predicted to stay stable for all cultivars relative to the prediction under current climate (1986–2005) across all trial locations and over a 20‐year simulation period. However, the productivity of each cultivar varies from location to location and from year to year, although productivity varies more between locations than between years. Additionally, we observe shifts in the most productive cultivar at the local field scale depending on the combination of management practice and climates. The shape of the relationship between productivity and the annual mean temperature relative to the cultivar's location of origin is a bell‐shaped curve for Kanlow, Cave‐in‐Rock, and Shelter, indicative of local adaptation. Identifying influential environmental variables and their relationships to productivity with respect to cultivar's location of origin help predicting productivity on the local field scale, and will help with the biofuel production planning through the selection of suitable cultivars for different locations under climate changes.

    

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