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1. Relationship between local-scale topography and vegetation on the invasive C ₄ perennial bunchgrass buffelgrass ( Pennisetum ciliare ) size and reproduction

   https://doi.org/10.1017/inp.2023.9  

   Hovanes, Katherine A.; Lien, Aaron M.; Baldwin, Elizabeth; Li, Yue M.; Franklin, Kim; Gornish, Elise S. (March 2023, Invasive Plant Science and Management)

   Abstract Buffelgrass [Pennisetum ciliare(L.) Link] is an invasive C₄perennial bunchgrass that is a threat to biodiversity in aridlands in the Americas and Australia. Topography influencesP. ciliareoccurrence at large spatial scales, but further investigation into the relationship between local-scale topography andP. ciliaregrowth and reproduction would be beneficial. Further, density-dependent effects onP. ciliaregrowth and reproduction have been demonstrated in greenhouse experiments, but the extent to which density dependence influencesP. ciliarein natural populations warrants further investigation. Here we present a study on the relationships between local-scale topography (aspect and slope gradient) and vegetation characteristics (shrub cover,P. ciliarecover, andP. ciliaredensity) and their interactions on individualP. ciliareplant size and reproduction. We measured slope gradient, aspect, shrub cover,P. ciliarecover,P. ciliaredensity, and the total number of live culms and reproductive culms of 10P. ciliareplants in 33 4 by 4 m plots located in 11 transects at the Desert Laboratory at Tumamoc Hill, Tucson, AZ, USA. We modeled the relationships at the local scale of (1)P. ciliarecover and density with aspect and slope gradient and (2)P. ciliaresize and reproduction with abiotic (slope gradient and aspect) and biotic (P. ciliarecover and density and native shrub and cacti cover) characteristics. Aspect and slope gradient were poor predictors ofP. ciliarecover and density in already invaded sites at the scale of our plots. However, aspect had a significant relationship withP. ciliareplant size and reproduction.Pennisetum ciliareplants on south-facing aspects were larger and produced more reproductive culms than plants on other aspects. Further, we found no relationship betweenP. ciliaredensity andP. ciliareplant size and reproduction. Shrub cover was positively correlated withP. ciliarereproduction. South-facing aspects are likely most vulnerable to fast spread and infilling by newP. ciliareintroductions. 

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2. Laboratory Maintenance of the Chytrid Fungus Batrachochytrium dendrobatidis

   https://doi.org/10.1002/cpz1.309  

   Prostak, Sarah M.; Fritz‐Laylin, Lillian K. (December 2021, Current Protocols)

   Abstract The chytrid fungusBatrachochytrium dendrobatidis(Bd) is a causative agent of chytridiomycosis, a skin disease associated with amphibian population declines around the world. Despite the major impactBdis having on global ecosystems, much ofBd’s basic biology remains unstudied. In addition to revealing mechanisms driving the spread of chytridiomycosis, studyingBdcan shed light on the evolution of key fungal traits because chytrid fungi, includingBd, diverged before the radiation of the Dikaryotic fungi (multicellular fungi and yeast). StudyingBdin the laboratory is, therefore, of growing interest to a wide range of scientists, ranging from herpetologists and disease ecologists to molecular, cell, and evolutionary biologists. This protocol describes how to maintain developmentally synchronized liquid cultures ofBdfor use in the laboratory, how to growBdon solid media, as well as cryopreservation and revival of frozen stocks. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Reviving cryopreservedBdcultures Basic Protocol 2: Establishing synchronized liquid cultures ofBd Basic Protocol 3: Regular maintenance of synchronousBdin liquid culture Alternate Protocol 1: Regular maintenance of asynchronousBdin liquid culture Basic Protocol 4: Regular maintenance of synchronousBdon solid medium Alternate Protocol 2: Starting a culture on solid medium from a liquid culture Basic Protocol 5: Cryopreservation ofBd 

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3. Factors correlated with intracranial interictal epileptiform discharges in refractory epilepsy

   https://doi.org/10.1111/epi.16792  

   Quon, Robert_J; Meisenhelter, Stephen; Adamovich‐Zeitlin, Richard_H; Song, Yinchen; Steimel, Sarah_A; Camp, Edward_J; Testorf, Markus_E; MacKenzie, Todd_A; Gross, Robert_E; Lega, Bradley_C; et al (December 2020, Epilepsia)

   Abstract ObjectiveThis study was undertaken to evaluate the influence that subject‐specific factors have on intracranial interictal epileptiform discharge (IED) rates in persons with refractory epilepsy. MethodsOne hundred fifty subjects with intracranial electrodes performed multiple sessions of a free recall memory task; this standardized task controlled for subject attention levels. We utilized a dominance analysis to rank the importance of subject‐specific factors based on their relative influence on IED rates. Linear mixed‐effects models were employed to comprehensively examine factors with highly ranked importance. ResultsAntiseizure medication (ASM) status, time of testing, and seizure onset zone (SOZ) location were the highest‐ranking factors in terms of their impact on IED rates. The average IED rate of electrodes in SOZs was 34% higher than the average IED rate of electrodes outside of SOZs (non‐SOZ;p < .001). However, non‐SOZ electrodes had similar IED rates regardless of the subject's SOZ location (p = .99). Subjects on older generation (p < .001) and combined generation (p < .001) ASM regimens had significantly lower IED rates relative to the group taking no ASMs; newer generation ASM regimens demonstrated a nonsignificant association with IED rates (p = .13). Of the ASMs included in this study, the following ASMs were associated with significant reductions in IED rates: levetiracetam (p < .001), carbamazepine (p < .001), lacosamide (p = .03), zonisamide (p = .01), lamotrigine (p = .03), phenytoin (p = .03), and topiramate (p = .01). We observed a nonsignificant association between time of testing and IED rates (morning–afternoonp = .15, morning–eveningp = .85, afternoon–eveningp = .26). SignificanceThe current study ranks the relative influence that subject‐specific factors have on IED rates and highlights the importance of considering certain factors, such as SOZ location and ASM status, when analyzing IEDs for clinical or research purposes. 

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4. TOI-1696 and TOI-2136: Constraining the Masses of Two Mini-Neptunes with the Habitable-Zone Planet Finder

   https://doi.org/10.3847/1538-3881/ac69ec  

   Beard, Corey; Robertson, Paul; Kanodia, Shubham; Libby-Roberts, Jessica; Cañas, Caleb I.; Gupta, Arvind F.; Holcomb, Rae; Jones, Sinclaire; Kobulnicky, Henry A.; Lin, Andrea S. J.; et al (May 2022, The Astronomical Journal)

   Abstract We present the validation of two planets orbiting M dwarfs, TOI-1696b and TOI-2136b. Both planets are mini-Neptunes orbiting nearby stars, making them promising prospects for atmospheric characterization with the James Webb Space Telescope (JWST). We validated the planetary nature of both candidates using high-contrast imaging, ground-based photometry, and near-infrared radial velocities. Adaptive optics images were taken using the ShARCS camera on the 3 m Shane Telescope. Speckle images were taken using the NN-Explore Exoplanet Stellar Speckle Imager on the WIYN 3.5 m telescope. Radii and orbital ephemerides were refined using a combination of the Transiting Exoplanet Survey Satellite, the diffuser-assisted Astrophysical Research Consortium (ARC) Telescope Imaging Camera (ARCTIC) imager on the 3.5 m ARC telescope at Apache Point Observatory, and the 0.6 m telescope at Red Buttes Observatory. We obtained radial velocities using the Habitable-Zone Planet Finder on the 10 m Hobby–Eberly Telescope, which enabled us to place upper limits on the masses of both transiting planets. TOI-1696b (P= 2.5 days;R_p= 3.24R_⊕;M_p< 56.6M_⊕) falls into a sparsely populated region of parameter space considering its host star’s temperature (T_eff= 3168 K, M4.5), as planets of its size are quite rare around mid- to late-M dwarfs. On the other hand, TOI-2136b (P= 7.85 days;R_p= 2.09R_⊕;M_p< 15.0M_⊕) is an excellent candidate for atmospheric follow-up with the JWST. 

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5. Mechanistic links between biodiversity effects on ecosystem functioning and stability in a multi‐site grassland experiment

   https://doi.org/10.1111/1365-2745.13725  

   Yan, Ying; Connolly, John; Liang, Maowei; Jiang, Lin; Wang, Shaopeng (July 2021, Journal of Ecology)

   Abstract Although the positive effects of biodiversity on ecosystem functioning and stability have been extensively documented in the literature, previous studies have mostly explored the mechanisms of functioning and stability independently. It is unclear how biodiversity effects on functioning may covary with those on stability.Here we developed an integrated framework to explore links between mechanisms underlying biodiversity effects on functioning and those on stability. Specifically, biodiversity effects on ecosystem functioning were partitioned into complementarity effects (CE) and selection effects (SE), and those on stability were partitioned into species asynchrony and species stability. We investigated howCEandSEwere linked to species asynchrony and stability and how their links might be mediated by species evenness, using a multi‐site grassland experiment.Our mixed‐effects models showed that a higher community productivity was mainly due toCEand a higher community stability was mainly due to species asynchrony. Moreover,CEwas positively related to species asynchrony, thus leading to a positive association between ecosystem productivity and stability.We used a structural equation model to illustrate how species evenness might mediate links between the various mechanisms. Communities with a higher evenness exhibited a higherCEand species asynchrony, but a lowerSEand species stability. These evenness‐mediated associations enhanced the positive relationship betweenCEand species asynchrony, but blurred that betweenSEand species asynchrony.Synthesis. Our findings demonstrate mechanistic links between biodiversity effects on ecosystem functioning and stability. By doing so, our study contributes a novel framework for understanding ecological mechanisms of the functioning–stability relationship, which has important implications for developing management plans focused on strengthening synergies between ecosystem functioning and stability over the long term. 

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