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Background and Aims The sensitive fern, Onoclea sensibilis , is a widespread species in eastern North America and has an atypical timing of spore dispersal among temperate ferns. During early summer, this dimorphic species produces heavily modified spore-bearing fronds with leaflets tightly enveloping their sporangia and spores. These fronds senesce and persist above ground as dead mature structures until the following early spring when the leaflets finally open and spores are dispersed. While this timing of spore dispersal has been observed for over 120 years, the structural mechanisms underpinning this phenology have remained elusive. Methods Based on field observations, growth chamber manipulations and scanning electron microscopy, the mechanisms underlying this distinctive timing of spore dispersal in the sensitive fern were investigated. Key Results I show that fertile leaflets of the sensitive fern move in direct response to changes in humidity, exhibiting structural and functional parallels with multicellular hygromorphic structures in seed plants, such as pine cones. These parallels include differences in cellulose microfibril orientation in cells on the abaxial and adaxial sides of the leaflet. The dynamics of this hygroscopic movement concomitant with regular abscission zones along the pinnules and coordinated senescence lead to the specific timing of early spring spore dispersal in the sensitive fern. Conclusions While hygroscopic movement is common in seed-free plants, it mostly occurs in small structures that are either one or a few cells in size, such as the leptosporangium. Given its multicellular structure and integration across many cells and tissues, the movement and construction of the sensitive fern pinnules are more similar to structures in seed plants. The evolution of this complex trait in the sensitive fern efficiently regulates the timing of spore release, leading to early spring dispersal. This phenology likely gives gametophytes and subsequent sporophytes an advantage with early germination and growth. [ABSTRACT FROM AUTHOR]

Aim: Phenological mismatches, when life‐events become mistimed with optimal environmental conditions, have become increasingly common under climate change. Population‐level susceptibility to mismatches depends on how phenology and phenotypic plasticity vary across a species' distributional range. Here, we quantify the environmental drivers of colour moult phenology, phenotypic plasticity, and the extent of phenological mismatch in seasonal camouflage to assess vulnerability to mismatch in a common North American mammal. Location: North America. Time period: 2010–2017. Major taxa studied: Snowshoe hare (Lepus americanus). Methods: We used > 5,500 by‐catch photographs of snowshoe hares from 448 remote camera trap sites at three independent study areas. To quantify moult phenology and phenotypic plasticity, we used multinomial logistic regression models that incorporated geospatial and high‐resolution climate data. We estimated occurrence of camouflage mismatch between hares' coat colour and the presence and absence of snow over 7 years of monitoring. Results: Spatial and temporal variation in moult phenology depended on local climate conditions more so than on latitude. First, hares in colder, snowier areas moulted earlier in the fall and later in the spring. Next, hares exhibited phenotypic plasticity in moult phenology in response to annual variation in temperature and snow duration, especially in the spring. Finally, the occurrence of camouflage mismatch varied in space and time; white hares on dark, snowless background occurred primarily during low‐snow years in regions characterized by shallow, short‐lasting snowpack. Main conclusions: Long‐term climate and annual variation in snow and temperature determine coat colour moult phenology in snowshoe hares. In most areas, climate change leads to shorter snow seasons, but the occurrence of camouflage mismatch varies across the species' range. Our results underscore the population‐specific susceptibility to climate change‐induced stressors and the necessity to understand this variation to prioritize the populations most vulnerable under global environmental change. [ABSTRACT FROM AUTHOR]

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• Invasive plant management is highly variable, both in its application and outcome. • Long-term research on invasive plant management in forests is limited. • Improving native plant communities may require enrichment planting or seeding. • Disturbance facilitated by invasive plant control can lead to secondary invasion. • Silvicultural prescriptions should explicitly consider invasive plant control. Invasive plants can significantly impact the diversity of understory ground flora and forest regeneration in eastern North America. However, managing invasive plants has resulted in positive, negative, or neutral effects on key ecosystem components depending on treatment type, duration, and intensity. Management may also result in short-term control, but legacy effects from prior land use or secondary invasions may hamper desired long-term outcomes. We conducted a systematic review of the invasive plant management literature for eastern North American forests to examine treatment outcomes for invasive and native plants, tree regeneration, and secondary invasions. Our review included 165 articles with few papers published in the 1980s but the number of papers increasing through time thereafter. A variety of control methods were used, including herbicide applications, prescribed burning, torching, girdling, clipping, mastication, soil amendments, flooding, enrichment plantings, and biocontrol, as well as combinations of these treatments. Species included some of the most common forest invaders, such as the privets (Ligustrum spp.), honeysuckles (Lonicera spp.), autumn olive (Elaeagnus umbellata), buckthorns (Rhamnus cathartica and Frangula alnus), garlic mustard (Alliaria petiolata), Japanese stiltgrass (Microstegium vimineum), cogongrass (Imperata cylindrica), tree-of-heaven (Ailanthus altissima), and Chinese tallow (Triadica sebifera). The literature also included recent invaders in eastern North America, such as Callery pear (Pyrus calleryana) and fig buttercup (Ficaria verna). Findings suggest that invasive plant control efficacy is highly variable and context dependent. Information on long-term effects is limited because most studies reported on findings occurring within a few years of treatment. However, long-term success may be limited without additional management (e.g., enrichment plantings, artificial tree regeneration, re-establishing historic fire regimes, reducing herbivore densities) that ameliorates impacts from past land-use, disturbance history, or other factors. We suggest that future studies and the development of control tactics consider comprehensive approaches to building resilience in forest communities where invasive plants are only one aspect of the forest management continuum. [ABSTRACT FROM AUTHOR]

Objective To clarify whether the rate of decline in stimulated C-peptide ( SCP) from 2 to 15 months after diagnosis has changed over an interval of 27 yr. Research design and methods The rate of decline in SCP levels at 1, 2, 3, 6, 9, 12, and 15 months after diagnosis was compared in four paediatric cohorts from Scandinavian and European countries including 446 children with new onset type 1 diabetes ( T1D, 1982-2004). Findings were evaluated against 78 children (2004-2009) from the TrialNet studies. Results The mean rate of decline [%/month (± SEM)] in SCP for a 10-yr-old child was 7.7%/month (±1.5) in the 1982-1985 Cohort, 6.3%/month (±1.7) in the 1995-1998 Cohort, 7.8%/month (±0.7) in the 1999-2000 Cohort, and 10.7%/month (±0.9) in the latest 2004-2005 Cohort (p = 0.05). Including the TrialNet Cohort with a rate of decline in SCP of 10.0%/month (±0.9) the differences between the cohorts are still significant (p = 0.039). The rate of decline in SCP was negatively associated with age (p < 0.0001), insulin antibodies ( IA) (p = 0.003), and glutamic acid decarboxylase-65 ( GAD65A) (p = 0.03) initially with no statistically significant effect of body mass index ( BMI) Z-score at 3 months. Also, at 3 months the time around partial remission, the effect of age on SCP was significantly greater in children ≤5 yr compared with older children (p ≤ 0.0001). Conclusions During the past 27 yr, initial C-peptide as well as the rate of C-peptide decline seem to have increased. The rate of decline was affected significantly by age, GAD65A, and IA, but not BMI Z-score or initial C-peptide. [ABSTRACT FROM AUTHOR]

The article focuses on a study done in order to know changes in reproductive and survivorship parameters of Double-crested Cormorant, a seabird in Door County, Wisconsin. It mentions the methodology of the study which includes the banding of the birds at six islands of North America with butt-end leg bands and Program MARK, a software application for determining sighting probabilities. The study found significant increase in the banded birds' recovery every year of the study 1988 to 2005.

[Display omitted] • Hybridization and polyploidy are common in the investigated complex of Isoëtes from western North America. • Ploidy differences are not strong barriers to hybridization. • Directionality of hybridization events may be dictated by gamete size differences between diploids and polyploids. • Low reproductive barriers may facilitate the high levels of hybridization between co-occurring species. Polyploidy and hybridization are important processes in seed-free plant evolution. However, a major gap lies in our understanding of how these processes affect the evolutionary history of high-ploidy systems. The heterosporous lycophyte genus Isoëtes is a lineage with many putative hybrids and high-level polyploid taxa (ranging from tetraploid to dodecaploid). Here, we use a complex of western North American Isoëtes , to understand the role of hybridization and high-level polyploidy in generating and maintaining novel diversity. To uncover these processes, we use restriction-site associated DNA sequencing (RADseq), multiple alleles of a single low-copy nuclear marker, whole plastomes, cytology (genome size estimates and chromosome counts), and reproductive status (fertile or sterile). With this dataset, we show that hybridization occurs easily between species in this complex and is bidirectional between identical, but not different, cytotypes. Furthermore, we show that fertile allopolyploids appear to have formed repeatedly from sterile homoploid and interploid hybrids. We propose that low prezygotic reproductive barriers and a high frequency of whole-genome duplication allow for high-level polyploid systems to generate novel lineages, and that these mechanisms may be important in shaping extant Isoëtes diversity. [ABSTRACT FROM AUTHOR]

Much of what we know about terrestrial life during the Carboniferous Period comes from Middle Pennsylvanian (~315-307 Mya) Coal Measures deposited in low-lying wetland environments 1-5 . We know relatively little about terrestrial ecosystems from the Early Pennsylvanian, which was a critical interval for the diversification of insects, arachnids, tetrapods, and seed plants 6-10 . Here we report a diverse Early Pennsylvanian trace and body fossil Lagerstätte (~320-318 Mya) from the Wamsutta Formation of eastern North America, distinct from coal-bearing deposits, preserved in clastic substrates within basin margin conglomerates. The exceptionally preserved trace fossils and body fossils document a range of vertebrates, invertebrates and plant taxa (n = 131), with 83 distinct foliage morphotypes. Plant-insect interactions include what may be the earliest evidence of insect oviposition. This site expands our knowledge of early terrestrial ecosystems and organismal interactions and provides ground truth for future phylogenetic reconstructions of key plant, arthropod, and vertebrate groups., (© 2024. The Author(s).)