Wildfires are a significant agent of disturbance in forests and highly sensitive to climate change. Short-interval fires and high severity (mortality-causing) fires in particular, may catalyze rapid and substantial ecosystem shifts by eliminating woody species and triggering conversions from forest to shrub or grassland ecosystems. Modeling and fine-scale observations suggest negative feedbacks between fire and fuels should limit reburn prevalence as overall fire frequency rises. However, while we have good information on reburning patterns for individual fires or small regions, the validity of scaling these conclusions to broad regions like the US West remains unknown. Both the prevalence of reburning and the strength of feedbacks on likelihood of reburning over differing timescales have not been documented at the regional scale. Here we show that while there is a strong negative feedback for very short reburning intervals throughout wildland forests of the Western US, that feedback weakens after 10-20 years. The relationship between reburning intervals and drought diverges depending on location, with coastal systems reburning quicker (e.g. shorter interval between fires) in wetter conditions and interior forests in drier. This supports the idea that vegetation productivity-primarily fine fuels that accumulate rapidly (<10 years)-is of primary importance in determining reburn intervals. Our results demonstrate that while over short time intervals increasing fires inhibits reburning at broad scales, that breaks down after a decade. This provides important insights about patterns at very broad scales and agrees with finer scale work, suggesting that lessons from those scales apply across the entire western US.

Increasing rates of short-interval disturbances have the potential to rapidly transform ecosystems via shifts in post-disturbance regeneration. While research has explored compound events in multiple biomes, we know little regarding how local site conditions interact with short-interval disturbances to influence post-disturbance regeneration. Furthermore, questions remain regarding the consequences of continued high frequency events: What happens when emerging new communities are themselves subject to short-interval disturbances? To investigate effects of ongoing short-interval fires on regeneration, we examined post-fire forest regeneration in two locations in interior Alaska. We established 50 plots across a mosaic of fire histories (one, two, or three fires in <70 yr) in an upland and lowland site in interior Alaska. To investigate how shifts in community driven by short-interval fires differ according to local site conditions, we quantified abundance, proportion, and density of conifer and deciduous regeneration in a drier upland site and a wetter lowland site. Both sites were dominated by black spruce prior to burning. In the drier upland site, black spruce (Picea mariana) presence declined sharply after two fires, while paper birch (Betula neoalaskana) became increasingly abundant with each additional fire. In the wetter lowland site, less organic soil was consumed by fire and presence of black spruce persisted through an initial single reburn (two fires), indicating local topography may temporarily buffer reburning impacts. However, after three burns, conifers were effectively eliminated in both upland and lowland stands. Deciduous regeneration differed with site: Birch dominated in upland plots, while willow (Salix spp.) and aspen (Populus tremuloides) dominated in lowlands. These results offer strong empirical evidence of the divergence of boreal successional trajectories from previous historic norms. Furthermore, results from this study demonstrate shifts in post-fire succession in forested ecosystems continue to accumulate with additional short-interval disturbance events, overwhelming the interactive effects of local site conditions.

The coronavirus disease 2019 (COVID-19) pandemic is a disaster, defined as an event that suspends normal activities and threatens or causes severe, community-wide damage (Masten & Motti-Stefanidi, 2020). While all school children and their families have been impacted by COVID-19 to some degree, the burdens are disproportionately being borne by children experiencing poverty and children from minority racial and ethnic groups. In this article, we consider resilience and risk in the context of the COVID-19 pandemic by focusing on children's developing adaptive systems. When adaptive systems are functioning well, most children will demonstrate resilience to disaster. The capacity of children's adaptive systems to function well depends upon their developmental histories and the social and community resources available to them. We discuss how these factors contribute to children's adaptation and close with recommendations for communities looking to support resilience to the varied adversities of COVID-19. Impact and ImplicationsAll students are impacted by coronavirus disease 2019 (COVID-19) to some degree, but the impact is greater for children from disadvantaged groups like those experiencing poverty and from racial and ethnic minority groups. Resilience for students at risk is possible when they have the internal and external resources they need. This article describes how those resources develop and how broader communities and services can bolster resources to enable resilience for disadvantaged students in the context of COVID-19.

Harnessing the NEON data revolution to advance open environmental science with a diverse and data-capable community. Ecosphere 12(12):e03833.

Climate drivers are increasingly creating conditions conducive to higher frequency fires. In the coniferous boreal forest, the world’s largest terrestrial biome, fires are historically common but relatively infrequent. Post-fire, regenerating forests are generally resistant to burning (strong fire self-regulation), favoring millennial coniferous resilience. However, short intervals between fires are associated with rapid, threshold-like losses of resilience and changes to broadleaf or shrub communities, impacting carbon content, habitat, and other ecosystem services. Fires burning the same location 2 + times comprise approximately 4% of all Alaskan boreal fire events since 1984, and the fraction of short-interval events (< 20 years between fires) is increasing with time. While there is strong resistance to burning for the first decade after a fire, from 10 to 20 years post-fire resistance appears to decline. Reburning is biased towards coniferous forests and in areas with seasonally variable precipitation, and that proportion appears to be increasing with time, suggesting continued forest shifts as changing climatic drivers overwhelm the resistance of early postfire landscapes to reburning. As area burned in large fire years of ~ 15 years ago begin to mature, there is potential for more widespread shifts, which should be evaluated closely to understand finer grained patterns within this regional trend.

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

The combination of continuing anthropogenic impact on ecosystems across the globe and the observation of catastrophic shifts in some systems has generated substantial interest in understanding and predicting ecological tipping points. The recent establishment and full operation of NEON has created an

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