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Fire suppression has increased fuel load and the risk of catastrophic wildfire in forest and woodland ecosystems across the Western United States. In an effort to reduce fuel load and restore historical structure and function, land managers have implemented fuel reduction treatments on millions of acres. Reducing fuel loads protects people, structures, and in some cases, improves ecosystem health. However, the ecological risks of soil surface disturbance related to fuel reduction strategies, and subsequent soil erosion, may be significant in some cases. Here, we examined the effects of common fuel reduction strategies (mechanical mastication and two techniques for prescribed burning) on wind and water erosion in two upland pinon-juniper woodlands in SE Utah over 2 years. We also tested the impact of broadcast seeding coupled with fuel reduction as a way to mitigate erosional soil loss. Finally, we analyzed biotic and abiotic predictor variables to evaluate important drivers of soil erosion following fuel treatments. We found that both techniques for prescribed burning—pile burning and broadcast burning—increased wind-related sediment fluxes by an average of 11-fold and 58-fold, respectively. Mastication did not increase wind-related losses over untreated controls. Erosional fluxes measured at silt fences, that captured both wind- and water-driven sediments, followed similar trends with moderate increases from pile burning (fivefold) but larger increases from broadcast burning (17-fold). Seeding did not affect erosion rates. Our results suggest that prescribed fire significantly increases soil erosion in fuel-treated pinon-juniper woodlands and may be a degradation pathway when implementing treatments.

Extreme droughts, heat waves, fires, hurricanes, floods, and landslides cause the largest losses in the United States, and globally, from natural hazards linked to weather and climate. There is evidence that the frequency of such extremes is increasing, particularly for heat waves, large fires, and intense precipitation, making better understanding of the probability and consequences of these events imperative. Further, these events are not isolated, but rather interact with each other, and with social and ecological vulnerability, to amplify impacts. Less is known about the nature and strength of these interactions. Natural and social science subfields frame extreme events with different definitions and analytical approaches, and most analyses neglect interactions and the subsequent novel extremes that can arise. Here we propose a framework for socio-environmental extremes, defined as extraordinary events that emerge from interactions among biophysical and social phenomena and have some degree of social impact. We review how different fields approach extremes as interacting phenomena and propose a synthetic framework for conceptualizing and defining extremes from both an environmental and social perspective. This approach recognizes multiple drivers and responses that yield extreme events and extreme outcomes, and reconciles the gap between understanding extremes as biophysical processes and their social underpinnings and impacts. We conclude with a future research agenda that adds clarity and direction to understanding the extreme events that matter to society. This agenda will help to identify where, when, and why communities may have high exposure and vulnerability to socio- environmental extremes—informing future mitigation and adaptation strategies.

1. Platyprepia virginalis caterpillars are dietary generalists and feed on multiple host species within a single day. We conducted field experiments to evaluate their performance on diets consisting of only their primary food, Lupinus arboreus, or diets consisting of L. arboreus plus other acceptable host species. 2. We found that relative growth rates and rates of survival were higher when they fed on mixed diets compared to lupine only. These results were consistent with hypotheses that mixed diets provided balanced nutrition, diluted toxins, and/or allowed recovery from parasitoids, although our data did not allow us to separate these non-exclusive explanations. 3. We assayed alkaloids in their host foliage, in the caterpillars themselves, in parasitoids within caterpillars, in food boluses passing through their guts, and in frass that they excreted. We consistently found positive assays for alkaloids in foliage and in frass but negative assays in caterpillars, parasitoids, and food boluses. This suggests that the alkaloids that they ingest are metabolised or rendered non-reactive by unknown means during passage through the gut. We found no support for the hypothesis that mixed diets prevented caterpillars from exhausting food supplies or allowed them to sequester chemicals from their alkaloid-containing hosts. 4. Behavioural observations revealed that previous experience influenced a caterpillar's likelihood of moving to a different host. Caterpillars that had previously fed on other hosts were more likely to move to lupine while caterpillars previously collected on lupine were equally likely to choose more lupine or a different host. 5. These results are unusual in providing a clear and consistent benefit of diet mixing in a natural field setting where multiple ecological factors act upon the caterpillars.

Mountain beavers cache plants in neat piles above the ground near the entrances to their underground burrows, although the purpose of these hay piles remains controversial. We tested the hypothesis that drying plants in piles above ground may slow decay when the plants are stored underground. Predried plants and undried controls were placed in abandoned burrows. Plants that had been predried retained more green and decayed more slowly than undried controls. This experimental test supports the hypothesis that haying may extend the time during which plants are useful to mountain beavers.