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Wild Pollinators Enhance Fruit Set of Crops Regardless of Honey Bee Abundance
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The diversity and abundance of wild insect pollinators have declined in many agricultural landscapes. Whether such declines reduce crop yields, or are mitigated by managed pollinators such as honey bees, is unclear. We found universally positive associations of fruit set with flower visitation by wild insects in 41 crop systems worldwide. In contrast, fruit set increased significantly with flower visitation by honey bees in only 14% of the systems surveyed. Overall, wild insects pollinated crops more effectively; an increase in wild insect visitation enhanced fruit set by twice as much as an equivalent increase in honey bee visitation. Visitation by wild insects and honey bees promoted fruit set independently, so pollination by managed honey bees supplemented, rather than substituted for, pollination by wild insects. Our results suggest that new practices for integrated management of both honey bees and diverse wild insect assemblages will enhance global crop yields.
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Wilderness and biodiversity conservation
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Human pressure threatens many species and ecosystems, so con- servation efforts necessarily prioritize saving them. However, conservation should clearly be proactive wherever possible. In this article, we assess the biodiversity conservation value, and specif- ically the irreplaceability in terms of species endemism, of those of the planet’s ecosystems that remain intact. We find that 24 wil- derness areas, all >1 million hectares, are >70% intact and have human densities of less than or equal to five people per km2. This wilderness covers 44% of all land but is inhabited by only 3% of people. Given this sparse population, wilderness conservation is cost-effective, especially if ecosystem service value is incorporated. Soberingly, however, most wilderness is not speciose: only 18% of plants and 10% of terrestrial vertebrates are endemic to individual wildernesses, the majority restricted to Amazonia, Congo, New Guinea, the Miombo–Mopane woodlands, and the North American deserts. Global conservation strategy must target these five wil- dernesses while continuing to prioritize threatened biodiversity hotspots.
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Wildfire
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Wildfire and forest harvest disturbances in the boreal forest leave different long-lasting spatial signatures
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Natural disturbances leave long-term legacies that vary among landscapes and ecosystem types, and which become integral parts of successional pro- cesses at a given location. As humans change land use, not only are immediate post-disturbance patterns altered, but the processes of recovery themselves are likely altered by the disturbance. We assessed whether short-term effects on soil and vegetation that distinguish wildfire from forest harvest persist over 60 years after disturbance in boreal black spruce forests, or post-disturbance processes of recovery promote convergence of the two disturbance types.
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Wildfire and fuel treatment effects on forest carbon dynamics in the western United States
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Sequestration of carbon (C) in forests has the potential to mitigate the effects of climate change by offsetting
future emissions of greenhouse gases. However, in dry temperate forests, wildfire is a natural disturbance
agent with the potential to release large fluxes of C into the atmosphere. Climate-driven
increases in wildfire extent and severity are expected to increase the risks of reversal to C stores and
affect the potential of dry forests to sequester C. In the western United States, fuel treatments that
successfully reduce surface fuels in dry forests can mitigate the spread and severity of wildfire, while
reducing both tree mortality and emissions from wildfire. However, heterogeneous burn environments,
site-specific variability in post-fire ecosystem response, and uncertainty in future fire frequency and
extent complicate assessments of long-term (decades to centuries) C dynamics across large landscapes.
Results of studies on the effects of fuel treatments and wildfires on long-term C retention across large
landscapes are limited and equivocal. Stand-scale studies, empirical and modeled, describe a wide range
of total treatment costs (12–116 Mg C ha1
) and reductions in wildfire emissions between treated and
untreated stands (1–40 Mg C ha1
). Conclusions suggest the direction (source, sink) and magnitude of
net C effects from fuel treatments are similarly variable (33 Mg C ha1 to +3 Mg C ha1
). Studies at large
spatial and temporal scales suggest that there is a low likelihood of high-severity wildfire events interacting
with treated forests, negating any expected C benefit from fuels reduction. The frequency, extent,
and severity of wildfire are expected to increase as a result of changing climate, and additional information
on C response to management and disturbance scenarios is needed improve the accuracy and usefulness
of assessments of fuel treatment and wildfire effects on C dynamics.
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Wildfire Collection
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The Southeast leads the nation in the number of annual wildland fire events but also has more prescribed (planned) burns than any other region. While fire has long played a critical role in the landscapes across the Southeast, it is becoming increasingly difficult for agencies, organizations, and landowners to plan for and respond effectively to wildfire, while protecting vulnerable communities and providing for firefighter safety.
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Wildfire Multimedia
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Wildfire Multimedia
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Wildfire Podcasts
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Wildfire Multimedia
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Wildfire Podcasts
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Wildfire Multimedia
