Treesearch

Context: Consistent with the diversity-stability hypothesis, high wildlife diversity has been associated with increased resilience and stability of ecosystem services and functions. Nevertheless, ecological non-stationarity associated with climate change challenges the concept of stability. Furthermore, ambiguity surrounding appropriate diversity metrics to usehas hindered the ability of natural resource managers to leverage the potential benefits of biodiversity conservation.Objectives and methods: We aimed to infer how diversity and compositional stability might be affected by multiple...

Whitebark pine, a geographically widespread upper subalpine tree species, exists largely within federally designated Wilderness areas (herein, wilderness) that are afforded greater protection from direct human manipulation as compared to surrounding public and privately owned lands. Nevertheless, climate change, associated disturbances, historical fire suppression, disease, and other factors are causing an increase in tree mortality of this federally threatened foundation species in parts of its range. The 1964 Wilderness Act mandates that wilderness areas are preserved in their “natural”...

Adaptive evolution requires both natural selection and genetic variation. In introduced species, the selective dynamics of range expansion are predicted by theory to lead to differences between the core and the leading edge, with edge individuals evolving to be more fecund (under r-selection) and have greater dispersal ability than core individuals. In arthropods, both fecundity and dispersal ability are often positively correlated with body size. Here, we quantify genetic variation available for evolution of body size in a beetle (Diorhabda carinulata) introduced into North America as a...

Reports from western U.S. firefighters that nighttime fire activity has been increasing during the spans of many of their careers have recently been confirmed by satellite measurements over the 2003–20 period. The hypothesis that increasing nighttime fire activity has been caused by increased nighttime vapor pressure deficit (VPD) is consistent with recent documentation of positive, 40-yr trends in nighttime VPD over the western United States. However, other meteorological conditions such as near-surface wind speed and planetary boundary layer depth also impact fire behavior and exhibit...

Soils are the largest terrestrial carbon sink on Earth, yet substantial uncertainty in the size and stability of this pool remains. Much of this uncertainty stems from the characterization of bulk density, which is the mass of a soil sample divided by its volume, a key property in the calculation of soil organic carbon (SOC) stocks. We used data from nearly 2900 plots in the United States (U.S.) Nationwide Forest Inventory to quantify SOC stocks in forests with three common methods of calculating soil bulk density. Mean SOC stocks calculated with these methods varied by up to 13 Mg ha− 1,...

The July 2016 flood in northwest Wisconsin caused the failure of over 40 road-stream crossings and damaged 300 miles of roads on the Chequamegon-Nicolet National Forest. Peak flood flow estimates were obtained at 26 road-stream crossing sites including 17 sites designed using stream simulation (SS). Peak flood magnitudes ranged from 9 to 2,629 cubic feet/second/square mile (cfsm). Floods at 21 sites were over 100 cfsm which were 1.4 to 14.4 times greater than the estimated 1 percent annual exceedance probability flood. Only 1 of 17 SS sites failed, although 13 overtopped. Infrastructure...

The U.S. Department of Agriculture, Forest Service, National Best Management Practices (BMP) program assists in meeting agency Clean Water Act objectives with nationally consistent monitoring. National BMP program monitoring protocols are used to evaluate BMP implementation (including planning) and effectiveness for most types of land disturbing activities that occur on national forests and grasslands. This report summarizes data from the first two full monitoring periods—federal fiscal years 2015–2016 and 2017–2018—for range, road, and mechanical vegetation management protocols. Best...

The U.S. Department of Agriculture, Forest Service, National Best Management Practices (BMP) program assists in meeting agency Clean Water Act objectives with nationally consistent monitoring. National BMP program monitoring protocols are used to evaluate BMP implementation (including planning) and effectiveness for most types of land disturbing activities that occur on national forests and grasslands. This report summarizes data from the first two full monitoring periods—federal fiscal years 2015–2016 and 2017–2018—for wildland fire, recreation, and water uses management protocols. Best...

Nature-based solutions (NBS) are increasingly used to build urban climate resilience by employing natural features and processes. Implementing NBS in urban residential areas relies on the availability of unsealed soil surfaces. Here we investigate how soil is distributed at fine spatial scales across Los Angeles County, the second largest metropolitan area in the United States, to examine the potential for NBS to be realized equitably. We delineate soil patches in residential areas across a range of socioeconomic settings and urban forms, and then compare soil patch metrics to social...

Traits enabling fire tolerance are essential for plant persistence in fire-prone ecosystems. Yet, fire tolerance alone fails to account for other pre-existing forms of stress that could modify species tolerance of fire. Shade is an increasingly important form of stress on the contemporary forested landscape, as widespread fire exclusion has hastened the transition of many open woodlands into closed canopy forests. To investigate the interaction of fire and shade in the longleaf pine ecosystem, we established a shade house experiment examining seedling mortality and recovery of six native...