Treesearch

The northern Lake Huron shoreline in Michigan's Upper Peninsula has a largely east west orientation, extending from St. Ignace eastward to DeTour Village and then to neighboring Drummond Island (Fig. 1). Given this orientation, this shoreline intercepts large numbers of spring migrating birds after they fly across Lake Huron. These birds need to rest and refuel. For many of the insectivorous passerines or perching birds such as warblers (Fig. 2), vireos, and thrushes, they often arrive before the hardwood trees have fully leafed out and thus there are relatively few terrestrial insects...

Understanding why diversity sometimes limits disease is essential for managing outbreaks; however, mechanisms underlying this ‘dilution effect’ remain poorly understood. Negative diversity-disease relationships have previously been detected in plant communities impacted by an emerging forest disease, sudden oak death. We used this focal system to empirically evaluate whether these relationships were driven by dilution mechanisms that reduce transmission risk for individuals or from the fact that disease was averaged across the host community. We integrated laboratory competence measurements...

We investigated changes in soil chemistry and foliar metabolism of Himalayan cedar [Cedrus deodara (Roxb. Ex Lamb.) G.Don] and Himalayan spruce [Picea smithiana (Wall.) Boiss] trees along a steep elevational gradient in the lower Himalayan Mountains at Kufri, Himachal Pradesh (HP), India. The foliar and soil samples were collected from four locations along a 300 m elevational gradient at ridge, high-, mid-, and low-elevation sites within the forested ShimlaWater CatchmentWildlife Sanctuary that provides water for the city of Shimla, HP,. Observations at the time of sampling revealed that...

This is 1 of 23 guides to help Southeastern U.S. producers of economically important agricultural commodities build resilience to, prepare for, and recover from hurricane impacts. All guides can be found on the USDA Southeast Climate Hub Hurricane Preparation and Recovery Commodity Guides website.

Ecological forecasts will be best suited to inform intervention strategies if they are accessible to a diversity of decision-makers. Researchers are developing intuitive forecasting interfaces to guide stakeholders through the development of intervention strategies and visualization of results. Yet, few studies to date have evaluated how user interface design facilitates the coordinated, cross-boundary management required for controlling biological invasions. We used a participatory approach to develop complementary tangible and online interfaces for collaboratively forecasting biological...

The U.S. Forest Service is reconsidering policies that limit the size of trees that can be removed in the course of restoration treatments in dry forests of eastern Oregon. To evaluate the effects of diameter limits on the ability of managers to meet restoration objectives, we used an existing network of long-term research plots to summarize historical and contemporary structure and composition of mixed-conifer forests within a one million-ha study area in eastern Oregon. Then, we used a novel thinning simulation procedure to quantify the degree to which thinning using different diameter...

Interest in control methods for invasive wild pigs (Sus scrofa) has increased due to their range expansion, population growth, and an improved understanding of their destructive ecological and economic effects. Recent technological advances in traps for control of pig populations facilitate capture of entire social groups (sounders), but the efficacy of “whole-sounder” trapping strategies is heavily dependent on the degree of territoriality among sounders, a topic little research has explored. We assessed territoriality in wild pig sounders on the Savannah River Site, South Carolina, USA,...

Amid reports from western US wildland fire managers that, compared to when many started their careers, fires are burning longer throughout the day before reducing in intensity overnight, we examined decadal changes in nighttime vapor pressure deficits over the western United States with a focus on the summer fire season. We calculated changes using a recently updated observation-assimilating reanalysis (ERA5) available at hourly resolution over the 1980–2019 period. Analysis identifies the proximate cause (atmospheric temperature vs. moisture content) of the observed changes and the extent...

Downed woody material (DWM) is a unique part of the forest carbon cycle serving as a pool between living biomass and subsequent atmospheric emission or transference to other forest pools. Thus, DWM is an individually defined pool in national greenhouse gas inventories. The diversity of DWMcarbon drivers (e.g., decay, tree mortality, orwildfire) and associated high spatial variability make this a difficult-to-predict component of forest ecosystems. Using the now fully established nationwide inventory of DWM across the United States (US), we developed models, which substantially improved...

A demographic Allee effect refers to increasing per capita population growth with increasing abundance. It arises from component Allee effects, which exist when some component of individual fitness has a positive relationship with density. Newly arrived populations tend to be small, and their establishment success is influenced by various factors, including demographic Allee effects. Identifying mechanisms driving the Allee effect is of relevance for understanding establishment failure, developing strategies for improving biological control and conservation, and for managing biological...