Treesearch

Black ash (Fraxinus nigra) forests, which cover over 1.2 million hectares in the Great Lakes Region, are threatened by emerald ash borer (EAB; Agrilus planipennis), which is eliminating native populations of ash throughout the region. Understanding the contribution of black ash wetlands to local and regional species richness is critical in forming effective conservation policies and informing management plans for these imperiled habitats. We measured breeding bird and anuran communities in black ash wetlands and compared them to nearby non-black ash habitats for each taxa: aspen-dominated...

Understanding the effects of landscape management on northern bobwhite (Colinus virginianus; hereafter, bobwhite) population growth requires information about seasonal- and stage-specific demographic parameters linked across the annual cycle. We review results to date from 3 years (2016–2018) of an intensive field study evaluating drivers of bobwhite population dynamics and resource selection during the breeding and non-breeding season in southwest Missouri, USA using data from adult and juvenile bobwhite fitted with radio-transmitters. Land cover of our study sites ranged from large...

The hemlock woolly adelgid (Adelges tsugae (Annand)) is a serious invasive pest of hemlock trees in eastern North America. Multiple biological control agents have been the focus of research aimed at pest management and conserving hemlock communities. Three promising A. tsugae specialist predators are the beetle Laricobius nigrinus (Fender) (Coleoptera: Derodontidae) and flies in the genus Leucotaraxis (Diptera: Chamaemyiidae), Leucotaraxis argenticollis (Zetterstedt), and Leucotaraxis piniperda (Malloch). However, these flies are vulnerable to parasitism by wasps in the genera Pachyneuron...

Tradeoffs occur when deciding between improving forest inventory precision by increasing sample size or by augmenting cluster plot design factors like size or subplot separation distance. The nature of these tradeoffs changes with variation in type and scale of the spatial pattern of the attribute of interest. To understand the impacts of relationships between type and scale of spatial heterogeneity and cluster plot design efficiency, we constructed a factorial simulation experiment and analysed relationships among forest inventory cost, cluster plot design factors, and different spatial...

Humans promote and inhibit other species on the urban landscape, shaping biodiversity patterns. Institutional racismmay underlie the distribution of urban species by creating disproportionate resources in space and time. Here, we examine whether present-day street tree occupancy, diversity, and composition in Baltimore, MD, USA, neighborhoods reflect their 1937 classification into grades of loan risk—from most desirable (A = green) to least desirable (D = "redlined")— using racially discriminatory criteria. We find that neighborhoods that were redlined have consistently lower street tree...

Changes in sulfate (SO42−) deposition have been linked to changes in mercury (Hg) methylation in peatlands and water quality in freshwater catchments. There is little empirical evidence, however, of how quickly methyl-Hg (MeHg, a bioaccumulative neurotoxin) export from catchments might change with declining SO42− deposition. Here, we present responses in total Hg (THg), MeHg, total organic carbon, pH, and SO42− export from a peatland-dominated catchment as a function of changing SO42− deposition in a long-term (1998− 2011), whole-ecosystem, control-impact experiment. Annual SO42− deposition...

Women and Black, Indigenous, and People of Color (BIPOC) employees are underrepresented in science and natural resource management institutions. Student and recent graduate trainee and internship programs have been used to try to address this in United States federal agencies over the last few decades. Our study evaluates how effective such programs are at improving U.S. federal workforce diversity. We used a comprehensive employee dataset from the United States Department of Agriculture (USDA) Forest Service– which has the largest natural resource management workforce in the country–to...

Globalization and economic growth are recognized as key drivers of biological invasions. Alien species have become a feature of almost every biological community worldwide, and rates of new introductions continue to rise as the movement of people and goods accelerates. Insects are among the most numerous and problematic alien organisms, and are mainly introduced unintentionally with imported cargo or arriving passengers. However, the processes occurring prior to insect introductions remain poorly understood. We used a unique dataset of 1,902,392 border interception records from inspections...

Understanding flame spread and combustion dynamics in surface fuels is important for both planning and evaluating the impact of prescribed fires. However, prescribed fires tend to be conducted under light and unsteady wind conditions as compared with those which have been well studied for wildfire scenarios. To improve this understanding and provide data for next-generation fire models, it is necessary to collect detailed time-resolved observations of these processes. To accomplish this, a series of small-scale field experiments was conducted in pine needle litter. 10 m x 10 m plots were...

The increasing importance of prescribed fire use has led to an increased focus on the development of modelling tools suited to conditions typical of prescribed fire scenarios. An improved understanding of flame spread through porous surface fuels represents an important part of these efforts. In the lower wind speed conditions typical of many prescribed burns, the role of fuel structure may be of greater importance than in highly wind-aided flame spread scenarios. The porous nature of wildland fuel beds complicates efforts to apply existing, solid surface theories for flame spread in low...