Treesearch

Cross-validation using randomized subsets of data—known as k-fold cross-validation— is a powerful means of testing the success rate of models used for classification. However, few if any studies have explored how values of k (number of subsets) affect validation results in models tested with data of known statistical properties. Here, we explore conditions of sample size, model structure, and variable dependence affecting validation outcomes in discrete Bayesian networks (BNs). We created 6 variants of a BN model with known properties of variance and collinearity, along with data sets of n...

The Fisher (Pekania pennanti) is a mesocarnivore of conservation concern in the Pacific coastal region of North America with a diverse but poorly understood diet. From 1995 to 2001, we collected 297 scats from 11 radio-collared females and 83 scats from 8 radio-collared males, and used frequency of occurrence (percentage of scats containing a particular food item) to investigate their diets. Mammals were the most frequently occurring food item in the diets of both female and male Fishers (84.8 and 77.1 % of scats, respectively); however, the prevalence of small (≤166 g) mammalian prey was...

This research expands the applicability of the Feasible Goals (FGoal) Pareto frontier multiple criteria method to display the Edgeworth–Pareto hull using interactive decision maps (IDMs). Emphasis is placed upon the development of a communication architecture to display the Pareto frontiers, which includes a client device, a web server, and a dedicated computation server implemented with sockets. A standalone application on the latter processes client-server requests and responses to display updated information on the client. Specifically, the dedicated computation server is responsible...

Multiple restoration actions have been implemented in response to declining salmon populations. Among these is the addition of salmon carcasses or artificial nutrients to mimic marine-derived nutrients historically provided by large spawning runs of salmon. A key assumption in this approach is that increased nutrients will catalyze salmon population growth. Although effects on aquatic ecosystems have been observed during treatments, it is unclear whether permanent population increases for salmon will occur. To test this assumption and address associated uncertainties, we linked a food web...

Communities and protected areas worldwide have initiated programs to protect and promote dark night skies. Yet, limited research has explored how and why night skies become of interest or meaningful to people. Because night skies are literally beyond human reach, we focus on how visitors to a U.S. national park imagine night skies and invoke imaginaries that make night skies meaningful. Drawing from interviews, we examine how visitors use symbolic language, narrative, and other discursive practices to develop the social, cultural, and spatial contexts of their night sky experiences....

Exposure to wildfire smoke causes adverse health outcomes, suggesting the importance of accurately estimating smoke concentrations. Geostatistical methods can combine observed, modeled, and satellite-derived concentrations to produce accurate estimates. Here, we estimate daily average ground-level PM2.5 concentrations at a 1 km resolution during the October 2017 California wildfires, using the Constant Air Quality Model Performance (CAMP) and Bayesian Maximum Entropy (BME) methods to bias-correct and fuse three concentration datasets: permanent and temporary monitoring stations, a chemical...

Mentoring has had a recent resurgence as the key to achieving both individual and organizational goals, especially as workforce diversification efforts have led to the hiring of new talent. Few studies have evaluated mentoring within an organization or examined changes in mentoring practices over time. We describe the role and status of mentoring for current fish biologists in the USDA Forest Service, including correlations between participation in mentoring and gender, race/ethnicity, career level, time in career, and job satisfaction based on a survey of agency employees (n = 136)....

Ecological resources for fishes in stream food webs shift over space and time, providing a complex template of available resources that can be used for growth. We tracked water temperature in conjunction with young-of-year Coho Salmon size, growth, and diet in 2 streams with contrasting thermal regimes: a groundwater stream with colder temperatures and lower thermal variability all year and a surface-water stream with greater thermal variability and warmer summer temperatures more conducive to young-of-year salmon growth. We hypothesized that fry emergence would occur when rearing condition...

Background: In forest trees, genetic markers have been used to understand the genetic architecture of natural populations, identify quantitative trait loci, infer gene function, and enhance tree breeding. Recently, new, efficient technologies for genotyping thousands to millions of single nucleotide polymorphisms (SNPs) have finally made large-scale use of genetic markers widely available. These methods will be exceedingly valuable for improving tree breeding and understanding the ecological genetics of Douglas-fir, one of the most economically and ecologically important trees in the...

Glaciers have shaped past and present habitats for Pacific salmon (Oncorhynchus spp.) in North America. During the last glacial maximum, approximately 45% of the current North American range of Pacific salmon was covered in ice. Currently, most salmon habitat occurs in watersheds in which glacier ice is present and retreating. This synthesis examines the multiple ways that glacier retreat can influence aquatic ecosystems through the lens of Pacific salmon life cycles. We predict that the coming decades will result in areas in which salmon populations will be challenged by diminished water...