Treesearch

Food web ecology has revolutionized our understanding of ecological processes, but the drivers of food web properties like trophic position (TP) and food chain length are notoriously enigmatic. In terrestrial ecosystems, above-and belowground systems were historically compartmentalized into “green” and “brown” food webs, but the coupling of these systems by animal consumers is increasingly recognized, with potential consequences for trophic structure. We used stable isotope analysis (δ13C, δ15N) of individual amino acids to trace the flow of essential biomolecules and jointly measure...

There are increasing concerns about the declining population trends of small mammalian carnivores around the world. Their conservation and management are often challenging due to limited knowledge about their ecology and natural history. To address one of these deficiencies for western spotted skunks (Spilogale gracilis), we investigated their diet in the Oregon Cascades of the Pacific Northwest during 2017–2019. We collected 130 spotted skunk scats opportunistically and with detection dog teams and identified prey items using DNA metabarcoding and mechanical sorting. Western spotted skunk...

Detecting spatiotemporal changes in the abundances of organisms is key to effectively conserving species. While indices of abundance have long been used, there has been a shift toward model-based estimators that account for the detection process. Popular approaches including traditional occupancy models and N-mixture models entail tradeoffs. The traditional occupancy approach requires the researcher coarsen the characterization of abundance to the probability that a site is occupied or unoccupied. Conversely, N-mixture models make use of variation in counts, but perform poorly when...

We assessed attraction of pine engraver, Ips pini(Say) (Coleoptera: Curculionidae; Scolytinae), to pheromone-baited funnel traps treated with repellent semiochemicals in ponderosa pine, Pinus ponderosa var. scopulorumEngelm., forests in northern Arizona. Treatments included: 1) baited control (B, ipsdienol + lanierone), 2) 70 g of SPLAT Verb (a flowable, biodegradable formulation containing 10% verbenone, ISCA Technologies Inc., Riverside, CA, USA) + B, 3) 70 g of SPLAT Verb + (E)-2-hexen-1-ol+(Z)-2-hexen-1-ol + acetophenone + B, 4) 7.84-g verbenone pouch (Product #3413, Synergy Semiochemic...

Most recent implementations of low-cost electrical conductivity (EC) sensors intended for water quality measurements are based on simple two-pole designs. However, in marine settings, EC often exceeds the range where two-pole sensors provide reliable results. We have developed a simple four-pole EC sensor that relies exclusively on analog-to-digital measurements made using readily available circuit boards (pyboard v.1.1 or Raspberry Pi Pico 2040) programmed using MicroPython. Other than resistors and graphite or wire electrodes, no other electronic components are required for the EC...

Models that assess the vulnerability of freshwater species to shifting environmental conditions do not always account for short-duration extremes, which are increasingly common. Life cycle models for Pacific salmon (Oncorhynchus spp.) generally focus on average conditions that fish experience during each life stage, yet many floods, low flows, and elevated water temperatures only last days to weeks. We developed a process-based life cycle model that links coho salmon (Oncorhynchus kisutch) abundance to daily streamflow and thermal regimes to assess: (1) “How does salmon abundance respond...

Meltwater contributions to watersheds are shrinking as glaciers disappear, altering the flow, temperature, and biogeochemistry of freshwaters. A potential consequence of this landscape change is that streamflow patterns within glacierized watersheds will become more homogenous, potentially altering the capacity of watersheds to support Pacific salmon. To assess heterogeneity in stream habitat quality for juvenile salmon in a watershed in the Alaska Coast Mountains, we collected organic matter and invertebrate drift and measured streamwater physical and biogeochemical properties over the...

California contains a diverse flora, and knowledge of the pathogens that threaten those plants is essential to managing their long-term health. To better understand threats to California plant health, a meta-analysis of Phytophthoradetections within the state was conducted using publicly available sequences as a primary source of data rather than published records. Accessions of internal transcribed spacer (ITS) ribosomal DNA were cataloged from 800 Californian Phytophthoraisolates, analyzed, and determined to correspond to 80 taxa, including several phylogenetically distinct provisional...

Mechanical forest thinning treatments are implemented across the western United States (US) to improve forest health and reduce hazardous fuels. However, the main challenge in thinning operations is low financial feasibility. This study synthesized the stump-to-truck cost of forest thinning operations in the western US based on operations research articles published over the last 40 years (1980-2020). We systematically selected and reviewed 20 thinning studies to analyze key variables affecting machine productivity and harvesting costs. The average cost of forest thinning was lowest for a...

Based on current trends and policies aimed at decarbonizing energy systems, the conversion of biomass to bioenergy has the potential to grow rapidly, but such growth depends on the development of efficient, sustainable, and competitive biomass supply chains. As a result, the biomass supply chain has stimulated the interest of a diverse group of researchers across academia, government, and industry, and there is a need to synthesize and categorize the rapidly expanding literature in this field. We conducted a literature review using advanced bibliometric analysis and visualization of 1711...