Treesearch

Variable radius plot surveys can require updated estimates when the quality of previous estimates have declined over time. We developed a statistical estimator for this purpose that is the product of two estimators, one estimator is for the updated volume-to-basal-area ratio and the other estimator is for the updated basal area. Our estimator relies only on the surveyor identifying previously measured trees and does not require the identification of ingrowth, which simplifies its application. We also propose a variance estimator that relies on the bootstrap method. We investigate the point...

Alaska’s boreal forests are experiencing rapid changes in climate that may favor deciduous-dominated systems, with important implications for global biogeochemical and energy cycles. However, aspen (Populus tremuloides Michx.) has experienced substantial defoliation from the aspen leaf miner (Phyllocnistis populiella Cham., hereafter ALM) in Alaska, resulting in significant growth reductions. We conducted a tree-ring and Δ13C study to test the hypothesis that moisture limitation may have predisposed aspen to leaf miner damage. Contrary to our hypothesis, differences in climate-growth...

Niche construction by biota has been frequently reported for animals and plants, but fungi have received less attention. For mycorrhizal fungi, mutualistic niche construction has been proposed where partners construct niches for each other. However, few eco-evolutionary mechanisms leading to mutualistic symbiotic feedback have been described. Here we report niche construction by two ectomycorrhiza-forming species of truffles, Tuber aestivum and T. melanosporum. The soils of 263 spots of these Tuber, which create bare patches (brûlés), have been monitored (9–10 years) in natural forests to...

Monitoring provides the foundation for evaluating recovery of endangered species, yet many species lack monitoring programs designed to integrate a species’ unique attributes, specific monitoring objectives, and principles of statistical sampling theory. We developed a framework for monitoring and assessment of endangered light-footed Ridgway’s rails (Rallus obsoletus levipes) across their U.S. range, relative to multi-scale recovery goals. We created spatially explicit sample units and a sampling frame covering all potential habitat to facilitate range-wide probability sampling, and also...

Headwater streams are reliant on riparian tree leaf litterfall to fuel brown food webs. Terrestrial agents like herbivores and contaminants can alter plant growth, litter production, litter quality, and the timing of litterfall into streams, influencing aspects of the brown food web. At Mount St. Helens (USA), early successional streams are developing willow (Salix sitchensis) riparian zones. The willows are attacked by stem-boring herbivores, altering litter quality and the timing of litterfall. Within a established experimental plots, willows (male and female plants) were protected from...

Amphibians face many challenges in their conservation, including threats from emerging infectious pathogens/parasites and habitat degradation. In diverse amphibian communities, where multiple emerging pathogens tend to co-occur, we know little about how the structural partitioning of host specificity impacts population maintenance despite disease. Here, we used field data from amphibian communities in north Florida to investigate host-specific traits influencing the prevalence, intensity, and transmission of three emerging pathogens of amphibians: Batrachochytrium dendrobatidis (Bd),...

Camera traps deployed with olfactory attractants are used to survey rare and elusive carnivores. Study areas with deep snowpack and rugged terrain present challenges and risks to field personnel, who traditionally must revisit camera stations regularly to refresh attractants. In such locations, alternative overwinter survey protocols that include a persistent attractant would improve both the safety and efficiency of camera-trap surveys. We present a protocol for installing camera traps and automated scent dispensers on trees at above-average maximum snow depth to eliminate the need for...

Introduction: Habitat loss and degradation pose significant threats to global fish and wildlife populations, prompting substantial investments in habitat creation and restoration efforts. Not all habitats provide equal benefits, leading to challenges in prioritizing restoration actions. For example, juvenile anadromous salmonids require high quality rearing aquatic habitats to achieve the physiological requirements needed to successfully migrate to the ocean. However, there are profound disagreements among anadromous salmon restoration managers whether it is best to focus efforts on...

Managers invest substantial resources to promote recovery of declining anadromous fish stocks. Recovery strategies are manifold and often include management actions intended to stimulate somatic growth, increase in-river survival, and motivate juvenile outmigration during favorable environmental conditions. Evaluating the efficacy of these management actions is difficult, however, because monitoring data that explicitly track individuals from egg deposition to juvenile outmigration are typically lacking. We developed an integrated population model that links two different and often...

Wildfire activity throughout western North America is increasing which can have important consequences for species persistence. Native species have evolved disturbance-adapted traits that confer resilience to natural disturbance provided disturbances operate within their historical range of variability. This resilience can erode as disturbance regimes change and begin operating outside this range. We assessed wildfire impacts during 1987–2018 on the northern spotted owl, an imperiled species with complex relationships with late and early seral forest in the Pacific Northwest, USA. We...