Treesearch

Ecological disturbance is a key agent shaping the spatial and temporal landscape of food availability. In forests of western North America, disturbance from fire can lead to resource pulses of deadwood-associated arthropods that provide important prey for woodpeckers. Although the foraging strategies among woodpecker species often demonstrate pronounced differences, little is known about the ways in which woodpeckers exploit and partition prey in disturbed areas. In this study, we employed DNA metabarcoding to characterize and compare the arthropod diets of 4 woodpecker species in Washingto...

Streams and rivers are a rich repository of minute traces of genetic material from all organisms that live in or near the water, from the tiniest microbes to fish, mammals, and trees. This environmental DNA (eDNA) can tell a detailed story about the life within and around the waterbody.Brooke Penaluna and Richard Cronn, scientists with USDA Forest Service Pacific Northwest Research Station, have spent the past several years studying the potential uses of eDNA as a tool for understanding what’s living in Pacific Northwest streams. Through eDNA analysis, they have identified more than 900...

Migratory bird populations rely on a continuum of habitat along their migratory path. Along the Pacific Flyway in the United States, this habitat consists of land under a mix of different management entities and landownerships including federal, state, and local land management agencies, Tribes, and private landowners. Effective management of migratory bird habitat relies on coordination among these different entities to ensure both sustained flyway continuity and habitat quality sufficient to maintain healthy migratory bird populations. We consider the challenges involved in the conservati...

In the Pacific Northwestern USA, concerns regarding impacts of forest harvesting on visual quality, wildlife habitat, and carbon management have prompted evaluations of alternative silvicultural regimes for coast Douglas-fir (Pseudotsuga menziesii var. menziesii). Research was initiated in 1998 near Olympia WA USA to conduct long-term comparisons among six silvicultural regimes: clearcut (harvest all trees), two age (harvest all except 38 mature trees ha−1), patches (harvest 20% of the area in 0.6–2.0 ha tracts), groups (harvest 20% of the area in 0.1–0.5 ha tracts), thinning (reduce stand...

Watershed classification has long been a key tool in the hydrological sciences, but few studies have been extended to biogeochemistry. We developed a combined hydro-biogeochemical classification for watersheds draining to the coastal margin of the Northeast Pacific coastal temperate rainforest (1,443,062 km2), including 2,695 small coastal rivers (SCR) and 10 large continental watersheds. We used cluster analysis to group SCR watersheds into 12 types, based on watershed properties. The most important variables for distinguishing SCR watershed types were evapotranspiration, slope, snowfall,...

Pathogens can alter species composition and ecosystem function by causing direct and indirect effects on communities. Zoospores of the chytrid fungus Batrachochytrium dendrobatidis (hereafter, Bd), a pathogen implicated in worldwide amphibian declines, can be consumed by filter-feeding zooplankton and can damage mouthparts of infected amphibian larvae. Consequently, we hypothesized that this pathogen would affect the abundance of zooplankton and survival and feeding abilities of larval amphibian hosts. In turn, this could affect the algal food resources of zooplankton and tadpoles, which...

Increasing threats to amphibian and reptile species raise the urgency of their conservation. However, relative to other vertebrate groups at risk, amphibians and reptiles have low and more variable social capital; they are not generally high-priority natural goods and services valued by people. Consequently, relative to other groups such as birds, mammals, and economically important fish, they garner fewer conservation resources. With increasing risks, their situation degrades. We examine five societal sectors with herpetofaunal conservation interests in the United States (local communities...

Alaska has diverse boreal ecosystems across heterogeneous landscapes driven by a wide range of biological and geomorphic processes associated with disturbance and successional patterns under a changing climate. To assess historical patterns and rates of change, we quantified the areal extent of ecotypes and the biophysical factors driving change through photo-interpretation of 2200 points on a time-series (∼1949, ∼1978, ∼2007, ∼2017) of geo-rectified imagery for 22 grids across central Alaska. Overall, 68.6% of the area had changes in ecotypes over ∼68 years. Most of the change resulted...

Analysis of a 10 year reciprocal transplant study was performed to determine the influence of seed-source and local planting site climates on the bole taper of 8995 Douglas-fir (Pseudotsuga menziesii var. menziesii) trees. Trees were planted at 9 sites across Oregon and Washington, with 120 known families taken from 12 seed-source regions across California, Oregon, and Washington. Diameter at breast height (DBH) ranged from 0.1 to 22.9 cm, with tree ages ranging from 2 year-old seedlings to 12 year-old trees. Changes in Gini coefficients (ΔG) of diameters along tree boles, as a surrogate...

Every summer, wildfires burn thousands of acres of forests in the American West. After the fire, forest managers must decide what to do next: Leave the postfire landscape to recover naturally? Harvest some of the burned trees for timber? What combination of management actions is most likely to reduce the severity of a repeat wildfire and to make the forests more resilient?Morris Johnson, a research fire ecologist with the USDA Forest Service Pacific Northwest Research Station, is working with federal and tribal forest managers to answer these questions. He is conducting long-term, replicate...