Treesearch

Effects of hydraulic redistribution (HR) on hydrological, biogeochemical, and ecological processes have been demonstrated in the field, but the current generation of standard earth system models does not include a representation of HR. Though recent studies have examined the effect of incorporating HR into land surface models, few (if any) have done cross-site comparisons for contrasting climate regimes and multiple vegetation types via the integration of measurement and modeling. Here, we incorporated the HR scheme of Ryel et al. (2002) into the NCAR Community Land Model Version 4.5...

Environmental change and long-term fire management in the western United States have created conditions that facilitate high-intensity burn areas in forested systems. Such burns may have dramatic effects on the soil microbial communities. In this study, we utilized experimental infrastructure in the Pringle Falls Experimental Forest in Oregon, where ten pairs of sites were assigned to either high burn (HB) or low burn (LB) intensity treatments to examine fungal community responses. In these treatments, understory shrubs and logging debris were masticated and broadcast burned (LB) or piled...

Mountain environments are currently among the ecosystems least invaded by non-native species; however, mountains are increasingly under threat of non-native plant invasion. The slow pace of exotic plant invasions in mountain ecosystems is likely due to a combination of low anthropogenic disturbances, low propagule supply, and extreme/steep environmental gradients. The importance of any one of these factors is debated and likely ecosystem dependent.We evaluated the importance of various correlates of plant invasions in the Wallowa Mountain Range of northeastern Oregon and explored whether...

1. The Strategic Plan for Biodiversity (2011–2020), adopted at the 10th meeting of the Conference of the Parties to the Convention on Biological Diversity, sets 20 Aichi Biodiversity Targets to be met by 2020 to address biodiversity loss and ensure its sustainable and equitable use. Aichi Biodiversity Target 11 describes what an improved conservation network would look like for marine, terrestrial and inland water areas, including freshwater ecosystems.2. To date, there is no comprehensive assessment of what needs to be achieved to meet Target 11 for freshwater biodiversity. Reports on...

Background: Vegetation change in high latitude tundra ecosystems is expected to accelerate due to increased wildfire activity. High-severity fires increase the availability of mineral soil seedbeds, which facilitates recruitment, yet fire also alters soil microbial composition, which could significantly impact seedling establishment. Results: We investigated the effects of fire severity on soil biota and associated effects on plant performance for two plant species predicted to expand into Arctic tundra. We inoculated seedlings in a growth chamber experiment with soils collected from the...

Context Forecasting the expansion of forest into Alaska tundra is critical to predicting regional ecosystem services, including climate feedbacks such as carbon storage. Controls over seedling establishment govern forest development and migration potential. Ectomycorrhizal fungi (EMF), obligate symbionts of all Alaskan tree species, are particularly important to seedling establishment, yet their significance to landscape vegetation change is largely unknown. Objective We used ALFRESCO, a landscape model of wildfire and vegetation dynamics, to explore whether EMF inoculum potential influence...

1. Protection of places important for aesthetic, ecological, and cultural values has been a goal of conservationists for over 150 years. Cornerstones of place-based conservation include legal designations, international agreements, and purchase by public or non-profit organizations.2. In the Salmon River catchment, Oregon, protections were initially developed in the 1930s for the freshwater riparian corridor and forestry research in the uplands. Over time, additional protections in the estuary and nearshore marine environments were added, motivated by local desire to protect and restore...

Forested riparian buffer zones are used in conjunction with upland forest management, in part, to provide for the recruitment for large wood to streams. Small headwater streams account for the majority of stream networks in many forested regions. Yet, our understanding of how riparian buffer width influences wood dynamics in headwater streams is relatively less developed compared to larger fish-bearing streams. The effects of riparian buffer width on instream wood loading after thinning can be difficult to discern due to the influence of basin characteristics and reach-scale geomorphology...

Although biogeographic patterns are the product of complex ecological processes, the increasing com-plexity of correlative species distribution models (SDMs) is not always motivated by ecological theory,but by model fit. The validity of model projections, such as shifts in a species’ climatic niche, becomesquestionable particularly during extrapolations, such as for future no-analog climate conditions. To exam-ine the effects of model complexity on SDM predictive performance, we fit statistical models of varyingcomplexity to simulated species occurrence data arising from data-generating...

The brine shrimp (Artemia salina) bioassay was used to screen 211 methanol extracts from 128 species of Pacific Northwest plants in search of general cytotoxic activity. Strong toxicity (LC50 < 100 μg/ml) was found for 17 extracts from 13 species, with highest activity observed for Angelica arguta roots at <10 μg/ml. Notably, four species of cedar trees and one of juniper in the family Cupressaceae dominated this group with LC50 for heartwood extracts ranging from 15 to 89 μg/ml. Moderate toxicity (LC50 100–500 μg/ml) was found in 38 extracts from 27 species, while weak toxicity (LC50...