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Background: Hillslopes provide critical watershed ecosystem services such as soil erosion control and storm flow regulation through collecting, storing, and releasing rain water. During intense rainstorms, rainfall intensity and infiltration capacity on the hillslope control Hortonian runoff while the topographic attributes of the hillslope (e.g., slope, aspect, curvature) and the channel network define the structural hydraulic connectivity that determines how rapidly excess water is transferred. This paper discusses literature on the link between topographic attributes and hydrologic...

Under the exacerbation of climate change, cli· mate extreme events. especially for drought, happened frequently and intensively across the globe with greater spatial differences. We used the Standardized Precipitation-Evapotranspiration Index computed from the routine meteorological observations at 269 sites in Southwest China (SWC) to study the drought characteristics (e.g., extent, duration and intensity) and their decadal variations during I 971 - 2012. It was revealed that the drought, in responses to the coupling between decadal precipitation and potential evapotranspiration (PET)...

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...

Soil erosion continuously redistributes soil and associated soil organic matter (SOM) on the Earth's surface, with important implications for biogeochemical cycling of essential elements and terrestrial carbon sequestration. Despite the importance of soil erosion, surprisingly few studies have evaluated the sources of eroded carbon (C). We used natural abundance levels of the stable and radioactive isotopes of C (13C and 14C) and stable isotope of nitrogen (15N) to elucidate the origins of SOMeroded fromlow-order catchments along the western slopes of the Sierra Nevada of California, USA....

The effect of fine-scale topographic variability on model estimates of ecohydrologic responses to climate variability in California’s Sierra Nevada watersheds has not been adequately quantified and may be important for supporting reliable climate-impact assessments. This study tested the effect of digital elevation model (DEM) resolution on model accuracy and estimates of the sensitivity of ecohydrologic responses to inter-annual climate variability. The Regional Hydro-Ecologic Simulation System (RHESSys) was applied to eight headwater, high-elevation watersheds located in the Kings River...

With humans altering climate processes, biogeochemical cycles, and ecosystem functions (1), governments and societies confront the challenge of shaping a sustainable future for people and nature. Policies and practices to address these challenges must draw on social sciences, along with natural sciences and engineering (2). Although various social science approaches can enable and assess progress toward sustainability, debate about such concrete engagement is outpacing actual use. To catalyze uptake, we identify seven key social concepts that are largely absent from many efforts to pursue...

An important goal of restoring fire to upland oak-dominated communities that have experienced fire exclusion is restoring groundcover plant species diversity and composition indicative of fire-maintained habitats. Several studies have shown that fire alone, however, may not be sufficient to accomplish this goal. Furthermore, treatment-driven declines in rare forest specialists could negate the benefits of ecological restoration in these ecosystems. I present the results of an experiment examining effects of tornado-generated canopy openings and biennial spring burning on groundcover...

Carya sinensis (Chinese Hickory, beaked walnut, or beaked hickory) is an endangered species that needs urgent conservation action. Here, we reported the complete chloroplast (cp) genome sequence and the genomic features of the C. sinensis cp, which is the first complete cp genome of any member of Carya. The C. sinensis cp genome was 160,195 bp, containing a large single copy region (LSC) of 89,541 bp and a small single copy region (SSC) of 18,538 bp separated by a pair of 26,058 bp inverted repeat regions (IRs). The genome contained 135 genes, including 87 protein-coding genes (79 species),...

The efficiency of national forest monitoring efforts can be increased by the judicious incorporation of ancillary data. For instance, a fixed number of ground plots might be used to inform a larger set of annual estimates by observing a smaller proportion of the plots each year while augmenting each annual estimate with ancillary data in order to reduce overall costs while maintaining a desired level of accuracy. Differencing successive geo-rectified remotely sensed images can conceivably provide forest change estimates at a scale and level of accuracy conducive to the improvement of...

Governmental and nongovernmental organizations charged with managing natural resources increasingly emphasize the need to work across jurisdictional boundaries. Their challenge is to manage shifting resources under rapidly changing climate and land-use scenarios. Scientists, resource managers, and conservation planners, and their organizations and agencies routinely collaborate on projects to solve specific problems. Cooperative frameworks to programmatically address complex social–environmental issues and develop shared research, planning, and implementation priorities are relatively new....