A METHOD OF MODELING SOURCE AREA RESPONSE TO CLIMATE VARIABILITY

ABSTRACT: A modeling framework for understanding spatially-explicit relationships between soil moisture dynamics and streamflow generation in upland humid forested watersheds is described. The framework consists of a dynamic canopy interception module and a 2D finite element hillslope hydrology model (IHDM4) having hillslope planes objectively delineated using contour-based terrain analysis (TAPES-C). This approach is fine-scaled both in space and time allowing for the inclusion of topographic and soil heterogeneities necessary for mapping oscillations in the variable source areas of streamflow generation. The modeling framework is implemented for a small control watershed (WS2) at the Coweeta Hydrologic Laboratory. Simulation results to be presented at the conference include the climate-scale response of variable source areas for hillslope cross-sections to hourly climate data spanning years in which total precipitation was: (a) >20% above average, (b) near average, (c) >20% below average

Matrix and Tensor Factorization Methods for Toxicogenomic Modeling and Prediction

Peer reviewe

Negative Regulation of Active Zone Assembly by a Newly Identified SR Protein Kinase

A neuronal serine-arginine protein kinase that localizes to the presynaptic active zone is required for kinase-dependent repression of active zone assembly

Genome-Wide Analysis of Histone H3 Lysine9 Modifications in Human Mesenchymal Stem Cell Osteogenic Differentiation

Mesenchymal stem cells (MSCs) possess self-renewal and multi-lineage differentiation potentials. It has been established that epigenetic mechanisms such as histone modifications could be critical for determining the fate of stem cells. In this study, full human genome promoter microarrays and expression microarrays were used to explore the roles of histone modifications (H3K9Ac and H3K9Me2) upon the induction of MSC osteogenic differentiation. Our results revealed that the enrichment of H3K9Ac was decreased globally at the gene promoters, whereas the number of promoters enriched with H3K9Me2 was increased evidently upon osteogenic induction. By a combined analysis of data from both ChIP-on-chip and expression microarrays, a number of differentially expressed genes regulated by H3K9Ac and/or H3K9Me2 were identified, implicating their roles in several biological events, such as cell cycle withdraw and cytoskeleton reconstruction that were essential to differentiation process. In addition, our results showed that the vitamin D receptor played a trans-repression role via alternations of H3K9Ac and H3K9Me2 upon MSC osteogenic differentiation. Data from this study suggested that gene activation and silencing controlled by changes of H3K9Ac and H3K9Me2, respectively, were crucial to MSC osteogenic differentiation

Changes in Riparian Vegetation Buffers in Response to Development in Three Oregon Cities

Riparian vegetation buffer loss was investigated for three cities with contrasting local regulatory controls in urbanizing northwest Oregon. The cities examined were Hillsboro, Oregon City and Portland, all having experienced high rates of population increase in the 1990s. All cities are covered under Oregon’s land use law that provides goals for the protection of open space and natural resources. On the municipality level, regulatory controls in Portland included a system of environmental zoning for riparian area protection, while regulatory controls on development in riparian areas in Hillsboro and Oregon City were less stringent. Digital aerial photographs covering buffer areas within 200 m of all permanent streams for these cities were digitized for the years 1990 and 1997 using criteria including minimum inter-patch distance of 5 m for adjacent classes and minimum patch area of 20 m2. Cover classes were divided into vegetation areas adjacent to stream and total, as well as woody and unmanaged vegetation areas. Banding analysis was performed for these vegetation coverages for several buffer widths out to 100 m from streams. Results for the 1990 to 1997 period showed larger losses for unmanaged adjacent vegetation 100 m from stream for Hillsboro and Oregon City (≥1.5 percent/year) than for Portland (/year). For adjacent tree vegetation within a 100 m buffer width, again Hillsboro and Oregon City had higher rates of loss (\u3e1 percent/year), while Portland lost trees in the 100 m buffer at a lower rate (/ year). Factors explaining these lower rates of riparian buffer loss for Portland may include both a higher amount of riparian area in public ownership and more stringent local regulatory controls on development in riparian buffers. These results also demonstrate that vegetated riparian buffers continue to be lost due to development in growing Oregon municipalities regardless of the level of regulatory protection

Riparian Wetland Plant Response to Livestock Exclusion in the Lower Columbia River Basin

The purpose of this study was to examine the characteristics of riparian plant communities along a gradient of livestock exclusion in the Lower Columbia River Basin (LCRB) located in the Pacific Northwest region of the United States. Livestock exclusion from riparian wetlands is a common passive restoration technique. Few studies, however, have focused on the effects of livestock grazing or the exclusion of livestock grazing on these ecosystems. Vegetation community composition was examined in two passive restoration sites, three and 13 years since livestock exclusion, and in a reference site with continued livestock grazing. We hypothesized native plant species richness would be lower in the excluded wetlands than in the grazed wetland due to the competitive exclusion from an increase in non-native plant dominance in the absence of grazing. The grazed wetland had significantly (P \u3c 0.02) greater mean total species richness (23.3 ± 1.6; mean ± 1 standard error), native (10.2 ± 0.5), and non-native (12 ± 1.5) species richness than both the excluded wetlands. Mean total species richness did not differ significantly (P = 0.088) between the three-year (12 ± 1.4) and 13-year (5.5 ± 2.3) excluded wetlands. Mean native and non-native species richness also did not differ significantly (native P = 0.088. non-native P = 0.064) between the three-year (native 6.3 ± 0.6, non-native 5 ± 2.3) and 13-year (native 2.8 ± 1.3, non-native 2.7 ± 1.1) excluded wetlands. However, native species abundance as indicated by percent cover was significantly (P \u3c 0.02) lower in the 13-year excluded wetland (4.2 ± 2.0%) than both the three-year excluded (51.5 ± 3.9%) and grazed (23.2 ± 3.3%) wetlands. The invasive grass, Phalaris arundinacea (reed canarygrass), was found to be the dominant vegetation cover in all three wetlands, with average relative cover ranging from 95.2 ± 2.0% at the 13-year exclusion site to 52.8 ± 4.1% at the grazing site, and 43.0 ± 4.0% cover at the three-year exclusion site. These observations suggest that livestock exclusion alone may be an ineffective strategy for restoring riparian plant communities in regions such as LCRB where invasive species like reed canarygrass are abundant. More effective management alternatives might include short-term livestock exclusion and reintroduced targeted grazing to both reduce livestock impacts and control reed canarygrass dominance

Integrating multiple aquatic values: Perspectives and a collaborative future for river science

The study and management of rivers have undergone a metamorphosis over the last four decades, transitioning from individual sub-disciplines towards interdisciplinary approaches and an increased focus on viewing riverine landscapes as social-ecological systems. Within this context, there is a growing emphasis on the need to take resilience-based approaches to living with rivers in a sustainable way that maximises public security, infrastructure protection, and economic, ecological, and cultural benefits and values. The concept of viewing rivers as social-ecological systems is gaining traction in science and management discourse; however, the idea is not new, and indigenous knowledge systems consistently place humans within the natural world. Integrating environmental knowledge, in its various forms, plays a key role in understanding issues and developing solutions for freshwater managers, especially in the context of rivers as social-ecological systems. The 5th Biennial Symposium of the International Society for River Science conference, themed "Integrating Multiple Aquatic Values," provided a forum for sharing environmental knowledge underpinning freshwater management critical for achieving multiple goals. The papers in this special issue highlight the fundamental properties of rivers as social-ecological systems and the attempts to integrate multiple values concerned with rivers and their landscapes. From a series of case studies, a set of challenges and opportunities emerge that have the potential to further the management and research of rivers as social-ecological systems and integrate multiple aquatic values. Key to this is acknowledging and respecting the value that indigenous worldviews and knowledge bring. We also echo the call of other authors that if the overall goals are that rivers, societies, and their interactions are to result in positive social and ecological outcomes for people and rivers, then integrating and respecting multiple values and knowledge systems will be required