Riparian zone vegetation can influence terrestrial and aquatic food webs through variations in the amounts, timing, and nutritional content of leaf and other litter inputs. Differences in vegetation composition and density, as well as riparian topography, may modulate the strength and quality of these inputs. Changes in inputs to small order streams affect the processes and condition of adjacent and downstream reaches based on the amount of particulate organic matter that is intercepted, retained, or exported. The central Oregon Coast Range provides an ideal opportunity to study how deciduous dominated and coniferous dominated riparian forests influence small streams within a matrix of managed riparian forests. In coastal Oregon riparian forests, we investigated lateral and vertical litter inputs to sixteen streams throughout a year and assessed how these inputs were influenced by density of deciduous dominated (mainly red alder (Alnus rubra)) or coniferous dominated (mainly Douglas-fir (Pseudotsuga menziesii)) overstory, understory, and lateral slope. Deciduous site vertical litter inputs (504 g m-2 yr-1 (95% CI: 447-562)) were estimated to exceed those from coniferous sites (394 g m-2 yr-1 (336-452)) by 110 g m-2 (29-192) over the full year. Annual lateral inputs (per meter of stream bank on one side) at deciduous sites (109 g m-1 yr-1 (76-143)) were estimated to be 47 g m-1 (1-95) more than coniferous sites (63 g m-1 yr-1 (29-97)). Annual inputs at coniferous sites were dominated by deciduous leaves, coniferous needles, and twig litter types. Deciduous leaves, deciduous-other, and small unidentifiable litter types dominated the annual inputs at deciduous sites. When evaluated temporally, November was the most pivotal month differentiating coniferous and deciduous site litter inputs. At deciduous sites, lateral litter movement increased with slope, but we did not see the same relationship for coniferous sites except in spring/summer months. Lateral inputs were quantitatively greatest in autumn months for both overstories, but were proportionately greater in winter. Regardless of slope, there was no indication that understory plants were obstructing annual lateral litter inputs or that annual lateral litter inputs were moving more than 5 m down slope. The percent nitrogen of annual total vertical litter was estimated to be 1.9% N (1.5-2.4) at deciduous sites and 1.2% N (0.8-1.7) at coniferous sites. Average % nitrogen of individual litter types were either greater in deciduous sites or not different among overstories, indicating that one can generally expect coniferous sites to have lower % N litter inputs overall. The annual nitrogen flux entering each meter-length (from above and both sides) of standard 4 m-wide streams at a deciduous sites (42 g N m-1 of stream) was twice that of coniferous sites (21 g N m-1 of stream). Annual total litter carbon flux into each meter-length of 4 m-wide streams was estimated to be 1154 g C m-1 of stream at deciduous sites and 880 g C m-1 of stream at coniferous sites. On average, autumn months (October-December) accounted for 46-59% of annual vertical C flux and 56-70% of annual vertical N flux at coniferous and deciduous sites. Our results suggest that red alder dominated riparian zones of the central Oregon Coast Range have significantly different quantity, timing, and quality of leaf litter inputs to streams than conifer dominated forests. Varied topography adjacent to streams with red alder dominated overstory has greater impact on the quantity, quality, and timing of total inputs than at coniferous sites. The cumulative effects from many small red alder dominated streams exporting to downstream reaches include more pronounced seasonality of litter delivery, with greater carbon and nitrogen loading annually, than expected from conifer dominated streams. Differences in overstory and topography in Oregon Coast Range riparian forests directly impact the delivery of nutrients and can affect the structure and composition of food webs in these ecosystems.

The primary objective of this book is to provide students and laboratory instructors at universities and professional ecologists with a broad range of established methods to study plant litter decomposition. Detailed protocols for direct use in the field or laboratory are presented in an easy to follow step-by-step format. A short introduction to each protocol reviews the ecological significance and principles of the technique and points to key references.

Methods in Stream Ecology: Volume 2: Ecosystem Structure, Third Edition, provides a complete series of field and laboratory protocols in stream ecology that are ideal for teaching or conducting research. This new two-part edition is updated to reflect recent advances in the technology associated with ecological assessment of streams, including remote sensing. Volume two covers community interactions, ecosystem processes and ecosystem quality. With a student-friendly price, this new edition is key for all students and researchers in stream and freshwater ecology, freshwater biology, marine ecology and river ecology. This book is also supportive as a supplementary text for courses in watershed ecology/science, hydrology, fluvial geomorphology and landscape ecology. Methods in Stream Ecology, 3rd Edition, Volume 1: Ecosystem Structure, is also available now! - Provides a variety of exercises in each chapter - Includes detailed instructions, illustrations, formulae and data sheets for in-field research for students - Presents taxonomic keys to common stream invertebrates and algae - Includes website with tables and a links written by leading experts in stream ecology

I examined factors regulating decomposition rates of red alder (Alnus rubra)) and Douglas-fir (Pseudotsuga menziesii) leaf litter in Coast Range riparian areas in western Oregon. Overall, this study was designed to examine the influence that leaf litter quality characteristics and decomposition site treatment have on decomposition rates, to provide a better understanding of how vegetation management can impact nutritional subsidies and nutrient cycles within these riparian systems. I employed the litterbag method to compare decomposition rates of litter with different initial chemistry in sites of different N availability. Specifically, this study investigates the role of litter source, riparian decomposition site, and how differences in N (both endogenous and exogenous) may influence the decomposition dynamics of red alder and Douglas-fir leaf litter. I addressed the following research questions: 1) How do the decomposition rates of red alder and Douglas-fir differ? 2) Do differences in chemical measures of initial litter quality (eg. N, Ca, lignin, cellulose, C:N) correlate with different rates of decomposition in Douglas-fir (8 different sources of Douglas-fir litter)? 3) Does dominance of a site by either red alder or Douglas-fir overstory) influence decomposition rates? 4) Does N fertilization increase the rate of litter decomposition under Douglas-fir overstories? Results suggest that red alder litter decomposes more rapidly than Douglas-fir litter under either canopy, but the difference in decomposition rates is greater under a red alder overstory than under a Douglas-fir overstory. N mineralization began immediately following placement of the red alder litter bags and more N was mineralized in red alder litter decomposing under red alder overstories than under Douglas-fir overstories. Compared to red alder, Douglas-fir litter decomposition did not vary by overstory treatment. Generally, Douglas-fir litter went through an immobilization period, with only high N litter mineralizing N under unfertilized Douglas-fir overstories. Both low- and high-N Douglas-fir litter immobilized more N under red alder overstories, and under fertilized Douglas-fir conditions. In fertilized plots under Douglas-fir overstories, high-N litter was still immobilizing N after two years. In contrast, low-N Douglas-fir litter immobilized N throughout the 2 year period under all treatments. This study indicates strong species-specific effect of overstory composition on riparian ecosystem processes. These effects can influence energy and nutrient budgets of riparian food webs, and suggest a need for broader consideration of potential impacts resulting from conversion of red alder to Douglas-fir dominated riparian area. Surprisingly, rates of Douglas-fir litter decomposition were negatively related to initial litter nitrogen concentrations across the range 0.7 - 1.4% N, contrary to patterns observed across species in other ecosystems. N fertilization exerted a minor influence on decomposition rates of Douglas-fir, with decomposition rates slower in fertilized Douglas-fir plots. These results highlight the complicated relationship between decomposition of high lignin litter and N availability and suggest that under such conditions decomposition can be dramatically reduced.

The Clean Water Act (CWA) requires that wetlands be protected from degradation because of their important ecological functions including maintenance of high water quality and provision of fish and wildlife habitat. However, this protection generally does not encompass riparian areasâ€"the lands bordering rivers and lakesâ€"even though they often provide the same functions as wetlands. Growing recognition of the similarities in wetland and riparian area functioning and the differences in their legal protection led the NRC in 1999 to undertake a study of riparian areas, which has culminated in Riparian Areas: Functioning and Strategies for Management. The report is intended to heighten awareness of riparian areas commensurate with their ecological and societal values. The primary conclusion is that, because riparian areas perform a disproportionate number of biological and physical functions on a unit area basis, restoration of riparian functions along America's waterbodies should be a national goal.