Nitrogen deposition and cycling across an elevation and vegetation gradient in southern Appalachian forests
نویسندگان
چکیده
We studied nitrogen (N) cycling pools and processes across vegetation and elevation gradients in. the southern Appalachian Mountains in SE USA. Measurements included bulk deposition input, watershed export, throughfall fluxes, litterfall, soil N pools and processes, and soil solution N. N deposition increased with elevation and ranged from 9.5 to 12.4 kg ha-' yr-'. In all sites canopies retained inorganic N and lost organic N; net canopy retention varied among vegetation types. The high elevation site had the greatest litterfall N, soil N transformations, soil solution N, and greater stream N exports (0.60 kg ha-' p-'). Low elevation sites had lower litterfall N, soil N transformations, and soil solution N. Low stream N exports (0.14 kg ha-' p-') suggested N limitation. Multivariate analyses showed that abiotic variables account for up to 63% of the variation in biotic site characteristics.
منابع مشابه
Invariant community structure of soil bacteria in subtropical coniferous and broadleaved forests.
Soil bacteria may be influenced by vegetation and play important roles in global carbon efflux and nutrient cycling under global changes. Coniferous and broadleaved forests are two phyletically distinct vegetation types. Soil microbial communities in these forests have been extensively investigated but few studies have presented comparable data regarding the characteristics of bacterial communi...
متن کاملPlant Diversity and Richness in Relation to Environmental Gradient in Zagros Ecosystems, West of Iran
Plant diversityis essential to maintain the health of planet's ecosystems. Conservation of biodiversity is necessary for the ecological stability and productivity in natural ecosystems. The aim of this research was to study the biodiversity and richness of plant species (including trees, shrubs and grasses) related to the environmental factors (soil and physiography) in the forests of Zagros, w...
متن کاملInteractive effects of disturbance and nitrogen availability on phosphorus dynamics of southern Appalachian forests
Understanding the main and interactive effects of chronically altered resource availability and disturbance on phosphorus (P) availability is increasingly important in light of the rapid pace at which human activities are altering these processes and potentially introducing P limitation. We measured P pools and fluxes in eighteen mixed forest stands at three elevations (low, mid, high) subjecte...
متن کاملTree growth, foliar chemistry, and nitrogen cycling across a nitrogen deposition gradient in southern Appalachian deciduous forests
The declining health of high-elevation red spruce (Picea ruhens Sarg.) and Fraser lir (Abies fraseri (Pursh) Poir.) in the southern Appalachian region has long been linked to nitrogen (N) deposition. Recently. N deposition has also been proposed as a source of negative health impacts in lower elevation deciduous forests. In 1998 we established 46 plotc on six sites in North Carolina and Virgini...
متن کاملSoil N2O fluxes along an elevation gradient of tropical montane forests under experimental nitrogen and phosphorus addition
Nutrient deposition to tropical forests is increasing, which could affect soil fluxes of nitrous oxide (N2O), a powerful greenhouse gas. We assessed the effects of 35–56 months of moderate nitrogen (N) and phosphorus (P) additions on soil N2O fluxes and net soil N-cycling rates, and quantified the relative contributions of nitrification and denitrification to N2O fluxes. In 2008, a nutrient man...
متن کامل