OALib Journal期刊

ISSN: 2333-9721



匹配条件: “Chimner” ,找到相关结果约3条。
Restoring sedges and mosses into frost heaving iron fens, San Juan Mountains, Colorado
R.A. Chimner
Mires and Peat , 2011,
Abstract: Rare iron fens in the San Juan Mountains of Colorado are frequently in poor condition due to mining, roads and ditches, which have left much of the fen completely bare of vegetation. Natural revegetation is slow to occur in the bare areas because of severe frost heave in the cold mountain climate. Therefore, experimental revegetation plots were conducted in a factorial design with mulching and no mulching, crossed with moss diaspores, sedge transplants, and moss and sedge combined. Mulching influenced surface soil temperatures by reducing the midday highs and increasing the night-time lows, which decreased the frequency and amount of frost heave. Peat moisture also modified frost heave, with the greatest frost heaving occurring near 75 % peat moisture content (water table 10–20 cm below the surface) and the least when soils were either wetter or drier. Moss survival was dependent on mulch, with no moss surviving in plots without mulch. Mulching also increased sedge transplant survival. In summary, mulching significantly increased the success of vegetation restoration efforts for frost heave areas in mountain fens.
Long-term carbon accumulation in two tropical mountain peatlands, Andes Mountains, Ecuador
R.A. Chimner,J.M. Karberg
Mires and Peat , 2008,
Abstract: Tropical peatlands form in at least two distinct altitudinal zones, namely lowlands and high mountains. Unlike lowland tropical peatlands, which are typically forested, tropical mountain peatlands are dominated by cushion plants, bryophytes and herbaceous plants. Tropical mountain peatlands are poorly understood and little information is available on their ages, whether their peat bodies are relicts or actively accumulating carbon, the amount of carbon they contain, or the rate at which they can accumulate carbon. Our objective in this paper is to quantify carbon accumulation rates in two peatlands in the Andes Mountains of Ecuador, South America. At each site, we collected peat cores which were analysed for bulk density, mineral content and % C and we calculated the amount of carbon stored. Due to the high amount of mineral sediment in the Cotopaxi peatland, carbon dating was not done at this site. The Cayambre-Coca peat body was 4 m thick, ca. 3,000 years old, and had accumulated 140 kgC m-2. The approximate long-term rate of carbon accumulation (LARCA) is 46 gC m-2 yr-1. However, a significant part of the depth of accumulation is due to high levels of mineral sediment input from steep side slopes and volcanic ash input.
Ecohydrological conditions of wetlands along a precipitation gradient in Patagonia, Argentina
Chimner,Rodney A; Bonvissuto,Griselda L; Cremona,M Victoria; Gaitan,Juan J; López,Carlos R;
Ecolog?-a austral , 2011,
Abstract: wetlands are an important component of the andean ecology because of their wealth of biodiversity and endemisms, and the many environmental services they offer. however, baseline knowledge of the types of wetlands and their ecohydrological functioning is currently lacking. therefore, the objective of this study was to characterize the types and the ecohydrological conditions of wetlands along a precipitation gradient in the northern patagonian andes. this study took advantage of a strong precipitation gradient that occurs due to the rain shadow effect created by the andes mountains near the city of san carlos de bariloche. we selected five representative wetlands that are at similar elevations and latitudes, but under very different precipitation regimes. at each site, we sampled water and soil chemistry, water levels and floristic composition. we found that hydrological, chemical and vegetation parameters all varied with total precipitation. sphagnum peatlands occurred in the wettest regions and had year round water saturated soils which formed a peat layer. meadows were common in the driest regions. we sampled three distinct meadow communities: wet meadows with juncus balticus, mesic meadows with festuca pallescens and salt meadows with distichlis spicata each with a distinct hydrological regime, water chemistry and floristic composition. marsh/shrub wetlands occurred in the intermediate rainfall areas and had standing water, mineral soils and were vegetated by nothofagus antarctica and scirpus spp. our results indicate the importance of precipitation on wetland structure and function and suggest that any change in precipitation regime will cause significant changes to these ecosystems.

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