Deforestation of watersheds of Panama: nutrient retention and export to streams
Deforestation of watersheds of Panama: nutrient retention and export to streams
复制标题
巴拿马流域的森林砍伐：养分保留和向溪流的输出
DOI：
10.1007/s10533-013-9836-2
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发表时间：
2013
期刊：
影响因子：
4
通讯作者：
M. Bartholomew
中科院分区：
文献类型：
--
作者：
I. Valiela;Coralie Barth;T. Stone;J. Crusius;S. Fox;M. Bartholomew
在巴拿马太平洋沿岸的一系列八个流域，通过手工焚烧将成熟的低地湿林转化为牧场，为流域尺度的试验单位提供了广泛的森林覆盖率（23%、29%、47%、56%、66%、73%、73%、91%和92%）。我们利用这些流域作为景观尺度的实验来评估森林砍伐程度对流域内保持和大气养分输入的水文输出的影响。截留量是通过比较降雨养分浓度（考虑到蒸散作用的体积加权）与接收溪流淡水河段的浓度来估计的。在这些巴拿马流域，雨水产生的营养物质的滞留率平均分别为硝酸盐、铵、溶解有机氮和磷酸盐的77%、85%、80%和62%。然而，降雨产生的无机氮的滞留取决于流域覆盖：在牧场为主的流域中，硝酸盐和铵的滞留率分别为95%和98%，而完全森林覆盖的流域保留了65%和80%的大气硝酸盐和铵输入。流域森林覆盖不影响溶解有机氮和磷酸盐的滞留。森林覆盖较多的流域出口DIN/P接近16，而牧场为主的流域出口N/P接近2。出口规模和比例的差异表明，这些巴拿马森林的毁林导致了出口，影响了接收河流和河口生态系统中植物和藻类的生长。通过湿和干大气沉降计算的溶解无机氮的流域滞留量分别从牧场的90%到森林主导的流域的65%不等。因此，从流域接收水域排放的DIN从牧场为主的流域大气输入的10%上升到完全森林化的流域大气输入的35%左右。这些结果来自没有农业或城市化的流域，但通过燃烧将森林转化为牧场的不同方式，表明热带流域内具有重要的、依赖于森林砍伐的保留率，但也具有重要的生态意义和依赖于森林砍伐的出口，由于接收热带溪流和沿海水域的营养物质缺乏而具有重要的生物学意义。
A series of eight watersheds on the Pacific coast of Panama where conversion of mature lowland wet forest to pastures by artisanal burning provided watershed-scale experimental units with a wide range of forest cover (23, 29, 47, 56, 66, 73, 73, 91, and 92 %). We used these watersheds as a landscape-scale experiment to assess effects of degree of deforestation on within-watershed retention and hydrological export of atmospheric inputs of nutrients. Retention was estimated by comparing rainfall nutrient concentrations (volume-weighted to allow for evapotranspiration) to concentrations in freshwater reaches of receiving streams. Retention of rain-derived nutrients in these Panama watersheds averaged 77, 85, 80, and 62 % for nitrate, ammonium, dissolved organic N, and phosphate, respectively. Retention of rain-derived inorganic nitrogen, however, depended on watershed cover: retention of nitrate and ammonium in pasture-dominated watersheds was 95 and 98 %, while fully forested watersheds retained 65 and 80 % of atmospheric nitrate and ammonium inputs. Watershed forest cover did not affect retention of dissolved organic nitrogen and phosphate. Exports from more forested watersheds yielded DIN/P near 16, while pasture-dominated watersheds exported N/P near 2. The differences in magnitude of exports and ratios suggest that deforestation in these Panamanian forests results in exports that affect growth of plants and algae in the receiving stream and estuarine ecosystems. Watershed retention of dissolved inorganic nitrogen calculated from wet plus dry atmospheric deposition varied from 90 % in pasture- to 65 % in forest-dominated watersheds, respectively. Discharges of DIN to receiving waters from the watersheds therefore rose from 10 % of atmospheric inputs for pasture-dominated watersheds, to about 35 % of atmospheric inputs for fully forested watersheds. These results from watersheds with no agriculture or urbanization, but different conversion of forest to pasture by burning, show significant, deforestation-dependent retention within tropical watersheds, but also ecologically significant, and deforestation-dependent, exports that are biologically significant because of the paucity of nutrients in receiving tropical stream and coastal waters.
影响因子：
5.2
作者：
Boy, Jens;Rollenbeck, Ruetger;Wilcke, Wolfgang
通讯作者：
Wilcke, Wolfgang