How hydrology, habitat type, and litter quality affect leaf breakdown in wetlands on the Gulf Coastal Plain of Georgia
How hydrology, habitat type, and litter quality affect leaf breakdown in wetlands on the Gulf Coastal Plain of Georgia
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水文、栖息地类型和凋落物质量如何影响乔治亚州墨西哥湾沿岸平原湿地的叶子分解
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
S. Golladay
中科院分区：
文献类型：
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作者：
J. Battle;S. Golladay
自20世纪70年代以来，格鲁吉亚西南部的年径流量显著减少，季节性降雨模式发生了变化（即，稍潮湿的冬天和干燥的春天），对湿地的叶片分解过程的影响。在四个独立的研究年（1999-2002年），我们研究了两种类型的森林湿地，洪泛平原和抑郁症的叶分解过程。采用相互转移设计，垃圾袋含有黑胶（尼萨syhatica biflora）和水tupelo（尼萨aquatica）被放置在三个湿地的每一种类型。我们预测开放的湿地（洪泛区）将有更快的故障率比孤立的湿地（抑郁症），和水tupelo叶收购高营养湿地（洪泛区）将是不那么难治性和分解速度比黑树胶叶从低营养湿地（抑郁症）。没有一致的模式，一个湿地类型有更快的崩溃率比其他。在八种情况中的三种情况下，水树（k =-0.57至-1.77 yr-1）的分解速度比黑树胶（k =-0.53至-1.31 yr-1）快（即，相同的湿地类型和年份）;否则，没有发现物种之间的差异。从干燥的年份（1999年，2000年和2001年）的结果表明，凋落物种类是更重要的比湿地类型在确定P水平的凋落物，在某些情况下，N浓度，但在潮湿的一年（2002年）N和P的模式在凋落物不同的湿地类型。这项多年的研究使我们能够得出结论，在干旱的年份，水分水平主要影响有机物的分解，但在多年的长期洪水，更快的分解率发生在湿地类型和凋落物物种具有较高的营养水平。一个1.4至3倍的研究年（相同的湿地类型和凋落物）之间的分解率的差异表明，应谨慎使用，根据一个单一的分解研究的结论。
Since the 1970s, southwestern Georgia has seen significant decreases in annual stream flows and changes in seasonal rainfall patterns (i.e., slightly wetter winters and drier springs) that have implications for leaf breakdown processes in wetlands. In four separate study years (1999–2002), we examined leaf breakdown processes in two types of forested wetlands, floodplain and depressional. Using a reciprocal transfer design, litter bags containing black gum (Nyssa syhatica biflora) and water tupelo (Nyssa aquatica) were placed in three wetlands of each type. We predicted open wetlands (floodplain) would have faster breakdown rates than isolated wetlands (depressional), and water tupelo leaves acquired from high-nutrient wetlands (floodplain) would be less refractory and decompose faster than black gum leaves obtained from low-nutrient wetlands (depressional). There was no consistent pattern of one wetland type having faster breakdown rates than the other. Breakdown of water tupelo (k = −0.57 to −1.77 yr−1) was faster than black gum (k = −0.53 to −1.31 yr−1) in three out of eight instances (i.e., same wetland type and year); otherwise, no difference was detected between species. Results from the drier years (1999, 2000, and 2001) suggest that litter species was more important than wetland type in determining P levels in litter and in some instances N concentrations, but in the wetter year (2002) N and P patterns in litter differed by wetland type. This multiyear study allowed us to conclude that in drought years, moisture levels primarily influenced breakdown of organic matter, but in years with prolonged flooding, faster breakdown rates occurred in the wetland type and litter species with the higher nutrient levels. A 1.4 to 3-fold difference in breakdown rates among study years (for the same wetland type and litter) suggest that caution should be used in making conclusions based on a single decomposition study.