赣江中游水源涵养林乔木和蕨类植物凋落物持水和失水特征

选取赣江中游典型水源涵养林中常见的3种常绿针叶树、3种落叶阔叶树、4种常绿阔叶树和5种蕨类植物的凋落叶,通过室内浸泡试验和失水试验研究了植物凋落物的持水和失水特征.结果表明:(1)凋落物的吸水速率均显示出随浸泡时间增加而降低的趋势,到8 h基本趋于平缓,24 h达到饱和状态,而失水速率随着失水时间的增加逐渐减少,到12...

Litter Water-holding and Water-loss Characteristics of Trees and Ferns in the Water Conservation Forests at the Middle Reaches of the Gan River

In this study, we collected leaf litter of three evergreen coniferous trees, three deciduous broadleaf trees, four evergreen broadleaf trees, and five ferns in the water conservation forests at the middle reaches of the Gan River, and compared the interspecific differences in litter water-holding and water-loss characteristics using the laboratory soaking and water loss experiments. The results showed that, for all species, litter water absorption rate showed a decreasing trend with soaking time in the initial 8 hours, and then did not change with soaking time. Similarly, litter water loss rate decreased with water loss time in the initial 12 hours, and then remained constant. After 24 hours of soaking, fern (202.5%) had higher litter saturated water holding capacity than deciduous broadleaf trees (173.0%), evergreen broadleaf trees (124.6%), and evergreen coniferous trees (86.5%). In addition, both deciduous broadleaf trees (65.4%) and ferns (65.4%) had higher litter water loss capacity than evergreen broadleaf trees (53.6%) and evergreen coniferous trees (42.8%). Both saturated water holding capacity and mean water loss rate of leaf litter were negatively correlated with the initial litter tissue density (R²=0.428 and 0.266, respectively), but positively correlated with the initial specific leaf area (R²=0.488 and 0.398, respectively). These results indicated that litter tissue density and specific leaf area were the important factors controlling the interspecific variations of water-holding and water-loss capacity of leaf litter among plant functional groups. Our observations highlight the importance of understory fern litter to forest water conservation function, which would be helpful to the future evaluation of ecosystem services and development of management practices in the water conservation forests at the middle reaches of the Gan River.