Can the Regeneration of Vegetation from Riparian Seed Banks Support Biogeomorphic Succession and the Geomorphic Recovery of Degraded River Channels?
Can the Regeneration of Vegetation from Riparian Seed Banks Support Biogeomorphic Succession and the Geomorphic Recovery of Degraded River Channels?
复制标题
河岸种子库的植被再生能否支持生物地貌演替和退化河道的地貌恢复？
DOI：
10.1002/rra.2778
复制
发表时间：
2015
影响因子：
2.2
通讯作者：
M. Leishman
中科院分区：
文献类型：
--
作者：
J. O’Donnell;K. Fryirs;M. Leishman
对于因侵蚀和河道拓宽而退化的河流，重建河岸植被至关重要。我们评估的潜力河岸种子银行，以促进自然渠道收缩，通过再生的植物参与三个离散的地貌单位的年龄和高度增加以上的通道床：酒吧，长凳和河漫滩的geomorphic演替。常设植被上的每个单元类型进行了调查，在澳大利亚东部的猎人集水区的四个河流河段。种子库的组成，确定使用出苗技术从单位采样的沉积物。比较了现存植被和种子库物种的物种丰富度、组成、寿命、生长形态和种子传播机制。种子银行是类似的酒吧，长凳和河漫滩，主要是多年生先锋草本植物，莎草和灯心草，分散风和水媒（水运输）。沙坝植被类似于种子库，而阶地和河漫滩植被包括较晚的演替物种，如灌木和乔木，明显更多的草和藤本植物（阶地：χ25，N = 402 = 102.033，p < 0.001;河漫滩：χ25，N = 792 = 30.324，p < 0.001），无辅助和动物分散种子的比例较高（阶地：χ25，N = 352 = 89.409，p < 0.001;河漫滩：χ25，N = 338 = 56.026，p < 0.001）。结果表明，种子库可能支持早期阶段的演替，通过先锋植物的再生。然而，在河床（即阶地和洪泛区）以上年龄和高度不断增加的单位上观察到的植物，如灌木和树木，可能来自当地植被产生的瞬时种子，而不是种子库。版权所有© 2014约翰威利父子有限公司.
For rivers degraded by erosion and channel widening, the re‐establishment of riparian vegetation is essential. We assess the potential for riparian seed banks to facilitate natural channel contraction through the regeneration of plants involved in the biogeomorphic succession of three discrete geomorphic units of increasing age and height above the channel bed: bars, benches and floodplain. Standing vegetation upon each unit type was surveyed for four river reaches in the Hunter catchment of eastern Australia. Seed bank composition was determined using seedling emergence techniques on sediment sampled from the units. We compared species richness and composition, and longevity, growth form and seed dispersal mechanisms between the standing vegetation and seed bank species. The seed bank was similar across bars, benches and floodplain, containing mostly perennial pioneer herbs, sedges and rushes, dispersed by wind and hydrochory (water transport). While bar vegetation was similar to the seed bank, bench and floodplain vegetation included later successional species such as shrubs and trees, significantly more grasses and vines (benches: χ25, N = 402 = 102.033, p < 0.001; floodplain: χ25, N = 792 = 30.324, p < 0.001) and higher proportions of unassisted and animal‐dispersed seeds (benches: χ25, N = 352 = 89.409, p < 0.001; floodplain: χ25, N = 338 = 56.026, p < 0.001). The results suggest that seed banks may support early stages of biogeomorphic succession, via regeneration of pioneer plants. However, plants, such as shrubs and trees that are observed upon units of increasing age and height above the channel bed (i.e. benches and floodplain), are likely sourced from transient seeds produced by local vegetation, rather than seed banks. Copyright © 2014 John Wiley & Sons, Ltd.