Time for recovery of riparian plants in restored northern Swedish streams: a chronosequence study

A lack of ecological responses in stream restoration projects has been prevalent throughout recent literature with many studies reporting insufficient time for recovery. We assessed the relative importance of time, site variables, and landscape setting for understanding how plant species richness and understory productivity recover over time in riparian zones of northern Swedish streams. We used a space-for-time substitution consisting of 13 stream reaches restored 5–25 years ago, as well as five unrestored channelized reference reaches. We inventoried the riparian zone for all vascular plant species along 60-m study reaches and quantified cover and biomass in plots. We found that while species richness increased with time, understory biomass decreased. Forbs made up the majority of the species added, while the biomass of graminoids decreased the most over time, suggesting that the reduced dominance of graminoids favored less productive forbs. Species richness and density patterns could...

近年来的相关研究普遍指出，河流修复项目难以产生预期的生态响应，诸多研究认为修复后生态恢复所需时间不足。本研究针对瑞典北部溪流的河岸带，评估了时间、生境变量与景观背景在解释植物物种丰富度和林下生产力随时间恢复过程中的相对重要性。本研究采用空间替代时间法（space-for-time substitution），选取了13个修复于5至25年前的河段，以及5个未修复的渠化对照河段。我们在60米长的研究河段内对河岸带的所有维管植物（vascular plant）物种进行了调查，并在样地中量化了植被盖度与生物量。研究结果显示，尽管物种丰富度随修复后时间推移而上升，林下生物量却呈下降趋势。新增物种以非禾本草本植物为主；而随时间推移，禾本科草本（graminoids）的生物量下降幅度最大，这表明禾本科草本优势度的降低，为生产力较低的非禾本草本植物提供了生存优势。物种丰富度与密度的分布模式可……