Natural or assisted succession as approach of forest recovery on abandoned lands with different land use history in the Andes of Southern Ecuador
Natural or assisted succession as approach of forest recovery on abandoned lands with different land use history in the Andes of Southern Ecuador
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DOI：
10.1007/s11056-017-9590-8
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发表时间：
2017-06
期刊：
影响因子：
2.2
通讯作者：
Ximena Palomeque;S. Günter;D. Siddons;P. Hildebrandt;B. Stimm;N. Aguirre;Ruth Arias;M. Weber
中科院分区：
文献类型：
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作者：
Ximena Palomeque;S. Günter;D. Siddons;P. Hildebrandt;B. Stimm;N. Aguirre;Ruth Arias;M. Weber
在厄瓜多尔的安第斯山脉，受干扰地区的森林恢复具有特别重要的意义，因为那里的森林砍伐是一个严重的问题。自然历时演替进行了评估，在三个大的地块或网站，不同的土地利用和植被组成，一个是占主导地位的草种在废弃的牧场（Pastoris网站），其他两个是火灾后的植被占主导地位的蕨（蕨网站）和各种灌木（灌木网站）。此外，我们还评估了人工清除竞争性草本物种以加速森林恢复的有效性。在2003年，2005年和2007年进行了监测48个小区的116平方米，每个记录物种丰富度和木本物种密度。结果表明，在该地区，外来牧草对木本植物的补充具有竞争效应，但其补充量和密度均较低，表明天然林更新受到严重抑制，演替轨迹不明确。蕨和灌木网站成为显着相似的植物区系和有证据表明，一个显着的便利木本植物招聘与地面上的光可用性。这两个网站都表现出典型的演替特征，灌木表现出更高的物种丰富度和密度，而晚演替的物种是代表性很差的蕨菜网站。然而，NMDS排序使用物种密度表明，这两个轨迹可能不会收敛到一个共同的“最终状态”。人工除草对加速森林恢复无效。这些结果表明，牧场上木本物种补充的主要限制因素是强烈的草竞争，必须在种子供应之前解决，而种子供应似乎是蕨类植物和灌木地开发的限制因素，因此直播或种植可能是有效的加速森林恢复。
Forest recovery on disturbed areas is of special significance in the Ecuadorian Andes, where deforestation is a serious problem. Natural diachronic succession was evaluated on three large plots or sites, differing in their land use and vegetation composition, one is dominated by grass species on an abandoned pasture (Pasture site), the other two are post-fire vegetation dominated by bracken (Bracken site) and various shrubs (Shrub site). Additionally, we assessed the effectiveness of manual removal of competitive herbaceous species to accelerate forest recovery. Monitoring was done in 2003, 2005 and 2007 on 48 subplots of 116 m2each recording species richness and woody-species density. Results showed that the Pasture site demonstrated a competitive effect of exotic grasses on woody species recruitment with much lower species recruitment and density, suggesting serious inhibition of natural forest regeneration and an unclear successional trajectory. The Bracken and Shrub sites became significantly similar floristically and there is evidence for a marked facilitation of woody plant recruitment correlated with light availability on the ground. Both sites showed characteristics of classic succession, with Shrub showing a higher species richness and density while late-successional species are poorly represented on the Bracken site. However, NMDS ordination using species density showed that the two trajectories may not be converging towards a common “final state”. Manual weeding was ineffective for accelerating forest recovery. These results suggest that the main limiting factor for the recruitment of woody species on the Pasture site is strong grass competition and must be addressed before seed availability, while seed availability seems to be the constraining factor for Bracken and Shrub site development, thus direct seeding or planting may be effective in accelerating forest recovery.