He Xiaole, Yuan Li, Wang Zhen Hong, Zhou Zizong, Wan Li
Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region, Ministry of Education, Chang'an University, Xi'an, Shanxi, China.
School of Water and Environment, Chang'an University, Xi'an, Shanxi, China.
PeerJ. 2020 Oct 19;8:e10226. doi: 10.7717/peerj.10226. eCollection 2020.
Anthropogenic disturbance and distinctive geochemistry have resulted in rocky desertification in many karst regions of the world. Seed banks are crucial to vegetation regeneration in degraded karst ecosystems characterized by a discontinuous distribution of soil and seasonal drought stress. However, the dynamics of seed banks across one complete series of secondary succession and the underlying mechanisms remain unclear. We selected eight typical stages during secondary succession, conducted aboveground vegetation survey and collected 960 soil samples in the Guiyang karst landscape of China. Seed density, species richness and plant life forms in seed banks were determined via the germination method. The results indicated that the seed density in seed banks before and after field seed germination was significantly different among most succession stages. Community succession had impacts on the seed density of seed banks before and after field seed germination. Seed density ranged from 1,042 seedlings.m in evergreen broadleaf forests to 3,755 seedlings.m in the herb community, which was a relatively high density. The seed density and similar species composition between the seed banks and vegetation declined with succession from early to later stages. Species richness in seed banks was highest in middle succession stages and increased with increasing species richness of aboveground vegetation. The species richness of the five life forms in the seed banks showed different variations across these succession stages. The conservation of diverse aboveground vegetation can maintain the diversity of seed banks for restoration.
人为干扰和独特的地球化学特征导致了世界上许多喀斯特地区的石漠化。种子库对于退化喀斯特生态系统中的植被恢复至关重要，这些生态系统的特点是土壤分布不连续且存在季节性干旱胁迫。然而，整个次生演替系列中种子库的动态变化及其潜在机制仍不清楚。我们在中国贵阳喀斯特地貌的次生演替过程中选择了八个典型阶段，进行了地上植被调查，并采集了960个土壤样本。通过发芽法测定种子库中的种子密度、物种丰富度和植物生活型。结果表明，在大多数演替阶段，田间种子萌发前后种子库中的种子密度存在显著差异。群落演替对田间种子萌发前后种子库的种子密度有影响。种子密度从常绿阔叶林的1042株/m到草本群落的3755株/m不等，这是一个相对较高的密度。随着演替从早期到后期的进行，种子库与植被之间的种子密度和相似物种组成下降。种子库中的物种丰富度在演替中期最高，并随着地上植被物种丰富度的增加而增加。种子库中五种生活型的物种丰富度在这些演替阶段呈现出不同的变化。保护多样的地上植被可以维持种子库的多样性以促进恢复。
