| Resource & environmental sciences |
|
|
|
|
| Structure and dynamics of herbaceous layer vegetation of artificial Caragana intermedia shrublands in desert steppe. |
| Zhao Wei, Yang Mingxiu, Chen Lin, Wang Lei, Song Naiping, Yang Xinguo* |
| (Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China/Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in North-western China of Ministry of Education, Ningxia University, Yinchuan 750021, China) |
|
|
|
Abstract Caragana intermedia is a leguminous shrub plant, which is planted in desert steppe area on a large scale, which can also be used as forage grass, with very important ecological and economic value. However, a series of shrub and grass resource competition problem emerged with the aging of C. intermedia shrublands. The growth of zonal perennial vegetation often subjected to great constraints, and self-degradation of C. intermedia shrublands was also developed to different degrees. The reasonable collocation relations of shrub and grass were one of the key elements to maintain ecology and production services of C. intermedia shrublands in desert steppe. The objective of this study is to understand composition characteristics of herbaceous plant species and its dynamic change rules around the C. intermedia shrublands, and to reveal the structure of shrub and grass and the evolution trend of C. intermedia shrubland system. Taking natural grassland as a control, spatiotemporal substitution methods were used, and a research sequence constituted of different ages of C. intermedia shrubland plots was erected to carry out tracking, monitoring and analysis of vegetation seasonal dynamics at interior and exterior of the shrubs. The results showed that: 1) The number of natural grassland (CK) and herbaceous plant species of C. intermedia shrublands were 25 species, belonging to 8 families and 23 genera. The highest species number was the 16 a C. intermedia shrublands (16 species), and the number of species gradually decreased with aging of C. intermedia shrublands. Pennisetum centrasiaticum, Cleistogenes squarrosa and other perennial grasses began to appear, but the dominant species still was short-lived annual plants. Species diversity indexes showed a decreasing trend after a steady increase with aging of C. intermedia shrublands. 2) The seasonal dynamics, coverage degree, aboveground biomass and species number of herbaceous layer vegetation were mainly affected by the change of precipitation and temperature, but the existence of C. intermedia shrubs delayed the growth recovery rate of herbaceous layer vegetation after spring drought, and the highest relative volatility index was 25 a C. intermedia shrublands. 3) The coverage degree of herbaceous layer vegetation at the interior and exterior of the C. intermedia shrubs and the seasonal dynamics of aboveground biomass at the interior of the C. intermedia shrubs were significantly changed by the ages of C. intermedia shrubland, and a significant interaction between ages of C. intermedia shrublands and seasonal factors was observed.
|
|
Published: 20 November 2015
|
|
|
荒漠草原人工柠条林草本层植被的结构与动态
为系统认识柠条林草本层植被的物种组成特征及其动态变化规律，把握灌草结构及人工林系统的演变趋势，采用空间换时间的方法，以天然草地为对照，搭建一个由不同林龄样地构成的研究序列，并开展灌丛内外植被季节性动态的跟踪监测与分析。结果表明:1）对照草地和柠条林地草本层物种共计25种，分属于8个科23个属。16 a柠条林物种数最多（16种），随着林龄的增大，物种数逐渐减少，中亚白草和隐子草等多年生禾草开始出现，但是优势种以一年生短命植物为主。物种多样性指数则随林龄增长呈先增长后下降的趋势。2）草本层植被盖度、生物量与物种数的季节动态主要受降水、气温变化的影响，但是灌丛的存在显著延滞了草本层植被经历春季干旱后的生长恢复速度，并以25 a柠条林的生长节律变化最为突出。3）林龄显著改变了灌丛内外草本层植被盖度以及灌丛内草本层植被生物量的季节动态，林龄与季节因子间存在显著的交互作用。综上所述，荒漠草原人工柠条林草本层植被的结构与动态是林龄、季节以及空间异质性等因子交互作用下的产物，伴随人工柠条林的衰败，群落存在逐步向地带性植被演替的趋势，但是在以一年生短命植物为主要优势物种情况下，系统稳定性的维持和演替方向还存在诸多的不确定性。
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
| |
Shared |
|
|
|
|
| |
Discussed |
|
|
|
|
