不同生态恢复措施下宁夏黄土丘陵区典型草原植物群落数量分类和演替

进行植物群落数量分类和演替研究对退化草地生态恢复具有重要意义。以宁夏黄土丘陵区典型草原为对象,借助植被数量生态学方法,对封育、水平沟和鱼鳞坑3种生态恢复措施实施0(1年)、3、6、10和15年下的草地植物群落进行了数量分类,研究了群落演替序列及其与土壤因子的关系。结果表明:(1)应用双向指示种(TWINSPAN)结合除趋势对应分析(DCA),将研究样地植物群落类型划分为8个。(2)封育0~15年,植被演替序列为本氏针茅+百里香群落→本氏针茅+大针茅群落→百里香+本氏针茅群落→本氏针茅+大针茅群落→本氏针茅+铁杆蒿群落;水平沟和鱼鳞坑整地后1年到15年,植被演替序列分别为沙打旺+白草群落→早熟禾+赖草群落→本氏针茅+百里香群落→百里香+赖草群落→本氏针茅+大针茅群,沙打旺+白草群落→早熟禾+本氏针茅群落→本氏针茅+百里香群落→百里香+本氏针茅群落;随着恢复年限增加,鱼鳞坑和水平沟措施下植物优势物种变化总趋势是根茎型—疏丛型—密丛型植物,但也存在非线性或螺旋式的变化; 3种恢复措施下,植物群落盖度和地上生物量随恢复年限增加呈上升趋势,其中封育草地增加速度最快,鱼鳞坑最慢。(3)除趋势典范对应分析(DCCA)表明,土壤容重、有机质、真菌、全磷和蛋白酶是影响该区植物群落分布的主要土壤因子。

Floristic quantitative classification and successional characteristics of typical grassland under different ecological restoration methods in the Loess Hilly Region of Ningxia

Restoration measures strongly influence vegetation communities.To design effective restoration measures for the Loess Hilly Region,it is important to classify the flora and study the succession of degraded grassland plant communities on the typical steppe in Ningxia.In this study,we explored the relationship between the plant succession process and soil factors under three ecological restoration measures (enclosure,contour trench,and fish-scale pits) implemented for 0 (1),3,6,10 and 15 years by using Two Indicators Species Analysis (TWINSPAN) combined with a detrended correspondence analysis (DCA).The main results were as follows:(1) According to the TWINSPAN-DCA,the vegetation in the study plot was divided into eight communities.(2) With increasing exclosure time,the vegetation succession sequence was as follows:Stipa bungeana + Thymus mongolicus communities→S.bungeana + Stipa grandis communities→ T.mongolicus + S.bungeana communities→S.bungeana + S.grandis communities→S.bungeana + Artem isia sacrorum communities.The succession process from 1 to 15 years in the contour trench grassland was as follows:Astragalus adsurgens + Pennisetum flaccidum communities→Poa annua + Leym us secalinus communities→S.bungeana + T.mongolicus communities→T.mongolicus+L.secalinus communities→S.bungeana+S.grandis communities.The succession process from 1 to 15 years in the fish-scale pits grassland was as follows:A.adsurgens +P.flaccidurn communities→P.annua+S.bungeana communities→S.bungeana+T.mongolicus communities→T.mongolicus+S.bungeana communities.In the contour trench grassland and the fish-scale pits grassland,the trend in the dominant vegetation type over time was rhizome type-sparse type-dense cluster type,but there were also non-linear or spiral changes.The coverage of the plant community and aboveground biomass increased over time under all three restoration measures,and the growth rate was fastest in enclosed grassland and slowest in the fish-scale pits grassland.(3) The results of a detrended canonical correspondence analysis indicated that soil bulk density,organic matter,fungi,total phosphorus,and protease activity are the main soil factors affecting the vegetation communities in this area.