不同土地利用方式对典型温性草原群落物种组成和多样性以及生产力的影响

摘要

This article discusses the community differences including community composition, species diversity and productivity between six land use and manage patterns (fenced Stipa grandis lawn, fenced Leymus chinen-sis lawn, public grazing lawn, private grazing lawn, fired and fenced S. grandis lawn and artificial forage) in a typical tempered grassland in Xinlin Gol. The comparison was aimed to find out and to understand the influences and their mechanism that grassland use methods would bring to the community. Results were obtained by community investigation, and measurement of aboveground biomass and belowground biomass using harvest method and soil auger method in each plots. The above and below ground biomass decreased in grazed communities, and significantly increased in long-term fenced communities (P<0. 05); but being fenced or not didn't remarkably affect the community composition or species diversity. With the weakening of the grassland usage, the productivity and proportion of C3 plants gradually increased (P<0. 05), the productivity of C4 plants remained steady and its proportion decreased. The past fire raised the species diversity and productivity and proportion of the C4 plant in the community in the grassland communities (P<0. 05), significantly reduced the below ground biomass (P<0. 05) , and increased, but had rarely effect on the above ground biomass. The forage reclamation of grassland severely changed the community composition, significantly reduced the below ground biomass, but largely raised the above ground biomass, consequently resulting in higher the above/below ground biomass ratio compared to any surrounding natural grassland communities.%以锡林郭勒典型温性草原区域不同利用、管理方式植物群落作为研究对象,选取当地较为常见的6种不同利用管理方式围封禁牧大针茅,围封禁牧羊草,公共放牧大针茅、私人放牧大针茅、大针茅火烧围封恢复和开垦人工饲草的典型草地设置实验样地,采用群落调查、收割称重和根钻取样等方法测定、比较上述群落的物种组成、物种多样性和生产力构成.结果表明放牧降低大针茅群落的地上、地下生物量,而长时间的围封显著增加群落的地上地下生产力(P＜0.05),但对群落物种组成和物种多样性影响不大(P＞0.05).随着利用程度的减弱,群落C3植物生产力和所占比重逐渐上升(P＜0.05),C4植物生物量保持稳定(P＞0.05),但比例下降(P＜0.05).火烧显著增加群落物种多样性(P＜0.05),同时显著降低地下生物量(P＜0.05),但地上生物量变化不大,同时C4植物生物量显著上升.人工开垦极大改变了群落的物种组成,同时显著增加群落地上生物量,降低群落地下生物量,使群落获得了相对天然群落更高的地上生物量/地下生物量.