施肥对科尔沁沙质草地群落物种组成和多样性的影响

以科尔沁沙质草地为对象,研究了施肥对科尔沁沙质草地群落物种组成、群落结构和多样性的影响。结果表明,1)施氮肥和氮磷肥混施均改变了群落物种组成、群落中的优势种以及植物的科属结构,显著增加了群落植被高度和盖度,其中施氮肥和氮磷肥混施比对照的植被高度均提高了64.5和66.8cm,植被盖度分别提高17.1%和18.1%。2)施磷肥对群落物种组成和群落结构影响不显著。3)施氮肥和氮磷肥混施均显著减小了沙质草地群落的Shannon-Wiener指数、Simpson指数、Pielou均匀度指数和物种丰富度,其中施氮肥和氮磷肥混施分别减少物种数49.5%和51.5%。4)施磷肥对群落物种数和各物种多样性指数均无显著影响。表明除了生产力,合理的物种组成和群落结构也是受损草地生态系统恢复和经营需要考虑的因素。

Effects of fertilizations on species composition and diversity of grassland in Keerqin Sandy Lands

Effects of different fertilization on species composition, community structure and species diversity of grassland were studied in Keerqin Sandy Lands. 1) Species composition, dominant species and family structure of the species of grassland communities were changed both by nitrogen fertilizer (N) alone and by nitrogen plus phosphorus fertilizers (N+P). Nitrogen and N+P significantly (P<0.05) increased vegetation height and coverage by 64.5 and 66.8 cm, and by 17.1% and 18.1%, respectively. 2) Phosphorus fertilizer alone (P) did not significantly change species composition or community structure. 3) Species richness, Shannon-Wiener index, Simpson index and Pielou evenness index were also significantly (P<0.05) improved by N and N+P. Nitrogen and N+P markedly reduced species richness by 49.5% and 51.5%. 4) P did not significantly change species number and diversity of sandy grassland. The results suggest that, in addition to productivity, reasonable species composition and community structure are considerations for the process of restoring and managing degenerated grassland ecosystems.