The shift in the abundance of two Stipa species in response to land use change is associated with their divergent reproductive strategies  

作　　者：Xiaoshuai Wang Frank Yonghong Li Yuanheng Li Xin Song Xudong Guo Xiangyang Hou Taogetao Baoyin 

机构地区：[1]Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau&Inner Mongolia Key Laboratory of Grassland Ecology,School of Ecology and Environment,Inner Mongolia University,Hohhot 010021,China [2]Grassland Research Institute of the Chinese Academy of Agricultural Sciences,Hohhot 010020,China

出　　处：《Journal of Plant Ecology》2019年第4期722-729,共8页植物生态学报（英文版）

基　　金：The research was supported by the Ministry of Science and Technology of China(grant no.2016YFC0500508,2015BAC02B04,2014CB138802);the Department of Science and Technology of Inner Mongolia Autonomous Region of China(Grant for Key Basic Research Project on Grassland Ecosystems).

摘　　要：Aims The divergent changes of plant species under land use changes are key mechanisms underlying vegetation succession.Stipa grandis steppe and Stipa krylovii steppe are two plant commu-nities widely distributed on the Mongolian Plateau.They have been speculated to be able to succeed into each other under different land use types and intensities based on the observa-tions on their presence and abundance at the sites with dif-ferent land use history.However,no direct evidence,neither the underlying mechanisms,have been reported for this specu-lation.Here,we verified this speculation and explored the underlying mechanisms in the typical steppe region of Inner Mongolia.Methods We investigated the abundance and reproductive behavior of S.kry-lovii and S.grandis under different land use types and intensities.We used 18 grassland paddocks to run a 6-year experiment with 6 management treatments(T0-unused,T1-grazing monthly in plant growing season,T2,T4,T6-grazing in different months in plant growing season,and T8-mowing)replicated three times.We measured the relative density and cover of S.krylovii and S.grandis using line sampling method and examined their number and bio-mass of vegetative and reproductive tillers using quadrat method in each paddock after treatments for 4 and 6 years.We also de-termined these plant attributes in 14 pairs of heavily versus lightly used grassland plots in a wide area(150 km×200 km)of the typical steppe region.Important Findings 1.Grazing largely and mowing moderately decreased the density ratio and coverage ratio of S.grandis to S.krylovii in grasslands(P<0.05),and the differences in these ratios between grazed and unused grasslands increased with time.2.Grazing,but not mowing,significantly enhanced the relative density(N_(rep)=reproductive tiller number/total tiller number)of,and biomass allocation(B_(rep)=reproductive tiller biomass/total bio-mass)to,reproductive tillers of S.krylovii(P<0.05),but not S.gran-dis.This grazing enhancement to sexual reproduction of S.krylovii,and additio

关 键 词：reproductive tiller vegetative tiller SUCCESSION GRAZING MOWING 

分 类 号：S81[农业科学—畜牧学]