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Inner Mongolia Agricultural University (2020)

Plant and Soil Spatial Patterns of Main Species in Stipa Breviflora Desert Steppe in Response to Stocking Rates

熊梅;

Titre : Plant and Soil Spatial Patterns of Main Species in Stipa Breviflora Desert Steppe in Response to Stocking Rates

Auteur : 熊梅;

Grade : Doctoral Dissertation 2020

Université : Inner Mongolia Agricultural University

Résumé partiel
Desert steppe is a kind of grassland with the strongest arid nature from steppe to desert.The habitat of the desert steppe ecosystem was fragmented due to long-term overgrazing and utilization,and the spatial distribution pattern of plants has changed,which often presents as patchy distribution.Studying the effect of grazing on the changing characteristics of spatial patterns of plants and soil,and their interaction rules is of great significance for understanding the succession mechanism of grassland communities.The experiment plots within the Stipa breviflora desert grassland were selected and fenced to establish a grazing trial which with four different stocking rates treatments(Control,CK ;lightly grazed,LG ;moderately grazed,MG and heavily grazed,HG).This research were mainly conducted on two aspects :(1)Exploring the response of species diversity(alpha diversity)to stocking rates at the community level and to discuss the spatial pattern characteristics of the four major species(constructive species:Stipa breviflora,dominants species:Artemisia frigida and Cleistogenes songorica,main companion species Convolvulus ammannii)and soil carbon and nitrogen,and the relationship between the plant characters and soil heterogeneity by using the method of spatial pattern analysis,niche width and overlap,spatial autocorrelation,semivariance analysis and kriging map ;(2)The effects of stocking rates on species composition,species turnover and diversity from patches which were mainly composed of the selected four main species were studied by using alpha and beta diversity index.The seasonal dynamics and coupling relationship of plant-root-soil carbon and nitrogen contents were also studied for the main species from each patch.It aims to reveal the response of plant and soil spatial patterns and the nutrient coupling relationship response to grazing disturbance at the level of community and population(patch),and to clarify the differences and causes of the change of grassland ecosystem spatial pattern caused by long-term grazing,which would provide a scientific basis for formulating a reasonable grazing system and sustainable development of natural grasslands

Mots clés : Stocking rates; Spatial pattern; Desert steppe; Patch; Heterogeneity;

Présentation (CNKI)

Page publiée le 15 juin 2021, mise à jour le 26 octobre 2021