Grasslands Response to Livestock Grazing Intensity in the Austral Pampas(Argentina):Testing the Intermediate Disturbance Hypothesis  

作　　者：Ana Elena de Villalobos María Andrea Long 

机构地区：[1]Grupo de Investigación en Ecosistemas de Pastizal(GIEP),CERZOS,CONICET,Bahía Blanca,8000,Argentina [2]Departamento de Biología,Bioquímica y Farmacia,Universidad Nacional del Sur,Bahía Blanca,8000,Argentina

出　　处：《Phyton-International Journal of Experimental Botany》2024年第8期2037-2050,共14页国际实验植物学杂志（英文）

基　　金：funded by CONICET(Consejo Nacional de Investigaciones Científicas y Técnicas)and SGCyT(Secretaría General de Ciencia y Tecnología,Universidad Nacional del Sur,Argentina).

摘　　要：Livestock grazing has a significant impact on natural grasslands,with approximately one-third of the world’s land area dedicated to this industry.Around 20%of global grasslands are highly degraded due to overgrazing,affecting their productivity and conservation capacity.Best practices are required to ensure sustainable livestock production that supports biodiversity.The Intermediate Disturbance Hypothesis(IDH)suggests that environments with moderate levels of disturbance exhibit a higher species diversity.Moderate grazing can reduce the dominance of certain species,thereby enhancing plant diversity.However,concerns arise regarding the increase of exotic and unpalatable species under moderate grazing levels,complicating grassland conservation efforts.The impact of livestock grazing on the functional structure of grasslands depends on factors such as grazing intensity,livestock species,and environmental conditions.Variations in grazing intensity may increase specific and functional diversity under moderate grazing,potentially masking the presence of invasive exotic species.In the Austral Pampas(Pampean phytogeographic province,Buenos Aires,Argentina),grasslands face various pressures from domestic livestock grazing that endanger their integrity if not properly managed.Therefore,our study aims to investigate potential differences in species richness and diversity,functional diversity,exotic plant abundance,and the number and distribution of plant functional groups across varying grazing intensities.The IDH is utilized as a tool to regulate livestock pressure for grassland conservation.Species and functional diversity indices were used to assess the impact of grazing on grassland diversity.Moderate grazing increased species and functional diversity,while intensively grazed or ungrazed areas showed reduced diversity.Livestock presence influenced the balance between native and exotic plants,with ungrazed areas having higher native plant abundance and grazed areas exhibiting higher exotic plant abundance.Grazing also

关 键 词：Natural grasslands grazing effects DISTURBANCE specific and functional diversity 

分 类 号：S812[农业科学—草业科学]