Tuo Hanghang, Ghanizadeh Hossein, Ji Xiuyun, Yang Mengru, Wang Zilin, Huang Jiandi, Wang Yibo, Tian Huihui, Ye Faming, Li Wei
College of Soil and Water Conservation Science and Engineering, Northwest A&F University, Yangling 712100, China.
College of Horticulture and Landscape Architecture, Northeast Agricultural University, Haerbin 150030, China.
Sci Total Environ. 2024 Dec 20;957:177781. doi: 10.1016/j.scitotenv.2024.177781. Epub 2024 Nov 29.
Grassland community diversity plays a vital role in maintaining the functionality of grassland ecosystems, influencing processes such as nutrient cycling and supporting ecosystem multifunctionality (EMF). Long-term fencing impacts biodiversity and nutrient dynamics, but its effects alongside grazing practices are not well understood. This study examined grazing intensity's effects on community structure, leaf traits, diversity, and ecosystem functions in a 38-year-fenced grassland, through a four-year grazing experiment. Kansu red deer (Cervus elaphus kansuensis) was chosen due to its diverse diet, tolerance to rough feeding, and high feed conversion efficiency. Results showed that grazing intensity significantly affected community structure. Moderate grazing promoted perennial grasses and legumes, boosting aboveground biomass, while heavy grazing encouraged poisonous forbs, potentially harming ecosystem health. Moderate grazing also enhanced diversity metrics such as the Shannon-Weiner index, species richness, functional richness, and functional diversity. Additionally, it improved leaf traits like community-weighted mean leaf nitrogen, phosphorus content, specific leaf area, and leaf dry matter content, all contributing to better EMF. Structural equation modeling revealed that EMF was directly influenced by grazing intensities and indirectly through changes in leaf traits and taxonomic diversity. These findings suggest that moderate grazing enhances EMF in long-term fenced grasslands by improving the distribution of functional groups, leaf traits, and community diversity. Thus, moderate grazing is an optimal strategy for maintaining community diversity and EMF, highlighting the importance of grazing management for sustainable land use and addressing ecological challenges in grassland ecosystems.
草原群落多样性在维持草原生态系统功能方面发挥着至关重要的作用，影响着养分循环等过程并支持生态系统多功能性（EMF）。长期围栏会影响生物多样性和养分动态，但其与放牧方式共同产生的影响尚不清楚。本研究通过一项为期四年的放牧实验，考察了放牧强度对一片围栏38年的草原上群落结构、叶片性状、多样性和生态系统功能的影响。选择甘肃马鹿（Cervus elaphus kansuensis）是因其食性多样、耐粗饲且饲料转化效率高。结果表明，放牧强度显著影响群落结构。适度放牧促进了多年生草本植物和豆科植物生长，提高了地上生物量，而重度放牧则有利于有毒杂草生长，可能损害生态系统健康。适度放牧还提高了多样性指标，如香农 - 维纳指数、物种丰富度、功能丰富度和功能多样性。此外，它改善了叶片性状，如群落加权平均叶片氮含量、磷含量、比叶面积和叶片干物质含量，所有这些都有助于更好地实现生态系统多功能性。结构方程模型显示，生态系统多功能性直接受到放牧强度的影响，并通过叶片性状和分类多样性的变化间接受到影响。这些发现表明，适度放牧通过改善功能群分布、叶片性状和群落多样性来增强长期围栏草原的生态系统多功能性。因此，适度放牧是维持群落多样性和生态系统多功能性的最佳策略，凸显了放牧管理对可持续土地利用和应对草原生态系统生态挑战的重要性。
