针对海南岛耕地撂荒形成的草地无序放牧较为普遍的现象,以不同放牧方式(轮牧和连续放牧)、不同放牧强度(重度、中度和轻度)进行草地放牧试验,利用多光谱无人机和植被冠层分析仪,获取放牧期间日尺度草地叶面积指数(Leaf area index,LAI)...针对海南岛耕地撂荒形成的草地无序放牧较为普遍的现象,以不同放牧方式(轮牧和连续放牧)、不同放牧强度(重度、中度和轻度)进行草地放牧试验,利用多光谱无人机和植被冠层分析仪,获取放牧期间日尺度草地叶面积指数(Leaf area index,LAI)信息,定量分析不同放牧策略对草地叶面积指数及牧牛行为变化的影响。研究结果表明:(1)中度放牧条件下的轮牧有利于草地LAI的提升。重度放牧时,轮牧和连续放牧草地的LAI上升的区域占草地总面积的比例分别为3.21%和12.65%;中度放牧时,轮牧和连续放牧草地的LAI上升的区域占草地总面积的比例分别为52.01%和25.83%;轻度放牧时,轮牧和连续放牧草地的LAI上升的区域占草地总面积的比例分别为61.02%和60.37%。(2)重度放牧条件下,牛的采食时间占比始终最高,随着采食时间占比的增加,草地LAI的减少量也随之增加,但当采食时间占比增加至70.88%~73.42%时,草地LAI的减少量逐渐降低。此时,草地叶面积指数下降到初始状态(第一天啃食前)的79.60%~79.90%,即牛的啃食量已经到达了草地LAI当日能够供给的极限,当超过这个极限时,草地可食用牧草大幅减少,牲畜个体采食竞争加剧,同时牛的啃食行为时间占比大大提高。研究结果有助于优选出牧场尺度下最佳的草畜管理措施,为热带草地畜牧系统的可持续发展从新的角度提供理论方法和决策支撑,助力国家生态文明试验区(海南)的建设。展开更多
Aims Ecological strategies related to the adaptation of plants to environmental stress have long been studied by ecologists,but few studies have systematically revealed the ecological process of plant adaptation to he...Aims Ecological strategies related to the adaptation of plants to environmental stress have long been studied by ecologists,but few studies have systematically revealed the ecological process of plant adaptation to herbivores as a whole.Methods In this study,Stipa breviflora,the dominant species in the desert steppe of Inner Mongolia,was used to analyse its reproductive individual characteristics and seed traits as well as the soil seed bank and spatial patterns under heavy-grazing and no-grazing treatments.Important Findings The results showed that the number of reproductive branches positively affected the number of vegetative branches.The analysis of the soil seed bank showed that the density of S.breviflora seeds beneath reproductive S.breviflora individuals was significantly higher than that in bare land.The seed density was also significantly negatively correlated with the seed characteristics and the soil seed bank in bare land.The spatial distribution of S.breviflora was aggregated under heavy grazing.Our results suggest that under heavy grazing,reproductive activity plays a key role in resource allocation.Stipa breviflora evolved the ecological strategy of nearby diffusion by regulating the morphological characteristics of the seeds,which promotes a positive spatial correlation between the juvenile and adult populations at a small scale,thus leading to the formation of‘safe islands’.展开更多
文摘针对海南岛耕地撂荒形成的草地无序放牧较为普遍的现象,以不同放牧方式(轮牧和连续放牧)、不同放牧强度(重度、中度和轻度)进行草地放牧试验,利用多光谱无人机和植被冠层分析仪,获取放牧期间日尺度草地叶面积指数(Leaf area index,LAI)信息,定量分析不同放牧策略对草地叶面积指数及牧牛行为变化的影响。研究结果表明:(1)中度放牧条件下的轮牧有利于草地LAI的提升。重度放牧时,轮牧和连续放牧草地的LAI上升的区域占草地总面积的比例分别为3.21%和12.65%;中度放牧时,轮牧和连续放牧草地的LAI上升的区域占草地总面积的比例分别为52.01%和25.83%;轻度放牧时,轮牧和连续放牧草地的LAI上升的区域占草地总面积的比例分别为61.02%和60.37%。(2)重度放牧条件下,牛的采食时间占比始终最高,随着采食时间占比的增加,草地LAI的减少量也随之增加,但当采食时间占比增加至70.88%~73.42%时,草地LAI的减少量逐渐降低。此时,草地叶面积指数下降到初始状态(第一天啃食前)的79.60%~79.90%,即牛的啃食量已经到达了草地LAI当日能够供给的极限,当超过这个极限时,草地可食用牧草大幅减少,牲畜个体采食竞争加剧,同时牛的啃食行为时间占比大大提高。研究结果有助于优选出牧场尺度下最佳的草畜管理措施,为热带草地畜牧系统的可持续发展从新的角度提供理论方法和决策支撑,助力国家生态文明试验区(海南)的建设。
基金supported by the Qinghai Provincial Key R&D Program in Qinghai Province(2019-SF-145)the Platform of the Adaptive Management of the Alpine Grassland-livestock System(2020-ZJ-T07)+1 种基金the Natural Science Foundation for Young Scientists of Qinghai Province(2018-ZJ-939Q)the National Natural Science Foundation of China(31460126,3177131141).
文摘Aims Ecological strategies related to the adaptation of plants to environmental stress have long been studied by ecologists,but few studies have systematically revealed the ecological process of plant adaptation to herbivores as a whole.Methods In this study,Stipa breviflora,the dominant species in the desert steppe of Inner Mongolia,was used to analyse its reproductive individual characteristics and seed traits as well as the soil seed bank and spatial patterns under heavy-grazing and no-grazing treatments.Important Findings The results showed that the number of reproductive branches positively affected the number of vegetative branches.The analysis of the soil seed bank showed that the density of S.breviflora seeds beneath reproductive S.breviflora individuals was significantly higher than that in bare land.The seed density was also significantly negatively correlated with the seed characteristics and the soil seed bank in bare land.The spatial distribution of S.breviflora was aggregated under heavy grazing.Our results suggest that under heavy grazing,reproductive activity plays a key role in resource allocation.Stipa breviflora evolved the ecological strategy of nearby diffusion by regulating the morphological characteristics of the seeds,which promotes a positive spatial correlation between the juvenile and adult populations at a small scale,thus leading to the formation of‘safe islands’.
