摘要
木本植物幼苗是高山林线生态交错区的重要组成部分,其更新对气候变化背景下树线的移动至关重要.本研究通过对近几十年来全球范围内林线生态交错区的木本植物幼苗分布特征、更新机制及其对气候变化响应的研究总结得出:林线生态交错区木本植物幼苗的空间分布类型主要为渐变型和聚集型,且不同分布类型对树线动态的指示意义各异.在全球尺度上,其分布的海拔高限通常与生长季长度、均温和物种特性等有关,而在区域尺度上则多受降水影响.在幼苗更新初期,种源在很大程度上决定了种子的萌发及分布位置,之后微环境的促进作用为幼苗的定植提供庇护,提高其存活率,而在更新后期多种生物和非生物因素及其相互作用则非常关键.气候变暖促使林线生态交错区气温升高、降水充沛,有利于幼苗生长,使其向高海拔区域扩张而成为树线上移的先兆,但部分物种受遗传特性或适应策略影响,仅表现为密度增加,使树线保持相对稳定.未来应借助树轮、14C等精确定年技术,通过长期的野外定位观测和室内模拟,加强多时空尺度下林线幼苗的空间分布特征和更新机制研究,分析不同类型林线内木本植物幼苗的适应策略,预测气候变化背景下的树线动态,为山地生态系统恢复及保护提供科学依据.
Tree seedlings are one of the important components in alpine treeline ecotone,whose regeneration is crucial to treeline migration in response to climate change.We analyzed the spatial distribution,regeneration of tree seedlings and their responses to climate change in treeline ecotone in recent decades.The spatial distribution of tree seedlings in treeline ecotone is dominated by diffuse and clustered forms,with different indicative significance for spatial dynamics of treeline.At global scale,the altitude distribution limits of tree seedlings are usually related to the length and average temperature of growing season,along with the species characteristics.However,precipita-tion plays an important role at regional scale.The initial stage of seedling recruitment is restricted by seed source,which determines seed distribution and germination to a great extent.Microenvironment facilitates seedling regeneration by providing shelter for establishment and improving their survival rate.The regeneration process is more relevant to multiple biotic,abiotic factors and their interactions.With global warming,rising temperature in treeline ecotone and more precipitation are more suitable for seedling regeneration of treeline species.The expansion of seedlings to higher elevations could be considered as the portent of timberline upwards migration.Due to species-specific adaption strategy,however,some trees only increase seedling density and timberline location is constant.In the future,it is necessary to take precise dating techniques,such as tree-ring and 14C dating,and conduct long-term in-situ monitoring and indoor simulation experiments.To provide scientific basis for mountain ecosystem restoration and conservation,we should strengthen the studies on spatial patterns and regeneration mechanism of seedlings in treeline ecotone at multiple spatio-temporal scales,the adaptation strategies of tree seedlings in different types of treeline ecotone and treeline dynamics prediction.
作者
邵佳怡
杜建会
李升发
黄一鑫
梁伟诺
廖家强
SHAO Jia-yi;DU Jian-hui;LI Sheng-fa;HUANG Yi-xin;LIANG Wei-nuo;LIAO Jia-qiang(School of Geography and Planning,Sun Yat-sen University,Guangzhou 510275,China;Guangdong Key Laboratory for Urbanization and Geo-simulation,Guangzhou 510275,China;Guangdong Open Laboratory of Geospatial Information Technology and Application,Guangzhou Institute of Geography,Guangzhou 510070,China)
出处
《应用生态学报》
CAS
CSCD
北大核心
2019年第8期2854-2864,共11页
Chinese Journal of Applied Ecology
基金
国家自然科学基金项目(41101011)
广东省自然科学基金项目(2018A030313936)
广东省科学院实施创新驱动发展能力建设专项(2018GDASCX-0903,2016GDASRC-0101,2019GDASYL-0302001)资助~~
关键词
林线生态交错区
树线
木本植物幼苗
空间分布特征
更新机制
环境胁迫
气候变化
treeline ecotone
treeline
tree seedling
spatial distribution characteristics
regeneration mechanism
environment stress
climate change
