摘要
水杉(Metasequoiaglyptostroboides)是我国特有濒危极小种群物种,其种群的状态一直被国内外学者广泛关注。分析现存水杉原生种群结构和空间分布格局及其空间关联性,可以从空间格局角度深入认识水杉原生种群结构和分布格局及可能的形成机理。本文基于湖北利川境内水杉原生种群的野外调查数据,分析其径级和高度级结构,同时运用点格局分析中的成对相关函数g(r)以及3个零模型(完全空间随机模型、异质泊松模型、先决条件模型)分析水杉原生种群空间分布格局、各龄级空间分布格局及空间关联性。结果表明:(1)分布于研究区域内的水杉原生种群个体数共5,663株,已死亡33株,现存活5,630株,其中40株濒临死亡,465株处于衰弱状态,部分个体呈现不同的形态特征和生长状况,断梢和蚁害最为常见,雷击是最致命的危害。(2)水杉原生种群结构分析显示,其径级结构和高度级结构均呈纺锤型,自然更新不良。(3)基于完全空间随机模型,水杉原生种群在各尺度下均呈现聚集分布,中龄树在较小尺度(r<3,300 m)上呈现聚集分布,成年树和老龄树在较大尺度(r<4,700 m)上呈现聚集分布;排除生境异质性影响后,聚集尺度均减小,所以种群及不同龄级的聚集尺度分别为0–3,000 m、0–2,100 m、0–2,900m和0–2,500 m,随后呈现为微弱的随机分布和均匀分布。(4)基于完全空间随机模型,3个龄级之间在所有尺度均为正关联;在排除生境异质性影响后,不同龄级的正关联尺度减小,均在0–2,800 m呈正关联。综上,水杉原生种群个体数量正呈现逐步减少的趋势,种群主要呈聚集分布,各个龄级间具有正向的关系,从现有的空间格局来看,生境异质性、扩散限制和种内竞争是导致该格局的主要原因。
Metasequia glyptostroboides is an endemic and endangered species in China,and has therefore been heavily researched.M.glyptostroboides’distribution seems to have a recognizable spatial pattern,with a clear potential mechanism.To test this,we analyzed the structure and diameter classes and height level classes from survey data of parent M.glyptostroboides trees with a pairwise correlation function g(r)and three null models(complete spatial randomness,heterogeneous Poisson process,and antecedent condition)in a point pattern analysis.The results of the spatial distribution patterns showed that:(1)There was 5,661 individuals of the native M.glyptostroboides population in the study area.Within this population,31 of which were dead,40 trees were on the verge of death,and 465 trees were classified as"weak",with morphological characteristics and growth conditions associated with these trees such as shoot breakage,ant damage,and lightning strike.(2)Both the diameter-class structure and the height-class structure were spindle-shaped,with poor natural renewal;(3)Based on Complete Spatial Randomness,the native M.glyptostroboides population showed a random distribution at all scales,the middle-aged trees showed an aggregation distribution on a small scale(r<3,300 m),and the adult trees and the older trees appeared an aggregation distribution on a larger scale(r<4,700 m).The aggregation scales of the population and the different age groups were 0–3,000 m,0–2,100 m,0–2,900 m and 0–2,500 m,respectively,and followed a weak random distribution and uniform distribution.(4)Based on Complete Spatial Randomness,there were positive correlations between the three growth stages at all scales that weakened when habitat heterogeneity was excluded(only a positive correlation between 0–2,800 m).In summary,the M.glyptostroboides population is decreasing gradually with poor population regeneration.The population is presented mainly as cluster distribution with positive relationship among all age classes,due to habitat heterogeneity,diffusion limitation and intra-species competition according to the existing spatial pattern.
作者
黄小
朱江
姚兰
艾训儒
王进
吴漫玲
朱强
陈绍林
Xiao Huang;Jiang Zhu;Lan Yao;Xunru Ai;Jin Wang;Manling Wu;Qiang Zhu;Shaolin Chen(School of Forestry ami Horticulture,Hubei Minzu University,Enshi,Hubei 445000;Key Laboratory of Biological Resources Protection and Utilization of Hubei Province,Hubei Minzu University,Enshi,Hubei 445000;Hubei Xingdoushan National Nature Reserve Administration,Enshi,Hubei 445000)
出处
《生物多样性》
CAS
CSCD
北大核心
2020年第4期463-473,共11页
Biodiversity Science
基金
国家重点研发计划(2016YFC0503100)
湖北省自然科学基金(2019CFB229)
湖北省“双一流”建设专项资金和湖北民族大学博士启动基金(MY2018B027)。
关键词
水杉原生种群
种群结构
点格局分析
空间关联性
Metasequoia glyptostroboides
population structure
point pattern analysis
space correlation
