摘要
物种丰富度格局及其决定因素是生态学核心问题,但对其形成机制仍缺乏共识。为探究松嫩平原西部半干旱区沿湖岸至高地环境梯度(局地尺度)植物群落多样性分布格局及其决定因素,以沿该梯度依次分布的7种群落(狭叶香蒲沼泽、小香蒲沼泽、芦苇沼泽、草丛沼泽、拂子茅草甸、羊草草甸和榆树疏林)为对象,采用样带网格调查法及聚类分析法划分群落类型,测定物种丰富度、α多样性和β多样性及其环境因子(水位、土壤含水率、有机质等),揭示群落多样性空间分布规律及其形成机制。结果表明,沿湖岸至高地环境梯度:(1)物种丰富度(2.00—18.00)和α多样性(Simpson指数0.12—0.90;Shannon-Wiener指数0.23—2.57和Pielou指数0.34—0.88)总体上均呈类似N字型分布(在下部深水生境狭叶香蒲沼泽最低、中下部季节性积水生境草丛沼泽最高、中上部湿润生境拂子茅草甸较低、上部沙丘干旱生境榆树疏林又较高);(2)广义的β多样性(Jaccard指数0.56—0.96)可以分解成物种周转(丰富度没有变化的地点间的物种替代)和嵌套(物种贫乏地点是物种丰富地点子集时的物种差异)两个过程,其在该梯度上半段干旱生境和下半段浅水生境相对较高,且主要由周转过程控制。在常年积水生境上最低且仅由嵌套过程控制,而在环境梯度中间地段则由周转和嵌套过程共同控制;(3)物种丰富度和α多样性的主控因子沿该梯度发生了明显转换,在高水位区由水位、有机质和全磷共同控制;中水位区仅由速效磷控制;低水位区由pH和含水率控制。因此,松嫩平原半干旱区沿湖岸至高地环境梯度物种丰富度和α多样性存在明显的空间分布格局及具有较高的β多样性,且其主要形成机制为微地形创造局地空间环境异质性与物种库相互作用共同塑造了植物群落多样性,故在生物多样性管理实践中应对其空间分布格局完整性加以重点保护。
Patterns and determinants of species richness are the central issues in ecology,but there is still a lack of consensus on their formation mechanisms.In order to explore the distribution patterns and determinants of community diversity along lakeshore-highland environmental gradient(local scale)in western Songnen Plain semi-arid region,species richness,α diversity,β diversity and environmental factors including water level(WL),soil water content(WC),organic matter(OM),etc.were measured by setting up sample belts and cluster analysis in seven communities(Typha angustifolia wetland,Typha minima wetland,Phragmites australis wetland,hassock wetland,Calamagrostis epigeios meadow,Leymus chinensis meadow and elm sparse forest)along this gradient,to reveal the spatial variation and formation mechanisms of community diversity.The results show that,along lakeshore-highland environmental gradient:(1)both species richness(2.00—18.00)andαdiversity(Simpson index 0.12—0.90;Shannon-Wiener index 0.23—2.57 and Pielou index 0.34—0.88)showed a similar N-shaped distribution pattern(Typha angustifolia wetland was the lowest at the lower deep-water habitats,hassock wetland was the highest at the lower-middle seasonal inundated habitat,the lower at the middle-upper wet habitats of Calamagrostis epigeios meadow and the higher at the upper arid habitats of dune elm sparse forest).(2)We partitioned the generalizedβdiversity(Jaccard index 0.56—0.96)into two components:species turnover(species replacement among sites without changes in richness)and nestedness(species differences among sites when species-poor sites constitute subsets of those with a greater number of taxa).β diversity was relatively high at arid habitats located in upper half and shallow-water habitat located in lower half of the gradient,and it was mainly controlled by turnover processes.At the permanently inundated habitats,it was the lowest one,which is controlled only by nestedness processes.But in the middle of the environmental gradient,the turnover and nestedness processes control it togther.(3)The main controlling factors of species richness andαdiversity were significantly converted along the gradient.The high water level area was jointly controlled by water level,organic matter and total phosphorus(TP),the medium water level area was controlled only by available phosphorus(AP)and the low water level area was jointly controlled by pH and water content.Therefore,there were obviously spatial distribution patterns of species richness andαdiversity,and higher β diversity along lakeshore-highland environmental gradient in the Songnen Plain semi-arid region.Our results suggested that the main mechanism was the interaction between the local spatial environmental heterogeneity created by microtopography and the region species pool,which jointly shaped the plant community diversity.Thus,its spatial distribution patterns integrity should be protected in the practice of biodiversity management.
作者
梁道省
牟长城
高旭
鲁艺
LIANG Daosheng;MU Changcheng;GAO Xu;LU Yi(Center for Ecological Research,Northeast Forestry University,Harbin 150040,China)
出处
《生态学报》
CAS
CSCD
北大核心
2023年第1期339-351,共13页
Acta Ecologica Sinica
基金
中央高校自主科研项目计划(2572019DF07)。
关键词
松嫩平原半干旱区
植物群落
Α多样性
Β多样性
湖岸至高地环境梯度
semi-arid area of Songnen Plain
plant community
αdiversity
βdiversity
lakeshore-highland environmental gradient
