北京怀九河河岸类型的植被与土壤理化性质差异

植被和土壤作为组成河岸带生态系统的重要因素,其空间分布与变异对河岸带生态功能起着决定性作用.以北京市怀九河河岸带为研究对象,在基于60个样地调查的基础上,对植被数量特征和多样性,以及土壤理化性质进行调查与分析,并对比了自然型(15个)、近自然型(25个)和人工型(20个)3种典型河岸植被与土壤理化性质的差异性.结果表明:1)河岸带植被组成以草本占绝大多数(占总物种数的79.22％),而乔木与灌木种类分布较少,且不同河岸类型下的植被多样性指数差异性显著(P＜0.05),自然型河岸植物多样性(4.6±0.16)以及丰富度指数(7.26±0.40)要明显大于近自然型(3.82±0.16、6.36±0.32)以及人工型河岸(3.94±0.18、5.40±0.42)(P＜0.05),表现为干扰下的河岸带生境不断退化.2)随干扰程度的增加,土壤质量不断下降,且土壤质地、密度和土壤有机质质量分数在不同河岸类型条件下,差异性显著(P＜0.05);其中,土壤有机质质量分数(％)分布表现为自然型(4.88±0.43)＞近自然型(3.47±0.31)＞人工型(1.92±0.15)(P＜0.05),土壤密度(g/cm3)分布表现为自然型(1.18±0.03)＜近自然型(1.35±0.03)＜人工型(1.52±0.03) (P ＜0.05).3)植被多样性与土壤理化性质间具有潜在的相关性;其中,植被的均匀度指数与土壤有机质质量分数显著正相关(P＜0.05),植被丰富度指数与土壤密度极显著负相关(P＜0.01)、与土壤总孔隙度显著正相关(P＜0.05),而植被物种多样性指数与土壤理化指标间相关性不显著.该研究不仅说明干扰条件影响植被与土壤间紧密的相关性,也为北京山区河岸带生态系统恢复与重建,提供基础信息和理论依据.

Vegetation and soil physicochemical properties in different types of the Huaijiu River riparian in Beijing

Background] As an important component of riparian ecosystem,vegetation and soil are closely related to the biodiversity,stability,nutrient filter in riparian.To date,however,there are few studies about the spatial variation of the riparian vegetation communities and soil physicochemical properties under different types of riparian.Methods] The study was carried out in the Huaijiu River,southwest of Huairou district,Beijing.According to the extent of disturbance and development status of riparian zones,we divided it into three types (natural type,near-natural type,and artificial type).Then,based on the survey of 15 natural type plots,25 near-natural type plots and 20 artificial type plots,we investigated the vegetation diversity and the soil physicochemical properties and compared them between different riparian types.Results] Vegetation diversity and soil physicochemical characteristics were significantly different in different types of riparian.The vegetation composition in the riparian of the Huaijiu River was mainly herbs,accounting for 79.22％ of the total number of species,and of species diversity (4.6 ±0.16) and species richness index (7.26 ±0.40) of the natural type riparian was greater than the near-natural type (3.82 ±0.16 and 6.36 ±0.32) and the artificial type (3.94 ±0.18 and 5.40 ±0.42) (P ＜ 0.05);The soil quality showed a degradation trend with increasing magnitude of disturbances.The soil organic matter content of the natural riparian (4.88 ± 0.43％) was higher than the near-natural riparian (3.47 ±0.31％) and artificial riparian (1.92 ±0.15％) (P ＜0.05).The soil bulk density of the natural type was lower (1.18 ± 0.03 g/cm3) than near-natural riparian (1.35 ± 0.03 g/cm3),and the soil bulk density of artificial riparian was the highest,which was matter content (P ＜0.05),while the richness index was negatively correlated with soil bulk density (P ＜ 0.01) and positively correlated with soil total porosity (P ＜ 0.05).Conculsions] The results showed that the correlation relationship between vegetation and soil was influenced by human disturbances.It provides a theoretical basis for the restoration and reconstruction of riparian ecosystem in Beijing mountain area.