城市化地区河岸带植物多样性特征及其与滨河用地性质的关系——以晋江市九十九溪为例

Characteristics of riparian plant diversity and its relationship with land use in urbanization area——a case of Jiushijiu River in Jinjiang City,Fujian Province

以晋江市的九十九溪为研究对象,通过划分河段进行采样调查与影像数据提取,并采用多样性指数、土地利用指数等进行数据处理分析,研究了河岸带植被多样性及其变化规律.结果表明:九十九溪河岸带植被物种构成是以草本植物为主,草本植物的多样性指数高于乔灌木,均匀度指数低于乔灌木,草本植物种间数量的分配更加广泛与稳定,比乔灌木更能抵御外界的干扰.九十九溪草本植物的均匀度低于灌木植物,灌木植物的均匀度指数低于乔木植物,表明在人为干扰比较强的城市化地区,河岸植物群落的自然梯度变化与演替已不再是影响群落的构成与结构的主要因素.不同河段植被景观风貌所具有的自然格调与其存留的乡愁景观要素与河段属性状况协同对应,乡村、农田河段与工业区、城区河段相比,受外来植物的影响相对较少,能够更好地保持自然植被景观风貌,具有地带特色的乡愁景观要素依然存在.从总体土地格局层面上看,城镇化地区河流空间异质性对植物多样性存在胁迫,建设用地类型越多,对生物多样性胁迫越大,特别是城市建设用地的出现致使生物多样性大幅下降.

Jiushijiu River in Jinjiang City was selected as research target,which was divided into nine sections based on such factors as its eco-environment,landscape,land use and city functions. In each section,sample survey was conducted while video data were collected. All the information was processed and analyzed by using the diversity index and land use index so as to gain a better understanding of the diversity of riparian vegetation as well as its changes. The research results were as follows: herb predominated in riparian vegetation with a higher diversity index and a lower evenness index compared with shrub. Herb species were distributed more evenly than shrub species,and possessed a stronger ability to withstand external interference. In Jiushijiu River,the evenness index of herbs was lower than that of shrubs,which was lower than that of arbors. This demonstrated that the natural gradient change and succession of riparian vegetation were not a key factor to influence its composition or structure in the urban area greatly interfered by humans. The natural style of vegetation landscape and its nostalgic scenery matched with the characteristic of a specific section of creeks. Compared with industrial and urban areas,the rural area were not greatly influenced by the plants from outside. Therefore,the rural area well-preserved natural vegetation landscape,where local nostalgic scenery still remained. According to the land pattern in a holistic manner,the spatial heterogeneity of rivers in urban areas threatened vegetation diversity. The more types of construction sites there were,the more greatly threatened the biological diversity were. Especially urban construction sites gave rise to a sharp decline of biological species.