深圳市建成区入侵植物对草本植物种类及功能多样性的影响

入侵植物对城市生态系统形成潜在威胁，有待引起足够的关注。为探究城市入侵植物对草本植物种类及功能多样性的影响，以深圳市建成区入侵植物鬼针草（Bidens pilosa）和南美蟛蜞菊（Sphagneticola trilobata）为例，分析了不同绿地类型中不同程度的单独入侵和共同入侵对草本植物群落物种多样性和功能多样性的影响规律。结果显示：①Margalef物种丰富度指数、Shannon-Wiener多样性指数、Simpson优势度指数和Pielou均匀度指数均与入侵植物盖度呈显著负相关（P<0.05，0.5865 < R² < 0.9356）。②功能丰富度指数（FRic）、功能均匀度指数（FEve）和Rao二次熵指数（FD_Q）与入侵植物盖度有一定的相关关系（0.0000 < R² < 0.2211）。③群落的特征加权平均株高（CWM_H）与入侵植物盖度有一定的正相关关系（0.0716 < R² < 0.2262）。④与未入侵的样方相比，鬼针草轻度入侵显著提高了物种多样性（P<0.05），鬼针草和南美蟛蜞菊单独重度入侵均显著降低物种多样性（P<0.05），二者各种程度的分别单独入侵及共同入侵都显著提高了群落加权平均株高（CWM_H）（P<0.05）。⑤对不同的绿地类型分开计算发现，鬼针草单独入侵和二者共同入侵都显著提高了各种绿地类型的物种多样性（P<0.05），南美蟛蜞菊单独入侵只对部分绿地类型的群落物种多样性影响显著。⑥鬼针草和南美蟛蜞菊之间的生态效应可能为拮抗作用。研究结果为进一步揭示植物入侵对城市草本植物群落的影响规律提供参考，为有效防治城市外来植物入侵提供一定的依据。

Effects of invasive plants on species and functional diversity of herbs in the built-up area of Shenzhen, China

Invasive plants potentially threaten urban ecosystems, which deserve more attention. This paper took invasive plants Bidens pilosa and Sphagneticola trilobata as a case study, to explore urban invasive plants'' influence on species and functional diversity of herbaceous plants. Different levels of independent and joint invasion effects on herbaceous community''s species diversity and functional diversity were analyzed. The results showed that:(1) Margalef species richness index, Shannon-Wiener diversity index, Simpson dominance index, and Pielou evenness index exhibited significantly negative correlation with the invasive plants'' coverage (P<0.05, 0.5865<R²<0.9356). (2) Functional richness index (FRic), Functional evenness index (FEve), and Rao''s quadratic entropy index (FD_Q) had specific correlation with the invasive plants'' coverage (0.0000<R²<0.2211). (3) Community-Weighted Mean plant height (CWM_H) had specific positive correlation with invasive plants'' coverage (0.0716<R²<0.2262). (4) Compared with the non-invasive samples, the light invasion of Bidens pilosa significantly increased the species diversity (P<0.05), but the severe independent invasion of Bidens pilosa and Sphagneticola trilobata significantly reduced species diversity (P<0.05), and all levels'' independent and joint invasions of Bidens pilosa and Sphagneticola trilobata also significantly increased CWM_H (P<0.05). (5) As found by analyzing different green space types separately, the independent and the joint invasion of Bidens pilosa both significantly increased the species diversity of all green space types (P<0.05), while Sphagneticola trilobata had no significant effect on the community species diversity. (6) The ecological effect between Bidens pilosa and Sphagneticola trilobata maybe was antagonistic. The results provide a reference for further studies on plant invasion'' effects on urban herbaceous plant communities and supply a basis for effective control of urban alien plant invasions.