Search

Pervious pavement of large parking lot in sponge city is a new structural form, which is conducive to solving the problem of deterioration of urban ecological environment. The hydrological characteristics of large permeable parking lot are studied. The results show that the effect of large permeable parking lot on flow delay is obvious. No runoff occurs in the structure of large permeable parking lot when the maximum rainfall intensity reaches 0.968 mm/min. When the recurrence period increases from one year to 100 years, the percentage of total runoff reduction are 100%, 66%, 56%, 48%, 44%, and the peak flow reduction rate are 100%, 58%, 50%, 46%, 41%, respectively. With the extension of rainfall recurrence period, the total amount of runoff reduction in large permeable parking lots increased, and the reduction rate showed a downward trend. The research results can provide reference for the construction of large permeable parking lot in sponge city.

Cycas debaoensis Y.C.Zhong et C.J.Chen is a rare and endangered cycad species that is endemic to South China. It has divided pinnae. Genetic variation in the species was investigated by using an intersimple sequence repeat (ISSR) marker. The species exhibits a moderate level of genetic diversity (at population level P = 34.7%, H = 0.141, I = 0.204; at species level P = 57.4%, H = 0.215, I = 0.315) and a high level of genetic differentiation among populations (Gst = 0.342). Thus, the indirect estimate of gene flow on the basis of Gst was low (Nm = 0.481). The narrow colonisation area and island pattern of distribution, combined with limited gene flow among populations and genetic drift, may play an important role in shaping the genetic structure of C. debaoensis. On the basis of these findings, strategies are suggested for the conservation and management of the species.