Mosla hangchowensis Matsuch is an annual herb, which is found only on the s
eacoast of Zhejiang province in southeast China. The species has declined i
n numbers and is now endangered. The survival ratio, seminal power, reprodu
ctive success ratio, and density as: well as other factors were measured fr
om 1993 to 1996, and an existence analysis was performed. There are two env
ironmental sieves during the life history of this species, and the survival
curve is between the Deevey-I and Deevey-II. A constant proportion of indi
viduals died throughout the life cycle. The optimum niche of M. hangchowens
is is a habitat with soil depth 20-30 cm, with moderate to slightly wet con
ditions, with neither too intense nor too shaded light. The realized niche
now is on the top of rocky hills or along gravel roadsides. Sites: are few
and dispersed. Loss of the optimum niche and a decrease of realized habitat
s as a result of human activities, the disparity between the realized niche
and the optimum, and a low dispersal ability of populations are currently
contributing to the endangerment of M. hangchowensis.