Species diversity in a Casuarina equisetifolia understory along a highway
To analyze changes in roadside ecological factors, in growth of Casuarina equisetifolia, and in un-derstory species diversity with coastal highway construction, three parallel line transects perpendicular to the west side of Jinjiang Coastal Highway and 200 m apart were selected. Light intensity, air temperature, relative humidity, soil bulk density, and soil moisture content were monitored at sample points along the transects. Results indicated that (1) the highway's zone of influence for light intensity was up to 100 m and for other ecological factors (air temperature, relative humidity, soil bulk density, and soil moisture content) was up to about 50 m. Highway influence decreased as the distance from the highway increased. (2) Tree height, DBH, and crown area of C. equisetifolia were significantly greater (P < 0.01) in undisturbed areas than in roadbed disturbance areas. (3) As distance from the highway increased, shade-requiring plants gradually replaced pho-tophilous plants with the herb and plant understory changing to shrubs with a uniform distribution. Dominant species changed most 50-100 m from the highway. (4) As distance from the highway increased, understory species diversity increased gradually and then stabilized with the species turnover rate being maximum at 50-100 m from the highway. (5) The strongest biodiversity influence on the C. equisetifolia trees due to the highway was concentrated in the 0-100 m range with a gradual decrease as the distance from the highway in- creased.
国家科技期刊平台
NSTL
万方数据
维普
