干旱区生态环境知识资源中心

The relationship between the number of species and the area sampled is one of the oldest and best-documented patterns in community ecology. An equation of the form S = cA(z) describing more precisely the species-area relation for plant species in smaller area is proposed as a result of intensive examination of species presence. Several study and field data from a wild range of plant and animal taxa suggest that the slope, z, of a graph of the logarithm of species richness against the logarithm of area is not a constant to the grassland or woodland community. We collected replicated and randomized plant data at 6 spatial scales from 1 m(2) to 1 km(2) in the desert region of northwest China to identify the scale dependence in desert plant biodiversity. The results showed that the slope of the log-log plot varied systematically with spatial scale. The value of z was high (0.37) at small scales from 1 to 10 m(2) and it decreased with increased spatial scale subsequently. When spatial scales varied from 1 m(2) to 1 km(2), the value of z varied from 0.37 to 0.035, suggesting that desert plant diversity has strongly scale-dependence at the small scales (less than 100 m(2)). The result is different from the research of grassland and woodland communities.