Spatial Patterns of Plant Diversity in Chinese Forest Ecosystems

Spatial patterns of plant diversity along with longitude,latitude and altitude for tree,shrub and herb layers in forest ecosystems were investigated by using the data collected at 10 ecological stations of Chinese National Ecosystem Research Network( CNERN). Indices for plant diversity included species richness index( Patrick index),diversity index( Shannon-Wiener index,Simpson index) and evenness index( Pielou index). The results showed that along latitude from south to north in China,the species richness index of shrub plants and trees in forests decreased but no general change pattern was found for herbaceous plants. The diversity index for trees decreased at first and then increased with latitude. Along longitude from east to west in China,the species richness index of trees,shrubs and herbs tended to decrease. For diversity indices( Shannon-Wiener index and Simpson index),tree layer decreased at first and then increased,whereas shrubs exhibited an opposite tendency,and herbs showed no general change pattern. The evenness index was found to be similar with diversity index in three layers. With increasing altitude,the species richness index increased at first and then decreased for trees,shrubs and herb with a peak value at low-elevations,and the diversity index( Shannon-Wiener Index and Simpson index) of trees showed the similar trend with the species richness indix,whereas no general trend was found for both shrubs and herbs.