6. Quantitative analysis on euglenoid distribution in seven regions of China

Investigations on the qualitative and quantitative distribution of euglenoids in Jianghan Plain, Western Hubei, Wuling Mountains, Hengduan Mountains, South-eastern Xizang (Tibet), Southern Xizang and Northern Xizang show that the species composition and flora characters of the euglenoids are not very different, but the quantitative distribution varies in different regions.

1. The similarity comparisons between every two regional floras have been analysed by similarity coefficient except Northern Xizang. Most of the coefficients except a few are higher, general range in 0.6–0.7, the highest 0.81. It is reflected that there are better similarities of floras in these regions except Northern Xizang.
2. Frequency distribution for euglenoid abundance (i.e. species numbers of the euglenoids per sample) is approximate to a normal distribution in Jianghan Plain, whereas in the other regions, the distribution curves are all conspicuously exponential.
3. Regional difference: on the basis of indices of qualitative and quantitative distribution as well as of ecological factors, a cluster analysis and the Duncan multiple comparison show three distribution types of the euglenoids: (1) Jianghan Plain has the best, it differs obviously from other regions by its favourable range of natural conditions which have a warm and humid climate, low altitude and abundant rainfall etc.; (2) Northern Xizang, the least favourable type, is distinct from others by its extremely harsh environment which has a extremely frigid and dry climate, very high altitude, little rainfall, a lot of water bodies which are brackish or saline etc.; (3) The others are intermediate, despite their different range of natural conditions, the variance does not cause significant differences except that Western Hubei differs from Southern Xizang.
4. The relationship of ‘species-abundance’ appears to be logarithmic except in Northern Xizang, as expressed by S = αb ^r/r. By analyses, it may be postulated that the species diversity (α-value) possibly relates to the complexity and diversity of environment, principally to microhabitats and microclimates, but not closely to natural macro-conditions.
5. The seven regions show a progressive geographical change from east to west. The qualitative and quantitative distributions of the euglenoids likewise change from east to west, in accordance with the change in location and natural conditions (mainly temperature, altitude and rainfall etc.) of the regions.