光润金线蛭种群数量动态与水体化学因子关系的研究

1994－1998年，在广州市郊菜田水沟每月观察淡水码磺光润金线蛭种群数量。测定水体10个化学因素，用逐步回归分析方法研究光润金线蛭种群数量和化学因素关系。结果表明，每年种群数量动态不同，每年种群数量最多是4－6月份，占全年种群数量的57．14％－71．18％，影响每年种群数量变化的主要化学因素为pH,PO4^3-，Na^ ,Ca^2 ,Mg^2 ，影响5年种群动态的主要化学因素为Fe^3 。

Relationship between population dynamic of freshwater leech Whitmania laevis and chemical factors of water

The population size of freshwater leech Whitmania laevis had been observed every month in Guangzhou kaleyard slot from 1994 to 1998, and ten chemical factors of water were measured. The relationship between the population dynamic of W. laevis and chemical factors was studied by stepwise regression analysis method. The results showed that the population size dynamic of W. laevis was different every year. The maximum of population size appeared in April, May, and June, and the total population size of three months was accounted for 57.14-71.18% of whole year. The major chemical factors that effected on the annual population size were different every year, and the factors included pH value, PO(4)3-, Na+, Ca2+, and Mg2+. Fe3+ was the chief chemical factor effecting on population size during the 5 years observation. The behavior of leech W. laevis was also described in this paper.