论文部分内容阅读
1985—1987年,浙北龙山林场松、栎混交林大山雀繁殖种群的年平均密度为每公顷0.85对,明显高于纯马尾松林的0.57对(t=3.50,P<0.05)。1987年招引区的平均密度为每公顷1.48对,分别比同期混交林和纯林内的密度高2.6倍和3.4倍。通过分析大山雀的繁殖生物学,雏鸟食物中松毛虫比率并结合松毛虫种群密度变化,估计在松毛虫种群密度高的年份,大山雀对越冬后松毛虫幼虫的捕食作用约为0.29％,而在松毛虫种群密度低的年份,捕食作用则增加11.24倍,招引区内捕食作用增加29.19倍。
From 1985 to 1987, the average annual population density of Larix chinensis and Pinus taiwanensis mixed forest was 0.85 pairs per hectare, which was significantly higher than that of pure Pinus massoniana forest (0.57 pairs) (t = 3.50, P <0.05). The average density of attracting areas in 1987 was 1.48 pairs per hectare, which were 2.6 times and 3.4 times higher than the density in mixed forest and pure forest in the same period respectively. By analyzing the reproductive biology of big tits, the ratio of dendrollers in chicks and the densities of dendrolimus population, it is estimated that the predation effect of Great Tit on Dendrolimus punctatus larvae during overwintering is about 0.29% in years with high population densities In the years with low population density of Dendrolimus punctatus, the predation effect increased by 11.24 times and the predation in the lead area increased by 29.19 times.