一、种群密度的影响因素决定种群数量变化一般情况下,种群密度增大,种群中个体数量将增加;反之则减少。影响种群密度变化的因素有很多,其中出生率和死亡率,迁入率和迁出率是直接决定种群密度变化的主要因素。在增长型的种群中,性别比例不同其种群密度的增幅是有差异的:雌性多于 First, the population density of the factors that determine the population changes Under normal circumstances, the population density increases, the number of individuals in the population will increase; otherwise decreased. There are many factors affecting the population density change, of which birth rate and mortality, immigration rate and outflow rate are the main factors that directly determine the population density change. In the growing population, there is a difference in the increase in population density for different sex ratios: more females