The results extend those of autonomous systems to case for no autonomous systems . 4 . the stability and the existence of periodic solutions for ecological systems of reaction - diffusion type are discussed by using of smoller invariant domains principle liapunov functional method comparison principle and fixed point theorem 四、研究了用偏微分? ?积分方程描述的生态系统平衡位置的稳定性、渐近稳定性及周期解的存在性、稳定性，采用smoller不变区域原理、比较原理，不动点原理及liapunov泛函方法。
