In general, the survival threshold is determinedby intensity of the white noise, the mean stress measure in organisms, the populationintrinsic growth rate and stress response rate.

Researches on the ecological thresholds of Suaeda salsa to the environmental gradients of water table depth and soil salinity;

Taking the rodent community and major afforestation tree species in artificial forest system as research objects, the concept of ecological threshold of artificial forest community was put forward.

This paper presents a region-growing algorithm based on the initial point selection in windows and adaptive growing threshold, to segment the element area from PCB picture automatically.

The analysis on the present greening of Zhuhai city is made using carbon-oxygen balance,ecology threshold value and the oxygen requirement etc,and some suggestions are put forward to improve the city ecosystem environment quality and the city ecological effect continuously.