Zero net growth isocline

The zero net growth point expanded to the two-dimensional resource space produces a zero net growth isocline (ZNGI) as illustrated in Figure 11.5. At the ZNGI, the rate of reproduction and the mortality rates are equal, resulting in... 

Zero net growth isocline (ZNGI). The ZNGI is the line in the resource space that represents the lowest concentration of resources that can support a species. In an equilibrium situation, the equilibrium will eventually be drawn to a point along the ZNGI. In the shaded area of the resource space, the population will grow. In the whiter area, extinction will eventually occur. 

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