What does "stable to increasing/decreasing" mean in the picture below? Does it mean "stable or increasing/decreasing" or "steadily increasing/decreasing"?
You have three ranges of population change: decreasing, stable, increasing. If a value is near the boundary between one level and the adjacent one, you could link the two levels with 'to' so that 'stable to increasing' means 'stable, but near the boundary with increasing', that is the high end of the stable range. 'Stable to decreasing' means 'at the low end of the stable range'.