Figure 3. Normalized diatom species abundance for all species (A) and mean Fisher Information (B) for Foy Lake.

Prior to ∼4.5 ka the system had episodic fluctuations in species composition and mean FI, but the overall mean of the FI is unchanging; this suggests that this period was a stable regime characterized by high variability. At ∼4.5 ka species evenness decreases, and the system begins a ∼2 kyr gradual decrease in mean FI. Decreases in FI suggest the system is becoming unstable; as instability increases resilience decreases, warning of a possible regime shift. The system was in this unstable transitional period until ∼2 ka, but it did not attain a new stable-state until ∼1.3 ka.