Figure 4.

Changes in environmental and biotic characteristics induced by increasing little auk impact (using δ¹⁵N of benthic algae as a proxy of impact). Sampling sites in catchments with little auk colonies are marked with black dots and sites in control areas with open circles. (a) Decrease in pH with increasing bird influence. (b) Increase in total nitrogen concentrations with increasing bird influence. (c) Increase in total phosphorus concentrations with increasing bird influence. (d) Increase in phytoplankton biomass in lentic systems with increasing bird influence. (e) Increase in stream benthic algal biomass with increasing bird influence. (f) Decrease in consumer taxa richness with increasing bird influence. Model details are shown in each panel figure.