Fig. 6. Assessment for effects of agricultural land use on fish catches across the 31 study lakes.

Changes or effects were calculated as differences (actual or relative) from the 1970–2014 medians. a shows simulated changes in agricultural land use (LUag), in terms of percent of catchment area (Acat), associated with a 25% decrease in fish catches. b, c show simulated effects of changes in LUag on water level (WL) and chlorophyll a (CHL). d, e depict how simulated effects of WL and CHL, in response to changing LUag, affected fish catches. h summarizes these linkages within a subset of the Bayesian networks model that demonstrates the effects of LUag, where the width of each arrow is a qualitative indicator of the strength of the hypothesized causal effects. In a–e, bars represent simulated median changes and error bars represented first and third quartiles of the simulated changes. Dashed lines divide the lakes into “positive” (top 9 lakes), “mixed” (middle 10 lakes), or “negative” (bottom 12 lakes) associations between LUag and fish catches, based on one-tailed 75% credible intervals, as indicated by error bars in a. For positive lakes, a 25% decrease in fish catches was associated with decreasing LUag. For mixed lakes, a 25% decrease in fish catches was associated with both decreasing and increasing LUag. For negative lakes, a 25% decrease in fish catches was associated with increasing LUag. Source data for a–e are provided as a Source Data file.