Figure 3
Structural equation models of causal influences of canopy (open = 0, closed = 1) and temperature (ambient, ambient +1.7°C and ambient +3.4°C) (both exogenous variables) on soil water content and earthworm density (both endogenous variables) in Cloquet in August 2010 (A), April 2012 (B), June 2012 (C) and October 2012 (D) and in Ely in August 2010 (E), April 2012 (F), June 2012 (G) and October 2012 (H).
Numbers on arrows are standardized path coefficients (equivalent to correlation coefficients). Average soil water content levels during earthworm extractions are indicated by different shades of blue. Percentages in boxes indicate the proportion of explained variance in endogenous variables. Width of the arrows indicates the strength of the causal influence: bold arrows indicate significant (P < 0.05) standardized path coefficients, fine arrows indicate non-significant path coefficients (P > 0.05). Solid arrows indicate positive relationships and dashed arrows negative relationships. Circles indicate error terms of endogenous variables.
