If you want to fit nonlinear relationships to data where those relationships can vary by groups (eg species) then we have a paper for you:
Hierarchical Generalized Additive Models https://t.co/v0yc5nTpQS in @thePeerJ #oa #ecology #rstats
w @ericJpedersen @millerdl @noamross https://t.co/OQLDWbaa94