Carry the cause-and-effect idea through arrow diagrams and a visual record of the growing seeds.
Flow-arrow chains
Teach changing conditions and human impacts as arrow diagrams: a box for the cause, an arrow, a box for the effect, another arrow, the effect on survival. Students build these for drought, land clearing and an introduced species, using a consistent style (red arrows for harm).
Picture the data
Have students sketch each pot's seedlings each day at the same scale, building a visual growth strip beside the number table. Seeing the two strips side by side makes the effect of the changed variable obvious before any graphing.