将cca图形象化——错误的箭头长度。

I am trying to customize a CCA plot performed in Vegan R package. I have used a benthic cover matrix (%) vs a fish abundance matrix (number of individuals) to run this analysis. I have collected data in 4 coral reefs in 2 years. I want to have the sites dots in different colors (for reef sites) and shapes (years), fish species as text and the benthos as arrows. I have almost done it manually in ggplot, however the arrows length appear to be wrong. Comparing my plot with the "autoplot" and "plot.cca" generated plots, my arrows looks too short. My question is how can I solve this issue?I am trying to customize a CCA plot performed i