Redundancy Analysis - how to interpret the plot


New Member
I'm reading a paper that uses a redundancy analysis but I don't know how to interpret the figure. It seems like such a basic thing that I should understand, but I'm having a hard time finding anything that answers my questions.

- What do the axes mean?
- What does it mean when arrows point (nearly) straight down?

Further explanation beyond these questions is also highly appreciated.

Thanks in advance!