What does the x and y axis represents in the nmds bray-curtis dissimilarity index?(Vegan package R)

Question

This graph shows the distribution of weeds on 3 treatments ( indicated by color). By googling I found that the graph is bounded between 0 and 1, where 0 means the sites (Treatment) have the same composition (that is they share all the species), and 1 means the sites do not share any species.

But what does x and y axis represents? Why does it require two dimensions?

Thanks

Answer 1

Check out this link.

NMDS ordination randomly places your data in 2D space, but then iteratively improves their ordinational distancing (spacing) to more closely represent their distance in the dissimilarity index. The axis are essentially arbitrary, but display your data in a way which best represents their dissimilarity. Points on the graph that are closer together are more similar (less dissimilar).