Hypothesis 3: Milder winters and higher water temperature in May
lead to higher functional richness (phenological shift).
The hypothesis that milder winters bring higher functional diversity in
May was based on two assumptions or observations: 1) phenological shifts
occur with milder winters and the summer-like communities will appear
earlier and 2) during the summer the communities are usually
functionally more diverse (Richardson 2008). To test H3, functional
richness was correlated with winter air temperature and water
temperature in May.