Temporal dynamics of the depth diversity gradients
The DDG measures of the different richness components show different
degrees of invariability (IV ) as measure for stability. TheIV of Gamma richness (mean=7.14, sd=3.69), ofD(α,max) (mean=6.62, sd=4.11), ofR(α,max) (mean=6.36, sd=2.87), ofR(β,max) (mean=5.89, sd=2.06) and ofR(γ,max) (mean=6.52, sd=2.97) were high in
comparison to the IV of D(β,max)(mean=1.56, sd=0.48) and of D(γ,max) (mean=1.78,
sd=0.53).
For all lakes depth-independent gamma richness showed a small but
significant trend (p < 0.1) towards more species
(Supporting information). Analysing all lakes together, the DDG measures
revealed no significant common trend (p > 0.05)
(Supporting information). For individual lakes slopes of significant
linear models of the Dmax andRmax over years showed mostly positive trends
(richness increasing and peaking at shallower depths, see Supporting
information). The D(α, max) shows two significant
positive trends (peak shifting towards water surface – lake Starnberg
and lake Tegernsee) and two significant negative trends (peak shifting
to deeper waters – lakes Großer Alpsee and Woerthsee). TheD(β, max) increases significantly at Lake
Riegsee, while D(γ, max) increases for lakes
Riegsee, Staffelsee Nord and Tegernsee. For total gamma richness, lakes
Chiemsee, Staffelsee Nord, Staffelsee Süd and lake Starnberg show
positive trends (Table 2).