Figure
3. A) The mean number of neighbouring ponds (+/- SE) around each pond
within an increasing radius (cut-off distance), where grey shading shows
the full range between minimum and maximum values. B-D) Variograms with
the amount of unique variance of taxonomic richness explained by the
number of ponds within a radius against each cut-off distance, grouped
according to dispersal traits.
With increasing radius size around the focal pond, the number of ponds
within the radius increased rapidly until around 550 meters where the
curve saturates, indicating the most dense part of the pond cluster
(Fig. 3 A). Accordingly, the number of ponds above this distance did not
explain a considerable amount of variance in taxonomic richness in any
of the studied groups (Fig. 3 B-D). At the same time, there was
considerable variance in pond numbers within the scales of 150-550 m
(Fig. 3 A), with related spatial signals in the local taxonomic richness
of four groups (prokaryotes, rotifer and crustacean zooplankton,
dipterans Fig. 3 B-D). In both zooplankton groups, the relationship
between pond number and taxonomic richness was strongest within a circle
radius between 200 and 400 metres, while it was 300-700 metres for
dipterans. As the variation explained by the environment did not show a
similar spatial structuring, this suggests that indeed neighbouring pond
densities are the major driver of the observed pattern (Fig. S4).
Metacommunity
structure
In metacommunity structure, the overall pattern was similar to taxonomic
richness with the environment explaining more variance than space in
most organism groups (Fig. 4). The amount of unique variance explained
by the environment varied between 10.1 and 36.4% and it was
statistically significant in all organism groups. The unique effect of
space varied between 0.7 and 15.6%, being the highest in rotifers and
lowest in prokaryotes (Table S5 and S6, Supporting information). It was
statistically significant for prokaryotes (F(3,43)=1.14,
p=0.0475), heterotrophic microeukaryotes (F(5,40)=1.21,
p=0.026), rotifers (F(7,41)=1.95, p<0.001),
crustaceans (F(5,44)=1.70, p=0.004), and dipterans
(F(2,45)=1.96, p=0.004).