Linking Specialisation and Stability of Plant ... - OPUS Würzburg

4.5 discussion 77
1.0
A
1.0
B
0.5
0.5
Mutualism specialization
0.0
1.0
0.0 0.5 1.0
C
0.0
1.0
0.0 0.5 1.0
D
0.5
0.5
0.0
0.0
0.0 0.5 1.0
Plant niche overlap
0.0 0.5 1.0
Figure 4.4: Contrasting effects of specialisation of plant-animal mutualistic
interactions on four different measures of ecological stability. In
all graphs, the level of stability is plotted as a function of plant
niche overlap and mutualism specialisation. Darker shades of
grey denote higher stability. Note that a different scale and resolution
were used for Fig. A (same scale and resolution as in
Fig. 1) compared to Figs. B-D (scale and resolution as in Fig. 2).
The four stability measures are: A resilience criterion, B domain
of attraction, C persistence criterion, D ecosystem function criterion.
See Table 4.1 for a comparison of the properties of these
stability criteria.
2x2-species mutualistic systems are possible. A positive effect
of specialisation on system stability mainly results from the reduced
risk of competitive exclusion, a fact that is rarely considered
in the conservation literature. Furthermore, our results
indicate that specialisation has a different effect on stability of
plant-pollinator systems as compared to other plant-animal mutualistic
systems, due to the reproductive disadvantage of rare
plant species in generalised pollination systems.
The four criteria of ecological stability applied in this study
did not produce consistent trends regarding the relationship be-