thesis - Theses

Cerna K. et al.
Lepidoptera in Sudetes Mts.: effect of area and isolation
The values for b = 0.3 and c = 0.2 were arbitrarily placed and represent values
characteristic for Lepidoptera (Hanski et al., 2000). It was not feasible to conduct a field
research and find accurate values for all diagnostic species with the capture-recapture
method.
2.4 Relative importance of area, distance and connectivity on species richness
Finally, we have compared the importance of all tested factors, i.e., connectivity (Si), area
(A) and distance to the nearest site (d), using the “zero isocline” model. This analysis
incorporates connectivity values from the incidence function model and shows the
relationship between connectivity and area (S i ~ A) and between connectivity and
distance (S i ~ d). In the first calculation, we fixed distance to its median to avoid the
effect of distance and in the second calculation we fixed area to avoid the effect of area.
Significance of area, distance and connectivity (A, d, Si) was tested by the General Linear
Model (GLM) with Poisson distribution and proved by AIC comparison between a full
model and a model without one of the explanatory variables.
3. Results
3.1 Cluster analyses
Twenty diagnostic lepidopteran species and 10 alpine islands (Tab. 2) were included to
the similarity interpretation and two dendrograms were conducted (Fig. 2 and 3). These
cluster analyses clearly indicate the largest differences in species distribution specific for
individual alpine sites in the High Sudetes Mts.
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