engleski

Overview of the bird community historical data: bird assemblage multivariate analysis of data collected from five mountain areas in the northern Croatia

Authors compared bird communities from five mountains in the northern Croatia (Risnjak, Papuk, Medvednica, Ivanščica and Cesargrad mountain) using multivariate explorative techniques of qualitative and quantitative historical data. Similarity matrices were prepared based on Bray- Courtis similarity between samples. Non metric multidimensional scaling (NMDS) and complete linkage clustering on qualitative and quantitative similarity matrix respectively was made. Principal component analysis (PCA) on quantitative data revealed bird species that contributed the most to the variability of samples. First three dimensions explained 75.2% of variance in samples (53.1%, 13.5% and 8.6% respectively) withe greatest loadings abundant species like Sylvia atricapilla, Erithacus rubecula, Turdus merula and Phylloscopus collybita. Non-metric multidimensional scaling revealed clear pattern in significant similarity between communities at low altitudes and at the same time – insignificant similarity between assemblages at different heights above sea level with exception from the rule for the community from Papuk at 600 m.a.s.l. The clustering based on similarity matrix on qualitative data made clear separation between communities from different mountains. Authors conclude that monitoring of bird communities on Croatian mountains must be designed as repeated sampling of quantitative data through time.

bird community ; monitoring ; statistics ; non-metric multidimensional scaling ; principal component analysis

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