Kelemen Imola (szerk.): A Csíki Székely Múzeum Évkönyve 8. (Csíkszereda, 2012)

Régészet - Tibor-Tamás Daróczi: Environmental Changes During the Holocene in Transylvania

ENVIRONMENTAL CHANGES DURING THE HOLOCENE IN TRANSYLVANIA

In summary, periods of stability and differentiation can be distinguished in the flora of Transylvania. Based on the Bray-Curtis dissimilarity,77 periods of site similarities are discernible in low and mid altitude areas at the start of the Preboreal (75.3 %), Early Atlantic (77.4 %) and the Late Subatlantic (78.6 %) (Fig. 7-upper). In the same elevation zones, differentiation of species occurred in the Middle Preboreal, Early Boreal, Late Atlantic and Early Subatlantic. In the same sequence, during the Middle Boreal and Early Subatlantic, homogenisation occurred as well, while in the Late Boreal, Middle Subboreal and Middle Subatlantic periods of stability can be recognised (Fig. 7-lower).78

Fig. 7. Site similarity (Bray-Curtis) at c. 250-year intervals; mean pairwise percentage similarity (upper) and change in mean pairwise similarity over time (lower) for low- and medium-elevation sites (after Feurdean ET AL. 2010, fig. 4/a-b)

At high altitude sites, similarities were strengthened in the Early Preboreal (79 %), Late Subboreal and Early/Middle Subatlantic (74.69-83.6%), while major differentiation occurred from the Middle Boreal to Middle Atlantic and Late Subatlantic (Fig. 8-upper). Homogenisation occurred in the Early and Late Preboreal, Middle Atlantic with no distinct period of longer stability (Fig. 8-lower).79

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Fig. 8. Site similarity (Bray-Curtis) at c. 250-year intervals; mean pairwise percentage similarity (upper) and change in mean pairwise similarity over time (lower) for high-elevation sites (after FEURDEAN ET AL. 2010, fig. 4/c-d)

77 A statistic that is used to quantify compositional differences between two sites, based on the ratio of species and species richness. - personal communication of Katalin-Emilia Daróczi and Kinga Fetykó.

78 Feurdean et al. 2010, 2203-2204.

79 Feurdean et al. 2010, 2204-2205.

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