Vol 12, No. 4 (2003) - abstracts
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Peh, Z., Miko, S. & Bukovec, D.: The geochemical background in Istrian soils. Nat. Croat., Vol. 12, No. 4., 195-232, 2003, Zagreb.

The geochemical background is postulated for two major groups of soils of the Istrian Peninsula, depending on the type of bedrock, or parent material as one of the main soil-forming factors. An effort is made to combine conceptual fundamentals of non-linear dynamic theory with the principles, methods and practical application of basic statistics in order to elucidate the nature and origin of elemental subpopulations hidden in the original geochemical data of Istrian topsoils. In this sense, the 4s-outlier test and iterative 2s-statistical technique are utilized, by which the outliers and anomalous values are removed from the total data and assigned to the consequences of non-linear system dynamics, which prevents the development of a simple cause-and-effect relationship between geochemical variables. The geochemical background is then defined as the normal range of data of the remaining data set. As confirmed by the study, the carbonate-derived soils have a higher natural or geogenic baseline and are also more strongly loaded with heavy metals and other trace elements, in some places critically. On the other hand, flysch-derived soils, except for higher Ca contents, are actually depleted in many elements and also devoid of outliers. Such behaviour implies “dilution” due to the characteristic nature of the weathering of the underlying parent material and other soil-forming processes controlling their fate. In a general sense, the character of the probability distribution curves among chemical elements in the topsoil (or soils in general) can be used as reliable indicator of their evolutionary trends, that is, their enrichment or depletion, or, as regards the geochemical background, the equilibrium between the two, which in the case studied depends principally upon the contrasting Istrian bedrock lithology.

Key words: geochemical background, topsoil, parent material, geogene influence, human impact, normal distribution, normal range, Istria, Croatia
Logan, A.: Marine fauna of the Mljet National Park (Adriatic Sea, Croatia). 3. Brachiopoda. Nat. Croat., Vol. 12, No. 3., 233-243, 2003, Zagreb.

Six brachiopod species (1 inarticulate and 5 articulates) are identified and briefly described from Mljet National Park. All are known from the Mediterranean Sea and eastern North Atlantic. The number of taxa is lower than that for the Adriatic Sea (11 species) as a whole, suggesting that further discoveries might be expected in Mljet. Megerlia truncata, usually found between 50 - 350 m elsewhere, occurs occasionally in shallow caves at one locality in the Park, supporting the «bathyal island» hypothesis advocated by French investigators in the Mediterranean.

Key words: marine fauna, Brachiopoda, Mljet, Adriatic Sea 
Legac, M. & Hrs-Brenko, M.: Rhomboidella prideauxi (Leach, 1815) (Mollusca, Bivalvia) first occurrence in the eastern Adriatic Sea. Nat. Croat., Vol. 12, No. 3., 245-247, 2003, Zagreb.

Four valves of the bivalve species Rhomboidella prideauxi (Leach, 1815) (Mytilidae) were collected by Mr. F. Velkovrh in the Kornati archipelago. This is the first finding of the species in the eastern Adriatic Sea. Earlier the species was recorded in the Mediterranean Sea and in the eastern Atlantic Ocean.

Key words: Bivalve, Rhomboidella prideauxi, Adriatic Sea

Dolenec, Z.: Significant growth of nesting pairs of the grey heron (Ardea cinerea) in the river of Krapina valley (NW Croatia). Nat. Croat., Vol. 12, No. 3., 249-251, 2003, Zagreb.

We followed the population growth of the species grey heron in the river Krapina valley from 1992 till 2002. This area is the part of the village Mokrice (46°00’N,15°55’E; Hrvatsko Zagorje region). While only 1 pair of grey heron nested in 1992, the number of nestings pairs had gradually risen to 54 in 2002 (Pearson’s correlation coefficient: 0,98; p<0.001; n=11).

Key words: grey heron, nesting pairs, river Krapina valley, NW Croatia 
Veronica peregrina L. and Veronica scardica Griseb. (Scrophulariaceae), new species in Croatian flora. Nat. Croat., Vol. 12, No. 3., 253-258, 2003, Zagreb. 

Veronica peregrina L. originates from America and has been spreading in Europe since 18th century. We found it in August, 2003, on the bank of a Danube oxbow (Dunavac) in Batina, where it grows in the amphibian community of the alliance Nanocyperion.
Veronica scardica Griseb. is a native European species distributed in Eastern and South Eastern Europe. We found it on wet fine gravel on the bank of te Kupa river at Ozalj, downstream from the HE power station.
Specimens of both species have been deposited in the ZA Herbarium.

Key words: Veronica peregrina L., Veronica scardica Griseb., Croatia
Library / Knjiznica  Croatian Natural History Museum / Hrvatski prirodoslovni muzej