DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 9-10/2011 str. 54 <-- 54 --> PDF |
T. Kirin, J. Kralj, D. Ćiković, Z. Dolenec: HABITAT SELECTIONAND SIMILARITYOF THE FOREST ...Šumarski list br. 9–10, CXXXV (2011), 467-475 Abundance of forest birds is largelydependent on the forest types. Studies which relates habitat characteristics to species abundance often has a goal to find out whether structural or floristic characteristics of vegetation has more impact to species distribution abundance. While MacArthurand MacArthur(1961) and Blondeletal. (1973) consideredthatphysiognomic structure of foresthasmajorimpact on small insectivorous forest birds, Moskát(1988) foundthat floristic structureis the most important factor affecting bird population densities.These studies do not explain why birds occupy particulate habitats, but they identify habitat characteristics which appear regularly in bird territories and which may be correlated with proximate factors in habitat selection (Bertin1977). Bird-habitat correlations are just one segment of the analysis of habitat selection (Sherryand Holmes1985). Although they do not give information about the processes or dynamics of habitat selection, they have a value as a tool in the forest management. Forest bird communities are, unlike many plants and invertebrates, relatively little affected by historical factors (Fuller1990) and changes in forest management practice can quickly affect breeding bird communities. In this study, we compared bird communities and floristic and structural characteristics of forests in two Nature Parks in northwest Croatia. Our aim was to identify the most important habitat characteristics that influence the diversity of songbird communities and density of ecological group of birds in different forest stands.We also test whether higher similarity of physiognomic or floristic structure results with higher similarity of bird communities between two studied areas. Study area covers the territory of two Nature Parks, Medvednica (45°51’N 15°51’E– 46°01’N 16°12’ E) and Žumberak – Samoborsko gorje(45°43’N 15°15’E– 45°47’N 15°41’E) situated in NW Croatia, only 15 km apart (Fig1), on altitudes from 100 to 1178 meters above sea level. Climatic and geological characteristics and vegetation cover of the two mountains are similar. Both mountains are part of Croatian continental karst.Average annual temperature is around 6oC and annual precipitation around 1200 mm with the rain maximum from April to September. Forests cover over 60% of area in both Nature Parks, but they are mostly continuous on Medvednica and more fragmented on Žumberak – Samoborsko gorje. Forests of sessile oak and common hornbeam Epimedio-Carpinetum betu li(Ht. 1938) Borhidi1963 are predominant in the lower mountain area, forests of sessile oak and chestnut Querco petraeae-Castanetum sa tivaeHt. 1938 grow on more acid soils,while forests of pubescent oak METHODS – Metode Study Area –Područje istraživanja Figure 1Position of the study area. Slika 1.Položaj istraživanih područja. and hop hornbeamOstryo-Quercetum pubescentis, (Ht.AbietetumVukelićet Baričević2007, while on 1950) Trinajstić1979cover steeper and warmerŽumberak– Samoborsko gorje fir-beech forests are not slopes.The beech forestsAremonio-Fagion(Horvatpresent (Trinajstić2001) and coniferoustrees (fir 1938) Borhidi in Töröketal. 1989 and Luzulo-Fa-Abies albaMill., sprucePicea abies(L.) Karsten, pine gionLohm et R.Tx. in R.Tx. 1954predominate in thePinus sylvestrisL. and larchLarix deciduaMill.) are higher mountain area.The highest parts of Medvednicaonly cultivated(Jelaskaet al2005, Nikolićand are covered with fir-beech forests Festuco drymeiae-Kovačić2008). |