Effects of Afforestation with Pines on Collembola Diversity in the Limestone hills of Szárhalom (West Hungary)

We investigated the responses of collembolan communities to pine afforestation in an area formerly characterized by a mosaic of autochthonous downy oak woodland and steppe meadows. Study sites were selected in mixed stands of black pine and Scots pine and control samples were taken from downy oak stands and open steppe meadows. A total of 1884 Collembola specimens belonging to 66 species were collected. Three species, namely Protaphorura pannonica (Onychiuridae), Tomocerus mixtus (Tomoceridae) and Isotoma caerulea (Isotomidae) proved to be new to the Hungarian fauna. There are typical Collembola communities which are specific to different habitat types where species of a given composition can only or predominantly be found in that habitat, as well as some basic common species which occur in every habitat. The highest species richness (41) was found in steppe meadows, considerably lower (34) in downy oak forests, reaching the lowest value (25) in pine plantations. Although several forest species present in the oak woodland were completely missing from the pine forests, there was no significant difference between the Collembola diversities of the two forest habitats. The difference became more prominent in collembolan abundance which resulted in less than half of individuals/m2 in pine plantations compared to the soils of downy oak forests, most likely due to the changed soil conditions, especially of humus characteristics, caused by the pine needle litter. Jaccard similarity measure indicated approximately equal similarity (0.24–0.28) for paired comparison, suggesting that a relatively constant 'basic Collembola community' determined by the soil type typical for the area is present; while dissimilarity in communities between sites are partly provided by spatial heterogeneity of open and forest habitats and by the difference of the vegetation type.