Litter-dwelling invertebrates in natural and plantation forests in the southern Carpathians, Romania

Abstract

Forest plantations usually have a poorer fauna than native forests of the same region. Exceptions seem to appear in colder areas of Europe with few native forests. The Jiu Gorge National Park (JGNP) is situated in the Southern Romanian Carpathians, where numerous native, especially beech, forests are present. However, in the southern part of JGNP there are plantations with non-native species, like pine or black locust, where previous studies had reported a poor fauna. Based on this information, we supposed that this fauna poverty in plantations will be obvious also in the case of the litter macrofauna. This was verified by analyzing the litter macrofauna from 15 forests in the JGNP (10 natural forests and five forest plantations). We collected 12,950 individuals belonging to 28 invertebrate groups. The highest number of taxa was registered in the sessile oak forest, while the highest individual number and taxa diversity was observed in two beech forests. In the beech and birch reforestation areas the fauna was poorer than in old mature forests of the same tree species. In contrast to native forests, the fauna in plantations was much poorer, especially in the pine plantations. Detritiphagous taxa were the most affected by factors of the plantations. In the plantations, more mobile groups with various trophic regimes prevail. The plantations that are present in the southern areas of JGNP, replaced the original sessile oak forests, compared to which they have a much poorer fauna. Forest plantations from JGNP have low value for biodiversity, compared to the northern European areas where natural forests became very rare and the fauna is recent. JGNP is not in the same situation, having extended native forests, which are present in the area since the glacial periods. Therefore, these forests shelter the native fauna of the region. There are few plantations, present only in the disturbed part of JGNP, but even there they have only a very low importance for biodiversity. The data from JGNP confirms the fact that zones with high biodiversity and native forests should be conserved.

Key words: Carpathians, beech, forest plantations, past, native, invertebrates, leaf litter, forestry.