Research on the influence of red deer (Cervus elaphus L.) grazing on grassland production in the south-eastern part of Slovenia.

Almost 60% of Slovenian territory is covered by forests and only Finland and Sweden are known as the more forest abundant countries in Europe. Among game that intensifies difficulties in the field of agricultural production, especially in north-eastern and south-eastern parts of the country, roe deer (Capreolus capreolus L.), wild boar (Sus scrofa L.) and red deer (Cervus elaphus L.) prevail. Negative impact of game on agricultural production in the above mentioned parts of Slovenia has risen significantly in the last decade. The data about the population density of game in Slovenia is often based on the payments of their damage on the cultivated plants that are usually performed by the hunting societies. Grassland represents around 60% of agricultural land in Slovenia, and herbage is a very important component of the red deer diet. At the forest border where ruminant ungulate animals spend most of their life, the grassland production for a farmer is often decreased because of the grazing of this hoofed animal. Hitherto, decrease of grassland productiveness from a farmer's perspective, caused by the red deer grazing, was not yet researched in Slovenia. Similar studies were also very rare in other European countries. With the intention of gathering data and learn more about the potential harmfulness of the red deer on grassland production the experiment was performed in the south-eastern part of Slovenia in the year 2002. The influence of red deer grazing on grassland production for forage conservation at the forest border during the vegetation period was studied on three locations (Mala gora, Cvislerji and Mackovec) in the Kocevje region. The experiment lasted from the third decade of March until the first decade of October. Portable cages of size 1x0.5x0.5 m were used to exclude red deer from grazing the herbage. At four sampling dates in the season herbage air dry matter (DM) yield was measured at three different observations (cage-protected plot, cage-protected plot only two to three weeks before sampling date, otherwise freely grazed--removed and unprotected plot). The results from the experiment showed us that red deer grazed on grassland through all seasons and that the regeneration capability of sward was the highest in summer, middle in spring and smallest in autumn. On unprotected plots an average 50% reduction of herbage DM yield was found with the most distant sites also up to 80% reduction.