DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 9-10/2022 str. 72 <-- 72 --> PDF |
one from the Soko hunting ground. Additionally, we had 14 records in the period from August 15 to November 9, 2019, which were obtained from a 4-year-old female equipped with GPS collar number 607. The straight-line dispersion distance from the acclimatisation enclosure was calculated. The difference between the mean dispersion distances in 2019, 2020 and 2021 was tested using one-way ANOVA and the Fisher’s LSD test (P < 0.05) after log transformation (STATGRAPHICS 16.1). The collected data were mapped and all spatial analyses were performed using ArcGIS 10.3 Package. Incidence and intensity of bark stripping caused by red deer within the acclimatisation enclosure were determined from 18 to 20 September, 2020. The definition of incidence is the percentage of damaged trees in an area, and the intensity is the severity of damage to an individual tree, such as the number or size of bark wounds (Gill, 1992). Trees of high and coppice origin were randomly selected on the entire surface of the forest, so we mostly moved along isohypses. The diameter at breast height was measured (cm) and the position of the tree in the acclimatization enclosure was determined using a Magellan Mobile Mapper 50 4G GPS receiver. The total number of measured trees of high origin (n = 479) was twice smaller than the trees of coppice origin (n = 999). Each individual tree was assessed for all visible bark stripping damage (recent and aged) and was quantified using a five point scale (Mountford, 1997): 0 = no damage (no bark removed); 1 = limited damage (<10% bark removed); 2 = moderate damage (10-50% bark removed); 3 = severe damage (>50% bark removed); and 4 = very severe damage (ring-barked). Utilization intensity (%) was calculated for trees of coppice origin and represents the ratio of debarked stems and all stems in the stump, e.g. some stumps of common hazel (Corylus avellana L.) had 30 stems. The median values for damaged and undamaged common hazel trees were compared by the Kruskal–Wallis test. RESULTS AND DISCUSSION REZULTATI I RASPRAVA Bark stripping occurred mainly on thinner common hazel stems of coppice origin (≤ 9.9 cm), as well as on thinner aspen, European hornbeam and sycamore stems of high origin (Fig. 2). In total, 1478 stems within the acclimatization enclosure were examined and 301 of them were debarked (20%). The mean stem girth of coppice and high trees was 5.1 ± 4.6 and 13.7 ± 12.1 cm, respectively. Bark stripped common hazel stems were not significantly thinner than undamaged common hazel stems (Kruskal–Wallis test: KW = 1.10, P = 0.29). We found that middle-aged and quality trees of the main species were not damaged: beech (Fagus sylvatica), sycamore (Acer pseudoplatanus), sessile oak (Quercus petrae), Scots pine (Pinus sylvestris), Norway spruce (Picea abies) and wild cherry (Prunus avium). These results indicated that, except properly supplemental feeding, an adequate methodology for the selection of acclimatisation enclosure had been applied, whose habitat quality mitigated the consequences of numerous mistakes made during the implementation of the reintroduction program. During the study period, no bark stripping was observed outside the acclimatization enclosure. The highest incidence and intensity of bark stripping damage were found on the edge of the forest near the best meadow, where there are two old wooden huts and a feeding station with maize and hay. Utilization intensity was the highest in the part of the forest that is below the best meadow and feeding site, and above the moist soil where the only water source is located (Fig. 3). Habitat quality at the release site has a high impact on the success of reintroduction, if the number and origin of the inhabited breeding stock are favourable, which includes the degree to which the animals are dispersed from the release |