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Abstract: The spotted wing drosophila (Drosophila suzukii (Matsumura)) is a highly invasive species and attacking different species of berry carrying hosts. Much research has already been done on the crop hosts over the world and in Slovenia, but for wild hosts less is known. On basis of literature and fieldwork we prepared a list of potential and actual known species of wild hosts for Slovenia. In 2019, berries of different species were collected and D. suzukii was either reared from these berries or berries were dissected. In total we found in the literature for Europe 99 species which were used as host for D. suzukii. For Slovenia we found 71 potential hosts and 14 hosts which were actually infested. in Slovenia there was a broad range of potential hosts from 41 genera. The genera with the most potential hosts were Prunus, Lonicera and Vaccinium. Among the potential hosts were also many species which were invasive alien or alien species. The list was discussed in the context of management implications and further research on D. suzukii in Slovenia.
Keywords: spotted wing drosophila, berries, potential hosts, wild hosts, forests, pest control, Slovenia
Published in DiRROS: 11.12.2020; Views: 1197; Downloads: 531
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Abstract: We analyzed variation in the functional composition and diversity of understory plant communities across different forest vegetation types in Slovenia. The study area comprises 10 representative forest sites covering broad gradients of environmental conditions (altitude, geology, light availability, soil type and reaction, nutrient availability, soil moisture), stand structural features and community attributes. The mean and variation of the trait values were quantified by community-weighted means and functional dispersion for four key plant functional traits: plant height, seed mass, specific leaf area and leaf dry matter content. At each study site, forest vegetation was surveyed at two different spatial scales (4 and 100 m2 ) in order to infer scale-dependent assembly rules. Patterns of community assembly were tested with a null model approach. We found that both trait means and diversity values responded to conspicuous gradients in environmental conditions and species composition across the studied forests. Our results mainly support the idea of abiotic filtering: more stressful environmental conditions (e.g., high altitude, low soil pH and low nutrient content) were occupied by communities of low functional diversity (trait convergence), which suggests a selective effect for species with traits adapted to such harsh conditions. However, trait convergence was also detected in some more resource-rich forest sites (e.g., low altitude, high soil productivity), most likely due to the presence of competitive understory species with high abundance domination. This could, at least to some extent, indicate the filtering effect of competitive interactions. Overall, we observed weak and inconsistent patterns regarding the impact of spatial scale, suggesting that similar assembly mechanisms are operating at both investigated spatial scales. Our findings contribute to the baseline understanding of the role of both abiotic and biotic constraints in forest community assembly, as evidenced by the non-random patterns in the functional structure of distinct temperate forest understories.
Keywords: functional composition, functional diversity, ecological gradients, abiotic filtering, trait convergence, trait divergence, spatial scale, forest ground-layer vegetation, Slovenia
Published in DiRROS: 26.05.2020; Views: 1906; Downloads: 1269
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Abstract: Forest damages caused by red deer and some other large herbivore species occasionally feeding on tree bark, are a grave ecological and economic problem in many parts of the world. Winter supplemental feeding is commonly used to mitigate the problem, but its effects are poorly known. This study, carried out at Pohorje (Slovenia) and including over 2,300 trees, used binary logistic regression to analyse the effects of supplemental feeding and many other factors on the probability of bark stripping on spruce. The probability of bark stripping depends on distance from the forest edge, density, age and tree species diversity of stands, slope and aspect of terrain, and red deer density; contrary to expectations, it is not related to distance from feeding places. As much as 35% of spruce trees were damaged. The damage was the highest in younger, denser pure spruce stands, whose favourable protective and microclimatic conditions (thinner snow cover, higher effective temperatures) make them a preferred winter habitat for red deer. They contain,however, little other food but bark. To prevent / diminish bark stripping we propose a stronger thinning of such stands. Supplemental feeding may reduce damage only in exceptional cases, when animals are lured and concentrated in less sensitive areas, but in general we advise against the use of this measure due to its other negative effects.
Keywords: red deer, Cervus elaphus, bark stripping, Norway spruce, Picea abies, forest damages, supplemental feeding, Slovenia, environmental factors
Published in DiRROS: 12.07.2017; Views: 4337; Downloads: 1948
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Abstract: Z raziskavo smo poskusili ovrednotiti morfološke raznolikosti puhastega hrasta(Quercus pubescens Willd.) v Sloveniji. Raznolikost je posledica pestrosti rastišč in možnosti križanja z drugimi vrstami hrastov. Rezultati analize so bili dobljeni na osnovi meritev in opazovanja listov, plodov in kratkih poganjkov puhastegarasta, vzorčenih v osmih populacijah po Sloveniji. Na posamezni lokaciji je bilo izbranih do pet dreves in na posameznem drevesu nabranih do sto listov s kratkih poganjkov v osvetljenem delu krošnje. Na osebkih s plodovi so bili nabrani tudi plodovi. V laboratoriju je bilo na listih izmerjenih, ocenjenih in izračunanih 13 parametrov, na plodovih in kratkih poganjkih pa po en parameter. Uporabljene so bile deskriptivne, univariatne in multivariatne statistične metode za izvrednotenje rezultatov. Analize morfoloških parametrov so pokazale značilne razlike tako med posameznimi osebki v populacijah kot med populacijami. Ugotovljeno je bilo tudi, da vrsto Q. virgiliana (Ten.) Ten. lahko obravnavamo znotraj vrste Q. pubescens.
Keywords: puhasti hrast, Quercus pubescens Willd., Quercus virgiliana (Ten.), morfologija, listi, plodovi, Slovenija, oak, morphology, leaf, fruit, Slovenia
Published in DiRROS: 12.07.2017; Views: 4951; Downloads: 2023
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Abstract: We analysed the characteristics of silver fir (Abies alba Mill.) occurrence and distribution in Slovenia using databases of the Slovenian Forest Service (SFS). Silver fir is the third most widely distributed tree species in Slovenia, occurring in approximately 40 % of total forest area, but abundantly in less than 10 %. Its share in total growing stock varies between separate forest management regions. It is more abundant in the Dinaric and part of the Pre-alpine phytogeographic regions. The highest share in total growing stock reaches at altitudes between 800 m and 1000 m above sea level, forests with silver fir cover the most extensive surface in the altitude belt from 1000 to 1200 m. Silver fir occurs abundantly in 11 syntaxes. Between them, silver fir-beech forests (Abieti-Fagetum dinaricum TREG. 57, syn.: Omphalodo-Fagetum (TREG.57 corr. PUNC.80) MAR et al. 93) strongly prevail, followed by fir forests with fern (Dryopterido-Abietetum KOŠ.65, syn.: Galio rotundifolii-Abietetum BARTSCH.40). Silver fir diameter distribution considerably varies between separate forest management regions. The regions with the highest share of silver fir (Postojna, Kočevje) dominate also in having large diameter silver fir trees, whereas in other regions (e.g. Nazarje, Kranj, Maribor) small diameter silver fir trees are prevalent. Ddevelopmental stage structure shows that in forest stands with silver fir there is a higher share of timber phase, stands in regeneration, youth stands and selective forests. Considering regeneration we can conclude, that more intensive decreasing trend in silver fir share is expected in the Ddinaric phytogeographic region than in northern parts of Slovenia. Successful regeneration due to lower red deer population and balanced stem diameter structure with higher proportion of small diameter trees promise easier conservation of silver fir in northern parts.
Keywords: forest stand structure, forest vegetation, altitude, Slovenia
Published in DiRROS: 12.07.2017; Views: 4371; Downloads: 1744
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