Razmnoževalni potencial evropske srne (Capreolus capreolus L.) : pregled najpomembnejših vplivnih dejavnikov

Evropska srna (Capreolus capreolus L.) je v Sloveniji in tudi drugod po Evropi najpomembnejša lovsko-upravljavska vrsta. Učinkovito upravljanje populacije lahko zagotovimo le na podlagi dobrega poznavanja njene ekologije in osnovnih populacijskih parametrov, ki vplivajo na populacijsko dinamiko vrste. Za čim boljše adaptivno upravljanje s srnjadjo, vključno z ustreznim načrtovanjem poseganja v populacije, je poleg kazalnikov, ki se že uporabljajo v kontrolni metodi, zelo želeno tudi poznavanje variabilnosti razmnoževalnega potenciala, tj. stopnje oplojenosti samic, velikosti legel in spolnega razmerja zarodkov. Dejavniki, ki vplivajo na razmnoževalni potencial vrste, so lahko individualni (še zlasti fenotip samic, tj. velikost, telesna masa, fizična kondicija), populacijski (npr. populacijske gostote, demografskastruktura, socialni stres, genetske značilnosti) in okoljski (kakovost habitata, vremenske razmere, medvrstne interakcije itn.). Dejanski razmnoževalni potencial je posledica naštetih vplivnih dejavnikov in delovanj med njimi, zato se med različnimi populacijami in okolji močno razlikuje. V prispevku je predstavljen pregled evropskih raziskav o vplivu različnih dejavnikov na oplojenost in razmnoževalni potencial srnjadi. Z naraščanjem gostote populacije se praviloma zmanjšuje stopnja oplojenosti samic, prav tako pa se zmanjšuje tudi število mladičev na posamezno srno. Na velikost legla vpliva tudi telesna masa, in sicer se z večanjem telesne mase samic število mladičev na posamezno samico zvišuje. Pri raziskavah vpliva telesne mase na spolno razmerje mladičev pa so različni avtorji prišli do nasprotujočih se rezultatov. Vpliv starosti se kaže v velikosti legla, saj raziskave kažejo na to, da imajo primiparne samice praviloma manjša legla kot odrasle, upad rodnosti pa je povezan tudi s staranjem osebkov. Srnjad iz severnih območij (Skandinavija) ima praviloma večjo telesno maso in posledično tudi večja legla kot srnjad iz južnih območij (npr. Italija, Španija), kar kaže tudi na pomen življenjskega prostora pri reprodukciji srnjadi. Pri nas srnjad živi v širokem gradientu okoljskih dejavnikov in je udeležena tudi v specifičnih medvrstnih interakcijah, ki jih dosedanje raziskave, opravljene v tujini, ne vključujejo. Domače raziskave bi bile dobrodošle, poleg tega pa imamo v Sloveniji tudi izjemne podatkovne baze o odstrelu, masah, spolni in starostni strukturi srnjadi, ki zagotavljajo odlične predpogoje za še boljše razumevanje vplivnih dejavnikov na variabilnost prirastka srnjadi v srednjeevropskem prostoru.European roe deer (Capreolus capreolus L.) is the most important game-management species not only in Slovenia but also in other European countries. For effective game management it is crucial to have an understanding of the ecology and population parameters that shape the population dynamics of the species. Knowledge about the variability of its reproductive potential, i.e. the proportion of fertilized females, litter size and fawn sex ratio, apart from the parameters that are already in use, would be very beneficial for methods of control as it could lead to more efficient adaptive game management, including proper planning of culling measures. Factors affecting the reproductive potential of roe deer include individual (particularly maternal phenotype, i.e. body size, body mass, physical condition), population (e.g. population density, demographic structure, social stress, genetics) and environmental characteristics (habitatquality, weather conditions, interspecific interactions, etc.). The final output of reproductive potential is the sum of all influencing factors and several combinations between them and therefore varies among different populations and environments. Higher densities can lower roe deer fertility rates and furthermore number of fawns per doe. Litter size is influenced by doe\u27s body mass, as heavier females have more fawns in a litter. There are some contradictory findings in studies of sex ratio variation in connection to female body mass. Litter size can also be influenced by age of does, as primiparous females have smaller litters than adults, but also decreases with animal senescence. Roe deer populations from northern environments (Scandinavia) have higher body masses and larger litters than those from the south (e.g. Italy, Spain), which shows the importance of environment for roe deer reproduction. However, in Slovenia this issue has been neglected until now. In the following report we present an overview of the recent European research on factors affecting the fertility and reproductive potential of roe deer. Similar research in Slovenia would also be valuable, as roe deer is exposed to various environmental factors in this area. In addition, it is also involved in unique interspecific interactions that have not been studied in recent foreign research. Furthermore, Slovene distinguishing databases provide an outstanding platform for proficient understanding of different effects on roe deer yield in Central Europe

Pan‐European phylogeography of the European roe deer (Capreolus capreolus)

To provide the most comprehensive picture of species phylogeny and phylogeography of European roe deer (Capreolus capreolus), we analyzed mtDNA control region (610 bp) of 1469 samples of roe deer from Central and Eastern Europe and included into the analyses additional 1541 mtDNA sequences from GenBank from other regions of the continent. We detected two mtDNA lineages of the species: European and Siberian (an introgression of C. pygargus mtDNA into C. capreolus). The Siberian lineage was most frequent in the eastern part of the continent and declined toward Central Europe. The European lineage contained three clades (Central, Eastern, and Western) composed of several haplogroups, many of which were separated in space. The Western clade appeared to have a discontinuous range from Portugal to Russia. Most of the haplogroups in the Central and the Eastern clades were under expansion during the Weichselian glacial period before the Last Glacial Maximum (LGM), while the expansion time of the Western clade overlapped with the Eemian interglacial. The high genetic diversity of extant roe deer is the result of their survival during the LGM probably in a large, contiguous range spanning from the Iberian Peninsula to the Caucasus Mts and in two northern refugia.202

Vpliv individualnih, populacijskih in okoljskih dejavnikov na izbrane parametre razmnoževalnega uspeha samic evropske srne (Capreolus capreolus L.)

We studied the effects of various individual (age and body mass) and environmental factors (several factors, determining the habitat quality), and population density on selected parameters of reproductive potential of European roe deer (Capreolus capreolus L.) females. By determining the presence and counting number of corpora lutea in ovaries we determined fertility, potential litter size and potential reproductive output of roe deer females. We analysed 1894 samples (1312 of them were suitable for further statistical analyses) of female roe deer reproductive organs collected in the period 2013–2015 in 85 hunting grounds, covering whole gradient of roe deer abundance in Slovenia. The research was upgraded by the study on effects of body mass, population density and mean July temperature on reproductive success of does at the continental scale. For this, we performed the meta-analysis of data (population means), collected from 29 studies on 61 roe deer populations from 15 different European countries. Furthermore, we also determined the sex ratio of offspring, firstly based on 39 samples of uterus with developed foetuses, and secondly based on the data on 180 does culled together with their fawns in the period 2013–2015. Our results revealed a high reproductive potential of roe deer females in Slovenia: 97.6 % of females (both yearlings and adults) were fertile, potential litter size (when considering only fertile individuals) was 1.85, and potential reproductive output (when considering also non-ovulating females) was 1.80. Body mass was the most important influential factor that had positive effect on reproductive performance. The (positive) effect of body mass was age-related and its effect was more pronounced in yearlings than in adults. We detected a direct effect (after excluding the effects of age and body mass) of the mean annual temperature: with higher temperatures the reproductive ability increased. Population density did not have any influence on reproductive potential of roe deer females in Sloveniahowever, the negative effect was confirmed at the European level where the gradient of population density is much larger. We observed pronounced inter-annual differences in reproductive parameters of yearlings, and also the differences among different regions of Slovenia (both in yearlings and adults). Sex ratio of foetuses was 1:0.9 in favour of males and sex ratio of fawns 1:1.1 in favour of females, but we did not find any clear influence of maternal body mass on the sex ratio of their offspring.Ugotavljali smo vpliv individualnih (starost in telesna masa) in okoljskih dejavnikov (več dejavnikov, ki opredeljujejo kakovost habitata) ter populacijske gostote na izbrane parametre razmnoževalnega uspeha samic evropske srne – srnjadi (Capreolus capreolus L.). Plodnost in potencialno velikost legla smo določali s štetjem rumenih telesc v jajčnikih. Analizirali smo 1894 vzorcev rodil srn (1312 jih je bilo ustreznih za nadaljnje analize), odvzetih v obdobju 2013–2015 v 85-ih loviščih vzdolž celotnega gradienta prisotnosti srnjadi v Sloveniji. Vpliv povprečne telesne mase samic v populaciji, populacijske gostote srnjadi in julijske temperature na razmnoževalno sposobnost srn smo ugotavljali tudi na nivoju celotne Evrope, in sicer z meta-analizo podatkov, zbranih iz 29 raziskav oz. 61 populacij srnjadi iz skupno 15 evropskih držav. Ugotavljali smo tudi vplive na spolno razmerje mladičev, in sicer na podlagi 39 vzorcev z že razvitimi zarodki ter s pomočjo podatkovnih baz, iz katerih smo pridobili podatke o 180-ih srnah, uplenjenih skupaj z dvema mladičema v obdobju 2013–2015. Srne v Sloveniji imajo v splošnem velik razmnoževalni potencial: 97,6 % vseh analiziranih samic (mladic in odraslih srn) je bilo plodnih (so imele ovulacijo v letu, ko so bile odstreljene), povprečna potencialna velikost legla (upoštevaje samo plodne osebke) je bila 1,85, povprečna potencialna razmnoževalna sposobnost (upoštevaje tudi neplodne osebke) pa 1,80. Na razmnoževalno sposobnost srn je imela največji (pozitiven) vpliv telesna masa srnvpliv je tudi starostno pogojen in je večji pri mladih kot starejših srnah. Med okoljskimi dejavniki je imela največji neposredni vpliv (po izločitvi vpliva starosti srn in vpliva telesnih mas) povprečna letna temperatura: z naraščanjem le-te se razmnoževalna sposobnost srn povečuje. Vpliva populacijske gostote srnjadi na nivoju Slovenije nismo zaznali, bil pa je potrjen na nivoju Evrope, kjer je gradient populacijskih gostot precej večji kot v Sloveniji. Ugotovili smo tudi izrazite medletne razlike v razmnoževalnih parametrih mladic in razlike v potencialni velikosti legla mladic ter odraslih srn med posameznimi regijami, ki so posledica različnih klimatskih in habitatnih dejavnikov. Ugotovljeno spolno razmerje zarodkov je bilo 1:0,9 v prid samčkov, spolno razmerje mladičev pa 1:1,10 v prid samičk, izrazitega vpliva telesnih mas mater na spolno razmerje pa nismo ugotovili

Značilnosti rasti izolatov gliv Chalara fraxinea in vpliv različnih gojišč

Raziskovali so hitrost rasti glive Chalara fraxinea v čisti kulturi. Poskus je obsegal 12 različnih glivnih izolatov (6 iz Poljske, 6 iz Slovenije) na 8 vrstah gojišč (sladni agar, sladni agar s streptomicin sulfatom, krompirjev agar, vodni agar, Czapek agar, agar z bukvijo, agar z malim jesenom in agar z velikim jesenom) v 3 ponovitvah. Meritve premerov glivnih kolonij so opravljali 8 tednov. Izračunali so hitrosti rasti izolatov gliv na vseh vrstah gojišč in naredili statistično analizo z enosmerno analizo variance ter Kruskal-Wallisovim testom. Opravili so izolacijo glive iz lesa 3-4-letnih drevesc velikega jesena (Fraxinus excelsior), ki so kazali znake jesenovega ožiga. Rezultati poskusa so pokazali, da obstaja velika variabilnost hitrosti rasti posameznih izolatov in na različnih gojiščih. Zakonitosti hitrosti rasti med izolati na različnih gojiščih niso jasno definirane. Na gojiščih, pripravljenih z lesom izbranih drevesnih vrst, in na krompirjevem agarju je bila rast najhitrejša. Rast glive na gojiščih, pripravljenih iz izvlečkov lesa, ni dober kazalec dovzetnosti drevesne vrste za okužbo z glivo, saj je gliva dobro priraščala na gojišču z bukovim lesom. Slovenski izolati so na večini gojišč rasli hitreje kot poljski, verjetno zato, ker so bili starejši. Relativno počasna rast glive na sladnem agarju je bila primerljiva z navedbami v literaturi.In this study, growth rate of the fungus Chalara fraxinea in pure culture was evaluated. 12 different isolates of the fungus (6 from Poland, 6 from Slovenia) were included to the assay. They were grown on 8 types of growth media (MEA, MEA with streptomycin sulphate, PDA, WA, Czapek agar, agar with beech, agar with flowering ash and agar with common ash extract) in 3 replicates. Colony diameters were measured regularly, within 8 weeks. Colony growth rate was calculated for each culture media and statistic analysis with one-way ANOVA and Kruskal-Wallis test was performed. Fungal isolations from 3-4 year old common ash (Fraxinus excelsior) trees, affected by ash dieback, were made. Results showed variability in growth rate between isolates and on different types of growth media, however, no clear regularities were indicated. Colony growth rate was higher on PDA and on growth media with wood extracts. The fungus growth on growth media with wood extract does not show actual tree species susceptibility to the disease since growth on beech extract medium was high. Growth rate of slovenian isolates was higher on most of the media, probably because of older isolates. The relatively low fungal growth rate on MEA was similar to that described in literature