Modeliranje habitatov prostoživečih parkljarjev v Sloveniji : doktorska disertacija

Stergar, Matija (author), Jerina, Klemen (mentor)

Klasične habitatne študije temeljijo na nekaterih nepreverjenih domnevah: i) Rabo habitata uporabljajo kot neposreden kazalnik njegove priljubljenosti in s tem predpostavljajo, da so vsi deli habitata za osebke enako dosegljivi. ii) Napovedni modeli habitata napovedujejo prihodnjo prostorsko razporeditev vrst(e) na osnovi trenutnih vrednosti okoljskih dejavnikov in s tem predpostavljajo, da so okoljski dejavniki časovno nespremenljivi. iii) Izhajajoč iz evolucijske teorije raziskave predpostavljajo, da živali prostor uporabljajo na način, ki jim zagotavlja čim večjo vitalnost. V nalogi smo preizkusili hipotezo, da so navedene domneve pogosto neresnične. Z modeliranjem habitatov navadnega jelena, evropske srne in divjega prašiča v Sloveniji smo demonstrirali vplive napačne rabe domnev in podali usmeritve za njihovo odpravo ali omilitev. V ta namen smo: i) izdelali model habitata jelenjadi, pri čemer smo poleg okoljskih dejavnikov kot pojasnjevalno spremenljivko vključili še stroškovno razdaljo (tj. razdaljo, ki upošteva %prepustnost% habitata) od lokacij preteklih naselitev jelenjadi. Ker ima spremenljivka v modelu pomemben vpliv, ugotavljamo, da današnja prostorska razporeditev jelenjadi v Sloveniji ni zgolj odraz priljubljenosti habitata, temveč tudi nedokončanega prostorskega širjenja vrste. ii) Izdelali smo statičen napovedni model habitata divjega prašiča ob upoštevanju današnjih vrednosti temperature in padavin ter tri dinamične modele ob upoštevanju različnih scenarijev sprememb temperature in padavin do leta 2040. Z vključevanjem napovedi mogočih podnebnih sprememb smo pomembno spremenili napovedi prihodnje prostorske razporeditve divjega prašiča; vsi trije dinamični modeli v primerjavi s statičnim modelom napovedujejo večje območje razširjenosti in večje lokalne gostote divjega prašiča. iii) Paroma smo primerjali vplive istih okoljskih dejavnikov na: a) populacijsko gostoto jelenjadi, srnjadi in divjega prašiča in b) na vitalnost osebkov teh vrst. Ugotovili smo, da krmišča in smrekovi drogovnjaki pomembno pozitivno vplivajo na gostoto in hkrati negativno na vitalnost osebkov jelenjadi. To pomeni, da vrsta prostor uporablja neracionalno z vidika optimiziranja vitalnosti, kar je po naših ugotovitvah v največji meri posledica antropogenih sprememb habitata.

• Language: Slovenian
• Keywords: habitat, modeliranje habitata, prostoživeči parkljarji, navadni jelen, srna, divji prašič, Cervus elaphus, Capreolus capreolus, Sus scrofa, prostorska razporeditev, populacijska gostota, vitalnost, disertacije
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [M. Stergar]
• Year: 2017
• Number of pages: XII, 132 str., [12] str. pril.
• PID: 20.500.12556/RUL-99361
• UDC: 630*15:630*14(497.4)(043.3)=163.6
• COBISS.SI-ID: 898167
• Publication date in RUL: 19.01.2018

STERGAR, Matija, 2017, Modeliranje habitatov prostoživečih parkljarjev v Sloveniji : doktorska disertacija [online]. Doctoral dissertation. Ljubljana : M. Stergar. [Accessed 5 June 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=99361

Secondary language

• Language: English
• Title: Habitat modelling of wild ungulates in Slovenia

Abstract

Classical habitat studies typically rely on a suite of unverified assumptions as follows: i) Treating habitat use as a direct indicator of its suitability assumes that all individuals can access the habitat equally. ii) Existing habitat models predict future spatial distribution of species based on static environmental factors, ignoring the dynamic nature of the environment. iii) Based on evolutionary theory, most habitat studies assume that animals use habitat in a manner to maximise their fitness. We hypothesised that the abovementioned assumptions are often incorrect, thus leading to false conclusions. By modelling habitat use of red deer, roe deer and wild boar in Slovenia we demonstrated the consequences of the misuse of these assumptions and provided guidance on how to avoid or mitigate them. The thesis is divided in three parts: i) We modeled red deer habitat using not only typical environmental factors as the explanatory variables, but also the cost distance (i.e. distance, reflecting habitat permeability) from the red deer reintroduction sites. The model predicted this variable as highly significant, showing that present red deer spatial distribution is not only reflected by the habitat suitability, but also by incomplete spatial spread of red deer. ii) We prepared a static predictive habitat model of wild boar, based on current values of temperature and precipitation, and three dynamic models taking into account different scenarios of temperature and precipitation changes by the year 2040. Incorporating climate change scenarios affected model predictions significantly: all three dynamic models predicted larger distribution range as well as increased local densities of wild boar, compared to the static model. iii) We compared the effects of chosen environmental factors on local population densities and individual fitness of red deer, roe deer and wild boar, respectively. In red deer, both supplemental feeding sites and spruce pole stands have significant positive influence on population density and negative influence on individual fitness. This indicates that red deer habitat use is irrational in terms of maximising fitness. According to our findings this is primarily related to habitat saturation, which in turn is tightly connected to anthropogenic land changes.

• Keywords: habitat, habitat modelling, free-ranging ungulates, red deer, roe deer, wild boar, Cervus elaphus, Capreolus capreolus, Sus scrofa, spatial distribution, population density, fitness, dissertations