Vijabilnost populacije tekunice (Spermophilus citellus) pod uticajem promene klime i staništa

Abstract

U radu je analiziran odgovor lokalnih populacija tekunice u Vojvodini na promene uslova klime i korišćenja zemljišta. Odgovori populacija tekunice (tipičnog predstavnika otvorenih staništa i idealnog model organizma) na pomenute promene omogućiće razmatranje kako mere na regionalnom nivou: i) mogu unaprediti zaštitu i očuvanje tekunice ii) ublažiti efekti promene klime i korišćenja zemljišta iii) mogu usaglasiti razvoj poljoprivrede sa očuvanjem biodiverziteta travnatih ekosistema. Kako bi se odgovorilo na pitanja i postavljene hipoteze u radu sprovedeno je terensko istraživanje, korišćen standardni prostorni pristup i ekološko modelovanje. Sve primenjene tehnike su komplementarne jedna drugoj u dobijanju odgovora na postavljena pitanja gde rezultati jedne analize predstavljaju ulazne podatke za drugu analizu. U tezi su korišćeni podaci dobijeni na osnovu terenskog mapiranja lokalnih populacija i podaci iz eksperimenta modelovanja kao i serija podataka dobijena cenzusom kolonija tekunica i terenskim uzorkovanjem zemljišta i vegetacije. Rasprostranjenje populacija oblikuju klimatski uslovi ali pored abiotičkih faktora uslovljavaju ih i biotički faktori i kretanje jedinki. Promena klime direktno utiče na distribuciju optimalnih uslova. Istraženo je u kojoj meri će doći do promene u distribuciji optimalnih uslova sredine za tekunicu. Potencijalna promena analizirana je uzimajući u obzir klimatski scenario Max Plank Instituta sa tri rcp projekcije i tri generisana prostorna scenarijadistribucije otvorenih travnatih staništa u Vojvodini. Sagledavanje mogućih efekata promene sredinskih uslova dalo je mogućnost da se ukaže na zone koja će biti ključne za očuvanje populacija tekunica i travnatih ekosistema u Vojvodini. Sledeće, s obzirom da disperzija jedinki, dostupnost resursa kao i delovanje lokalnih faktora ugrožavanja (barijere, menadžment staništa, varijabilnost sredinskih uslova, predatorstvo, poljoprivredne aktivnosti) oblikuju distribuciju populacija u prostoru, u radu je analiziran i uticaj promene ovih faktora na distribuciju populacija. Na području lokalnog slatino-stepskog koridora srednjeg Banata istražene su kompozicija biljnih vrsta, upravljanje na staništu, promena u kompoziciji okolnih poljoprivrednih kultura i dinamika populacije. Dobijene su informacije o efektima lokalnih uslova na prisustvo kolonija, veličinu kolonija i kondiciono stanje jedinki. Informacije dobijene u ovim poglavljima su kasnije korišćeni za formiranju seta kriterijuma radi karakterizacije svih mapiranih staništa u Vojvodini. Dalje, veliku ulogu u poljoprivrednom predelu imaju tranziciona staništa koja povezuju lokalne populacije. Identifikovanje koja tranziciona staništa koriste jedinke tekunice je ključno za očuvanje populacija i ublažavanje trena opadanja brojnosti. Na terenu su mapirani distribucioni obrasci lokalnih kolonija tekunice i istraženo je da li postoje razlike na lokalnom i predeonom nivou u distribuciji nastanjenih i napuštenih staništa na području Vojvodine. U radu je dalje analizirana mapirana mreža staništa lokalnih populacija i pretpostavljano je da populacije funkcionišu i održavaju se u okviru metapopulacione strukture. Sa druge strane, veličina i površina koju zauzimaju potencijalne metapopulacione struktura mapirane mreže staništa koje se razlikuju u odnosu na okupiranost, kapacitet i povezanost nisu bile poznate. Kako bi se kvantifikovale potencijalne metapopulacione jedinice i utvrdila vijabilnost svake definisane pojedinačne metapopulacione mreže korišćen je metod ključnog fragmenta. Mapirane mreže evaluirane su iz perspektive samog taksona i testiran je potencijalni disperzioni kapacitet. Proverena je permeabilnost predeonog matriksa između mapiranih staništa i identifikovani su potencijalni koridori za jedinke. Ovakav pristup daje uvid u koji deo predela je značajno i neophodno ulagati ograničena sredstva za zaštitu prirode unutar regiona Vojvodine. U tezi je na kraju ocenjen doprinos trenutne regionalne konzervacione prakse zaštiti staništa tekunice, dat pregled slabih tačaka i predlog predeono adaptacionih mera koji će doprineti zaštiti i očuvanju populacije tekunice kao i mozaika otvorenih travnatih staništa.

The study analyzes the European ground squirrel (EGS) population response to land use and climate change in Vojvodina. The response of the EGS population (typical species of open grassland habitats and the ideal model organism) to changes in environmental conditions in this region will enable consideration of following measures at the local and landscape level: i) effective protection and conservation of the EGS and habitat it relay on; ii) climate change and land use mitigation and adaptation iii) how can we harmonize the development of agriculture and preserve the biodiversity of grassland ecosystem in agricultural settings. In order to answer the questions of this study, the field research was conducted, standard spatial approach and ecological modeling were employed. All applied techniques are complementary to one another in obtaining responses to the questions asked. The results of one analysis represent the input data for the following one. The data for the study were obtained: from EGS local populations’ field mapping, from the modeling experiment, the census campaigned and the field sampling of soil and vegetation. Distribution of populations, which in addition to abiotic factors are conditioned by biotic factors and movement of individuals were evaluated in the context of climate change. Climate change directly affects the distribution of optimalconditions. The potential changes in distribution of optimal environmental conditions for EGS were assessed by considering changes in abiotic factors and the availability of grasslands. The climate scenario obtained using a dynamic vegetation map with three rcp projections and three spatial scenarios for the distribution of open grasslands were used. The extrapolation of a suitable area obtained by presence only model Maxent gives the possibility to point to the zones that will be crucial for preserving the populations and grassland ecosystems in future. Dispersion of individuals, availability of resources and the operation of local threats (e. g. barriers, habitat management, variability of the central conditions, predation, agricultural activities) shape the distribution of populations in space and time. In the area of the local saline steppe corridor of the central Banat in Vojvodina i) the composition of plant species, ii) open grassland habitat management iii) changes in the composition of surrounding crops and iv) population dynamics of EGS have been investigated. The effects of local conditions on the presence, size of colonies and condition of the individuals of EGS were assessed. The information obtained in these chapters was later used to form a set of criteria for the characterization of all mapped habitats in Vojvodina. In the agricultural area, transitional habitats connect local populations of many species. Identifying transitional habitats which potentially can be used by focal species is key to protect and mitigate population decline. For this purpose distribution patterns of the colonies were mapped in the field. The haracteristics and differences among mapped patches at the local and sub landscape scale were detected and evaluated. Later in the study the network of mapped habitats patches was evaluated. It was assumed that mapped populations in Vojvodina function within several metapopulations networks. However, the size and area of potential meta-population networks are likely to differ in relation to occupancy, capacity and habitat connectivity. The knowledge of potential population units was scarce. In order to quantify the potential population units, to determine the viability and conservation priority of each defined habitat network the key patch approach was used. Mapped networks were evaluated from the perspective of the taxon itself and potential dispersed capacity was tested. The ermeability of the matrix area, connectivity of the mapped habitats and the distribution of potential corridors was verified. This approach gives an opportunity to assess to which part of the area and population it is necessary to invest limited resources for nature protection in Vojvodina.The contribution of current regional conservation practice to protection of EGS was evaluated, a brief overview of the weak points and the proposal of preciseadaptation measures that should be taken in Vojvodina are presented in final chapter. The results of this study propose the development of spatial adaption measures and conservation design that will contribute not only in preserving EGS and habitats it relay on but also other wild plant and animal species in this intensively used agricultural settings.