Population of small rodents at Forest Administrations Zagreb and Sisak

Sitni glodavci nezaobilazna su biotička komponenta nizinskih šumskih ekosustava kontinentalne Hrvatske koji periodično značajno otežavaju prirodnu obnovu; osobito hrastovih i jasenovih sastojina. U okviru predloženoga rada utvrditi će se struktura i sastav populacija sitnih glodavaca na području Uprava šuma podružnica Zagreb i Sisak (jesen 2021.g) te mogućnosti prevencija šteta od istih. Relativna brojnost te struktura populacija sitnih glodavaca na odabranim lokalitetima utvrđena je metodom lovne linije (transekta) primjenom mrtvolovki te uz primjenu kikiriki maslaca kao mamca. Lovna mjesta su označavana markirnim bambusovim štapovima. Vizualna determinacija ulovljenih jedinki izvršena je pomoću stručne literature utemeljene na morfološkim obilježjima sitnih glodavaca, do razine podporodice ili vrste. Na području uprave šuma podružnica (UŠP) Zagreb unutar istraživanih lokaliteta utvrđena je ukupna relativna brojnost (RB%) od 18%, dok je na području UŠP Sisak iznosila 26%. Uzorkovanjem su ustanovljene slijedeće vrste sitnih glodavaca iz podporodica Murinae i Arvicolinae: Apodemus flavicollis; Apodemus agrarius; Apodemus sylvaticus; Clethrionomys glareolus te jedna jedinka iz podporodice Arvicolinae koju nije bilo moguće determinirati do razine vrste. Sustavno praćenje brojnosti sitnih glodavaca od iznimne je važnosti zbog prevencije nastanka značajnih šteta u sastojinama ekološki i gospodarski važnih drvenastih vrsta: hrasta lužnjaka (Quercus robur L.) i poljskog jasena (Fraxinus angustifolia Vahl.). Rezultati istraživanja, osobito kroz aspekt utvrđene brojnosti, strukture i zastupljenosti vrsta glodavaca, pomažu boljem razumijevanju aktivnosti, dinamike, potencijalnih ugroza, odnosno planiranja mjera zaštite od nepovoljnih utjecaja sitnih glodavaca u kritično ugroženim nizinskim šumskim sastojinama.Small rodents are an indispensable biotic component of the lowland forest ecosystems of continental Croatia, which periodically significantly complicate natural restoration; especially oak and ash stands. Within the framework of the proposed work, the structure and composition of small rodent populations in the area of the Zagreb and Sisak branches of the Forest Administration will be determined (autumn 2021) and the possibilities of preventing damage from them. The relative abundance and population structure of small rodents in selected localities was determined by the hunting line (transect) method using dead traps and using peanut butter as bait. Hunting microlocations/spots within transect were marked with bamboo sticks. Visual determination of caught individuals was carried out using professional literature based on the morphological characteristics of small rodents, up to the level of subfamily or species. In the area of the Branch Forest Administration (UŠP) Zagreb within the investigated localities, the total relative abundance (RB%) was determined to be 18%, while in the area of UŠP Sisak it was 26%. Sampling revealed the following species of small rodents from the Murinae and Arvicolinae subfamilies: Apodemus flavicollis; Apodemus agrarius; Apodemus sylvaticus; Clethrionomys glareolus and one individual from the Arvicolinae subfamily that could not be determined to the species level. Systematic monitoring of the number of small rodents is extremely important because of the prevention of significant damage in the stands of ecologically and economically important tree species: pedunculate oak (Quercus robur L.) and narrow-field ash (Fraxinus angustifolia Vahl.). The results of this research, especially through the aspect of determined number, structure and representation of rodent species, help to better understand the activities, dynamics, potential threats, i.e. the planning of protection measures against the adverse effects of small rodents in critically endangered lowland forest stands