Marisia - Maros Megyei Múzeum Évkönyve 36/1. (2016)
Zoology
Alina LARION, Victoria NISTREANU, Veaceslav SÍTNIC, Vlad POSTOLACHI relatively high depths, high reproductive potential, intense migration activity, varied composition of trophic resources), enabling it to survive in conditions of intensive agriculture [1, 4, 7, 9, 10]. For the mound-building mouse it is very important not only the possibility of building mounds, but also their preservation, which depends primarily on agro-technical measures (harrowing, plowing) applied to these lands. In general, the presence of the species is conditioned by the availability of trophic resources, represented by seeds of crop and spontaneous plants. In the trophic spectrum of mound-building mouse there were identified 53 species of wild and cultivated plants from 14 families [2]. Terms of ripeness, abundance and availability of certain plant species are the main factors that determine their collection as food reserves in mounds. The aim of the work is to emphasize the role of ecotone zone in survival of moundbuilding mouse during the cold period in the conditions of agricultural ecosystems. Materials and methods The studies have been performed during 2010-2015 in autumn-spring period in various types of agrocoenoses (wheat, maize, sunflower, alfalfa), fallow ground, abandoned land and ecotone zone from the central part of R. Moldova. The mounds have been monitored since the early days of construction up to their finishing. In total 179 mounds were investigated and the following parameters were recorded: large diameter, small diameter and height of the mound. The peculiarities of trophic base were highlighted depending on the biotope. The mound-building mouse individuals were caught with live traps placed on and around the mound (20 traps per mound). All captured individuals were weighed, marked, their external aspect, sex, age and reproductive activity have been considered. The ecological analysis of mound-building mouse populations included the following parameters: the density of individuals in various biotopes, its seasonal dynamics, sex ratio, age groups, reproductive intensity. In mound investigations the following parameters were considered: minimum, maximum and mean values of large diameter, of small diameter, of mound height, mean number of individuals per mound, time period of mound preservation. Results and discussions The annual life cycle of the species M. spicilegus comprises two periods: I - spring - summer - the individuals begin to reproduce and pass in simple summer galleries with 1-2 exits and a nest without food reserves where they remain until August-September; II — Autumn — Winter — individuals live in mounds with complicated system of galleries, with a large nest, food reserves and don’t reproduce [1, 4, 8]. In the cold period of the year M. spicilegus lives in mounds with food reserves and are represented by young individuals from the last generations, forming the basis of population and have much higher survival rate in comparison with those born in first generations. An important feature of individuals from wintering generations is the low mortality during autumn - winter. The mound construction begins in mid-July - early September, after the ripening of fodder plants seeds and toward the end of reproductive process. M. spicilegus gather in groups of 6—14 individuals born in late summer and early autumn and represent the main of moundbuilding mouse population (about 80%) and forms the last cohort, the role of which in the population functioning is to provide shelter and trophic resources for the survival in winter conditions [3]. Most individuals that participate in mound construction are juveniles with body weight of 6—8 g, in which body growth has stopped till the end of winter. The high density of population can be observed in autumn period, after finishing mound construction (Fig. 1). 100
