Effects of urbanization on small-mammal communities and the population structure of synurbic species: an example of a medium-sized city

Abstract

Theories concerning the impact of urbanization on ground-dwelling mammals are mainly based on large-city studies. We investigated whether the negative effects of urbanization are evident in smaller urban areas, where green areas are usually less isolated from their natural surroundings. Livetrapping of small mammals (Rodentia and Soricomorpha) was conducted between 2007 and 2010 in 15 patches within the city of Lublin (Poland) (147.5 km2, population 354 000) and 15 patches in its agricultural surroundings. A decline in species richness and diversity along an urbanization gradient and an increase in the abundance of species best adapted to the city environment (synurbic species) were observed. The main factors influencing ground-dwelling mammals was isolation of green patches, while the management type of green areas had no significant effect. The genus Apodemus Kaup, 1829, particularly the striped field mouse (Apodemus agrarius (Pallas, 1771)), was the most urban biased. Within the city, A. agrarius alters its habitat preferences and life-history parameters (body mass, seasonal fluctuations, winter survival). Understanding the factors influencing ground-dwelling mammals in medium-sized cities will enable measures to be implemented that could reduce the negative effects of urbanization during urban expansion.