Site selection of European ground squirrels (Spermophilus citellus) in Eastern Romania and how they are influenced by climate, relief, and vegetation

Abstract

Climatic and relief factors could limit the distribution of nonmigratory animals, and especially those that inhabit temperate areas. The limitations are stronger for habitat specialist species and a good understanding of these influences can contribute significantly to the development of conservation measures to protect them. The European ground squirrel (Spermophilus citellus) is a small mammal inhabiting pastures and areas of short herbaceous vegetation from Central and Southeastern Europe with limited data about their colony site selectivity. During the first wide survey of the European ground squirrel in Eastern Romania we identified a strong influence of annual precipitation, aspect, slope, vegetation height, and tree/bush coverage on the species' distribution and density. Lower precipitation values were associated with higher densities of European ground squirrel as well as slope. The same relationship was found with vegetation height and the amount of tree and bush coverage. The European ground squirrel uses areas with a southern and eastern aspect and slopes with a higher gradient. The elevation and the summer-winter temperatures do not have a significant influence on European ground squirrel colonies. Our results will contribute to the species' conservation across its distribution range and will help to determine the most appropriate sites for future relocation and repopulation programs.

Long term (1985–2018) changes of the habitat suitability of European souslik assessed by Maxent modelling based on Landsat satellite imagery – a case study from a mountain landscape of Central Bulgaria

“…Higher temperatures in the second stage are probably associated with more pronounced summer droughts, which affect the condition of the grass cover, recorded by higher reflectance values in the Band 5 range. This interpretation is in accordance with data presented by Koshev and Kocheva (2007) and Zaharia et al (2016), which show that the warming and the accompanying drought during summer have a positive effect, as they cause degradation of the grass cover, thus bringing it closer to the optimal for the species.…”

Maksimum Entropi Modelleme Kullanarak Avrupa Yer Sincabı'nın İki Soyhattı Arasındaki İklim Tercihinin Tahmini

“…Until recently the European ground squirrel occurred in very large numbers in steppe and pasture areas with discontinuous shrubs and trees up to 2,500 m above sea level (Kryštufek & Vohralík, 2005ꓼ Popova et al, 2019. The population size of the European ground squirrel decreased rapidly due to high death rates caused by habitat fragmentation and anthropogenic effects such as agricultural and industrial activities (Zaharia et al, 2016). Today, the population has become fragmented, and even disappeared from peripheral parts of its previous range, as in Germany, Poland and Croatia (Coroiu et al, 2008).…”

Habitat selection in a fluctuating ground squirrel population: Density‐dependence and fitness consequences

“…Dry meadow offers an open landscape and also contains an abundance of dandelions, a preferred food resource for GMGS in our study area (Carleton, 1966 ). Other species of ground‐dwelling squirrels also prefer open areas that provide good visibility, likely to facilitate early detection of predators (Blumstein et al, 2006 ; Ordeñana et al, 2012 ; Zaharia et al, 2016 ); the juxtaposition of these two conditions—food availability and predator detectability—seems to influence habitat selection decisions (Armitage, 2014 ; Hannon et al, 2006 ; McGrann et al, 2014 ). At our study site, GMGS coexist with chipmunks ( Tamias minimus ) and yellow‐bellied marmots ( Marmota flaviventer ); all three species are readily visible, and we have detected no competition for space.…”