Seasonal shift in the diet of the European ground squirrel (Spermophilus citellus) in mowed or grazed dry grasslands
Abstract
Seasonal diet choice of the European ground squirrel (Spermophilus citellus) was investigated in sheep-grazed, cattle-grazed and mowed dry grasslands in Hungary . Data were collected in April and August focusing on the post-hibernation and pre-hibernation period in 2012 and 2013. We examined food availability in terms of local vegetation composition by quadrate method and Jaccard index while food preferences were analysed by microhistological faeces analysis and Jacobs’ selectivity index. In April, plant species were present in low numbers and cover on all grassland types, and ground squirrels fed on dicots and monocots in similar proportions. Main food plants were Festuca, Achillea and Leguminosae species, but only the latter had significantly different proportions in sheep- and cattle-grazed pastures. In August, the food supply was richer, and diet composition varied on a larger scale. The proportions of the consumed species differed not only seasonally but also by grassland management type. Differences between botanical and faecal composition were higher between the sheep-grazed and cattle grazed habitats, while the values of the mowed areas were closer to the cattle-grazed ones. From April to August the proportion of dicots (mainly the Leguminosae) has increased, while the proportion of the monocots has decreased in food consumption. Our results indicate that cattle grazing ensures the best conditions regarding food supply in the whole active season while sheep (over)grazing may result in poor choice for ground squirrels in April.
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