This study examined the effects of burrow digging and habitation by the European badger (Meles meles) and the red fox (Vulpes vulpes) on soil properties and the plant community. The vegetation of control plots located in a similar but undisturbed habitat was compared with that of 18 burrow plots established at badger setts (N = 9) and fox dens (N = 9) in a lowland forest area in Poland. Soil physicochemical properties at different disturbance levels (mounds, intermounds and reference areas) were also investigated. The animals altered nutrient availability in the burrow plots considerably by excavating material from deep soil horizons that were less acidic and higher in K, Ca, Mg and available P but poorer in C and N. The effect was stronger for the badger, probably because it displaced larger amounts of material and disturbed wider areas. The activity of the two carnivores induced similar changes in plant communities. They increased herbaceous species richness and caused a shift in the herbaceous species composition: versus the control plots, the burrow plots contained more fugitive species (short-living plants typical for disturbed environments), among which ruderal forbs, including nutrient-demanding species, dominated. The carnivores also increased the species richness of fleshyfruited shrubs and trees. The primary reason for this was probably not burrowing but endozoochorous seed dispersal. Overall, the results indicate that the badger setts and fox dens differ significantly from the forest matrix in terms of soil and vegetation parameters, and that they contribute to habitat heterogeneity and biological diversity.

The 13 seed-dispersal networks of the study. Variables:• network: study community.• bioclimate: bioclimatic zone of the study communities.• country: country of the study communities.• plant: plant (seed) species.• bird: bird species.• weight: weight (w ij ) of each pairwise (plant-bird) interaction expressing the quantity of seeds of each plant species i dispersed by each bird species j.

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