Interspecific variation in soil compaction sensitivity among forest floor species

Abstract

The present study aimed at exploring the response of herbaceous plant species to soil compaction in forest soils. The research was conducted in central Belgium, in a 4383 ha beech forest. Of the 107 taxa studied, the cover of 65 species (61%) was significantly related to soil compaction. Twenty four forest species (58% of all forest species tested) showed significant growth responses to soil compaction. A few, such as Carex strigosa, Epilobium montanum and Mycelis muralis, showed monotonic reduction in growth with increasing compaction, but about half showed a bell-like response with maximum growth at 200 N ( Hyacinthoides non-scripta) or 400 N (e.g., Carex pilulifera, Melica uniflora) or even 600 N ( Oreopteris limbosperma). Only four species ( Carex remota, C. sylvatica, Rumex sanguineus, Veronica montana) showed positive growth responses with increasing compaction, up to 1200 N. This contrasts with non-forest species where 18 out of 41 showed high tolerance to heavily compacted soils (e.g., Geum urbanum, Glechoma hederacea, Impatiens parviflora, Polygonum hydropiper, Veronica serpyllifolia). The sensitivity of forest species has obvious implications for both conservation and management. The practical measures for long-term conservation of forest herbs are discussed.