Effect of landscape management on earthworm communities in temperate grasslands

Abstract : Earthworms provide a large number of ecosystem services that rely on the presence and association of specific species (Blouin et al., 2013). A better understanding of the factors ruling earthworm communities’ assembly is therefore essential. These assembly rules of earthworm communities are govern by the filter theory leading to a pool of local species (Lortie et al., 2004). Many studies focused on interactions between agriculture such as land use or management practices and earthworm communities. Landscape has already been shown to influence the distribution of various organisms, however, very few studies took into account the influence of landscape on earthworm communities (Crittenden et al., 2015; Regulska and Kolaczkowska, 2015) and to our knowledge, none were performed on grasslands. A landscape is composed of patches of habitats separated by ecological continuities. These ecological continuities (ditches, hedges, roads...) can be habitat for organisms, or can play the role of corridors or barriers for their dispersal between two environments. Dupont et al. (2015), observed population flows across the landscape leading to population diversification of A. icterica. The aim of this work was to determine the influence of landscape on earthworm communities’ assembly in grasslands by investigating a high spatial scale (250 and 500 m around each grasslands) and a finer one (within each grasslands). For the large scale, we selected 27 grasslands with a gradient of richness and diversity of the elements of landscape as well as of the hedgerow lines up to 500 m around. We sampled earthworms at 30 m from any natural or anthropogenic edge. For the fine scale, we selected 3 grasslands on which we sampled earthworms along a gradient at 1 m, 5 m, 10 m and 30 m from two borders, a hedgerow and a road. On each sampling point, earthworms were sampled with the application of formaldehyde followed by hand sorting on a square meter repeated three times. Each individual collected was identified to the species and weighed. Preliminary results showed that, at the large scale, the diversity of the landscape (richness or Shannon index) had a negative impact on the total richness of earthworm. The amount of hedges was positively correlated to the number of total and epi-anecic species but negatively related to epigeic species. At the fine scale, a specific effect of gradients on earthworm communities was observed for each of the three grasslands. For example, a positive gradient of earthworm abundance and biomass from the edge towards the centre of the grassland was observed in only one of the three grasslands. Some earthworm species such as A. caliginosa or A. chlorotica showed a negative gradient of their individual adult weight from the edge to the centre of the grassland. Overall no edge effect on the richness of earthworms was observed.
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Submitted on : Friday, August 2, 2019 - 5:12:14 PM
Last modification on : Sunday, August 4, 2019 - 1:09:04 AM

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  • HAL Id : hal-02262564, version 1

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Kevin Hoeffner, Cécile Monard, Daniel Cluzeau. Effect of landscape management on earthworm communities in temperate grasslands. 1st International Earthworm Congress, Jun 2018, Shanghaï, France. ⟨hal-02262564⟩

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