Applied Soil Ecology 167 (2021) 104035
0929-1393/© 2021 Elsevier B.V. All rights reserved.
Distribution of earthworm communities in agroecosystems with forested
riparian buffer strips: A multiscale study
Ashley Cameron
a
, Gabriel Boilard
a
, Rapha¨ elle Dubois
a
, Robert Bradley
a, *
, Petra Benetkov´ a
b
,
Agnieszka J´ ozefowska
c
, Naresh Thevathasan
d
, Joann Whalen
e
, Miloslav
ˇ
Simek
f
a
Biology Department, University of Sherbrooke, Canada
b
Institute for Environmental Studies, Charles University, Prague, Czech Republic
c
Department of Soil Science and Agrophysics, University of Agriculture in Krakow, Poland
d
School of Environmental Sciences, University of Guelph, Canada
e
Department of Natural Resource Sciences, McGill University, Ste-Anne-de-Bellevue, Canada
f
Biology Centre, Institute of Soil Biology,
ˇ
Cesk´ e Budˇ ejovice, Czech Republic
A R T I C L E INFO
Keywords:
Field surveys
Earthworm life-forms
Spatial scales
Habitat
Redundancy analysis
Conditional regression trees
ABSTRACT
Knowledge is lacking on the factors controlling the structure and spatial distribution of earthworm communities
within agroecosystems. We frst hypothesized that forested riparian buffer strips (FRBS) within agricultural
landscapes would be a refuge for earthworms, as we predicted higher soil moisture and organic matter inputs in
FRBS than in adjacent agricultural felds (treatments = FRBS vs. Field). We further hypothesized that earthworms
would be most abundant where the chemical quality of above- and belowground plant litter is high, or where soil
disturbance is low. We conducted a feld survey to quantify earthworm species abundances in FRBS and adjacent
agricultural felds in two bioregions, namely Eastern Canada and Central Europe. At each of 77 sites, we collected
and identifed earthworms from three plots within FRBS and within adjacent agricultural felds. In each plot, we
identifed the tree species, understory vegetation, soil drainage class, agricultural crop as well as fve soil
physicochemical properties. In each bioregion and treatment, we found proportionately more endogeic than
anecic or epigeic earthworm species. In Eastern Canada, there were proportionately fewer anecic and more
epigeic individuals in FRBS than in felds; in Central Europe there were fewer endogeic and more anecic
earthworms in FRBS than in felds. We found signifcant bioregion × treatment interactions on earthworm
abundance and soil moisture. More specifcally, in Eastern Canada we found higher earthworm abundance and
soil moisture in FRBS, whereas in Central Europe we found higher earthworm abundance in felds and no
treatment effect on soil moisture. In both bioregions, we found higher organic matter in FRBS than in felds. In
Eastern Canada, earthworm abundance in deciduous and mixedwood stands were higher than in coniferous
stands; in Central Europe, earthworm abundance was highest in deciduous stands only. Within FRBS in Eastern
Canada, the abundance of the prominent endogeic species, Apporectodea rosea, was correlated with herbaceous
plants, notably ferns and graminoids. Conditional regression tree analysis revealed positive relationships be-
tween earthworms and soil clay content, pH, moisture and organic matter. Our results suggest that local and
landscape patterns in earthworm diversity can be predicted by soil and vegetation attributes, however the
relative importance of these factors changes across continental scales due to differences in precipitation patterns
and soil moisture availability. Comparing the distributions of earthworms across different scales provides in-
sights into the potential of different species to spread into new habitats with climate change.
1. Introduction
Forested riparian buffer strips (FRBS) are increasingly prevalent in
temperate agroecosystems due to their capacity to absorb nutrients from
agricultural runoff (Fortier et al., 2015). FRBS may also provide habitat
and migration corridors for wildlife (Machtans et al., 1996; Palone and
Todd, 1997), improve the ecological integrity of streams (Angermeier
and Karr, 1984; Bladon et al., 2016) as well as provide woody material to
* Corresponding author.
E-mail address: Robert.Bradley@USherbrooke.ca (R. Bradley).
Contents lists available at ScienceDirect
Applied Soil Ecology
journal homepage: www.elsevier.com/locate/apsoil
https://doi.org/10.1016/j.apsoil.2021.104035
Received 27 July 2020; Received in revised form 8 April 2021; Accepted 9 April 2021