Invasion by Exotic Earthworms Alters Biodiversity and Communities of Litter- and Soil-dwelling Oribatid Mites

Abstract

Exotic earthworms are drivers of biotic communities in invaded North American forest stands. Here we used ecologically important oribatid mite (Arachnida: Acari) communities, as model organisms to study the responses of litter-and soil-dwelling microarthropod communities to exotic earthworm invasion in a northern temperate forest. Litter-and soil-dwelling mites were sampled in 2008-2009 from forest areas: (1) with no earthworms; (2) those with epigeic and endogeic species, including Lumbricus rubellus Hoffmeister; and (3) those with epigeic, endogeic, and anecic earthworms including L. terrestris L. Species richness and diversity of litter-and soil-dwelling (0-2 cm soil depth) oribatid mites was 1-2 times higher in sites without earthworms than in sites with worms. Similarly, litter-dwelling oribatid mites were between 72 and 1,210 times more abundant in earthworm-free sites than in sites with worms. Among earthworm invaded sites, abundance of litter-dwelling oribatid mites in sites without the anecic L. terrestris was twice as high in May and 28 times higher in October, compared to sites with L. terrestris. Species richness, diversity, and abundance of oribatid mites were greater in litter-layers than in the soil-layers that showed a varied response to earthworm invasion. Species compositions of both litter-and soil-dwelling oribatid mite communities of forests with no earthworms were markedly different from those with earthworms. We conclude that exotic earthworm invasions are associated with significant declines of species OPEN ACCESSDiversity 2011, 3 156 diversity, numbers, and compositional shifts in litter-and soil-inhabiting communities. These faunal shifts may contribute to earthworm effects on soil processes and food web dynamics in historically earthworm-free, northern temperate forests.

Side‐swiped: ecological cascades emanating from earthworm invasions

“…Earthworm ecosystem engineering also alters the diversity and composition of soil microbial and faunal communities (Burke et al . ), promoting the proliferation of fast‐growing bacteria (Ferlian et al . ) and large‐bodied fauna (Schlaghamersky et al .…”

“…Earthworm ecosystem engineering also alters the diversity and composition of soil microbial and faunal communities (Burke et al 2011), promoting the proliferation of fast-growing bacteria (Ferlian et al 2018) and large-bodied fauna (Schlaghamersky et al 2014). At the same time, the density and diversity of epigeic (ie surface-litter dwelling) fauna decline due to removal of their habitat .…”

Trophic cascades, invasive species and body-size hierarchies interactively modulate climate change responses of ecotonal temperate–boreal forest

“…As competitively superior species compared with indigenous detritivores, earthworms retain an enormous amount of biomass previously fixed in organic soil layers, indigenous soil micro-organisms and arthropods. Thus, earthworm invasion is likely to lead to simplification of soil food webs [31,35].…”

Consequences of distributional asymmetry in a warming environment: invasion of novel forests by the mountain pine beetle

“…The invasive potential of insect herbivores is often enhanced in new habitats where they encounter both enemy-and defensefree space, resulting from a lack of coevolutionary association with those elements of the invaded habitats (Jeffries andLawton 1984, Gandhi andHerms 2010). As a consequence of missing or ineffective population regulators, invasive arthropods can have devastating consequences on invaded habitats and lead to cascading effects at multiple trophic levels (MacFarlane and Meyer 2005, Poland and McCullough 2005, Hanula et al 2008, Gandhi and Herms 2010, Burke et al 2011, Herms and McCullough 2014.…”