Local distribution of native and invasive earthworms and effects on a native salamander

Original article

DOI: 10.1007/s10144-017-0578-1

Cite this article as:
Ransom, T.S. Popul Ecol (2017). doi:10.1007/s10144-017-0578-1
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Abstract

North America is home to both native and invasive earthworms acting as ecosystem engineers as they build burrows that can serve as habitat for other species or otherwise alter soil structure, affecting nutrient cycling and other ecosystem processes. Here I determine where and what earthworm species commonly occur in my study area, and compare effects of native and invasive earthworms on the common woodland salamander, Plethodon cinereus, in field surveys and laboratory experiments. The native earthworm Eisenoides carolinensis was the most common earthworm, followed by two invasive species Dendrobaena octaedra and Octolasion tyrtaeum. The presence of O. tyrtaeum was associated with a narrower O-horizon (i.e., organic layer in the soil). Using structural equation modeling to explore direct and indirect pathways of these three most common earthworm species on salamanders, I found O. tyrtaeum occurrence was negatively correlated with nighttime salamander counts, a proxy for total salamander numbers, mediated by negative effects on O-horizon depth and microinvertebrate numbers. In the laboratory, O. tyrtaeum and D. octaedra consumed more leaf litter per gram of earthworm per day than the native E. carolinensis. However, salamanders consumed earthworms and used burrows of all native and invasive species of earthworms similarly. The potential for negative indirect effects of the invasive earthworm O. tyrtaeum on P. cinereus was demonstrated both in the field and laboratory, highlighting that seemingly small differences between native and invasive ecosystem engineers have the potential to significantly alter the effects of these closely related native and invasive organisms.

Keywords

Dendrobaena octaedra Ecosystem engineer Eisenoides carolinensis Indirect effects Octolasion tyrtaeum Plethodon cinereus 

Supplementary material

10144_2017_578_MOESM1_ESM.pdf (230 kb)
Supplementary material 1 (PDF 230 KB)

Copyright information

© The Society of Population Ecology and Springer Japan 2017

Authors and Affiliations

  1. 1.Department of Environmental StudiesSalisbury UniversitySalisburyUSA

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