Local distribution of native and invasive earthworms and effects on a native salamander
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 earthwormEisenoides carolinensiswas the most common earthworm, followed by two invasive speciesDendrobaena octaedraandOctolasion tyrtaeum. The presence ofO. tyrtaeumwas 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 foundO. tyrtaeumoccurrence 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. tyrtaeumandD. octaedraconsumed more leaf litter per gram of earthworm per day than the nativeE. 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 earthwormO. tyrtaeumonP. cinereuswas 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.
Faculty Members
- Tami S. Ransom - Department of Environmental Studies Salisbury University 1101 Camden Avenue 21801 Salisbury MD USA
Themes
- Effects of earthworms on soil structure and nutrient cycling
- Ecological roles of native and invasive species
- Ecosystem engineering
- Inter-species interactions
- Impact of invasive species on native wildlife
Categories
- Ecology
- Marine sciences
- Geosciences, atmospheric, and ocean sciences
- Biological and biomedical sciences
- Geological and earth sciences nec
- Ecology, evolutionary biology, and epidemiology nec
- Geochemistry
- Ocean marine sciences and atmospheric science
- Geology earth science, general
- Marine biology and biological oceanography
- Geological and earth sciences
- Microbiology and immunology
- Ecology, evolutionary biology, and epidemiology
- Microbiology, general
- Ecology and evolutionary biology