How do campsites, forest fires, and entry point distance affect earthworm abundance in the Boundary Waters Canoe Area Wilderness?
- Published
- Accepted
- Subject Areas
- Conservation Biology, Ecology
- Keywords
- Earthworms, fire, campsites, BWCAW, entry point, lake islands
- Copyright
- © 2019 Wellnitz et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2019. How do campsites, forest fires, and entry point distance affect earthworm abundance in the Boundary Waters Canoe Area Wilderness? PeerJ Preprints 7:e27607v1 https://doi.org/10.7287/peerj.preprints.27607v1
Abstract
Factors controlling the spread of invasive earthworms in Minnesota’s Boundary Waters Canoe Area Wilderness are poorly known. Believed to have been introduced by anglers who use them as bait, invasive earthworms can alter the physical and chemical properties of soil and modify forest plant communities. To examine factors influencing earthworm distribution and abundance, we sampled 38 islands across five lakes to assess the effects of campsites, fire, and entry point distance on earthworm density, biomass and species richness. We hypothesized that all three parameters would be greater on islands with campsites, lower on burned islands, and would decrease with distance from the wilderness entry point. In addition to sampling earthworms, we collected soil cores to examine soil organic matter and recorded ground and vegetation cover. Campsite presence was the single most important factor affecting sampled earthworm communities; density, biomass and species richness were all higher on islands having campsites. Fire was associated with reduced earthworm density, but had no direct effects on earthworm biomass or species richness. Fire influenced earthworm biomass primarily through its negative relationship to groundcover and through an interaction with entry point distance. Distance affected density but no other factor. For islands with campsites, however, distance from the entry point had a counterintuitive effect in that earthworm biomass, which increased with entry point distance.
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Earthworm data collected from BWCA islands, 2016
Physical characteristics include island latitude & longitude, island area (m2), distance from entry point (m), island distance from lake shore, and whether island was burned and had campsites, island distance from lake shore (m). Also included are measured variables: earthworm density (#s/m2) and biomass (g/m2) and species richness; and data from sample sites: ground cover (%) understory vegetation cover (%) and soil organic matter (%).