Length–weight relationships of invasive exotic earthworms in the Huron Mountains forests, Michigan
摘要
Invasive exotic earthworms have been identified as a major ecological threat to forest ecosystems in the Great Lakes region, affecting soil structure, nutrient cycling, and biodiversity. Understanding key biological parameters like body length, weight, growth rate, and regeneration patterns in these earthworms is essential for elucidating their life cycle and ecological impacts on terrestrial ecosystems. In this study, an earthworm survey was conducted in the Huron Mountains of Michigan’s Upper Peninsula. The earthworms were captured from sampling quadrats, identified to species, and their body mass (dry weight) and body length measured. This study established length–weight relationships (LWRs) for invasive exotic earthworm species found in this area. Such relationships elucidate resource allocation and adaptations to different habitats, in turn helping to predict the spread and persistence of these invasive species. Three invasive earthworm species were found in the studied forests: Dendrobaena octaedra, Aporrectodea longa, and Lumbricus terrestris. Lumbricus terrestris exhibited the largest size (X̅ = 60.4 mm long; X̅ = 0.254 g), while D. octaedra was the smallest (X̅ = 25.5 mm long; X̅ = 0.012 g). The LWR regression equations were: W = 0.00001L2.135 for D. octaedra; W = 0.000001L2.816 for A. longa; and W = 0.000003L2.618 for L. terrestris. These findings highlight differences in growth patterns that may be influenced by forest composition and micro-environmental factors. At the same time, earthworms not only reflect environmental conditions but also shape them, as the composition of the worm community can in turn influence forest ecosystem structure and function. This study provided valuable insights into the biological characteristics of invasive exotic earthworms and their potential impacts on North American forest ecosystems.