Length-wright relationships of invasive exotic earthworms in the Huron Mountains forests, Michigan

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 biological parameters such as body length, weight, growth rate, and regeneration patterns of these earthworms is crucial first step in comprehending their life cycle and their impacts on ecological processes in 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 were measured. The purpose of the study was to develop the length-weight relationship (LWR) for the invasive exotic earthworm species that appeared in this area. Results showed that three invasive earthworm species were found in the studied forests, and they were: Dendrobaena octaedra , Aporrectodea longa , and Lumbricus terrestris . Among them, L. terrestris exhibited the largest size (mean length: 60.4 mm; mean weight: 0.254 g), while D. octaedra was the smallest (mean length: 25.5 mm; mean weight: 0.012 g). The LWR regression equations were: W = 0.00001L ^2.135 for D. octaedra ; W = 0.000001L ^2.816 for A. longa ; and W = 0.000003L ^2.618 for L. terrestris . These findings highlighted differences in growth patterns that may be influenced by forest composition and micro-environmental factors. This study provided valuable insights into the biological characteristics of invasive exotic earthworms and their potential impacts on North American forest ecosystems.