Effects of jumping worms on European earthworms and soil properties

Abstract

Earthworms are ecosystem engineers which alter soil structure and impact other organisms and ecosystem functioning. In 2014, pheretimoid “jumping worms” (Megascolecidae spp.) were discovered in Ontario, Canada, with later discoveries in New Brunswick (2021), and Nova Scotia (2022). Jumping worms are having substantial impacts in the northeastern United States, including effects on nutrient cycling and other soil organisms. In Canada, little research has been done to examine spread or effects of jumping worms since they have established only recently. Thus, we sampled at a residential property in Oromocto, New Brunswick, which was the first location where jumping worms were found in the province. Our objectives were to evaluate: (1) how jumping worms impact soil properties (i.e., nitrogen, carbon); (2) how their presence impacts the abundance of European earthworms; and (3) the effectiveness of two jumping worm sampling methods. We found that jumping worms did not have significant impacts on European earthworm species or soil carbon, but they did have significant impacts on soil nitrogen levels. Our results suggest the existence of a positive relationship between jumping worm abundance and soil nitrogen levels when jumping worm abundance is low. Also, both sampling methods (i.e., mustard solution and wooden discs) were equally effective at detecting the presence of jumping worms at a site. Over the longer term, we hope to track the expansion of this population in order to determine rates of spread.