Changes in remnant forest soils and earthworm communities over two decades

• Published in: Applied soil ecology : a section of Agriculture, ecosystems & environment ecosystems & environment, 2024-10, Vol.202, p.105534, Article 105534
• Main Authors: Yesilonis, Ian, Placella, Sarah, Csuzdi, Csaba, Szlavecz, Katalin
• Format: Article
• Language: English
• Subjects: Indirect and direct effects; Invasive species; Pheretimoids; Resampling; Retrospective studies; Urban rural gradient
• ISSN: 0929-1393
• DOI: 10.1016/j.apsoil.2024.105534

Long-term urban soil studies provide details of how urban soils develop over time. Urban soils are affected by regional and local pressures related to air pollution and introduced species such as earthworms and vegetation, which can affect change within relatively short periods of time. In Baltimore, forest soils of an urban–rural gradient were re-sampled, and it was found that, over two decades, calcium (Ca) concentration and pH had increased. These forest soils are habitats for populations of earthworms, which feed on the leaf litter and, consequently, locally alter the forest floor. Given the profound impact that earthworms have on soil properties, changes in soil chemistry were examined to determine any relation to shifts in earthworm community composition and abundance, with a special focus on the invasive jumping worms. To answer this question, earthworm assemblages in urban, suburban, and rural forest patches were sampled in 2002 and 2020. Species biomass and density were determined and then compared to samples collected at the same locations. In 2020, mean biomass and density varied between 91 and 33 g m−2, and 388 and 12 ind m−2, respectively. The results indicate statistically significant correlations between soil properties (pH, Ca, leaf litter depth, and bulk density) and earthworm abundance within a given year. However, changes in soil properties were independent of changes in earthworm species or abundance. The dynamics of earthworm assemblages appear to be different in urban forests than rural ones, with rural forests containing more jumping worms than urban ones, which uniquely affects the forest ecosystems. [Display omitted] •Earthworm diversity and adult density is higher in urban than in rural forests.•Relationships exist between earthworm biomass or density and soil properties.•After 18 years, jumping worm biomass was trending higher in rural forest.