Methods for studying earthworm dispersal

Abstract

Dispersal is a key driver of species composition and functional traits in earthworm communities. However, it has been largely overlooked in ecological literature on earthworms because it is particularly difficult to study. In this publication, we review recent developments that have been made in this field of research. We present methods to assess dispersal distance, such as Capture-Mark-Recapture and molecular tools, and methods using dispersal corridors or X-ray imagery aiming at identifying the mechanisms triggering dispersal in earthworms communities.

Blind spots in global soil biodiversity and ecosystem function research

“…Soil macroecologists face many challenges and constraints spanning from a lack of methodological standards and scientific expertize in different taxonomic groups 92 – 94 , to limitations caused by the current implementation of the Convention for Biological Diversity (CBD) and the Nagoya Protocol 95 , 96 . While the first has more immediate, albeit non-trivial solutions (e.g., by expanding the language pool of the researchers and studies included 16 , 97 and by applying common standards for sampling, extraction, and molecular protocols 98 – 101 ), the latter contains systemic issues that go beyond soil ecology alone. In this context, although the CBD and the Nagoya Protocol were created to protect countries while making the transfer of biological material more agile, numerous states have either not yet implemented effective national “Access and Benefit Sharing” (ABS) laws or have implemented very strict regulations 102 , 103 .…”

“…Increase the focus on understudied soil groups (e.g., collembola, acari, protists, mammals) and functions (e.g., soil aggregate stability, bioturbation, nutrient cycling). Establish effective coordination of current networks to support the development of integrated ecological assessments of the soil realm Adoption of available data and methods standards 101 , 132 – 136 and support the establishment and maintenance of data repositories and open access policies. Support open access partnerships (e.g., the German DEAL 137 ) to facilitate knowledge transfer and collaboration across countries and researchers from different backgrounds and expertize.…”

Towards an integrative understanding of soil biodiversity

“…Moreover, we advocate frameworks that incorporate multiple biodiversity theories, as exemplified by metacommunity theory. The roles of movement of soil organisms by both active and passive dispersal also need greater attention in order to understand soil biodiversity patterns (Hirt et al ., ; Mathieu, Caro, & Dupont, ).…”

Methods and approaches to advance soil macroecology

“…For example, within a biogeographical framework of plant host 'islands', Peay et al (2012) use next-generation sequencing of propagules to demonstrate a dispersal limitation of 1 km across a whole ectomycorrhizal fungal community. For earthworms, on the contrary, visual tagging methods (Butt & Lowe, 2007) and X-ray scanning have been used to measure dispersal in addition to molecular methods (Mathieu, Caro, & Dupont, 2018). Using these newer technologies to determine active and passive dispersal of soil organisms will allow movement-based theories of ecology to be tested (Thakur et al, 2019) that contribute to spatial and temporal biodiversity patterns across scales (Dirilgen et al, 2018;Gumiere et al, 2016).…”