Soil hosts exceptionally high biodiversity, yet the authors note that the extent of knowledge about soil invertebrate biodiversity across Canada was previously unclear. To address this, the study performed a systematic map of peer‑reviewed literature to identify spatial and taxonomic knowledge gaps and to evaluate whether areas projected to experience varying magnitudes of climate change have been adequately sampled.
The review aims were: to compile locations and taxonomic coverage from published studies, to quantify spatial biases in sampling relative to current climatic conditions and future projections, and to identify underrepresented taxa and regions that require targeted sampling.
The authors screened peer‑reviewed literature and extracted geographic and taxonomic information reported in those studies. From the selected literature they identified a total of 1,176 Canadian sampling locations reported across 427 articles. The systematic map focused on spatial distribution of sampling points, climatic characteristics of sampled sites (temperature and precipitation classes), projected magnitudes of temperature and precipitation change, and taxonomic representation of soil invertebrate groups.
Specific search strategies, inclusion/exclusion criteria, and data extraction protocols were part of the systematic mapping approach as reported in the source. Detailed methodological parameters beyond the counts of articles and sampling locations were not reported in the summary provided here.
The systematic map revealed clear spatial biases in sampling coverage across Canada. The geographic region north of 60° North latitude was sparsely sampled in the peer‑reviewed literature included in the map.
Analyses of sampled sites relative to climatic conditions showed underrepresentation in several classes. Regions characterized by colder mean temperatures (below −0.12 °C) were under sampled. Precipitation classes receiving the least amount of annual precipitation (< 646.47 mm), as well as some higher precipitation classes described as moderately high (2,268.67 to 2,809.40 mm) and high (2,809.40 to 3,350.14 mm), were also under sampled.
When comparing sampling coverage to climate projections, the authors found that areas projected to experience the smallest (< 0.86 °C) and greatest (> 1.59 °C) magnitudes of temperature change were underrepresented. Regions projected to have moderate (−2.06 to +2.69 mm) to large (+2.69 to +7.44 mm) changes in precipitation were similarly under sampled. These gaps indicate limited representation across the range of both current climatic conditions and modeled future changes.
Taxonomic coverage in the mapped literature was uneven. Sampling records were skewed toward a subset of taxa: Nematoda accounted for 19% of records, Annelida 18%, Acari 15%, and Collembola 14%. The source states that other soil invertebrate groups were less frequently sampled or reported, indicating taxonomic bias in the literature.
The skew toward these groups suggests that many soil invertebrate taxa remain underrepresented in Canada’s published sampling record, limiting a comprehensive understanding of soil ecosystem composition and function across diverse regions and climatic scenarios.
Based on identified spatial and taxonomic gaps, the authors recommend adoption of targeted sampling strategies. They emphasize the need for stratified sampling to ensure representation of under sampled geographic regions, climatic conditions, and precipitation and temperature projection classes.
The authors also advocate shifting from single‑taxon studies toward multispecies sampling approaches to broaden knowledge of soil ecosystem structure and function. Such multispecies designs would capture a wider taxonomic breadth and improve the ability to assess community responses to environmental gradients and climate change.
Additionally, the authors suggest that data from well‑sampled areas be examined and potentially leveraged to inform conservation management of soil invertebrates, though specific management actions are not detailed in the source summary.
The authors declared no competing interests. Funding sources reported include the Natural Sciences and Engineering Research Council (NSERC) and internal scholarships and grants from Saint Mary’s University. The preprint was posted on bioRxiv and is available under a CC‑BY‑NC‑ND 4.0 International license. The article citation and DOI were provided in the source.
The systematic map synthesized 427 articles and 1,176 sampling locations and revealed pronounced spatial and taxonomic biases in Canada’s published soil invertebrate literature. High‑latitude regions above 60° North, colder temperature classes, certain precipitation classes, and areas projected to experience small to large changes in temperature and precipitation are underrepresented. Taxonomic records are disproportionately concentrated in Nematoda, Annelida, Acari, and Collembola. The authors conclude that stratified and multispecies sampling approaches are essential to fill knowledge gaps and to improve the utility of soil invertebrate data for conservation and management planning.
Notes: The summary presented here reflects the information provided in the source. Details such as precise search terms, full methodological steps, and taxon‑level lists beyond the major groups noted were not reported in the source excerpt.