Biology subjects

Cameron, E. K.

Publications and source records attributed to Cameron, E. K..

7 recordsLinked to original sources

bioRxiv2026

A systematic map of soil invertebrate biodiversity in Canada: Identifying spatial and taxonomic knowledge gaps

Soil is one of the most biodiverse habitats on the planet, yet the extent of soil biodiversity knowledge in Canada is unknown. To better understand our knowledge, we systematically mapped soil invertebrate biodiversity knowledge from peer-reviewed literature to identify spatial and taxonomic gaps and to assess whether areas projected to experience different magnitudes of climate change are adequately sampled. A total of 1,176 Canadian sampling locations were identified from 427 articles. We found biases in sampling coverage spatially and in relation to current and projected climatic conditions. The geographic region above 60 degrees North is sparsely sampled. Colder regions (< -0.12 C) and regions receiving the least (< 646.47 mm), moderately high (2268.67 to 2809.40 mm), and high (2809.40 to 3350.14 mm) amounts of precipitation were under sampled. Regions projected to have the smallest (< 0.86 C) and greatest (> 1.59 C) magnitudes in temperature change and regions projected to have moderate (-2.06 to +2.69 mm) to large changes (+2.69 to +7.44 mm) in precipitation were underrepresented. The sampled locations also suffer from taxonomic biases which were skewed toward Nematoda (19%), Annelida (18%), Acari (15%), and Collembola (14%). Our results suggest that methods such as stratified sampling is essential to capture underrepresented regions, taxonomic groups, and an array of current and projected climatic conditions. Additionally, shifting to a multispecies sampling approach is essential for broader soil ecosystem knowledge. Importantly, data from well-sampled areas should be examined to determine how it can be leveraged to advance conservation management of soil invertebrates.

ecology↗

bioRxiv2026

Systematic evidence map of research on life-history traits in native and introduced earthworms

Invasive species constitute one of the most significant threats to biodiversity worldwide, and are responsible for more than $400 billion in losses each year. An organism's life-history strategy, defined by how it allocates resources among growth, survival, and reproduction, plays a central role in determining whether it becomes invasive. While the life-history profiles of aboveground invaders are increasingly well characterised, those of invasive species below ground remain poorly understood. Earthworms are a diverse group of soil invertebrates that can help fill this knowledge gap. Of the ~5,800 earthworm species described to date, nearly 2% are cosmopolitan, meaning they have achieved wide geographic distributions despite limited ability for active dispersal. While life-history traits are likely to contribute to their worldwide distribution, the existing research on earthworm trait variation has not been systematically reviewed. To address this gap, we assessed the taxonomic scope, geographic coverage, and methodologies of studies on earthworm life history traits for species occurring in the US and Brazil, spanning a broad latitudinal range. Our literature search yielded over 8,000 articles across 180 species and revealed that introduced species have received considerably more research attention than native species. Research was concentrated on a few model species, most studies were experimental, and variation in life history traits was most commonly assessed in response to chemical compounds, vermicompost feed type, and environmental factors such as temperature, moisture and soil composition. Variation in adult survival was reported most frequently, followed by adult growth and cocoon production, with the bulk of life history research conducted in India (20%) and China (9%). To better understand the effect invasive earthworm species might have on native fauna, future research on life histories should address taxonomic biases and prioritise detailed study of the life cycles of native species in their natural habitat.

ecology↗

bioRxiv2026

Resurvey of boreal earthworm communities in southern and northern Finland

In northern boreal Europe, the Last Glaciation Maximum resulted in a tabula rasa of earthworm species, post-glacial recolonisation of few peregrine species. Boreal forests represent 11.5% of the Earth's land area, and their cold winters represent the harshest season for earthworms. These biotopes are subject to substantial global changes, notably climate change and land use intensification, which might impact earthworm populations. Yet, no study measuring temporal changes in earthworm population or diversity is known in this biotope. Here, we sampled earthworm communities in two northern and two southern areas in Finland forests. In total, 21 sites were surveyed in 2015 and resurveyed 10 years later in 2025-2026. We aimed at understanding how earthworm diversity and populations changed in the last 10 years, comparing community and species-specific diversity metrics. In ten years, although not significant, earthworm abundance declined (-20%), whereas richness increased (+13%). The cold-tolerant Dendrobaena octaedra decreased, being the only one with a significant change. Temporal community and species dynamics followed a south-north gradient. Southern sites showed a decrease in abundance and D. octaedra populations, with an increase in abundance and occupancy of more heat-tolerant species. Northern sites showed an increase in abundance uniquely due to an increase in D. octaedra populations, but no other species were found there. These changes can be linked to climate changes leading to less rigorous winters in both south and north of Finland, and more rigorous summers in the south, potentially interacting with intense forest management, but could also be attributed to a still ongoing post-glacial recolonisation. These results call for more long-term sampling of earthworm communities in these fragile and rapidly changing environments.

ecology↗

bioRxiv2024

A can of worms: estimating the global number of earthworm species

Estimating the overall species number for a given taxon is a central issue in ecology and conservation biology. This is especially topical for soil organisms, which comprise most known species but whose taxonomy remains largely understudied. Here, we estimated the global number of earthworm species based on the Joppa approach, which models taxonomic effort over time to estimate the total number of known and as yet unknown species in a given taxa. Our Bayesian estimation of the Joppa model suggests a global diversity of the order of 30,000 species, suggesting that the 5,679 earthworm taxa already described only represent around 20% of the actual global species diversity. However, the uncertainty around this estimate is considerable due to severe undersampling and as the model cannot unambiguously decide whether we are describing few species because of a small pool of as yet unknown species, or because of a lack of taxonomic efficiency. Considering the current rate of new species description, we calculate that it would take at least 120 years to describe all the earthworm species existing on Earth, and we discuss thedifferent strategies that should be developed to facilitate and accelerate the discovery and naming of species new to science.

ecology↗

bioRxiv2024

The applicability of Regional Red List assessments for soil invertebrates: First assessment of five native earthworm species in Canada

Earthworms (Annelida: Clitellata: Crassiclitellata) are prominent members of the soil community, important to many ecosystem functions. Despite this, and like many other soil invertebrates, they are rarely considered in conservation assessments, including the IUCN Red List assessments used to assess species extinction risk. To investigate the applicability of the IUCN Regional Red Listing protocol to soil invertebrates, we assessed the conservation status of five earthworm species known to be native to Canada using this protocol and all available occurrence records. In Canada, no earthworm species have yet been assessed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). Due to the lack of data on population sizes and their trends, all five species were assessed using their Extent of Occurrence (EOO) (Criterion B). One species was assessed as Vulnerable, two were assessed in non-threatened categories, and two were assessed as Data Deficient. For the majority, the main threats identified were the continuing loss of potential habitat due to land conversion and resource exploitation, as well as the effects of climate change. Increasing the amount of data, including but not limited to distribution and habitat preferences, would make the assessment process easier and status decisions better supported. By undertaking regional assessments for five native earthworm species in Canada, we show that Regional Red List assessments are feasible for soil invertebrates.

ecology↗

bioRxiv2024

Invasive adult jumping worms in Atlantic Canada are chill-susceptible

The jumping worm Amynthas tokioensis is invasive in North America, and it has been expanding its range northward in recent years. Because low temperatures typically restrict the geographic distribution of organisms, our goal was to characterize the cold tolerance physiology of adult jumping worms from a site in New Brunswick, Canada (c. 45{degrees}N), with the intent of better understanding their geographic range limits. Most of our experiments supported the conclusion that these worms are chill-susceptible: they die during or after exposure to relatively mild low temperatures. When gradually cooled, adult worms lost neuromuscular coordination at approximately 0 {degrees}C and froze at a mean temperature of -4.5 {degrees}C. They did not survive freezing and showed poor survival following 1 h exposures to 0 {degrees}C and subzero temperatures. At higher mild temperatures (5 {degrees}C), the worms could survive short (up to 6 h) but not long (e.g., 48 h) chilling durations. We attempted to induce improved cold tolerance via a five-week gradual acclimation to fall-like temperatures, but fall-acclimated worms showed poor survival during and after this acclimation. Acclimation also did not induce accumulation of glucose, a typical cryoprotectant in earthworms. We suggest that A. tokioensis can likely persist wherever the growing season is sufficiently warm and long enough for the adults to mature, reproduce, and lay cocoons prior to the chilling temperatures associated with early fall. Future work examining the cold tolerance of the overwintering cocoons will be important for fully understanding the northern range limits of these jumping worms.

zoology↗

bioRxiv2022

Towards understanding diversity, endemicity and global change vulnerability of soil fungi

Fungi play pivotal roles in ecosystem functioning, but little is known about their global patterns of diversity, endemicity, vulnerability to global change drivers and conservation priority areas. We applied the high-resolution PacBio sequencing technique to identify fungi based on a long DNA marker that revealed a high proportion of hitherto unknown fungal taxa. We used a Global Soil Mycobiome consortium dataset to test relative performance of various sequencing depth standardization methods (calculation of residuals, exclusion of singletons, traditional and SRS rarefaction, use of Shannon index of diversity) to find optimal protocols for statistical analyses. Altogether, we used six global surveys to infer these patterns for soil-inhabiting fungi and their functional groups. We found that residuals of log-transformed richness (including singletons) against log-transformed sequencing depth yields significantly better model estimates compared with most other standardization methods. With respect to global patterns, fungal functional groups differed in the patterns of diversity, endemicity and vulnerability to main global change predictors. Unlike -diversity, endemicity and global-change vulnerability of fungi and most functional groups were greatest in the tropics. Fungi are vulnerable mostly to drought, heat, and land cover change. Fungal conservation areas of highest priority include wetlands and moist tropical ecosystems.

ecology↗