Antarctic biodiversity predictions through substrate qualities and environmental DNA

Abstract

Antarctic conservation science is crucial for enhancing Antarctic policy and understanding alterations to terrestrial Antarctic biodiversity. Antarctic conservation will have limited long‐term impacts in the absence of large‐scale biodiversity data, but if such data were available, it is likely to improve environmental protection regimes. To enable the prediction of Antarctic biodiversity across continental spatial scales through proxy variables, in the absence of baseline surveys, we linked Antarctic substrate‐derived environmental DNA (eDNA) sequence data from the remote Antarctic Prince Charles Mountains to a selected range of concomitantly collected measurements of substrate properties. We achieved this through application of a statistical method commonly used in machine learning. Our analysis indicated that neutral substrate pH, low conductivity, and certain substrate minerals are important predictors of the presence of basidiomycetes, chlorophytes, ciliophorans, nematodes, and tardigrades. A bootstrapped regression revealed how variations in the identified substrate parameters influence probabilities of detecting eukaryote phyla across vast and remote areas of Antarctica. We believe that our work will improve future taxon distribution modeling and aid in developing more targeted surveys of biodiversity conducted under logistically challenging conditions.

Environment and shipping drive environmental DNA beta‐diversity among commercial ports

“…One of the great strengths of eDNA metabarcoding is, in our opinion, its potential to rapidly and comprehensively survey regions that have been historically under-sampled (Czechowski et al, 2023). It is, however, essential that we do so in a legal, ethical and equitable manner.…”

“…A global effort, in the context of the Convention on Biological Diversity, to clarify the legal and ethical considerations of international transport of eDNA is urgently needed (Lodge, 2022). One of the great strengths of eDNA metabarcoding is, in our opinion, its potential to rapidly and comprehensively survey regions that have been historically under‐sampled (Czechowski et al, 2023). It is, however, essential that we do so in a legal, ethical and equitable manner.…”

Location, location, location: survival of Antarctic biota requires the best real estate

“…While we have well-synchronized geochronology with springtail presence in ice-free conditions in Victoria Land, the Transantarctic Mountains and Dronning Maud Land (figure 2 a ), there are three specific tests that can be carried out to further evaluate the nunatak refuge hypothesis : (1) the Antarctic Peninsula has well-documented springtail records, but their provenance is uncertain [6,29] and age control on LGM and earlier landscapes is sparse [38]—further biological (using robust molecular dating, e.g. [76]) and geochronology are required to evaluate whether nunataks remained ice-free; (2) regions where geochronology indicates that nunataks likely remained ice-free at the LGM (for example in the Prince Charles Mountains; [40,77]), but where, to date, evidence for springtail presence remains equivocal albeit for recent environmental DNA signatures from soils [78]—such biological signals warrant further exploration and (3) greater focus on regions where the geochronology is suggestive of ice-free nunataks at the LGM [35,36,47–51] and biological investigations are limited or yet to be done, for example, in Enderby Land, Ellsworth Mountains and Transantarctic Mountains (figure 2 a ).…”

“…dating, e.g. [76]) and geochronology are required to evaluate whether nunataks remained ice-free; (2) regions where geochronology indicates that nunataks likely remained ice-free at the LGM (for example in the Prince Charles Mountains; [40,77]), but where, to date, evidence for springtail presence remains equivocal albeit for recent environmental DNA signatures from soils [78]-such biological signals warrant further exploration and (3) greater focus on regions where the geochronology is suggestive of ice-free nunataks at the LGM [35,36,[47][48][49][50][51] and biological investigations are limited or yet to be done, for example, in Enderby Land, Ellsworth Mountains and Transantarctic Mountains (figure 2a).…”

The use of different 16S rRNA gene variable regions in biogeographical studies

“…S1 and Table S1). At each location, 500 g of surface soil (0-10 cm) was collected by combining five sub-samples from each plot into sterile Whirl-Pak bags (Nasco, Fort Atkinson, Wisconsin), as described in Czechowski et al (2022), and Czechowski, White, et al (2016), for the Prince Charles Mountains and Reinbolt Hills samples, and in Velasco-Castrill on et al (2014) for the two coastal samples. Soil samples were kept at À20 C right after sampling and stored permanently at À80 C until further processing.…”