Biology subjects

Froeslev, T. G.

Publications and source records attributed to Froeslev, T. G..

6 recordsLinked to original sources

bioRxiv2026

Ancient environmental DNA reveals the distinct fingerprints of whaling and climate change on Antarctic marine biodiversity

The Southern Ocean is a disproportionately large contributor to Earth system processes, playing a crucial role in the global transport of carbon, oxygen and heat. It also hosts enormous seasonal biological productivity that supports diverse endemic marine biodiversity. Industrial whaling in the first half of the 20th century and recent human-driven climate change have both profoundly altered Antarctic ecosystems, but ecological surveys of these impacts are limited to well-known taxa in the short period since monitoring began. Here, we analysed five sediment records to reconstruct more than two centuries of ecosystem change across the Western Antarctic Peninsula, spanning periods before and during major human impacts. Environmental DNA metabarcoding of these records revealed substantial biodiversity shifts, with change accelerating in recent decades. We find a significant role for both climate change and whaling in restructuring communities, identifying unique variance in whole-community change explained by each driver. Moreover, we find a negative association between whaling and metazoan families which feed from the water column, suggesting that pre-whaling ecosystems had greater pelagic productivity. Overall, our results reveal baseline Antarctic biodiversity from long before observational records and identify a distinct fingerprint of human drivers in this fragile, rapidly changing ecosystem.

ecology↗

bioRxiv2022

Scrub encroachment promotes biodiversity in wetland restoration under eutrophic conditions

Wetlands are important habitats, often threatened by drainage, eutrophication and suppression of ungulate grazing. In many countries, considerable resources are spent combatting scrub encroachment. Here, we hypothesize that encroachment may benefit biodiversity - especially under eutrophic conditions where asymmetric competition among plants compromises conservation targets. We studied the effects of scrub cover, nutrient levels and soil moisture on richness of vascular plants, bryophytes, soil fungi and microbes in open and overgrown wetlands. We also tested the effect of encroachment, eutrophication and soil moisture on indicators of conservation value (red-listed species, indicator species and uniqueness). Plant and bryophyte species richness peaked at low soil fertility, whereas soil fertility promoted soil microbes. Soil fungi responded negatively to increasing soil moisture. Lidar-derived variables reflecting degree of scrub cover had predominantly positive effects on species richness measures. Conservation value indicators had a negative relationship to soil fertility and a positive to encroachment. For plant indicator species, the negative effect of high nutrient levels was offset by encroachment, supporting our hypothesis of competitive release under shade. The positive effect of soil moisture on indicator species was strong in open habitats only. Nutrient poor mires and meadows host many rare species and require conservation management by grazing and natural hydrology. On former arable lands, where restoration of infertile conditions is unfeasible, we recommend rewilding with opportunities for encroachment towards semi-open willow scrub and swamp forest, with the prospect of high species richness in bryophytes, fungi and soil microbes and competitive release in the herb layer.

ecology↗

bioRxiv2020

Simple attributes predict the importance of plants as hosts to the richness of fungi and arthropods

Consumers constitute the vast majority of global terrestrial biodiversity. Yet, local consumer richness is poorly understood. Plant species richness offers a simple hypothesis to how the diversification of carbon substrates may promote the diversity of arthropods and fungi. We took this one step further and used databases on plant-consumer interaction links to derive the richness of associated biota per plant species (link score). Using a species inventory of 130 sites we investigated 1) how well the link score could be predicted by plant attributes and 2) if the sum of plant species observed or predicted link scores could predict site richness of arthropods and macrofungi better than plant species richness alone. We found plant link scores to be positively related to plant size, abundance, nativeness and ectomycorrhizal status. Link based indices generally improved prediction of richness, stressing the importance of plants as niche space for the megadiverse groups of insects and fungi.

ecology↗

bioRxiv2019

Multi-taxon inventory reveals highly consistent biodiversity responses to ecospace variation

Amidst the global biodiversity crisis, identifying drivers of biodiversity variation remains a key challenge. Scientific consensus is limited to a few macroecological rules, such as species richness increasing with area, which provide limited guidance for conservation. In fact, few agreed ecological principles apply at the scale of sites or reserve management, partly because most community-level studies are restricted to single habitat types and species groups. We used the recently proposed ecospace framework and a comprehensive data set for aggregating environmental variation to predict multi-taxon diversity. We studied richness of plants, fungi, and arthropods in 130 sites representing the major terrestrial habitat types in Denmark. We found the abiotic environment (ecospace position) to be pivotal for the richness of primary producers (vascular plants, mosses, and lichens) and, more surprisingly, little support for ecospace continuity as a driver. A peak in richness at intermediate productivity adds new empirical evidence to a long-standing debate over biodiversity responses to productivity. Finally, we discovered a dominant and positive response of fungi and insect richness to organic matter accumulation and diversification (ecospace expansion). Two simple models of producer and consumer richness accounted for 77 % of the variation in multi-taxon species richness suggesting a significant potential for generalization beyond individual species responses. Our study widens the traditional conservation focus on vegetation and vertebrate populations unravelling the importance of diversification of carbon resources for diverse heterotrophs, such as fungi and insects.

ecology↗

bioRxiv2018

Man against machine: Do fungal fruitbodies and eDNA give similar biodiversity assessments across broad environmental gradients?

The majority of Earths biodiversity is unknown. This is particularly true for the vast part of soil biodiversity, which rarely can be observed directly. Metabarcoding of DNA extracted from the environment (eDNA) has become state-of-the-art in assessing soil biodiversity. Also for fungal community profiling eDNA is seen as an attractive alternative to classical surveying based on fruitbodies. However, it is unknown whether eDNA-metabarcoding provides a representative sample of fungal diversity and census of threatened species. Therefore conservation planning and assessment are still based on fruitbody inventories. Based on a dataset of unprecedented width and depth, representing both soil eDNA-metabarcoding and expert inventorying of fungal fruitbodies, we document for the first time the validity of eDNA as practical inventory method and measure of conservation value for fungi. Fruitbody data identified fewer species in total and per site, and had larger variance in site richness. Focusing on macrofungi - the class Agaricomycetes, and in turn the order Agaricales - metrics of total richness and compositional similarity converged between the methods. eDNA was suboptimal for recording the non-soil dwelling fungi. {beta}-diversity was similar between methods, but more variation in community composition could be explained by environmental predictors in eDNA data. The fruitbody survey was slightly better in finding red-listed species. We find a better correspondence between biodiversity indices derived from fungal fruitbodies and DNA-based approaches than indicated in earlier studies. We argue that (historical) fungal community data based on fruitbody forays - with careful selection of taxonomic groups - may be interpreted together with modern DNA-based approaches.

ecology↗

bioRxiv2017

A systematic survey of regional multitaxon biodiversity: evaluating strategies and coverage

BackgroundIn light of the biodiversity crisis and our limited ability to explain variation in biodiversity, tools to quantify spatial and temporal variation in biodiversity and its underlying drivers are critically needed. Inspired by the recently published ecospace framework, we developed and tested a sampling design for environmental and biotic mapping. We selected 130 study sites (40 x 40 m) across Denmark using stratified random sampling along the major environmental gradients underlying biotic variation. Using standardized methods, we collected site species data on vascular plants, bryophytes, macrofungi, lichens, gastropods and arthropods. To evaluate sampling efficiency, we calculated regional coverage (relative to the known species number per taxonomic group), and site scale coverage (i.e., sample completeness per taxonomic group at each site). To extend taxonomic coverage to organisms that are difficult to sample by classical inventories (e.g., nematodes and non-fruiting fungi), we collected soil for metabarcoding. Finally, to assess site conditions, we mapped abiotic conditions, biotic resources and habitat continuity.\n\nResultsDespite the 130 study sites only covering a minute fraction (0.0005 %) of the total Danish terrestrial area, we found 1774 species of macrofungi (54 % of the Danish fungal species pool), 663 vascular plant species (42 %), 254 bryophyte species (41 %) and 200 lichen species (19 %). For arthropods, we observed 330 spider species (58 %), 123 carabid beetle species (37 %) and 99 hoverfly species (33 %). Correlations among species richness for taxonomic groups were predominantly positive. Overall, sample coverage was remarkably high across taxonomic groups and sufficient to capture substantial spatial variation in biodiversity across Denmark. This inventory is nationally unprecedented in detail and resulted in the discovery of 143 species with no previous record for Denmark. Comparison between plant OTUs detected in soil DNA and observed plant species confirmed the usefulness of carefully curated environmental DNA-data. Species richness did not correlate well among taxa suggesting differential and complex biotic responses to environmental variation.\n\nConclusionsWe successfully and adequately sampled a wide range of diverse taxa along key environmental gradients across Denmark using an approach that includes multi-taxon biodiversity assessment and ecospace mapping. Our approach is applicable to assessments of biodiversity in other regions and biomes where species are structured along environmental gradient.

ecology↗