Biology subjects

Wangensteen, O.

Publications and source records attributed to Wangensteen, O..

5 recordsLinked to original sources

bioRxiv2025

From storms to warming seas: a long-term metabarcoding survey in port communities unveils high genetic diversity and ecological resilience of non-indigenous species

Ports are key gateways for the introduction and spread of non-indigenous species (NIS), yet the ecological and genetic temporal dynamics of these introductions remain poorly understood. Long term temporal monitoring is essential to unravel invasion processes, anticipate biodiversity shifts, and inform effective management and biosecurity strategies. In this study, we conducted a five-year (2019-2024) monthly metabarcoding survey in a northwestern Mediterranean port using artificial collectors. By sequencing a fragment of the Cytochrome Oxidase I gene, we identified 2,225 Molecular Operational Taxonomic Units (MOTUs), including 93 NIS. In addition, we examined both interspecific temporal patterns and intraspecific trends of genetic diversity over time. Although NIS accounted for only 4% of total species richness, they represented over 26% of total read abundance, underscoring their strong influence on community structure. Interestingly, NIS had a significantly more homogeneous species composition through time than native species. In 2020, the passage of the Gloria storm reshaped community dynamics, triggering a temporary rise in species richness and MOTU counts, likely due to an influx of native taxa and a gradual decline and increased NIS dominance. Genetic analyses revealed that NIS exhibited higher haplotypic diversity and lower genetic differentiation than native taxa, suggesting sustained gene flow, likely facilitated by maritime transport. MOTUs with longer temporal persistence, particularly among NIS, also showed greater intraspecific diversity, supporting the "insurance hypothesis" and highlighting the role of genetic variability in resilience and invasion success. Overall, our findings showed that NIS, despite their low species richness, maintain high abundances, connectivity, and genetic diversity over time. These attributes likely enhance the NIS ability to persist in dynamic and disturbed port environments, and provide key information for understanding the invasion process. This study highlights the need to integrate genetic diversity metrics into marine biomonitoring assessments and management.

molecular biology↗

bioRxiv2022

Resource competition drives an invasion-replacement event among shrew species on an island

O_LIInvasive mammals are responsible for the majority of native species extinctions on islands. While most of these extinction events will be due to novel interactions between species (e.g. exotic predators and naive prey), it is more unusual to find incidences where a newly invasive species causes the decline/extinction of a native species on an island when they normally coexist elsewhere in their overlapping mainland ranges. C_LIO_LIWe investigated if resource competition between two insectivorous small mammals was playing a significant role in the rapid replacement of the native pygmy shrew (Sorex minutus) in the presence of the recently invading greater white-toothed shrew (Crocidura russula) on the island of Ireland. C_LIO_LIWe used DNA metabarcoding of gut contents from >300 individuals of both species to determine each species diet and measured the size of individuals (weight and length) during different stages of the invasion in Ireland (before, during and after the species come into contact with one another) and on a French island where both species have long coexisted (acting as a natural control site). Dietary composition, niche width and overlap and size were compared in these different stages. C_LIO_LIThe size of the invasive C. russula and composition of its diet changes between when it first invades an area and after it becomes established. Individuals are larger and they consume larger invertebrates at the invasion front, before switching towards the smaller prey taxa that are more essential for the survival of the native species after establishment. As a result, the level of interspecific dietary overlap increases from between 11-14% when they first come into contact with each other to between 39-46% after the invasion. C_LIO_LIHere we show that an invasive species can quickly alter its dietary niche in a new environment, leading to negative impacts that were not previously predicted based on the coexistence of these species in other parts of their mainland ranges. As well as causing the replacement of a native small mammal, the invasive shrew may be rapidly exhausting local resources of larger invertebrate species. These subsequent changes in terrestrial invertebrate communities could have severe impacts further downstream on ecosystem functioning and services. C_LI

ecology↗

bioRxiv2021

Estuarine molecular bycatch as a landscape-wide biomonitoring tool

Environmental DNA analysis is rapidly transforming biodiversity monitoring and bolstering conservation applications worldwide. This approach has been assisted by the development of metabarcoding PCR primers that are suited for detection of a wide range of taxa. However, little effort has gone into exploring the value of the non-target DNA sequences that are generated in every survey, but subsequently discarded. Here we demonstrate that fish-targeted markers widely employed in aquatic biomonitoring can also detect birds and mammals present in the surrounding habitats. We showcase this feature in three temperate estuaries over multiple seasons, where dozens of bird and mammal species offer valuable insights into spatial and temporal faunal variation. Our results indicate that existing metabarcode sequence data sets are suitable for mining and exploration of this molecular by-catch, and that any future eDNA-based surveys can be designed to accommodate this enhanced property of this widely applicable tool.

ecology↗

bioRxiv2020

Space-time dynamics in monitoring neotropical fish communities using eDNA metabarcoding

The biodiverse Neotropical ecoregion remains insufficiently assessed, poorly managed, and threatened by unregulated human activities. Novel, rapid and cost-effective DNA-based approaches are valuable to improve understanding of the biological communities and for biomonitoring in remote areas. Here, we evaluate the potential of environmental DNA (eDNA) metabarcoding for assessing the structure and distribution of fish communities by analysing sediments and water from 11 locations along the Jequitinhonha River catchment (Brazil). Each site was sampled twice, before and after a major rain event in a five-week period and fish diversity was estimated using high-through-put sequencing of 12S rRNA amplicons. In total, 252 Molecular Operational Taxonomic Units (MOTUs) and 34 fish species were recovered, including endemic, introduced, and previously unrecorded species for this basin. Spatio-temporal variation of fish assemblages was detected, richness during the first campaign was nearly twice as high as in the second sampling round; though peaks of diversity were primarily associated with only four locations. No correlation between {beta}-diversity and longitudinal distance or presence of dams was detected, but low species richness observed at sites located near dams indicates that these anthropogenic barriers might have an impact on local fish diversity. Unexpectedly high -diversity levels recorded at the river mouth suggest that these sections should be further evaluated as putative "eDNA reservoirs" for rapid monitoring. By uncovering spatio-temporal changes, unrecorded biodiversity components, and putative anthropogenic impacts on fish assemblages, we further strengthen the potential of eDNA metabarcoding as a biomonitoring tool, especially in regions often neglected or difficult to access.

ecology↗

bioRxiv2019

Fishing for mammals: landscape-level monitoring of terrestrial and semi-aquatic communities using eDNA from lotic ecosystems

O_LIEnvironmental DNA (eDNA) metabarcoding has revolutionised biomonitoring in both marine and freshwater ecosystems. However, for semi-aquatic and terrestrial animals, the application of this technique remains relatively untested.\nC_LIO_LIWe first assess the efficiency of eDNA metabarcoding in detecting semi-aquatic and terrestrial mammals in natural lotic ecosystems in the UK by comparing sequence data recovered from water and sediment samples to the mammalian communities expected from historical data. Secondly, we evaluate the detection efficiency of eDNA samples compared to multiple conventional non-invasive survey methods (latrine surveys and camera trapping) using occupancy modelling.\nC_LIO_LIeDNA metabarcoding detected a large proportion of the expected mammalian community within each area. Common species in the areas were detected at the majority of sites. Several key species of conservation concern in the UK were detected by eDNA in areas where authenticated records do not currently exist, but potential false positives were also identified for several non-native species.\nC_LIO_LIWater-based eDNA samples provided comparable results to conventional survey methods in per unit of survey effort for three species (water vole, field vole, and red deer) using occupancy models. The comparison between survey effort to reach a detection probability of [≥]0.95 revealed that 3-6 water replicates would be equivalent to 3-5 latrine surveys and 5-30 weeks of single camera deployment, depending on the species.\nC_LIO_LISynthesis and Applications. eDNA metabarcoding represents an extremely promising tool for monitoring mammals, allowing for the detection of multiple species simultaneously, and provides comparable results to widely-used conventional survey methods. eDNA from freshwater systems delivers a terrestrial dividend by detecting both semi-aquatic and terrestrial mammalian communities, and provides a basis for future monitoring at a landscape level over larger spatial and temporal scales (i.e. long-term monitoring at national levels).\nC_LI

ecology↗