Auflistung nach Autor:in "Macher, Till-Hendrik"

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Beyond fish eDNA metabarcoding: Field replicates disproportionately improve the detection of stream associated vertebrate species
(2021) Macher, Till-Hendrik; Arle, Jens; Schütz, Robin; Koschorreck, Jan
Fast, reliable, and comprehensive biodiversity monitoring data are needed for environmental decision making and management. Recent work on fish environmental DNA (eDNA) metabarcoding shows that aquatic diversity can be captured fast, reliably, and non-invasively at moderate costs. Because water in a catchment flows to the lowest point in the landscape, often a stream, it can collect traces of terrestrial species via surface or subsurface runoff along its way or when specimens come into direct contact with water (e.g., when drinking). Thus, fish eDNA metabarcoding data can provide information on fish but also on other vertebrate species that live in riparian habitats. This additional data may offer a much more comprehensive approach for assessing vertebrate diversity at no additional costs. Studies on how the sampling strategy affects species detection especially of stream-associated communities, however, are scarce. We therefore performed an analysis on the effects of biological replication on both fish as well as (semi-)terrestrial species detection. Along a 2 km stretch of the river Mulde (Germany), we collected 18 1-L water samples and analyzed the relation of detected species richness and quantity of biological replicates taken. We detected 58 vertebrate species, of which 25 were fish and lamprey, 18 mammals, and 15 birds, which account for 50%, 22.2%, and 7.4% of all native species to the German federal state of Saxony-Anhalt. However, while increasing the number of biological replicates resulted in only 24.8% more detected fish and lamprey species, mammal, and bird species richness increased disproportionately by 68.9% and 77.3%, respectively. Contrary, PCR replicates showed little stochasticity. We thus emphasize to increase the number of biological replicates when the aim is to improve general species detections. This holds especially true when the focus is on rare aquatic taxa or on (semi-)terrestrial species, the so-called 'bycatch'. As a clear advantage, this information can be obtained without any additional sampling or laboratory effort when the sampling strategy is chosen carefully. With the increased use of eDNA metabarcoding as part of national fish bioassessment and monitoring programs, the complimentary information provided on bycatch can be used for biodiversity monitoring and conservation on a much broader scale. © 2021 Author(s)
Environmental DNA-based monitoring of the fish ladder in Dessau-Roßlau
(2023) Macher, Till-Hendrik; Arle, Jens; Schütz, Robin; Beermann, Arne J.; Koschorreck, Jan; Leese, Florian; Wagner, Falko
Fast, reliable, comprehensive, and cost-efficient biodiversity data are needed for environmental assessment and decision making in water management. In this study, we investigated whether eDNA metabarcoding approaches can fulfil these requirements for fish monitoring. We collected 18 water samples of 1 l along a 2 km stretch of the river Mulde (Germany) on a single day in April 2019, in parallel with comprehensive fisheries monitoring conducted over 17 weeks at the fish ladder in Dessau-Roßlau. Additionally, data from Water Framework Directive (WFD) fish monitoring for the years 2017-19 of the same site were available. A total of 33 fish species were detected with all three sampling strategies. The highest number of species was detected with eDNA metabarcoding (28 species), followed by the fish ladder monitoring (27) and the WFD monitoring (22). In direct comparison with the eDNA-based approach, the fish ladder assessment had a higher overlap of detected species (23 of 32 species detected by both methods) than with the WFD monitoring data (19 of 31). While eDNA-based methods are currently limited to assessing species composition, data on abundance and even age composition could also be generated in future. Here, the smart combination of fisheries-based methods with a high spatial and temporal resolution of eDNA metabarcoding can contribute to a better understanding of changes in the ecosystem and thus improve water management. © 2023, Springer Fachmedien Wiesbaden GmbH, ein Teil von Springer Nature.