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. 2024 Apr 18;14(1):8956.
doi: 10.1038/s41598-024-59456-y.

Effects of a beaver dam on the benthic copepod assemblage of a Mediterranean river

T Di Lorenzo  1   2 , A Tabilio Di Camillo  3   4 , E Mori  3   5 , A Viviano  3 , G Mazza  3   5   6 , A Pontalti  3 , M Rogora  7 , B Fiasca  4 , M Di Cicco  4 , D M P Galassi  4
Affiliations

Effects of a beaver dam on the benthic copepod assemblage of a Mediterranean river

T Di Lorenzo et al. Sci Rep. .

Abstract

As known "ecosystem engineers", beavers influence river hydrology, geomorphology, biochemistry, and biological assemblages. However, there is a lack of research regarding the effects of beaver activities on freshwater meiofauna. In this study, we investigated the taxonomic and functional composition of the benthic copepod assemblage of a segment of the Tiber River (Italy) where a beaver dam, created about 7 weeks before our survey, had formed a semi-lentic habitat upstream and a lotic habitat downstream of the dam. We also analyzed the copepod assemblage before and after a flood event that destroyed the beaver dam, providing a unique opportunity to observe changes in a naturally reversing scenario. Our analyses revealed that, while the taxonomic composition and functional traits of the copepod assemblage remained largely unchanged across the recently formed semi-lentic and lotic habitats, substantial differences were evident between the dammed and undammed states. The dammed state showed lower copepod abundances, biomass, and functionality than the undammed one. These results highlight the role of beaver dams in changing the composition and functionality of meiofaunal assemblages offering insights into the dynamic interactions within aquatic ecosystems.

Keywords: Castor fiber; Functional traits; Lotic; Meiofauna; Rodentia; Semi-lentic.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Study area and sampling station. (a) Sansepolcro sampling station, Tiber River in Tuscany (Italy); (b) transects oblique to the river channel upstream (semi-lentic habitat) and downstream (lotic habitat) of the beaver dam and location of the beaver lodge; (c) transects oblique to the river channel in the undammed state (after the dam removal by the flood event at the end of September 2022) and location of the beaver lodge. P1, P2, P3: samples in the semi-lentic habitat; R1, R2, R3: samples in the lotic habitat. Bottom: timeline showing the time setting of the study. The satellite image was obtained from Google Earth Pro vs. 10.46.0.2.
Figure 2
Figure 2
Boxplots illustrating the taxonomic and functional diversity indices. Each boxplot includes median lines, 25–75th percentile boundaries, and whiskers for 10–90th percentiles. Dammed (D) and undammed (UN) states and semi-lentic (SL) and lotic habitats (LR). Margalef’s (d), Pielou’s (J), Shannon’s (H), and Simpson’s (1-λ) indices. Functional Richness (FRic), Functional Evenness (FEve), Functional Divergence (FDiv), Functional Dispersion (FDis).
Figure 3
Figure 3
RQL plot. First axis RQL scores for the environmental (left), trait (central), and species abundance (right) data. Abbreviation as in Tables 1 and 2.
See this image and copyright information in PMC

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