Biometric conversion factors as a unifying platform for comparative assessment of invasive freshwater bivalves

Invasive bivalves continue to spread and negatively impact freshwater ecosystems worldwide. As different metrics for body size and biomass are frequently used within the literature to standardise bivalve-related ecological impacts (e.g. respiration and filtration rates), the lack of broadly applicable conversion equations currently hinders reliable comparison across bivalve populations. To facilitate improved comparative assessment among studies originating from disparate geographical locations, we report body size and biomass conversion equations for six invasive freshwater bivalves (or species complex members) worldwide: Corbicula fluminea, C. largillierti, Dreissena bugensis, D. polymorpha, Limnoperna fortunei and Sinanodonta woodiana, and tested the reliability (i.e. precision and accuracy) of these equations. Body size (length, width and height) and biomass metrics of living-weight (LW), wet-weight (WW), dry-weight (DW), dry shell-weight (SW), shell free dry-weight (SFDW) and ash-free dry-weight (AFDW) were collected from a total of 44 bivalve populations located in Asia, the Americas and Europe. Relationships between body size and individual biomass metrics, as well as proportional weight-to-weight conversion factors, were determined. For most species, although inherent variation existed between sampled populations, body size directional measurements were found to be good predictors of all biomass metrics (e.g. length to LW, WW, SW or DW: R2 = 0.82–0.96), with moderate to high accuracy for mean absolute error (MAE): ±9.14%–24.19%. Similarly, narrow 95% confidence limits and low MAE were observed for most proportional biomass relationships, indicating high reliability for the calculated conversion factors (e.g. LW to AFDW; CI range: 0.7–2.0, MAE: ±0.7%–2.0%). Synthesis and applications. Our derived biomass prediction equations can be used to rapidly estimate the biologically active biomass of the assessed species, based on simpler biomass or body size measurements for a wide range of situations globally. This allows for the calculation of approximate average indicators that, when combined with density data, can be used to estimate biomass per geographical unit-area and contribute to quantification of population-level effects. These general equations will support meta-analyses, and allow for comparative assessment of historic and contemporary data. Overall, these equations will enable conservation managers to better understand and predict ecological impacts of these bivalves.Fil: Coughlan, Neil E.. The Queens University of Belfast; Irlanda. University College Cork; IrlandaFil: Cunningham, Eoghan M.. The Queens University of Belfast; IrlandaFil: Cuthbert, Ross N.. The Queens University of Belfast; Irlanda. Geomar-Helmholtz Centre for Ocean Research Kiel; AlemaniaFil: Joyce, Patrick W. S.. The Queens University of Belfast; IrlandaFil: Anastácio, Pedro. Universidade de Évora; PortugalFil: Banha, Filipe. Universidade de Évora; PortugalFil: Bonel, Nicolás. Université Montpellier II; Francia. Centre National de la Recherche Scientifique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Bradbeer, Stephanie J.. University of Leeds; Reino UnidoFil: Briski, Elizabeta. Geomar-Helmholtz Centre for Ocean Research Kiel; AlemaniaFil: Butitta, Vince L.. University of Wisconsin; Estados UnidosFil: Cadková, Zuzana. Czech University of Life Sciences; República ChecaFil: Dick, Jaimie T. A.. The Queens University of Belfast; IrlandaFil: Douda, Karel. Czech University of Life Sciences; República ChecaFil: Eagling, Lawrence E.. The Queens University of Belfast; IrlandaFil: Ferreira Rodríguez, Noé. Universidad de Vigo; EspañaFil: Hünicken, Leandro Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Johansson, Mattias L.. University of North Georgia; Estados UnidosFil: Kregting, Louise. The Queens University of Belfast; IrlandaFil: Labecka, Anna Maria. Jagiellonian University; PoloniaFil: Li, Deliang. Hunan Agricultural University; ChinaFil: Liquin, Florencia Fernanda. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Marescaux, Jonathan. University of Namur; Bélgica. e-biom; BélgicaFil: Morris, Todd J.. Fisheries and Ocean Canada; CanadáFil: Nowakowska, Patrycja. University of Gdansk; PoloniaFil: Ozgo, Malgorzata. Kazimierz Wielki University; PoloniaFil: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Peribáñez, Miguel A.. Universidad de Zaragoza; EspañaFil: Riccardi, Nicoletta. Consiglio Nazionale delle Ricerche; ItaliaFil: Smith, Emily R. C.. University College London; Estados UnidosFil: Sylvester, Francisco. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentin

Biometric conversion factors as a unifying platform for comparative assessment of invasive freshwater bivalves

Invasive bivalves continue to spread and negatively impact freshwater ecosystems worldwide. As different metrics for body size and biomass are frequently used within the literature to standardise bivalve related ecological impacts (e.g. respiration and filtration rates), the lack of broadly applicable conversion equations currently hinders reliable comparison across bivalve populations. To facilitate improved comparative assessment amongst studies originating from disparate geographic locations, we report body size and biomass conversion equations for six invasive freshwater bivalves (or species complex members) worldwide: Corbicula fluminea, C. largillierti, Dreissena bugensis, D. polymorpha, Limnoperna fortunei and Sinanodonta woodiana, and tested the reliability (i.e. precision and accuracy) of these equations. Body size (length, width, height) and biomass metrics of living-weight (LW), wet-weight (WW), dry-weight (DW), dry shell-weight (SW), shell free dry-weight (SFDW) and ash-free dry-weight (AFDW) were collected from a total of 44 bivalve populations located in Asia, the Americas and Europe. Relationships between body size and individual biomass metrics, as well as proportional weight-to-weight conversion factors, were determined. For most species, although inherent variation existed between sampled populations, body size directional measurements were found to be good predictors of all biomass metrics (e.g. length to LW, WW, SW or DW: R2 = 0.82–0.96), with moderate to high accuracy for mean absolute error (MAE): ±9.14–24.19%. Similarly, narrow 95%–confidence limits and low MAE were observed for most proportional biomass relationships, indicating high reliability for the calculated conversion factors (e.g. LW to AFDW; CI range: 0.7–2.0, MAE: ±0.7–2.0%). Synthesis and applications. Our derived biomass prediction equations can be used to rapidly estimate the biologically active biomass of the assessed species, based on simpler biomass or body size measurements for a wide range of situations globally. This allows for the calculation of approximate average indicators that, when combined with density data, can be used to estimate biomass per geographic unit-area and contribute to quantification of population-level effects. These general equations will support meta-analyses, and allow for comparative assessment of historic and contemporary data. Overall, these equations will enable conservation managers to better understand and predict ecological impacts of these bivalves