Site-specific length-biomass relationships of arctic arthropod families are critical for accurate ecological inferences

• Published in: PeerJ
• Main Authors: Versluijs, Tom S. L., Zhemchuzhnikov, Mikhail K., Kutcherov, Dmitry, Roslin, Tomas, Martin Schmidt, Niels, van Gils, Jan A., Reneerkens, Jeroen
• Other Authors: Netherlands Organisation for Scientific Research open grant, Netherlands Organization for Scientific Research (NWO) Polar Program grant, Netherlands Organization for Scientific Research (NWO) Vici grant, Netherlands Organization for Scientific Research (NWO) International Polar Year grant, The Metawad project awarded by Waddenfonds, VEGA grant awarded by the Academy of Finland, ERC-synergy grant awarded by The European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme
• Format: Article in Journal/Newspaper
• Language: English
• Published: PeerJ 2023
• Subjects: Arctic; Greenland; Taimyr; Zackenberg
• Online Access: http://dx.doi.org/10.7717/peerj.15943; https://peerj.com/articles/15943.pdf; https://peerj.com/articles/15943.xml; https://peerj.com/articles/15943.html

Arthropods play a crucial role in terrestrial ecosystems, for instance in mediating energy fluxes and in forming the food base for many organisms. To better understand their functional role in such ecosystem processes, monitoring of trends in arthropod biomass is essential. Obtaining direct measurements of the body mass of individual specimens is laborious. Therefore, these data are often indirectly acquired by utilizing allometric length-biomass relationships based on a correlative parameter, such as body length. Previous studies have often used such relationships with a low taxonomic resolution and/or small sample size and/or adopted regressions calibrated in different biomes. Despite the scientific interest in the ecology of arctic arthropods, no site-specific family-level length-biomass relationships have hitherto been published. Here we present 27 family-specific length-biomass relationships from two sites in the High Arctic: Zackenberg in northeast Greenland and Knipovich in north Taimyr, Russia. We show that length-biomass regressions from different sites within the same biome did not affect estimates of phenology but did result in substantially different estimates of arthropod biomass. Estimates of daily biomass at Zackenberg were on average 24% higher when calculated using regressions for Knipovich compared to using regressions for Zackenberg. In addition, calculations of daily arthropod biomass at Zackenberg based on order-level regressions from frequently cited studies in literature revealed overestimations of arthropod biomass ranging from 69.7% to 130% compared to estimates based on regressions for Zackenberg. Our results illustrate that the use of allometric relationships from different sites can significantly alter the biological interpretation of, for instance, the interaction between insectivorous birds and their arthropod prey. We conclude that length-biomass relationships should be locally established rather than being based on global relationships.