1. Trophic Position Stability of Benthic Organisms in a Changing Food Web of an Arctic Fjord Under the Pressure of an Invasive Predatory Snow Crab, Chionoecetes opilio.
- Author
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Zalota, Anna K., Dgebuadze, Polina Yu., Kiselev, Alexander D., Chikina, Margarita V., Udalov, Alexey A., Kondar, Daria V., Mishin, Alexey V., and Tsurikov, Sergey M.
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STABLE isotope analysis , *CRAB populations , *FOOD chains , *STARFISHES , *MARINE ecology , *INTRODUCED species - Abstract
Simple Summary: Impacts caused by alien species are often obscured due to other biotic and abiotic stressors impacting ecosystems worldwide. The introduction of a new predator into a previously undisturbed ecosystem is a rare opportunity to observe such impacts in its pure form. The invasion of the snow crab, Chionoecetes opilio, in Blagopoluchiya Bay of the Kara Sea is a rare natural experiment. The crab settled in the bay in 2014 in high numbers, and up to the present day, this one cohort lives and grows in the bay, causing changes in the taxonomic structure, abundance, and biomass of local benthic communities. The results of stable isotope analysis revealed the stability of the trophic positions and sources of organic material for the most common benthic species as the invasion progressed. As the macrobenthic community of the bay changed, any changes in the prey items of the consumers were within the same trophic level. The food web structure changed, where secondary consumers became more numerous, and the proportion of deposit and suspension feeders decreased. The remaining benthic organisms are less available as food items for the snow crab, which may result in starvation and further decline of the invasive crab population. The introduction of a large predatory snow crab, Chionoecetes opilio, into the Kara Sea is a unique situation where the impact of an invasive species affecting an otherwise undisturbed ecosystem can be observed unhindered by other ecosystem stressors. Trophic interactions are one of the principal relationships between animals and can help assess an ecosystem's stability. The trophic positions and sources of organic material for the most common benthic species of Blagopoluchiya Bay sampled at different stages of the invasion were calculated using stable isotope analysis. The most pronounced changes in the trophic web occurred amongst the megabenthic species, where previously most abundant deposit-feeding ophiuroids have disappeared. However, the benthic species' trophic position and primary production source preference did not change. A sea star, Urasterias lincki, remained the highest carnivore in the bay, and the invasive crab remained at a lower trophic level, showing higher omnivory in its diet. Any changes in the consumers' prey items were within the same trophic level. Overall, active predators became one of the most abundant feeding mode groups. The average weighted trophic position of all megabenthic species increased to the third trophic level, where mostly secondary consumers remained. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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