0 avis
Trophic niche of the invasive Cherax quadricarinatus and extent of competition with native shrimps in insular freshwater food webs
Archive ouverte
Edité par CCSD ; Springer Verlag -
International audience. Quantifying the trophic niche of non-native species is a valuable way to measure both their invasion success and putative impacts on recipient food webs. Theory predicts that successful invasive species display flexible diet depending on environment conditions, have large trophic niche, and can overlap the trophic niche of functionally similar native species. We investigated these predictions using the redclaw crayfish (Cherax quadricarinatus) as an invasive species model and omnivorous and detritivorous shrimps as native competitors in recently invaded insular Martinican streams (Caribbean region). Although the redclaw crayfish is globally widespread, little is known about its trophic ecology and potential impacts on other crustaceans in its non-native regions. Using stable isotope analyses to quantify the trophic ecology of redclaw crayfish, we found that it occupied a central position in the food webs, with a primary consumer tendency at the population level. Evidence for ontogenetic shifts was found with different trajectories across streams, highlighting its trophic flexibility to environmental conditions. However, redclaw fed on a limited range of resources (small niche sizes) probably due to the local context, characterised by simplified food webs. Crayfish and shrimps shared partly similar food resources (20.5 ± 9.7% of niche overlap with omnivorous shrimps and 14.9 ± 13.8% with detritivorous shrimps). Finally, a slight shift in trophic niche (without niche constriction) of native crustaceans (mainly omnivorous shrimps) was observed when cooccurring with crayfish. Stable isotope analysis revealed here no evidence of striking impact of the newly introduced crayfish on the trophic ecology of native shrimps, but we call for further investigations to assess potential longer-term repercussions on native communities.
Consulter en ligne
Suggestions
Du même auteur
