How to deal with a bad neighbor? Strategies of sympatric freshwater decapods (Crustacea) for coexistence
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Species with similar niches may exhibit adaptations to diminish competitive pressure and allow sympatry; freshwater decapods are interesting models for the investigations of these strategies. We studied the behavior of two co-occurring decapod species: the anomuran Aegla longirostri and the crayfish Parastacus pilimanus, and investigated the following: (1) whether the species use the stream similarly; (2) if they present zonation within it; (3) if they have different activity levels; and (4) whether their activity patterns overlap. For this, we radio-tracked individuals of both species in their natural environment. Aeglids had larger home ranges than crayfish when considering only the stream. However, crayfish remained in burrows more than in the stream, and the total home ranges did not differ significantly from aeglids. Stream sections used by both species highly overlap, indicating no zonation. Aeglids used the stream more often and more intensively than crayfish, but their diel activity patterns were similar. Despite the lack of zonation in the stream and of temporal segregation, there seems to be some degree of spatial segregation. Differential habitat use seems to be the one of the mechanisms allowing crayfish to coexist with aeglids.
KeywordsAeglids Aquatic environment Competitive exclusion Crayfish Temporal segregation Spatial segregation
We thank CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for the scholarships to JSB, ASG, and AVP, CAPES/FAPERGS (Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul) for the scholarship to MMD, CNPq for the productivity grant to SS (Process no: 308598/2011-3), Idea Wild for donating the equipment, and TM Dias for reading and commenting on the manuscript. We also thank the editor and three anonymous referees for valuable comments and suggestions that improved the quality of the manuscript, and Dr. Miguel Durlo for allowing us to perform the fieldwork in his property.
Conflict of interest
We declare no competing interests.
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