info:eu-repo/semantics/article
Negative interactions between two SW Atlantic intertidal crabs in soft-bottom habitats
Fecha
2007-12Registro en:
Martinetto, Paulina Maria del Rosario; Valiñas, Macarena Soledad; Palomo, Maria Gabriela; Iribarne, Oscar Osvaldo; Negative interactions between two SW Atlantic intertidal crabs in soft-bottom habitats; Springer; Marine Biology; 151; 12-2007; 1479-1490
0025-3162
CONICET Digital
CONICET
Autor
Martinetto, Paulina Maria del Rosario
Valiñas, Macarena Soledad
Palomo, Maria Gabriela
Iribarne, Oscar Osvaldo
Resumen
The intertidal crabs Chasmagnathus granulatus and Cyrtograpsus angulatus coexists across the SW Atlantic intertidal. Previous studies in this region suggest that C. granulatus displace C. angulatus in soft sediment where C. granulatus build burrows (“burrowing beds”). We examine variation in abundance, size frequency distribution, sex ratio, incidence of autotomies, and diet of both species in C. granulatus crab beds and adjacent areas without burrows. We also experimentally tested the hypothesis that in absence of C. granulatus, C. angulatus will build burrows. Only large sized individuals of C. angulatus venture into C. granulatus crab beds. The sex ratio of C. angulatus was always biased towards females, with higher bias outside crab beds (1:8 outside, 1:2 inside). Although the items consumed in the crab beds did not differed from those consumed outside, the males of C. angulatus had a higher frequency of empty stomachs in crab beds. The incidence of limb autotomies of C. angulatus was higher outside C. granulatus crab bed areas. After a long rainy period in which C. granulatus was absent from these areas, the pattern of habitat use of C. angulatus changed. During this period C. angulatus had higher abundance in the areas, where C. granulatus previously constructed burrows, and there were no differences between areas in any of the measured parameters. In the absence of C. granulatus, C. angulatus built their own burrows and never used C. granulatus burrows. The interaction between C. granulatus and C. angulatus may be a good example of competitive exclusion when the shared resource is the access to surface soft-sediment.