MEPS 483:185-198 (2013)  -  DOI:

Spatial niche differentiation and coexistence at the edge: co-occurrence distribution patterns in Scurria limpets

Moisés A. Aguilera1,*, Nelson Valdivia2, Bernardo R. Broitman1

1Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Facultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile
2Instituto de Ciencias Marinas y Limnológicas and Laboratorio Costero de Recursos Acuáticos Calfuco, Facultad de Ciencias, Universidad Austral de Chile, Campus Isla Teja s/n, Valdivia, Chile

ABSTRACT: Examining the co-occurrence of taxonomically similar species can provide important information about their niches and coexistence. Segregation at smaller scales can be especially relevant for grazers living at the edge of their geographic distribution, because environmental factors can lead to similar distribution. Related grazer species may show dispersive, i.e. uniform, distribution at small scales (few centimetres) to reduce interference among individuals. We examined intra- and interspecific spatial distribution and habitat use in 2 phylogenetically related intertidal limpets, Scurria viridula and S. zebrina, at the polar and equatorial edge of their geographic distribution, respectively, and in S. araucana, a widely distributed species that overlaps the range of the other 2 species across the southeastern Pacific. S. viridula and S. zebrina overlapped in a narrow geographic zone (ca. 250 km) and reached relatively similar densities and sizes. Intraspecific spatial structure estimated through autocorrelation and individual-to-individual distances was random for S. viridula and variable for S. zebrina and S. araucana, depending on the scale considered; S. zebrina was aggregated at the individual-to-individual distances, while S. araucana was mostly random at this scale. Segregated distribution between S. viridula and S. zebrina was observed at the finer scale, whereas the association with S. araucana was random. Abundance of limpets loosely followed major habitats, namely bare rock and the alga Mazzaella laminarioides, which showed patchy distributions. We suggests that similarity in population traits between S. viridula and S. zebrina found in the overlap zone may be compensated by small-scale spatial segregation. Thus, at the edge of their geographic distribution, coexistence between related species may be influenced by spatial niche differentiation driven by habitat suitability or competition.

KEY WORDS: Coexistence · Geographic edge · Grazers · Habitat type · Niche partitioning · Nearest neighbour · Spatial autocorrelation

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Cite this article as: Aguilera MA, Valdivia N, Broitman BR (2013) Spatial niche differentiation and coexistence at the edge: co-occurrence distribution patterns in Scurria limpets. Mar Ecol Prog Ser 483:185-198.

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