Spatial distribution of Echinolitorina peruviana (Lamarck, 1882) for intertidal rocky shore in Antofagasta (23° S, Chile).

Abstract

The intertidal rocky shores in continental Chile have high species diversity mainly in northern Chile (18-27° S), and one of the most widespread species is the gastropod Echinolittorina peruviana (Lamarck, 1822). The aim of the present study is do a first characterization of spatial distribution of E. peruviana in along rocky shore in Antofagasta town in northern Chile. Individuals were counted in nine different sites that also were determined their spectral properties using remote sensing techniques (LANDSAT ETM+). The results revealed that sites without marked human intervention have more abundant in comparison to sites located in the town, also in all studied sites was found an aggregated pattern, and in six of these sites were found a negative binomial distribution. The low density related to sites with human intervention is supported when spectral properties for sites were included. These results would agree with other similar results for rocky shore in northern and southern Chile.

Spatial Distribution of Cyclograpsus cinereus Dana 1851 on the Rocky Shores of Antofagasta (23°27′ S, Chile)

“…This association of an aggregated pattern with negative binomial distribution has been reported by classic literature on benthic fauna [25], as well as by applied entomological studies [22]. The same pattern was reported for inland water crustaceans in Chilean Patagonia [24,26], for intertidal invertebrates on the north Patagonian coast [27], and for the gastropod Echinolittorina peruviana on the rocky shore of Antofagasta [12]. The existence of uniform distribution in four of the 19 sampling events is probably due to interspecific interactions, most likely competition with other species that share the same ecological niche [5][6][7].…”

“…At low tide, intertidal crustaceans, including C. cinereus, form groups under rounded rocks that create a favourable microenvironment [31], whereas at high tide the individuals are dispersed, probably to avoid predation [5,6]. In this scenario, more detailed study is needed to investigate potential migration patterns based on the tides and the day-night cycle [5,6,12,13]. In our study, the samples were collected in the middle of the day at low tide, but future studies could be extended to variations in spatial distribution at different times of day and state of the tide [5,6].…”

“…The sites were selected on rocky beaches with rounded rocks along the seafront of Antofagasta bay [12]. Two of the sites were in a protected zone designated for littoral fishery resource management, in accordance with Chilean law (El Lenguado 1 and El Lenguado 2), where no aquatic resource extraction or culture is permitted; these sites are located at the south end of Antofagasta bay, where there is a very narrow coastal plain with granitic and basaltic rocky shores [12] (Table 1, Figure 1). The other four sites were located within the urban zone of Antofagasta city (Playa Blanca, Las Almejas, Trocadero and Jardines del Norte), where there is a wide coastal plain with basaltic rocky shores.…”