Benthic assemblages of rock pools in northern Portugal: seasonal and between-pool variability

Abstract

SUMMARY:We investigated the seasonal (winter vs summer and within season) and spatial (between-pool) variability of benthic assemblages of rock pools at mid-intertidal level along the shore of Viana do Castelo (North Portugal). Physical traits of rock pools, including size, depth and position along the shore, were also compared between pools. While pools did not differ for any of the examined physical traits, results indicated a clear seasonal difference in the structure of assemblages, including a total of 49 macroalgal and 13 animal taxa. This finding was driven by six taxa that are more abundant in winter (the reefforming polychaete Sabellaria alveolata, the articulated coralline algae Corallina spp., the brown alga Bifurcaria bifurcata, the encrusting coralline alga Lithophyllum incrustans, the red alga Chondracanthus acicularis and the grazing snails Gibbula spp.) and four algal taxa that are more abundant in summer (the invasive brown Sargassum muticum, the green Ulva spp., the kelp Laminaria ochroleuca and the filamentous red Ceramium spp.). These data provide a new contribution to the knowledge of rock pool systems and have potential implications for monitoring programmes aimed at assessing ecological modifications related to natural and anthropogenic disturbances and for identifying processes responsible for the variability of rock pool assemblages.Keywords: rock pools, rocky intertidal, seasonal variability, benthos, Sabellaria alveolata, Portugal. RESUMEN: Comunidades bentónicas de charcas rocosas del norte de Portugal: variabilidad estacional y entre charcas. -Investigamos la variabilidad estacional (invierno vs verano y entre estaciones) y espacial (entre charcas) de las comunidades bentónicas en charcas rocosas del nivel intermareal medio a lo largo de la costa de Viana do Castelo (Norte de Portugal). Además comparamos los parámetros físicos entre las charcas, incluyendo el tamaño, temperatura y posición a lo largo de la costa. Mientras que las charcas no difieren para ninguno de los parámetros físicos examinados, los resultados indican una clara diferencia estacional en la estructura de las comunidades, las cuales incluyen un total de 49 taxones de algas y 13 de animales. Estos resultados fueron inducidos por seis taxones más abundantes en invierno (el poliqueto formador de arrecifes Sabellaria alveolata, el alga coralinal articulada Corallina spp., el alga parda Bifurcaria bifurcata, el alga coralinal incrustante Litophyllum incrustans, el alga roja Chondracanthus acicularis y los caracoles ramoneadores Gibbula spp.) y cuatro taxones de algas más abundantes en verano (el alga parda invasiva Sargassum muticum, el alga verde Ulva spp., el quelpo Laminaria ochroleuca y el alga roja filamentosa Ceramium spp.). Estos datos contribuyen al conocimiento de las comunidades de charcas rocosas intermareales y tienen potenciales implicaciones en los programas de monitorización enfocados a medir las modificaciones ecológicas relacionadas con alteraciones naturales y antropogénicas y son útiles para identifica...

Structural complexity of macroalgae influences epifaunal assemblages associated with native and invasive species

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“…In the studied shores, the composition of macroalgal assemblages has changed due to the introduction of non-native species over the past decades. Particularly, these shores have progressively been invaded by Sargassum muticum (Yendo) Fesholt, which nowadays is among the most common brown algae in the study area (Bertocci et al, 2012). Potential changes caused by the introduction of invasive macroalgae can be detected by alterations in the associated epifaunal assemblages.…”

Cost-benefit of three different methods for studying Mediterranean rocky benthic assemblages

“…Data are estimated in situ using sub-quadrats (area, Dethier et al 1993, Parravicini et al 2010, Bertocci et al 2012 or point-quadrats (contact points, Foster et al 1991, Dethier et al 1993, Benedetti-Cecchi et al 1996. Data are obtained almost immediately but the results depend on the previous taxonomical knowledge of the diver.…”

Habitat traits and patterns of abundance of the purple sea urchin, Paracentrotus lividus (Lamarck, 1816), at multiple scales along the north Portuguese coast

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