Patch recolonization by the tunicate Pyura praeputialis in the rocky intertidal of the Bay of Antofagasta, Chile: evidence for self-facilitation mechanisms

Alvarado, Jorge L.; Pinto, Raquel; Marquet, Pablo A.; Pacheco, Cristián; Guíñez, Ricardo; Castilla, Juan Carlos

doi:10.3354/meps224093

Cited by 26 publications

(28 citation statements)

References 27 publications

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“…These include: (1) interference, by providing nursery areas for juveniles which offer protection against predation (for gastropods and decapods, including species which are exploited by intertidal food-gathers; Varas 1996, Fairweather 1991, (2) increasing the chance of survival, by reducing the risk of desiccation for species without external protection (i.e. Polychaeta, Nemertea; Cerda & Castilla 2001), (3) positive interactions among species, since more diverse communities may have enhanced ecosystem functions (Chapin et al 1998, Stachowicz 2001, (4) coexistence mediated by spatial and temporal variation in recruitment (Chesson 1986), given that the disturbance regime and patch dynamics of P. praeputialis in Antofagasta may promote the coexistence of fugitive species, both inside and on top of the ascidian matrices (Alvarado et al 2001, Monteiro et al 2002. Future experimental work should address such issues to understand how the species diversity patterns described here and the role of the P. praeputialis matrices are linked by the mechanisms above.…”

Section: Discussionmentioning

confidence: 99%

Marine ecosystem engineering by the alien ascidian Pyura praeputialis on a mid-intertidal rocky shore

Castilla¹,

Lagos²,

Cerda³

2004

Mar. Ecol. Prog. Ser.

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161

126

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Engineer species transform ecosystems due to their own growth, constitute an integral part of altered environments, and provide new habitats for other species, thus affecting biodiversity and the ecosystem. On rocky shores inside Antofagasta Bay (Northern Chile), the alien ascidian Pyura praeputialis, an engineer species, creates broad belts and dense 3-dimensional matrices that modify the intertidal habitat structure. In all, 116 species of macro-invertebrates and algae inhabit this habitat, compared with the 66 species inhabiting adjacent intertidal rocky shores which lack P. praeputialis. Of the 145 species recorded at the seascape scale (encompassing both mid-intertidal habitat), 55% were found exclusively in intertidal P. praeputialis matrices. Along the coastal gradient, patterns in β-diversity emerge due to the addition of a new set of species to the community inhabiting the P. praeputialis matrices and, to a lesser extent, from spatial turnover. We found differences in the shape of the species frequency distribution between the communities inhabiting the engineered and non-engineered mid-intertidal habitats. However, within the same habitat type, there was no difference in the species frequency distribution between functional groups. Occurrence of macro-algae was not affected by habitat type, but occurence of macro-invertebrates increased significantly in P. praeputialis matrices. P. praeputialis increases species richness at local and seascape scales by providing a novel mid-intertidal habitat which is used by mobile and vagile macro-invertebrates that otherwise would remain excluded from this intertidal level.KEY WORDS: Pyura praeputialis matrices · Ecosystem engineer · Intertidal seascapes · α-and β-diversity · Species frequency distribution · Northern ChileResale or republication not permitted without written consent of the publisher

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Section: Discussionmentioning

confidence: 99%

Marine ecosystem engineering by the alien ascidian Pyura praeputialis on a mid-intertidal rocky shore

Castilla¹,

Lagos²,

Cerda³

2004

Mar. Ecol. Prog. Ser.

Self Cite

161

126

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“…We suggest that in Antofagasta, the described bio-foam also enhances local tunicate settlement, because tadpole larvae of P. praeputialis are in the plankton for Ϸ2 h (18), less than the persistence of the bio-foam associated with P. praeputialis. Furthermore, this may be one of the mechanisms responsible for the as yet unexplained restricted distribution of this free-spawning species inside the Antofagasta Bay, as well as for its high settlement success on adult conspecifics inside the bay (19). Additionally, preliminary field observations in the intertidal rocky shores of Las Cruces and Pelancura (central Chile) have shown that a similar bio-foam production also occurs concurrently with massive gamete spawning of the sunstar Heliaster helianthus and for the chiton Acanthopleura echinata.…”

Section: Resultsmentioning

confidence: 99%

Bio-foam enhances larval retention in a free-spawning marine tunicate

Castilla¹,

Manríquez

Delgado³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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Here we report a mechanism that reduces dispersal of early developing stages and larvae in a free-spawning intertidal and shallow subtidal tunicate, Pyura praeputialis (Heller 1878), in the Bay of Antofagasta, Chile. The spawning of gametes by the tunicate into the naturally turbulent aerated seawater decreases their surface tension and induces the formation of a bio-foam. Water collected from foamy intertidal pools and tide channels showed a high concentration of P. praeputialis early developing stages and tadpole larvae in the foam. Because gametes are synchronically spawned for external fertilization and larvae settle near adults, our results suggest that this bio-foam increases fertilization success and effective settlement of their short-lived larvae in the vicinity of the adults spawning the gametes. This mechanism reinforces published evidence suggesting that local retention of intertidal and inshore marine invertebrate larvae may be more common than previously thought, offering, for instance, new perspectives for the design and networking of marine protected and management areas.Chile ͉ surface tension ͉ tide channels ͉ broadcast spawner ͉ settlement I t is well known that surfactants can induce the formation of bio-foams that can ensure egg retention and larval development in organisms such as tropical leptodactylid frogs (1-5) and African and Asian freshwater labyrinth fishes (6). However, such egg-larval retentive mechanisms or ''foam-nests'' have not been reported for marine organisms. In Chile, massive populations of the intertidal and shallow subtidal tunicate Pyura praeputialis form beds almost exclusively along a 60-70 km stretch of the rocky shoreline inside the Bay of Antofagasta (7). This tunicate is an alien species in Chile, and its absence at locations more than 3-5 km outside of the Bay of Antofagasta, and along the Chilean coast, suggests the existence of unknown mechanisms preventing its dispersal (8) and maintaining high settlement inside the Antofagasta tunicate beds. In December 2004 and January 2005, midway through the ebb tides, we observed massive co-spawning of both eggs and sperm suspension from P. praeputialis into naturally turbulent aerated intertidal seawater (Fig. 1A) and the subsequent formation of localized and conspicuous masses of foams. These bio-foam masses persisted for several hours on top of rocky shores and floating in tidal channels, near where they were spawned, because of onshore winds (Fig. 1). Results and DiscussionTo investigate the role of the bio-foam associated with P. praeputialis on the retention of embryos and tadpole larvae of the species, seawater samples were collected (December 10 and 12, 2004; January 14 and 15, 2005) by using a plankton bilgepump equipped with a 50-m elbow end and calibrated with a domestic flow meter (9). The pump was used to collect water samples at different time intervals through the tide cycle from the sea surface just above or near the intertidal rocky shores in Bay of Antofagasta that are dominated by P. praeputialis. Eac...

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“…ship hulls) and/or sea rafting from extant populations in Australia . Inside the Antofagasta Bay, P. praeputialis shows high densities Alvarado et al 2001). The species is highly competitive for primary substrata , and in the part of the rocky mid-intertidal fringe at Antofagasta outcompetes the native mussel Perumytilus purpuratus.…”

Section: Well-documented Non-indigenous Speciesmentioning

confidence: 97%

Down under the southeastern Pacific: marine non-indigenous species in Chile

et al. 2005

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This article presents the first compilation of marine non-indigenous species (NIS) of algae and macroinvertebrates invading Chilean waters. A total of 32 cosmopolitan and non-cosmopolitan species are reported. Among them there are six species considered as extending their southern range of distribution in connection with El Nin˜o events. The article highlights negative and positive impacts caused by marine NIS invasions. Among the first are Codium fragile var. tomentosoide, considered as a pest in Gracilaria chilensis aquaculture facilities in northern Chile, and Ciona intestinalis, a pest in scallop aquaculture installations. Among the second are bio-engineers species, such as the ascidian Pyura praeputialis and the sea grass Heterozostera tasmanica, which have caused an increase in local biodiversity and enhancement of nursery grounds via the creation of new habitats. Further more, invaders such as the algae Mastocarpus papillosus, Porphyra linearis and P. pseudolinearis represent new exploitable resources, extracted by coastal food gatherers along the coast (M. papillosus) or potential species to develop aquaculture. Additional information is presented on the anemone Anemonia alicemartinae, which appears to be a native species (?), having shown in the past 40-50 years, a geographical southward range extension of approximately 1900 km. The number of NIS reported for Chile is compared with those published for the southwestern Atlantic, South Africa, North America (Atlantic and Pacific coasts) and New Zealand. It is suggested that probably the low number of Chilean NIS is due to the fact that the Chilean coasts are environmentally less stressed than other coasts in the world, due to the scarcity of estuaries, gulfs, enclosed bays, lagoons and low human populations. These kinds of sheltered areas have been suggested as centers for bio-invasions, due to the high rate of human-mediated transfer and increase of pollutants. Furthermore, none of NIS reported from Chile show a fast geographical expansion rate (exception of A. alicemartinae), nor invading strategies such as those described for marine NIS in other latitudes, where notorious ecological unbalances following invasions have been observed. An alternative hypothesis is that the low number of marine NIS invading Chile is underestimated, since the modern list of species generated through specific taxonomically intensive port and harbor surveys is still lacking. Fifteen Biological Invasions (2005) 7: 213-232 Ó Springer 2005 species (five invertebrate and 10 fish) have been deliberately imported to Chile for aquaculture. The invertebrates appear to be controlled within aquaculture facilities and have not established naturalized populations or caused direct ecological impacts on local communities. On the contrary, several millions of salmoniforms (and rainbow trout) have escaped from farming facilities in southern Chile and established naturalized populations. Studies on ecological impacts are lacking. These escapees are also playing a role in the enhancement of ar...

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Patch recolonization by the tunicate Pyura praeputialis in the rocky intertidal of the Bay of Antofagasta, Chile: evidence for self-facilitation mechanisms

Cited by 26 publications

References 27 publications

Marine ecosystem engineering by the alien ascidian Pyura praeputialis on a mid-intertidal rocky shore

Marine ecosystem engineering by the alien ascidian Pyura praeputialis on a mid-intertidal rocky shore

Bio-foam enhances larval retention in a free-spawning marine tunicate

Down under the southeastern Pacific: marine non-indigenous species in Chile

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