Iguá 4225, CP 11400, Montevideo, Uruguay Pilot Programme for ecosystemic monitoring in Cerro Verde (Uruguay): benthic invertebrates as a tool for conservation. PHASE II Full formal report
Igu 4225, CP 11400, Montevideo, Uruguay
Pilot Programme for ecosystemic
monitoring in Cerro Verde (Uruguay):
benthic invertebrates as a tool for
Full formal report
Pilot Programme for ecosystemic monitoring in Cerro Verde
(Uruguay): benthic invertebrates as a tool for conservation
MSc. A. Carranza
The aim of this proposal was to complete baseline studies of biodiversity of
benthic invertebrates at Cerro Verde, Uruguay. To this end, biological samples
were taken seasonally, within a stratified sampling design in the soft bottoms,
from the shallow subtidal (i.e. 3 m to 15 m). To date we completed nine extensive
faunistic surveys, collecting more than 70 taxa of benthic invertebrates in the
intertidal and subtidal zones of the study area. We are now working in the
taxonomic determination of the species recorded, with the aid of specialists in the
different taxa and local students. Some previously unreported species of
invertebrates were found, increasing the knowledge about the coastal biodiversity
of the Atlantic coast of Uruguay. Emerging knowledge will be of outmost
importance in the development of managing strategies for this area, which is a
well known feeding zone for several endangered vertebrate species. Products will
allow detection of environmental impacts in a cheap and rapid way. Divulgation of
the preliminary results were driven through presentation of several works in a
local meeting in June 2007. Part of the information gathered during PHASE I was
already published in mainstream scientific journals, and several more papers are
in preparation. In addition, since Cerro Verde is in process of incorporation to the
National System of Protected Areas (SNAP) as a first Pilot Protected Marine Area
of the in Uruguay, the information here collected will be of utmost importance to
strength the scientific basis for appropriate reserve management.
The increasing need for an adequate environmental management, triggered by the conspicuous degradation of coastal habitats worldwide, has raised awareness of the need for systematic research to asses biodiversity. The need is especially acute for the marine invertebrates, particularly groups that may be sensitive indicators of environmental change. In Uruguay, coastal marine fauna is far from being completely
documented, with little or no systematic effort directed toward taxonomic surveys and inventories of marine invertebrates. This lack of focus is further aggravated by the shortage of experienced field systematists and taxonomists. Worldwide, the importance of detailed taxonomic inventories has been increasingly recognized, since these constitute the basis for the development of ecosystem monitoring programs and the detection of environmental degradation. In this context, fully protected marine reserves
are an emerging tool for marine conservation and management. These areas may provide multiple benefits, including protection of habitat, conservation of biodiversity, insurance about environmental uncertainty and sites for scientific investigation, baseline information, education and recreation. However, data on several key ecological and life history features of marine reserves and communities are needed in order to select the placement and extent of an MPA (marine protected area). In this sense, the aim of this project is to determine benthic invertebrate specific richness in the intertidal and subtidal zone, larval supply from the water column and annual cycles of studied fauna at Cerro Verde, Uruguay, in order to provide a baseline for the evaluation of environmental impacts and to contribute to the design of a MPA.
The biodiversity and productivity of the coastal ecoregion "Uruguay-Buenos Aires Shelf" (34- 41 S), summed to the magnitude of
antrophogenic activities (tourism, urbanisation, industrial and domestic effluents, fisheries), confer to this coastal ecoregion a high priority for conservation. Cerro Verde (33 57'S, 5330' W) is a rocky cape on the east coast of Uruguay affected by semidiurnal, low-amplitude tides (range < 0.5 m) that are largely controlled by wind conditions (direction and speed). The rocky platforms have a smooth slope, with a width ranging from 15 to 23 m, and are exposed to different degrees of
wave action according to its orientation. These platforms follow a classical zonation scheme, in which three zones can be identified: a high intertidal zone dominated by a cyanobacterial film, a middle intertidal zone dominated by barnacles and a low intertidal and shallow subtidal zone characterized by a dense cover of mussels and/or macroalgae. This site harbours a rich hard-substrata benthic fauna, a yet non-defined number of fish species (e.g. endangered sharks Mustelus schmitti, M. fasciatus, Sphyrna bigelowi) and marine birds, mammals (Otaria bryonia, Arctocephalus australis) and sea turtles (Chelonya mydas). This site has recently been established as the first pilot marine protected area in Uruguay. For this purpose, quantitative data on species abundance, distribution, and temporal variation are of outmost importance in order to asses reserve effectiveness. In this context, our proposal was based on the urgent need for this relevant information. In this context, we developed a two years research programme in the area, focused in benthic invertebrates and its planktonic larval stages. This will allow us to asses benthic organism biodiversity and its dynamic at Cerro Verde, providing a baseline for the evaluation of environmental impacts and to contribute to the management of the MPA.
Alvar Carranza is Uruguayan, 35 years old, MSc. in Ecology (2006), Facultad de Ciencias, Universidad de la Repblica, is an advanced PhD. student of PEDECIBA (Basic Sciences Development Programme), since 2007. Previous work includes Project PNUD-GEF-RLA 99-G31 (FREPLATA).
Ana Ins Borthagaray is Uruguayan and aged 31 years old. Four-year BSc, honours in Oceanography (2002), Facultad de Ciencias, Universidad de la Repblica, ia also an advanced PhD. student, since 2006. Previous work includes colaboration with PPNUD-GEF-RLA 99-G31 (FREPLATA). Fabrizio Scarabino is specialist in invertebrate taxonomy. He is currently working at the National Museum of Natural history (Montevideo) and National direction
of Aquatic resources (DINARA). Dra. Estela Delgado is helping with crustacean biology. Dr . Gabriel Genzano (Universidad de Mar del Plata, Argentina) helped with identification of Pycnogonids. Michela Borges from Departamento de Zoologa, Instituto de Biologia, UNICAMP, Sao Paulo, Brazil, helped with taxonomic determination of Ophiuroideans Angel Segura and Luis Rubio are in charge of data processing and field work. Project Karumbe-CIID, an NGO working with sea turtles conservation and ecology in Uruguay provided facilities and contacts with the local community. This NGO is currently developing
conservation projects in the Cerro Verde-La Coronilla area. (http://www.karumbe.8k.com/). Facultad de Ciencias, Universidad de la Repblica, in agreement with the organisation I+D (Investigacin y Desarrollo) is providing facilities for laboratory work. Voucher material is being deposited at the National Museum of Natural History
Field work The Field work was performed with the help of local fishermen and graduate and undergraduate students. Samplings were made onboard the artisanal fishing vessel Dommy, during January, May and September 2007. The fishing gears employed consisted in: a) a bottom
trawl net (BTN) with a 9 m horizontal opening, 1.2 m high and a 25 mm stretched mesh in the cod ends and b) a Piccard epibenthic dredge (PEB), with a horizontal aperture of 60cm and 1cm mesh size. In each date some 9 stations were allocated based on a systematic stratified design, between the outer breaker and aproximatelly 10-15 m depth (see map for details). In each station, 10 minutes tows were performed with the BTN, while 5 min tows were performed with the PEB. The exact location of the stations was determined by Garmin-Etrex Global Positioning System (GPS), depth was noticed usign onboard ECOSONDA. Once landed, all benthic animals collected were fixed and taken to laboratory. Fish was also collected, and stomach
contents kept for subsequent dietary analyses. Voucher material is deposited at the National Museum of Natural History, Montevideo
(MNHNM). Laboratory work Organisms fixed were identified and counted in the laboratory. Taxonomic determination is being made for most of the macrofaunal invertebrates collected since no comprehensive inventory of the benthic fauna is available yet. These imply the collaboration with regional researchers specialized in particular zoological groups, to avoid misidentifications and/or erroneuous taxonomic determination. It is remarkable that at lest three species were first recorded for the Uruguayan coast by means of this strategy (see attached material).
To date, we completed the surveys corresponding to summer, autumn, winter and spring 2007, collecting ca. 50 semi-quantitative samples. During the first survey, (January 2007) we collected 13 macroinvertebrate taxa, being the samples dominated by the crustaceans Loxopagurus loxochelis and Libinia espinosa (45,31 and 26,56% respectively of the collected
individuals). Other taxonomic grouops particularly well represented were molluscs (Pachycymbiola brasiliana, Buccinanops cochlidium and B. duartei), cnidarians (Antholoba achates) and Echinodermata (Mellita quinquiesperforata). Two decapod species, Hepatus pudibundus and
Araneus cribarius were also recorded, together with several species of peracariid crustaceans (Isopoda and Amphipoda). Based on prelim nary observations from the samples collected during the remaining surveys, it is estimated that at leas 50 species of benthic macroinvertebrates were recorded. In adittion, individuals of 18 of bony fishes and 5 chondrictians were captured. From these, Mustelus schmitti Sympterygia acuta are currently listed in the IUCN red list as endangered and threatened respectively. From 153 stomach contents analysed to date, representing 17 fish species, 92.6 % presented some content (Urophysis brasiliensis n=23 (100%), Paralonchurus brasiliensis n=18 (94.1%), Micropogonias furnieri n=31 (90.3%), Macrodon ancylodon n=29 (86.2%), Stromateus brasiliensis n=12 (91.7%) y Sympterygia acuta n=18 (94.1%). P. brasiliensis showed a high number of polychatetes, while S. brasiliensis showed
preferences for small peracarid crustaceans (Mysida). The shrimp Artemesia longinaris was the main item in the remaining species, reaching 78.3% occurrence in Urophysis brasiliensis. The presence of amphipods and fish larvae (16% of ocurrente in Macrodon ancylodon) was also registered. The hermit crab Loxopagurus loxochelis was preyed by Mustelus schmitti and Menticirrus americanus. Stellifer rastrifer, a coastal fish species that inhabits the Tropical and Southwestern Atlantic Ocean is reported for the first time from the Uruguayan Coast and its geographic distribution range is extended southward in more than 1200 km. A warm-circulation event in the zone is suggested as a putative factor explaining the occurrence of the fish in the area.
The lsit of publicatiions to date in peer-reviewed journals and edited books is listed below:
2007: CARRANZA, A, BORGES, M, RODRGUEZ, M & BORTHAGARAY, AI. Ophiuroidea (Echinodermata) from La Coronilla-Cerro Verde (Uruguay): a new record for the Uruguayan coast. Biota Neotropica, 7(3): http://www.biotaneotropica.org.br 2007: CARRANZA, A., BORTHAGARAY, A. I. & GENZANO, G. N. Two new records of pycnogonids on the Uruguayan coast. Brazilian Journal of Biology, 67 (2):373-375
2007: BORTHAGARAY, A. I. & CARRANZA, A. Mussels as ecosystem engineers: Their contribution to species richness in rocky littoral community. Acta Oecologica 31: 243-250 2007: CARRANZA, A. Pilot programme of ecosystem monitoring in Cerro Verde (Uruguay): two years of malacological assessment. Tentacle.The Newsletter of the IUCN/SSC Mollusc Specialist Group, 15: 22-23 2006: SCARABINO, F., ZAFFARONI, JC., CARRANZA, A., CLAVIJO, C. & NIN, M. Gasterpodos marinos y estuarinos de la costa uruguaya: faunstica, distribucin, taxonoma y conservacin. pp 143-155 En Bases para la conservacin y el manejo de la costa uruguaya, Menafra R, Rodrguez-Gallego L, Scarabino F & Conde D (Eds), VIDA SILVESTRE (Sociedad Uruguaya para la Conservacin de la Naturaleza), Montevideo 2006: SCARABINO, F., ZAFFARONI, JC., CLAVIJO, C., CARRANZA, A. & NIN, M. Bivalvos marinos y estuarinos de la costa uruguaya: faunstica, distribucin, taxonoma y conservacin. pp 157-169 En Bases para la conservacin y el manejo de la costa uruguaya, Menafra R, Rodrguez-Gallego L, Scarabino F & Conde D (Eds), VIDA SILVESTRE (Sociedad Uruguaya para la Conservacin de la Naturaleza), Montevideo
In press: CARRANZA, A., SEGURA, A., LPEZ, J. & RUBIO, L. Shell use patterns of the hermit crab Loxopagurus loxochelis (Decapoda: Diogenidae) in the Cerro Verde-La Coronilla marine protected area. Comunicaciones de la Sociedad Malacolgica del Uruguay In adittion, we presented the following posters and abstracts in local meetings (local schools and university) and presentations in regional or local congresses. 2007: CARRANZA, A. Investigacin, monitoreo y conservacin: invertebrados bentnicos del area marina protegida de Cerro Verde (Rocha, Uruguay) IV Congreso Nacional de reas
Protegidas, Trinidad, Uruguay. 2007: RUBIO, L., SEGURA, A. & CARRANZA, A. La comunidad nectnica en el rea marina protegida de Cerro Verde. IV Congreso Nacional de Areas Protegidas ,Trinidad, Uruguay 2005: CARRANZA, A., BORTHAGARAY, A. I. & GENZANO, G. N. Dos nuevos registros de Pycnogonida para aguas Uruguayas. VIII Jornadas de Zoologa del Uruguay, Facultad de Ciencias, Montevideo, Uruguay. 2005: CARRANZA, A. & BORTHAGARAY, A. I. Los mejillones como ingenieros ecosistmicos: su contribucin a la riqueza especifica en la
comunidad del litoral rocoso. II Encuentro de Ecologa del Uruguay, Facultad de Ciencias, Montevideo, Uruguay. Final results will also be presented to the Uruguayan committee of the IUCN and all he people implicated, in different ways, in coastal management The field work was supported by The Maurice Laing Foundation Rufford Small Grant for Nature conservation. SCUBA divers Pablo Priz and Jorge Duran and S. Horta,S. Sauco and Dr. Danilio Calliari are acknowledged for collaboration during field work.
All expenditures were related to the acquisition of material necessary for the development of the project and /or field trips costs. We detail the amount of the funding utilized. We have purchased all necessary equipment.
ITEMS Amount requested () Amount utilized
Travel to and from sampling sites, petrol, car rental, subsistence payment for local fishermen and viatics for 6 persons
Desktop PC 400 400 Digital camera 150 150 Formalin (60 l) 84 84 Alcohol (100 l) 100 100
Plastic bags (500) 28 28 Petri dishes (100) 28 28
Computer disks, paper, ink. 224 224
Bibliographic actualization 500 500
TOTAL 4514 4514
Table: Detail of the amount utilized.
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Ophiuroidea (Echinodermata) from La Coronilla-Cerro Verde (Uruguay): a new record for the Uruguayan coast
Carranza, A. et al.
Biota Neotropica, Vol.7 (number 3): 2007; p. 000-000.
A verso on-line completa deste artigo est disponvel em:On line version of this paper is available at:http://www.biotaneotropica.org.br/v7n3/pt/abstract?article+bn01607032007
Recebido em/ Data Received 22/01/07 - Verso reformulada recebida em/ Revised 30/05/07 - Publicado em/ Accepted 06/09/07
ISSN 1676-0603 (on-line)
Ophiuroidea (Echinodermata) from La Coronilla-Cerro Verde (Uruguay): a new record for the Uruguayan coast
Alvar Carranza1, 2, 4, Michela Borges3, Marcel Rodrguez2 & Ana Ins Borthagaray1, 2
Biota Neotropica v7 (n3) http://www.biotaneotropica.org.br/v7n3/pt/abstract?article+bn01607032007
Data Received 22/01/07 Revised 30/05/07
1Investigacin & Desarrollo, Igu 4225, CP 11400, Montevideo, Uruguay, 2Facultad de Ciencias, Igu 4225, CP 11400, Montevideo, Uruguay
3Departamento de Zoologa, Instituto de Biologia, UNICAMP, CP 6109, CEP 13083-970, Campinas, SP, Brasil, http://www.unicamp.br
4Corresponding author: Alvar Carranza e-mail firstname.lastname@example.org, http://imasd.fcien.edu.uy/, http://www.fcien.edu.uy/
Carranza, A., Borges, M., Rodrguez, M. & Borthagaray, A. I. Ophiuroidea (Echinodermata) from La Coronilla-Cerro Verde (Uruguay): a new record for the Uruguayan coast. Biota Neotrop. Sep/Dez 2007 vol. 7, no. 3 http://www.biotaneotropica.org.br/v7n3/pt/abstract?article+bn01607032007. ISSN 1676-0603.
La Coronilla-Cerro verde has been proposed as the first marine protected area in Uruguay. As part of a detailed benthic biodiversity assessment at the reserve, we analyzed the ophiuroid fauna collected in the intertidal and shallow subtidal during 2005 and 2006. Three species of ophiuroids were identified: Amphioplus lucyae, Amphipholis squamata and Amphiodia sp. Only two species belonging to the genus Amphiodia (A. pulchella and A. planispina) have been previously mentioned for Uruguayan waters, indicating that the unidentified species found in this study constitutes a previously unreported species.
Keywords: Amphiodia, Amphioplus, Amphipholis, Cerro Verde, marine protected area.
Carranza, A., Borges, M., Rodrguez, M. & Borthagaray, A. I. Ophiuroidea (Echinodermata) de La Coronilla-Cerro Verde (Uruguay): un nuevo registro para la costa uruguaya. Biota Neotrop. Sep/Dez 2007 vol. 7, no. 3 http://www.biotaneotropica.org.br/v7n3/pt/abstract?article+bn01607032007. ISSN 1676-0603.
La Coronilla-Cerro Verde ha sido propuesta como la primera rea marina protegida del Uruguay. Como parte de un detallado anlisis de la biodiversidad bentnica dentro de la reserva, se analiz la fauna de ofiuroideos colectada en el intermareal y submareal somero durante 2005 y 2006. Se identificaron tres especies: Amphioplus lucyae, Amphipholis squamata y Amphiodia sp. Solo dos especies del gnero Amphiodia han sido previamente mencionadas para la costa uruguaya (A. pulchella, y A. planispina) indicando que la especie de este gnero encontrada en este estudio corresponde a una especie aun no reportada.
Palabras clave: Amphiodia, Amphioplus, Amphipholis, Cerro Verde, rea marina protegida.
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The increasing need for an adequate environmental management, triggered by the conspicuous degradation of coastal habitats world-wide, has raised awareness of the need for systematic research to asses biodiversity. The need is especially acute for the marine invertebrates, particularly groups that may be sensitive indicators of environmental change (Thomas 1997, Basset et al. 2004). In Uruguay, coastal marine fauna is far from being completely documented, with little or no sys-tematic effort directed toward taxonomic surveys and inventories of marine invertebrates. This lack of focus is further aggravated by the shortage of experienced field systematists and taxonomists (Scarabino 2006). Worldwide, the importance of detailed taxonomic inventories has been increasingly recognized (Gotelli 2004), since these constitute the basis for the development of ecosystem monitoring programs and the detection of environmental degradation.
Among the benthic invertebrates, the Echinodermata comprises nearly 6600 recent species, constituting one of the most important benthic groups worldwide (Hendler et al. 1995). The approximately 2000 species of ophiuroids are among the most widely distributed Echinodermata, occurring from polar regions to the tropics and from the intertidal to the abyssal plain (Hendler et al. 1995). Owing to their ubiquity and abundance, ophiuroids play an important role in energy transfer in benthic ecosystems, linking levels of local trophic webs (Summers & Nybakken 2000).
Previously, the Uruguayan ophiuroidean fauna has been only studied on the continental shelf, from shallow environments (10 m) to 800 m on the slope area (Milstein et al. 1976, Lucchi 1985), with intertidal or shallow subtidal environments receiving little attention. Recently, Scarabino (2006) detailed all invertebrates (except mollusks) reported for Uruguayan shallow waters (i.e. < 50 m), thus providing a basis to distinguish previously unreported species.
In this paper, we analyzed the ophiuroid fauna collected at the in-tertidal and shallow subtidal areas of Cerro Verde. La Coronilla-Cerro verde has been proposed as the first marine protected area in Uruguay, partially due to the existence of several research projects focused in different aspects of its biodiversity. Concerning benthic invertebrates, a detailed faunistic inventory is being performed at the intertidal and subtidal mussel beds and the submarine beach (Carranza & Borthagaray 2005, Carranza et al. 2005, Borthagaray & Carranza in press).
Material and Methods
1. Study area
Cerro Verde (33 57S and 5330 W) is a rocky cape on the east coast of Uruguay (Figure 1). On each side of the cape there are sandy beach arcs that extend 2-3 km. The coast experiences a semidiurnal tide (range < 0.5 m) with the water level influenced mainly by wind conditions (direction and speed). Winds blow south-west during win-ter and north-east during summer. The rocky platforms have a smooth slope, with a width ranging from 15 to 23 m, and are exposed to dif-ferent degrees of wave action according to their orientation. Three zones, following the classical zonation schemes can be identified [on the platform]: a high intertidal zone dominated by a cyanobacterial film, a middle intertidal zone dominated by barnacles and a low in-tertidal and shallow subtidal zone characterized by a dense cover of mussels and/or macroalgae. Subtidal, deeper (>3-4 m) environments are dominated by sandy sediments (Milstein et al. 1976).
2. Sampling design
Sampling was carried out on intertidal and shallow subtidal (i.e. depth < 1.5 m) rocky platforms of the Cerro Verde area dur-
ing February 2005 and February 2006. Three sampling sites 500 m apart were chosen along the coast: 1) exposed, oriented S-SW, 2) intermediate, and 3) protected, oriented N-NE. Within each site, we randomly selected points at each dominance zone (mid intertidal, low intertidal and shallow subtidal), separated by 2 to 10 m. In each point we placed one quadrat of 20 x 20 cm (0.04 m2) and collected all macrofauna and algae present using a metallic hand scrapper. In the shallow subtidal, three points were sampled by SCUBA divers, all in sandy bottoms: at each point, three samples were taken with a plastic corer of 15 cm diameter, each sample consisting in 5 cores. Organisms were fixed with formalin and, in the laboratory, identified and counted. Voucher material is deposited at Museo Nacional de Historia Natural y Antropologa, Montevideo (MNHNM).
A total of 13 specimens of ophiuroids, belonging to 3 species and 1 family (Amphiuridae) were collected. Two specimens were collected in the rocky intertidal and the remaining 11 at the shallow subtidal, in sandy bottoms ranging from 5-7 m depth. A detailed list of the examined material is provided below.
1. Amphioplus lucyae
Tommasi 1971 (Figure. 2 a-c)1.1. Examined material: 2 specimens: Size 2.6 3.8 mm; Habitat:
Shallow subtidal. (MNHNM 1705) 1.2. Disk:Dorsal: Marginal interradial region showing a rectangular (= mar-
ginal) scale slightly larger than adjacent ones; radial shield cuneiform, separated and divergent (Figure 2a). Ventral: oral shields elongated;
South Atlantic Ocean
Ro de la Plata
57 56 55 54 53 52
Figure 1. Map of South American Atlantic coast, showing the study region in the coast of Uruguay. Sampling sites: i1 - i3: intertidal stations; S1 - S3: subtidal stations.
Figura 1. Mapa de la costa Atlntica de Sudamrica, mostrando el rea de es-tudio en la costa Uruguaya. Sitios de muestreo: i1- i3: estaciones intermareales S1- S3: estaciones submareales.
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adoral shields stout and in contact proximally; four contiguous pa-pillae on each side of jaw and a pair of large, triangular, infradental papillae in the tip (Figure 2b,c).
1.3. Arms:Dorsal arm plate trapezoidal (Figure 2a); ventral arm plate
pentagonal; two tentacle scales (Figure 2b,c); four arm spines (Figure 2b).
2. Amphipholis squamata (Delle Chiaje 1828)
(Figure 3 a-c)2.1. Examined material: 2 specimens: Size 1.7-1.9 mm; Habitat:
rocky intertidal (MNHNM 1707) 2.2. Disk:Dorsal: Primary scales not conspicuous; radial shields twice
longer than wide, united. (Figure 3a).Ventral: Oral shields anteriorly pointed, distally curved; adoral
shields proximally in contact two oral papillae on each side of jaw, the distal papilla elongated and rectangular, and larger than the proximal papilla; a pair of elongated infradental papillae at the tip of the jaw (Figure 3b,c).
2.3. Arms:Dorsal arm plate anteriorly pointed and distally curved (Fig-
ure 3a); ventral arm plate pentagonal; two tentacle scales (Figure 3b,c); three arm spines (Figure 3b).
3. Amphiodia sp. A
(Figure 4 a-c)3.1. Examined material. 9 specimens: Size 3.7-5.0 mm; Habitat:
shallow subtidal (MNHNM 1706). 3.2. Disk:Dorsal: Radial shields slightly longer than wider, united
(Figure 4a). Ventral: Oral shields rhomboidal, proximally elongated; adoral
shields in contact proximally; two similar, rounded, oral papillae on each side of the jaw; a pair of rectangular infradental papillae, separated in the tip (Figure 4b,c).
3.3. Arms:Dorsal arm plates rectangular, wider than longer, contiguous
(Figure 4a); ventral arm plates quadrangular, contiguous; two ten-tacle scales (Figure 4b,c); three arm spines, slightly flattened, most notoriously in the ventral-most spine, larger and more compressed (Figure 4b).
No species belonging to the genus Amphiodia other than A. pulchella and A. planispina has been mentioned for Uruguayan waters, indicating that the unidentified species found in this study constitutes a previously unreported species. Milstein and co-workers (1976) mentioned an unidentified species of the genus for the study area. Later, Lucchi (1985) assigned the specimens to A. planispina. Amphiodia sp. share similar characteristics with A. planispina, but differs from this species in showing only one flattened spine, the ventral-most one. A. planispina has three laterally compressed arm spines that are wider below the tip and very blunt. Amphiodia sp. differs of Amphiodia pulchella in several characteristics: size (Amphiodia sp. is larger, its adult reaching 12 mm); adoral shields in contact proximally; dorsal arm plates rectangular (wider than longer) and three arm spines, slightly flattened, most notoriously in the ventral-most spine, larger and most compressed. In addition, A. pulchella is smaller (maximum adult size = 5 mm), presents adoral shields separated proximally and its dorsal arm plates are not rec-tangular. Three arm spines can be identified, but the medial spine is
Figure 2. Amphioplus lucyae: a) dorsal view; b) ventral view; and c) detail of the oral frame. ip - infradental papillae; as - adoral shield; dap - dorsal arm plate; op - oral papillae; os - oral shield; rs - radial shield; rsc- retangular scale; sp - spines; ts - tentacle scale; vap - ventral arm plate.
Figura 2. Amphioplus lucyae: a) vista dorsal;b) vista ventral; y c) detalle del disco oral. ip - papila infradental; as- escudo aboral; dap- placa dorsal del brazo; op - papilas orales; os - escudo oral; rs - escudo radial; rsc - escama re-tangular; sp - espinas; ts - escama tentacular; vap - placa ventral del brazo.
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Figure 4. Amphiodia sp: a) dorsal view; b) ventral view; and c) detail of the oral frame. ip - infradental papillae; as - adoral shield; dap - dorsal arm plate; op - oral papillae; os- oral shield; rs - radial shield; sp - spines; ts - tentacle scale; vap - ventral arm plate.
Figura 4. Amphiodia sp: a) vista dorsal; b) vista ventral; y c) detalle del disco oral. ip - papila infradental; as - escudo aboral; dap- placa dorsal del brazo; op - papilas orales; os- escudo oral; rs - escudo radial; sp - espinas; ts - escama tentacular; vap - placa ventral del brazo.
Figure 3. Amphipholis squamata: a) dorsal view; b) ventral view; and c) detail of the oral frame. ip - infradental papillae; as - adoral shield; dap - dorsal arm plate; op - oral papillae; os - oral shield; rs - radial shield; sp - spines; ts - tentacle scale; vap - ventral arm plate.
Figura 3: Amphipholis squamata. a) vista dorsal; b) vista ventral; y c) detalle del disco oral. ip- papila infradental; as- escudo aboral; dap- placa dorsal del brazo; op- papilas orales; os- escudo oral; rs- escudo radial; sp- espinas; ts- escama tentacular; vap- placa ventral del brazo.
5New Uruguayan record of Ophiuroidea - Biota Neotropica, v7 (n3) - bn01607032007
dorsoventrally flattened, with a truncate, echinulate tip; the other two spines are bluntly rounded. However, until appropriate comparison with specimens for Amphiodia species that have been reported from Brazil and Argentina we will not be able to suggest that it is an unde-scribed species. According to our samples, this species seems to be the more abundant ophiuroid in the area, with maximum estimated densities of 8.66 ind/m2.
To our knowledge, Tommasi et al. (1988b) constitutes the only previous known record of Amphioplus lucyae for the Uruguayan coast (R/V Almirante Saldanha, Station 2865, 34 33 S and 53 12 W). This species was previously reported for southwestern Brazil (Tommasi 1971, 1999, Monteiro 1987, Borges et al. 2002). Tommasi and co-workers (1988a, 1988b), Monteiro (1987, 1990, 1997) and Borges et al. (2002) reported A. lucyae at depths ranging from 8-600 m. We collected this species only in one subtidal sample (depth 5-7 m), suggesting low population densities at the area (maximum density < 5 ind. /m2).
A. squamata is an euribathic, cosmopolitan species, recorded worldwide with Atlantic records from Florida (USA) to Argentina, occurring from 0 to 1330 m (Hendler et al. 1995), and associated to different biological substrata such as algae, bryozoans, and sponges (Borges & Amaral, 2005). Tommasi and co-workers (1988b) already reported this species for the Uruguayan coast, while Milstein and co-workers (1976) reported specimens from subtidal environments of our study area. Alves & Cerqueira (2000) reported intertidal records for this species, as did Bernasconi (1926) for the Argentinean coast. In this study, this species occurred exclusively in the rocky intertidal, associated with mussel banks dominated by Brachidontes rodriguezii and Perna perna, constituting the first record of this species in this particular habitat for the Uruguayan coast. Most likely, the sediment layer occurring between the mussel layer and the rock surface al-lows the presence of ophiuroids. This species seems to be rare in the mussel banks of the study area, as indicated by the low frequency of occurrence (0.01% of total intertidal samples).
We strongly stressed the need for detailed taxonomic studies on other benthic invertebrates at the study area, aiming to provide a precise taxonomic inventory of the benthic fauna within the reserve area.
The field work was supported by The Maurice Laing Foundation Rufford Small Grant for Nature conservation. SCUBA divers Pablo Priz and Jorge Duran and Dr. Danilio Calliari are acknowledged for collaboration during field work. We also thank F. Scarabino for the valuable comments made on an earlier version of the manu-script. Our thanks to the Departamento de Zoologia, Instituto de Biologia, UNICAMP, for the facilities and assistance with figures. Two anonymous reviewers are acknowledged for their very helpful suggestions.
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Salvador (Bahia, Brasil). Rev. Bras. Zool. 17:543-553.
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BORGES, M. & AMARAL, A.C.Z. 2005. Classe Ophiuroidea.. In Manual de Identificao dos Invertebrados Marinhos da Regio Sudeste-Sul do
Brasil. (A.C.Z. AMARAL, A.E. RIZZO & ARRUDA, E.P. eds). Vol. I. EDUSP Ed. So Paulo. p.238-272
BORGES, M., MONTEIRO, A.M.G. & AMARAL, A.C.Z. 2002. Taxonomy of Ophiuroidea (Echinodermata) from the continental shelf and slope of the Southern and Southeastern brazilian coast. Biota Neotropica, 2:1-69 http://www.biotaneotropica.org.br/v2n2/pt/fullpaper?bn02302022002_1+pt (last accesss in 14/12/2006).
BORTHAGARAY, A.I. & CARRANZA, A. In press. Mussels as ecosystem engineers: Their contribution to species richness in rocky littoral com-munity. Acta Oecol. Int. J. Ecol.
CARRANZA, A. & BORTHAGARAY, A.I. 2005. Los mejillones como ingenieros ecosistmicos: su contribucin a la riqueza especifica en la comunidad del litoral rocoso. Publ. Esp. Soc. Zool. Uruguay. Act. VIII. Jorn. Zool. Uruguay. 65 [Abstract]
CARRANZA, A., BORTHAGARAY, A.I. & GENZANO, G.N. 2005. Dos nuevos registros de Pycnogonida para aguas Uruguayas. Publ. Esp. Soc. Zool. Uruguay. Act. VIII. Jorn. Zool. Uruguay. 49 [Abstract].
GOTELLI, N.J. 2004. A taxonomic wish-list for community ecology. Philos. Trans. R. Soc. Lond., B, Biol. Sci. 359:585-597.
HENDLER, G., MILLER, J.E., PAWSON, D.L. & KIER, P.M. 1995. Sea stars, sea urchins and allies: echinoderms of Florida and the Caribbean. Smithsonian Institution Press, Washington.
LUCCHI, C. 1985. Ophiuroidea (Echinodermata) del frente martimo uru-guayo hasta 800 m de profundidad, con claves para su reconocimiento. Contrib. Depto. Oceanogr. (F.H.C), Montevideo, 2:115-171.
MILSTEIN, A., JUANIC, M. & OLAZARRI, J. 1976. Algunas asociaciones bentnicas frente a las costas de Rocha, Uruguay. Resultados de la cam-paa del R/V Hero, viaje 72-3a. Com. Soc. Malac. Urug. 4:143-164.
MONTEIRO, A.M.G. 1987. Ophiuroidea (Echinodermata) da regio de Ubatuba (SP) - Aspectos morfolgicos e ecolgicos. Tese de Doutorado, Universidade de So Paulo, So Paulo.
MONTEIRO, A.M.G. 1990. Ophiuroidea (Echinodermata) in the coastal system of the State of So Paulo (Brazil). In Anais II Simpsio de Ecos-sistema da Costa Sul e Sudeste Brasileira: Estrutura, Funo e Manejo, v.1. guas de Lindia, p.186-201.
MONTEIRO, A.M.G. 1997. Ocorrncia de Ophiuroidea (Echinodermata) na plataforma do Estado de So Paulo. In Boletim de Resumos Expandidos VII COLACMAR, Santos, v.2, p.182-183.
SCARABINO, F. 2006. Faunstica y taxonoma de invertebrados bentnicos marinos y estuarinos de la costa uruguaya. In Bases para la conservacin y el manejo y de la costa uruguaya (R. Menafra, L. Rodrguez-Gallego, F. Scarabino & D. Conde, eds). VIDA SILVESTRE (Sociedad Uruguaya para la Conservacin de la Naturaleza), Montevideo, p.113-142.
SUMMERS, A.C. & NYBAKKEN, J. 2000. Brittle star distribution patterns and population densities on the continental slope off Central California (Echinodermata: Ophiuroidea). Deep Sea Res. Part II Top. Stud. Ocea-nogr. 47:1107-1137.
THOMAS, J.D. 1997. Using Marine Invertebrates to Establish Research and Conservation Priorities. In Biodiversity II: Understanding and Protect-ing Our Biological Resources (M. L. Reaka-Kudla, D. E. Wilson, E. O. Wilson, eds.) Joseph Henry Press, London, p.357-370.
TOMMASI, L.R. 1971. Equinodermes do Brasil. I. Sobre algumas novas espcies e outras pouco conhecidas para o Brasil. Boletim do Instituto Oceanogrfico, Universidade de So Paulo, 20:1-21;
TOMMASI, L.R., CASTRO, S.M. & SOUSA, E.C. 1988a. Echinodermata coletados durante as campanhas oceanogrficas do N/Oc. Almirante Saldanha no Atlntico Sul Occidental. Relat. Interno Inst. Oceanogr. Univ. Sao Paulo. 21:1-11
TOMMASI, L.R. 1999. Echinodermata Recentes e Fsseis do Brasil. http://www.bdt.org.br/zoologia/echinodermata/ 12/12/2005
TOMMASI, L.R., CERNEA, M.C.W. & CONDEIXA, M.C.G. 1988b. Equi-nodermes coletados pelo N/Oc. Almirante Saldanha entre 26 59 S e 38 39 S. Relat. Interno Inst. Oceanogr. Univ. Sao Paulo. 22:1-11
Braz. J. Biol., 67(2A): 631-637, 2007
ID Artigo: 117-05 envio: 09/03/2007
cubomultimidia publicaes e-mail: email@example.com
Two new records of pycnogonids on the uruguayan coast
Carranza, A.a*, Borthagaray, AI.a and Genzano, GN.a,b
aInvestigacin & Desarrollo, Facultad de Ciencias Exactas, Universidad de la Repblica, Igu 4225, CP 400, Montevideo, Uruguay
bDepartamento de Ciencias Marinas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3250 (7600) Mar del Plata, Argentina
Received September 8, 2005 Accepted May 0, 2005 Distributed May , 2007
(With 2 figures)
The Pycnogonida from Uruguayan waters are scarcely known, and their reports are markedly discontinuous. In this paper, several individuals of two previously unrecorded pycnogonids at the shallow rocky subtidal and lower intertidal fringes of Cerro Verde (Rocha, Uruguay) are reported. The specimens were assigned to Pycnogonum pamphorum Marcus, 940 and Anoplodactylus petiolatus (Kroyer, 844). This is the first record of these species on the Uruguayan coast and the southernmost record of P. pamphorum, previously recorded only in Santos, Brazil (type locality).
Keywords: Pycnogonida, Pycnogonum, Anoplodactylus, Uruguay.
Dois novos registros de pycnogonida para a costa uruguaia
Pouco se conhece da fauna dos Pycnogonida de guas Uruguaias, e seus registros so marcadamente descontnuos. Neste trabalho, so reportados vrios indivduos de dois picnogondeos no registrados previamente, nas faixas ro-chosas submareal rasa e bordas intermareais baixas de Cerro Verde (Rocha, Uruguai). Os espcimes foram atribudos s espcies Pycnogonum pamphorum Marcus, 940 e Anoplodactylus petiolatus (Kroyer, 844). Este o primeiro registro dessas duas espcies para a costa Uruguaia e constitui o registro mais austral para P. Pamphorum, conhecido previamente somente em Santos, Brasil (localidade tipo).
Palavras-chave: Pycnogonida, Pycnogonum, Anoplodactylus, Uruguai.
Pycnogonids or sea spiders are quite common in many different marine habitats, from the intertidal zone to the abyssal depths. However, they are seldom seen due to their small size and cryptic coloration (Bain, 99).
On the Uruguayan coast, the pycnogonids are largely unknown, with the available literature referring only to the larger and more conspicuous species, such as the members of the genus Colossendeis. In this vein, C. geofroyi Mae-Garzn, 944 was originally described from Uruguayan specimens and received further atten-tion by Laramendy (974), who analyzed material from R/V Walter Hewig cruise in the Uruguayan continen-tal shelf. Stock (966) reported not only this species but also Tanystylum isthmiacum difficile Stock, 955, Nymphon sp. and Pycnogonum elephas (Stock, 966) for the South American Atlantic coast based on material col-lected by the R/V Calypso. Additionally, Juanic and Rodrguez-Moyano (976) reported the presence of uni-
dentified pycnogonids associated with banks of Mytilus edulis platensis.
However, intertidal pycnogonids have never been re-ported on the Uruguayan coast. In this paper, as part of a project dealing with benthic invertebrates biodiversity, two species found in the rocky intertidal of Cerro Verde (Rocha, Uruguay) are reported.
2. Material and Methods
2.1. Study area
Cerro Verde (33 57 S and 53 30 W) is a rocky cape on the east coast of Uruguay (Figure ). On each side of the cape there are sandy beach arcs that extend for 2-3 km. The coast experiences a semidiurnal tide (range
Carranza, A., Borthagaray, AI. and Genzano, GN.
Braz. J. Biol., 67(2A): 631-637, 20072
platforms have a smooth slope, with a width ranging from 5 to 23 m, and are exposed to different degrees of wave action according to its orientation. In these, three zones, following the classical zonation schemes, can be identified: a high intertidal zone dominated by a cyanobacterial film, a middle intertidal zone dominated by barnacles and a low intertidal and shallow subtidal zone characterized by a dense cover of mussels and/or macroalgae.
2.2. Sampling design
Sampling was carried out on intertidal and shallow subtidal (i.e. depth
Two new records of pycnogonids for Uruguay
Braz. J. Biol., 67(2A): 631-637, 2007 3
Acknowledgments The field work was supported by The Maurice Laing Foundation Rufford Small Grant for Nature conservation. A.C. acknowledges financial support from CSIC. A.I.B. thanks the Cleveland Metroparks Zoo for funding received. We also thank F. Scarabino and Marcos Lhano for the valuable comments made on an earlier version of the manuscript.
BAIN, BA. Some observations on biology and feeding behavior in two southern California pycnogonids, Bijdr. Dierk., 99, vol. 6, no. , p. 63-64.
CALIARI D., DEFEO O., CERVETO, G., GMEZ, M., JIMNEZ L., SCARABINO, F., BRAZEIRO, A. and NORBIS, W. Marine life of Uruguay: critical update and priorities for future research. Gayana, 2003, vol. 67, no. 2, p. 34-370
GENZANO, GN. Associations between pycnogonids and hydroids from the Buenos Aires littoral zone, with observations on the semi-parasitic life cycle of Tanystylum orbiculare (Ammotheidae). Sci. Mar., 2002, vol. 66, no. , p. 83-92
JUANIC, M. and RODRGUEZ-MOYANO, M. Composicin faunstica de la comunidad de Mytilus edulis platensis dorbigny,
846 ubicada a unas 55 millas al SE de La Paloma. Com. Soc. Mal. Uruguay, 976, vol. 4, no. 29, p. 3-6.
LARAMENDY, ML. Anotaciones sobre Colossendeis geofroyi (Mae-Garzn, 944). Neotrpica, 974, vol. 20, no. 63, p. 49-52
MARCUS, E. Os pantopoda brasileiros e os demais sul-americanos. Bol. Fault. Fil., Cien., Letr., 940, vol. 9, no. 4, p. 3-44.
STAPLES, DA. Pycnogonum (Pycnogonida: Pycnogonidae) from Australia with descriptions of two new species. Mem. Mus. Victoria. 2002, vol. 59, no. 2, p. 54-553
STAPLES, DA. and WATSON, JE. Associations between pycnogonids and hydroids, In: J. Bouillon, F. Boero, F. Cicogna and P. F. S. Cornelius (eds.), Modern Trends in the Systematics, Ecology, and Evolution of Hydroids and Hydromedusae, Oxford University Press, 987, p. 25-226.
STOCK, JH. Rsultats scientifiques des campagnes de la Calypso. Fascicule VII. Campagne de la Calypso au large des cotes atlantiques de lAmerique du Sud (96-962). I. 4 Pycnogonida. Ann. Inst. Oceanogr. Monaco, 966, vol. 44, p. 385-406.
ava i lab le at www.sc ienced i rec t . com
journa l homepage : www. e lsev ier . com/ loca te /ac toec
a c t a o e c o l o g i c a 3 1 ( 2 0 0 7 ) 2 4 3 2 5 0
Mussels as ecosystem engineers: Their contribution tospecies richness in a rocky littoral community
Ana Ines Borthagaray*,1, Alvar Carranza1
Investigacion and Desarrollo, Facultad de Ciencias, Igua 4225, CP 11 400, Montevideo, Uruguay
a r t i c l e i n f o
Received 23 December 2005
Accepted 17 October 2006
Published online 9 April 2007
a b s t r a c t
Mussels are important ecosystem engineers in marine benthic systems because they ag-
gregate into beds, thus modifying the nature and complexity of the substrate. In this study,
we evaluated the contribution of mussels (Brachidontes rodriguezii, Mytilus edulis platensis,
and Perna perna) to the benthic species richness of intertidal and shallow subtidal commu-
nities at Cerro Verde (Uruguay). We compared the richness of macro-benthic species be-
tween mussel-engineered patches and patches without mussels but dominated by algae
or barnacles at a landscape scale (all samples), between tidal levels, and between sites dis-
tributed along a wave exposition gradient. Overall, we found a net increase in species rich-
ness in samples with mussels (35 species), in contrast to samples where mussels were
naturally absent or scarce (27 species). The positive trend of the effect did not depend
upon tidal level or wave exposition, but its magnitude varied between sites. Within sites,
a significant positive effect was detected only at the protected site. Within the mussel-
engineered patches, the richness of all macro-faunal groups (total, sessile and mobile)
was positively correlated with mussel abundance. This evidence indicates that the mussel
beds studied here were important in maintaining species richness at the landscape-level,
and highlights that beds of shelled bivalves should not be neglected as conservation targets
in marine benthic environments.
2007 Elsevier Masson SAS. All rights reserved.
Ecosystem engineering (i.e. the creation, modification and
maintenance of habitats by organisms (Jones et al., 1994) gen-
erates environmental heterogeneity and increases the diver-
sity of habitats at the landscape level (Jones et al., 1997).
Such increases in habitat diversity suggests that ecosystem
engineers can positively affect ecosystem species richness.
However, two conditions must be met to achieve higher
species richness at this spatial scale. First, the engineer spe-
cies must provide conditions not present elsewhere in the
landscape and, second, some species must be able to live
only in the engineered patches (Wright et al., 2002). Only if
the engineer-created patches are sufficiently different from
its surroundings (so that species otherwise excluded from
the landscape can persist) will the addition of an engineer in-
crease species richness via an increase in habitat diversity
(Wright et al., 2002). This newly developed conceptual
* Corresponding author. Tel./fax: 598 2 5258 61821.E-mail address: firstname.lastname@example.org (A.I. Borthagaray).
1 Both authors contributed equally.1146-609X/$ see front matter 2007 Elsevier Masson SAS. All rights reserved.doi:10.1016/j.actao.2006.10.008mailto:email@example.com://www.elsevier.com/locate/actoec
a c t a o e c o l o g i c a 3 1 ( 2 0 0 7 ) 2 4 3 2 5 0244
framework is a well-suited tool for management and monitor-
ing issues, since it relates habitat-forming species with pro-
cesses maintaining local and regional biodiversity.
Ecosystem engineers can affect the availability of re-
sources to other organisms either as a direct consequence of
the structure created by them or by the modulation of biotic
or abiotic forces by its structure (Jones et al., 1994, 1997) or
their biological activity (e.g. Commito and Boncavage, 1989).
Shell production and the subsequent creation of habitat by
aquatic molluscs can affect other organisms via three general
mechanisms, namely the provision of substrata for attach-
ment, the provision of refuges to avoid predators or physical
or physiological stress, and the control of the transport of par-
ticles and solutes in the benthic environment (Gutierrez et al.,
2003). Mussels are known to control the above factors and pro-
cesses in marine benthic environments (Frechette et al., 1989;
Crooks and Khim, 1999) suggesting that they can provide other
organisms with unique resources. However, their effects on
the macro-faunal community may depend upon habitat fea-
tures varying along exposure and tidal gradients and with
the spatial scales considered, since a high variability in
the abundance of organisms at spatial scales within and
among shores has been found in several intertidal studies
(Benedetti-Cecchi, 2001a; Benedetti-Cecchi et al., 2001b;
Adami et al., 2004).
Mussel beds are a conspicuous feature of Uruguayan rocky
shores. Brachidontes rodriguezii is the dominant mussel species
in these beds but Mytilus edulis platensis and Perna perna are
also present (Maytia and Scarabino, 1979; Neirotti, 1981).
Although the biodiversity of Uruguayan rocky intertidal
shores is comparatively well known (Caliari et al., 2003), mus-
sel beds have only been studied at the population level, and
specifically in relation to the commercial harvesting of some
species (Riestra et al., 1992). On the other hand, the contribu-
tion of mussels to the structure and species richness of inter-
tidal and subtidal communities has received little attention in
this region. Nevertheless, this is particularly important since
intensive mussel harvesting might result in the loss of other
species relying on critical resources only available at the
In this paper we assessed the contribution of mussel-
created habitat to the species richness of the benthic intertidal
and shallow subtidal community at a Uruguayan rocky shore.
In particular we quantified differences in macro-benthic spe-
cific richness between mussel-engineered patches (hereafter
namely MEP) and non-mussel-engineered patches (hereafter
namely NMEP) dominated by algae or barnacles and evaluated
the consistency of the engineering effect across environmen-
tal gradients and different spatial scales. Further, we also
focused on how species richness depends upon individual
shell traits and spatial arrangement of shells.
2. Materials and methods
2.1. Study area
Cerro Verde (33570S, 53300W) is a rocky cape on the east coast
of Uruguay (Fig. 1) affected by semidiurnal, low-amplitude
a c t a o e c o l o g i c a 3 1 ( 2 0 0 7 ) 2 4 3 2 5 0 245
tidal level varied, but ensured at least a minimum degree of
replication within each condition in order to examine the
main contrasts of interest. Organisms collected were fixed
and identified and counted in the laboratory. In addition, all
the mussels collected were counted, measured (shell length
to the nearest 0.1 mm), oven-dried (40 C over 48 h) and
weighed to the nearest 0.01 g.
2.3. Data analysis
Each macro-faunal species was assigned to the following cat-
egories according to its occurrence: generalists (present in
both MEP and NMEP); MEP specialists; and NMEP specialists.
Sample-based rarefaction curves were constructed for MEP,
NMEP and total (i.e. landscape) for meaningful standardiza-
tion and comparison of datasets (Gotelli and Entsminger,
2001). Then, we calculated the following parameters in order
to describe and quantify the engineers effect: Landscape
Area Engineered (LAE) (calculated as percentage of MEP/total
patches); Relative Habitat Richness (RHR) as engineered
richness/unengineered richness; Landscape Richness En-
hancement (LRE) as [Engineered specialists / (Unengineered
specialists Generalists)] 100]; Landscape Insurance Poten-tial (LIP) as percentage of generalists; and Habitat Rescue Po-
tential (HRP) as percentage of generalist species whose mean
abundance (density in patch) and incidence (number of
occurrences) was at least two times greater in engineered
patches than in unengineered patches. Statistical significance
of differences in abundance were assessed by means of
KolmogorovSmirnov two sample test for independent
samples ( p < 0.05).
The overall effect of patch type on macro-faunal species
richness was assessed by means of a Students t-test for inde-
pendent samples ( p < 0.05). The consistency of the engineer
effect along the exposure and tidal gradient was evaluated
by means of the significance of the interaction term in two
separated two-way analysis of variance (ANOVA). Factors for
the first analysis were Site (fixed, three levels) and Patch
type (fixed, two levels), while Tidal Level (fixed, three levels)
and Patch were used for a second analysis. Further, the effects
of Tidal Level, Patch, and Tidal Level Patch interaction wereevaluated within each Site. Cochrans C-test was used to
check the assumption of homogeneity of variances and,
when necessary, data were log-transformed to remove het-
erogeneous variances. In cases where homogeneity was not
achieved, we set the critical level to a value equal to the
p-value for variance homogeneity (Underwood, 1997). All anal-
yses were done separately for each one the three faunal
groups (total, sessile and mobile species).
Regression analyses were used to evaluate if species rich-
ness was correlated with mussel density and the mean and
standard deviation of mussel shell length and dry weight at
each sampling quadrant. In addition, we examined the corre-
lations between the abundance of mussels and shell traits in
order to remove density-dependent effects on these variables.
In all cases, possible non-linear responses of the independent
variables were investigated by means of the examination of
the significance of the second-order coefficient of a fitted poly-
nomial function. Otherwise, a linear function was adjusted.
Regression analysis was also done separately for total, sessile
and mobile macro-fauna. Log transformed data (both depen-
dent and independent variables) were used for the regression
analysis due to heterocedasticity.
A total of 37 species (or operative taxonomic units) of benthic
invertebrates, distributed in 7 major taxa were found in
the 59 quadrants sampled. These were: 16 crustaceans, 9
molluscs, 3 cnidarians, 4 polychaetes, 2 pycnogoniids, a
nemertean, a ophiuroidean and a platyhelminthe (Table 1).
In addition, three mussel species were present in the assem-
blage: Brachidontes rodriguezii, Perna perna and Mytilus edulis
platensis. Another mytilid, Modiolus carvalhoi, was present as
a single specimen in one quadrant, and considered as a
macro-faunal species. From the analysed samples, 37 were
classified as MEP and 22 as NMEP.
Within the samples more than half of the total sampled
area was engineered (61%), while the maximum Relative Hab-
itat Richness was 1.29. We also found that 10 species were
added to the landscape by the engineer (Landscape Richness
Enhancement, 37%). Generalist species (species present in
the combined engineered and unengineered patches) repre-
sented 67.57% of total species (i.e. Landscape Insurance Poten-
tial). Of these species, 84% showed at least double the
incidence of engineered patches (Habitat Rescue Potential).
Also, 46% of the generalist species showed a mean increase
in abundance from NMEP to MEP, but only 7 species showed
statistically significant differences (Table 1).
Rarefaction curves showed that total species richness
reached the asymptotic maximum after approximately 40
sampling units (Fig. 2) while species richness at MEP did the
same after 27 samples. However, NMEP did not reach an as-
ymptotic value. The total (landscape) curve lay above MEP
and NMEP curves on all the scales, with the latter displaying
the lowest values across the scales. However, there were no
significant differences among the species richness curves, as
shown by the overlapping of the curves 95% confidence inter-
vals (Fig. 2).
Also, at the landscape scale the total species richness was
significantly higher at MEP compared with NMEP (t(1,57) 5.25,p < 0.01). Mussel-engineered patches also showed a signifi-
cantly higher richness of sessile (t(1,57) 3.88, p < 0.01) andmobile (t(1,57) 4.88, p < 0.01) macro-fauna. A significantPatch Site interaction was found for total (ANOVA;F(2,53) 11.255, p < 0.05), sessile (F(2,53) 6.20, p < 0.05) andmobile (F(2,53) 5.04, p < 0.05) species richness, while Level Patch interactions were not significant (Fig. 3).
At the site scale in the protected site, a significant patch ef-
fect was detected for all three faunal groups [total (S), sessile
(SS) and mobile (MS) specific richness], but Tidal Level affected
only sessile (F(2,17) 6.7557, p < 0.05) and total (F(2,17) 4.6116,p < 0.05) macro-fauna. At the Exposed site, the effect of tidal
level was significant for Total (F(2,12) 8.1336, p < 0.05) andmobile species (F(2,12) 4.2866, p < 0.05); no patch effectswere detected. Patch effects within the intermediately ex-
posed site could not be estimated due to insufficient samples.
The richness of total (regression analysis, r2 0.44,p < 0.05), mobile (r2 0.34, p < 0.05) and sessile macro-faunal
a c t a o e c o l o g i c a 3 1 ( 2 0 0 7 ) 2 4 3 2 5 0246
Table 1 Classification of macro-invertebrate species or operative taxonomic units (OTUs) according to their occurrencesand motility
Occurrence Species OTUs Major taxa
G Cymadusa sp. Amphipoda Motile
G Hyale sp. Amphipoda Motile
G Jassa sp. Amphipoda Motile
G Caprella pennantis Amphipoda Motile
MEP Ampithoe sp. Amphipoda Motile
G Ostreola equestris Bivalvia Sessile
G Modiolus carvalhoi Bivalvia Sessile
MEP Sphenia fragilis Bivalvia Sessile
MEP Entodesma patagonicum Bivalvia Sessile
G Actinia bermudensis Cnidaria Sessile
G Actiniaria spp.* Cnidaria Sessile
MEP Bunodosoma cangicum Cnidaria Sessile
G Balanus improvisus* Cyrripedia Sessile
G Chtamalus bisinuatus Cyrripedia Sessile
G Pachycheles haigae Decapoda Motile
G Cyrtograpsus altimanus Decapoda Motile
G Sesarma ? sp. Decapoda Motile
G Pannopeidae indet. Decapoda Motile
MEP Pilumnus reticulatus Decapoda Motile
NMEP Cyrtograpsus angulatus Decapoda Motile
MEP Amphipholis squamata Echinoidermata Motile
G Siphonaria lesonii Gastropoda Sessile
G Lottia subrugosa* Gastropoda Sessile
MEP Costaoanachis sertulariarum Gastropoda Motile
MEP Stramonita haemastoma Gastropoda Motile
NMEP Echinolittorina lineolata Gastropoda Motile
G Idothea baltica Isopoda Motile
MEP Synidothea marplatensis Isopoda Motile
G Lineus rubens* Nemertea Motile
G Alita succinea Polychaeta Motile
G Halodsynella sp.* Polychaeta Motile
G Syllidae indet.* Polychaeta Motile
G Phragmatopoma sp. Polychaeta Sessile
G Pycnogonum pamphorum* Pycnogonida Motile
MEP Anoplodactylus petiolatus Pycnogonida Motile
G Polycladida indet. Plathelminthes Motile
G Tanaidacea indet. Tanaidacea Motile
Occurrence: (MEP) inhabits only engineered patches; (NMEP) inhabits only rocky substrata not engineered by mussels; (G) inhabits both
(generalist). Motility: (1) mobile able to change spatial location; and (2) sessile are attached to primary or secondary substrata (included vagile
species, i.e. with very low mobility). Species with statistically significant differences in abundance (KolmogorovSmirnov two sample test for
independent samples; p < 0.05) between habitat types are denoted with (*).
species (r2 0.33, p < 0.05) were positively correlated withmussel abundance. Sessile macro-faunal specific richness
was positively correlated with the standard deviation of mus-
sel dry weight (r2 0.17; p 0.01). Mean and standard devia-tion of mussel length and weight were not correlated with
Our study demonstrated that at a landscape scale, species
richness is increased by the engineering activity of mussel
species, producing shells that introduce complexity into ben-
thic communities. The positive effect of mussel beds in
macro-faunal species richness did not depend upon site and
tidal level. This increase in species richness at the landscape
scale reflects a significant addition of new species to the
intertidal rocky community that otherwise would remain ex-
cluded. However, this effect seems to be scale-dependent,
since differences in mean richness between MEP and NMEP
within sites were not significant in all cases. The same fact
can be observed in the rarefaction curves, where confidence
intervals overlapped at small spatial scales.
We also found a positive effect on the abundances of 60% of
generalist taxa, which showed higher abundances in mussel
beds than in other patches. The same result has been found
in several studies dealing with the positive effect of mussel
mats, but most are restricted to comparisons between bare
soft sediment and mussel beds (Ragnarsson and Raffaelli,
1999; Commito et al., 2005, 2006). Our results are likely to be
extrapolated to other neighbouring rocky shores with similar
characteristics. In this vein, Cerda and Castilla (2001) reported
that macro-invertebrate diversity did not show differences be-
tween sites at a local scale in Antofagasta Bay (Chile), which
a c t a o e c o l o g i c a 3 1 ( 2 0 0 7 ) 2 4 3 2 5 0 247
suggests that the effect of the exotic engineer Pyura praeputia-
lis on the increase of species richness was similar along the
coast of the bay (Castilla et al., 2004).
The positive effect of mussels supports the suggestion of
Crooks (2002), who stated that engineers that increase habi-
tat complexity tend to favour either the diversity or abun-
dance of organisms. Conversely, engineers that decrease
habitat complexity should have a negative effect on diversity
or abundance. Chapman et al. (2005) showed that most inver-
tebrate taxa, especially the more widespread and numerous
ones, were generally more abundant in turf (coralline algae)
than in mussel beds. However, Commito et al. (2005) reported
a reduction of species diversity in mussel bed patches com-
pared with the unengineered bare sediment, in a situation in
which the engineers increased spatial heterogeneity and
Tokeshi and Romero (1995) have shown that specific
groups of organisms are favoured in mussel beds. For exam-
ple, our results showed that mobile polychaetes are several
times more abundant in mussel beds (ranging from 29 to
>1000) than on unengineered rock surfaces. These species
may be favoured by the structurally complex substrata with
interstitial spaces generated by mussels, thus providing shel-
ter on the otherwise exposed rocky substrate. In addition,
direct and/or indirect trophic interactions account for the
presence of several species in mussel beds. Polyclad flat-
worms, for instance, belong to a group of species known to
predate on oysters (Watanabe and Young, 2006) and are exclu-
sively found on mussel beds, whereas the whelk Stramonita
haemastoma preys on bivalves and on Sabelariid polychaetes
0 5 10 15 20 25 30 35 40 45 50 55CUMULATIVE SAMPLES
Fig. 2 Rarefaction curves for the species pool mean (solid
lines) and its confidence intervals based on the number of
patches sampled: engineered (MEP), total (L) and non-
mussel-engineered (NMEP) patches. The asymptotic curve
indicates that total species richness in landscape was
reached after 40 sampling units. In the cases of the
engineered (small dotted line) and unengineered (large
dotted line) patches the rarefaction curve did not reach an
asymptotic value. All calculations were performed using
the Ecosim program.
(Suchanek, 1978, 1985; Lintas and Seed, 1994). Decapod crusta-
ceans and some amphipods probably require the secondary
space afforded by mussels as a refuge from water movement
and desiccation (Bain, 1991; Piel, 1991; Genzano, 2002). Pycno-
gonids, in turn, are commonly found along with sessile or
sluggish invertebrates that are associated with mussels, in-
cluding sea anemones and hydroids on which they prey
(Genzano, 2002). Strong interactions with mussel associated
species may occur during early phases of the life cycle. For ex-
ample, the endoparasitic larvae of the sea spider A. petiolatus
were reported to be associated with colonies of Bouganvillid
Hydrozoans. In this context, the presence of P. pamphorum
(one occurrence within unengineered patches dominated by
algae Ulva sp.) may be ascribed to dislodgement from neigh-
bouring mussel beds. Mussels also provide secondary
substrata for attachment (L. subrugosa, S. lessonii) and may
enhance the likelihood of settlement of some species (e.g.
the bivalves S. fragilis, M. carvalhoi, E. patagonicum, Balanus
sp.). In addition, Ophiouoideans and polychaetes are able to
colonize the sediment trapped between mussel beds and the
bare rock surface (Prado and Castilla, 2006).
On the other hand, other species or functional groups may
be negatively affected by mussel engineering. The presence of
specialists on patches not engineered by mussels may be in-
dicative of a negative interaction between mussels and these
species. Nevertheless, only one of the species collected (the
crab C. angulatus) was exclusively associated with macro-
algae. Other putative engineering organisms, like the barnacle
Chthamalus bisinuatus, which occur at high densities on the
rocky platform, were associated only with the gastropod Echi-
nolittorina lineolatta and restricted mainly to supra and mesoli-
toral levels (reflecting the species vertical zonation pattern in
response to physical gradients).
Total, sessile and mobile species richness within MEP were
positively correlated with mussel abundance. The positive
correlation between the richness of sessile macro-fauna and
mussel density could be explained because of the expected
relationship between mussel density and substrate area
available. Mobile macro-fauna, in turn, might depend upon
crevices generated between mussels. This suggests that the
patterns in abundance and occurrence of different functional
groups did not respond in the same way to the engineering
effect and that dispersal capabilities and body size might
affect the way in which the organisms interact with their
environments (Collins and Glenn, 1991).
Although other studies have shown that species richness
and diversity of the associated fauna increased with age
and size of mussel patches (Tsuchiya and Nishihira, 1985,
1986), the variables that measured individual shell traits
(i.e. mean shell length and mean dry weight) were not corre-
lated with specific richness. Similarly, variables measuring
heterogeneity in individual shell traits (i.e. length SD and
dry weight SD) were not correlated with patch species rich-
ness, except for the positive correlation between sessile
macro-faunal and dry weight SD. This positive correlation
may reflect a positive response to increasing heterogeneity
in mussel beds. In general, mean and standard deviation of
mussel length as well as mean mussel dry weight were not
useful in explaining variation in species richness. In this
vein, mussel densities and lengthfrequency distributions
a c t a o e c o l o g i c a 3 1 ( 2 0 0 7 ) 2 4 3 2 5 0248
NMEP MEP NMEP
NMEP MEP NMEP
Fig. 3 Variation in mean total (S, ), sessile (SS, -) and mobile (MS, 6) specific richness between engineered andunengineered patches between sites and Tidal Levels. Vertical bars denote 0.95 confidence intervals.
may interact in a complicated fashion. According to Commito
and Rusignuolo (2000), an intermediate percentage cover of
mussels of different sizes would have a highly irregular sur-
face and large values of fractal dimension (i.e. a measure of
habitat complexity), while similar-sized, densely packed
mussels at 100% cover might have a relatively smooth
surface and small values. Thus, if micro-scale habitat
complexity is indeed an important control then maximum
values of specific richness are expected at large values of
fractal dimension. However, recent studies concluded that
habitat heterogeneity may not be an accurate indicator of
faunal diversity (Le Hir and Hily, 2005).
For conservation and management purposes, the identifi-
cation of key processes that maintain mussel-bed structure
a c t a o e c o l o g i c a 3 1 ( 2 0 0 7 ) 2 4 3 2 5 0 249
are of outmost importance, since these structures control the
local richness of benthic species. The mussel beds studied
here are key structures that add species to the landscape
and it is therefore vital that shelled bivalves are not neglected
as conservation targets. Quantitative research on the relation-
ship between different community traits (species richness
and composition, abundance distribution) and environmental
factors (exposure, habitat complexity, energy input, seascape
configuration, pollution) is needed to understand community
structure and to ensure a proper management of protected
We acknowledge financial support from the Maurice Lang
Foundation through the Rufford Small Grants for Nature Con-
servation. We extend our gratitude to J. Gutierrez for his great
help with an earlier version of the manuscript. A.I.B. thanks
the Cleveland Metroparks Zoo for funding received. A.C. ac-
knowledges CSIC and PEDECIBA for financial support. Marina
and Estela are acknowledged for their support. We also thank
our colleagues D. Caliari, P. Muniz, L. Gimenez, M. Sarassola,
M. Arim, V. Korenko, G. Laufer, C.F. Fagundez, and E. Grosso
from Facultad de Ciencias.
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BASES para la CONSERVACINy el MANEJO de la
R. MenafraL. Rodrguez-Gallego
F. ScarabinoD. Conde(editores)
La referencia correcta de este libro es:
Menafra R Rodrguez-Gallego L Scarabino F & D Conde(eds) 2006 Bases para la conservacin y el manejo de la costauruguaya. VIDA SILVESTRE URUGUAY, Montevideo.i-xiv+668pp
Armado y diagramacin: Javier Gonzlez
Fotografa de portada: Faro de Cabo Polonio (Rocha)Diego Velazco - Aguaclara Fotostock,www.aguaclara.com.uy
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LISTA DE AUTORES PARTICIPANTES
Mapa general de la costa platense-atlntica
Mapa de la costa Oeste del Ro de la Plata
Mapa del sector centro-Sur de la costa platense-atlntica
Mapa del sector Este de la costa atlntica
Evolucin paleogeogrfica y dispersin de los sedimentos del Ro de la PlataRICARDO N. AYUP-ZOUAIN
Geologa de la costa uruguaya y sus recursos minerales asociadosCSAR A. GOSO AGUILAR & ROSSANA MUZIO
Dinmica y fuentes de sedimentos de las playas uruguayasDANIEL PANARIO & OFELIA GUTIRREZ
Geomorfologa y procesos erosivos en la costa atlntica uruguayaMARA ALEJANDRA GMEZ PIVEL
Fitoplancton de la zona costera uruguaya: Ro de la Plata y Ocano AtlnticoGRACIELA FERRARI & LETICIA VIDAL
El impacto de las floraciones algales nocivas: origen, dispersin, monitoreo,control y mitigacinSILVIA M. MNDEZ
Flora y vegetacin de la costa platense y atlntica uruguayaEDUARDO ALONSO-PAZ & MARA JULIA BASSAGODA
Fauna parasitaria del lobo fino Arctocephalus australis y del len marino Otariaflavescens (Mammalia, Otariidae) en la costa uruguayaDIANA MORGADES, HELENA KATZ, OSCAR CASTRO, DINORA CAPELLINO, LOURDES CASAS,GUSTAVO BENTEZ, JOS MANUEL VENZAL & ANTONIO MORAA
Zooplancton gelatinoso de la costa uruguayaMARA GABRIELA FAILLA SIQUIER
Zooplancton de ambientes costeros de Uruguay: aadiendo piezas alrompecabezasGUILLERMO CERVETTO, DANILO CALLIARI, LAURA RODRGUEZ-GRAA, GISSELL LACEROT& RAFAEL CASTIGLIONI
Faunstica y taxonoma de invertebrados bentnicos marinos y estuarinos dela costa uruguayaFABRIZIO SCARABINO
Gasterpodos marinos y estuarinos de la costa uruguaya: faunstica,distribucin, taxonoma y conservacinFABRIZIO SCARABINO, JUAN CARLOS ZAFFARONI, ALVAR CARRANZA, CRISTHIAN CLAVIJO& MARIANA NIN
Bivalvos marinos y estuarinos de la costa uruguaya: faunstica, distribucin,taxonoma y conservacinFABRIZIO SCARABINO, JUAN CARLOS ZAFFARONI, CRISTHIAN CLAVIJO, ALVAR CARRANZA& MARIANA NIN
Patrones geogrficos de diversidad bentnica en el litoral rocoso de UruguayALEJANDRO BRAZEIRO, ANA INS BORTHAGARAY & LUIS GIMNEZ
Comunidades bentnicas estuarinas de la costa uruguayaLUS GIMNEZ
Asociaciones de moluscos bentnicos cuaternarios en la costa uruguaya:implicancias paleoecolgicasSERGIO MARTNEZ &ALEJANDRA ROJAS
Los recursos pesqueros de la costa de Uruguay: ambiente, biologa y gestinWALTER NORBIS, LAURA PAESCH & OSCAR GALLI
reas de cra de peces en la costa uruguayaSUSANA RETTA, GUSTAVO MARTNEZ & ADRIANA ERREA
Caractersticas biolgicas de la corvina (Micropogonias furnieri) en el Ro de laPlata y su Frente MartimoERNESTO CHIESA, OSCAR D. PIN & PABLO PUIG
Abundancia, capturas y medidas de manejo del recurso corvina(Micropogonias furnieri) en el Ro de la Plata y Zona Comn de PescaArgentino-Uruguaya (1975-2003)OSCAR D. PIN, GUILLERMO ARENA, ERNESTO CHIESA & PABLO PUIG
Herpetofauna de la costa uruguayaRAL MANEYRO & SANTIAGO CARREIRA
Biologa, ecologa y etologa de las tortugas marinas en la zona costerauruguayaMILAGROS LPEZ-MENDILAHARSU, ANDRS ESTRADES, MARA NOEL CARACCIO,VICTORIA CALVO, MARTN HERNNDEZ & VERNICA QUIRICI
Conservacin y manejo de tortugas marinas en la zona costera uruguayaMARTN LAPORTA, PHILIP MILLER, MARIANA ROS, CECILIA LEZAMA, ANTONIA BAUZ, ANITAAISENBERG, MARA VICTORIA PASTORINO & ALEJANDRO FALLABRINO
Aves de la costa sur y este uruguaya: composicin de especies en los distintosambientes y su estado de conservacinJOAQUN ALDABE, SEBASTIN JIMNEZ & JAVIER LENZI
La franciscana Pontoporia blainvillei (Cetacea, Pontoporiidae) en la costauruguaya: estudios regionales y perspectivas para su conservacinCAROLINA ABUD, CATERINA DIMITRIADIS, PAULA LAPORTA &MARILA LZARO
Revisin preliminar de registros de varamientos de cetceos en la costauruguaya de 1934 a 2005DANIEL DEL BENE, VIRGINIA LITTLE, RICARDO ROSSI & ALFREDO LE BAS