Multi-decadal changes in two co-occurring ophiuroid populations

Type Article
Date 2012
Language English
Author(s) Blanchet Aline1, Dubois StanislasORCID1, Hily Christian2, Rochette SebastienORCID3, Le Goaster Edouard1, 2, Guillou Monique2
Affiliation(s) 1 : IFREMER, Lab Ecol Benth, Dept Oceanog & Dynam Ecosyst, Ctr Bretagne, F-29280 Plouzane, France.
2 : Univ Bretagne Occidentale, Inst Univ Europeen Mer, LEMAR UMR CNRS IRD 6539, F-29280 Plouzane, France.
3 : IFREMER, Lab Applicat Geomat, Dept Oceanog & Dynam Ecosyst, Ctr Bretagne, F-29280 Plouzane, France.
Source Marine Ecology-progress Series (0171-8630) (Inter-research), 2012 , Vol. 460 , P. 79-90
DOI 10.3354/meps09784
WOS© Times Cited 3
Keyword(s) Echinoderm, Ophiocomina nigra, Ophiothrix fragilis, Food supply, Kriging method, Suspension-feeder
Abstract Mixed beds of Ophiocomina nigra and Ophiothrix fragilis (Echinodermata, Ophiuroidea) are usually predominated by O. fragilis and are reported to be stable over time. The Bay of Brest (Brittany, France) is a highly productive ecosystem where both species co-occur in the main central part. Using a geostatistical approach, we tested for changes in O. nigra and O. fragilis density and total biomass patterns between 1987 and 2011. Our results highlighted an increase in O. nigra population size and the induction of a spatial shift of the co-occurring O. fragilis. O. nigra increased similar to 5 times in density and covered almost all the study area, while its density-dependent biomass increased similar to 3 times (22 t km(-2), ash-free dry mass) between 1987 and 2011. Overall, the O. fragilis population decreased in density by similar to 30%, but its total biomass did not change over time. The current distribution pattern revealed a clear spatial exclusion of O. fragilis from the central part of the study area toward the southern part, overlapping beds of dead slipper limpet Crepidula fornicata, which were formerly considered to be the dominant suspension-feeder species in the bay. The success of O. nigra colonization is linked to its biological and functional traits, as well as deep changes in food supply over the studied period. Ecological consequences of such a large change in the benthic compartment of the bay are explored in the light of associated changes in environmental patterns.
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