Efectos de bioturbación del cangrejo Chasmagnathus granulata sobre el sedimento, los organismos bentónicos y los chorlos migratorios.

BOTTO, FLORENCIA

Reserva de biosfera Mar Chiquita: características físicas, biológicas y ecológicas

Martin

Año: 2001; p. 153 - 160

Thebioturbation effect of the crab Chasmagnathus granulata on the sediment,benthic organisms andmigratoryshorebirds. Abstract: The burrowing crab Chasmagnathus granulata is the mostimportantbioturbatorin he Mar Chiquita coastal lagoon. They inhabit the vegetated area withSpartina densiflorawhereis mainly herbivorous and in the bare intertidal flats where is deposit feeder.In the mudflats, thesecrabsremove important amounts of sediment, redistributing the particles, enhancingwater content andpenetrabilty.However, as the sediment they extract is fine and cohesive, they stabilize thesubstrate. Otherimportanteffect is the increase of organic matter due to the passive deposition of detritusin the burrowswithfunnel shape entrances. Modification of sediment characteristics affects thebenthos, particularlypolychaetes,nematodes and razor clams. Also, evidences show that this species displaces thegrapsid crabCyrtograpsusangulatus from areas suitable for burrowing. On the other hand, the crab bedsindirectlyaffectthe distribution and foraging behavior of shorebirds in the estuary. Therefore,C. granulata is actingasan "ecosystem engineer" changing the physical state of the habitat,controlling the resources (enhancingwatercontent and nutrients) and modulating abiotic (erosion) and biotic (prédation)forces for other species.Consequently,this crab is involved in several interactions with a fundamental role in thefunctioning oftheir environment.