Behavioural responses of the mangrove fiddler crabs (Uca annulipes and U. inversa) to urban sewage loadings: results of a mesocosm approach.
The study aimed at investigating the effects of sewage loadings on the behaviour of two fiddler crabs species maintained in a system of experimental mesocosms, built in a mangrove area in Tanzania and inundated with different seawater/sewage mixtures. Our results show that sewage loads led to a modification of the overall activity budget of the crab community as a result of increased hypertrophic conditions (high COD, increased chlorophyll-a concentrations). During their activity period, crabs inside contaminated mesocosms seemed to satisfy their feeding demand faster than those of the control cells, spending a significant longer time in other activities like courtship and territorial defence. Apart from being a good biological indication of ecosystem eutrophication, such a reduced foraging activity by fiddler crabs also depresses their sediment bioturbation activity, important factor for the health of mangrove systems, suggesting practical implications regarding the efficiency of mangrove-based wetlands for treatment of domestic sewage.
Bartolini
Fabrizio
F
Dipartimento di Biologia Evoluzionistica Leo Pardi, University of Florence, Italy. fabrizio.bartolini@unifi.it
Penha-Lopes
Gil
G
Limbu
Samwel
S
Paula
José
J
Cannicci
Stefano
S
D000818:Animals; D032407:Avicennia / Q000378:metabolism; D001522:Behavior, Animal / Q000187:drug effects*; D003386:Brachyura / Q000187:drug effects*; D002735:Chlorophyllides / Q000032:analysis; D002947:Cities; D017753:Ecosystem; D004784:Environmental Monitoring; D043982:Rhizophoraceae / Q000378:metabolism; D012623:Seawater / Q000737:chemistry*; D012722:Sewage / Q000032:analysis*; D014873:Water Pollutants / Q000032:analysis / Q000633:toxicity*
D002735:Chlorophyllides; D012722:Sewage; D014873:Water Pollutants; C034388:chlorophyllide a