Experimental evidence that intra-specific competition in seagrass meadows reduces reproductive potential in the sea urchin Paracentrotus lividus (Lamarck)


Autoria(s): Tomàs Nash, Fiona; Romero, Javier (Romero Martinengo); Turon Barrera, Xavier
Contribuinte(s)

Universitat de Barcelona

Data(s)

15/10/2012

Resumo

To better understand the biological controls that regulate sea urchin dynamics, we studied the effects of potential inter- and intra-specific competition for food on several biological variables of the main sea urchin in the Mediterranean (Paracentrotus lividus). We carried out a caging experiment in which we manipulated sea urchin density (natural vs. high density) and herbivorous fish (Sarpa salpa) accessibility (free access vs. exclusion) in a Posidonia oceanica meadow. No evidence of competition between fish and urchins was detected. Neither density-dependent mortality nor changes in the somatic variables were found; however, we detected that intra-specific competition affected the reproductive potential of P. lividus. The gonad index of urchins at high population densities was ca. 30% lower than that of urchins at natural densities. As a spawning event had just occurred when urchins were collected, these differences probably reflect differences in reserve content, which may compromise the following reproductive period and decrease survival in the long term, as the gonads are also used as storage organs. For the time period studied, mortality rates appeared to be independent of local densities. The results indicate that a long-term negative feedback mechanism appears to take place in P. lividus in response to increased population density.

Identificador

http://hdl.handle.net/2445/32312

Idioma(s)

eng

Publicador

Consejo Superior de Investigaciones Científicas (CSIC)

Direitos

cc-by-nc (c) Consejo Superior de Investigaciones Científicas (CSIC), 2005

info:eu-repo/semantics/openAccess

<a href="http://creativecommons.org/licenses/by-nc/3.0/es">http://creativecommons.org/licenses/by-nc/3.0/es</a>

Palavras-Chave #Fanerògames #Ecologia marina #Eriçons de mar #Posidònia #Phanerogams #Marine ecology #Sea urchins #Posidonia
Tipo

info:eu-repo/semantics/article

info:eu-repo/semantics/publishedVersion