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Accueil du site → Doctorat → Mexique → Cambios en la estructura de la comunidad íctica en tres sistemas de manglar áridos del Golfo de California : 1980-81 versus 2009-10

Centro de Investigaciones Biológicas del Noroeste (CIBNOR) 2013

Cambios en la estructura de la comunidad íctica en tres sistemas de manglar áridos del Golfo de California : 1980-81 versus 2009-10

López Rasgado, Francisco Javier

Titre : Cambios en la estructura de la comunidad íctica en tres sistemas de manglar áridos del Golfo de California : 1980-81 versus 2009-10

Auteur : López Rasgado, Francisco Javier

Etablissement de soutenance : Centro de Investigaciones Biológicas del Noroeste (CIBNOR)

Grade : Doctorado en Ciencias en el Uso, Manejo y Preservación de los Recursos Naturales 2013

Résumé
Mangrove systems are of great importance worldwide for their high primary and secondary productivity because they sustain fish abundance and diversity. The aim of this study was to compare the current structure and composition (2009-2010) of the fish community in three mangrove systems with different degrees of anthropogenic influence in the Bay of La Paz, Baja California Sur, with estimates made 30 year ago (1980-1981) for each system to establish a structure and function baseline of the fish community. Ecological attributes were estimated (number and weight density, species richness, Shannon-Wiener diversity, Pielou evenness), and average taxonomic distinctness (ATD) from data collected monthly during each period. To characterize the function of the mangrove systems an isotopic analysis was performed on the fish caught during sampling from 2009-2010. A total of 39,123 fish were recorded in 1980-1981 and 16,740 fish in 2009-2010. During both periods, the species that dominated the density in the three systems were Eucinostomus dowii, Diapterus brevirostris, and Mugil curema. Enfermería exhibited the most drastic changes in fish community structure between periods, where species richness, equity, and diversity decreased significantly ; some DTP values indicated the dominant species were closely related, coinciding with the current deterioration of intense undergoing anthropogenic impact. Zacatecas showed light significant changes in richness and weight density between periods. Balandra showed only changes in weight density between periods. The MDS and ANOSIM analyses revealed differences in fish community structure between periods for Balandra and Enfermeria, although these differences were mainly due to the composition of the species considered rare. Based on the isotopic values of 13C and 15N of the fish muscles, the three mangrove forests do not provide carbon in the food chain of the fish community. The values of 13C and 15N of the fish muscles in Balandra and Zacatecas showed that marine phytoplankton was possibly the basis of the food chain due to the ocean influence in which they are subjected to. While in the Enfermería mangrove, the main food source may come from benthic remineralization. Based on ecological attributes, size frequency, and the stable isotope analysis, the main function of the mangrove forests assessed is protection from predators. Long-term studies are important for understanding the changes in fish community structure that are caused by habitat alteration in the mangrove systems

Mots Clés : diversidad ; Bahía de La Paz ; estructura íctica ; manglar ; isotopos estables

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Page publiée le 28 septembre 2017