CS35 Trophic Dynamics
Date: Wednesday, June 12, 2002
Location: Poster Session - VCC
 
JOSÉ ANDRADE JA,  Universidad de Oriente, Departamento de Biología, Cumaná, Venezuela, jantrade@cantv.net
Mazumder, A, , Victoria, Victoria, Canada, mazumder@uvic.ca
 
FOOD WEB INTERACTIONS among INTER-TIDAL invertebrates ON THE NORTH-EASTERN COAST OF VENEZUELA.
image
In the coastal areas, the trophic relationships are very wide and complex. Very little is known about the foodweb relationships among the invertebrate communities of coastal inter-tidal ecosystems, especially of tropical zones. We used the stable isotopes of N and C to characterise the trophic relationships among inter-tidal invertebrates exposed to various environmental and human impacts. This study was conducted on six inter-tidal sites (Garrapata, San Luis, and Guayacán on the western side and Saucedo, Manzanillo and Grande, on the eastern side) along the coast of the Sucre State. Firstly, we characterised the trophic position of major invertebrate taxa and than quantified the trophic relationship between the two dominant taxa of oligochaete and isopod. P. litoralis (oligochaete) and T. wegeneri (isopod) seemed to share similar habitat and food resources. However, under scarcity of food resources and adverse environmental conditions, T. wegeneri may prey on P. litoralis. We used 15N to demonstrate the prey-predator relationships between oligochaete and isopod and to show the diet shift in isopod with size.