Effects of aquatic vegetation on the spatial distribution of grundulus bogotensis, humboldt 1821 (characiformes: characidae)

Abstract

G. bogotensis has a geographic distribution restricted to the Colombian Cundiboyacenseplateau, it is listed as near threatened, and research on its autoecology is scarce. Threecollections were made in 2006 in the Fúquene Lake, Cundinamarca, Colombia (5°27’ 55’’ N, 75° 46’ 19’’ W) to describe the habitats occupied by G. bogotensis and todetermine its vertical and horizontal distribution. Three sampling zones were selectedaccording to the type of dominant macrophyte (Eichornia crassipes, Schoenoplectussp. and Egeria densa). In each sampling zone two different cylindrical sampling traps(cloth and PVC) were placed at three depths: surface, mid-depth and bottom. Threereplicates were used for each depth and type of trap. Traps were exposed for 24 hoursand checked every 6 hours. In addition to the traps, sampling by electrofishing wasconducted in each sampling zone during every month. To characterize the study area,physical and chemical variables were analyzed and the structure of phytoplankton,zooplankton, periphyton, and macroinvertebrate communities was studied. Resultsshowed spatial differences on G. bogotensis habitat occupation and differences incaptures at each depth, which depend on the dominant type of aquatic vegetationand size of individual. We conclude that only cylindrical cloth traps are suitable toconduct population studies of G. bogotensi