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

G. bogotensis has a geographic distribution restricted to the Colombian Cundiboyacense
plateau, it is listed as near threatened, and research on its autoecology is scarce. Three
collections 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 to
determine its vertical and horizontal distribution. Three sampling zones were selected
according to the type of dominant macrophyte (Eichornia crassipes, Schoenoplectus
sp. 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. Three
replicates were used for each depth and type of trap. Traps were exposed for 24 hours
and checked every 6 hours. In addition to the traps, sampling by electrofishing was
conducted 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. Results
showed spatial differences on G. bogotensis habitat occupation and differences in
captures at each depth, which depend on the dominant type of aquatic vegetation
and size of individual. We conclude that only cylindrical cloth traps are suitable to
conduct population studies of G. bogotensis