Patrones taxonómicos y ecológicos entre comunidades de peces en rios y arroyos en el oeste de Jalisco, México

Abstract

A MULTIVARIATE, INDIRECT GRADIENT ANALYSIS WAS USED TO ASSESS THE RELATIVE IMPORTANCE OF LARGE-SCALE ZOOGEOGRAPHIC FACTORS AND SITE-SPECIFIC HABITAT FEATURES ON FISH ASSEMBLAGE COMPOSITION IN RIVERS AND STREAMS OF WESTERN JALISCO, MEXICO. COAHUAYANA, MARABASCO, AND PURIFICACIÓN, WERE ANALYZED. A TOTAL OF 25 SPECIES (9 ENDEMIC, 4 EXOTIC) AND 17 GUILDS (4 EXOTIC) WERE ENCOUNTERED, BUT NO SPECIES OR GUILD OCCURRED IN ALL FIVE BASINS. MOST GUILDS WERE REPRESENTED BY ONLY ONE OR TWO SPECIES, SO RESULTS FOR SPECIES AND GUOLD ANALYSES WERE SIMILAR. BASIN WAS THE MOST IMPORTANT VARIABLE IN EXPLAINING VARIATION IN SPECIES AND GUILD COMPOSITION AMONG SITES, WITH FOUR OR FIVE BASINS HAVING UNIQUE SPECIES AND GUILDS. THE FISH ASSEMBLAGES OF THE MARABASCO AND PURIFICACIÓN BASINS WERE GENERALLY ALIKE, BUT THOSE OF THE AMECA, ARMERÍA, AND COAHUAYANA BASINS COULD BE DISTINGUISHED FRON EACH OTHER FROM THE MARABASCO-PURIFICACIÓN BASINS. THE THREE OTHER ZOOGEOGRAPHIC VARIABLES CONSIDERED IN THE ANALYSIS -ELEVATION, DISTANCE TO THE PACIFIC OCEAN, AND WATERSHED AREA- EXPLAINED RELATIVELY LITTLE VARIATION. AFTER BASIN HAD BEEN TAKEN INTO ACCOUNT, THREE HABITAT FEATURES -RIPARIAN VEGETATION, DEPTH, AND COVER- ACCOUNTED FOR SIFNIFICANT AMOUNTS OF THE REMAINING VARIATION AMONG SITES IN SPECIES AND GUILD COMPOSITION. THE FOURTH VARIABLE, SUBSTRATE, HAD LITTLE EXPLANATORY POWER. RIPARIAN VEGETATION WAS THE MOST CONSISTENTLY IMPORTANTA HABITAT FEATURE; SITE WITH EXTENSIVE, WELL-DEVELOPED, NATURAL RIPARIAN VEGETATION TENDED TO HAVE SIGNIFICANTLY DIFFERENT FISH ASSEMBLAGES THAN SITES LACKING NATURAL RIPARIAN VEGETATION.