Arañas de humedales del sur de Baja California, México

Abstract

DURING THE AUTUMNS OF 1994 TO 1996, 355 ADULT SPECIMENS BELONGING TO 61 SPECIES OF SPIDERS WERE COLLECTED FROM FIVE WETLANDS AND ONE INTERMITTENT SPRING IN SOUTHERN BAJA CALIFORNIA. WANDERING SPIDERS WERE DOMINANT, WITH 36 SPECIES AND 63% OF TOTAL ABUNDANCE. DIFFERENCES IN FLORISTIC RICHNESS BETWEEN SITES ALSO WERE RELATED TO VARIATIONS IN THE ARACHNOFAUNA. MISUMENOPS DUBIUS, HIBANA INCURSA, AND THERIDION SP. WERE MORE ABUNDANT, AND WITH THE EXCEPTION OF THE LAST SPECIES, THEY ARE ALSO MORE COMMON IN ASSOCIATION WITH DICTYNA SP. AND THIODINA SYLVANA, WHICH WERE LESS ABUNDANT. THE OASIS OF SAN IGNACIO AND THE SPRING AT SAN BARTOLO WERE THE SITES WITH MOST SPECIES RICHNESS AND HETEROGENEITY, WITH SPECIFIC DIVERSITY OF 3.22 AND 2.63, RESPECTIVELY. ABOUT 59% OF THE SPECIES WERE EXCLUSIVE IN EACH LOCALITY AND THE MEAN SIMILARITY BETWEEN THEM WAS 0.27; 0.53 SIMILARITY BETWEEN BOCA DE LA SIERRA POOLS AND SAN BARTOLO SPRING, AND 0.46 BETWEEN SAN BARTOLO SPRING AND THE INTERMITTENT SAN JUAN BAUTISTA SPRING. INTENSIVE AND SEASONAL SAMPLINGS, AND MORE EFFECTIVE COLLECTING METHODS COULD PROVIDE MORE ACCURATE CHARACTERISTICS OF THE ARACHNOFAUNA IN THE SOUTHERN PART OF THE PENINSULA.