Spider Diversity Across Desert and Coastal Habitats: Rainfall-Related Changes in Northwestern Baja California, Mexico

Rainfall pulses associated with El Niño can influence vegetation, soil moisture, and prey availability in arid ecosystems, potentially altering spider activity and community composition. However, spider diversity and habitat associations remain insufficiently documented across many terrestrial environments in northwestern Baja California, Mexico.

This project will investigate spider communities in three proposed conservation areas: Valle Tranquilo, near El Rosario, and Punta Mazo and Monte Ceniza, in the San Quintín region. The study will document spider diversity across contrasting terrestrial habitats, including runoff channels, upland scrub, and coastal dunes where present and accessible. It will also examine differences in spider communities before and after significant rainfall.

Fieldwork will include two sampling campaigns at each site, two days in each of the study sites. Standardized daytime and nighttime visual searches will be complemented by pitfall traps to document spider richness, observed abundance, taxonomic composition, and habitat associations. Environmental variables, including vegetation cover, substrate, surface moisture, and evidence of runoff, will be recorded alongside precipitation data from weather stations, satellite estimates, and portable rain gauges.

Although two sampling periods cannot fully distinguish rainfall effects from seasonal variation, this project will establish a baseline of spider diversity and habitat associations across the study areas. It will also implement a standardized, replicable monitoring protocol designed for annual repetition. Over the long term, these efforts will provide a foundation for evaluating how rainfall variability influences spider community composition and diversity in arid ecosystems. The resulting data will support future comparisons across climatic conditions, help identify habitats of conservation interest, and contribute to regional biodiversity knowledge. Training and outreach activities will further promote the ecological importance of spiders and encourage the continued participation of conservation staff and local communities in biodiversity monitoring.