Comparative patterns in taxonomic and functional spider diversities between tropical vs. temperate forests

Area of Science:

• Ecology
• Biodiversity Science
• Zoology

Background:

• Tropical regions exhibit higher biodiversity than temperate ones, particularly for arthropods.
• Previous research highlighted arthropod herbivores as key drivers of tropical diversity.
• Quantifying differences in predatory arthropod diversity between tropical and temperate forests remains understudied.

Purpose of the Study:

• To conduct the first standardized comparison of spider diversity between tropical and temperate forests.
• To quantify differences in species richness, evenness, and functional diversity of spiders.
• To assess if tropical-temperate diversity ratios for predatory arthropods exceed those for herbivores.

Main Methods:

• Standardized sampling of spider assemblages using vegetation sweep netting and beating.
• Spatially replicated fieldwork conducted in French Guiana (tropical) and Brittany (temperate).
• Data collected between 2010 and 2015.

Main Results:

• Species richness was 13-82 times higher in tropical forests compared to temperate forests.
• Evenness was also significantly higher in tropical forests, up to 55 times greater.
• No significant difference in functional diversity (hunting guilds) was observed between the two forest types.

Conclusions:

• Tropical forests exhibit dramatically higher spider species richness and evenness than temperate forests.
• These diversity differences surpass previous estimates for both predatory and herbivorous taxa.
• Spiders represent a critical, mega-diverse group for understanding tropical-temperate ecological disparities.