Spiders (Arachnida: Araneae) are one of the most diverse and abundant taxa in the Arctic and are affected by fine scale changes in their environment, including temperature, precipitation, and habitat structure. This thesis describes research that occurred across the boreal forest tundra transition zone in the Yukon Territory, Canada. This study system provides an opportunity to test hypotheses about biogeographic patterns and determinants of diversity and life history of spiders in the north. There were four objectives of this research: first, to determine which environmental factors most influence spider assemblage structure (i.e., composition, richness, abundance) at a regional scale in the Arctic; second, to understand patterns [...]