Species–environment sorting explains latitudinal patterns in spatiotemporal β-diversity for freshwater macroinvertebrates

Understanding how and why β-diversity varies along latitude is a long-standing challenge in community ecology and rarely addressed in both space and time. We aimed to explore the spatiotemporal variations in macroinvertebrate β-diversity and their underlying drivers in eight biogeographic regions covering a substantial latitudinal gradient of more than 40 degrees. By combining β-diversity partitioning and distance decay of community similarity analyses, we found that subtropical β-diversity varies more in space relative to variation in time compared with temperate β-diversity, as we predicted. This is probably because subtropical β-diversity is shaped by species–environment sorting (SS), caused by habitat heterogeneity and species specialization, more strongly in space relative to time than temperate β-diversity. Our study highlights the importance of SS in shaping latitudinal gradients of β-diversity in space and time.