Genus replacement and weak spatial structure characterize phytoplankton beta diversity in rain-fed dryland waterpans of Kenya

Across seven campaigns in 12 rain-fed dryland waterpans in Kenya, dry-season phytoplankton beta diversity was higher, driven mainly by soluble reactive phosphorus and balanced genus replacement (~90%).

• Why it matters: Single metacommunity surveys can miss whether beta-diversity correlates persist when hydrological seasonality reorganizes habitat and environmental conditions.
• What they did: Net phytoplankton beta diversity was analyzed across seven campaigns using beta diversity partitioning, permutation tests, variation partitioning, and generalized dissimilarity modelling, relating it to season and land use.
• The result: The wet–dry contrast was not supported when whole campaigns were permuted (p = 0.229), but dissimilarity increased in the dry season; land use showed no effect on composition, and cyanobacteria contributed 41.6% of dry-season beta diversity.