Understanding factors that influence ecological stability is a key question in ecology. Population ecology has highlighted that synchrony within a species across locations is an important indicator of species stability. Community ecology, in contrast, has highlighted that asynchrony between species within a location may enhance the stability of aggregate properties (such as total productivity). We compiled LTER and other data across 20 metacommunities in grassland and coastal marine biomes to integrate population and community approaches to synchrony to understand drivers of ecosystem stability at different scales. All datasets feature long-term (10-34 years) measurements of the primary producer community across multiple (6-49) discrete plots, with taxonomic identifications to species in most or all cases. This data package contains data from coastal marine sites: Santa Barbara Coastal LTER; Moorea Coral Reef; US Virgin Islands; Maui, Hawaii; and the Florida Keys. The data package containing grassland sites is located at [TO DO].