LAUSR

Societal processes of rural change and globalization may change homegardens and their contribution to the conservation of agrobiodiversity, particularly of species occurring naturally in regional vegetation. The best way to determine if this occurs is through longitudinal studies. We conducted such a study, inventorying tree species in a sample of 38 homegardens in 2009, 2012 and 2015. The homegardens were located in the subregions of mountain slopes, fluvial plains and coastal plains in the tropical lowlands of Tabasco, Mexico. We analysed changes in species richness by geographic origin, species richness and species composition in each inventory. We identified 169 tree species in the three inventories, of which 74.6% were native or neotropical and 25.4% introduced. Of the 140 species recorded in 2009, 88% remained in 2015, whereas 12% had been replaced and nine additional species had arrived. Mean species richness increased between 2009 and 2015 (P = 0.03) and between 2012 and 2015 (P = 0.001). Increases resulted from increased mean neotropical (P = 0.01) and introduced (P = 0.01) species richness, and constant native species richness. Differences in species composition between the three subregions in 2009 persisted in 2012 and 2015 (P < 0.001 in all years). These results show how the highly dynamic character of homegardens combines with the renewal and persistence of their agrobiodiversity, and underpins the continued relevance of homegarden for agrobiodiversity conservation and livelihoods in tropical lowlands amidst rural change and globalization.