Consequences of land use changes on seed fate and demography in the palm tree Syagrus coronata (Mart.) Becc. (Arecaceae)

Abstract

Palm trees provide several non-timber forest products in the tropics and are commonly found in human-modified habitats. Land use and cover changes have impacted habitat climatic conditions, biodiversity, and the recruitment and survival of palm species. The objective of this study was to evaluate the seed fate and demographic structure of Syagrus coronata (Mart.) Becc. (Arecaceae) in natural (old-growth vegetation) and managed habitats (pastures for cattle ranching). This palm is widely found in Brazilian semi-arid regions, and there is no information on the impacts caused by fruit harvest, management practices and land use on the persistence of this species’ population. We evaluated seed fate for two years, in which 400 ripe post-dispersal fruits were buried and evaluated after 10, 20, 40, 80, 160 and 240 days. We also established 20 plots (20 × 20 m), 30 m apart, in each habitat to obtain data on population demography. In general, greater seed mortality was found in the managed habitat, mostly as a result of desiccation. We found 2,090 S. coronata individuals in the natural habitat with seedling dominance, while only 45 individuals were found in the managed habitat with reproductive adult dominance. Human-modified habitats, like pastures, negatively affected seed survival and, consequently, plant recruitment. The future of this species is alarming given their current fruit harvesting levels, land cover change, and that climate changes predict desertification in the semi-arid region, making it even more difficult seed germination. The social and economic importance of this species reinforces the need for increasing biodiversity-friendly farming practices.