Integrating long-term demography and population genetics reveals the persistence of a threatened palm in fragmented Atlantic Forest landscapes

Abstract

Anthropogenic disturbances are a major cause of extinction and population decline, especially in small, unprotected forest fragments where demographic and genetic challenges are more pronounced. Euterpe edulis , a key resource palm species in the Atlantic Forest, plays a crucial ecological role by providing food resources during periods of scarcity. However, the species is threatened by illegal harvesting and habitat degradation. Small forest fragments are often overlooked in conservation strategies but may play an important role in sustaining threatened species. In this context, understanding the demography and genetic diversity of isolated E. edulis populations is essential to inform management and conservation actions. This study investigated the dynamics of three E. edulis populations in small forest fragments over an unprecedented long-time data collecting of 15-year period. Besides we assessed their current genetic diversity based on a single sampling conducted in 2021. The stochastic population growth rate (λs) was analyzed to assess population persistence. Although the adult density is below the viability threshold, the λs indicated a demographic trend very close to stability, ranging from a 1% increase to a 4% decrease. Elasticity analysis revealed that the survival and growth of large individuals were key drivers of λ. The populations, even small, exhibited high genetic diversity and low, non-significant inbreeding coefficients, with genetic structuring observed within the adult stage. These results highlight the critical role of small forest fragments in the conservation of E. edulis and emphasize the need to preserve large individuals to ensure the survival of E. edulis in fragmented landscapes.