1 | Introduction
Palms (Arecaceae) were among the first plant groups to receive attention regarding the risks of becoming endangered (Moore, 1979), but despite this early attention, many palm species are heading toward population collapse (Moore, 1979). Today, the IUCN Red List of Threatened Species includes about 31% of the world’s 1.150 palm species.
The interest in palm conservation is due to both their economic (Henderson et al., 1995; Zambrana et al., 2007) and ecological importance (Kinnaird, 1992; Terborgh, 1986). Palms have been regarded as a ‘keystone resource species’ (Kinnaird, 1992; Terborgh, 1986) since their disappearance may have a cascading effect on natural ecosystems, changing the competitive relationships and the relative abundance of other species in the community (Howe & Westley, 1988; Polis et al., 2000). Montúfar et al. (2011) have pointed palms as ideal candidates to examine resilience at the species level in ecosystems due to the keystone properties of their populations as they are essential components of forests that may deeply influence the structure and functioning of ecosystems (Aguiar & Tabarelli, 2010; Fadini et al., 2009; Fleury & Galetti, 2006; Fleury et al., 2014; Galetti & Sazima, 2006; Galetti et al., 2006; Peters et al., 2004: Scariot, 1999; Svenning et al., 2008; Wang & Augspurger, 2004; Wright & Duber, 2001). From a socioeconomic perspective, palms are considered a prime Non-Timber Forest Product (NTFP) resource (Henderson et al., 1995), as its fruits, leaves, stems, seeds, sap and other parts are exploited, destructively or not, for numerous purposes by people (Cayuela et al., 2006; Macía, 2004; Zuidema et al., 2007).
The coastal sclerophyllous forest, located at the Chilean Mediterranean biome on Central Chile (31º52’S - 37º20’S) is a diverse ecosystem with high levels of endemism (Luebert & Pliscoff, 2006; Moreno-Chacón et al., 2018; Villagrán, 1995). The palmar, or palm forest, is an overlooked component of the sclerophyllous forest, composed by sclerophyllous forest with numerically abundant populations of the long-lived Jubaea chilensis (Molina) Baill., the Chilean palm, a tertiary-relict endemic species (Zuloaga et al., 2008). The rainforest contractions in Central Chile during the late Pleistocene and the extensive use of Chilean palm, allied to the intense human activity for land change uses in Central Chile, have reduced the pre-Columbian populations of J. chilensis to 2.5% (González et al., 2009, 2017). More recently, such changes are mostly driven by habitat loss and fragmentation, xylem sap extraction from decapitated palm trees, illegal seed overharvesting for human consumption and recurrent wildfires. All these synergic disturbances are therefore expected to have detrimental consequences on the J. chilensis genetic diversity (Aguilar et al., 2008).
Genetic diversity is an essential condition for species persistence through species adaptation, evolution and survival (Rajora & Pluhar, 2003), especially under rapidly anthropogenic changing environment. The palm’s habitat loss and degradation, unsustainable use, spatial isolation, global climate change, and linked consequential reduction of population numbers may all result in genetic drift, inbreeding, hampered gene flow and founder effect, which inevitably put tree species at the edges of extinction vortex (Fageria & Rajora, 2013).
Here, we evaluated the patterns of genetic diversity and population differentiation among natural populations of J. chilensisin Central Chile. We predicted that remaining tree stands of J. chilensis populations have low levels of genetic diversity as a consequences of isolation and low population size. The results of the study will guide for conservation plans and sustainable management strategies for the conservation of this emblematic species and will also guide for conservation plans and sustainable management strategies for the conservation of this emblematic species.