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.