Landscape‐scale deforestation decreases gene flow distance of a keystone tropical palm, Euterpe edulis Mart (Arecaceae)

Abstract

Habitat loss represents one of the main threats to tropical forests, which have reached extremely high rates of species extinction. Forest loss negatively impacts biodiversity, affecting ecological (e.g., seed dispersal) and genetic (e.g., genetic diversity and structure) processes. Therefore, understanding how deforestation influences genetic resources is strategic for conservation. Our aim was to empirically evaluate the effects of landscape‐scale forest reduction on the spatial genetic structure and gene flow of Euterpe edulis Mart (Arecaceae), a palm tree considered a keystone resource for many vertebrate species. This study was carried out in nine forest remnants in the Atlantic Forest, northeastern Brazil, located in landscapes within a gradient of forest cover (19–83%). We collected leaves of 246 adults and 271 seedlings and performed genotyping using microsatellite markers. Our results showed that the palm populations had low spatial genetic structure, indicating that forest reduction did not influence this genetic parameter for neither seedlings nor adults. However, forest loss decreased the gene flow distance, which may negatively affect the genetic diversity of future generations by increasing the risk of local extinction of this keystone palm. For efficient strategies of genetic variability conservation and maintenance of gene flow in E. edulis, we recommend the maintenance of landscapes with intermediary to high levels of forest cover, that is, forest cover above 40%.

Exotic Palms Threatens Native Palms: A Risk to Plant Biodiversity of Atlantic Forest

“…Although we did not evaluate how forest fragmentation influences growth and gene flow dynamics of palm trees (Santos et al, 2016), we note that fragmentation probably had direct and indirect effects on plant biodiversity in both study sites. Currently, the Atlantic Forest is heavily fragmented, and evidence shows that species composition responds strongly to the degree of isolation or connectivity, fragment size and shape, as well as characteristics of surrounding matrices and edges (Bierregaard Jr. et al, 1992;Brasil, 2003).…”

“…The continuous increase of A. alexandrae may create a genetic flow barrier among E. edulis populations through mechanisms such as resource competition, as well as differential pollination, seed dispersal, and seedling survival efficiency (Carvalho et al, 2015;Santos et al, 2016). In contrast to A. alexandrae success, we found a low number of L. chinensis seedlings, despite previous reports of high germination rate (96-99%) regardless of soil and climatic conditions (Kobori, 2006).…”

“…Along with fragmentation effects, the invasion of exotic species has led to plant biodiversity big losses in Atlantic Forest remnants (Christianini, 2006). Biodiversity loss begins with reduced environmental and genetic variability (along with any interactions), eventually culminating in local extinction (Santos et al, 2016). Through competitive exclusion, invasive terrestrial plants can profoundly modify the physical and biological characteristics of their surroundings (D'Antonio and Vitousek, 1992), altering soil properties, shading, primary productivity, and susceptibility to fire (Christianini, 2006;Mengardo and Pivello, 2012).…”

“…The status of E. edulis is considered indicative of conservation effort devoted to a given forest fragment. Predatory illegal exploitation (Orlande et al, 1995), coupled with deforestation and fragmentation, devastated natural E. edulis populations and caused a decline in palm-heart production during the 1960s (Cervi, 1996;Carvalho et al, 2015;Santos et al, 2016).…”

Spatial genetic structure, population dynamics, and spatial patterns in the distribution ofOcotea catharinensisfrom southern Brazil: implications for conservation

“…Genetic structure within a population is commonly known as spatial genetic structure (SGS), or fine-scale spatial genetic structure. Studies of SGS and its causes have provided fundamental guidelines for plant conservation and actions, e.g., minimum distances required for seed collections (Tarazi et al 2010), associations between habitat fragmentation and SGS (Santos et al 2016), and estimates of neighborhood sizes (Buzatti et al 2012). By using information D r a f t gained from both demographic and genetic studies, we might be able to propose feasible management and conservation strategies for plant species.…”