Genetic diversity and structure of the tree Enterolobium contortisiliquum (Fabaceae) associated with remnants of a seasonally dry tropical forest

Abstract

a b s t r a c tFragmentation of tropical forests is one of the major threats to biodiversity and viable natural populations. Brazilian seasonally dry tropical forests (SDTF) are endangered because of human occupation, conversion of lands to agriculture and high deforestation rates in these fertile soils. Enterolobium contortisiliquum has been removed from SDTF natural areas due to the advance of cattle grazing and agriculture in Brazilian SDTFs. To aid conservation efforts of this species we used molecular markers to study the genetic diversity and population structure of E. contortisiliquum in Brazilian SDTF remnants. A total of 263 individuals in 13 forest patches were analyzed with 103 ISSR fragments. In spite of being found scattered among the SDTF patches, E. contortisiliquum populations exhibited high genetic diversity (mean Shannon's index of diversity = 0.384; mean genetic diversity = 0.280) and genetic divergence between populations was detected (˚S T = 0.155, p < 0.0001). UPGMA dendrogram, principal coordinate analysis and Bayesian analysis showed that E. contortisiliquum populations were clustered into three groups that were not related to geographic distance (r = 0.119, p = 0.197). However, these populations are spatially structured into groups distributed in the West, Central and East of the study area. This genetic structure may be related with landscape and both the Espinhaç o Range and São Francisco River may act as a partial geographic barrier limiting the gene flow. Because the highest rates of genetic diversity were found outside of conservation units, we propose the creation of protected areas in different geographic regions that include E. contortisiliquum populations from different genetic clusters.

Genetic diversity of Enterolobium cyclocarpum in Colombian seasonally dry tropical forest: implications for conservation and restoration

“…In degraded landscapes one would expect to see footprints in the genetic profiles of remaining E. cyclocarpum populations as a result of multiple effects, such as domestic animal and human-mediated seed movement, habitat fragmentation and isolation of trees in pastures leading to a reduction in effective population sizes, among other impacts (Gonzales et al 2010). Fragmentation is known to negatively affect the reproduction, gene flow and genetic diversity of tree populations (Lowe et al 2005;Aguilar et al 2006Aguilar et al , 2008de Abreu et al 2015). Fragmentation may also shift mating patterns towards selfing, both of which, in combination with reduced effective population sizes, may increase the levels of inbreeding, with potentially detrimental effects on the vigor and viability of next generation populations (Rocha and Aguilar 2001;Aguilar et al 2008).…”

The genetic diversity and reproductive dynamics of sandalwood in Gunung Sewu (Java, Indonesia) in 2012-2019: designing conservation strategies in a continuous versus fragmented landrace

“…The continuous fragmentation of tropical forests is considered a main threat to biodiversity conservation (Moreira et al 2015). Habitat fragmentation directly results in three main consequences for plant populations: (i) habitat loss, (ii) population size reduction, and (iii) increased spatial isolation between remnant populations (Klank et al 2012).…”

“…Habitat fragmentation directly results in three main consequences for plant populations: (i) habitat loss, (ii) population size reduction, and (iii) increased spatial isolation between remnant populations (Klank et al 2012). In turn, forest fragmentation may negatively affect gene flow, reproduction, and genetic diversity (Moreira et al 2015). Gene flow through pollen and seeds may be inhibited, inbreeding rates may increase, and the level of isolation in fragmented populations may be exacerbated.…”

“…Habitat fragmentation may result in bottleneck effects because the remnant parents experience a narrow genetic base. Compared with that in continuous populations, the effect of genetic selection is more apparent in disjunct ones (Garfì et al 2013;Moreira et al 2015) because the enhanced bottleneck effect and genetic drift could result in the loss of more alleles (Bottin et al 2007). Thus, reductions in genetic diversity may be attributed to increased isolation, reductions in population size, and alterations in the mating system favoring inbreeding (Young et al 2000).…”

Irrigation Regimes on Growth and Metabolic Processes of Enterolobium contortisiliquum Seedlings

“…It is a tree native to South America found in Brazil, Argentina, Paraguay, and Uruguay (Burkart, 1967). This species can occur in several forest formations; however, it is more commonly found in subtropical forests (Moreira et al, 2015). This species is important for different sectors of the economy, such as timber, shipbuilding, and civil construction (Zuchiwschi et al, 2010).…”