Genetic diversity and fragmentation of Aspidosperma quebracho-blanco (Apocynaceae) natural habitats, conservation issues in Chaco forest and savanna biomes

Abstract

The present study analyses the first data on genetic diversity of A. quebracho-blanco with the fragmentation of its natural habitat, supporting conservation strategies such as the definition of priority areas for conservation. DNA was extracted from 25 individuals of five populations of A. quebracho-blanco from Argentina, Paraguay, and Brazil. Six ISSR primers were used to characterize the genetic diversity and structure of this species. The genotypes were grouped according to a distance matrix, considering the genetic diversity indices of Nei (He), Shannon (H’), polymorphic information content (PIC), and heterozygosis (H). The populations showed an average genetic diversity that ranged from 0.09 to 0.15 for the Shannon index and from 0.19 to 0.31 for the Nei index; the Mantel test was not significant (r2 = 0.25, P = 0.106). The results obteined for the sampled populations reveal that conservation units are indispensable for conserving the species genetic resources. In addition, it would be essential to construct a germplasm bank for the Cordoba (Argentina) population, which is a population with high genetic diversity in a region of lower fragmentation compared to other regions evaluated, to ensure the conservation of A. quebracho-blanco.

Diversity of ground‐dwelling ants across three severely threatened South American subtropical forests: are diversity patterns influenced by spatial or climatic variables?

“…This species is considered as a disturbed habitat indicator because it is strongly associated with fragmented dry tropical forest edges in Brazil and Colombia (Majer & Delabie, 1999; Achury et al ., 2008, 2012) and disturbed habitats both within its native and introduced range (Foucaud et al ., 2009; Orivel et al ., 2009; Chifflet et al ., 2018). This suggests that fragmentation of the Chaco forest could have favoured the dominance of invasive species in this biome, or, in other words, that the abundance of invasive ant species (as indicator species) reflects the high level of degradation of this forest (Schmidt, 2015; Botelho et al ., 2021). Wasmannia auropunctata was also one of the most common species in human‐modified tropical rainforest landscapes in eastern Mexico, suggesting that the long‐term modification of the forests could cause the replacement from specialist to generalist leaf litter species making them more vulnerable to colonisation by cosmopolitan ‘tramp’ ants (i.e., species dispersed by human activity and associated to human‐disturbed habitats (Ahuatzin et al ., 2019).…”