Recently Naturalized Paraserianthes lophantha subsp. lophantha Displays Contrasting Genetic Diversity and Climate Relationships Compared to Native Populations

Gillian K Brown,Collin W Ahrens,Catherine L Simmons,Elizabeth A James

doi:10.3390/d12110422

Gillian K Brown, Collin W Ahrens + Show 2 more

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https://doi.org/10.3390/d12110422

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Abstract

Paraseriantheslophantha subsp. lophantha (Leguminosae) is native to southwestern Australia, but has become naturalized in eastern Australia and in countries around the world. Previous studies have investigated the introduction sources for P. lophantha subsp. lophantha overseas, but here, we expand on the knowledge of genetic patterns in its native and naturalized range in Australia. Genetic patterns were examined using nine nuclear microsatellite loci and three chloroplast DNA markers. The native populations exhibited phylogeographic patterns, including north-south differentiation, and a genetic signal related to temperature gradients. Naturalized Australian populations displayed lower overall genetic variation and no phylogeographic patterns. Several naturalized populations separated by large distances (350–650 km) shared multi-locus genotypes, supporting the notion of a shared source of germplasm and possible inbreeding due to human-mediated introductions from a limited number of individuals and/or source populations within the native range. We advocate that management strategies are tailored to the distinct conservation aims underpinning conservation in native or naturalized populations. Within the native distribution, management should have a long-term aim to replicate historical evolutionary processes, whereas in naturalized populations, immediate actions may be required to reduce the abundance of P. lophantha subsp. lophantha and minimize its invasive impact on the recipient vegetation.

Highlights

The evolutionary history of a species is determined by the spatially and temporally variable environments they experience [1,2,3]
This study reports on differences found in the genetic signal and relationships between climate native populations that overlap with the naturalized populations (CA and RC; to the right of the variables of Australian P. lophantha for native and naturalized regions and significant isolation-bycenter line) are the most easterly native populations and are located at least 500 km from the distance (IBD) within the native region, but not the naturalized region
Differences (BIO12, p = 0.017, r2 = 0.61), maximum temperature of the warmest month (BIO5, p = 0.001, r2 = 0.32), between regions are consistent with generally limited dispersal restricting gene flow in native and isothermality (BIO3, p = 0.097, r2 = 0.20)

Summary

Introduction

The evolutionary history of a species is determined by the spatially and temporally variable environments they experience [1,2,3]. The natural evolutionary trajectory of a species begins with range expansion determined by the ability to disperse to new habitats, and intrinsic genetic factors that allow adaptation to novel environments [6,8,9]. The human-mediated dispersal of endemic species beyond their native range, but within their country-of-origin, may create a considerable risk for native biodiversity [13] and is an emerging management issue in Australia [14]. Human-mediated dispersal beyond a species’ natural capability has been the major factor underlying the establishment of plant species outside their native ranges, and their rapid spread effectively increases contemporary gene flow and global homogenization [15]. The anthropogenic alteration of habitats has enabled native species to expand their ranges into new environments [18]. Webber et al [19]

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