Microsatellite primers for vulnerable and thriving Acacia (Fabaceae) species from Australia’s arid zone1

Ap Applicati tions ons in in Pl Plant t Scien Sciences ces Several Australian arid-zone acacias are threatened by habitat loss, degradation, and fragmentation resulting from agricultural activities and exotic herbivores (Morton et al., 1995), although others, including Acacia ligulata A. Cunn. ex Benth., are thriving. Two long-lived and potentially clonal species facing a variety of potential threats are A. melvillei Pedley and A. pendula A. Cunn. ex G. Don. Both of these latter species likely suffer from infrequent seed production and chronic recruitment failure (Batty and Parsons, 1992). Moreover, there is some debate about the origin and taxonomy of stands of A. pen-dula found in the Hunter region of New South Wales (Bell et al., 2007), the extreme eastern range edge of its distribution and a notable anomaly for this species, given its predominate semi-arid/arid distribution in four Australian states. A clear understanding of the factors underlying the variation in the performance of these three species is hampered by a lack of genetic tools that allow assessment of the mating and dispersal and genetic diversity of remaining stands. The three target species have partially overlapping ranges. " Acacia melvillei shrubland " endangered ecological community occurs in semiarid and arid eastern Australia. This community is considered threatened primarily because of se-nescence of the overstory (dominated by A. melvillei), infrequent seed set, and recruitment failure due to overgrazing (NSW Scientifi c Committee, 2008). Acacia pendula is more widespread, occurring throughout the eastern semiarid zone, but is considered threatened within the Hunter Valley (NSW Scientifi c Committee, 2008). In contrast, A. ligulata is one of the most widespread Acacia species, occurring throughout arid Australia. Seed set occurs annually in this species, recruits are common (personal observation), and most stands appear to be thriving (personal observation). For each of these species, we developed primers that amplify microsatellite loci. By comparing and contrasting the genetic structure of populations of these species with partially overlapping distributions and perceived variation in reproductive success, we aim to gain insights into the impact of anthropogenic disturbance on their genetic structure and diversity and, together with demographic assessments, will seek to use these data to predict the resilience of remaining stands. METHODS AND RESULTS We used GS FLX Titanium sequencing (Roche Diagnostics Corporation, Sydney, Australia) to generate databases of DNA sequences for A. melvillei and A. pendula. Specimens of each species were sourced from stands located in western New …