Exploring the origin and genetic representation of ex situ living collections of five endangered tree species established for 20–35 years

How well ex situ living collections capture the genetic variation of their wild-source populations, is an efficient indicator for assessing the success of ex situ conservation. Here, we explore the origins and genetic representation of multiple species' ex situ living collections that have been established for 20–35 years. We only sampled the potential wild-source populations, which cover parts of the focal species’ natural distribution ranges. Using microsatellite loci, we compared the genetic diversity between ex situ and wild populations, and verified the wild-source populations of ex situ living collections for five endangered tree species (i.e., Davidia involucrata, Dipteronia sinensis, Tetracentron sinense, Cercidiphyllum japonicum, and Tapiscia sinensis). We found that the genetic diversity of ex situ populations is comparable to their wild-source populations for all five plant species. We detected weak genetic structure among ex situ and wild-source populations for each species. Our results suggested that ex situ living plant collections may have comparable genetic diversity compared with their corresponding wild-source populations. We recommend that additional ex situ collections from different maternal lines across ex situ institutions or the distribution range of the target species would contribute to high level of genetic representation of ex situ populations, and (2) complete collection records and optimal sampling strategies are required for effective ex situ plant conservation.