Reintroduction of the endangered and endemic plant speciesCochlearia bavarica—Implications from conservation genetics

Abstract

Population reintroduction is a common practice in conservation, but often fails, also due to the effects of inbreeding or outbreeding depression. Cochlearia bavarica is a strongly endangered plant species endemic to Bavaria in Germany, constantly declining since the late 1980s. Therefore, population reintroduction is intended. In this study, we analyzed genetic diversity within and genetic differentiation between all 32 remnant populations of the species in Swabia and Upper Bavaria using amplified fragment length polymorphisms. Our aim was to increase reintroduction success by providing data to avoid negative effects of inbreeding and outbreeding and to preserve the natural genetic pattern of the species. Genetic diversity within populations was low but similar to other rare and endemic species and varied strongly between populations but did not depend on population size. Our analysis revealed a strong geographic pattern of genetic variation. Genetic differentiation was strongest between Swabia and Upper Bavaria and at the population level, whereas differentiation between subpopulations was comparatively low. Isolation by distance and genetic differentiation was stronger among populations from Upper Bavaria than from Swabia. From the results of our study, we derived recommendations for a successful reintroduction of the species. We suggest using rather genetically variable than large populations as reintroduction sources. Moreover, the exchange of plant material between Swabia and Upper Bavaria should be completely avoided. Within these regions, plant material from genetically similar populations should preferably be used for reintroduction, whereas the exchange among subpopulations seems to be possible without a negative impact on genetic variation due to natural gene flow.

Associative Overdominance and Negative Epistasis Shape Genome-Wide Ancestry Landscape in Supplemented Fish Populations

“…In particular, individuals bred in captivity may adapt to captive conditions and can then develop genetic incompatibilities with their wild counterparts, leading to outbreeding depression when they are released into the wild [ 65 , 66 ], in addition to potentially diluting local adaptation. Indeed, outbreeding depression has previously been documented in wild populations following supplementation with captive populations [ 67 ], and these cases have received considerable attention from conservation biologists over the last three decades [ 20 , 68 , 69 , 70 , 71 , 72 ]. Here, it is therefore not surprising to detect in some genomic regions the molecular signature of negative epistasis since the domestic strain has been bred in captivity for more than 100 years (or at least 30 generations).…”

Looking for a successful translocation: the case of Astragalus edulis

“…As shown by Bobo-Pinilla et al (2018), this species exhibits a genetic pattern of three geographic areas (Iberian Peninsula, Morocco, and Canary Islands). As it is considered that the seeds from the same area will not affect the genetic pattern, the transference of plant material within these areas reduces the risk of outbreeding (Kaulfuß & Reisch, 2017). The phenotypic plasticity that can provide the adaptive traits of the species is generally unknown, and therefore conservation biologists still rely on quantitative genetic approaches to study phenotypic variation of endangered species and design efficient management programs (Noel et al, 2007).…”

Intentional introgression of a blight tolerance transgene to rescue the remnant population of American chestnut

“…Intentional introgression has previously been applied as a restoration strategy for both animals (Benson et al, 2011; Smith, Peterson, & Houston, 2003) and plants (Hamilton & Miller, 2016; Suarez‐Gonzalez, Lexer, & Cronk, 2018). However, most of these examples involve the introgression of broad genetic diversity into populations that were either severely restricted or locally extirpated (Hostetler et al, 2010; Kaulfuß & Reisch, 2017; Weisenberger, Weller, & Sakai, 2014). Uncontrolled introgression of multiple traits may result in various mixtures of desired, neutral, and undesired outcomes.…”