Population structure in the endangered Mauna Loa silversword,Argyroxiphium kauense(Asteraceae), and its bearing on reintroduction

Abstract

Reintroduction of populations of endangered species is a challenging task, involving a number of environmental, demographic and genetic factors. Genetic parameters of interest include historical patterns of genetic structure and gene flow. Care must be taken during reintroduction to balance the contrasting risks of inbreeding and outbreeding depression. The Mauna Loa silversword, Argyroxiphium kauense, has experienced a severe decline in population size and distribution in the recent past. Currently, three populations with a total of fewer than 1000 individuals remain. We measured genetic variation within and among the remnant populations using seven microsatellite loci. We found significant genetic variation remaining within all populations, probably related to the recent nature of the population impact, the longevity of the plants, and their apparent self-incompatibility. We also found significant genetic differentiation among the populations, reinforcing previous observations of ecological and morphological differentiation. With respect to reintroduction, the results suggest that, in the absence of additional data to the contrary, inbreeding depression may not be a substantial risk as long as propagules for the founding of new populations are adequately sampled from within each source population before additional inbreeding takes place. The results further suggest that if mixing of propagules from different source populations is not required to increase within-population genetic variation in the reintroduced populations, it may best be avoided.

Microsatellite genetic variation in small and isolated populations of Magnolia sieboldii ssp. japonica

“…Population genetic variation in Swietenia humilis (A = 7.05, H o = 0.482; White et al, 1999) and the orchid, Gymnadenia conopsea (A = 6.97 and H o = 0.667; Gustafsson, 2000), were slightly higher than the results in this study. Argyroxiphium sandwicense, a narrow endemic and severely bottlenecked species, had lower intrapopulation genetic variation than the result of this study (A = 2.75, H o = 0.157; Friar et al, 2000).…”

“…Population genetic variation in Swietenia humilis (A = 7.05, H o = 0.482; White et al, 1999) and the orchid, Gymnadenia conopsea (A = 6.97 and H o = 0.667; Gustafsson, 2000), were slightly higher than the results in this study. Argyroxiphium sandwicense, a narrow endemic and severely bottlenecked species, had lower intrapopulation genetic variation than the result of this study (A = 2.75, H o = 0.157; Friar et al, 2000).The inbreeding coefficient (F IS ) was positive in most populations (Table 2). Genetic substructuring within a population might lead to positive F IS (Wahlund effect), however, this probability can be excluded because the autocorrelation analysis of the OMN1 population revealed no evidence of spatial clustering of alleles.…”

Genetic relationships of American alligator populations distributed across different ecological and geographic scales

“…Recent ecological and population studies of genetic variation in species of special concern have employed DNA microsatellite loci for evaluating patterns of genetic variation within and between populations (Dever et al, personal communication; Friar et al, 2001;Garnier et al, 2001;Lee et al, 2001;Sundqvist et al, 2001). Most conservation plans for these species have interpreted estimates of genetic diversity as a means of ensuring the maintenance of adaptive diversity and evolutionary potential in populations.…”

Genetic Evaluation of in situ Conserved and Reintroduced Populations of Wild Rice (Oryza rufipogon: Poaceae) in China

“…DNA marker technologies have been widely used in studies of genetic conservation and diversity (e.g., Fenster and Dudash, 1994;Robichaux et al, 1997;Hogbin et al, 1998;Friar et al, 2001;Li et al, 2002;Gao, 2004). Recently, much attention has been focused on applying genetic techniques to the design of conservation strategies for plant species with genetic and ecological importance (Falk and Holsinger, 1991;Fenster and Dudash, 1994).…”

“…Recently, much attention has been focused on applying genetic techniques to the design of conservation strategies for plant species with genetic and ecological importance (Falk and Holsinger, 1991;Fenster and Dudash, 1994). For example, genetic techniques have been applied in the design of sample strategies for ex situ collections or reintroduction activities (Ceska et al, 1997;Wolf and Sinclair 1997;Jin et al, 2003), reserve design (Sampson et al, 1988;Coates and Sokolowski, 1992), assessment of the conservation value and unit (Prober et al, 1990;Hogbin et al, 1998;Hogbin and Peakall, 1999), and the assessment of a reintroduction program (Robichaux et al, 1997;Friar et al, 2001).…”