Conservational status of Cotoneaster wilsonii on Island Ulleung - do

Abstract

The shrub plant, Cotoneaster wilsonii Nakai, endemic to Ulleung-do of East sea in Korea in considered a rare plant. Distribution of genetic variation and ecology were investigated in two populations (only total 84 individuals) using 13 allozyme enzymes to better understand its population biology and to comment on management proposals relevant to this species. Measures of genetic variation in this species were lower than values reported for species with similar ecological and life history traits(ca. 15 % of loci polymorphic within populations, 1.21 alleles per polymorphic locus, and 0.42 expected heterozyogsity, respectively). A total of 17 putative loci were scored, but only three loci were polymorphic in at least one population. We examined all patterns of genotypes from these two populations where nine and seven genotypes(11 genotypes from all 84 individuals) were detected. We have applied the IUCN Red list criteria to this species based on this current inventory. Since C. wilsonii in Korea was treated as an endemic (sensu stricto) or a synomized taxon to central Chinese species, C. multiflorus (sensu lato), we applied these sensu lato (sl) and sensu stricto (ss) concepts to this taxon. C. wilsonii(ss) were evaluated as Critically Endangered(CR), while C. multiflorus turned out to be Least Concern(LC) due to the abundant individuals and wide distribution in central China. The current population genetic structure was probably a result of a population bottleneck at colonization or the result of local extinction of intervening populations and the small effective population size with the recent human disturbance. The mating system of Cotoneaster is known largely as apomixes. The lack of diversity we found within populations is consistent with genetic bottleneck, especially combination with the evidence for apomixes. More speculative possibility, is that these populations have always been relatively small and isolated, with the capacity to maintain levels of genetic variability in association with partly outcrossing as well as apomixes. To preserve extant variation in this species, sampling of minimum 28 individuals out of 84 individuals randomly in order to obtain 90% genetic diversity would be essential for maximizing the level of genetic variability for ex situ conservation.