Effect of habitat fragmentation on the genetic diversity of Stipa krylovii Reshov. in an agro-pastoral ecotone in northern China

Abstract

Z. 2009. Effect of habitat fragmentation on the genetic diversity of Stipa krylovii Reshov. in an agro-pastoral ecotone in northern China. Can. J. Plant Sci. 89: 875Á882. Native grassland in China have been fragmented due to the introduction of agriculture, which has the potential to reduce genetic diversity. In order to understand the potential effects of fragmentation, we conducted a study to examine the genetic diversity between two populations of Stipa krylovii in a typical steppe ecoregion, in northern China. One population was fragmented by farmland (PF) while the second was continuous steppe (PS). The populations were 30 km apart. Genetic diversity was assessed by sampling plants in four geographically similar subpopulations in each population and analyzed for their DNA using the inter-simple sequence repeats (ISSR) markers. Of 50 primers tested, 7 produced 122 amplified bands from 120 individuals, of which 92% (112) were polymorphic. According to the UPGMA dendogram, the four PF subpopulations were grouped separately from the four PS subpopulations. However, AMOVA analysis indicated that habitat fragmentation over the past 50 yr had not changed genetic diversity and variation among S. krylovii populations in an agro-pastoral ecotone in northern China. Therefore, the genetic diversity of this species can be maintained if agriculture disturbance is not increased.Key words: Genetic variation, gene flow, ISSR, fragmented population, non-fragmented population Zheng, S., Wang, K., Zhao, M., Mi, J., Sui, X., Feng, Y. et Cao, Z., 2009. Incidence du fractionnement de l'habitat sur la diversite´ge´ne´tique de Stipa krylovii Reshov. dans un e´cotone agropastoral du nord de la Chine. Can. J. Plant Sci. 89: 875Á882. En Chine, l'ave`nement de l'agriculture a fractionne´les prairies naturelles, ce qui pourrait susciter une diminution de la diversite´ge´ne´tique. Pour comprendre les conse´quences e´ventuelles d'un tel fractionnement, les auteurs ont entrepris une e´tude sur la diversite´ge´ne´tique de deux populations de Stipa krylovii dans une e´core´gion typique a`la steppe du nord de la Chine. Une population (PF) avait e´te´fragmente´e par des terres agricoles alors que la seconde (PS) formait une steppe continue, les deux e´tant distantes de 30 kilome`tres. On a e´value´la diversite´ge´ne´tique en e´chantillonnant les plants de quatre populations secondaires ge´ographiquement semblables au sein de chaque population et en analysant leur ADN graˆce a`des marqueurs ISSR (amplification intermicrosatellite). Sur les 50 amorces teste´es, 7 ont donne´122 bandes chez 120 individus dont 92 % (112) e´taient polymorphes. Selon le dendogramme UPGMA, les quatre sous-populations PF forment un groupe distinct des quatre sous-populations PS. Ne´anmoins, l'analyse de la variance mole´culaire (AMOVA) indique que le fractionnement de l'habitat survenu au cours des 50 dernie`res anne´es n'a modifie´ni la diversite´ni les variations ge´ne´tiques observe´es chez S. krylovii dans l'e´cotone agropastoral du nord de la Chine. Par conse´que...

Genetic diversity and relationships among populations of Camellia japonica, an endangered species in China

“…A study of Argyroxiphium sandwicense ssp. sandwicense on the island of Hawaii indicated that diversity was closely related to environmental differences; the pressure of natural selection was strong, and the genetic diversity was high (Friar et al 2010;Zheng et al 2010). Since the third century, climate change has produced variable and complex environmental conditions for C. japonica (Naidong).…”