Genetic variation in remnant Festuca hallii populations is weakly differentiated, but geographically associated across the Canadian Prairie

Abstract

Genetic diversity is essential for predicting plant evolutionary potential and for formulating conservation strategies. However, little is known about the genetic variation of plains rough fescue [Festuca hallii (Vasey) Piper], a widespread and diagnostic grass in the Fescue Prairie. We used the amplified fragment length polymorphism (AFLP) technique to assess the genetic variation of 30 fragmented populations of F. hallii across the northern Canadian Prairie and its associations with 12 geographical, fragmentation and environmental attributes. Three AFLP primer pairs were used to screen 840 samples, representing approximately 30 samples from each population, and 246 polymorphic bands were scored. The fescue plant was genetically diverse, as revealed by the proportion of polymorphic bands (0.870-0.967), the mean band frequency (0.364-0.457) and the within-population variation (69.4-85.4). The genetic variation was not highly differentiated, with only 6.5% of the total AFLP variation residing among populations. A Mantel test revealed a significant correlation between genetic and geographical distances (r = 0.39; P < 0.004) and a spatial autocorrelation up to 60 km among populations was detected. The AFLP variation displayed a longitudinal decline and was significantly associated with environmental attributes related to moisture, indicating local adaptation. However, the AFLP variation was not significantly associated with the estimated population size and geographical distance to the nearest neighbor, suggesting that fragmentation has not generated considerable genetic impact on the fescue populations. Implications for fescue conservation, restoration and management are discussed.

Genetic Structure of Remnant Populations and Cultivars of Switchgrass (Panicum virgatum) in the Context of Prairie Conservation and Restoration

“…Despite the size differences among remnant wild populations of switchgrass (approximately 2-2,590 ha), no significant differences in genetic diversity were observed among these populations. Similar findings have been reported in other perennial prairie species (Gustafson et al 1999;Gustafson et al 2004;Selbo & Snow 2005;Moncada et al 2007;Qiu et al 2009). These results suggest that small, remnant prairie populations do not necessarily harbor less genetic diversity compared to larger populations, although cases of genetically depauperate small plant populations are also known (Sytsma & Schaal 1985;Lammi et al 1999;Chang et al 2005).…”

Genetic Risk Assessment of a Threatened Remnant Population of Hairy Prairie-Clover (Dalea villosa var. villosa) in the Canadian Prairie

“…are both highly outcrossing, being pollinated by a diversity of bee and fly species [45]. Such a high level of AFLP polymorphism is expected for an outcrossing plant species [46] and is compatible with those AFLP findings reported in other outcrossing plant species native to North America [27][28][29]47,48]. …”

“…These findings indicate that these patch characteristics may not directly contribute to the change in within-patch AFLP variation if any. A patch of several plants should maintain considerable genetic variation [48]. Figure 5.…”

“…Given the finding of large AFLP variation and the nature of outcrossing, however, it is not difficult to reason that the genetic risk may be relatively low for the other remnant populations in the Canadian Prairie [48]. Further genetic and ecologic studies with more populations in the northern range of the species distribution should yield more useful information to identify the potential risks of the remnant populations.…”

Genetic Resources of Crop Wild Relatives: A Canadian Perspective

“…A molecular research program on native Canadian grass species in association with PGRC has existed since 2002 in collaboration with other scientists in AAFC, National Parks, Environment Canada, the University of Saskatchewan, and Ducks Unlimited to conduct 11 research projects on genetic diversity of more than 14 native grass species (Fu et al 2005a;Fu and Thompson 2006;Liu et al 2013;Biligetu et al 2013). Observations of diversity changes over time and space are helpful to make conservation decisions for such plant material (Ferdinandez et al 2005;Fu et al 2005b;Qiu et al 2009). This advanced knowledge about native grass species contributed to Canadian forage breeding and native grass conservation and restoration.…”