Abstract Detail

Conservation Biology

Radford, Zachary [1], Sullivan, Lauren [2], Moeller, David [3].

Fine-scale maintenance of adaptive genetic variation despite gene flow in a remnant tallgrass prairie.

Local adaptation is well-known to occur at broad spatial scales but remains poorly understood over fine spatial scales (within populations) where rates of gene flow are high. Evaluating fine-scale spatial patters of adaptive genetic variation has important applied implications for the conservation of isolated populations in highly fragmented landscapes. To understand local adaptation in smaller, more isolated populations, we focus on Ratibida columnifera, a common grassland perennial native to North America. We used field, greenhouse, and sequencing studies on  Ratibida columnifera (Asteraceae), a perennial forb, from a prairie fragment isolated in a matrix of agriculture. We examined whether there is quantitative genetic variation in ecologically-important traits, tested whether that variation correlates with microhabitat variation, and quantified the scale of gene flow. Greenhouse-grown plants revealed evidence of significant genetic variation among maternal families for flowering time, seed mass, and leaf dissection index. For all three traits, phenotypic variation exhibited significant spatial autocorrelation. Notably, genetic variation in flowering time was significantly correlated with microtopography (301.3 - 304.1 meters) where early flowering genotypes were found at minimum and maximum elevations and late flowering genotypes were found near median elevations. We then used genotyping-by-sequencing to determine the spatial scale of population genetic structure. Spatial principle component analysis (sPCA) and mantel correlograms revealed significant spatial autocorreltaion of genetic variation across space. These results suggest that spatial variation in natural selection is stronger than the homogenizing effect of gene flow, despite the very fine-scale over which our study was conducted and significant isolation from other populations. Taken together, our results provide evidence for fine-scale adaptive differentiation within a prairie fragment and suggest that adaptive genetic variation can be maintained even in a fragmented landscape where the environment appears to be highly homogenous.

1 - University of Minnesota, Plant and Microbial Biology, 140 Gortner Laboratory, 1479 Gortner Avenue, St. Paul, MN, 55108, USA
2 - University of Missouri, Biological Sciences, 105 Tucker Hall, Columbi, MO, 65211, USA
3 - Department Of Plant And Microbial Biology, 1479 Gortner Avenue, St. Paul, MN, 55108, United States

Keywords:
local adaptation
gene flow
Landscape genetics
conservation
remnant
non-model
grassland forb.

Presentation Type: Poster
Session: P1, Conservation Biology Posters
Location: Virtual/Virtual
Date: Monday, July 19th, 2021
Time: 5:00 PM(EDT)
Number: P1CB012
Abstract ID:790
Candidate for Awards:None