Published September 1, 2020 | Version v1
Dataset Open

Datasets for Mixed support for gene flow as a constraint to local adaptation and contributor to the limited geographic range of an endemic salamander

  • 1. Washington State University

Description

Understanding mechanisms that underlie species range limits is at the core of evolutionary ecology. Asymmetric gene flow between larger core populations and smaller edge populations can swamp local adaptation at the range edge and inhibit further range expansion. However, empirical tests of this theory are exceedingly rare. We tested the hypothesis that asymmetric gene flow can constrain local adaptation and thereby species' range limits in an endemic US salamander (Ambystoma barbouri) by determining if gene flow is asymmetric between the core and peripheries of the species' geographic distribution and testing whether local adaptation is swamped at range edges with a reciprocal transplant experiment. Using putatively neutral loci from populations across three core-to-edge transects that covered nearly the entire species' geographic range, we found evidence for asymmetric, core-to-edge gene flow along western and northern transects, but not along a southern transect. Subsequently, the reciprocal transplant experiment suggested that northern and western edge populations are locally adapted despite experiencing asymmetric gene flow yet have lower fitness in their respective home regions than center populations do. Conversely, southern populations exhibit low deme quality, experiencing high mortality regardless of where they were reared, likely due to harsher edge habitat conditions. Consequently, we provide rare species-wide evidence that local adaptation can occur despite asymmetric gene flow, though migration from the core may prohibit range expansion by reducing fitness in edge populations. Further, our multi-transect study shows that multiple, non-mutually exclusive mechanisms can lead to range limits within a single species.

Notes

dTable1: Diversity and genetic measurements for each collection stream using a subset of invidividuals. N = number of individuals, AR = allelic richness, Ho = observed heterozygosity, He = expected heterozygosity, ID = geo identification, Fis = inbreeded coefficient (+ highest and lowest value).

dTable2: Details of each metamorph collected from the experiment. Region = transplantation regions (Center, South, North, West), Position = block position, Cont. ID = container ID, Mass (g) = dry metamorph mass, Date = date of metamorphosis, TL = total length of metamorph, SVL = snout-vent length of metamorph, Gape = gape of metamorph.

dTable3: Water and air logger data from each site. Each transplantation site has the water temperature, light intensity, and air temperature for the entirety of the experiment. 

dTable4: Randomized block experiment design. Mapping of blocks and experimental setup for each transplantation site (tabs).

dTable5: Raw field notes for each visit to transplantation sites. Date of visit, transplantation site, block, remaining salamanders in container, total dissolved solutes, water pH, number of Dead salamanders observed, picture of salamanders, Notes, mass of salamanders.

dTable6: Input data for survival analysis. Each row indicates a dead salamader, obs is the number of days until death, treatment = transplantation treatment (center in center, south in center, west in center, etc.).

Files

dTable6_time_anal.csv

Files (1.6 MB)

Name Size Download all
md5:448fbd45828c5bb2afe1c50d2ea11e60
101.3 kB Download
md5:c42045de10fe8ae4f2978f2cfca67035
1.2 MB Download
md5:741a2dcd9b3f2cb982c715935bf601d3
68.6 kB Download
md5:50497423c3aae975b72f4fb16ed55db8
16.3 kB Preview Download
md5:4347e777b9b277f83b92d2ccfa39b318
11.0 kB Download
md5:4718a78bdb9f05680ce8e6f6a82e5c50
196.6 kB Download