Abstract Detail

Conservation Biology

Edwards, Christine [1], Bassuner, Burgund [2], Yatskievych, George [3].

Not everything is bigger in Texas: Conservation genetics and the genetic distinctiveness of the endangered Texas trailing Phlox (Phlox nivalis ssp. texensis).

Phlox nivalis ssp. texensis (Texas trailing Phlox) is a perennial herb endemic to longleaf pine savanna woodland communities, found only in three counties in Texas. P. nivalis ssp. texensis has experienced declines as the result of habitat loss and degradation from development, agriculture, timber removal, invasive mammals, and fire suppression, such that currently only a few small populations remain; the USFWS thus designated P. nivalis ssp. texensis as Endangered in 1991. Despite its rarity, the genetic diversity contained in wild and reintroduced populations of Texas trailing phlox, patterns of genetic structure, and whether the taxon is genetically distinct from the other subspecies of P. nivalis are currently unknown. The goals of this study are to: 1) understand levels of genetic diversity and structure, 2) analyze the genetic distinctiveness and relationships among the subspecies of P. nivalis and related Phlox species, and 3) devise a strategy to protect the genetic variation of P. nivalis ssp. texensis and establish genetically viable reintroductions. We visited every possible wild historical occurrence of P. nivalis ssp. texensis, but many populations have been extirpated. We relocated and collected 261 samples from five remaining populations of P. nivalis ssp. texensis, We also sampled from reintroduced populations of P. nivalis ssp. texensis and from 5 populations of the other subspecies of P. nivalis in FL, GA, and SC, resulting in a total of 436 samples, which were genotyped at 23 microsatellite loci. Allelic patterns indicate that polyploids are prevalent throughout the species’ range and that P. nivalis represents a polyploid complex, containing putative diploid, triploid, tetraploid, and hexploid individuals; the consequences of variation in ploidy on reproductive success in P. nivalis ssp. texensis merits additional study. Some individuals or populations, particularly reintroduced populations, also appear to be partially clonal. Results indicate that despite its rarity, significant genetic diversity remains in P. nivalis ssp. texensis, and it contains unique alleles not found in the sampled populations of the other subspecies of P. nivalis. Despite retaining high genetic diversity, our study suggests that P. nivalis ssp. texensis is declining and that intensive management of its habitat is desperately needed to prevent its extinction. We also make recommendations about the prioritization of in situ and ex situ conservation efforts based on the results.

1 - Missouri Botanical Garden, 4344 Shaw Blvd, Saint Louis, Missouri, 63110, United States
2 - Missouri Botanical Garden, 4344 Shaw Blvd, Saint Louis, MO, 63110, United States
3 - University Of Texas At Austin, Billie L. Turner Plant Resources Center, Main Bldg Rm 127, 110 Inner Campus Dr, Stop F0404, Austin, TX, 78712, United States

Keywords:
conservation
endangered species
population genetics
polyploidy
Genetic diversity
longleaf pine savannah.

Presentation Type: Oral Paper
Number: CB1005
Abstract ID:704
Candidate for Awards:None