Salvia pentstemonoides (big red sage) is a highly threatened (NatureServe G1, the most critical threat level) plant native to Texas. There are less than 10 populations (perhaps only approximately 5) in existence. Only two of these populations exceed 100 plants; the remaining populations are all less than 50 plants. All populations are in unstable riverine or bluff habitat. Big red sage is beautiful and charismatic and is found in botanic gardens and in nursery catalogs. Thus the species is an interesting case of a plant that is highly threatened in the wild but possibly secure ex situ. In addition, it is of note that Salvia is a genus with many plants of high value in medicine and food, in addition to horticultural value.
This study aims to:
- Determine whether the small populations have lower genetic diversity and/or higher inbreeding than the larger populations. The hypothesis is that the larger populations would have higher diversity and thus be more genetically healthy.
- Compare the genetic diversity in wild populations to those in nurseries and botanic gardens. The hypothesis is that genetic diversity will be lower in the ex situ collections, but it is possible there is equal, or more genetic diversity, preserved ex situ. We also predict that cultivated collections will have highly related individuals (mostly siblings), which could lead to inbreeding in the future.
Knowledge derived from this study will help in situ and ex situ management of this highly threatened plant to ensure its survival.