Fritillaria gentneri population monitoring at Pickett Creek, Josephine County, Oregon

Over the twelve years of this study we have noted a startling drop in the number of flowering individuals of Fritillaria gentneri at the Pickett Creek population in the Medford District of Oregon. At the initiation of the study, in 2002, the population numbered above 400 reproductive plants with an estimated population size of 13,294 vegetative. The number of reproductive plants has declined over the years to a low of 46 in 2012 and only 68 in 2013; however, the number of vegetative plants has remained relatively stable. Population monitoring has been identified as a key recovery task in the species’ federal recovery plan (USFWS 2003)

While F. gentneri primarily reproduces vegetatively, recent work by the Oregon Department of Agriculture has shown that F. gentneri can produce viable fruits, and it has been well documented that mother bulbs can reproduce vegetatively creating hundreds of bulblets. Despite this, we have not seen any increases in the vegetative or reproductive populations over the twelve years of this study, and in fact have seen a shift towards smaller size classes and fewer flowering individuals.

The length of this study allows us to capture expected interannual variability driven by climate, and even allows for basic climate models to be created considering temperature and precipitation. We have been able to determine that the Pickett Creek population tends to thrive under warmer/drier fall and winter conditions which have not been experienced in recent years. However the fall and winter of 2013 look to be drier and warmer than previous years thus in 2014, we predict an increase in the number of vegetative and flowering individuals. While climate models can suggest potential influences on the population, they also suggest that the decrease in the reproductive population is not explained by climate drivers alone and thus it is likely that other environmental or biological variables are driving the alarming decrease in the number of flowering individuals.

We recommend that action be taken to preserve the Pickett Creek population of this sensitive species. The 2003 Recovery Plan includes both habitat manipulation (including prescribed fire) and reintroductions as potential management actions.