Project Baseline: A living genome bank to capture evolution in action

Background/Question/Methods

Human activities such as development, pollution, and climate change have led to an increased rate of environmental change that is challenging the capacity of many plant species to adapt, disperse, and survive.  Studying how plant populations respond to changing conditions is difficult and time consuming, requiring several generations of propagation or comparisons of preserved historical propagules to those from current populations.  To enable the latter approach, Project Baseline is systematically collecting seeds from plant species across the country to store in the USDA National Center for Genetic Resource Preservation.  This seed bank will be available for future researchers to use in directly comparing historical and contemporary populations to assess the genetic basis for evolutionary change.  In our initial efforts, we wanted to answer two project questions:  1) Which plant species should be collected? and 2) What sites should we use for collecting seeds?  Because a severe drought occurred in 2012, we also sought to determine how this extreme weather event influenced germination rates in one of our focal species, Linum sulcatum.  To answer these questions, we surveyed plant biologists, mapped potential site locations, and collected seeds of L. sulcatum across a latitudinal and drought gradient to test germination viability.

Results/Conclusions

Based on input from plant biologists, we generated a preliminary list of 34 species for seed collection across the United States.  This list includes common species with widespread distributions as well as related congeners.  For collection areas, we judged that sites owned by the National Park Service, United States Forest Service, Bureau of Land Management, or The Nature Conservancy, as well as Long Term Ecological Research sites were preferred.  Not only do these sites allow seed collection, but in most cases these areas are protected from development and other human activities, providing some assurance that plant populations will be maintained for several decades.  Finally, germination rate of L. sulcatum was significantly decreased in areas facing drought, reaching less than 2% germination in the most severe drought areas compared to 20% germination rates in non-drought greenhouse conditions.  These data suggest that there may be strong and potentially devastating direct effects of extreme weather events on plant populations, and highlight the importance of collecting seeds for future studies.  By collecting and storing seeds from plant species across a wide geographic range, we will be able to directly test how – and if – plant populations are adapting to these changes.