Abstract Detail

Ecology

Shriver, Laura [1], Leger, Elizabeth [1].

Assessing Rapid Evolutionary Response to Fire Through a Resurrection Study.

The cheatgrass (Bromus tectorum) invasion has significantly altered the Great Basin’s fire cycle. Great Basin native plants have difficulty re-establishing after repeated fires, but some can co-exist with cheatgrass and persist after fires. We asked if these plants are adapting to their post-fire landscape. Contrary to the long-held belief that evolution can only occur over large time-scales, many studies have documented rapid evolution in plants, including in response to fire and plant invasions.We examined change over time through a resurrection study, growing past (collected 3-11 years ago through Seeds of Success) and contemporary (re-collected from the same populations in 2020-2021) seeds in a common greenhouse environment. We compared germination and flowering % and timing between past/contemporary collections in sites that burned and unburned sites in similar habitats for Elymus elymoides, Pseudoroegneria spicata, and Sphaeralcea grossulariifolia. Germination timing showed results consistent with burning as a selective agent: for both grasses, the burned, contemporary collections were the fastest germinators, though irrespective of burn history, contemporary populations germinated faster than past collections. In contrast, the burned, contemporary Spharalcea grossulariifolia populations germinated slower than past collections while the unburned population was unaffected. Only the grasses flowered, and not all individuals flowered. The % of flowering in P. spicata populations was similar (20-28%) irrespective of collection time or burn. For E. elymoides, the unburned site had similar flowering propensity (<1%) in the past and present collections, but the burned site was more likely to flower in the past collection (52%) than the contemporary one (25%). These results are consistent with rapid evolutionary changes, due to selection or drift, and suggest that experiencing fire and surviving in a post-burn, cheatgrass-invaded landscape has altered their evolutionary trajectory.

1 - University of Nevada, Reno, Biology, 1664 N. Virginia Street, Reno, NV, 89557, USA

Keywords:
fire
Rapid Evolution
ecology
Great Basin
Ressurection study
invasive species
Cheatgrass.

Presentation Type: Oral Paper
Number: EC01004
Abstract ID:550
Candidate for Awards:None