Abstract Detail

Ecology

Olliff Yang, Rachael L. [1], Ackerly, David [2].

Population differentiation along abiotic gradients determines flowering time in Lasthenia gracilis.

The timing of cyclical life history events (phenology) is dynamic, and phenological traits can vary across a species range. Differences in phenology observed among populations in the field can be a result of genetics, the environment, or some combination of the two. The relative contributions of fixed and plastic traits on population flowering time may be important to consider for conservation and management practices. In this study, we examine the drivers of phenological differences across a species range, focusing on common goldfields (Lasthenia gracilis, Asteraceae), a species that is widespread in California grasslands, an important pollinator resource, and used frequently in restoration seed mixes. To test for population differentiation in phenology, we collected seed from 20 populations across the range of L. gracilis and examined variation in germination and flowering time under common growth conditions in a greenhouse. We recorded the germination date, the number of days to start, peak and end flowering dates, leaf length and plant height at first flower, and the total number of inflorescences across the growing season. We determine that populations of L. gracilis exhibit differentiation in flowering time, with number of days to start, peak and end flowering strongly related to source location temperatures and climatic water deficit (CWD; a measure of aridity). We then compared population flowering response observed in the common environment to differences observed in field flowering records sourced from herbarium specimens. The relationship of field flowering records to site temperature and CWD were greater in magnitude (steeper slopes) than the population differentiation observed in common environment conditions, revealing that population plasticity in response to local conditions plays an additional role in the timing of flowering in this species. Due to the existence of population differentiation in flowering traits, phenology may be important to consider in the design of conservation and land management plans, especially when sourcing L. gracilis seeds for restoration plantings.

1 - UC Berkeley, Department of Integrative Biology, 3040 Valley Life Sciences Building #3140, Berkeley, CA, 94720, United States
2 - Giannini Hall, Berkeley, CA, 94720, United States

Keywords:
Lasthenia
Restoration ecology
phenology
genetc differentiation.

Presentation Type: Oral Paper
Session: ECO1, Ecology 1: Phenology
Location: Virtual/Virtual
Date: Tuesday, July 28th, 2020
Time: 11:00 AM
Number: ECO1005
Abstract ID:822
Candidate for Awards:Ecological Section Best Graduate Student Paper