Abstract Detail

Ecological Section

Vanderweide, Benjamin [1], Carter, Daniel [2], Ratajczak, Zakary [1], Ferguson, Carolyn [1], Mayfield, Mark [1].

Sensitivity of tallgrass prairie flora phenology to climate: inferences from historical observations and herbarium specimens.

Phenology shifts provide a powerful means for tracking vegetation responses to climate change, and have profound ecological implications. First flowering date (FFD) observations are frequently used in phenology studies because they often are the only available long-term record of vegetation phenology. However, these observations represent an extreme, and may poorly predict shifts in the more ecologically important measure of peak flowering date (PFD). We contend that herbarium specimen records appropriately characterize PFD, but have not been adequately tested as a source of phenological information. Using unique parallel records of FFD observations (n=261 species) and herbarium specimens (n=340 species) from northeast Kansas (1890s-present), we specifically test (1) if raw specimen records, cleaned specimen records (checked for flowering), and FFDs describe flowering distributions equally; and (2) if sensitivity to temperature varies depending on month of flowering. The flowering distribution of the entire flora and mean PFDs of individual species were described similarly by raw and cleaned herbarium records. The flowering distribution and mean FFDs from observations were shifted earlier relative to PFDs. In many cases raw herbarium records showed similar temperature sensitivity patterns as cleaned records, although raw specimen data was more variable and sensitivity to temperature disagreed with responses of cleaned records in some instances. We found that both early- and late-flowering species responded similarly to spring warming, but only late-flowering species delayed flowering in response to summer warmth. However, late-flowering species appeared insensitive to mean annual temperatures, thus masking this intra-annual variation in temperature sensitivity. We found that cumulative sensitivity to monthly temperature increased with mean FFD, but cumulative sensitivity of PFD was greatest in mid-summer. We found strong correlations between cumulative sensitivity of PFD and soil moisture. Our findings highlight the utility of herbarium records in phenology studies. Raw specimen label information (date and location) can be used to estimate flowering distributions of a flora and mean PFD of individual species, but raw specimen records may be misleading if used to study sensitivity to temperature. Cleaned herbarium records estimate mean PFD and temperature sensitivity well, and should be paired with FFDs to better understand potential ecological implications of phenology shifts. We also demonstrate the need to better incorporate timing of temperature and moisture variability and possible divergent responses into phenology research.

Broader Impacts:

1 - Kansas State University, Division of Biology, 116 Ackert Hall, Manhattan, , KS, 66506, USA
2 - The Nature Conservancy, C/O Eastern Oregon Agricultural Research Center, 67826-A Hwy. 205, Burns, OR, 97720, USA

Keywords:
phenology
Climate Change
First Flowering Day
peak flowering
herbarium
specimen database
temperature sensitivity.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:45 PM
Number: PEC009
Abstract ID:333
Candidate for Awards:Ecological Section Best Graduate Student Poster