Abstract Detail


Suglia, Elena [1], De La Pascua, Danielle [2], Strauss, Sharon [3], Schmitt, Johanna [4], Gremer, Jennifer [5].

Phenological responses to variable timing and frequency of herbivory in a native wildflower.

In the face of rapid global change, a crucial question in ecology and evolution is how species will respond to changes in climate and resulting novel combinations of abiotic and biotic conditions.  Changes in plant phenology and plant-herbivore interactions are already occurring due to climate change and have the potential to impact species interactions, individual fitness, and population dynamics. While it is well understood that biotic interactions influence plant phenology and fitness, little is known about how within-species differences in herbivory regimes affect intraspecific phenological variation and the resulting consequences for life history expression and population connectivity. Here, we examine population-level responses to herbivory regime in Streptanthus tortuosus, which experiences a wide range of variation in herbivory timing, frequency, and intensity and displays variable fitness and phenological responses to herbivory across time and space in the field. We conducted a common garden experiment mimicking mammalian herbivory on individuals from three alpine populations of S. tortuosus to determine the effects of varying timing and frequency of herbivory on phenology, fitness, and life history.Our results suggest that timing and frequency of herbivory significantly affects both flowering time and fitness. Individuals that experienced herbivory flowered significantly later than controls, and individuals experiencing later or more frequent herbivory experienced the most pronounced delays in flowering. Additionally, herbivory depressed fecundity in all treatments, and individuals exposed to more frequent herbivory experienced a significant reduction in fecundity. This suggests that plants are unable to compensate when herbivorized, especially when tissue damage occurs multiple times throughout the season. Plants were also more likely to survive for longer periods of time in response to herbivory (significantly so if herbivorized more than once), potentially leading to increased perenniality and iteroparity. Overall, results suggest that individual variation in the timing and frequency of herbivory impacts population-level variation in phenology, fitness, and life history. Future plant phenological responses to climate change will depend on how the timing of biotic pressures interacts with changing environmental conditions. If plants and their herbivores respond differently to changing environmental cues as summers become drier and hotter in alpine regions, such varying responses may alter temporal overlap between plants and herbivores, affecting plant fitness and persistence. Understanding the abiotic and biotic factors that currently drive phenological responses is essential for accurately predicting the potential for adaptation to future climate-induced environmental change.

1 - University of California, Davis, Evolution and Ecology, 3432 Koso St, Davis, CA, 95618, United States
2 - University of California Davis, Population Biology, Davis, CA, 95616
3 - UC Davis, DEPT OF EVOLUTION AND ECOLOGY, One Shields Avenue, Davis, CA, 95616, United States
4 - University Of California, Davis, Evolution And Ecology, 1619 Tamarack Lane, Davis, CA, 95616, United States
5 - 902 Gregory Place, Davis, CA, 95616, United States

life history

Presentation Type: Poster
Session: P, Ecology Posters
Location: Virtual/Virtual
Date: Tuesday, July 28th, 2020
Time: 5:00 PM Time and date to be determined
Number: PEC003
Abstract ID:187
Candidate for Awards:None

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