Ημερολόγιο της/του hkibak

Introduction

Garrya elliptica (Coast Silk Tassel) is a dioecious wind-pollinated shrub to small tree locally common in Maritime Chaparral and Oak Woodland along the coast of California and Oregon (1,2). Successful seed production requires that dioecious plants, as well as plants that need to cross-pollinate, flower at the same time when pollen is being shed and stigmata are receptive. Because exposing delicate reproductive organs such as stigmata and anthers to desiccation can be stressful in times of drought, deferring flowering until conditions are better could be adaptive. No pollinator is needed in the case of Garrya elliptica, so flowering is not constrained to times when a pollinator is present. Flowering could hypothetically vary according to soil moisture in an individual plants root zone.

Most Fort Ord soils are Loamy Sands with a plant available water capacity of about one inch per foot of soil profile. Since most plants get most of their water from the upper 18" of soil and some evaporation and runnoff could be expected, I chose two inches of precipitation as the threshold for soil moist enough to trigger normal growth activity in shrubs and trees in the Fort Ord area. In practice, this threshold seems to work (me checking with a shovel and observing new growth in chamise, coffeeberry, manzanita, oak, and silk tassel).

Hypothesis: Flowering in Garrya elliptica is sensitive to soil moisture.

Test: If flowering in Garrya elliptica is sensitive to soil moisture then flowering should begin later in years where significant rains come later.

Based on experience, the soil profile at Fort Ord is not moist in the Fall until 2" of rain has accumulated (A).

Q1: When did the soil profile become moist in the Fall each study year?(A)
During the Water Year 2022-2023 Fort Ord had accumulated 2 inches of rain by November 9, 2022 (A)
During the Water Year 2023-2024 Fort Ord had accumulated 2 inches of rain by December 20, 2023 (B)
In the Fall of 2022 Fort Ord soil was moist 41 days earlier than in the Fall of 2023.

Q2: How much later will flowering begin in 2024 because water came 41 days late?

Tools

Fort Ord Garrya elliptica https://www.inaturalist.org/observations?place_id=163575&taxon_id=53399
Fort Ord known females https://www.inaturalist.org/observations?place_id=163575&taxon_id=53399&term_id=9&term_value_id=10
Fort Ord known males https://www.inaturalist.org/observations?place_id=163575&taxon_id=53399&term_id=9&term_value_id=11

iNaturalist observations of the same *Garrya elliptica* over time: (incomplete. Will continue as spreadsheet)

@asauble Jan 3, 2023 Male Fully flowering https://www.inaturalist.org/observations/145778755
@fredwatson Jan 8, 2023 Male Fully flowering https://www.inaturalist.org/observations/146171533
@hkibak Jan 13, 2024 Male Incipient flowering https://www.inaturalist.org/observations/196636265

@fredwatson Jan 9, 2023 Male Fully flowering https://www.inaturalist.org/observations/146243108
@hkibak Jan 12, 2024 Male (presumed) Budding https://www.inaturalist.org/observations/196477795

@hkibak Apr 11, 2020 Male fully flowering https://www.inaturalist.org/observations/41975327
@hkibak Jan 13, 2024 Male flower budding https://www.inaturalist.org/observations/196789187

@yerbasanta Feb 18, 2023 flowering https://www.inaturalist.org/observations/149279041
@hkibak Jan 16, 2024 female flowering https://www.inaturalist.org/observations/196996047

References (#) and Footnotes:

(A)
(B) https://www.inaturalist.org/journal/hkibak/86783-fort-ord-national-monument-precipitation-water-year-2024
(1)Thomas F. Daniel 2012, Garrya elliptica, in Jepson Flora Project (eds.) Jepson eFlora, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=26460, accessed on January 14, 2024.
(2) Jepson Video https://www.youtube.com/watch?v=LFVGFzBwczw
(3) Kemal Kazan, Rebecca Lyons, The link between flowering time and stress tolerance, Journal of Experimental Botany, Volume 67, Issue 1, January 2016, Pages 47–60, https://doi.org/10.1093/jxb/erv441
(4) Fiona Tooke, Nicholas H. Battey, Temperate flowering phenology, Journal of Experimental Botany, Volume 61, Issue 11, June 2010, Pages 2853–2862, https://doi.org/10.1093/jxb/erq165
(5) Freeman, D. C., McArthur, E. D., & Harper, K. T. (1984). The Adaptive Significance of Sexual Lability in Plants; Atriplex canescens as a Principal Example. Annals of the Missouri Botanical Garden, 71(1), 265–277. https://doi.org/10.2307/2399070

The California Coastal Bush Lupine Lupinus arboreus is subject to some major aphid infestations ( https://www.inaturalist.org/observations/80203682 ) primarily of Macrosiphum albifrons (the Lupine Aphid) and the local Lady Bird Beetles seem to "know" this. If I want to see a variety of Lady Bird Beetles this time of year I just head over to a patch of Coastal Bush Lupines and begin looking for orange. I didn't find any aphids this time, but the Lady Bird Beetles were there anyway, searching.