Natural Deaths of Lemon Lilies, Lilium parryi

Fig. 1. Steve Taylor photographed three lemon lilies in bloom between Candy's Creek and this very distinctive boulder in 2010, on the Lemon Lily Tour led by Dave Stith as part of the Idyllwild Lemon Lily Festival. In 2020, a follow-up observation by Tom Chester showed that stream erosion had removed the soil and the plants. In both photographs, you can see the water of the creek itself, at lower left and upper left, creating openings in the otherwise dense vegetation along the banks. The photographs are looking downstream, so the erosive power of the water is greatest at the curve immediately left of the boulder.
Click on the pictures for larger versions showing a larger area.


Table of Contents

Introduction
Gophers
Erosion
Sediment Deposition
Bulb Splitting


Introduction

This page documents the natural deaths of lemon lilies that we have observed over the years. It was just begun on 7 August 2020 to present the pictures shown in Fig. 1, and discussed a bit in the Erosion section. The rest of this page will be slowly added in the future.

Gophers

Gophers are probably the major mortality cause for lemon lilies. Gophers love to eat lemon lilies, and if they have access to a lemon lily, it will eventually be a goner. They are such efficient predators that lemon lilies are primarily only observed in places gophers cannot access, such as cracks in boulders, places where the ground is too moist for them to build tunnels, and places protected from gopher access, such as islands in streams, or areas surrounded by boulders and/or streams.

The example below is taken from The at-least-20 year old Munchkin Lemon Lily on the Devils Slide Trail page.

Prior to the drought, the seep area in which the Munchkin lemon lily grows used to regularly make this section of the Devils Slide Trail muddy, and there would often be standing or even flowing water on the trail even in late summer; see photo of water on the trail on 30 August 2010. Even in the first year of the drought, in 2012, the seep became dry enough to allow gophers to enter the area. By the second year of the drought, in 2013, with its very low rainfall, the former seep area was dry, and nearly barren of plants.

Fig. 2 shows the change in the seep area between 2006 and 2016, and Fig. 3 shows a gopher decimating the area in 2012.

Fig. 2. Change in the uppermost seep on the Devils Slide Trail between 2006 and 2016. Left: The abundant water in the seep in 2006 produced the dense growth of moisture-loving species such as Agrostis idahoensis and Mimulus moschatus. Right: After five years of drought and predation by gophers, all the moisture-loving species are gone, leaving mostly bare dirt and a few plants of Carex fracta which can survive with less water and are probably unpalatable to gophers. Click on the pictures for larger versions.

Fig. 3. The seep area was dry enough on 16 June 2012, the first year of our five year drought, for a gopher to eat the plants in the seep, which are normally protected from gophers by the saturated soil. Left: a portion of the seep showing the many gopher mounds, with the culprit shown in the white circle. Right: Closeup of the tunneling terrorist. Click on the pictures for larger versions.

Erosion

Erosion probably paid a large role in killing lemon lilies after the 2013 Mountain Fire. The much-increased sediment load and water runoff changed the dynamics of the water courses here, resulting in erosion in many places with resulting sediment deposition in others. The Mountain Fire itself was largely finally extinguished by heavy rainfall from the intense thunderstorms induced by the strong upward motion of the air above the still-burning Mountain and monsoonal moisture.

We have had several other unusually-intense scouring storms at San Jacinto in the last decade, some of them also unusual in being warm rain storms, instead of the usual winter gentle snows. Global warming almost certainly is a factor for both of these. A notable example is the warm intense rainfall of February 14, 2019 that wiped out major portions of SR243 and SR74, resulting in the need for major reconstruction for both of those highways. Another example was a very unusual heavy warm rainfall event in April 2020 that scoured a number of streambeds.

Fortuitously, Steve Taylor photographed three lemon lilies in bloom between Candy's Creek and a very distinctive boulder in 2010, on the Lemon Lily Tour led by Dave Stith as part of the Idyllwild Lemon Lily Festival that year. Tom Chester relocated that boulder in 2020, and found not only that those lemon lilies had disappeared, the entire soil bank at that location was missing; see Fig. 1.

We of course don't know when that erosion occurred, except that it happened after 2011 when Tom by happenstance photographed the same lilies. But the mechanism is quite clear. Those lilies were located on the outer bank of a curve in the river, which is the place subjected to the most erosive force.

We thank Steve Taylor for permission to use his photograph in Fig. 1.


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Copyright © 2020 by Dave Stith and Tom Chester.
Commercial rights reserved. Permission is granted to reproduce any or all of this page for individual or non-profit institutional internal use as long as credit is given to us at this source:
http://tchester.org/sj/species/lilium_parryi/deaths.html
Comments and feedback: Tom Chester
Updated 7 August 2020.