Recent Findings and Community Support

We received a very generous donation last summer.   Laboratory & greenhouse research, and extensive regional die-off site surveys provide new insight into the nature and extent of the ongoing sword fern die-off.   Herewith an update.

• The Seattle branch of 100 Women Who Care raised almost $8000 to support research into the cause and nature of the sword fern die-off.  We were delighted.  We are grateful!
• Forest ecologist Dylan Mendenhall (trained at UW and UBC, himself once a Seattle Parks GSP forest steward at Schmitz Preserve) has conducted pro bono research at the UW CUH greenhouse over the last two months.    Greenhouse rental fees and material costs were paid for out of the 100 WWC donation.   Dylan tested the hypothesis first raised in the ad hoc beer-bottle experiment: that the die-off effect can be transmitted in water from an affected frond to a healthy frond.   Dylan's experiments proved this hypothesis, at scale, and with rigor - a huge breakthrough in our ongoing effort to determine the cause of the regional PNW lowland sword-fern die-off.  High resolution microscopy and metagenomic sequencing are likely next steps.
• Reed College undergraduate researcher Caleb Goldstein-Miller, working under the guidance of Professor Aaron Ramirez, spent many weeks over the summer, and some subsequent time in the lab, on two topics: a regional die-off site survey, and ecophysiological water relations.   The results of the regional survey may be seen in this map.  (UW students and Dr. Tim Billo assisted in the survey.)  Caleb summarized the ecophys lab work: "[W]e are confident in our conclusion that moisture stress is not driving the die off at Seward Park. This increases our confidence that the regional decline is caused by some still unknown biotic vector".
• Seattle Parks ecologist Lisa Cieko led (and continues to guide) a crucial response to the die-off at Seward Park: the ecological restoration of the original die-off site, "Ground Zero".  About 100 native plants of mixed species were installed, mulched, then watered over the summer, with thus far good survival rates.  In combination with the 24 sword ferns we planted in February of 2018 - which have a nearly 100% survival rate - Ground Zero is no longer the barren, non-regenerating  slope it was for several years.  In addition, a few fringecups have sprung up in the first instance of natural regeneration. 

Visit to NatureBridge School in Olympic National Park

With an invitation from education manager Chris Morgan, I paid a visit and gave a talk to the educational staff at NatureBridge, on the shore of Lake Crescent.   I had an engaging exchange with about twenty staff members, all of them environmental educators whose mission

"is to connect young people to the wonder and science of the natural world, igniting self-discovery and inspiring stewardship of our planet. Through our overnight, hands-on environmental science programs, we take more than 35,000 children and teens each year into our national parks to explore the outdoors, connect with their peers, discover themselves and develop a lasting relationship with the environment." 

The low elevation mature and old-growth forests surrounding Lake Crescent are healthy.  Sword ferns dominate large areas of undergrowth - with no sign of any die-off.

We emerged from this meeting, which concluded with a walk in the woods, with a tentative plan: that NatureBridge staff and their students may contribute to understanding the die-off, and more fundamentally to the understanding the ecology and biology of sword ferns, through careful  observations over the coming years. 

Some of the topics we discussed:

1.  Sword ferns rarely reproduce under a closed forest canopy.  See Robbin Moran's  Natural History of Ferns report that the prothallus (the gametophyte) needs recently exposed bare soil (and presumably ample sunlight) for propagation.  
2. Individual plants (the familiar sporophyte generation) are very long-lived ("a thousand years is not out of the question" - David Barrington, University of Vermont polystichum expert)
3.  Are there any signs of fern mortality, or propagation, in the healthy fern communities in Olympic National Park?  To suppport or contradict topics 1 and 2?

 We know little about the variability of the annual life cycle of healthy ferns and their fronds.   Perhaps a multi-year phenology project would be a good match for NatureBridge students?   A combination of careful observation in the forest, data collection, hypothesis generation and testing?

In this scenario, student scientists, backed up by trained academics (we have contacts with some helpful ones) could contribute new understanding of this signature PNW species, and provide baseline and background information we need to explore the die-off

Is there a pattern to the 10% sword fern survival at Ground Zero?

In 2013, 215 large healthy sword ferns occupied the understory of the quarter-acre of Seward Park's Ground Zero.  Twenty of those ferns survive six years later. Is there a pattern to that survival, perhaps some clue to the cause of the die-off?  It appears that proximity to trees or logs correlates with survival - but does that stand up to close inspection?  We found that there is a small but statistically significant association.

In this map dead ferns are black circles, survivors are in light green, trees are larger solid circles, and logs are thick black lines.

Leo Shannon and I collected the location and status of all ferns, trees and logs in this quarter acre on May 18th and 19th, 2019.   Dylan Mendenhall did the analysis.   Results are summarized below the map.

Dylan's summary and suggestions:

The survival rate was 10.2% for sword ferns within 15 ft of a tree or log. In contrast, the survival rate was 2.3% for sword ferns further than 15 ft from a tree or log... the odds of a fern surviving are 4.8 times greater if it is located within 15 ft of a tree or log. 

Based on these findings, management recommendations are to:

• Maintain or increase coarse woody debris and mature trees in natural areas
  susceptible to sword fern die-offs
• Prioritize restoration planting within 10 ft of CWD or mature trees

All preliminary data, subsequent revisions, R scripts and figures are available on github . 

First sign of natural regeneration at Seward Park's Ground Zero

Three fringecup plants (Tellima grandiflora if I am not mistaken) have popped up close to each other near the western edge of Seward Park's ground zero.   This is the first regeneration I have seen in the five years since the dominant sword fern community died in this quarter acre.   Here is one of the three. 

Seattle Times Pacific NW article on the Die-off

Seattle Times journalist Sandi Doughton and photographer Erika Schultz have published a magnificent article on the regional sword fern die-off.  Their grasp of the science, the historical context, the social interactions, the politics and complexity of grassroots activism - is, in so many ways, skillful, on point, and insightful.    They tell our story better than we ever could.

Regional Die-off Map (updated March 31 2019 and December 1st 2019)

(click on map to view the interactive version)

Includes 14 sites carefully assayed in the summer of 2019
(1 December 2019)

Better use of color, older data (31 March 2019)

Tim Billo's Presentation to the Washington Native Plant Society, January 3rd 2019

Tim, assisted by Kramer Canup, gave a masterful and comprehensive report on the regional die-off last Thursday.   Here are his slides - accompanied by extensive notes. 

Get the pdf.