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.

Overview

New Posts (please scroll down):

December 2018: request for research proposals, site visit by LSU plant pathologist

October 2018: two experiments, possible insight into mechanisms of spread

Since 2014 we have been observing and attempting to understand a dramatic die-off of the dominant understory sword fern species, Polystichum munitum, in the 120-acre old growth "Magnificent Forest" in Seattle's Seward Park. 

Please add your own observations at our iNaturalist project.

Extensive lab and field work, consultations with fern experts throughout the US, and recent reports of die-off from elsewhere in the Puget Lowlands of Washington state (see annotated regional map), lead us to conclude with considerable confidence: 

• The die-off is caused by an (as yet unidentified) pathogen 
• Climate change may be a contributing factor, but until the proximal cause of the die-off is determined, the role of climate change can not be known.  
• Drought is probably not a cause (see rainfall records below).
• Is unprecedented, not part of the P.munitum life cycle, in which ferns colonize open ground, do not reproduce under a closed canopy, with individual plants living for hundreds of years.
• Holds implications for the forest at Seward Park, and for other forests in the region.

Some selected blog entries

• A Lazarus Fern? (March 2018)
• Port Ludlow die-off, some recovery: 2010 - present
• Experimental Plantings at and near Ground Zero (March 2018)
• Hypotheses

• Die-off reported from Snohomish County, Lord Hill Park (January 2018)
• Extensive die-off confirmed on Bainbridge Island and the NE tip of the Olympic Peninsula (December 2017)
• Narrative Essay - an overview
• Soil Analysis (June 2017)
• King 5 video (2 minutes, May 5th 2017)
• KUOW (27 july 2017)
• Sierra Magazine (August 2017) by Sarah DeWeerdt
• Seattle Precipitation Records (2012-2016, evidence against drought/die-off causality)

Contact: Paul Shannon, Forest Steward