Sand Dune Fungi

If you are at all familiar with PEI’s famous sand dunes, you likely understand the importance of Marram Grass (Ammophila breviligulata) in both building dunes and holding them together (more info here: https://www.pei-untamed.com/post/post-fiona-sand-dunes). But most people are unaware of dune fungi, which are equally essential to our Island’s dunes! 

Photo 1: Earthstar (Astraeus smithii) on a PEI dune.

Fungi are more closely related to animals than they are to plants, and in my six years of post-secondary education they were rarely mentioned. I studied botany and ecology, and later did research in PEI dune habitats and the only sand dune fungus that was ever discussed was Earthstar (Astraeus smithii, Photo 1.  More info here: https://www.pei-untamed.com/post/earthstar-fungi). That’s a shame, because dunes are home to a far greater diversity of fungi, and they are integral parts of this ecosystem.

Life on a sand dune isn’t easy. Temperatures are blazing hot in summer and bitterly cold in winter; freshwater is scarce while salt spray is abundant; and pure sand is low in organic matter and essential nutrients. This is not a recipe for a botanical paradise, yet certain plants thrive here. Usually, the plants’ own adaptations are credited for this: Marram Grass can handle salt spray and loves to be buried in sand, for example. That’s true, but only part of the story. The success of many dunes species is also due to the presence of mycorrhizal fungi.

Mycorrhizal fungi form relationships with the roots of nearby plants. The growth of young Marram Grass is limited by the availably of nitrogen and phosphorous; seedlings that can access more of these nutrients are more successful. Dune fungi capture nitrogen and phosphorus from sea spray – as well as washed up seaweeds, eelgrass, and other organic debris – and make it available to dune plants. In exchange, the fungi take some of the carbohydrates (sugars) that the grass makes via photosynthesis.  Not all mycorrhizal associations are mutually beneficial, but those in sand dunes seem to be.

Some researchers believe that these fungi don’t just help Marram Grass succeed, they are essential at certain stages of the plant’s growth. This fungal network is also able to collect and hold sand grains and so may contribute directly to sand dune stabilization. So, while Marram Grass gets all the credit, our dunes exist because of the interaction of water, wind, plants, and fungi.  How cool is that? 

Photo 2: Hygrocybe jackmanii on a PEI dune. This fungus was first discovered in Labrador in 2015, and has since been found in a couple of PEI locations. Photo by Ken Sanderson, used with permission.

These mycorrhizal fungi aren’t only ecologically important, they are also beautiful. PEI is on the frontlines of research into understanding the diversity of dune fungi with a multi-year research project being led by Ken Sanderson and Nature PEI. One of my favourites is a bright Waxcap (Hygrocybe jackmanii), first found in 2015 in Labrador and now known from a couple of locations in eastern PEI (Photo 2 by Ken Sanderson, used with permission). 

Photo 3: Dune Cup (Peziza ammophila) on a PEI dune. I prefer the alternative common name of Sand Tulip. Photo by Ken Sanderson, used with permission.

Dune Cup (Peziza ammophila, Photo 3 by Ken Sanderson, used with permission) is known in Dutch as ‘sand tulip’ which fits this beauty perfectly. Unlike the Waxcap, Dune Cup is a cosmopolitan species known from North and South America, Europe, Asia, Africa, and Australia.  It’s been found in a number of places along PEI’s north shore. 

Photo 4: Scleroderma septentrionale on a PEI dune. This fungus has 'legs'! (See Photo 5).

Being new to the world of dune fungi, I was intrigued to find a puffball growing in pure sand (Photo 4).  Intrigue grew to amazement when I saw the alien-like structure hidden beneath the sand (Photo 5 by Ken Sanderson, used with permission)!  This is Scleroderma septentrionale, known from eastern North America (with a few locations in Europe) and found in a couple of locations in eastern PEI.

Photo 5: The root-like rhizomorphs of Scleroderma septentrionale give it a decidely alien-like appearance! Photo by Ken Sanderson, used with permission.

These are just a few of the dozens of species of sand dune fungi found on PEI to date, and more continue to be discovered each year. You can learn more about these important but understudied fungi online (https://www.mushroomsofpei.ca/dunes.html) and at an upcoming presentation by Ken Sanderson, hosted by Nature PEI: Tuesday, 2 April 2024 at 7:30 pm at the Carriage House (2 Kent Street, Charlottetown, PEI).  Admission is free.

Dune fungi are beautiful, important, and amazing parts of PEI untamed!