SU Garden Helps Biologists Test Hypotheses about Invasive Species, Climate Change

Jul 7, 2015

There’s a place on Syracuse University’s South Campus where biologists are trying to figure out how woody plants behave and work. 

SU Associate Professor of Biology Jason Fridley looks at some Elderberry at the SU research garden off Skytop Road on South Campus.
Credit Scott Willis / WAER News

   Associate Professor of Biology Jason Fridley opens the gate into a garden plot that looks more like overgrown brush under a shade cloth.  It’s actually an outdoor lab for native and non-native plants.

 "Before I started this garden and played a hunch that ended up being wrong, it turns out the way I was wrong was far more interesting than if I been right."

Fridley’s hunch was based on observations in North Carolina where he was earning his graduate degree.

"Most of the natives leaf out in the spring around April, maybe a month or so before things get active here [in Central New York].  But there was this group of plants like multiflora rose from east Asia that a month or month and a half before anything else would get green, was deep green, doing its thing.  I thought, surely someone has looked into what's going on here.  Why do the invaders seem to have this really early phenology, the timing of when they leaf out in the spring."

So, Fridley and his colleagues assembled about 100 species of woody plants in the SU garden, half native, half non-native, to try and answer the question:  How can invasive species get into our forests, and seemingly get a head start on their native cousins?

"In general, do the non-natives leaf out earlier.  Turns out, the opposite is true.  There is no general pattern of the invaders leafing out."

 

Dozens of blue plastic kiddie pools are part of another experiment in the SU garden on south campus.
Credit Scott Willis / WAER News

  Fridley says there are certainly some, like garlic mustard and honeysuckle.  But there are also a whole range of natives that green up early, too, like Elderberry.   He says, though, their research has also found the invasives do stay greener longer, into the fall when natives are fading. 

Fridley says they found out it’s related to climate change and the ice age here versus east Asia.

"We had the most extreme ice age environment in the world.  Eastern North America was hammered about 20 times from these extreme cold events over the last two million years.  A number of species went extinct.  It was like this big sieve, where only the hardiest individuals made it through to today.  Probably the ones that made it through were the ones that had these really constricted growing seasons.  The same process never happened in east Asia.  

A tiny pine tree marked by a flag grows in a collar within one of the kiddie pools.
Credit Scott Willis / WAER News

  Fridley says this shows past climate change is as much a determinant of what happens today as the current climate change will impact the future.  But Fridley says that’s not the only experiment taking place in the garden.

"You see there's 70 kiddie pools.  You might be interested in what those eyesores are."

The small blue pools are filled with tree seedlings that make up the northern hub of a network of six duplicate experiments that extend to Florida.  Fridley says each hub is using different soils and species in different climates to try and understand how fields develop into forests.

"Turns out if you live south of the Mason-Dixon line, the field turns into a forest in about 10 years. You get a pine forest.  If you do that here, you cannot touch it for a century, and it's still a field, a field of beautiful goldenrod for as far as the eye can see.  That's been a conundrum for about 50 years, people wondering is that a climate thing, is it something about a colder winter preventing the woodys from establishing?" 

A black cherry tree seedling pops out of its collar.
Credit Scott Willis / WAER News

   

Fridley says they’re not sure yet.  He hopes their continued research will answer that and many other questions about the wild, woody plants growing in a plot on SU's South Campus.