I didn’t set out to study how endangered
ecosystems respond to catastrophic hurricanes, but then I woke up on
September 10th 2017 and this was happening.
[TV] Hurricane Irma devouring Florida tonight… has made landfall in the Florida
Keys… these storm chasers clocking speeds… I spent all morning refreshing
the radar on my phone because the eastern eye wall of Hurricane Irma was
on top of Big Pine Key where I had been working for six years and had set up an
experiment two years before. The experiment I set up was to study
populations of this plant, Croton linearis, because it’s the sole host
plant for two endanger butterflies: Bartram’s scrub hairstreak and Florida
leaf wings. These species only live in pine Rockland forests which are only
found in a narrow strip of high elevation land in South Florida.
Historically, these forests burn really regularly and Croton relies on that fire
to maintain the open structure of the forest.
Now, that habitat is surrounded by neighborhoods and strip malls and that
makes it really hard to put fire on the ground. In the last half-century Croton
populations have crashed in places without fire and that’s really
devastating for these two butterflies that rely on this plant. So, my original
experiment was to test whether we could use mechanical clearing as a surrogate
for prescribed fire and still have positive benefits for the plants and the
butterflies. So, mechanical clearing is like fire, in
that it opens up the understory, but it leaves behind this layer of mulch that
new plants have to push up through to access sunlight. My original intent was to
compare mechanically cleared forest to forests that were unmanaged but then
Hurricane Irma hit it all. So here’s what my field sites looked like before the
hurricane and then after. During Irma the whole Island was over washed with
storm surge and really strong winds blew debris out of the trees and all over
everything. When I went back and collected data after the storm, now my
data could tell us about how the management that we’ve done prior to the
storm interacted with the effects of the hurricane. So, when we look at all of our
data across all of our sites, the storm was bad for Croton.
But the worst place to be was in unmanaged sites. We had higher
survival rates in places that had been previously mechanically cleared and the
highest survival rates were in places that have been burned. It can get a
little depressing thinking about whether or not the decisions that we make now
actually matter in the face of a change in climate, but I think it’s really
important that we’re doing these best management practices, like using
prescribed fire on a regular basis, to maintain current populations and species.
And then not only does that maintain them now but it gives them a chance to
weather big catastrophic storms like hurricanes