Acadia National Park Update: Using transplant gardens to investigate climate change.

Caitlin McDonough MacKenzie

Greetings from Maine!

The view from a mountain transect, Acadia National Park

In Acadia National Park, we are investigating how climate change, and specifically warming spring temperatures, affect flowering times, and possibly the population sizes, of wildflower species.  We are currently monitoring flowering times along  transects that run up and down the slopes of three mountains, including Cadillac Mountain.  On the southern ridge of Cadillac, the transect begins in Northern hardwood forests and climbs through a pitch pine-jack pine community to open granite dotted with shrubby subalpine species.  A hiker starting out in a T-shirt will soon pull long-sleeved layers from her pack she ascends into the increasingly cool and windy microclimate above treeline.

A white Rhodora flower on Sargent Mountain,  May 28, 2013

Later this year we will use a common garden experiment to explore the relationship between temperature and flowering times.  To this end, we will create a series of transplant gardens at elevations from sea level through the summit of Mt Cadillac (1500’) using widely distributed species such as Rhodora and Low bush blueberry.  Each garden will be filled with transplants from the different elevations in Acadia, as well as plants of the same species from Concord.  In these elevation-created microclimates, we can test the roles of local spring temperatures versus the original home of each plant species in controlling its leaf out and flowering dates.  For a certain species, such as Rhodora, if all the plants in a garden bloom at the same date, regardless of their original source, then temperature is a more important factor than where the plant came from and its genetic characteristics.  But, if there is a difference among flowering dates of a particular species within a garden depending on where the plant came from, perhaps populations at different elevations (or different locations, such as Concord) have genetically adapted their flowering response in relation to local conditions.  We’re looking forward to using the common garden approach to dig into these questions on the interaction of climate change, temperature, flowering times, and local adaptation.

When you are in Acadia, please join me for a hike up the mountains!