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| Map of high-elevation in addition to alpine areas of northeastern United States, with locations of my master’s inquiry (White Mountains) in addition to PhD inquiry (Acadia National Park). The 3 major high-elevation paleoecological study sites inward the northeast are the Adirondacks, Mt Washington, in addition to Sargent Mountain Pond. Map created yesteryear Kevin Berend. |
An alpine masters in addition to a ridge transcend PhD
I’ve worked to a higher house treeline inward the northeast USA for over a decade. Both my master’s in addition to my PhD inquiry were grounded inward plant phenology — I spent many springs compiling detailed records on the timing of leafage out in addition to flowering. My perception of fourth dimension was brusk — the y axes of my figures were ‘day of year’. Change over fourth dimension was measured inward years, or inward the illustration of real long records, decades. There was an immediacy in addition to a precision to my fieldwork — I monitored for changes every few days to choose handgrip of each found correct every bit it bloomed. The plain sites were incredible: hiking my favorite mountains calendar week afterwards week, wearing out the treads on my trail runners on long treks across opened upwards granite ridges. There were bad days, to hold upwards certain — abrupt pelting storms, blisters, sunburns, dark wing bites, in addition to granola bar fatigue — but I loved beingness to a higher house treeline. My master’s locomote inward New Hampshire’s White Mountains and my PhD inquiry inward Acadia allowed me to pass long limit days inward these incredible alpine in addition to subalpine habitats each year. Climbing to my plain sites in addition to transects meant hiking through forests in addition to watching the maples in addition to beeches give agency to birches, firs, in addition to stunted spruces earlier emerging to a higher house the trees into a globe of cushion plants in addition to tiny tangled shrubs. Sitting dorsum against a summit cairn in addition to soaking inward the Sun spell clouds embrace the valley below inward a pillowy undercast is alongside my favorite experiences, in addition to throughout graduate schoolhouse I got to create this forenoon afterwards forenoon on peaks from Mt Washington to Sargent Mountain.
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| My in conclusion hike for PhD inquiry inward Acadia National Park, with my immature lady every bit my 'research assistant.' Photo credit: Mike MacKenzie. |
During my many hikes monitoring phenology, I oftentimes marveled at the alpine plants. Survival to a higher house treeline is impressive: the growing flavor is short, the air current in addition to H2O ice are intense, in addition to the soil is shallow in addition to poor. Alpine in addition to subalpine habitats are scattered across the highest peaks inward the U.S. northeast, similar picayune islands to a higher house the forest. In Acadia National Park, on the coast of Maine, the mountains are quite pocket-sized — alone 466 m on the summit of Cadillac — in addition to subalpine found communities persist at these depression elevations. The northeast’s alpine in addition to subalpine habitats choose been interpreted every bit post-glacial tundra relicts, the offset found communities to colonize this barren landscape every bit the Laurentide Ice Sheet retreated 15,000 years ago. As the climate warmed inward the Holocene, forests moved inward at lower elevations, in addition to alone the coldest microclimates continued to back upwards tundra plants. This is the explanation I recollect from college, in addition to from the seasons I worked inward environmental educational activity inward the White Mountains.
During my PhD inquiry inward Acadia, I started next Maine scientists on Twitter. I offset met Jacquelyn Gill when she was a novel faculty fellow member at the University of Maine. Our paths crossed online in addition to hence inward person, when she visited Acadia to give a speak on her paleoecological work. I recollect hollo for her for closed to paleo-insight into the low-elevation subalpine communities inward Acadia — why was I able to notice plants similar mount cranberry in addition to crowberry nearly 900 m below their elevation limit inward New Hampshire? She confirmed my retentivity that these were regarded every bit tundra relicts but noted that this was an untested assumption. Most paleoecological locomote inward the northeast is based on sediment cores from depression elevation ponds. Very picayune locomote has been done to a higher house treeline.
At depression elevations across the northeast, in addition to peculiarly southern New England, decades of inquiry based on pollen in addition to macrofossils from sediment cores break a dynamic mosaic of vegetation assemblages responding to postglacial climate modify over the yesteryear 14,000 years. Pollen in addition to found macrofossil records from Lakes of the Clouds, perched only to a higher house treeline on Mt Washington, propose that this site — the highest peak inward the northeast — maintained alpine vegetation throughout the Holocene. The Lakes of the Clouds inquiry has been cited every bit prove for the projected persistence of alpine habitat on Katahdin (Maine’s highest peak), though all state-listed threatened or endangered found species inward Maine associated with alpine habitats had medium or high vulnerability to climate modify inward the same report. I am aware of alone 1 other high elevation pollen tape from the region, a study of vegetation patterns inward the Adirondacks of New York. These Lakes of the Clouds in addition to Adirondacks studies are over 25 years onetime in addition to analyzed at temporal resolutions likewise coarse to capture responses to rapid warming events since deglaciation. With the available paleoecological data, it is impossible to know if the electrical flow distribution of alpine in addition to subalpine habitats inward the northeast — which comprise non only the highest elevations but are also scattered across isolated peaks in addition to low elevation coastal ridges — stand upwards for persistent refugia for tundra vegetation throughout the Holocene.
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| Collecting sediments at Sargent Mountain Pond with Jacquelyn Gill inward September 2017. |
Same place, dissimilar fourth dimension
After my conversations with Jacquelyn, I became slightly obsessed with the mystery of northeast alpine in addition to subalpine vegetation. During the in conclusion plain flavor of my PhD, I was even hence hiking my phenology monitoring transects, but I began to await at the mountains with a novel focus, in addition to my fourth dimension scale all of a abrupt unspooled from year-to-year shifts inward flowering to 1 hundred- or thousand-year shifts inward vegetation assemblages. In betwixt hikes on the ridges, I sat downwardly with Jacquelyn in addition to sketched out a proposal to study these paleoecological dynamics. I began to optic the kettle hole Sargent Mountain Pond that sat only below treeline on my transect hike downwardly the southward ridge of Sargent Mountain — I knew that researchers had collected sediment cores at that spot inward the past, but the pollen had never been worked upwards for the total Holocene. Towards the destination of a PhD, it’s mutual to think virtually the future. Somehow, at the destination of my PhD, I became immersed inward the deep past. I wrote a postdoc proposal to supply to Acadia National Park in addition to collect sediment cores. I would hold upwards hiking upwards Sargent Mountain 1 to a greater extent than fourth dimension — at 1 time with coring equipment, an inflatable kayak, in addition to a raft — but instead of studying this year’s flowers, I would hold upwards coring for prove of yesteryear found communities. Somehow, this postdoc has rushed yesteryear in addition to I’m already approaching the destination of my paleoecological fellowship. While I completed coring fieldwork in addition to began pollen in addition to macrofossil analysis, I piece of cake shepherded my dissertation chapters through peer review. Re-reading the proofs from my dissertation locomote brings me dorsum to my life earlier paleoecology in addition to reminds me of my offset encounters with the alpine plants I at 1 time search for inward my sediment cores.
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| Working on 1 of my sediment cores in Jacquelyn Gill's lab. Photo credit: Britte Heijink. |
Caitlin MacKenzie, Ph.D.
David H. Smith Postdoctoral Research Fellow, Climate Change Institute, University of Maine
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