Forests Under Contruction

Environmental & Science Education, STEM, Global Change, Global Climate Change, Sustainability, Wildlife, Nature, Nature of Science, History of Science

Ed Hessler

Forests as Brandon Keim, writing for the New York Times, notes come into being and growing from "creatures whose labor makes the forest possible -- the multitudes of microorganisms and invertebrates involved in maintaining that soil, and the animals responsible for delivering seeds too heavy to be wind-borne to the places where they will sprout" and thrive.

He continues "If one is interested in the future of a fores -- which  tree species will thrive and which will diminish or whether those threatened by a fast-changing climate will successfully migrate to newly hospitable lands -- one should look to these seed-dispersing animals." He discusses the research of Ivy Yen, "a doctoral student in the lab of Alessio Mortelliti, a wildlife ecologist" at the University of Maine who has a particular interest in which he joins animal personality and seed dispersal.

Animal personality is judged by tests their level of boldness and shyness - a continuum of possibilities. Yen, who does her research at Penobscot Experimental Forest paints acorns with colored bands, indicating oak species, both the newly arrived and those who have been there for centuries. The mice or voles have been tested and injected with a microsensor. As "an acorn-laden tray" is approached, "a sensor reads their microchip, identifying the animal; a motion-activated  camera captures the moment, recording which nut they took." Yen places "more than 1,800 acorns" "over the course of this season." 

Five trays, each about 100 feet apart are set out, around which Yen scatters "a nontoxic fluorescent powder that temporarily adheres to the feet of visitors."  When she returns "before dawn, equipped with an ultraviolet flashlight  under which the powder fluoresced, small constellations of footprints (surround) each tray and (trail) off into the darkness. Yen follows these, one-by-one with some trails petering out as the powder is is worn-away, "others (end) in a cache -- a hollow beneath a root, a decaying stump, a hole dug into the earth and carefully covered back up." Each of these spots is marked with a small orange flag.

The disposition of the acorns is documented and some are found intact while others are consumed (the painted shell fragments allow Yen to identify the species. One finding:  The data from sensors and camera recordings "would later show that much of the gathering was performed by one notably industrious deer mouse known to the researchers ad 982091062973077, a 13-gram male trapped in late September and revealed by tests to be fairly shy, although with a cautiously exploratory streak." Personality appears to influence the likelihood to cache certain kinds of nuts.

Asked to define the practical implications of his research, Mortelliti said, “'Preserve a diversity of personalities.' There’s no one ideal personality; rather, different individuals perform different roles. Depending on circumstance — drought, natural disturbances, fluctuations in predator populations — different personality types may come to the fore. These nuanced dynamics don’t preclude timber-cutting, Alison Brehm, Mortellit's first Ph.D. student, said, but they do argue for taking care. Also see here for Brehm's publications. She is currently a PostDoc, University of Wisconsin-Madison.

“If you have to manage a landscape, you don’t want to manage it all the same way,” Brehm said. “You want to manage different parts differently so that you have a heterogeneous landscape.” Techniques can be used that maintain a variety of tree species, ages and sizes, attempting to mimic what would happen naturally.

"Much remains unstudied, Mortelliti noted. Measures of shyness and boldness are not the entirety of animal personality; they’re just relatively well-characterized and easy to measure in the field. Oaks aside, hundreds of other plant species are shifting their ranges, each following their own animal-mediated trajectory.

I close with an observation from Yen. "'I'm only looking at two species at night. It's a very small snapshot of what is happening.' A full picture may not emerge for decades but the outlines are already clear: It takes a lot of personalities to raise a forest." 

Brandon Keim's reporting may be read in full at the Seattle Times and, of course in the New York Times - print and electronic if you are a subscriber. 

And if you are interested in how measures of boldness and shyness are made this scientific paper includes several that were used in determining these personality traits in a field study of free-ranging lizards. 

This publication on small animal habitat on the Penobscot Experimental Forest includes a short YouTube video (4 m 56 s) - Small Mammals, big Personalities from the University of Maine. It includes a description of the tests, comments from researchers and a discussion of the forest experimental set-up in the field.