The shy and elusive Martes martes, or pine marten. (Photo: Dani Kropivnik, Wikimedia Commons)
Some species need the forest in order to survive. In the Basque country of Spain, pine martens depend on large swaths of old growth forest for food and to hide from predators. Producer Ari Daniel Shapiro joined a pair of scientists as they searched the forest floor for evidence of the elusive marten.
GELLERMAN: Animals leave behind little clues to their past and to their future. Reporter Ari Daniel Shapiro traveled to northern Spain recently, where he met a couple of scientific sleuths who make a living following their noses as detectives tracking down the clues animals leave behind.
[WALKING AND LAUGHING SOUNDS]
SHAPIRO: It’s not often you get to see two grown men get excited over finding a pile of feces on the ground. But a few months ago, I saw exactly that. I was in the wet forested mountains of northern Spain, in the Basque country.
The two men were Javier López de Luzuriaga and Aritz Gonzalez, and they study martens; small, bushy, large-pawed carnivores. They look a bit like weasels, and they’re really elusive. Luzuriaga, a freelance field assistant, has been working with martens for four years, and he says he’s seen the animals just twice.
LUZURIAGA: The first time I was in this mountains, I heard some noise. The marten was walking two meters from me.
SHAPIRO: What did that feel like?
LUZURIAGA: It was… impresionante, ¿no?
SHAPIRO: Exciting because most of the time, all these two get to see is evidence the martens have left behind. Like the feces lying on the muddy trail. Gonzalez, a zoologist at the University of the Basque Country, squats down to get a better look.
GONZALEZ: Okay, this is a very good quality sample, okay, so we are going to take the sample for our DNA analysis, Okay?
SHAPIRO: Gonzalez uses a twig to gently pack some of the feces into a couple of small tubes. What he really wants are the cells on and in the feces, cells sloughed off from the gut of the defecating animal. Even though he’s pretty sure the feces were deposited by a marten, Gonzalez doesn’t know whether they came from a pine marten, Martes martes, or a stone marten, Martes foina. Back in the lab, the DNA in these cells will tell Gonzalez which species of marten was responsible.
SHAPIRO: And that distinction, knowing which type of marten is where, is at the center of the puzzle Gonzalez is trying to unravel out here. He’s searching for pine martens in the forested areas of the Basque country.
GONZALEZ: Usually when we have this kind of good quality forest, usually the pine marten has an advantage to survive over the stone marten.
SHAPIRO: Pine martens depend on large swaths of old forest. The trees give the animals protection from predators, they’re perfect for creating dens, and the forest provides the habitat for the small mammals that pine martens eat.
GONZALEZ: But not all forested areas of Northern Spain are able to have pine marten populations.
SHAPIRO: The old forests here have been fragmented by roads and towns, interrupting the continuous stretches of tree-lined slopes. The DNA work has taught Gonzalez that pine martens are in a delicate situation, the pockets of remaining animals have grown genetically isolated from one another. Stone martens, however, are doing just fine.
GONZALEZ: The stone marten is able to adapt to many, many different conditions, to open fields, even in urban areas, in big cities.
SHAPIRO: Stone martens thrive in areas markedly transformed by humans. They can tolerate warmer weather as well, so they can be found clear down to the Mediterranean Sea. And the relative success of the stone versus pine martens says something about the altered versus natural environment.
GONZALEZ: The pine martens, they need the forest to survive, so if we conserve pine martens, we are conserving many, many other species.
SHAPIRO: Chief among those species is Quercus petraea, or the sessile oak tree.
SHAPIRO: Gonzalez walks briskly to show me one of his favorite spots. At last, we come upon an enormous sessile oak. (Wow, this is so beautiful.) It’s 300, maybe 400 years old. The thick, mossy trunk surges up from the ground, and a web of branches, like a tangle of hair, decorate the top half of the tree. Gonzalez leads me to an opening near the ground, and we both enter a cavity at the base of the trunk.
[SOUNDS OF CLIMBING INTO TREE]
SHAPIRO: How big can you stretch your arms out?
GONZALEZ: So, we can put my right hand on one side and with left hand, maybe, two meters something like that.
SHAPIRO: But basically, it’s the distance from, if you stretch your arms out to either side.
GONZALEZ: Yeah, like that.
SHAPIRO: The tree’s big enough to fit 14 people. They tried it once. The grooves of the inside of the trunk curl upwards like a helix.
GONZALEZ: Of course, we have not so many of huge oaks because we have been cutting them many years ago, but we have some survivors of the human activity like this one. I think that for pine martens, those trees are their home. So, of course, I think to maintain pine martens, estamos obligados, we are…?
GONZALEZ: Obligated to maintain this kind of forest.
SHAPIRO: Gonzalez’s first name, Aritz, it means “oak” in Euskara, the Basque language. His sense of obligation to protect the trees of this forest, the trees that are his namesake, is rooted in a idea that these trees are living history.
GONZALEZ: Yes, it’s historia viviente – living history.
SHAPRIO: This oak tree has survived centuries of human exploit, serving as a home for pine martens for just as long. Gonzalez is a strong advocate for protecting the integrity of these trees and of the forest, managing it in a way that allows pine martens to thrive right alongside stone martens, just as they used to. For Living on Earth, I’m Ari Daniel Shapiro.
GELERMAN: Our story on pine and stone martens is part of the series, One Species at a Time, produced by Atlantic Public Media, with support from the Encyclopedia of Life.
To see some cool photos from Ari's trip to the Basque region, follow the trail to our website loe dot org - or check out our Facebook page - it's PRI's Living on Earth.
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