Lupine Propagation Threatens Nature Preserve: ‘We want to keep our Icelandic flora’

Lupines may be beautiful, but they’re also an invasive species. RÚV reports that lupine propagation around the Krossanesborgir nature preserve near Akureyri, North Iceland, may well be having a significant—and negative—impact on indigenous plant and animal life.

‘The point of no return’

As Egill Bjarnason explained in his 2018 New York Times article about the ongoing lupine controversy in Iceland, “[t]he blue Nootka lupine are native to North America and a familiar sight in flower gardens there. They have spread wildly in Iceland since their introduction in the late 1970s to halt soil erosion.”

But while the plant does have positive attributes (it’s a free ‘fertilizer factory,’ as Egill explains), and while tourists and even many Icelanders love the plant for its characteristic violet-blue blossoms, it spreads much more easily than originally anticipated and, among other places, has made significant inroads in Iceland’s central highlands, where originally, it was thought it wouldn’t be able to survive.

Locals used to be encouraged to spread the seeds—some villages would even distribute free scoopfuls of seeds at gas stations. But in spring 2018, the Soil Conservation Service of Iceland stopped its seed distribution program after 42 years, with director Arni Bragason remarking of the plant and its impact on the local environment, “We’re at the point of no return.”

Timing is everything

Krossanesborgir was designated a nature preserve in 2004 in order to protect its diverse plant and bird life. But with the encroachment of lupine in the area, this this ecosystem is now endangered, says Jón Ingi Cæsarsson, the former chair of the Akureyri organizational committee.

“All of the undergrowth and moor vegetation is going to vanish and instead, we’ll have these tall, beautiful plants. But that’s not something we want—we want to keep our Icelandic flora, especially in these nature preserves,” he said.

Local officials are aware of the lupine situation and the plant is cut back on a regular basis, including in Krossanesborgir, says Rút Jónsdóttir, Akureyri divisional manager.

“We usually begin [cutting back lupines] around June 15-20,” she explained. Working out the right time to start the mowing is difficult, she continued: too early, and birds will still be nesting in the area; too late, and the lupines will already bloomed. (Timing is everything when it comes to lupine eradication, explains Egill. “Killing the plant is a three- to five-year process that involves cutting them back at the peak of the bloom, when the plant is putting its energies into the flowers and the roots are correspondingly weakest. Mowing down the plants has proved more effective than herbicides.”)

‘It will take off if we don’t rein it in’

The lupine has not yet made significant inroads within Krossanesborgir, but Jón Ingi is nevertheless concerned that it may only be a matter of time. Roughly 30 species of birds nest in the area, he explained, making the area particularly important from a preservation standpoint.

“The lupine is here and is lying in wait and will take off if we rein it in. We’ve seen what happened on Hrísey [a small island in Eyjafjörður, north of Akyreyri, known for its bird life]. The number of breeding birds will most definitely decrease [in Krossanesborgir], just like happened there.”

Birch Trees Beset by Bugs

Scolioneura betuleti sawfly larvae in birch leaf.

Birch trees in the Reykjavík capital area are struggling following two waves of pests this spring and summer. While the trees made a comeback after moth larvae ate their way through new growth in the spring, they were soon beset by another hungry creature. Sawfly larvae, first spotted in Iceland in 2017, have done a number on local birch this summer, leaving behind brown leaves on many trees in the capital area.

“Many have noticed that the birch trees in our gardens are not doing well,” a press release from the Icelandic Institute of Natural History reads. According to the press release, Eriocrania unimaculella, moth larvae that mine birch leaves, ravaged the trees this spring. “In the short term, the trees managed to regain their foliage,” the release continues, “but a new pest has emerged which is greying the new leaves.”

The new pest is the larvae of the Scolioneura betuleti sawfly. The larvae was first spotted in Iceland in 2017, though it is not known when it first arrived in the country. Experts had noticed, however, damage to birch trees in late summer for several years prior which was similar to moth larvae damage in the spring. It was hypothesised that a second generation of moth larvae was to blame, but it has now been established that sawfly larvae is the culprit.

Scolioneura betuleti larvae behave similarly to Eriocrania unimaculella larvae, though they are not related. The sawfly lays its eggs in birch leaves in midsummer. Larvae live in and eat the leaf tissue, which is known as “mining” the leaves. The pests’ one-two punch can make it difficult for birch to grow healthy foliage all summer, “which will probably reduce the growth of the trees, seed ripening, and necessary preparation for the winter months.”

According to experts, green alder shrubs (Alnus viridis), a relative of birch common in Reykjavík gardens, may also be at risk from the Scolioneura betuleti larvae.