<rking in the Arb during the New Student Week freshman service project, several 2015ers asked me why we were getting rid of buckthorn. I answered that there are many reasons why we remove buckthorn—among them that buckthorn dominates forest undergrowth, preventing native trees and wildflowers from taking seed. Plants provide energy for higher trophic levels of an ecosystem and a homogeneous plant community makes for less diverse animal communities. In short, buckthorn doesn’t just change the appearance of a forest, it spells doom for parts of our forest ecosystem that give it its distinctive character and unique species composition.
The answer to the common New Student Week question about buckthorn is couched in a broader question about restoration: Why do we engage in ecosystem restoration at all? While the Arb has a long history with restoration, the scale of restorative practices in the Arb increased dramatically in the last two decades as farmland was converted back into prairie and buckthorn removal advanced in earnest. Is the human hand still necessary in reviving this landscape?
The abbreviated response is that the land could not recover ecosystem functions without human intervention. Farmland left fallow will not recover prairie vegetation because the seeds of prairie plants are as scarce across the landscape as farmland is ubiquitous. Prairie plants are also subject to competition from invasive species that arrived and thrived here because of the agro-ecosystem.
Of course, the land will never recover to pre-settlement conditions—even with human intervention—because it has been irreparably altered by the totality of intensive agriculture in this region. But a high-diversity prairie ecosystem ruled by frequent fire disturbance is an attainable goal.
Such an ecosystem provides nectar to pollinating insects at times when nectar might not otherwise be available, nesting habitat for avian predators of agricultural pests, water filtration for underground aquifers, and erosion prevention for our waterways.
Most significantly, the act of restoring Arboretum lands ties the Carleton community to the land, the seasons, and the natural community around us in a way that is important in a world increasingly without local ecological identities. There are few opportunities to develop a connection to the land that is founded upon care and labor, as there were in the days of smallholder agriculture. As we delve further into the 21st century, I believe we will revive our relationship to the land in new forms, with local habitat management becoming a pillar of community life.
Owen McMurtrey ’12, for the
Cole Student Naturalists