It may sound like a new upscale restaurant or the name of the latest “new urbanism” housing complex in Madison. But it’s none of these, although it is of relatively new origin and is an unusual entity. The Mustard Grove (aka Marion Dunn Prairie) is probably a novel ecosystem. At any rate it certainly is a black walnut grove with a ground layer of introduced mustard species (Brassicaceae), including garlic mustard, Dame’s rocket and yellow rocket. The Brassicaceae (cabbage family) globally ranks among the top 50 most invasive plant families.
What is a novel ecosystem? Basically, it is a combination of plant and animal species that have not previously existed. According to Hobbs, Higgs, and Hall (2013) in their new book from Wiley-Blackwell, “Novel Ecosystems, Intervening in the New Ecological World Order”, novel ecosystems “are those systems that differ in composition and/or function from present and past systems as a consequence of changing species distributions, environmental alteration through climate and land use change . . .” (p. 4)
“Such systems can arise either from the cessation of past management practices or because of changes in mostly un-managed systems.” (Hobbs, Higgs, and Hall, 2013 p. 4). In this case the cessation of fire and ineffective pest species control probably played a role in the transformation of the former prairie into a novel ecosystem.
The Marion Dunn Prairie was a tall-grass prairie planting begun in 1982, done largely through the efforts of volunteers. From that time through 2004 the site was managed with regular prescribed prairie fires. But the gradual transformation of the site by black walnuts and mustard invasions and storm water management issues made prescribed fires after 2005 impractical.
But today, The Mustard Grove is probably a novel ecosystem, as opposed to being an historical prairie system that is within its normal range of variation. It is probably not a hybrid prairie system with a few non-native species intermixed with the usual prairie plants. According to Hobbs, et al. (2013) novel ecosystems such as The Mustard Grove have passed ecological thresholds of changes that render it extremely difficult, if not impossible, to return the system to its previous condition.
This irreversible condition presents a dilemma to restorationists whose goals are recreation of historic ecosystem conditions in this changing modern world. However, novel ecosystems raise important questions for restoration ecologists. For example, since novel ecosystems are relatively new we don’t know much about how they work, nor do we know what can a land manager can, or should, do about them. We don’t know the range of realistic and possible conservation goals for novel ecosystems. Will society learn to value novel ecosystems and what ecological, social and cultural restoration goals will be socially acceptable?