A recap of the UES Spring Invasives Workshop
This past Sunday, April 6, 2014, nearly forty enthusiastic volunteers attended the Spring Invasives Workshop in Lower Frick Park offered by NMRWA and the Pittsburgh Parks Conservancy. It was a beautiful, sunny day, perfect for Jake Baechle, Volunteer Coordinator for the Parks Conservancy, and Paul Yanulavich, Urban EcoSteward Coordinator and Arborist for NMRWA, to talk about the Urban EcoSteward program and the importance of invasive plant removal and its connection to biodiversity.
For example, did you know that many plants from the nursery that people use in their gardens are specifically bred to be pest-free? Unfortunately, many of these plants find their way into Pittsburgh’s parks, where they have an unfair advantage over native plants.
While these invasive, pest-free plants are problematic for numerous reasons, one big one is that they affect the reproduction and survival of butterflies and moths. Butterflies and moths are not only unable to eat these plants, but they also are unable to lay their eggs on them, since they will ultimately need to be eaten by the young caterpillars.
One example of note is the monarch butterfly. Monarch butterflies’ main food source are native milkweed plants in the US & Mexico. Milkweed is the only plant Monarchs will lay their eggs on, which unfortunately is vanishing at a rapid rate, particularly in the Great Plains states along the Monarch butterfly’s migration route, due to increased use of herbicides. The effects on Monarch populations are alarming – at their peak in the 1990’s, Monarch butterflies occupied 45 acres of forest in the Mexican mountains; this past year they covered only 1.65 acres!
This lack of food and reproductive space for Monarchs as well as numerous other butterfly and moth species in turn affects bird populations. Adult birds can eat the berries of invasive plants, but their babies can only eat the soft butterfly and moth larvae usually found on the native plants these invasives are replacing.
Not all is gloom and doom, however. As participants at Sunday’s workshop learned, we can slow the rate of extinction and boost biodiversity and the food web by planting native plants, like milkweed, in our own backyards (and in the parks), and by removing the invasives that are taking their place.
Although not many plants (native or invasive) were coming up quite yet because of the late arrival of Spring, the group did manage to find plenty of emerging goutweed, garlic mustard, and mugwort plants to remove, and, as always, plenty of vines to cut away from our beautiful, native trees.
Thanks to all the Urban EcoStewards and other volunteers who helped to make the day a success, and to Jake Baechle and Pittsburgh Parks Conservancy Naturalist Mike Cornell for their knowledge, leadership, and insight.