Better understanding the potential importance of florida roadside breeding habitat for the monarch

Abstract

The North American monarch butterfly (Danaus plexippus) population has declined significantly over the past two decades. Among the many other factors, loss of breeding habitat has been implicated as a potential leading driver. In response, wildlife agencies and conservation practitioners have made a strong push to restore and conserve milkweeds on both wild and managed landscapes including agricultural lands as well as transportation and utility rights-of-way. Roadsides in particular have been emphasized as a targeted landscape for monarch habitat restoration. While much attention has been focused on habitat in California, along the I-35 corridor from Texas to Minnesota, and more broadly across the agricultural Midwest, research on the occurrence of roadside breeding habitat and the development of best vegetative management practices conducted in the Deep South has been limited. We sampled roadside verges in north-central Florida for the presence of two early season milkweed species, that are particularly important for early season monarch recolonization, Asclepias tuberosa and Asclepias humistrata. Our findings suggest that roadsides harbor extensive populations of the target milkweeds with the vast majority of plants occurring on the back slope of the verge. Alterations to current roadside mowing frequency and scope are needed to effectively conserve these populations and ensure that they are available for use by the monarch.