An evaluation of butterfly gardens as restoration tools using the monarch butterfly Danaus plexippus
Date
2012
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
As human influence continues to expand into natural areas, the ecological systems that support biodiversity and human populations are failing; most land has been transformed from functional habitat into unsustainable landscapes that suit current human needs. Residential areas are often managed to meet aesthetic and cultural norms, but wildlife gardening holds promise as an acceptable method for sharing human dominated landscapes with plants and animals. In particular, butterfly gardening with suitable host plants can attract breeding Lepidoptera to residential properties, and support higher trophic levels in the process. Despite the popularity of this movement, few studies have evaluated the usefulness of gardens to wildlife by measuring the fitness of multiple stadia of target insects. One study has shown that, if managed improperly, gardens could be ecological traps which are attractive as oviposition targets but support higher mortality, thereby lowering regional populations of the very organisms that they are intended to conserve. I studied the monophagous monarch butterfly Danaus plexippus L. and how it is affected by butterfly gardens containing its Asclepias host plants. I found increased oviposition on milkweed in gardens over milkweed in natural areas. There was no difference in total sub-adult survival between garden and natural sites, and differences in survival of eggs and larvae were not consistent through the two years of the study. It is likely that isolated patches of milkweed, as are often found in gardens, are more frequently encountered by ovipositing females, and larval mortality factors are density independent. These results suggest that butterfly gardens with milkweed may serve as source habitats for monarchs, and would thus be useful as a restoration tool for this specie.