Establishment of Additional Monarch Butterfly Host Plants at the Sand Hill Lakes Mitigation Bank David Clayton Environmental Scientist III David.Clayton@nwfwater.com Northwest Florida Water Management District 81 Water Management Drive, Havana, Florida 32333 Each year in February and March the monarch butterfly comes out of hibernation in Mexico and migrates north and east to start the next generation of butterflies. The yearly butterfly migration takes four generations to complete. Each adult butterfly only lives from two to six weeks. It is unclear how the multigenerational migration is inherited or how the butterflies know the route back to the same forest each year, a journey of thousands of miles to a forest reserve that covers 193,000 acres (56,259-hectares) in central Mexico. Recently, however, the migration has become imperiled. After steep and declines in the previous three years, the monarch now cover only 1.65 acres (0.67 hectares) in the pine and fir forests west of Mexico City, compared to more than 44.5 acres (18 hectares) in 1995. Milkweeds (Asclepias spp.) are the required host plants for the larval monarch butterfly (Danaus plexippus) and thus play a critical role in the monarch s life cycle. The loss of milkweed plants in the monarch s breeding range across the United States is thought to be a significant contributing factor to the decline of monarch butterflies observed in overwintering sites in Mexico. Agricultural intensification, development of rural lands, and the use of mowing and herbicides to control roadside vegetation have all reduced the abundance of milkweeds in the landscape. If the monarch butterfly population does not rebound it is expected that the migration of the species will end in the near future and the familiar butterfly may be absent from significant portions of its range. In an effort to increase the population of monarch butterflies, the North American Monarch Conservation Plan (published in 2008) recommends the planting of regionally appropriate native milkweed species. In the fall of 2014, the USFWS initiated a pilot program to establish additional populations of butterfly milkweed (Asclepias tuberosa) on conservation lands in the Florida Panhandle to help support the monarch butterfly population. Butterfly milkweed is an important larval host plants and nectar source for the monarch butterflies (Figure 1). In September of 2014, the NWFWMD was encouraged by Federal Highways and USFWS to apply for the pilot program due to the success of our FDOT restoration program. The site chosen to receive the additional plants is the Sand Hill Lakes Mitigation Bank (SHLMB) located in Washington County (Figure 2, 3). This site contains high quality sand hill habitat that many larval milkweed species prefer (Figure 4). Monarch butterflies are commonly observed at the SHLMB during the fall as they migrate south and as they migrate north in the spring (Figure 5). Enhancing the butterfly milkweed population at the SHLMB will support the monarch butterflies within the Florida Panhandle and could aide in the recovery of local populations. An outline of the project was submitted to Federal Highways and USFWS at the end of September 2014. With encouragement from the USFWS, a proposal was submitted. On December 17, 2014 the District was awarded $3,000 to establish an additional 3,250 butterfly milk weed plants at the Sand Hill Lakes Mitigation Bank (SHLMB). District staff will be the principle investigators and determine the planting locations. The
butterfly milkweed plants will be grown and planted by Southern Habitats. Southern Habitats is located in Madison Florida and specializes in growing native plants. Photos by David Clayton Figure 1. Butterfly milkweed (Sand Hill Lakes Mitigation Bank population)
Figure 2. Sand Hill Lakes Mitigation Bank Site Location Map
Figure 3. Sand Hill Lakes Mitigation Bank Boundary Map
Figure 4. Monarch butterfly at the SHLMB on a coastal plain honeycomb head flower Figure 5. Quality sand hill habitat at the SHLMB