Page 172 - Mapping the Nation: Taking Climate Action

171 Unused areas, including highway medians, are prime places for habitat to improve the prospects of pollinators. lay eggs, and later caterpillars transform into butterflies. Then in the fall, a fourth "super generation" is born that makes the whole journey south again where they overwinter. "The super generation lives longer and travels farther than the previous generations," Caldwell said. "If it's born in southern Canada, the journey could be close to 3,000 miles." This longest-journey generation gets a lot of attention and concern, because a lot of factors lead to these monarchs' success and survival. Climate change has become an increasing factor for the spring populations. "When they're heading north from overwintering in Mexico, they normally stop in Texas and lay their eggs there," Johnston said. "In a warmer year, they go right past Texas, and it puts them up north too early when there isn't enough milkweed yet, and a spring ice or snowstorm can wipe out big portions of the population." It is estimated that five times more milkweed is needed to support existing monarch migrations. That's why Johnston and colleagues conducted a study to document where milkweed exists and determine where more should be planted. "Monarchs have to lay their eggs on milkweed because it's the only plant the caterpillars will eat," Johnston said. "Ideally, milkweed should be mixed with other native plants not only to provide additional nectar resources but also to provide cover so the monarch caterpillars can keep hidden from predators." The milkweed habitat research led to the creation of GIS- based tools and planning guidance, which help cities and other landowners decide where to expand the planting of milkweed and other pollinator habitat measures. "The idea of unmanaged nature is becoming less and less viable," Caldwell said. "We have to intentionally create natural areas and take into account climate change to know where we are going to need this habitat 10, 20, and 30 years down the road." Proactive planting is part of future-proofing practices. "Some land managers like to source their prairie seeds further south where plants are already tolerating hotter weather," Johnston said. "That way, they're getting plants that are a little more adapted already to an environment that's getting hotter and hotter." Improving Practices and Anticipating Regulations The desire to improve pollinator habitat has caused many members of the Rights-of-Way as Habitat Working Group to reexamine vegetation management practices that are costly and labor-intensive. Regularly, utilities must survey and trim any trees that might fall on a transmission line during a high-wind or ice storm, and railway and roadway managers similarly must provide a safeguard against trees and large shrubs that may halt mobility or block visibility. What many land managers are finding is that they can save money while improving wildlife habitat. "Our members have begun applying the practices of integrated vegetation management, including the use of targeted herbicides, timed mowing, brush removal, and planting low-growing shrubs and broadleaf vegetation that outcompetes the trees that are problematic," Caldwell said.