Monarch butterflies are an iconic North American species; their migration event each year is an exceptional example of our natural heritage. Monarch butterflies travel from overwintering grounds in central Mexico and southern California northward through the U.S. each year, stopping on milkweed plants to lay eggs as they go. Milkweeds provide food for monarch larvae after they hatch; monarchs must find milkweeds to reproduce. In the fall—multiple generations later—they fly south, some traveling thousands of miles, back to the overwintering grounds from which their ancestors came.
The monarch butterfly migration is in peril. The population of monarchs has declined by 80% since 1996. If this trend continues, the population of monarchs will not be sufficient to complete the annual migration. To protect the monarch from this risk, scientists, policymakers and other stakeholders have agreed upon an overarching goal to increase the monarch population to 225 million butterflies by 2020.
Many factors are contributing to the dramatic decline in monarch population numbers. The adoption of glyphosate-tolerant crops and changing land uses have diminished the abundance of milkweed, which monarchs require to reproduce. The nectar plants on which adult monarch butterflies forage have also been impacted. In order to support a healthy monarch population, milkweed and nectar plant species must be restored and maintained—providing an opportunity for farmers, ranchers and land managers to participate in rejuvenating the habitat of this important icon of our national heritage.
The Monarch Habitat Exchange (Exchange) is an incentives-based program developed by Environmental Defense Fund (EDF) intended to promote restoration and protection of monarch habitat across the United States, particularly on agricultural lands and roadway corridors. The program supports farmers, ranchers and other land managers to create, enhance and manage monarch habitat. Participants can generate “credits” based on the quality of the habitat they produce. Chemical companies, seed companies, philanthropists and conservation organizations can purchase credits to fund monarch conservation and mitigate risks to monarch populations. As participants in the Exchange, landowners can make habitat conservation a part of their business portfolio.
The Monarch Habitat Quantification Tool (HQT) facilitates the Exchange by evaluating habitat suitability and thus informing credit awards assigned to landowners. The HQT is a science-based approach to assessing habitat suitability and the resulting conservation outcomes for monarchs, based on empirical data and expert opinion. The HQT informs the valuation of monarch habitat within the context of the Exchange, tracks changes to meaningful habitat variables through time, and reports progress towards regional program goals.
Environmental Incentives developed the HQT in partnership with EDF and the Monarch Lab at the University of Minnesota. The HQT is used by the Exchange to evaluate monarch habitat restoration projects. The HQT is intended for farmers, ranchers, roadside and rights-of-way managers, natural areas managers, and gardeners interested in creating and maintaining monarch habitat. It has already been used on thousands of acres, and is helping to provide a better understanding of the benefits these projects provide for monarchs.