Monarchs face many threats and stressors that result in declining populations in both the eastern and western regions of their North American range. The most significant impacts come from the loss of habitat for breeding, migrating, and overwintering. In addition, indiscriminate use of chemicals to control insects and weeds can have harmful unintended consequences for monarchs; a changing climate is making some habitat less suitable and forcing changes in migratory patterns; and monarchs face many risks from natural enemies such as predators, parasitoids, and diseases.
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Breeding Habitat LossThe loss of breeding habitat through much of the United States has strongly influenced the decline in overwintering monarch population.
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Overwintering Habitat LossConservation and management actions are needed to ensure the future of overwintering habitats for monarchs in California and Mexico.
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Climate ChangeClimate change models suggest that changes in the monarch migration and breeding range may force monarchs to change their migratory patterns.
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PesticidesBeneficial insects like monarchs and other pollinators can be negatively affected by using pesticides to control unwanted insect and plant species.
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Natural EnemiesAlthough toxins from milkweed may, in some ways, protect them, monarchs of all life stages are vulnerable to predation and disease.
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Other Anthropogenic ConcernsWise management practices are essential in providing long-term habitat for monarchs and other wildlife. However, if appropriate guidelines are not followed, monarchs and other organisms using the site could be harmed.
