Abstract <p>Climate warming and landscape level changes are considered to be among the most serious of anthropogenic stresses to the environment. Consequences of land-use change include habitat loss and fragmentation, which are considered to be primary forces in the decline of species worldwide. Climate change not only has direct effects on biodiversity, but it also exacerbates the harmful effects of other human-mediated threats. Understanding species’ response to landscape structure and climate change can inform our understanding of their ecology and aid in the development of management and conservation strategies. Monarch butterflies (<i>Danaus plexippus</i>) are well-known long-distance migrants whose population has suffered a drastic decline in recent decades. Here I investigated response of monarchs’ breeding phenology to climate warming and also assessed landscape characteristics associated with monarchs’ breeding-site and habitat selection during different seasons. My result demonstrated that the breeding phenology of monarchs was more responsive to temperature in warmer regions than in colder ones. I also found that, although often neglected, landscape compositional and configurational heterogeneity can be of great importance for monarch conservation. I recommend that the landscapes surrounding monarch’s ideal habitat, like grasslands, be managed to maintain a diversity of land cover types. Implications for insect conservation: My finding demonstrates temporal shifts in the breeding phenology of monarchs in response to global warming, which can lead to a mismatch between a butterfly and its host plants and can further alter the species interactions. My results also showed the importance of landscape compositional and configurational heterogeneity along with grassland patches for the monarch population. Therefore, wildlife managers should focus on maintaining diverse land-cover types with different landscape structures for better management of monarch populations.</p> Implications for conservation <p>In today’s world, land use, land cover change, and climate change have led to a decline in biodiversity. Climate change is causing significant shifts in insect phenology, which can affect insect abundance, species interactions, and ecosystem services. My finding provides evidence of temporal shifts in the breeding phenology of monarchs in response to global warming, which can lead to a mismatch between a butterfly and its host plants and can further alter the species interactions. Even though we cannot control the climate, this knowledge may help to better prepare for monarch conservation. My results showed the importance of landscape compositional and configurational heterogeneity along with grassland patches for the monarch population. As conservation resources become increasingly limited, targeted management at the landscape level is necessary to get the most results for the conservation dollar. Based on my findings, instead of only focusing on maintaining grassland areas, managers should equally focus on maintaining diverse land-cover types with different landscape structures.</p>