Tracking climate impacts on the migratory monarch butterfly

Global Change Biology
By: , and 

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Abstract

Understanding the impacts of climate on migratory species is complicated by the fact that these species travel through several climates that may be changing in diverse ways throughout their complete migratory cycle. Most studies are not designed to tease out the direct and indirect effects of climate at various stages along the migration route. We assess the impacts of spring and summer climate conditions on breeding monarch butterflies, a species that completes its annual migration cycle over several generations. No single, broad-scale climate metric can explain summer breeding phenology or the substantial year-to-year fluctuations observed in population abundances. As such, we built a Poisson regression model to help explain annual arrival times and abundances in the Midwestern United States. We incorporated the climate conditions experienced both during a spring migration/breeding phase in Texas as well as during subsequent arrival and breeding during the main recruitment period in Ohio. Using data from a state-wide butterfly monitoring network in Ohio, our results suggest that climate acts in conflicting ways during the spring and summer seasons. High spring precipitation in Texas is associated with the largest annual population growth in Ohio and the earliest arrival to the summer breeding ground, as are intermediate spring temperatures in Texas. On the other hand, the timing of monarch arrivals to the summer breeding grounds is not affected by climate conditions within Ohio. Once in Ohio for summer breeding, precipitation has minimal impacts on overall abundances, whereas warmer summer temperatures are generally associated with the highest expected abundances, yet this effect is mitigated by the average seasonal temperature of each location in that the warmest sites receive no benefit of above average summer temperatures. Our results highlight the complex relationship between climate and performance for a migrating species and suggest that attempts to understand how monarchs will be affected by future climate conditions will be challenging.
Publication type Article
Publication Subtype Journal Article
Title Tracking climate impacts on the migratory monarch butterfly
Series title Global Change Biology
DOI 10.1111/j.1365-2486.2012.02751.x
Volume 18
Issue 10
Year Published 2012
Language English
Publisher Wiley
Publisher location Hoboken, NJ
Contributing office(s) Patuxent Wildlife Research Center
Description 11 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Global Change Biology
First page 3039
Last page 3049
Country United States
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