Will the endangered butterfly survive climate change? It depends on the change in precipitation

Photo of a blue Miami butterfly (Cyclargus thomasi bethunebakeri). Recent studies show that changes in rainfall due to climate change will have a greater impact on the Miami blue population than temperature changes. Credit: Jarrett Daniels

When we think about climate change, we often imagine how a warmer world will affect species, but new research highlights the importance of change in precipitation. The result suggests that paying attention to environmental factors in the life cycle of each species will help us better understand how they will be affected by climate change.

The study focused on the Miami Blue Butterfly (Cyclargus thomasi bethunebakeri), which is endangered in the federal list, which exists exclusively in the pocket of living in South Florida. Their federal status directs more resources to their conservation, and understanding the life cycle of Miami blue due to our changing climate is crucial to predicting how they will fare in the future.

Like many species of tropical insects, the life cycle of Miami blue butterflies includes a condition called “diapause” when larvae suspend their development in dry conditions. The onset of the wet season causes diapause of larvae to resume their development in adult butterflies. The length of the dry season and thus the duration of diapause can have a significant impact on population size. If the larvae have a short diapause, they are more likely to reach adulthood and reproduce than during a long dry season with a long diapause period.

“We found that changing rainfall can determine whether Miami’s blue butterfly population is growing or shrinking, even without any other environmental variables,” says Erica Henry, postdoc for applied ecology at NC and author of the study. “This applies not only to this rare butterfly, but to all insects in systems that act on precipitation. Both the tropics and rainfall were largely ignored when it came to climate change and the life cycle of animals. ”

A change in the precipitation pattern will affect whether the butterfly survives due to climate change

A recent study from the University of North Carolina found that changing rainfall will determine whether Miami’s blue butterfly population is growing or shrinking, even without changing other environmental variables. Author: Neil McCoy

Several species have environmental triggers based on precipitation in their life cycle. And unlike temperatures, which are mostly rising as a result of climate change, changes in rainfall will be more varied and nuanced around the globe: some areas will dry up, some will become flooded, and some will not notice the changes. And in some places, such as South Florida, it remains uncertain how precipitation patterns will change with climate change. To account for this, researchers simulated future conditions using 20 different climate models to test how the Miami blue population would react. In most of these tests, butterfly populations declined when precipitation was delayed and diapause duration increased, even if all other environmental conditions did not change.

“The tropics, or more specifically the obscure area we call the subtropics, cover an extremely diverse set of ecosystems that are sensitive to precipitation shifts,” said Adam Teranda, a U.S. Geological Survey ecologist and associate professor of applied ecology at the state. NC, who co-authored the study. “The problem is that compared to temperature, there is much more uncertainty about how precipitation will change as the planet warms. We wanted to draw attention to these ecosystems during the rainy season and demonstrate how the link between climate science and ecology can give us a new insight into what to expect in the future. ”

This study is one of the first efforts to study tropical insects under climate change using precipitation lenses rather than temperature. Tropical insect species in areas that are expected to dry up as a result of climate change are likely to have similar impacts on their life cycle, possibly declining. In fact, changes in precipitation patterns may explain the declining population now.

“Climate change is happening everywhere,” says Henry. “We can better understand what actions can minimize the negative impact on biodiversity by thinking more broadly about what these changes actually mean in different parts of the globe.”

Reference: “Changing precipitation regimes changes the phenology and population dynamics of ectotherms in low latitudes” Eric H. Henry, Adam J. Teranda, William F. Morris, Jarrett S. Daniels and Nick M. Haddad, January 19, 2022, Ecology of climate change.
DOI: 10.1016 / j.ecochg.2022.100051

The article “Change in precipitation regimes changes the phenology and dynamics of the population of low-latitude ectotherms” was published in the journal Ecology of climate change February 3, 2022 The author of the article is also William Morris of Duke University, Jarrett Daniels of University of Floridaand Nick Haddad of the University of Michigan. The study was funded by the Eric Henry Scholarship and the Scholarship Center for Climate Adaptation Science on Southeast Climate Adaptation for Erica Henry and the Disney Conservation Foundation and the Florida Keys National Wildlife Refuge. Will the endangered butterfly survive climate change? It depends on the change in precipitation

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