Shifting rainfall patterns will affect whether an imperiled butterfly
survives climate change

Date:
February 7, 2022
Source:
North Carolina State University
Summary:
When we think of climate change, we often imagine how a warmer world
will impact species, but a new study highlights the importance
of changes in precipitation. The finding suggests that paying
attention to the environmental triggers within each species'
lifecycle will help us better understand how they will be affected
by climate change.



FULL STORY ==========================================================================
When we think of climate change, we often imagine how a warmer world
will impact species, but a new study highlights the importance of
changes in precipitation. The finding suggests that paying attention to
the environmental triggers within each species' lifecycle will help us
better understand how they will be affected by climate change.


==========================================================================
The research focused on the Miami blue butterfly (Cyclargus thomasi bethunebakeri), a federally-listed endangered species that exists solely
in a pocket of habitat in southern Florida. Their federal status directs
more resources towards their conservation, and understanding the Miami
blue's lifecycle in relation to our changing climate is critical for
predicting how they will fare in the future.

Like many tropical insect species, the lifecycle of Miami blue butterflies includes a state called "diapause," when larvae suspend their development during dry conditions. The onset of the wet season triggers diapausing
larvae to restart their development into adult butterflies. The duration
of the dry period, and therefore the duration of diapause, can have a significant effect on population numbers. If larvae have a short diapause,
then they are more likely to reach adulthood and reproduce than if there
is a long dry season with an extended period of diapause.

"We found that shifting rainfall patterns can determine whether the
Miami blue butterfly populations grow or shrink, even without any
other environmental variables changing," says Erica Henry, a postdoc
in applied ecology at NC State and author of the study. "This is
not only concerning for this rare butterfly, but for all insects in precipitation-driven systems. Both the tropics and rainfall patterns
have been largely overlooked in the conversation about climate change
and animal lifecycles." Several species have precipitation-based
environmental triggers within their lifecycles. And unlike temperature,
which largely trends up under climate change, shifts in precipitation
will be more varied and nuanced across the globe: some areas will dry
out, some will become inundated, and some will see no change. And in some places, like southern Florida, it's uncertain how rainfall patterns will
shift with climate change. To account for this, the researchers simulated future conditions using 20 different climate models to test how Miami blue populations would respond. In most of those tests, butterfly populations declined when rainfall was delayed and the diapause duration increased,
even when all other environmental conditions did not change.

"The tropics, and more specifically that fuzzy area we call the
sub-tropics, covers an extremely diverse set of ecosystems that are much
more sensitive to projected shifts in precipitation than temperature,"
says Adam Terando, a U.S.

Geological Survey Research Ecologist and adjunct professor in
the Department of Applied Ecology at NC State who co-authored the
study. "The problem is, there's also a lot more uncertainty about those precipitation changes as the planet warms. We wanted to bring attention
to these rainy-season ecosystems and demonstrate how linking climate
science with ecology can give us new insights into what to expect in
the future." This research is one of the first efforts to examine a
tropical insect under climate change using the lens of precipitation
rather than temperature.

Tropical insect species in areas that are expected to dry under climate
change will likely see similar impacts on their lifecycles, possible
declines. In fact, changes in precipitation patterns may explain currently declining populations.

"Climate change is happening everywhere," says Henry. "We can get a better handle on what actions may minimize the negative impacts to biodiversity
by thinking more broadly about what that change really means in different
parts of the globe." The article, "Shifting precipitation regimes alter
the phenology and population dynamics of low latitude ectotherms," was published in the journal Climate Change Ecologyon 3 February 2022. The
paper is also authored by William Morris from Duke University, Jaret
Daniels from the University of Florida, and Nick Haddad from Michigan
State University. The research was funded by a Southeast Climate
Adaptation Science Center Global Change Fellowship for Erica Henry and
the Disney Conservation Fund and Florida Keys National Wildlife Refuges.

========================================================================== Story Source: Materials provided by
North_Carolina_State_University. Original written by Michelle
Jewell. Note: Content may be edited for style and length.


========================================================================== Related Multimedia:
* Miami_blue_butterfly ========================================================================== Journal Reference:
1. Erica H. Henry, Adam J. Terando, William F. Morris, Jaret
C. Daniels,
Nick M. Haddad. Shifting precipitation regimes alter the phenology
and population dynamics of low latitude ectotherms. Climate Change
Ecology, 2022; 3: 100051 DOI: 10.1016/j.ecochg.2022.100051 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220207100125.htm

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