The other side of the story: How evolution impacts the environment


Date:
June 5, 2023
Source:
University of Rhode Island
Summary:
Researchers show that an evolutionary change in the length of
lizards' legs can have a significant impact on vegetation growth
and spider populations on small islands in the Bahamas. This is
one of the first times, the researchers say, that such dramatic
evolution-to-environment effects have been documented in a natural
setting.


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FULL STORY ==========================================================================
The story of the peppered moths is a textbook evolutionary tale. As coal
smoke darkened tree bark near England's cities during the Industrial Revolution, white-bodied peppered moths became conspicuous targets for predators and their numbers quickly dwindled. Meanwhile, black-bodied
moths, which had been rare, thrived and became dominant in their newly
darkened environment.

The peppered moths became a classic example of how environmental change
drives species evolution. But in recent years, scientists have begun
thinking about the inverse process. Might there be a feedback loop in
which species evolution drives ecological change? Now, a new study by researchers at the University of Rhode Island shows some of the best
evidence yet for that very phenomenon.

In research published in the Proceedings of the National Academy of
Sciences, the researchers show that an evolutionary change in the
length of lizards' legs can have a significant impact on vegetation
growth and spider populations on small islands in the Bahamas. This
is one of the first times, the researchers say, that such dramatic evolution-to-environment effects have been documented in a natural
setting.

"The idea here is that, in addition to the environment shaping the traits
of organisms through evolution, those trait changes should feed back
and drive changes in predator-prey relationships and other ecological interactions between species," said Jason Kolbe, a professor of biological sciences at the University of Rhode Island and one of the study's senior authors. "And we really need to understand how those dynamics work so
we can make predictions about how populations are going to persist, and
what sort of ecological changes might result." For the last 20 years,
Kolbe and his colleagues have been observing the evolutionary dynamics of
anole lizard populations on a chain of tiny islands in the Bahamas. The
chain is made up of around 40 islands ranging from a few dozen to a
few hundred meters in area -- small enough that the researchers can
keep close tabs on the lizards living there. And the islands are far
enough apart that lizards can't easily hop from one island to another,
so distinct populations can be isolated from each other.

Previous research had shown that brown anoles adapt quickly to the characteristics of surrounding vegetation. In habitats where the diameter
of brush and tree limbs is smaller, natural selection favors lizards
with shorter legs, which enable individuals to move more quickly when
escaping predators or chasing a snack. In contrast, lankier lizards tend
to fare better where the tree and plant limbs are thicker. Researchers
have shown that this limb length trait can evolve quickly in brown anoles
-- in just a few generations.

For this new study, Kolbe and his team wanted to see how this evolved
limb- length trait might affect the ecosystems on the tiny Bahamian
islands. The idea was to separate short- and long-legged lizards on
islands of their own, then look for differences in how the lizard
populations affect the ecology of their island homes.

Armed with specialized lizard wrangling gear -- poles with tiny lassos
made of dental floss at the end -- the team captured hundreds of brown
anoles. They then measured the leg length of each lizard, keeping the
ones whose limbs were either especially long or especially short and
returning the rest to the wild.

Once they had distinct populations of short- and long-limbed lizards,
they set each population free on islands that previously had no lizards
living on them.

Since the experimental islands were mostly covered by smaller diameter vegetation, the researchers expected that the short-legged lizards
would be better adapted to that environment, that is, more maneuverable
and better able to catch prey in the trees and brush. The question the researchers wanted to answer was whether the ecological effects of those
highly effective hunters could be detected.

After eight months, the researchers checked back on the islands to look
for ecological differences between islands stocked with the short- and long-legged groups. The differences, it turned out, were substantial. On islands with shorter-legged lizards, populations of web spiders -- a key
prey item for brown anoles -- were reduced by 41% compared to islands
with lanky lizards. There were significant differences in plant growth as
well. Because the short-legged lizards were better at preying on insect herbivores, plants flourished. On islands with short-legged lizards,
buttonwood trees had twice as much shoot growth compared to trees on
islands with long-legged lizards, the researchers found.

The results, Kolbe says, help to bring the interaction between ecology
and evolution full circle.

"These findings help us to close that feedback loop," Kolbe said. "We
knew from previous research that ecological factors shape limb length,
and now we show the reciprocal relationship of that evolutionary change
on the environment." Understanding the full scope of interactions between evolution and ecology will be helpful in predicting environments outcomes,
the researchers say - - particularly as human activities accelerate the
pace of both evolutionary and ecological change worldwide.

The research was funded by the National Science Foundation (DMS-1716803
and DEB-2012985).

* RELATED_TOPICS
o Plants_&_Animals
# Nature # Frogs_and_Reptiles # Evolutionary_Biology
o Earth_&_Climate
# Ecology # Environmental_Issues # Environmental_Awareness
o Fossils_&_Ruins
# Evolution # Charles_Darwin # Early_Humans
* RELATED_TERMS
o Lizard o Evolution o Yellow_sac_spider o Hydroponics o
Green_Iguana o Brown_recluse_spider o Wild_Cat o Ecotourism

========================================================================== Story Source: Materials provided by University_of_Rhode_Island. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Jason J. Kolbe, Sean T. Giery, Oriol Lapiedra, Kelsey P. Lyberger,
Jessica N. Pita-Aquino, Haley A. Moniz, Manuel Leal, David
A. Spiller, Jonathan B. Losos, Thomas W. Schoener, Jonah
Piovia-Scott. Experimentally simulating the evolution-to-ecology
connection: Divergent predator morphologies alter natural food
webs. Proceedings of the National Academy of Sciences, 2023; 120
(24) DOI: 10.1073/pnas.2221691120 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/06/230605181213.htm

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