Biodiversity may limit invasions: Lessons from lizards on Panama Canal islands

August 09, 2020

When the U.S. flooded Panama's Chagres River valley in 1910, Gatun Lake held the record as the world's biggest reservoir. This record was surpassed, but researchers at the Smithsonian Tropical Research Institute (STRI), who are now studying invading lizards on the tiny islands that dot the lake, discovered that islands with native lizards act as another kind of reservoir, harboring the parasites that control invaders. The study, published in the journal Biology Letters, is valuable experimental evidence that biodiversity is better, making ecosystems more resistant to invasion.

As part of another study to find out how many generations it takes for slender anole lizards (Anolis apletophallus) to adapt to climate change, a research team led by Christian Cox, a visiting scientist at STRI from Georgia Southern University, and Mike Logan from the University of Nevada, Reno, transplanted lizards from the tropical forest on the mainland to the islands, which tend to be hotter and drier. Before the transplant, they did a general health check of the lizards that included counting the number of parasites (mites) on their bodies.

When they came back several times during the next two years to see how the lizards were doing in their new habitats, they recounted the number of mites.

"We found that on the islands with no resident species of anole lizard, the slender anole lizards that were transplanted to the islands lost their mites within a single generation, and the mites are still gone several generations later (up until the present)," Cox said. "Indeed, individual founding lizards that had mites during the initial transplant had no mites when they were later recaptured. In contrast, anole lizards that were transplanted to an island with another resident (native) species of anole lizard kept their mites for three generations, and some of the founders on the two-species island never lost their mites."

"Our study turned out to be a large-scale experimental test of the enemy release hypothesis," said Logan, who did this work as a three-year STRI/Tupper postdoctoral fellow. "Often, when an invasive animal shows up in a new place, all of its pathogens and parasites are left behind or do not survive, giving it an extra survival advantage in the new place: thus the term enemy release."

The team also found that the two-species island had lower density and lower biomass per unit area of the invasive lizard species, indicating that the continued presence of the mites may be keeping their populations under control.

"Our study is a clear example of something that conservationists have been trying to communicate to the public for some time," Logan said. "Diverse native communities sometimes function as 'enemy reservoirs' for parasites and diseases the keep down the numbers of invaders."
-end-
Funding for this study was provided by the Smithsonian Institution, Georgia Southern University, the Theodore Roosevelt Memorial Foundation and the American Museum of Natural History.

The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a unit of the Smithsonian Institution. The institute furthers the understanding of tropical biodiversity and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems.

Smithsonian Tropical Research Institute

Related Climate Change Articles from Brightsurf:

Are climate scientists being too cautious when linking extreme weather to climate change?
Climate science has focused on avoiding false alarms when linking extreme events to climate change.

Mysterious climate change
New research findings underline the crucial role that sea ice throughout the Southern Ocean played for atmospheric CO2 in times of rapid climate change in the past.

Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.

Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.

Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.

Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.

A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.

Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).

Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.

Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.

Read More: Climate Change News and Climate Change Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.