Eradicating black rats on Palmyra Atoll uncovers eye-opening indirect effects

Junglekeeper · Nov 12, 2020

Eradicating black rats on Palmyra Atoll uncovers eye-opening indirect effects

Eradication of the rats—which was conducted in 2011—did in fact result in a resurgence of vegetation on Palmyra. And not only that. The Asian tiger mosquito was wiped out, while two species of land crab emerged, adding to the atoll's biodiversity.
Click to expand...

Also, from a related article (listed at the end of the article above):

Without rats to feed on, the mosquitoes were left with only humans to bite. But rather than being bitten more, people eventually were not bitten at all. Researchers began to wonder if the Asian tiger mosquito had disappeared along with the rats. Now, in the journal Biology Letters, a team of UC Santa Barbara scientists and colleagues at the United States Geological Survey (USGS) chronicles this unique example of co-extinction.

Source: Disappearing act: Biologists document the secondary extinction of a disease-carrying mosquito
Click to expand...

Acerholic · Nov 12, 2020

And without rats and vermin what do the birds of prey feed on. Eradication of one species always has a knock on effect !!!! What did they sing in the Lion King film, ' The circle of life'

wcutler · Nov 12, 2020

That first quote "did in fact result in a resurgence of vegetation on Palmyra" is a little misleading. It goes on to say

In the absence of rats, according to a population model the researchers built based on a decades' worth of data on coconut seed production, growth and survival, the coconut palms' population growth rate increased by 10%—enough to eventually overtake the island, had the managers not stepped in with an aggressive coconut palm removal project.
Click to expand...

and

"Coconuts have a very different 'nutritional' profile from the native tree species on this island, with much more carbon and less nitrogen," Miller-ter Kuile said. "When these trees die, because they have different nutrient profiles from native plants, they are likely to break down differently—and more slowly—and influence rates of decomposition." In addition, she said, native seabirds do not nest in coconut palms, which would deprive the atoll of the nutrients in their guano, which, in turn, "would lead to what would likely be a fairly nutrient-poor system, which discourages other native plants from growing in those areas."
Click to expand...

In this case, the headline was less misleading than the quote.

Michael F · Nov 12, 2020

Acerholic said: ↑

And without rats and vermin what do the birds of prey feed on. Eradication of one species always has a knock on effect !!!! What did they sing in the Lion King film, ' The circle of life'
Click to expand...

I'd assume there weren't any birds of prey; they rarely occur on small islands far offshore (the Galapagos Hawk is a rare exception, but the Galapagos are a lot larger than Palmyra). The absence of raptors is just one reason why the introduced rats were so devastating - no natural predators to keep them under control.

Junglekeeper · Nov 12, 2020

According to Invasive rat eradication strongly impacts plant recruitment on a tropical atoll:

Overall, seedling recruitment increased for five of the six native trees species examined. While pre-eradication monitoring found no seedlings of Pisonia grandis...post-eradication monitoring documented a notable recruitment event immediately following eradication...Two other locally rare native trees with no observed recruitment in pre-eradication surveys had recruitment post-rat eradication. However,we also found, by five years post-eradication, a 13-fold increase in recruitment of the naturalized and range-expanding coconut palm Cocos nucifera...Rat eradication released non-native C. nucifera, likely with long-term implications for community composition, potentially necessitating future management interventions. Eradication, nevertheless, greatly benefitted recruitment of native tree species. If this pattern persists over time, we expect long-term benefits for flora and fauna dependent on these native species.
Click to expand...

Log in or Sign up

Eradicating black rats on Palmyra Atoll uncovers eye-opening indirect effects

Junglekeeper Esteemed Contributor 10 Years

Acerholic Paragon of Plants Forums Moderator VCBF Cherry Scout Maple Society

wcutler Paragon of Plants Forums Moderator VCBF Cherry Scout 10 Years

Michael F Paragon of Plants Forums Moderator 10 Years

Junglekeeper Esteemed Contributor 10 Years

Share This Page