And The Carnage Will Continue …

The newspaper article to announce the actions to eradicate brown anoles (Anolis sagrei) in Santzepu, Sheishan District, Chiayi County, Taiwan.

On the 28th of April, 2011, I posted an article here in AA about the actions of the Taiwanese authorities to try and remove Anolis sagrei in Chiayi County. On the 25th of June, 2011, it was announced that they have acquired more funding (they ran out of funds previously) and that they will continue with these actions this year.

The alarming part is how they (whoever wrote the article) mislead the public, who believes in what is said in the newspapers, by providing incorrect information in the article.

They report that in the past two years 127,458 brown anoles were removed, and since the past winter was colder than usual, they believe they can eradicate this species by again paying the public a bounty of N.T.$ 20 (ca. U.S.$ 0.70) for every lizard they collect. I am confident they will run out of funds again, and the brown anole will persist! I am also convinced that something other than conservation is driving these actions.

According to the article, Anolis sagrei breeds only for 4 months. Ha! In a study we conducted on reproduction in A. sagrei in Taiwan (paper is submitted, and is being reviewed) we found that these lizards have a very long reproductive cycle in Taiwan, and that some individuals are reproductive throughout the year. What they did get right was when they stated that these lizards can build up large populations within a short period of time, which incidentally, is why I believe they will fail. The few lizards they remove will soon be replaced.

In the article they also claim that Anolis sagrei has no natural enemies in Taiwan. This is ridiculous, because we have published articles about the long-tailed skink (Eutropis longicaudata, formerly Mabuya longicaudata; Norval et al., 2004. Herpetological Review. 35(4): 393–394), the mountain wolf snake (Lycodon ruhstrati ruhstrati ; Norval et al., 2007 and Norval & Mao, 2008), the Malay night heron (Gorsakius melanolophus; Norval et al., 2011), and the brown shrike (Lanius cristatus; Chiu et al., 2011) preying on brown anoles in Taiwan. I also believe there are other predators that prey on Anolis sagrei in Taiwan, they just simply have not been observed yet.

According to the authors of the article, A. sagrei is harmful to the environment and preys on local lizards. From nearly a thousand A. sagrei that we examined, we found only five instances where they preyed on small lizards, of which three were conspecifics. And all the instances of predation on smaller lizards that we documented took place in areas where there was great anthropogenic disturbances (Norval, 2007). As can be expected, from our diet studies we found that ants make up the largest part of the diet of A. sagrei in Taiwan (Huang et al., 2008b and Norval et al., 2010), but this was not mentioned in the newspaper article. In fact, we found that even though predation on ants does not affect the overall numbers of ants, the predation on Pheidole fervens is so severe that it can actually alter the ant community structure (Huang et al., 2008a). It was hypothesized that the effect was possibly due to direct predation on the dominant ant species, and a possible foraging shift of these ants as a result of it, which allowed less competitive species to increase. In another study, which was an in depth examination of the ants from an earlier diet study on A. sagrei in Taiwan, we found that the big head ant (Pheidole megacephala) was the dominant prey item (Norval et al., 2011). Pheidole megacephala is an invasive pest ant, introduced into the tropics and subtropics worldwide through anthropogenic activities, and can pose a serious threat to local invertebrate communities, because it will severely reduce or eliminate native insects, especially other ants. If predation by A. sagrei on Pheidole megacephala has similar effects, the presence of this exotic lizard species in areas disturbed by anthropogenic activities in Taiwan could actually have beneficial influences on local ant species. Of course, none of this is mentioned to the public.

Big head ants (Pheidole megacephala) from the stomach of a male Anolis sagrei (SVL = 46 mm), collected in in Santzepu, Sheishan District, Chiayi County, Taiwan.

This entry was posted in Anoles and Anolologists in the News, Introduced Anoles. Bookmark the permalink.

2 Responses to And The Carnage Will Continue …

  1. Rich Glor says:

    Do you still think that native lizards are getting caught up in the anole eradication efforts? The misidentified newspaper photos in your last post were pretty troubling.

  2. Gerrut Norval says:

    I am convinced that native lizards are still being killed as a result of the brown anole eradication campaign. Firstly, I am not aware of any articles to correct that misidentification that appeared in that newspaper article. Secondly, the average citizen does not value lizards and simply don’t care which get removed. Thirdly, a sub-adult Japalura swinhonis or a Takydromus formosanus that had suffered some tail loss can easily be mistaken for a brown anole by the general public. A case in point, a few years ago we trained some biology university students to help us collect some brown anoles for a project we were doing. Even they sometimes collected the wrong lizards!

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