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Anolis carolinensis (green anole) Management Information 1.0 Introduction Anolis carolinensis or the green anole is a moderate sized arboreal lizard native to the southeastern United States (Muensch et al., 2006). Most likely spread through unintentional transport, alien populations have managed to establish on numerous islands in the Caribbean Sea and Pacific Ocean (Eaton et al., 2001; Powell, 2002; Muensch et al., 2006). While many of these populations are not widely dispersed, very little is known about their impact on native biodiversity or local economies. On Chichijima and Hahajima, in the Ogasawara Islands of Japan A. carolinensis has become widespread and abundant, reaching average densities of 1,270 individuals per ha (Okochi et al., 2006). The increased predation pressure on native endemic insect populations has played a significant role in the extinctions of species such as the tricolored tiger longhorn (Xylotrechus takakuwai), the Ogasawara tumbling flower beetle (Glipa ogasawarensis) and the Ogasawara carabid beetle (Colpodes boninensis) as well as contributed to the decline of other insects like the endemic cicada Meimuna boninensis (Toda et al., 2010), insect pollinators like the endemic butterfly Celastrina ogasawarensis (Abe et al., 2008; Toda et al., 2010), endemic odonates (Yoshimure & Okochi, 2005) and diurnal longicorn beetles (Makihara et al., 2004). Furthermore, A. carolinensis is noted as a predator on the only native terrestrial reptile on Chichijima and Hahajima, the Ogasawara snake-eyed skink, Cryptoblepharus nigropunctatus (Toda et al., 2010).

2.0 Preventative Measures Once established, Anolis carolinensis is extremely difficult to control due to its high tolerance of starvation, high evasiveness, being well camouflaged and the ability to disperse rapidly (Toda et al., 2010). On the Ogasawara Islands in Japan, massive declines in endemic insect populations have been associated with the invasion of A. carolinensis on two of the islands, Chichijima and Hahajima. As the insect populations on the surrounding islands appear to be healthy (Yoshimura & Okochi, 2005) and given the difficulty of A.

IUCN SSC Invasive Species Specialist Group carolinensis control, priority should be given to stopping the spread of A. carolinensis to these surrounding islands (Toda et al., 2010).

To do this, it is particularly important to control vectors such as the transportation of building supplies, materials and tourists around the islands (Toda et al., 2010). To reduce the chances of A. carolinensis getting on board these ships, intensive trapping was undertaken round the piers, with about 1000 traps placed (see Physical Control) and with 34 volunteers trapping in the nearby residential area (Toda et al., 2010). While a reduction of density was achieved (by 35% in these areas) immigration of individuals from the mountainsides in autumn rapidly increased numbers and highlighted the need for barrier fences. These however are difficult to set along roads or in urban areas (Toda et al., 2010). After 3 years of trapping, transit points used frequently by A. carolinensis have been identified as future target sites for intense trap deployment, preferably with barrier fences to block reinvasion (Toda et al., 2010).

Exclusion fences must be designed keeping in mind the ability of A. carolinensis to rapidly climb smooth barriers (Toda et al., 2010). Pacara et al. (1983; in Toda et al., 2010) introduced fences against anoles that had an added 20 cm wide polypropylene roof. Furthermore, vegetation was pruned for 2 m outside the fence to prevent lizards jumping over the fence. The introductions of three Anolis spp. (not A. carolinensis) inside the fence found that they were unable to escape over a period of weeks (Pacara et al., 1983; in Toda et al., 2010). While these fences were shown to be effective in blocking movement of anole lizards at the Caribbean study site, the landscape of the Ogasawara Islands is complicated and prone to typhoons, making the idea of roofed fences impractical (Toda et al., 2010). Indoor and field trials have determined that a stainless steel mesh fence 0.8 – 1 m high and angled outwards at 15° with a 30 cm wide Teflon sheet covering the top of the fence is effective at blocking movement of anole lizards (Toda et al., 2010). However, it is still necessary to have a 2 m wide vegetation free buffer zone on either side of the fence to prevent individuals jumping over, which could be problematic if a fence needed to be

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placed in an area of native tree vegetation (Toda et al., 2010). Fences deployed at Shin- Yuhigaoka and on the tip of Minamizaki on Hahajima along with concurrent intensive trapping programs have shown signs that these fences can help regenerate endemic insect populations with monitoring still ongoing (Toda et al., 2010).

3.0 Monitoring In the United States, use of burlap bands on tree trunks were shown to be an effective non- destructive monitoring tool for sampling A. carolinensis populations as well as other arboreal reptile species (Horn & Hanula, 2006). In contrast to other monitoring methods used for lizards such as pitfall traps, glueboards and refuge tubes, burlap bands are not known to cause undue mortality or stress to the individual (Horn & Hanula, 2006). They consist of a 1 x 1 m piece of burlap fabric, folded in half and then sewn together about 3 cm from the folded edge. A 1.5 m length of cotton rope was then threaded through the fold and used to tie the fabric around the trunk of the tree (Horn & Hanula, 2006). To check the burlap band, the rope is untied and the fabric removed carefully while walking slowly around the tree to observe any individuals that may be present underneath (Horn & Hanula, 2006).

While this technique may not be particularly useful in areas where A. carolinensis is widespread and present in high densities such as Chichijima and Hahajima, it is simple and does not alter the natural habitat (Horn & Hanula, 2006) and thus could be used as an early detection tool on the uninvaded Ogasawara Islands or other such areas with a higher chance of A. carolinensis introduction.

4.0 Physical Control Reptile control techniques are poorly developed compared to mammal bird or insect control techniques, as they do not cause serious damage to agriculture or forestry systems (Toda et al., 2010). According to Toda et al. (2010), the development of effective reptile- capture techniques needs to involve no special technology, allowing any regular work staff

IUCN SSC Invasive Species Specialist Group to operate any devices; long-term continuous pressure needs to maintained on the target population, which requires the possibility of capture during periods of inactivity; and the effects on native species, the natural environment and human health must be minimised.

Before the development of traps, hand catching and angling were the primary management tools used (Karube, 2010; Toda et al., 2010). While angling was reported to be effective with a skilled worker capable of catching 20 – 30 A. carolinensis individuals in an hour, it is restricted by season, time of day, and weather; the best results coming from high-density habitats on sunny mornings from April to June (Toda et al., 2010). Toda et al. (2010) also state that this method is further restricted by only being able to be used while individuals are feeding.

At present, following reports that anole lizards were often caught in adhesive traps used for insect surveys (Tsuyoshi Ono, pers. comm.; in Toda et al., 2010), adhesive cockroach traps have been deployed successfully on the trunks of trees to capture A. carolinensis individuals (Toda et al., 2010). These traps have since been upgraded for repeated use, weather resistance and easy disposal while also reducing their production costs (Toda et al., 2010). While noted to be less efficient than intensive angling, the use of adhesive traps is thought to give superior control, with each trap exerting long-term continuous pressure on A. carolinensis populations. (Toda et al., 2010). Furthermore, as individuals frequently move between the tree crown and the ground via the trunk, use of attractant or food baits are not necessary; the trap is simply deployed on the tree trunk (Toda et al., 2010). Toda et al. (2010) state that polypropylene traps are currently being developed in response to studies carried out on Chichijima and Hahajima, however further details are not given.

5.0 Chemical Control Consumer repellent sprays available for use against habu vipers were investigated for possible use against A. carolinensis however these were not implemented as the risks of negative environmental impacts were too high (Toda et al., 2010).

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6.0 Integrated Management While trapping and other physical control techniques can achieve lower densities of A. carolinensis on a local scale, the total populations on the invaded islands of Chichijima and Hahajima are estimated to number in the millions (Toda et al., 2010). As simultaneous and island wide eradication is therefore not likely to be feasible, exclusion of A. carolinensis from specific areas of intensive trapping using fences (see Preventative Measures) is necessary to fragment their dispersal range and allow the restoration of endemic species in key locations (Toda et al., 2010).

7.0 References Abe, T., Makino, S., & Okochi, I. (2008). Why have endemic pollinators declined on the Ogasawara Islands? Biodiversity Conservation, 17, 1465–1473. Eaton, J.M., Howard, K.G., & Powell, R. (2001). Anolis carolinensis. Geographic distribution. Herpetological Review, 32, 118. Horn, S., & Hanula, J.L. (2006). Burlap bands as a sampling technique for green anoles (Anolis carolinensis) and other reptiles commonly found on tree boles. Herpetological Review, 37(4), 427-428. Karube, H. (2010). Endemic insects in the Ogasawara Islands: Negative impacts of alien species and a potential mitigation strategy. In K. Kawakami and I. Okochi (eds.), Restoring the Oceanic Island Ecosystem, 2010; 133. Translated from the Japanese original, Karube, H. (2009). Global Environmental Research, 14, 33–38. With permission of the Association of International Research Initiatives for Environmental Studies. Makihara, H., Kitajima, H., Goto, H., Kato, T., & Makino, S. (2004). An evaluation of predation impact of the introduced lizard Anolis carolinensis on the endemic insect fauna of the Ogasawara Islands based on insect collection records and feeding experiments,

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with special reference to longicorn beetles (Insecta: Coleoptera: Cerambycidae) Bulletin of the Forestry & Forest Products Research Institute, 3(2), 165-183. Muensch, A.J., Leininger, P.D., Werth, D.E., Fawks, A.M., & Thomas, S.M. (2006). The Anoles of Coconut Island, Kaneohe Bay, Oahu, Hawaii. Iguana, 13(3), 199. Okochi, I., Yoshimura, M., Abe, T., & Suzuki, H. (2006). High population densities of an exotic lizard, Anolis carolinensis and its possible role as a pollinator in the Ogasawara Islands. Bulletin of the Forestry & Forest Products Research Institute, 5(4), DEC 2006. 265-269. Powell, R. (2002). Anolis carolinensis (Green anole). Herpetological Review, 33(4), 321. Toda, M., Takahashi, H., Nakagawa, N., & Sukigara, N. (2010). Ecology and control of the green anole (Anolis carolinensis), an invasive alien species on the Ogasawara Islands. In Restoring the Oceanic Island Ecosystem. Yoshimura, M., & Okochi, I. (2005). A decrease in endemic odonates in the Ogasawara Islands, Japan. Bulletin of the Forestry & Forest Products Research Institute, 4(1), 45- 51.