Effect of Carpobrotus edulis on the density of the lizard Chalcides striatus in a Galician coastal locality (Spain)
Chalcides striatus (Reptilia: Scincidae) is a common species of lizard in coastal zones of Galicia (Spain). Carpobrotus edulis (Aizoaceae, EPPO List of Invasive Alien Plants) is widely present in Galicia where it invades coastal areas. Transects have been established along the coast in the municipality of Arteixo (province of La Coruña) to determine the population densities of Chalcides striatus per hectare present in three different zones:
- Natural vegetation areas characterized by a Dauco gummifero-Festicetum pruinosae formation,
- Areas with 75-90% coverage by Carpobrotus edulis,
- Areas with more than 90% coverage by C. edulis.
Significant differences were observed in the densities of Chalcides striatus in the 3 different zones:
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Presence and abundance of C. edulis
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Average density in number of Chalcides striatus per hectare
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Without C. edulis
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188.1 ± 52.3
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C. edulis covering between 75 and 90%
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25.2 ± 9.8
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C. edulis covering more than 90%
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4.9 ± 4.9
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This survey suggested that the presence of C. edulis has a negative impact on Chalcides striatus, as the reptile had greatly reduced numbers when the invasive plant was present and was not found in some cases when the IAP has very high percentage cover.
Other studies conducted in Australia also concluded that reptiles preferred native vegetation formations because invasive plants created an environment with lower temperatures and it offered more limited opportunities to hide or catch prey. It is supposed that the same factors limit or reduce to zero Chalcides striatus populations in areas invaded by C. edulis in Galicia.
Sources
Galán P (2008) Efecto de la planta invasora Carpobrotus edulis sobre la densidad del eslizón tridáctilo (Chalcides striatus) en una localidad costera de Galicia. Boletín de la Asociación Herpetológica Española 19, 117-121. http://www.herpetologica.org/BAHE/038_Cons04-BAHE19.pdf