Variation in the population density of the Giant African Snail (Lissachatina fulica) in the Neotropical region

Abstract

The Giant African Snail (Lissachatina fulica) is one of the 100 world’s worst invasive species and has been recorded in the Neotropical region since the 1980s. Temperature and precipitation variables affect snail population density; however, these relationships have not been investigated for L. fulica on a regional scale. Here, we made the first description of variation in population density of L. fulica in the Neotropical region using a literature search, descriptive statistics, and a Principal Component Analysis (PCA). We found 22 studies covering 36 localities in six countries. The mean snail density was 11.55 ± 28.32 ind/m2, with the lowest value recorded in Cuba (0.0002 ind/m2) and the highest value recorded in Venezuela (150 ind/m2). These values were recorded between 21 % to 93 % of Human Footprint, 710 mm to 4438 mm of Annual Precipitation, 13 ºC to 27 ºC, Mean Temperature of the Coldest Quarter, and 3 ºC to 40 ºC of Temperature Seasonality. The PCA suggested that low densities can occur in various environmental conditions, whereas medium and high densities seem to appear in more specific climatic combinations. In conclusion, increased densities of Lissachatina fulica in the Neotropics seem to be influenced by climatic variations, especially the Mean Temperature of the Coldest Quarter and Annual Precipitation, supporting previous findings in the literature regarding the snail establishment. Future monitoring of this invasive species, performed at expanded spatial and temporal scales, may provide tools to establish a relationship between snail density values and impact.