Diversity and distribution of family Araceae in Doi Inthanon National Park, Chiang Mai province

Abstract

Species of the family Araceae are known for their ethnobotanical utilization; however their species diversity is less documented. This study aimed to clarify the relationships between species diversity of the Araceae and altitudinal gradients in the mountain ecosystems in Doi Inthanon National Park, Chiang Mai province, northern Thailand. In 2014, tree permanent plots (4 m x 4 m) including one strip plot (5 m x 500 m) were established every 300 m above mean sea level (amsl) in the range 300-2565 m amsl. All species of Araceae were investigated and environmental factors were also recorded. The results showed that 23 species were mostly found in the rainy season and identified into 11 genera: Alocasia, Amorphophallus, Arisaema, Colocasia, Lasia, Pothos, Rhaphidophora, Remusatia, Sauromatum, Scindapsus, and Typhonium. The top five dominant species were Arisaema consanguineum, Amorphophallus fuscus, Remusatia hookeriana, Amorphophallus yunnanensis and Colocasia esculenta. Low species diversity was found at the lowest and highest altitude. A generalized linear model was used to detect specific environmental factors; only five species were determined using soil pH, a percentage of sand, the quantity of organic matter, a percentage of clay, light intensity, elevation and a percentage of silt, respectively. The results indicated that high species diversity of the Araceae was supported by the wide range of ecological niches. However, anthropogenic factors formed the main threats to decreased biodiversity. Thus, to maintain high biodiversity, not only the niches but also the threats should be of concern.