Environmental factors affecting mortality rate of Sapria himalayana Griff.

Abstract

The study of environmental factors affecting mortality rate of Sapria himalayana Griff. in Queen Sirikit Botanic Garden (Huai Phihlok), Mae Rim district, Chiangmai, Doi Suthep-Pui National Park (Doi Suthep) and Huai Khok Ma (Huai Khok Ma), Muang, Chiangmai were conducted between August 2015 – July 2016. Three plots of 100 x 100 square meters were located for data collections. Then, random five host plants in each plots of 5 x 5 square meters were randomly sampled to collect ten environment factors. S. himalayana Griff. population were measured every two weeks all year round. The results showed that the highest mortality rate found in March at Huai Khok Ma and December at Doi Suthep and Huai Phi Hlok as 74%, 80% and 75%, respectively. Furthermore, the result of principal component analysis (PCA) indicated that the S. himalayana Griff. population of three sites had the negative correlation with the soil temperature, air temperature and light intensity inside the plots. The result shows that the temperature affects the mortality rate. On account of the increased mortality rate, the temperature was decreased.