The summer phenological changes and its responses to weather factors, in case of Hustai National Park of Mongolia
Recently, the grassland ecosystems have been experienced climate change and overgrazing by livestock. Negative effects of climate change on the grassland ecosystems have been reported as well as social and economic aspects of Mongolian nomadic herders. It is getting urgent need to know responses of plants to climate change. Stipa species dominated communities are one of the main vegetation types of grassland ecosystems covering 86% of the total area of Mongolia. In the arid and semi-arid grassland ecosystem of Mongolia, phenology of plant species are very sensitive to inter-annual and intra-annual variability in weather factors because there is high dependency of plant growths on climatic factors in the ecosystems. Climate change affecting strong influences to vegetation community structure and plant phenology. With the purpose to understand phenological alteration of Stipa species as a consequence of climate change, we monitored phenological phases S. krylovii, and S. klemenzii including sprouting, flowering, development of fruits, ripening of fruits and senescence beginning of dormancy in four permanent plots representing main vegetation types in Hustai National Park, Mongolia.
Here we shows some preliminary results of phenology of Stipa genus of Eurasian grasslands. Stipa klemenzii Roshev., Stipa krylovii Roshev. dominant species were in steppe and mountain steppe which is common land cover type of Hustai national park and Mongolian grassland. Results of regression analysis shows significant correlation (P<0.027) between precipitation of May, June and beginning of growing season of S. klemenzii. The beginning of budding and flowering periods of S. klemenzii depend on air temperature of July and August with P<0.0207, P<0.001, respectively. The length of growing season period depends on air temperature of September (P<0.04). The result of S. krylovii significant correlation (P<0.026) between air temperature of May and June and beginning of growing season. The beginning of budding and flowering periods depend on precipitation of July and August with P<0.006, P<0.001, respectively. During the 2003-2014, we found increasing trends of the lengths of growing seasons (Mann-Kendall, P<0.0282). In this study, we identified positive relationships between precipitation and the beginning of growth seasons. Contrary, timing of budding and flowering periods more depends on air temperature of July and August. The end of growing seasons positive responses to air temperature.