Effects Of Urbanization On Plant Phenology In Hohhot, Inner Mongolia

Urbanization has profound environmental impacts at a multitude of scales, primarily due to land use/cover transformations. At the local scale, the widespread of impervious surfaces and low vegetation cover in cities have led to phenology differences between urban and rural areas. However, there are not too many researches in the Inner Mongolia area. In addition, most of them are based on phenological models to study the relationship between meteorological data and phenology in a long time series and lack of spatial analysis. We monitored spring phenology of Populus alba L.var. pyramidalis Bunge, P. cathayana Rehd, P. tomentosa Carr, Rhus typhina Nutt, Prunus davidiana and Salix babylonica at different sites across the urban and in the surrounding rural area of Hohhot city in Inner Mongolia, together with air temperature measured by data loggers during two growing seasons. We also did interpretation of remote sensing data using the software of eCognition9.2and ArcGIS9.3. The relationship between temperature, Urban index (UI) and phenology were analyzed. Our results reveal the following patterns:1.The timing of spring phenophases was best predicted by the average of10-20day mean daily temperature and accumulated growing degree days temperature that above5degree centigrade (AGDD5), mean and minimum daily temperature of April; autumn phenophases was best predicted by the mean and minimum monthly temperature of August to October.2.the Urban Index were significantly negatively correlated with the April to October mean and minimum daily temperatures, accumulated growing degree days temperature that above5degree centigrade (AGDD5), positively correlated with the spring phenophases of the above trees. Spatially, the spatial pattern were similar between urban index, spring phenophases of populars, and mean, minimum and maximum daily temperature of April also with the accumulated growing degree days temperature that above5degree centigrade (AGDD5) of May.We conclude that urbanization in the form of changing land use/cover context, in general advances spring phenophases and delays autumn phenophases by significantly influencing patterns of temperature, the primary environmental driver of phenology. Our study of the rapidly urbanizing area of Inner Mongolia provides comprehensive and important information for scientists and practitioners engaged in understanding effects of urbanization in the Inner Mongolia area.