The phenology of the Enkangala Grasslands

Abstract

Phenology is the study of the timing within the year of life history events in plants and animals. The phenology of plants is usually cued to climate; therefore climate change is likely to have an effect on the date of events such as greening and browning and thus the length of the growing season. Since the growth duration, the rainfall and the temperature all control primary productivity and transpiration, phenological change will lead to changes in the ecosystem services of forage provision and water yield. Remote sensing techniques are used to describe the grassland phenology at landscape scale in the high-altitude Enkangala grasslands of South Africa over a period of 18 years, using an ecologically-based phenological model, in which the parameters were related to climatic cues. A 100year daily climate data record is then used to hindcast the grassland phenology over the 20th century and test for changes. Finally, possible future phenological trends are made based on climate change projections for the region. We found that the length of the growing season has not increased over the 18 year period but it has increased by 35 days over the past 100 years. This is due to the growing season starting at an earlier date than usual and ending at a later date.