Water table fluctuation and its effects on vegetation in a semiarid environment

Abstract

A good understanding of water table fluctuation effects on vegetation is crucial for sustaining fragile hydrology and ecology of semiarid areas such as the Horqin Sandy Land (HSL) in northern China, but such understanding is not well documented in literature. The objectives of this study were to examine spatio-temporal variations of water table and their effects on vegetation in a semiarid environment. A 9.71 km<sup>2</sup> area within the HSL was chosen and well-instrumented to continuously measure hydrometeorologic parameters (e.g., water table). The area comprises of meadow lands and sandy dunes as well as transitional zones in between. In addition to those measured data, this study also used Landsat TM and MODIS imageries and meteorological data at a station near the study area. The spatio-temporal variations were examined using visual plots and contour maps, while the effects on vegetation were determined by overlaying a water table depth map with a vegetation index map derived from the MODIS imageries. The results indicated that water table was mainly dependent on local topography, localized geological settings, and human activities (e.g., reclamation). At annual and monthly scales, water table was mainly a function of precipitation and potential evapotranspiration. A region within the study area where depth to water table was smaller tended to have better (i.e., more dense and productive) vegetation cover. Further, the results revealed that water table fluctuation was more sensitive for vegetations in the meadow lands than in the transitional zones, but it was least sensitive for vegetations in the sandy dunes

Impact of Water-Level Fluctuation in Redhills Reservoir on Population Dynamics of Chennai City

“…The High population and necessarily of water is needed may be the causes. these findings also supported by Tamar Zohary and Ilia Ostrovsky, droughts with declining river inflows over the region have led to a multiannual drawdown of its water level [23]. In addition to drawdown and other forms of water exploitation, climate change models predict increased occurrence of extreme events such as flooding and extended droughts [24], which will further magnify the seasonal and multiannual amplitude of WLF in lakes and alter their temporal dynamics [25].…”

Precipitation and Water Table Dynamics in Peat Swamp Catchment in Sarawak, Malaysia

“…Monthly data for each site were used for analysis. Monthly WT is defined as the arithmetic mean of WT recorded by the water level logger for a month [27]. Gaps in monthly WT data (due to equipment malfunction or corrupted data files and data that has been screened for outliers) were filled using in-situ measurements of WT, which are also recorded every month during fieldwork at the sites.…”

Berenty Reserve—A Gallery Forest in Decline in Dry Southern Madagascar—Towards Forest Restoration

“…In flood years the river can top its banks and flow over a meter deep across the forest floor (Figures 2 and 9) and although recurrent droughts can be disastrous for lemurs [13], droughts in terms of gallery forest survival are normal. In order to survive, many of the tree species have deep taproots, so that even when the river dries completely their roots can reach the saturated zone below the water table [39].…”