Submitted to: Ecohydrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/9/2016
Publication Date: 4/10/2017
Publication URL: https://handle.nal.usda.gov/10113/6472375
Citation: Sanches Oliveira, P., Leite, M., Mattos, T., Nearing, M.A., Scott, R.L., Oliveira Xavier, R., Da Silva Matos, D., Wendland, E. 2017. Groundwater recharge decrease with increased vegetation density in the Brazilian cerrado. Ecohydrology. 10:e1759. https://doi.org/10.1002/eco.1759.
DOI: https://doi.org/10.1002/eco.1759

Interpretive Summary: The Brazilian Cerrado is considered one of the most important Brazilian biomes, covering an area of 2 million km2, and is the second largest biome in South America after the Amazon. The physiognomies of the Cerrado vary from grassland to savanna to forest. Because of its endemic plant and vertebrate species, this biome has been classified as one of the 25 global biodiversity hotspots. Drought has been a big problem in this region of Brazil in recent years, and since much of the water source is from groundwater, recharge of aquifers is an important topic now for Brazil. The objective of this study was to assess groundwater recharge in different physiognomies of the Brazilian Cerrado. We also investigated how recharge rates can change with the density of vegetation, and the possible consequences of the Cerrado deforestation on groundwater recharge. We concluded that recharge tends to decrease with the increase in the density of vegetation (grassland to woodland). Also, the recharge rates reported here represent the first ranges of values for undisturbed cerrado physiognomies and thereby can be useful for predictions for future distributions of grassland, savanna and forest biomes under changing climate.

Technical Abstract: Approximately one half of the outcrop areas of the Guarani Aquifer System (GAS) are located in the Cerrado biome, the main agricultural expansion region in Brazil. Large areas of cerrado vegetation have been converted into farmland in recent years; however, little attention has been paid to the consequences of this land use and land cover change on groundwater recharge. Here we assessed groundwater recharge in different physiognomies of the cerrado located in an outcrop area of the GAS. Water table fluctuations were measured from October 2011 through August 2013, by 58 monitoring wells distributed on four physiognomies of the undisturbed cerrado. We used multiple monitoring wells located in "campo limpo" (cerrado grassland), "campo sujo" (shrub cerrado), "campo cerrado" (shrub cerrado), and "cerrado sensu stricto" (wooded cerrado), cover types. Recharge rates were computed for each well using the Water Table Fluctuation method. The measured precipitation for hydrological years 2011-12 and 2012-13 were 1247 mm and 1194 mm, respectively. We found values of average annual recharge of 363±87 mm, 354±85 mm, 324±78 mm, and 315±76 mm for "campo limpo", "campo sujo", "campo cerrado", and "cerrado sensu stricto", respectively. Our results suggest that recharge tends to decrease with the increase in the density of vegetation (grassland to woodland). These results indicate that water table depth may have an influence on the Cerrado physiognomies or vice versa. Furthermore, replacement of undisturbed dense cerrado with croplands will likely alter recharge dynamics. Therefore, sound management of land use and land cover is needed to ensure future groundwater quantity and quality.