Enhancing Ecosystem Services to Minimize Impact of Climate Variability in a Dry Tropical Forest with Vertisols

Abstract

Increased droughts and variable rainfall patterns may alter the capacity to provide ecosystem services, such as biomass production and clean water provision. The impact of these factors in a semi-arid region, especially on a dry tropical forest with Vertisols and under different land uses such as regenerated vegetation and thinned vegetation, is still unclear. This study analyzes hydrologic processes under precipitation pulses and intra-seasonal droughts, and suggests management practices for ecosystem services improvement. A local 43-year dataset showed a varying climate with a decrease in number of small events, and an increase in the number of dry days and in event rainfall intensity, in two catchments with different land use patterns and with Vertisols, a major soil order in semi-arid tropics. The onset of runoff depends on the expansive characteristics of the soil rather than land use, as dry spells promote micro-cracks that delay the runoff process. Forest thinning enhances groundcover development and is a better management practice for biomass production. This management practice shows a lower water yield when compared to a regenerated forest, supporting the decision of investing in forest regeneration in order to attend to an increasing water storage demand.

Canopy Effects on Rainfall Partition and Throughfall Drop Size Distribution in a Tropical Dry Forest

“…The total event rainfall varied from 0.42 to 116.70 mm (Table 3), evidencing the high variability of rainfall in the region (Figure 4). The highest frequency of occurrence (48%) was recorded for events with a total rainfall below 5.0 mm (Table 3 and Figure 4)-the high occurrence of small rainfall events and high temporal variability are characteristics of tropical semi-arid regions of low latitude [22,33,42]. For more information on the contribution of low rainfall events to the understanding of the hydrological processes, see the research [5,43] in a tropical semi-arid region of low latitude.…”

“…The dry period occurs from June to December, with only 1% of the total annual rainfall [22], showing the high temporal variability of rainfall [28,30]. The annual potential evapotranspiration surpasses 2000 mm, which is within the 0.2 and 0.5 rainfall-to-potential evapotranspiration ratio described by [31] for semi-arid regions and has an aridity index of 0.48 [32] that also classifies the region as semi-arid, where water scarcity is observed 9 to 10 months per year [33].…”

Climate Data to Predict Geometry of Cracks in Expansive Soils in a Tropical Semiarid Region

“…The historical mean annual rainfall of the region is 997 ± 300 mm, of which 89% is concentrated in the period from December to May [15]. The average potential evaporation is 2113 mm year -1 , with an aridity index of 0.48 [16].…”

Strategies for Improving Water Use Efficiency in Dryland Agroecosystems

“…However, many of the assumptions about drylands turn out to be unfounded. For example, some drylands in equatorial Africa receive more than 1000 mm of rainfall per year, but often suffer from prolonged dry seasons and high mean temperatures, leading to high rates of water loss through transpiration and evapotranspiration [1] . Low soil moisture and high atmospheric water demand are the two main driving forces threatening agroecosystems.…”

“…Rainfall patterns, erosive winds and high temperatures pose the greatest risks to dryland agroecosystems. Most dryland agroecosystems face climatic uncertainty, and annual precipitation can vary from well above and to well below the 50% mean throughout the year, which can cause hydrological imbalance [1] . Rainfall intensity and the number of dry days increased from 1974 to 2017 in tropical drylands of Iguatu, Brazil, aggravating the already dry characteristics of the region and contributing to more extreme runoff events [2] .…”