Water budget and run‐off response of a tropical multispecies “reforest” and effects of typhoon disturbance

Abstract

To examine claims that reforesting degraded Imperata grassland in Leyte (Philippines) made streamflow perennial again, we studied the hydrological behaviour of a 23‐year‐old mixed‐species “reforest” between June 2013 and May 2014. Typhoon Haiyan, one of the strongest events ever, caused major damage to the site in November 2013. Average daily apparent water use (ET) was 5.0 mm day−1 pretyphoon and 3.2 mm day−1 after disturbance. Corresponding ratios of period total quickflow Qq to precipitation were 16% and 44%. Quickflow volume and peak discharge increased rapidly once a threshold value of ~250 mm for soil water storage in the top 60 cm was exceeded. Before disturbance, quickflow consisted predominantly of lateral subsurface flow due to high soil hydraulic conductivities down to 60 cm. After disturbance, shallow groundwater rose regularly to within 10 cm of the surface on foot slopes, and saturation overland flow was observed during several large storms. Comparing estimated annual ET and Qq for undisturbed conditions for the reforest and a nearby degraded Imperata grassland microcatchment suggested that the extra infiltration following reforestation (~240 mm year−1) exceeded the extra ET by the reforest (100–185 mm year−1), implying a net positive trade‐off (55–140 mm year−1) and tentatively confirming local claims of improved dry‐season flow.

Characterization of sudden and sustained base flow jump hydrologic behaviour in the humid seasonal tropics of the Panama Canal Watershed

“…Krishnaswamy et al () examined the groundwater recharge response and hydrologic services on evergreen tropical forests and degraded tropical forest ecosystems in western India. Their results supported the “infiltration–evapotranspiration trade‐off” hypothesis that the differences in infiltration between land covers controlled the differences in groundwater recharge and dry‐season flow (Bruijnzeel ) Zhang, Bruijnzeel, Tripoli, and van Meerveld () explored the ecological and hydrological functioning of a “reforested” tropical catchment and found that forest development over two decades had caused streamflow to become perennial through markedly improved infiltration opportunities (Zhang et al, ). These results highlighted the importance of climatic as well as terrain factors, such as catchment slope and land covers, in controlling groundwater recharge and base flows.…”

Modeling the Joint Effects of Vegetation Characteristics and Soil Properties on Ecosystem Dynamics in a Panama Tropical Forest

“…Furthermore, not only soil properties affect the plant composition/diversity, but tropical forests also tend to modify these properties of soil (Zhang et al., 2018, 2019; Zinke, 1962), which generates important plant‐soil feedbacks (Kulmatiski et al., 2008). More field and experimental efforts are needed to gain a better understanding of the hydrology‐vegetation feedback mechanisms to explain and maintain species diversity in tropical forests (Sollins, 1998).…”

Near‐surface water fluxes and their controls in a sloping heterogeneously layered volcanic soil beneath a supra‐wet tropical montane cloud forest (NW Costa Rica)

“…Amounts of Q s (in mm) for individual events were linked to corresponding amounts of incident precipitation (P g ), and to the sum of P g and antecedent soil moisture content (ASMC, in mm) for the first 30 cm to detect possible threshold values of P g and/or (P g + ASMC) for stormflow generation (Tromp-van Meerveld & McDonnell, 2006b;Zhang et al, 2019). Before statistical analysis, the data were checked for normality using the non-parametric Kolmogorov-Smirnov test.…”

“…Reflecting the complex interactions between the numerous factors and processes governing soil moisture dynamics, the relationship between soil moisture content and stormflow amount is usually non‐linear (Penna et al, 2015; Zabaleta & Antigüedad, 2013; Zehe & Blöschl, 2004). In addition, this relationship often exhibits threshold‐type behaviour (Crow et al, 2018; Detty & McGuire, 2010; Fu et al, 2013; Graham et al, 2010; Tromp‐van Meerveld & McDonnell, 2006b; Zhang et al, 2019).…”