TY - JOUR

T1 - Forest regeneration can positively contribute to local hydrological ecosystem services: implications for forest landscape restoration

AU - van Meerveld, Ilja

AU - Jones, J.P.G.

AU - Ghimire, Chandra P.

AU - Zwartendijk, B. W.

AU - Lahitiana, Jaona

AU - Ravelona, Maafaka

AU - Mulligan , Mark

N1 - Natural Environment Research Council. Grant Numbers: NE/K010220/1, NE/K010417/1

PY - 2021/4

Y1 - 2021/4

N2 - Governments are increasingly committing to significant forest restoration. While carbon sequestration is a major objective, the case for restoration often includes benefits to local communities. However, the impacts of forest restoration on local hydrological services (e.g. flood and erosion risk, stream flow during dry periods) are surprisingly poorly understood. Particularly limited information is available on the impacts of passive tropical forest restoration following shifting cultivation.The outcome depends on the trade‐off between the improved soil infiltration capacity (reducing overland flow and increasing soil and groundwater recharge) and greater evapotranspiration (diminishing local water availability).Using measurements from highly instrumented plots under three vegetation types in the shifting cultivation cycle in Madagascar's eastern rainforests (forest, tree fallow and degraded abandoned agricultural land), and infiltration measurements for the same vegetation types across the landscape, we explore the impacts of forest regeneration on the ecohydrological processes that underpin locally important ecosystem services.Overland flow was minimal for the tree fallow (similar to the forest) and much lower than for the degraded land, likely leading to a lower risk of erosion and flooding compared to the degraded land. Conversely, evapotranspiration losses were lower for the tree fallow than the forest, leading to a higher net recharge, likely resulting in more streamflow between rainfall events.These results demonstrate that young regenerating tropical forest vegetation can positively contribute to locally important hydrological ecosystem services. Allowing tree fallows to recover further is unlikely to further reduce the risk of overland flow but may, at least temporarily, result in less streamflow.Synthesis and applications. Encouraging natural regeneration is increasingly seen as a cost‐effective way to deliver forest landscape restoration. Our data suggest that increasing the abundance of young secondary forest in the tropics, by increasing fallow lengths in the shifting cultivation cycle, could make a positive contribution to locally important hydrological ecosystem services (specifically reducing overland flow and therefore erosion and flooding, while maintaining streamflows). Such empirical understanding is needed to inform the models used for planning forest landscape restoration to maximize benefits to local communities.

AB - Governments are increasingly committing to significant forest restoration. While carbon sequestration is a major objective, the case for restoration often includes benefits to local communities. However, the impacts of forest restoration on local hydrological services (e.g. flood and erosion risk, stream flow during dry periods) are surprisingly poorly understood. Particularly limited information is available on the impacts of passive tropical forest restoration following shifting cultivation.The outcome depends on the trade‐off between the improved soil infiltration capacity (reducing overland flow and increasing soil and groundwater recharge) and greater evapotranspiration (diminishing local water availability).Using measurements from highly instrumented plots under three vegetation types in the shifting cultivation cycle in Madagascar's eastern rainforests (forest, tree fallow and degraded abandoned agricultural land), and infiltration measurements for the same vegetation types across the landscape, we explore the impacts of forest regeneration on the ecohydrological processes that underpin locally important ecosystem services.Overland flow was minimal for the tree fallow (similar to the forest) and much lower than for the degraded land, likely leading to a lower risk of erosion and flooding compared to the degraded land. Conversely, evapotranspiration losses were lower for the tree fallow than the forest, leading to a higher net recharge, likely resulting in more streamflow between rainfall events.These results demonstrate that young regenerating tropical forest vegetation can positively contribute to locally important hydrological ecosystem services. Allowing tree fallows to recover further is unlikely to further reduce the risk of overland flow but may, at least temporarily, result in less streamflow.Synthesis and applications. Encouraging natural regeneration is increasingly seen as a cost‐effective way to deliver forest landscape restoration. Our data suggest that increasing the abundance of young secondary forest in the tropics, by increasing fallow lengths in the shifting cultivation cycle, could make a positive contribution to locally important hydrological ecosystem services (specifically reducing overland flow and therefore erosion and flooding, while maintaining streamflows). Such empirical understanding is needed to inform the models used for planning forest landscape restoration to maximize benefits to local communities.

KW - forest and landscape restoration

KW - forest hydrology

KW - forest restoration

KW - Madagascar

KW - rain forest

KW - Reforestation

KW - secondary forest

KW - slash-and-burn

U2 - 10.1111/1365-2664.13836

DO - 10.1111/1365-2664.13836

M3 - Article

VL - 58

SP - 755

EP - 765

JO - Journal of Applied Ecology

JF - Journal of Applied Ecology

SN - 1365-2664

IS - 4

ER -