Mimicking nature to reduce agricultural impact on water cycles: A set of mimetrics

Abstract

Metrics of hydrological mimicry (‘mimetrics’) reflect similarity in ecological structure and/or functions between managed and natural ecosystems. Only the land-surface parts of hydrological cycles are directly visible and represented in local knowledge and water-related legislation. Human impacts on water cycles (HIWC) can, beyond climate change, arise through effects on local and regional hydrological processes, from both reduced and increased water use compared to a natural reference vegetation with which landscape structure and hydrology are aligned. Precipitationsheds, the oceanic and terrestrial origin of rainfall, depend on evapotranspiration and thus on vegetation. The political commitment to reduce agricultural impact on nature requires hydrological mimetrics to trickle down through institutions to actions. Existing metrics do not suffice. For example, the water footprint metric that relates agricultural water use to consumption decisions, suggests minimizing water use is best, ignoring full hydrological impacts. We explore principles, criteria and indicators for understanding HIWC, via modified evapotranspiration, effects on streamflow (downstream impacts) and atmospheric fluxes and precipitation (downwind impacts). Comprehensive HIWC mimetrics for a set of pantropical watersheds suggest hydrological mimicry options for forest-derived land use patterns through intermediate densities of trees with diversity in rooting depth and water use, interacting with soils, crops and livestock.

UAV-based thermography reveals spatial and temporal variability of evapotranspiration from a tropical rainforest

“…Further, by expanding the applicability of the DATTUTDUT model to a more complex ecosystem, it may facilitate landscape-scale assessments of ET including various land covers. Given the large potential and need for ecosystem restoration in rainforest regions, our study can provide reference information from near-natural vegetation regarding ET from the Harapan forest which is a large-scale (≈ 100,000 ha) ecosystem restoration area (Harrison and Swinfield, 2015;Brancalion et al, 2019;van Noordwijk et al, 2022). In this context, assessments of ET and its variability in tropical rainforests are of particular importance to narrow persisting observation and knowledge gaps in thus far underrepresented ecosystems.…”

Carbon footprints, informed consumer decisions and shifts towards responsible agriculture, forestry, and other land uses?

“…Among the various components of the ecological footprints, the water footprint [52] may well be most compelling as the combination of increased demand for reliable, clean water coincides with more variable climates in which both drought and floods are a risk, and a diminished capacity of landscapes to buffer water flows [53] . Water footprints normally include the use of "blue" water (surface or groundwater), direct use of rainfall buffered in soils "green" water, and a "grey" water component (how much clean water is needed to dilute pollution to acceptable standards).…”