How far surface water fluxes determine restoration success in Mediterranean degraded areas? Implications for dryland precision restoration

Abstract

Drylands functioning depends on water fluxes and the retention of resources. The restoration of degraded areas should mimic the natural arrangement of vegetation in the landscape in a source-sink pattern. Reintroducing key woody seedlings through planting is a major concern in ecological restoration as these areas often exceed degradation thresholds and ecosystem functions are limited. However, it is not clear how natural fluxes might determine seedlings performance of key woody species. We have analyzed the microcatchment surface area of planting spots with and without water optimization treatment (waterproof surfaces with dry wells) and the survival and growth of Olea europaea seedlings during six years after planting in a semiarid degraded landscape. We recorded a positive effect of water optimization treatment in seedling survival and growth highlighting water limitation of these sites. We did not observe a clear and linear relationship between microcatchment collecting surface area and plant performance. The higher the collecting surface the lower the retention capacity of the planting pitch suggesting a loss of the integrity of the planting hole structure. Water optimization treatments were especially effective when collecting surface areas were low. These results might be useful for designing precision restoration actions in degraded landscapes.