An ecosystem services approach to the quantification of shallow mass movement erosion and the value of soil conservation practices

This study characterises the loss of ecosystem services from a grazed pasture following shallow mass movement erosion and subsequent recovery of services. The influence of space-planted trees, a soil conservation practice, on the provision of services, was also assessed. The economic value of the services provided by an uneroded steep pasture grazed by sheep and cattle was estimated at NZD 3717 ha−1 yr−1. This value dropped by 65% when the topsoil was lost in a single shallow mass movement. Fifty years after erosion, the services only recovered to 61% of uneroded value. In contrast, the same landscape type planted with soil conservation trees provided, after 20 years, additional (+22% in dollar value) services from the similar unprotected landscape. A benefit cost analysis of soil conservation practices showed planting conservation trees is only profitable if the trees are harvested for timber (age 20), and low discount rates (<5%) are used. When the economic value of the extra services from conservation trees is included in the BCA, the Net Present Value of the investment is greatly positive at discount rates ranging from 0% to 10%. Analysis of this ecological infrastructure investment using an ecosystem service approach offers new insights for resource managers and policy makers.