An ecosystem services approach to the cost of soil erosion and value of soil conservation

Abstract

This paper reports on ecosystem services lost from a grazed pasture following a soil erosion event after a heavy rain storm which provoked landslides on hill slopes along a 250km coastal strip in the Hawke‟s Bay in April 2011. The study also characterises the recovery of the provision of ecosystem services in the years following the erosion event, as well as the influence the introduction of a space planted conservation tree would have on the provision of services from pasture soil. Finally the study explores how an ecosystem services approach can be used to inform a cost-benefit analysis of an ecological infrastructure investment in soil conservation and in decision making by policy. The total value of the ecosystem services provided by a typical sheep and beef farm was, for uneroded land, $5,085/ha/yr for rolling land and $3,717/ha/yr for steep land. The total value of the services provided by the bare ground of steep hills, following an erosion event, dropped by 64%. The recovery of ecosystems services after erosion stabilised after 50 years at approximately 61% (in dollar value) of uneroded levels. The presence of soil conservation trees increased the value of the services provided by 23%, 20 years after planting. The cost benefit analysis of soil conservation showed that planting trees isn‟t profitable unless the trees are harvested for timber, and low discount rates (<5%) are used. However, when considering the value of the extra provision of ecosystem services, the Net Present Value of the investment is greatly positive regardless of the discount rate (0-10%).This study addresses a real-world conservation issue and shows how an ecosystem services approach can be integrated and used on the ground to advance existing governance frameworks and inform resource management challenges.