Alternative ecosystem regimes as a guide to economically sustainable restoration

Abstract

Degraded land cannot be easily restored everywhere at acceptable cost. Thus, decisions are required on where and when best to invest in restoration. Particularly, the presence of alternative ecosystem regimes matter greatly for financial viability of investments, as does the opening of an ecological window of opportunity (e.g. very wet period). Here, we present a decision-support tool based on dynamic ecosystem regimes to guide economically sustainable restoration. It explicitly considers degradation severity, hysteresis thresholds and suitable management timings. Applying this tool to Mediterranean rangelands, we assess discounted investment and maintenance costs as well as benefits (e.g. pasture productivity and cover) dependent on stability domains and windows of opportunities. Results demonstrate greater chance of success and higher returns on investment in a bi-stable domain when interventions (e.g. seeding, manuring) coincide with a climate window of opportunity. When investments are insufficient for an ecosystem to cross a threshold, costs to maintain the achieved improvement are incurred while waiting for a new window of opportunity. Our decision-support tool is widely applicable and enables the development of generic restoration principles. It provides a new way of analysing costs and benefits of action and inaction, allowing land managers to focus their restoration and monitoring efforts on situations for which they are likely to have the greatest effect.