Assessing the provisioning of multiple ecosystem services in semi-arid rangelands

Background/Question/Methods

Increasingly, dry rangelands are being valued for multiple services beyond their traditional value as a forage production system. Additional ecosystem services include the potential to store carbon in the soil and plant biomass. In addition, dust emissions from rangelands might be considered an ecosystem detriment, the opposite of an ecosystem service. Dust emitted may have far-reaching impacts, for example, reduction of local air quality as well as altering regional water supplies through negative effects on snowpack. Using an extensive rangeland monitoring dataset in Canyonlands National Park and the adjacent Dugout Ranch (Utah, USA), we developed a method to estimate indices of the provisioning of three ecosystem services (forage production, dust retention, C storage) and one ecosystem property (nativeness), taking into account both ecosystem type and alternative states within that ecosystem type. We also integrated these four indices into a newly developed multifunctionality index. This is a multiplicative index which inherently takes into account non-exchangeability of one type of function for another; poor functionality of any type generally leads to low multifunctionality.

Results/Conclusions

Comparing the currently ungrazed Canyonlands National Park watersheds to the adjacent Dugout Ranch pastures, we found clearly higher multifunctionality was attained in the Park, and that this was primarily driven by greater C-storage and better dust retention. It is unlikely that management can maximize all benefits and minimize all detriments at the same time. Some goods and services may have synergistic interactions; for example, managing for carbon storage will increase plant and biocrust cover likely lowering dust emission. On the contrary, some may have antagonistic interactions. For instance, if carbon is consumed as biomass for livestock production, then carbon storage may be reduced. If maximization of overall benefit to society is an ultimate goal, land managers and users should quantify the monetary consequences of specific land use practices for multiple ecosystem services. Such accounting may help maintain multiple ecosystem services, minimize economic detriments, and maximize economic benefits from multi-commodity rangelands. Our technique is the first step toward this goal, allowing the simultaneous consideration of multiple targeted ecosystem services and properties.