Integrating systematic conservation planning and ecosystem services : an indicators approach in the Hill Country of Central Texas

Ecosystem services are the aspects of the environment utilized to produce human well-being and are key elements of landscape sustainability. Increasingly, measures of ecosystem services are being incorporated into conservation decision making. However, a framework for evaluating systematic conservation planning ranked selection scenarios with indicators of ecosystem services has not been developed. Using the Central Texas counties of Blanco, Burnet, Hays, Llano, San Saba, and Travis as a study, a suite of spatially explicit modeling tools, Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST), are used to quantify carbon storage, soil conservation, and water provision. A fourth service metric, ecosystem richness, is derived using Texas Parks and Wildlife ecological systems classification data. The values of these four services are then used to evaluate four conservation scenarios, developed in conjunction with a local conservation non-profit, Hill Country Conservancy (HCC), and derived using Marxan decision-support software.
The evaluation process consists of both geographic information system (GIS) and statistical analysis. GIS based overlay analysis is used to identify areas of multiple ecosystem service overlap. Spearman correlation tables are used to test the spatial relationship among ecosystem services, as well as the relationship among each of the four conservation scenarios. Wilcox-Mann-Whitney U tests (WMW) are used to assess the statistical significance of each scenario’s ecosystem service values as compared to the values of a random control scenario.
The results of this work reinforce the findings that there is often significant variability in the spatial congruence of multiple ecosystem services and their provision across a landscape. This work also supports the conclusion that the targeting of ecological phenomena for conservation concurrently targets areas supporting multiple ecosystem services. More distinctively, the results verify the capacity of ecosystem service indicators to effectively inform an iterative systematic conservation planning process. At the local landscape-scale, this work provides HCC with defensible support of their conservation decisions based not only on organizational priorities, but also on ecosystem service values. More broadly, this work provides a framework for evaluating conservation scenarios with spatially explicit values of ecosystem services which can be replicated across a wide range of project scales and objectives.