Assessing the Freshwater Conservation Potential of Terrestrial Protected Areas

Abstract

Physical alteration, habitat loss, water withdrawal, pollution, land use change, overexploitation, and the introduction of nonnative species together negatively influence freshwater ecosystems. Due to these stresses, freshwaters are ranked among the most at risk systems worldwide (Malmqvist and Rundle, 2002). Protected areas (PAs), defined as an area of land and/or sea especially dedicated to the protection and maintenance of biological diversity as well as natural and associated cultural resources and managed through legal or other effective means (IUCN, 1994), are an emerging tool for the protection of biodiversity and natural resources. Despite the well‐documented threatened status of freshwater ecosystems, terrestrial targets have received far more attention and resources in the designation of PAs (Abell et al., 2007). However, because many terrestrial PAs include freshwater components, use fluvial systems as borders, or affect freshwaters downstream, it is important to understand the role that terrestrial PAs play in freshwater conservation (Abell et al., 2007; Herbert et al., in press). The goal of our study was to investigate the conservation potential of terrestrial PAs. As such, using Federal‐ and Stateowned PAs within the Northern Lake Michigan, Lake Huron, and Straits of Mackinac Ecological Drainage Unit of the State of Michigan (TNC, 2001), we evaluated two broad attributes of PAs: (1) the effect of containing land in an undeveloped condition on downstream freshwater key environmental attributes (KEAs: biotic composition, connectivity, hydrologic regime, physical habitat and energy regime, and water quality), and (2) the ability of managers to identify and mitigate negative anthropogenic influences on KEAs. Our first objective was to determine the effect of total area under protection by terrestrial PAs on KEAs. To do so, data was collected on eight response variables representative of the five KEAs which included: NO2 + NO3 concentration, total phosphorus concentration, free flowing stream miles, average rate of flow response, low flow expectation, habitat quality score, fish index of biotic integrity, and percent of fish considered intolerant to anthropogenic stress. Next, using Geographic Information Systems (GIS), catchments derived from individual response variable datum locations were delineated and the total percent of land in protection within each catchment was calculated. Finally, the relationship between response variable values and percent land protected was determined using linear regressions. We found significant (p<0.05) decreases in NO2 + NO3 concentration and average rate of flow response with increasing area of catchment in protection, suggesting that by keeping land in a natural state, PAs can contribute to lowering nitrogen concentrations and reducing stream flashiness downstream. We also found significant increases in the percent of fish considered intolerant to anthropogenic stress with increasing area of catchment in protection, suggesting PAs may contribute to

enhancing the total number of environmentally sensitive fish. No significant relationship was found between PAs and total phosphorus concentration, free flowing stream miles, low flow expectation, habitat quality score, or fish index of biotic integrity. Our second objective was to determine how PA management attends to freshwater conservation. To do so, we randomly selected eleven Federal‐ and State‐owned PAs located within the Northern Lake Michigan, Lake Huron, and Straits of Mackinac Ecological Drainage Unit of the State of Michigan and conducted PA management questionnaires and interviews, based on IUCN’s “Evaluating Effectiveness: A Framework for Assessing Management of Protected Areas” guidelines (Hockings et al., 2006) and the principles of integrated water resource management (IWRM; Global Water Partnership, 2009). This process identified what PA managers perceived to be greatest internal (within PA) and external (outside of PA) threats to freshwater KEAs within PAs and what specific activities PA managers conducted to protect or restore KEAs. The alignment between threats and activities was then determined as a measure of management’s attendance to freshwater conservation. This analysis revealed that management processes are, with a few exceptions, complementary to identified threats to freshwater systems. However, while our findings suggest positive alignment between management activities and identified threats, the informality of collaborative processes and absence of robust freshwater monitoring programs indicate that management is not fully engaged in IRWM, which limits the capacity for adaptive management. Our third objective was to determine the relative influences of management and catchment stressors on KEAs. Using previously delineated response variable catchments, we organized response variable values by the study PAs contained within their catchments, and calculated PA‐specific response variable scores (Response Variable Score). Next, using the same response variable catchments, we calculated a measure of catchment condition (Catchment Condition Score). Finally, using results from PA management questionnaires, we quantified the degree of activity potentially affecting KEA response variables (Management Activity Score). Catchment Condition Scores and Management Activity Scores were then compared to Response Variable Scores to identify instances where PA management activities were successful in mitigating the effects of catchment stressors on KEAs (Scenario 1) and instances where catchment stressors had an overriding effect on management activities (Scenario 2). The two Scenarios were observed in nearly identical proportions across KEAs and PAs, suggesting that both management activities and catchment stressors vary in their ability to affect freshwater KEA values. However, Scenario 1 was observed more than Scenario 2 for water quality, while the opposite was observed for biotic composition and hydrologic regime, suggesting management activities may be more successful in mitigating the effects of catchment stressors specific to nutrient concentrations. Our results suggest that terrestrial PAs likely contribute to some components of freshwater KEAs by protecting land from development and through certain management activities. However, further research is warranted to more extensively track the effect of the interaction of anthropogenic stressors and management activities on freshwater systems. If terrestrial protection were sufficient to secure freshwater integrity, we would expect the majority of indicators to be favorably related to total percent protected. Since only three of eight response variables showed the expected relationship, our findings do not support the assumption that watershed protections are synonymous with maintenance of freshwater KEAs. Our approach provides a framework for evaluating and tracking key freshwater outcomes while addressing the interacting factors of human‐induced stress and management attempts to mitigate these stresses. Furthermore, our approach holds utility for any managing entity attempting to produce favorable outcomes for freshwater systems. Future applications of this approach can be tailored to include a different set of management activities, catchment stressors, and response variables, depending on the context of the PA and what data are available for use.