Using headwater streams and salamanders to test hypotheses of golf course impacts

Background/Question/Methods

With more than 18,000 golf courses in the U.S. encompassing over 2.7 million acres, golf has become a significant land use. The purpose of this study was to examine the impacts of golf course management on stream habitat and water quality and to specifically examine the influence of golf management on stream salamander communities. We tested the following hypotheses about the effects of golf course management on streams: golf courses 1) produce chemical runoff which affects stream salamander communities directly downstream of courses, 2) cause direct habitat alteration which affects stream salamander communities on golf courses, 3) cause indirect habitat alteration which affects stream salamanders directly downstream of golf courses. We measured relative abundance and diversity of larval and adult stream salamanders in 60 stream reaches located upstream, on, and downstream of 10 golf courses in western North Carolina. We also measured 13 biologically relevant riparian and in-stream habitat characteristics to better understand the impacts of management on habitat quality. We made predictions about direct (on course) and indirect (downstream) effects for each habitat variable. We also measured nitrate and pesticide levels upstream and downstream of courses to test the chemical runoff hypothesis.

Results/Conclusions

Salamander abundance and diversity did not differ in streams located upstream and downstream of golf courses. Stream reaches on managed portions of golf courses on average contained lower salamander abundances and diversity for adults and larvae, though only larval diversity was significant. Nitrate was not detected at any of the stream reaches and only two of the 16 pesticide chemicals screened for were detected in negligible proportions. On average none of the 13 habitat variables measured differed in upstream and downstream reaches. Six of these variables were significantly altered in the on-course streams. Overall our chemical, salamander, and habitat results did not support the chemical runoff hypothesis or the indirect habitat alteration hypothesis. Our findings of altered habitat characteristics and lowered larval salamander diversity in on-course streams provide support for the direct habitat influence hypothesis. This study provides a useful starting point for understanding the current impacts of golf course management on stream habitat and water quality, and provides a directed transition into the next step of experimental habitat manipulation for stream biodiversity enhancement.