Instream bacteria as a low-threshold management indicator of tourist impacts in conservation reserves

National parks, World Heritage areas and other conservation reserves protect biological diversity and provide clean water, Most jurisdictions also permit recreation in reserve areas. In some countries, tourism may contribute to the establishment and maintenance of reserves. The use of reserves for individual and commercial tourism and recreation is increasing very rapidly worl­wide. The ecological impacts of this use, and the resources required to manage those impacts, are increasing correspondingly. Quantitative monitoring data on the types, extent and degree of such impacts, in relation to the types, timing and intensity of tourist activities, are hence vital, in order to manage reserves for their primary conservation purpose. Most importantly, reserve managers need early-warning indicators of tourist impacts, before those impacts reach the threshold of irreversible damage. Different types of impact have different relative significance in different ecosystems. Trampling by hikers does less lasting damage to vegetation in mesic than extreme environments, but weed seeds and fungal spores are more likely to establish. Human voices are a major disturbance to fauna in subtropical rain­forest, but not on snowcapped mountaintops. Human wastes can cause a far greater increase in nutrient concentrations in small alpine ponds or desert waterholes than in higher-National parks, World Heritage areas and other conservation reserves protect biological diversity and provide clean water, Most jurisdictions also permit recreation in reserve areas. In some countries, tourism may contribute to the establishment and maintenance of reserves. The use of reserves for individual and commercial tourism and recreation is increasing very rapidly worldwide. The ecological impacts of this use, and the resources required to manage those impacts, are increasing correspondingly. Quantitative monitoring data on the types, extent and degree of such impacts, in relation to the types, timing and intensity of tourist activities, are hence vital, in order to manage reserves for their primary conservation purpose. Most importantly, reserve managers need early-warning indicators of tour­ist impacts, before those impacts reach the threshold of irreversible damage. Different types of impact have different relative significance in different ecosystems. Trampling by hikers does less lasting damage to vegetation in mesic than extreme environments, but weed seeds and fungal spores are more likely to establish. Human voices are a major disturbance to fauna in subtropical rain­forest, but not on snowcapped mountaintops. Human wastes can cause a far greater increase in nutrient concentrations in small alpine ponds or desert waterholes than in higher-volume rivers. Hence different ecological parameters are more critical indicators of tourist impacts in different conservation reserves. Here, therefore, we describe an iterative approach to identifying a low threshold early-warning indicator of human recreational impacts for one such reserve. Specifically, the aim of this project was to test the effectiveness of microbiological water quality parameters as an early-warning indicator of the environmental impacts of tourism and recreation in a subtropical rainforest national park.