Formal quantitative surveys of wild animal abundance or activity, and assessments of the integrity of the complex natural ecosystems they live in, are typically quite laborious and meaningful analysis of the data obtained may require considerable time and expertise. This study describes the development and evaluation of a practical procedure for semi-quantitative synthesis of consensus subjective impressions accumulated by a small team of investigators who visited 32 different locations distributed in or around a community-based Wildlife Management Area in southern Tanzania. The subjective natural ecosystem integrity index scores obtained represent a holistic indicator of all aspects of land use, wildlife and human activities, which correlated strongly with objective indicators of wild animal community or whole natural ecosystem integrity that were estimated directly from formally collected quantitative survey data by the same investigators at the same locations. Also, comparative regression analysis indicated that the SNEII was a far more sensitive to variations in observed human activities than any of the objective alternatives, correspondingly yielding far more detailed insights into ongoing conservation challenges. This simple procedure for summarizing the overall, multi-faceted subjective impressions of individuals traversing extensive conservation areas may well be applicable through participatory approaches to routine programmatic monitoring by community-based staff with minimal training, and may therefore be more practically useful to devolved conservation areas like WMAs than conventional objective statistical synthetic indices relying on laborious collection and analysis of quantitative survey data.