Is a picture worth a thousand species? Evaluating human perception of biodiversity intactness using images of cumulative effects

Public demand to conserve biodiversity has resulted in increased monitoring efforts for a vast number of species. Faced with reporting on the large amounts of information generated by biodiversity monitoring, there is a desire to have state variables that simplify this complexity. Intactness indices describe the deviation of the state of biodiversity from a specified reference condition. An effective intactness index should not only statistically describe changes in biodiversity when change occurs but also resonate with people in a way that they have a clear picture of the type of change that has occurred. We used an online survey to evaluate whether public perception of cumulative impacts as viewed through images of disturbed boreal landscapes was correlated with actual indices of avian biodiversity intactness. We found people accurately ranked landscapes with the most human disturbance relative to an undisturbed reference state. The variable the best predicted perceived intactness was the proportion of mature forest cover remaining. Dissection by roads and fragmentation effects by forestry, agriculture, and urbanization explained less but a significant amount of variation. Biocentric individuals and non-hunters viewed landscapes as generally being less intact. Absolute intactness scores from field data deviated from perceived intactness. Landscapes with little human disturbance (i.e. a single road) were perceived to have lower intactness than what was actually observed in bird communities and landscapes with no forest were perceived as being more impacted than they were. Intactness indices can enhance understanding of biodiversity change but caution must be exercised to ensure a clear understanding of what the absolute value of indices represent. (C) 2012 Elsevier Ltd. All rights reserved.