Parks and protected areas that provide recreational opportunities for visitors are often faced with a set of unique management challenges. Primarily, this includes balancing the preservation of the ecosystem with recreational use, often involving the mitigation of visitor behaviors. As well, various groups that may interact with these areas often have conflicting priorities for or opinions on management actions. In order to promote sustainable visitor behaviors, increase support for management initiatives, and address some of these conflicting opinions, an understanding of how environmental conditions are perceived among user groups is needed. Therefore, this study sought to illuminate how two groups that differ in their levels of experience and knowledge with respect to a protected area with high levels of visitation perceive the state of its environment. A survey was administered to people identified as “experts” on the Niagara Glen Nature Reserve (Ontario, Canada) as well as to those identified as more casual “visitors” to the reserve. Perceptions of ecological conditions are compared to empirical measurements. For both visitors and experts, the overall perceptions of environmental conditions differed significantly from the ecological data, with visitors generally providing higher ratings of ecosystem conditions, whereas experts generally provided lower ones. Visitors and experts also differed significantly from one another in their perceptions—a meaningful finding for understanding intergroup conflicts as well as the basis for support for management initiatives. The findings highlight the importance of considering perceptions of environmental conditions between groups, and of understanding how perceptions relate to measured ecological data.