Atmospheric Nitrogen (N) has been recognized as one of the main influential drivers of biodiversity loss on a global level. In this context it is important to understand to what extent N deposition is impacting Canadian forest habitats and ecosystems. The objective of this study is to assess the impact of N deposition to forest understorey taxa distribution changes and identify change thresholds across N deposition gradients in Canadian forest ecosystems. A method called Threshold Indicator Taxa Analysis (TITAN) was applied to assess taxa that significantly change in abundance along N deposition gradients, identifying the points along each gradient at which the most significant individual changes occurred. Indicator species scores were used to integrate occurrence, abundance and directionality of taxa responses. Community-level thresholds were determined based on the convergence of individual taxa abundance change points, using selected data from Saskatchewan's Provincial Forest Ecosites and presented by forest habitat. Identifying these thresholds will assist to assess N critical loads for each of the habitats, which in turn can be helpful in establishing emissions reduction policies.