COS 2-1 - Hydrological influences of forest landscape pattern: a review

Abstract: There is a growing interest in forest landscape patterns and their effects on hydrological processes. However, there is no review to summarize the findings. The objectives of this study were to synthesize the influences of forest landscape pattern on water quality and water yield, using both a meta-analysis and a qualitative literature review. The meta-analysis on water quality revealed that forest largest patch index (LPI) and aggregation index (AI) were significantly and negatively correlated with streamflow nitrogen concentrations, whilst forest landscape shape index (LSI) and patch density (PD) exhibited a significantly positive correlation with streamflow nitrogen concentrations. These results suggest that forest fragmentation can have negative impacts on water quality especially by increasing terrestrial nitrogen leaking to streams, which is likely due to intensified forest edge effects on atmospheric deposition in fragmented forests. The literature review on water yield indicated that forest landscape pattern affects water infiltration, accumulation, and movement in the process of runoff generation, leading to variations in the residency time of water in a watershed. The relative locations of forests to runoff sources play a remarkable role in determining the timing of peak flow. Overall, this study highlights the importance of considering forest landscape patterns in the design of forest management strategies for protection of water quality and hydrological functions.