| Indicators of general ecosystem functioning are important in understanding and managing natural resources. A synthesis of factors affecting the state of an ecosystem is vegetation, where composition and productivity, and their extent and spatial pattern, reflect a combination of geo-climatic, ecological, and anthropogenic factors, as well as ecological function such as succession and competition. Net primary production (NPP), predicted at medium resolution (8km) over large areas and many years, is a potential measure of the magnitude of vegetation productivity.; To generate landscape NPP across Ontario, a methodology is developed using the relationship between the amount of incident photosynthetically active solar radiation (PAR), the fraction that is absorbed (derived from the remotely sensed Normalized Difference Vegetation Index (NDVI)), and the light use efficiency (LUE) of the ecosystem at utilising this energy. Landscape-level predictions of LUE are calculated using a relationship between long-term climate normals, which characterise the spatial variability between ecosystems, and monthly climate data, which capture the seasonal variability within an ecosystem. Photosynthetically active radiation is generated across Ontario, and it is shown that the commonly used Geostationary Operational Environmental Satellite dataset over-predicts solar radiation across the province.; This methodology is used to generate sixteen years (1981 to 1996) of monthly NPP, which are explored for trends using aggregation ecounits from the National Ecological Framework of Canada ecoregionalization. Across Ontario these results show increases in both seasonal and annual NDVI and NPP, although increases in NPP are not distributed evenly across the growing season. These results support other reported evidence for changing climatic conditions. Summary statistics of both NDVI and NPP characterise differences between ecounits. NDVI is used to develop spatio-temporal signatures, which summarise the seasonal structure of climate and NDVI within each ecounit. The suitability of the ecoregionalization for exploring NPP is also assessed, by examining both the internal homogeneity of ecounits and the strength of the ecounit boundaries.; Bridging the gap between local and global studies, this research provides a useful methodology to generate a multi-year series of 8km NPP, and analysis techniques for the spatio-temporal exploration of this series using an ecoregionalization. |
