Landscape and Productivity Changes in Southeastern Michigan, USA

Changes in landscape composition and productivity between 1991 and 1999 were examined over Southeastern Michigan. The pixel-wise changes were first summarized by 2000 Census block groups, which were grouped by settlement density. According to the areaweighted average, built-up area increased by 8.85%, forest increased by 13.73%, and agriculture decreased by 22.38%. During the same time period, annual gross primary production (GPP) increased 60 g C m on average over the region. We then analyzed patterns within the region by development pattern class (urban, suburban, exurban, and rural) and by county development speed (rapid, intermediate, and slow or declining). The increment of annual GPP was highest in exurban/rural areas settled at low-densities, due to expanding forest cover (converted from agriculture). In contrast, increases were lowest in densely settled urban/suburban areas and in rapidly developing counties, due to the large expansion of built-up areas (also converted from agriculture). Our study showed that changes in GPP were heterogeneous and that low-density development was accompanied by relatively large increases in GPP. The methods of using AVHRR together with publicly available Census data facilitate extending the research to state and national scales.