Regional economic development and the development of transportation networks are known to be strongly correlated. For landscape ecologists, road networks are indicators of human use. There are numerous ecological effects of roads, which are exacerbated as road networks develop. Studies describing the relationships between regional economies and road networks, and roads and landscapes largely ignore local roads in the analysis because accurate maps of dynamic local road systems are difficult to obtain. However, local logging and agricultural roads are principal ways used to access remote areas in pursuit of recreational or resource extraction activities. They also provide mechanized access to undeveloped areas, facilitating land cover change. Previous work in Florida showed that the addition of dead-end roads was one of the most important changes to the rural road network in the later 20th century. This analysis extends that study to characterize changes in a similar, rural road network in the Colorado Front Range, as it changed from 1937 to 2007. What similarities and differences exist between road networks in Colorado and Florida? How did changes in the road network relate to changes in land cover? Road network structures in Colorado and Florida were characterized as they changed over time, and the results compared. Land cover change at specific points in the road network was compared with a random selection of points in the landscape to evaluate if road network location was related to type of land cover change.
Results/Conclusions
The development of the road network in Colorado exhibited structural similarities to that of Florida. In both places, from 1975 to 2005, the extent of the road networks increased by over 20%. As extent increased, the connectivity of the road networks declined and the proportion of dead-end roads increased. In Florida, land cover in the study area changed disproportionately from less intensive land uses to more intensive land uses (e.g. forest to urban), but the effect was more pronounced at dead-end road termini. From 1988 to 2004, more than 23% of the points adjacent to dead end road termini built between 1975 and 1985 converted to urban land cover. This proportion was significantly greater than the proportion of urbanizing points located either adjacent to through roads (15%) or in the broader landscape (12%). These results provide strong evidence for an urbanizing effect of dead-end roads in this region of Florida. Similar land-cover change analyses are underway for the Colorado road networks.
