Post-industrial ecosystems (PIEs) occur on abandoned industrial sites; old-fields occur on abandoned agricultural lands. While old-fields have been extensively studied, PIEs have not and provide an interesting comparison with old-fields. Old-fields in temperate climates generally follow a successional pathway of early dominance by annuals and biennals followed by perennial herbaceous plants, then shrubs and young trees, and develop into a persistent forest ecosystem in the absence of disturbance. The rate of old-field succession, measured by woody plant establishment, has been found to vary in response to temperature, soil fertility and plant traits. Pathways and rates of succession in PIEs are unknown and may differ from those in old-fields due to the differences in agricultural and industrial disturbance, and due to the extreme soil conditions or traits of a potentially unique plant community in PIEs. We compared the successional pathways and rates of succession in old-fields and PIEs. We based our comparison on published literature for both ecosystems and using field-data collected at twenty PIEs in western New York, USA. Field-data and methods included tree basal area from point-center quarter sampling, understory tree and shrub cover along line-intercept transects, and ground vegetation cover in 1-m2 quadrats.
Results/Conclusions
Based on the tree basal area at the twenty PIE field-sites, there was not a single pathway such as found in old-fields. Instead, some PIEs progressed toward a woodland while others remained as open communities decades after industrial abandonment. There was little regeneration of the existing tree canopy species or presence of other tree species in the ground vegetation indicating a woodland community will not persist beyond the lifespan of the existing tree canopy. Correlations of species abundance with NMDS scores based on species importance values suggest that the vegetation structure in PIEs is strongly related to the abundance of the native tree Populus deltoides and the non-native shrubs Rhamnus cathartica and Lonicera species, all of which are capable of long-distance dispersal. The time to 10% woody plant cover in PIEs was initially faster than in old-fields and then slower to reach 50% cover, but not significantly different in t-tests. This may reflect the early dominance of fast growing trees and non-native shrubs, followed by little tree regeneration or colonization by other tree species. From these results, we cannot expect PIEs to follow similar pathways as old-fields and successional rates may also differ.