Degradation of the Albany Thicket Biome. How much of the extent remains 20 years after the initial mapping in 1998?

Abstract

The Albany Thicket Biome is highly resistant to a wide variety of disturbances but, once disturbed, lacks the regenerative qualities that allow it to return to its original stable state. This study investigated the degradation status and the remaining extent of intact thicket. Classification of each thicket type was determined using Maximum Likelihood Classification and patch analysis using Fragstats. Of the four major divisions of the Albany Thicket Biome, classification of the Mesic, Valley and Dune Thickets were successful. The classification indicated that almost half of these thicket types has been lost, transformed or degraded by agricultural or urban development. For Dune, Mesic and Valley Thicket, thicket fragment sizes ranged between 6 and 876 km2. Dune Thicket contained the smallest fragments (2 km2) of intact thicket, while Valley Thicket contained the largest fragments (251 km2) of intact thicket of the major divisions of the Albany Thicket Biome. The misclassification of Arid Thicket precluded an accurate determination of the level of degradation and a different approach to assess the degradation status will have to be devised for these open thicket areas that contribute 39% of the original extent of the biome.