ABSTRACT

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Methods and Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

The Herbert River Catchment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Landcover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Surface Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Contemporary Broadscale Landcover Change in GBRMP Catchments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Landcover Change in the Herbert River Catchment . . . . . . . . . . . . . . . . . . . . 26 Water Quality in the Herbert River Catchment . . . . . . . . . . . . . . . . . . . . . . . . 27

Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

The Great Barrier Reef Marine Park (GBRMP) covers an area of approximately 350,000 km2 and spans almost 2,000 km of the east coast of Queensland, Australia. The GBRMP is a marine ecosystem that is recognised internationally for its unique biological and physical features. Fifteen river catchments, covering an area of approximately 375,000 km2, drain directly into the GBRMP (Figure 1). Land use in these catchments is dominated in areal terms by grazing. Cropping, particularly sugarcane production, is a major user of land resources in a number of catchments and is predominantly located on fertile coastal floodplains immediately adjacent to GBRMP waters (Table 1).