Wednesday, May 28, 2008 - 11:00 AM
409

Determining the relative influence of landuse and water source on cave and spring ecosystems

Aslan E. Wright-Stow, Mike Scarsbrook, and Kristel van Houte-Howes. NIWA, PO Box 11-115, Hamilton, New Zealand

Caves and springs in karst landscapes are highly valued for their association with indigenous culture, biodiversity values, recreation and tourism, and water supply. However, these values are threatened by human activities including pastoral farming. Extensive surveys of cave and spring habitats in karst areas of New Zealand’s central North Island were undertaken to compare water quality and invertebrate communities in cave systems draining pasture and native forest. During our surveys we also identified three karst habitat types, each with distinct hydrogeological properties: i) cave streamways, dominated by water sourced from submerged runoff-dominated streams; ii) side passages, which often had no identifiable surface stream component and were groundwater-dominated; and iii) springs or resurgences, which varied in water source. Invertebrate community structure was strongly influenced by water source and habitat type, but only weakly associated with differences in landuse. Cave streamways and springs with surface-dominated hydrology tended to have communities similar to those of surface streams, whereas groundwater-dominated side passages had a more taxonomically distinct fauna, including stygobitic amphipods. Landuse did have significant effects on nitrate concentrations, but temperature and conductivity responded more strongly to hydrogeology. We suggest that karst aquatic habitats may be buffered against some negative impacts of intensive landuse.


Web Page: Caves, springs, landuse

See more of Land/Water Interfaces II
See more of Contributed Sessions

See more of The Nabs 56th Annual Meeting (25-28 May, 2008)