Freshwater ecosystem services provided by New Zealand s planted forests. B. R. Baillie

Transcription

1 Freshwater ecosystem services provided by New Zealand s planted forests B. R. Baillie

2 Presentation Outline Water quality in New Zealand s planted forests Land use comparison Freshwater ecosystem services Implications/challenges of the NZ freshwater policy

3 Water quality in New Zealand s planted forests Key findings: Rapid changes from afforestation (pasture to pine) within 5-6 years Mid-rotation to mature forest, WQ generally high Baillie B.R.; Neary, D.G. Water quality in New Zealand s planted forests: A review. (DRAFT) & references therein

4 Water quality in New Zealand s planted forests Harvesting can have a large impact on water quality Mitigated by riparian areas, logging slash over channel, underlying hydrology, flatter topography Recovery time is highly variable

5 Estimated suspended sediment yields in a Hawke s Bay planted forest catchment. Based on data from Fahey & Marden (2006)

6 Land use comparison Water quality & biota similar to native forest or intermediate between native and pasture Exceptions turbidity, P in lakes, fish

7 Estimated suspended sediment yields from a planted forest & pasture catchment in the Hawke s Bay region Based on data from Fahey & Marden (2006)

8 Larned et al. (2004). Water quality in low-elevation streams and rivers of New Zealand: recent state and trends in contrasting land-cover classes.

9 Biological Factors e.g. organic matter, faunal diversity Pastoral Scrubland Pine Beech Forest Forest Deleatidium spp. C. humeralis S. prasina O. feredayi Deleatidium spp. A. cyrene S. prasina Deleatidium spp. P. antipodarum Eukiefferiella sp. O. albiceps Adapted from Harding & Winterbourn (1995). Beech Pine Scrubland Pastoral Forest Forest Abiotic Factors e.g. degree of modification, water temperature

10 Functions & processes underpinning freshwater ecosystem services from planted forests Evapotranspiration Precipitation Interception Tree uptake Wood & litter input Shade Recharge Groundwater flow Quality of water Quantity & timing of flow Aquatic biodiversity/fisheries

11 Function/process/attribute Filtration/storage/ movement Removal sediment/nutrient/ microbes Shade Organic inputs Flow reduction Timing of flow Flow pathways Thermoregulation Light regime Large woody debris Litter Flow regime Flood mitigation Water quantity Ground water Water quality Aquatic ecosystem function habitat Ecosystem service Protection to downstream infrastructure & habitats Water supply (domestic, agricultural, & industrial) Aquaculture Food supply Community structure Biodiversity Rare species Recreation Aesthetics Knowledge/education Scientific research Cultural

12 Harvest (to the stream edge) effects on freshwater ecosystem services Removal of forest cover Disruption to evapotranspiration/infiltration processes Increased overland flow Reduced flood mitigation Lost the riparian vegetation Shade Terrestrial inputs Channel bank stability Decline water quality, biodiversity, ecosystem resilience Impact on freshwater resources Warmer water temperatures Increase sediment & nutrients Algae Change in aquatic community structure Increase water quantity

13 Implications/challenges of NZ s freshwater policy Cyclic nature of planted forests Setting of regional & national limits Exceptions - sediment Community/collaborative process Forest intensification

14 Freshwater management unit A A state harvest Water quality capacity B state