What can history tell us about our ability to influence the condition of natural resources?
1. What can history tell us about our ability to
influence the condition of natural resources?
Ted Lefroy
2. What can history tell us about our
ability to influence the condition
of natural resources?
Ted Lefroy
University of Tasmania
3. Water quality in Tasmanian rivers and estuaries
Oral history, sediment
Water quality data
cores
Response to intervention
Large infrequent events
1. Sediment cores
2. Space-for-time exp.
**
3. Air photo analysis
Historic WQ data,
space for time exp.
Disturbance thresholds for 4. WQ/veg condition data
Tasmanian rivers *
5. Historical records
6. Oral history
Sediment cores, air photos, historical records
Biotic cycles and Large infrequent events
7. Duck River
Oral history, air photos, sediment dating
Black River, Detention River
Cobble bottom
Sediment dating
Oral history
Mud banks
Duck River, Montagu River
12. The Pet River
16 km2 catchment
5-25% of sub-catchments treated
12 sub-catchments monitored for 7 years
No detectable change in N or P
13. Vegetation change 1946-2006
1946
2006
% Canopy cover
?
Large Infrequent Events: Gold, Fire
Slow drivers: rabbits, sheep, Landcare, wool prices, tree change
1800 1870 1940 2010
Regeneration = 2 x Revegetation Private investment ~ 2 x Public
14. Summary 1
1. Multiple lines of evidence
– Sediment cores
– Space-for-time experiments
– Air photo analysis
– Historic WQ/veg condition data
– Oral history
– Historical records
15. Summary 2
2. In combination, they can be used to identify
– Biotic cycles
– Large infrequent events
– Human disturbance
– Recovery in vegetation extent
3. ….but its more challenging to
– Document recovery in water quality
– Document change in vegetation condition
16. Acknowledgements
Estuarine research – John Gibson, Barry Gallagher, Jeff Ross and Christine Crawford
Fresh water – Nelli Horrigan, Reg Majierowski, Steve Read and Peter Davies
Riparian – Shane Broad, Bill Cotching and Ross Corkery
Vegetation change – Garreth Kyle, Dave Duncan, Libby Rumpf and Graeme Newell
www.landscapelogic.org.au