Bad news for tasmanian alpine flora
Posted: Sun 27 Apr, 2014 8:13 pmBad news for tasmanian alpine flora:
The legacy of mid-Holocene fire on a Tasmanian montane landscape DOI: 10.1111/jbi.12229 Journal of Biogeography
This journal article looks at the sediment record of Lake Osborne in the Hartz Mountains National Park over the past 6500 years.
They found three significant periods of increased bushfires between 2900–2600 cal. yr bp (calendar years before present);( 5856, 4632 and 2966 cal. yr bp). The first fire resulted in the extinction of Nothofagus Gunnii.
N. cunninghamii and Eucryphia both took around 300 years to regenerate and a Cupressaceae (probably Athrotaxis) took 800 years to regenerate.
Later, two significant fire periods in succession (2900–2600 cal. yr bp) permanently shifted the vegetation to Eucalyptus-dominated vegetation.
This shift resulted in a decimation of the fertility of the basin and significantly decreased water retention.
Strangely enough all fire periods coincided with periods of very-high-frequency El Niño conditions, possibly showing a link between Tasmanian wildfires and El Niño conditions. Unfortunately "some climate model projections suggest that the ENSO system is vulnerable to crossing a tipping point due to anthropogenic climate change, with a projected increase in the frequency and intensity of El Niño events in the future"
Alpine fires are a rare event, even with Aboriginal use of fires. It "is certain is that Aboriginal fire usage did not limit the re-expansion of forests in many settings at the end of the Pleistocene." This changed with European colonization.
TL;DR.
One significant fire event is enough to eradicate N. Gunni
N. cunninghamii and Eucryphia take around 300 years to regenerate.
Increased El Niño activity probably decreases extent of these species.
The legacy of mid-Holocene fire on a Tasmanian montane landscape DOI: 10.1111/jbi.12229 Journal of Biogeography
This journal article looks at the sediment record of Lake Osborne in the Hartz Mountains National Park over the past 6500 years.
They found three significant periods of increased bushfires between 2900–2600 cal. yr bp (calendar years before present);( 5856, 4632 and 2966 cal. yr bp). The first fire resulted in the extinction of Nothofagus Gunnii.
N. cunninghamii and Eucryphia both took around 300 years to regenerate and a Cupressaceae (probably Athrotaxis) took 800 years to regenerate.
Later, two significant fire periods in succession (2900–2600 cal. yr bp) permanently shifted the vegetation to Eucalyptus-dominated vegetation.
This shift resulted in a decimation of the fertility of the basin and significantly decreased water retention.
Strangely enough all fire periods coincided with periods of very-high-frequency El Niño conditions, possibly showing a link between Tasmanian wildfires and El Niño conditions. Unfortunately "some climate model projections suggest that the ENSO system is vulnerable to crossing a tipping point due to anthropogenic climate change, with a projected increase in the frequency and intensity of El Niño events in the future"
Alpine fires are a rare event, even with Aboriginal use of fires. It "is certain is that Aboriginal fire usage did not limit the re-expansion of forests in many settings at the end of the Pleistocene." This changed with European colonization.
TL;DR.
One significant fire event is enough to eradicate N. Gunni
N. cunninghamii and Eucryphia take around 300 years to regenerate.
Increased El Niño activity probably decreases extent of these species.