Mark Lethbridge: 'What have we learnt about feral camel movements, population dynamics and...
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Transcript of Mark Lethbridge: 'What have we learnt about feral camel movements, population dynamics and...
Reducing feral camel impacts across remote Australia:
Australian Feral Camel Management Project
21st November 2013, Parliament House Theatre, Canberra
Session Three: Achievements and Outcomes Speakers: Mark Lethbridge, Ecoknowledge Jayne Brim Box, Northern Territory Government Sam Rando, Central Land Council Karl Hampton, Ninti One Lyndee Severin, Curtin Springs Station Jan Ferguson, Ninti One
Dr Mark Lethbridge
What have we learnt about feral camel movements, population dynamics and management
Camel monitoring and removal planning
• Satellite Tracking Habitat utilisation – removal planning Finding animals – Judas collars
• Aerial surveys
Monitor changes in the population Distribution – removal planning
• Decision Support Tools
Removal cost estimation Finding animals – Judas collars
Satellite Tracking
Dunes
2007 Aerial Survey
and 2007-09 Tracking
data
+
• From conference
Bulloo
DeGrey
Channel
Mandora
Rudall
Serpentine
Goyder
Dalhousie
George Hill Hay River
Uluru
West MacDonnell
Petermanns
West Finke
Algebuckina
Glen Helen
Eyre
Mound springs
Aerial Surveys
400 metres - added for low densities
200m strip
8%
10%
12%
14%
16%
18%
20%
22%
24%
26%
28%
30%
32%
0 0.1 0.2 0.3 0.4 0.5 0.6
Estim
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Pre
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Esimated density of camels
200 metre strips 600 metres strips
0
10
20
30
40
50
60
70
80
90
100
0.4
0.7
0.9
1.2
1.4
1.7
1.9
2.2
2.4
2.7 3
3.2
3.5
3.7 4
4.2
4.5
4.7 5
5.2
5.5
5.7 6
6.2
6.5
6.7 7
7.2
7.5
7.8 8
8.3
Perc
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/- e
rror
of a
bund
ance
est
imat
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Sample effort % (transect width dependent)
Simpson culled mobs (av=15.1)
GVD recorded mobs (av= 4.7)
Ξ 200 m
Now
2008
Buffer Density Abundance Density Abundance 0-50km Serpine Lakes 0.21 4172 0.40 7779 0-50km Algebuckina Waterhouse, Lake Eyre, Lake Eyre Mount Springs 0.03 0.22 0-50km Goydor Lagoon 0.04 744 0.21 4251 0-50km Dalhousie Spring 0.10 1043 0.24 2596 0-50km Hay River & channel Country 0.04 3136 0.26 18518
0-50km Western MacDonnell Ranges, Glen Helen Mound Springs, Uluru Kata Tjuta, Petermann Ranges 0.22 24748 0.74 82423
0-50km Rundall River National Park 0.03 1439 0.27 12239 0-50km DeGrey River 0.00 0.02 0-50km Mandora Salt Marsh 0.00 0.04
50-100km Bulloo River and Lake 0.00 0.00 50-100km Serpine Lakes 0.22 6669 0.36 11074
50-100km Goydor Lagoon, Algebuckina Waterhouse, Lake Eyre, Lake Eyre Mount Springs, Dalhousie Spring, Hay River & channel Country 0.05 0.28
50-100km Western MacDonnell Ranges, Glen Helen Mound Springs, Uluru Kata Tjuta, Petermann Ranges 0.30 25959 0.74 64581
50-100km Rundall River National Park 0.03 1418 0.11 5121 50-100km DeGrey River 0.00 0.03 50-100km Mandora Salt Marsh 0.01 0.04
Target assets
Aerial Survey and Kriging interpolation/extrapolation
• Population in 2008 208,582 • Population in 2013 69,328
139,254 • Known Removals ~123,000 or 58.9% loss Unaccounted for ~16,000
In target asset areas + 100kms
• Aerial surveys targeted changes in density in and around assets – good agreement with removal data
• Much greater uncertainty of camel densities well away from survey
areas. – project focus was on removals, thus limited aerial survey coverage
• The 2008 map used older survey data back to 2001, corrected for a 9%
per annum increase in population growth rate. – Assumed no movement and constant growth rate – the latter now unlikely
• Accordingly, the 2013 map only uses 2013 data – thus conservative
• Analysis methodologies have improved.
Uncertainty away from asset areas
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2008
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2013
Other findings
• Large losses of camels in the Simpson Desert and poor condition animals seen further to the west
- Very low rainfall period after good season and fire • Population modelling now suggests rainfall has an influence and the average
population growth rate may be as low as 5% - A research question but currently no funding to support this work
Kriging estimate
2008 Improved estimate 600,000
2013 Now more likely 300,000 – 400,000 Unlikely there has been a net population growth over the period of the project with more recent fire and drought conditions. 600,000 – 160,000 known removals = 440,000 - so 40,000 – 130,000 unaccounted for.
SA – Simpson Desert May 2010
SA – Simpson Desert October 2010
NT – Simpson Desert Sept 2012
NT – Western Desert March 2012
NT – Western Desert July 2012
WA – Ngaanyatjarra/Kiwirrkurra October 2011
WA – Ngaanyatjarra/Kiwirrkurra March 2012
Decision Support Systems
0
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Freq
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y as
a P
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ntag
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Sighted Distance from Aircraft (m)
WA SA NT
Broader Decision Tool
Estimate site-specific removal costs
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