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Dunnart Model

Title:	Dunnart Model
Date Created:	12/12/2009
Short Description:	Habitat suitability model for the Julia Creek Dunnart
Long Description:	None
Version:	1
Authors:	Carl Smith, Alison Howes, Bronwyn Price, Clive McAlpine
Categories:	DBL Interactive Training Materials, Examples
Target Audiences:	Everyone
Total Nodes:	12
Total Nature Nodes:	12
Total Decision Nodes:	0
Total Utility Nodes:	0

Nodes

Ten_mapped

Type:	Nature
Discrete / Continuous:	Discrete
Short Name:	Ten_mapped
Long Name:	Mapped Land Tenure
Short Description:	None
Long Description:	The tenure of the land under investigation.
Parents:	None
Children:	Water_dist_km, Ten, PA_den_mapped
Total States:	3
Hidden:
Enabled:
Default State:	None
Display Colour:	Lime

States

Short Title	Long Title	Real Value	State Value	Sort Order	Description
Reserve				1
Stock_Route				2
Grazing				3

Probabilities

Reserve	Stock_Route	Grazing
0.023	0.051	0.926

Water_dist_km

Type:	Nature
Discrete / Continuous:	Discrete
Short Name:	Water_dist_km
Long Name:	Distanceto Water km
Short Description:	None
Long Description:	The distance cattle travel from water can have a significant impact on the grazing pressure within the region. Grazing and erosion is likely to be heavier around watering points, decreasing the abundance of ground cover species. This movement of cattle to and from watering points may also encourage the spread of weeds such as Prickly acacia. This spread will only occur in regions already containing the seed source. Cattle can travel up to 5km from watering points. States: 0-5km travel distance to water &gt;5km travel distance to water
Parents:	Ten_mapped
Children:	PA_den_mapped, Grazing
Total States:	2
Hidden:
Enabled:
Default State:	None
Display Colour:	Aqua

States

Short Title	Long Title	Real Value	State Value	Sort Order	Description
Greater_Than_5				1
Zero_to_Five				2

Probabilities

Ten_mapped	Greater_Than_5	Zero_to_Five
Reserve	0.6046718	0.3953282
Stock_Route	0.7387773	0.2612226
Grazing	0.7151339	0.2848661

Ten

Type:	Nature
Discrete / Continuous:	Discrete
Short Name:	Ten
Long Name:	Land Tenure
Short Description:	None
Long Description:	The tenure of the land under investigation.
Parents:	Ten_mapped
Children:	Grazing
Total States:	3
Hidden:
Enabled:
Default State:	None
Display Colour:	Aqua

States

Short Title	Long Title	Real Value	State Value	Sort Order	Description
Reserve				1
Stock_Route				2
Grazing				3

Probabilities

Ten_mapped	Reserve	Stock_Route	Grazing
Reserve	1	0	0
Stock_Route	0	1	0
Grazing	0	0	1

PA_den_mapped

Type:	Nature
Discrete / Continuous:	Discrete
Short Name:	PA_den_mapped
Long Name:	Mapped Prickly Acacia Density plants/ha
Short Description:	None
Long Description:	Prickly acacia can only spread once there is a seed source within the region. The movement of cattle to and from watering points and along bore drains will encourage the spread. High rainfall will also encourage the spread of seed and increase the density of this weed. The roots of this weed withdraw moisture from the soils and prevent cracking occurring. Heavy infestation of this weed can reduce the abundance of native grasses dramatically. A canopy cover of 25-30% will reduce pasture production by 50% and pasture growth is prevented by 50% cover. Low: A density of less than 50 plants/ ha Medium: A density of 50-150 plants / ha High: A density of more than 150 plants/ ha
Parents:	Ten_mapped, Water_dist_km
Children:	PA_den
Total States:	3
Hidden:
Enabled:
Default State:	None
Display Colour:	Lime

States

Short Title	Long Title	Real Value	State Value	Sort Order	Description
Low				1
Medium				2
High				3

Probabilities

Ten_mapped	Water_dist_km	Low	Medium	High
Reserve	Greater_Than_5	0.5560345	0.1422414	0.3017241
Reserve	Zero_to_Five	0.5194805	0.1298701	0.3506494
Stock_Route	Greater_Than_5	0.6506124	0.1534503	0.1959373
Stock_Route	Zero_to_Five	0.5767367	0.1534733	0.26979
Grazing	Greater_Than_5	0.6549605	0.1716686	0.1733708
Grazing	Zero_to_Five	0.6087729	0.1797223	0.2115048

Season

Type:	Nature
Discrete / Continuous:	Discrete
Short Name:	Season
Long Name:	Rainfall
Short Description:	None
Long Description:	Heavy rainfalls of up to 600mm are usually received during the months of Jan, Feb to late March. The drier periods receive less than 400mm and extend from May to December. During this time, extensive cracks may form in the cracking clay soils. Heavy rains waterlog the soils and fill in the cracks that are produced during the dry seasons. Heavy rainfall encourages the spread of Prickly acacia infested regions. Summer rainfall improves pastures with the return of short lived annual forbs. The abundance of fauna species is likely to increase after periods of heavy rain, with the return of ground cover and suitable food sources. States: 0-400mm; usually between May to December 400-600 or greater; usually between Jan to March
Parents:	None
Children:	Grazing, Cover, Cracks
Total States:	2
Hidden:
Enabled:
Default State:	None
Display Colour:	Lime

States

Short Title	Long Title	Real Value	State Value	Sort Order	Description
Dry				1
Wet				2

Probabilities

Dry	Wet
0.5	0.5

Grazing

Type:	Nature
Discrete / Continuous:	Discrete
Short Name:	Grazing
Long Name:	Grazing Pressure % Utilisation
Short Description:	None
Long Description:	Mitchell grass pastures are grazed extensively by both sheep and cattle. Although the Mitchell grass species (Astrebla sp) can withstand a certain degree of grazing pressure, the percentage of ground cover left during grazing and its ability to regernate is an indication of the degree of grazing pressure. Ground cover should not be reduced below 30%, but often is in these regions. No more than 70% ground cover is usually found within these systems. The distance from water will also determine the grazing pressure within the regions, as areas closer to water sources are likely to be grazed more heavily. The average rainfall received with also affect the grazing pressure and the ability for ground cover to regenerate. Ground cover reduces during the drier season, however this is also dependant on the amount of rainfall received prior to this. Low: &gt;60% of ground cover remains Medium: 35-60% ground cover remains High: Less than 35% ground cover remains
Parents:	Water_dist_km, Season, Ten
Children:	Cover
Total States:	3
Hidden:
Enabled:
Default State:	None
Display Colour:	Yellow

States

Short Title	Long Title	Real Value	State Value	Sort Order	Description
Low				1
Medium				2
High				3

Probabilities

Water_dist_km	Season	Ten	Low	Medium	High
Greater_Than_5	Dry	Reserve	0.9	0.1	0
Greater_Than_5	Dry	Stock_Route	0	0.7	0.3
Greater_Than_5	Dry	Grazing	0	0.5	0.5
Greater_Than_5	Wet	Reserve	0.9	0.1	0
Greater_Than_5	Wet	Stock_Route	0.6	0.4	0
Greater_Than_5	Wet	Grazing	0.3	0.7	0
Zero_to_Five	Dry	Reserve	0.75	0.25	0
Zero_to_Five	Dry	Stock_Route	0	0.4	0.6
Zero_to_Five	Dry	Grazing	0	0.1	0.9
Zero_to_Five	Wet	Reserve	0.9	0.1	0
Zero_to_Five	Wet	Stock_Route	0.4	0.6	0
Zero_to_Five	Wet	Grazing	0.25	0.6	0.15

PA_den

Type:	Nature
Discrete / Continuous:	Discrete
Short Name:	PA_den
Long Name:	Prickly Acacia Density plants/ha
Short Description:	None
Long Description:	Prickly acacia can only spread once there is a seed source within the region. The movement of cattle to and from watering points and along bore drains will encourage the spread. High rainfall will also encourage the spread of seed and increase the density of this weed. The roots of this weed withdraw moisture from the soils and prevent cracking occurring. Heavy infestation of this weed can reduce the abundance of native grasses dramatically. A canopy cover of 25-30% will reduce pasture production by 50% and pasture growth is prevented by 50% cover. Low: A density of less than 50 plants/ ha Medium: A density of 50-150 plants / ha High: A density of more than 150 plants/ ha
Parents:	PA_den_mapped
Children:	Cover, Cracks
Total States:	3
Hidden:
Enabled:
Default State:	None
Display Colour:	Aqua

States

Short Title	Long Title	Real Value	State Value	Sort Order	Description
Low				1
Medium				2
High				3

Probabilities

PA_den_mapped	Low	Medium	High
Low	0.8490566	0.09433964	0.05660379
Medium	0.9354838	3.225806E-08	0.06451616
High	0.4285714	0.2857143	0.2857143

Cover

Type:	Nature
Discrete / Continuous:	Discrete
Short Name:	Cover
Long Name:	Ground Cover %
Short Description:	None
Long Description:	The level of grazing pressure has a direct affect on the level of ground cover remaining. This is also determined by the season and the type of soil. Astrebla species are capable of producing with just 40mm of rainfall. Rapid growth however follows the seasonal rainfall. Ground cover increases during the wetter months, with the return of annual forbs. As these dry out, and cattle continue to graze on these species, ground cover will decrease. It has been suggested however, that 20-50% forage use may also encourage the production of ground cover. The presence of Flinders grass species improves the percentage of ground cover during the dry season as it forms a matt as it dries. The presence of Prickly acacia is also of importance. This species competes with native grasses, producing patches of bare ground underneath this tree. Prickly acacia with a canopy cover of 25-30% will reduce pasture production by up to 50%. High: >60% ground cover Medium 35-60% ground cover Low: less than 35% ground cover
Parents:	Season, PA_den, Grazing
Children:	Suitability
Total States:	3
Hidden:
Enabled:
Default State:	None
Display Colour:	Yellow

States

Short Title	Long Title	Real Value	State Value	Sort Order	Description
High				1
Medium				2
Low				3

Probabilities

Season	PA_den	Grazing	High	Medium	Low
Dry	Low	Low	0.8	0.2	0
Dry	Low	Medium	0	0.7	0.3
Dry	Low	High	0	0	1
Dry	Medium	Low	0	0.5	0.5
Dry	Medium	Medium	0	0.25	0.75
Dry	Medium	High	0	0	1
Dry	High	Low	0	0	1
Dry	High	Medium	0	0	1
Dry	High	High	0	0	1
Wet	Low	Low	0.95	0.05	0
Wet	Low	Medium	0	0.8	0.2
Wet	Low	High	0	0	1
Wet	Medium	Low	0.3	0.7	0
Wet	Medium	Medium	0	0.9	0.1
Wet	Medium	High	0	0	1
Wet	High	Low	0	0.1	0.9
Wet	High	Medium	0	0.25	0.75
Wet	High	High	0	0	1

Dom_soil_mapped

Type:	Nature
Discrete / Continuous:	Discrete
Short Name:	Dom_soil_mapped
Long Name:	Mapped Dominant Soil Type
Short Description:	None
Long Description:	The soil type in the Mitchell grasslands consists of cretaceous sediments with deep grey and brown cracking clay soils, gravelly sandy soils, shallow brown clay soils with hard setting surfaces, and clays with stone cover. Deep brown and grey soils are capable of extensive cracking in dry seasons. The soil type also determines the abundance and type of ground cover species present in the region. Soils can be identified by colour, rock or pebble consistency, the dominance of sand, or gravel consistency. States: Clay soils; contain less than 40% gravel and rocks and over 60% clay texture that crack extensively in dry conditions. Sandy, gravel soils; contain less than 40% clay and over 60% sand or gravel texture that don't crack extensively in dry conditions.
Parents:	None
Children:	Dom_soil
Total States:	2
Hidden:
Enabled:
Default State:	None
Display Colour:	Lime

States

Short Title	Long Title	Real Value	State Value	Sort Order	Description
Clay				1
Sand				2

Probabilities

Clay	Sand
0.72	0.28

Dom_soil

Type:	Nature
Discrete / Continuous:	Discrete
Short Name:	Dom_soil
Long Name:	Dominant Soil Type
Short Description:	None
Long Description:	The soil type in the Mitchell grasslands consists of cretaceous sediments with deep grey and brown cracking clay soils, gravelly sandy soils, shallow brown clay soils with hard setting surfaces, and clays with stone cover. Deep brown and grey soils are capable of extensive cracking in dry seasons. The soil type also determines the abundance and type of ground cover species present in the region. Soils can be identified by colour, rock or pebble consistency, the dominance of sand, or gravel consistency. States: Clay soils; contain less than 40% gravel and rocks and over 60% clay texture that crack extensively in dry conditions. Sandy, gravel soils; contain less than 40% clay and over 60% sand or gravel texture that don't crack extensively in dry conditions.
Parents:	Dom_soil_mapped
Children:	Cracks, Suitability
Total States:	2
Hidden:
Enabled:
Default State:	None
Display Colour:	Aqua

States

Short Title	Long Title	Real Value	State Value	Sort Order	Description
Clay				1
Sand				2

Probabilities

Dom_soil_mapped	Clay	Sand
Clay	0.954023	0.04597702
Sand	3.333331E-07	0.9999996

Cracks

Type:	Nature
Discrete / Continuous:	Discrete
Short Name:	Cracks
Long Name:	Soil Cracks no./sq m
Short Description:	None
Long Description:	Cracks form in the soils during periods of limited rainfall. Deep clay soils crack more extensively than soils with a higher stone content. The roots of Prickly acacia infestation however prevent extensive cracking as they hold the soils together. The presence of cracks within the soils creates runways and hiding points for the Dunnart, from extreme heat and predation. The extensiveness of crack formation can be measured by the density of cracks/ sq meter. States: 0-1 cracks/ sq m 1-2 cracks/ sq m 2-3 cracks/ sq m
Parents:	Season, Dom_soil, PA_den
Children:	Suitability
Total States:	3
Hidden:
Enabled:
Default State:	None
Display Colour:	Yellow

States

Short Title	Long Title	Real Value	State Value	Sort Order	Description
gr_2				1
gr_1				2
less_1				3

Probabilities

Season	Dom_soil	PA_den	gr_2	gr_1	less_1
Dry	Clay	Low	0.9	0.1	0
Dry	Clay	Medium	0.5	0.5	0
Dry	Clay	High	0	0	1
Dry	Sand	Low	0	0	1
Dry	Sand	Medium	0	0	1
Dry	Sand	High	0	0	1
Wet	Clay	Low	0	0	1
Wet	Clay	Medium	0	0	1
Wet	Clay	High	0	0	1
Wet	Sand	Low	0	0	1
Wet	Sand	Medium	0	0	1
Wet	Sand	High	0	0	1

Suitability

Type:	Nature
Discrete / Continuous:	Discrete
Short Name:	Suitability
Long Name:	Suitability
Short Description:	None
Long Description:	Studies have indicated that the most suitable form of habitat for the Julia Creek Dunnart includes extensive cracking soils and adequate ground cover to escape both predation and the hot temperatures. The better the habitat description the greater the probability of dunnart occurrence.
Parents:	Cover, Cracks, Dom_soil
Children:	None
Total States:	3
Hidden:
Enabled:
Default State:	None
Display Colour:	Red

States

Short Title	Long Title	Real Value	State Value	Sort Order	Description
High				1
Medium				2
Low				3

Probabilities

Cover	Cracks	Dom_soil	High	Medium	Low
High	gr_2	Clay	0.6	0.4	0
High	gr_2	Sand	0	0	1
High	gr_1	Clay	0.4	0.6	0
High	gr_1	Sand	0	0	1
High	less_1	Clay	0.4	0.6	0
High	less_1	Sand	0	0	1
Medium	gr_2	Clay	0	0.5	0.5
Medium	gr_2	Sand	0	0	1
Medium	gr_1	Clay	0	0.3	0.7
Medium	gr_1	Sand	0	0	1
Medium	less_1	Clay	0	0.2	0.8
Medium	less_1	Sand	0	0	1
Low	gr_2	Clay	0	0.2	0.8
Low	gr_2	Sand	0	0	1
Low	gr_1	Clay	0	0.1	0.9
Low	gr_1	Sand	0	0	1
Low	less_1	Clay	0	0.05	0.95
Low	less_1	Sand	0	0	1

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