BushfireConf 2015 - 5. Where has all the fire gone? Quantifying the spatial and temporal extent of fire exclusion in Byron Shire NSW

WHERE HAS ALL THE FIRE GONE?

Quantifying the spatial and temporal extent of fire exclusion in

Byron Shire NSW

Andy BakerWildsite Ecological Services

Overview

Fire Exclusion & Vegetation Change

GIS Analysis Methods

Results - Fire exclusion in Byron Shire

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3 Key Messages

1. Nearly half of Byron Shire’s biodiversity needs regular fire to maintain suitable habitat

Click icon to add picture2. Without regular fire,

habitats can change rapidly 3. If habitat becomes unsuitable,

localised extinctions follow

Fire Exclusion & Vegetation Change

• Worldwide phenomenon

• Two main processes:

1. Treeless ecosystems forests2. Open forest rainforest

Wet Tropics Bioregion

• 25% (>100 000 ha.) open forest/woodland rainforest since 1950’s

• 2014 study mapped 2 million ha.(Stanton et al. 2014)

Major open forest types

Time

Rainforest

Climatic Potential

Fire

Why is Change Happening?

5 years

Grassland

Time

Fire interval governs structure

20 years

Dry Sclerophyll

Forest

Time

Fire interval governs structure

100+ yearsor

No fire

Rainforest

Time

Fire interval governs structure

HeathlandGrassland

Wet Sclerophyll

ForestDry Sclerophyll

Forest

Fire-dependent vegetation

• Most species need fire for recruitment

Click icon to add pictureTreeless Ecosystems Forests

Click icon to add pictureTreeless Ecosystems Forests

Click icon to add pictureTreeless Ecosystems Forests

Click icon to add pictureTreeless Ecosystems Forests

Click icon to add pictureTreeless Ecosystems Forests

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19842012

Open Forests Rainforests

Fire-resistance threshold

• Rainforest trees not removed by fire (manual removal?)• Rainforest regrowth quickly resumes transition process after fire

Fire-suppression threshold

• Understorey unlikely to carry fire (prescribed or wildfire)• Loss of understorey diversity

Is fire-exclusion a problem in Byron Shire?

METHODS - GIS Analysis

Native Vegetation

Endangered Ecological

Communities

Coastal Wetlands

Coastal Koala Habitat

Time since last known fire

Fire Exclusion Status

Fire-intervals guidelines for

vegetation types

Mapping Time Since Last Known Fire

Step 1: Combine fire records

1974 - 2014

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Mapping Recommended Fire Intervals

Step 1: Combine vegetation datasets

Click icon to add pictureStep 2: Exclude exoticvegetation

Click icon to add pictureStep 3: Assign to vegetation formations

after Walker & Hopkins 1984; Beadle & Costin 1952

Click icon to add pictureStep 4: Determine fire relationships

Click icon to add pictureStep 5: Assign recommended fire intervals

• Specific to the region

• Recommended by Northern Rivers Regional Biodiversity Management Plan (DECC 2010)

• Factor in risk of vegetation change resulting from fire exclusion

Fire Interval Guidelines - NSW North Coast and SE Queensland

compiled from Watson 2001, Watson 2006 and Tierney & Watson 2009

Step 5: Assign fire intervals

Results

RESULTS

Fire-dependent Native Vegetation

Long-term Fire Exclusion across

Key Conservation Values

RESULTSEndangered Ecological

Communities(Fire-dependent)

Long-term Fire Exclusion across

Key Conservation Values

RESULTS Coastal Wetlands

Long-term Fire Exclusion across

Key Conservation Values

RESULTS Coastal Koala Habitat

All koala feed trees require fire for widespread recruitment

So what is their relative importance in Byron Shire?

High vs Low Frequency Fire

High Frequency Fireo listed as Key Threatening Process (TSC Act)o routinely listed as a threat in ecological assessments

Low Frequency Fireo Not listed as KTPo Rarely considered in ecological assessments

Inappropriate Fire Frequency

What about high frequency fire?

Fire-exclusion is spatialy extensive…

but by how long are thresholds exceeded?

Temporal Extent

?

No Data

species & habitat decline

10 yrs

Temporal Extent - formations

Total for Byron Shire

942Fire-dependent communities430 (46%)

Impact on Floristic Diversity

Flora species by height class

0-2m

2-5m

5-50m

600 20 40

Fire-dependent Species (%)

Hei

ght C

lass

(m)

6%

100

initial shading zone

84%

6%

10%

80

Regional Patterns:OEH analysis

What about the broader region?

ConclusionFire exclusion:• major threatening process affecting Byron Shire’s biodiversity• potentially widespread in similar regions along east coast Restoration complicated by:• encroaching trees that have become fire resistant, and • loss of flammable understorey to carry ecological burns

Further research:• What is the extent of fire-exclusion in other regions?• How quickly are critical thresholds reached in diff. ecosystems?

ReferencesBeadle, N.C.W. and Costin, A.B. (1952) Ecological classification and nomenclature. Proceedings of

the Linnean Society of New South Wales 77: 61-82.

Stanton, P., Stanton, D., Stott, M. & Parsons, M. (2014) Fire exclusion and the changing landscape of Queensland’s Wet Tropics Bioregion 1. The extent and pattern of transition. Australian Forestry, 77, 51–57.

Tierney, D., & Watson, P. (2009). Fire and the Vegetation of the Namoi CMA. Nature Conservation Council of NSW, Newtown.

Walker,J. & Hopkins,M.S.(1984). Vegetation. In R.C.McDonald, R.F.Isbell, J.G.Speight, J.Walker & M.S.Hopkins(eds). Australian Soil and Land Survey Field Handbook. pp44-67. Inkata Press, Melbourne.

Watson, P. (2001). The role and use of fire for biodiversity conservation in south-east Queensland: Fire management guidelines derived from ecological research. Nature Conservation Council of NSW, Newtown.

Watson, P. (2006). Fire frequency guidelines and the vegetation of the Northern Rivers region. Nature Conservation Council of NSW, Newtown.

Read more...

Baker, A and Catterall, C. (2015) Where has all the fire gone? Quantifying the spatial and temporal extent of fire exclusion in Byron Shire, Australia. Ecological Management & Restoration 16. doi: 10.1111/emr.12161

Ecological Management & RestorationVolume 16, Issue 2, May 2015

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