Detecting Grassland Change

Anne M. Smith Agriculture and Agri-Food Canada, Lethbridge, Alberta, Canada.

State and Trends of Canadian Grasslands Workshop,

Saskatoon, SK. June 26-27th 2012.

Canadian Grasslands

Grassland Cultivated crop

C emission 26 Mg ha-1

C sequestration

0.5 Mg ha-1 year-1

Photographs courtesy of

G. Bourgeois, M. Didkowsky,

R. Bourchier, J. Nicholsen, G. Larson, C. Kloppenburg. 2

Status of grasslands in the Northern Great Plains

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Status of grasslands in the Northern Great Plains

Source: Samson, F. B., F. L. Knopf and W.R. Ostlie. 1998. Grasslands. In Status and Trends of the

Nation’s Biological Resources — Volume 2 pp. 437-472.

Grassland Type Area (km2) Decline

(%) Historic Current

Tallgrass Prairie 677,300 21,548 96.8

Mixed-grass Prairie 628,000 225,803 64.0

Short-grass Prairie 181,790 62,115 65.8

TOTAL 1,487,090 309,467 79.2

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Status of grasslands in the Canadian Prairies

Source: Samson, F. B., F. L. Knopf and W.R. Ostlie. 1998. Grasslands. In Status and Trends of the

Nation’s Biological Resources — Volume 2 pp. 437-472.

Grass type Location Past area

(km2)

Current

area (km2)

Decline

(%)

Tallgrass Prairie Manitoba 6,000 3 99.9

Mixed-grass Prairie Manitoba 6,000 3 99.9

Saskatchewan 134,000 25,000 81.3

Alberta 87,000 34,000 60.9

Short-grass Prairie Saskatchewan 59,000 8,4000 85.5

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Developing Earth Observation Tools to Measure the Current and Future Spatial Extent and Productivity in Grasslands of Western

Canada

the spatial extent and fragmentation of grasslands,

the net primary productivity of grasslands (health),

invasive plant species on grasslands, using leafy spurge as a model.

Objectives: To develop multispectral, hyperspectral and radar earth

observation tools to address mapping and quantification of:

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SPATIAL EXTENT AND

FRAGMENTATION

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Grassland spatial extent and fragmentation

Spatial databases of native grassland extent

Agriculture and Agri-Food Canada grassland mask

Agriculture Financial Services Corporation grassland mask

Alberta Native Prairie Baseline (~1993)

Alberta Grassland Vegetation Inventory (2006-2014)

Alberta Primary Land Vegetation Inventory (2014-?)

Inventory updates

Landsat Data Continuity Mission (2013), Sentinel missions

(2013), Radarsat Constellation Mission (2016-2017)

Historic changes

Landsat legacy (1982-2011)

Validation data

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Grassland spatial extent and fragmentation

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False colour composite Landsat5 TM images acquired in July 1999 for the Onefour test site

and the corresponding classified image showing grassland versus crop land

Legend

Crop

Range

River

Lakes

Grassland

change

(1999-2005) Newell, Taber,

Cypress and

Forty Mile

County.

Highlights

areas of

change

Validation? lack of

historic

ground

data

Local

knowledge

County Unchanged To crop To Grassland Total

area in ha (% change)

Newell 590714 (95) 23241 (4) 9867 (2) 623823

Cypress 884880 (95) 34339 (4) 9961 (1) 929180

Taber 413384 (96) 11185 (3) 4439 (1) 429009

Forty Mile 424616 (98) 4724 (1) 3638 (1) 432978

Grassland spatial extent and fragmentation

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“RADARSAT-2 Data and Products © MacDONALD, DETTWILER AND ASSOCIATES LTD. (2009) – All Rights Reserved”

“RADARSAT is an official mark of the Canadian Space Agency” 11

Grassland spatial extent and fragmentation

Grassland spatial extent and fragmentation

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Native Prairie Vegetation Inventory

1990-1993

1:30,000 aerial photography

¼ section based

% ground cover of tree, shrub,

graminoid, riparian, lake or wetland

Grassland Vegetation Inventory

colour infrared digital airborne imagery 0.5 m

Comprehensive biophysical, anthropogenic and

land use inventory

polygon-based, 5.0 ha for upland site types and

1.0 ha for wetland site types.

Accuracy estimated at >90%

Image courtesy of Barry Adams, Alberta Environment and Sustainable Resource Development 14

15 Image courtesy of Barry Adams, Alberta Environment and Sustainable Resource Development

Updated GVI

2007 SPOT Image 2006 GVI

GVI updates through satellite imagery?

Database

Record

Add/edit/delete

Slides courtesy of Barry

Adams AESRD 15

“Spectral fingerprinting” using 2005 and 2006 Hyperion and

vegetation indices

Slide courtesy of M. Hill, University of North Dakota

Darwin, Northern Territory, Australia

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“Spectral fingerprinting” using 2005 and 2006 Hyperion and

vegetation indices

Slide courtesy of M. Hill, University of North Dakota

Darwin, Northern Territory, Australia

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Landsat (NASA)

2013

11 bands

15/30/100m

185 km

Sentinel (ESA)

2013

13 bands

10/20/60m

290 km

10 days

“Spectral fingerprinting” using Hyperion and vegetation indices

to update GVI?

Hyperion

220 bands

30 m

7.5 km

Landsat Data

Continuity mission

2013

11 bands

15/30/100m

185 km

Sentinel-2

2013

13 bands

10/20/60m

290 km

10 days

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Oil and Gas-GIS Analysis

2001 NWA Infill Project

19 Image courtesy of Barry Adams, Alberta Environment and Sustainable Resource Development

CFB Suffield NWA (pre-infill--1997)

20 Image courtesy of Barry Adams, Alberta Environment and sustainable Resource Development

CFB Suffield NWA (post-infill--2001)

21 Image courtesy of Barry Adams, Alberta Environment and sustainable Resource Development

Lost grazing (by area): loamy (12.5%), sands (11.1%), choppy sandhills (1.8%) 22

INVASIVE PLANT SPECIES

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Invasive plant species

Invasive plant species in Canada

116 in Prairie region

Economic impacts

a selection of 16 invasive alien species in Canada estimated

to be cost $13-34 billion per annum (Colautti et. al. 2006).

Livestock impacts

reduction in forage

unpalatable or toxic

Ecological aspects compete for water, other resources

drive valuable native species to local or

regional extinction (Pimentel et al. 2000 )

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Image courtesy of Barry Adams, Alberta Environment

and Sustainable Resource Development

Oil and gas reclamation

non-native species prior 1994

crested wheatgrass (Agropyron cristatum)

a highly invasive species

Rolfson, D.R. 2008.

SPOT 5

July 20, 2007, July 29, 2008.

10 m resolution

multispectral

soil adjusted vegetation index,

modified soil adjusted vegetation

index, exponent normalized difference

moisture index (after Zhou, 2007)

Mapping invasive weed species

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