grassland: what we need it and what do we know? · observations? 1. reviews reference location...

Presenters:

Brian McConkey and Xiaoyu Wang

Carbon Stock Changes on Canada’s

Grassland:

What we need it and what do we know?

2

Canada’s National Greenhouse Gas Inventory

• Reporting greenhouse gas (GHG) emissions and removals is a

requirement under the United Nations Framework Convention on

Climate Change (UNFCCC)

– Canada submits a National Inventory Report of GHG

emissions annually

3

Reporting Requirements - IPCC

• Estimating GHG must follow Good Practice Guidance from Intergovernmental Panel on Climate Change (IPCC):

• “ensures that estimates of carbon stock changes, emissions by sources, and removals by sinks, even if uncertain, are bona fide estimates, in the sense of not containing any biases that could have been identified and eliminated, and that uncertainties have been reduced as far as practicable given national circumstances”

• Moving to a higher Tier of estimation methodology is Good Practice

• Tier 1 estimation methods are defaults that are meant to be applicable in all countries

• IPCC has produced these methods, primarily intended for developing countries and/or relatively unimportant emissions/removals

• Tier 2 estimation methods have similar structure to Tier 1 methodology but are country-specific

• Each country produces its own parameters, classes, etc.

• Tier 3 estimation methods have completely country-specific methods and structure

• Example would be process modelling of GHG emissions and removals

4

Land

• IPCC Good Practice is to divide land into six classes

– Forest

– Cropland

– Grassland

– Settlement (include transportation and utility corridors and mineral

exploitation)

– Wetlands

– Other (ice, bare rock, bare sand)

5

Grassland and Cropland

• Canada defined agricultural grassland for purposes on National Inventory Report of GHG as natural areas or natural unimproved pasture (native grass) used for grazing domestic livestock – Grassland only if will not naturally convert to forest if

abandoned excepting continuing fire suppression

– Therefore, only exist in semiarid regions (5.7 M ha)

• Effectively rangeland in Brown and Dark Brown soil zone in Alberta and Saskatchewan and these chernozemic soils in interior of BC – Mixed grass prairie

• Grassland area relatively stable and simplifies determining land-use changes involving grassland

• Cropland is all agricultural land that is not grassland – Most of Canada’s grazing is on “cropland”

Remaining Prairie Grassland

7

8

What do we need to know?

• Canada has not estimated C stock changes on its

grassland

– Difficult and confusing

• UNFCCC reviewers want estimates now !

• What is the state and trends of Canada’s grassland and

what does that tell us about C stock changes?

• Immediate focus is on natural mixed-grass grasslands

– Actually need C stock change estimates for all of Canada's

grasslands

– Current grasslands outside of semiarid climates not estimated

specifically but included within “cropland” so effectively

estimating no C stock changes on those grasslands.

Environmental Goods and Services

• Grassland provides many important environmental goods and

services (EGS)

– Water quality, biodiversity, air quality, soil quality

• How to have society reimburse land stewards for EGS?

• GHG emission offsets from GHG removals (C sequestration)

or from GHG emission reductions compared with what would

have occurred represent the first environmental service

available for payment

– Alberta and emerging Saskatchewan provincial offset systems

– GHG offset quantification test case for systems to reimburse for

EGS

9

Beef production is GHG intensive

• “Livestock’s Long Shadow”

– Food and Agricultural Organization 2006 report

– Livestock have much negative environmental impact

– Beef is particularly identified for contributing to GHG

emissions

• Liebig et al. 2010 (Grazing Management Contributions

to Net Global Warming Potential: A Long-term

Evaluation in the Northern Great Plains. J. Environ.

Qual. ) shows that calf production on native range is

carbon negative (i.e. C change > total emissions)

– Save the planet - Eat beef (?)

10

Quantifying GHG for Grassland Management:

IPCC Tier 1

• C stock changes is

– biomass change + dead organic matter change + soil organic carbon (SOC)

• Biomass and dead organic matter by change in stock or

change in gain-loss balance

• SOC most complex:

11

Quantification

• To implement IPCC: how to determine area of

moderately and severely degraded over time?

– Change in these categories more important than knowing

areas at one time

• But want to put focus on direct anthropogenic emissions

– Direct = from deliberate human management

– Not focus on weather or natural disturbances

– Not focus on indirect anthropogenic from human-induced

climate change or increased atmospheric N deposition

• Are there alternate methods to quantify GHG effects

based on human management directly?

16

Litter

SOC

No Litter

Grazing

Vegetation

Utilization

The SOC Conceptual Model

How well does the conceptual model match

observations? 1. Reviews

Reference Location Results

Pineiro et al.

2010

World

literature

Inconsistent effect of grazing on

SOC, better retention of N

increases SOC

Derner and

Schuman 2007

Mostly W.

North

America

Short-term (20 yrs) grazing

increases SOC but no change in

SOC after long-term grazing (80

yrs)

Milchunas and

Lauenroth 1993

Worldwide Inconsistent effect of SOC from

grazing, ANPP decreases with

increasing grazing

18

How well does the conceptual model match

observations? 2. Studies Western North America

Reference Location Grassland Comparison Duration Results

Li et al.

2012

Alberta Rough fescue None versus

moderate vs

heavy

58 yrs No difference

Shrestha

et al.

2008

Wyomin

g

sagebrush

steppe

Grazing vs.

none


Gill et al.

2007

Utah. mountain

meadows

Grazing vs.

none


Dormaar

et al. 1977

Alberta Mixed

Grass,

Fescue

Grazing vs

none

19, 20

yrs

No difference

19

More Studies Western North America


Silver et

al. 2010

California perennial

grasslands

Grazing vs.

none

various,

lit

review

No difference

Henderso

n et al.

2004

9 sites S.

Alberta

Fescue to

dry mixed

grass

Grazing vs

none

23-71

yrs

No difference

Naeth et

al. 1991

Alberta Mixed

grass,

parkland

fescue, and

foothills

fescue

None vs

grazing:

intensity and

timing

21,12, 36

yrs

No difference

20

Still More Studies from Western North America


Wilms et

al. 2002

Alberta 15 sites

mixed grass

Grazing vs

none

70 yrs No difference (trend to

lower with grazing,

especially Sz soils)

Dormaar

et al. 1997

Alberta Mixed grass None versus

moderate

grazing

5 yrs No difference but

trend to grazing lower

Biondini et

al. 1998

North

Dakota

Mixed grass None vs

moderate vs

heavy

7 yrs No difference but

trend for heavy lower

21

Even More Studies from Western North America


Bauer et

al. 1987

North

Dakota

4 sites, mixed

grass

Grazed vs

none

c. 75 yrs None > grazing

Derner et

al. 2006

Kansas

and

Colorado

Tallgrass,

midgrass,

shortgrass

No vs grazing 25, 96,

54 yrs

Tallgrass: grazing less

Midgrass no

difference

Shortgrass: grazing

more

22

Yet more….


Frank et al.

1995;

Wienhold et

al. 2001;

Liebig 2010

North

Dakota

Mixed grass None vs Light vs

Heavy

75 and 87 Heavy = None >

Moderate after 75 yrs;

Trend only after 87

years;

Heavy > Moderate (mass

equivalence after 87

years)

23

Still coming….


Schuman et

al. 1999;

Ganjegunte

et al. 2005

Wyoming Mixed grass None vs Light vs

Heavy

12&20

yrs

Light=heavy>none after

12 yrs

Light>Heavy=none after

20 yrs

Ingram et

al. 2008

Wyoming Mixed grass None vs light vs

moderate

20 yrs Light > None > Heavy

Manley et

al. 1995

Wyoming Mixed grass No vs light vs

heavy versus

rotational heavy

vs deferred

heavy

10 yrs Grazing > none

Rotational heavy less

than other grazing

Smoliak et

al. 1972

Alberta Mixed grass None vs light vs

moderate vs

heavy

19 yr Heavy > none; others

intermediate but nearer

no grazing

24

Enough already


Schuman

et al. 1999;

Ganjegunt

e et al.

2005

Wyomin

g

Mixed grass None vs Light

vs Heavy

12&20

yrs

Light=heavy>none

after 12 yrs

Light>Heavy=none

after 20 yrs

Ingram et

al. 2008

Wyomin

g

Mixed grass None vs light

vs moderate

20 yrs Light > None > Heavy

Reeder et

al. 2004

Colorado Shortgrass None vs. light

vs. heavy

56 yr Heavy>light=none

(soil inorganic carbon

also increased

significantly?)

25

Range Condition?

Reference Location Grassland Comparison Duration SOC Results

Henderson et

al. 2004

9 sites S.

Alberta

Fescue to dry

mixed grass

Excellent

(exclosure) to

poor-good

grazed

23-71 No difference

Dormaar

and Wilms

1990

Alberta Mixed grass Poor vs good

conditions

Not

specified

Lower for good

condition (species shift

to blue grama)

26

Introduced Species?


MacDougall

and Wilson,

2011

Saskatchewan Bouteloua-

Stipa

Crested wheat

invaded native

vs. native

50+ yrs No difference

Henderson

and Naeth

2005

8 sites in

Alberta and

Saskatchewan

Mixed grass Crested

wheatgrass

invaded native

vs native

10-65 yrs No difference

Broersma et

al. 2000

3 sites in

southern

interior of

B.C.

Mixed grass Seeded crested

wheat onto

native vs native

14-60 yrs No difference

Mortenson et

al. 2004

South Dakota Mixed grass Alfalfa

interseeded vs

none

3-35 yrs Alfalfa increased SOC

(initial gains 1.5 t

C/ha/yr!)

27

Burning?


Bremer

and Ham

2010

Kansas Tallgrass Annual vs

restricted

burning

3 yrs Burning caused net

loss of C

Anderson

and Bailey

1980

Alberta Parkland

fescue

Burning vs

none

Burning caused

increase in SOC

28

Shrubs?


Bai et al.

2009

9 sites in

Saskatchew

an

Mostly

mixed grass

Snowberry

patch vs

grassland

? Ecosystem C

snowberry>grass

SOC trend

snowberry>grass

29

Litter

SOC

No Litter

Grazing

Vegetation

Utilization


Native grassland is very resilient to grazing pressure

with regard to total SOC

- Dormaar (1997)

31

Litter

SOC

No Litter

Grazing

Vegetation

Utilization

The Resistant SOC Conceptual Model

C change over time ?


LeCain et

al. 2002

Colorado Shortgrass Flux for No vs

light vs heavy

2yrs on

56 yr

history

Not consistent sink or

source, no consistent

effect of grazing

Haferkamp

and

MacNeil

2004

Montana Mixed grass Flux for No vs

grazing

3 yrs Not consistent sink or

source or consistent

effect of grazing

Liebig et

al. 2010

North

Dakota

Mixed grass 1959 vs 2003,

grazing

management

same since 1916

44 yrs 0.4 t C/ha/yr for both

moderately and heavily

grazed!?!?!?

33

Soil CH4 and N2O emissions?

• N2O

– Any management that affects C affects N and thereby affects N2O

emissions

– Any management that affects cattle urine production affects N2O

emissions

– Effects not clear but fluxes generally small and so N2O consumption by

soil also needs to be included

• CH4

– Grassland soils are net consumer of atmospheric CH4

– No clear effect of management but can become important offset of

grazing enteric fermentation emissions, especially at lower stocking

densities (Liebig et al. 2010, 1/3 of enteric emissions for moderate

grazing intensity)

34

Grassland in

northern China

What can we learn from other semiarid cold temperate

regions?

China’s grassland contributed 6-8% total world grassland area.

China’s grassland carbon contributed to 9-16% world grassland carbon.

Meadow and steppe account for 2/3 of total grassland carbon.

Species switching

Reference Location Grassland Comparison Species change

Li (1993)

Wuyunna (1999)

Wang (2002)

Xilingol

Inner Mongolia

Typical steppe Grazing intensity

gradient, heavy

grazing

Species richness decreased

A. Chinense decreased,

A. frigida increased,

Unpalatable species

increased

Wang (2001) Heilongjiang Meadow steppe Grazing intensity

gradient, heavy

grazing

More creeping-type species

appeared, special

heterogeneity

increased

Jia (2000) Ordos plateau Desert steppe Grazing intensity

Light grazing,

moderate grazing,

Continuous open

grazing

Species diversity decreased

semi-shrub

Artemisia songorica domined

in the open plot

Grassland carbon change based on observations


Wiesmeier

,Liu, He and

Han (2012)

He(2009,201

1),

Zhao (2007)

Inner

Mongolia

Typical steppe Continuous

grazing vs. grazing

exclusion

Grazing intensity:

Light, moderate,

heavy grazing

3-30 yrs Decreased after long term

grazing,

Decreased with grazing

intensity increasing.

Cheng, Liu

(2012)

Fang (2010)

Li (2008)

Yong (2005)

Loess

plateau,

Inner

Mongolia

Desert steppe Continuous

grazing vs. grazing

exclusion

Grazing intensity:

Light, moderate,

heavy grazing


grazing,



Cheng

(2012)

Han (2008)

Wu (2010)

Loess

plateau

Qinghai-

Tibetan

Plateau

Northern

inner

Mongolia

meadow steppe

Alpine meadows

Continuous

grazing vs. grazing

exclusion

Grazing intensity:

Light, moderate,

heavy grazing


grazing,



Litter

SOC

No Litter

Grazing

Vegetation

Utilization


Landscape of different grazing intensity on Typical steppe

No grazing Light grazing

Moderate grazing Heavy grazing

Landscape of different grazing intensity on Dessert steppe

No grazing Light grazing

Moderate grazing Heavy grazing

Biodiversity loss

Potentilla acaulis

Over-grazing resulted in a reverse

succession of grassland

Artemisia

frigida

Previous

Current

Severe degradation has happened across

grassland areas in Inner Mongolia in recent

decades due to improper management and

climate change.

Causes of grassland degradation:

-Overgrazing

-Cultivation without good management

-Collection of shrubs and dig medical plants

-Mining and road construction

Even worse Sand storm

Challenges we are facing to

44

Carbon storage estimation

Carbon storage changes on “time sequence”

Source or sink?

How it is in “previous years” and in “future” ?

Climate change

Management

Challenge 1,

Where is the grassland exactly located?

Research area define

What “type” of grassland?

45

Challenge 2,

Grassland management history?

Grazing animals, Stocking rate, distribution, Grazing length (years),

Grazing system

Deferred, Rotational, Seeded, Fertilizer, etc.

Direct way to estimate grassland carbon state and trend:

Challenge 3,

Grassland carbon estimation based on actual measurement (survey)

Sampling difficulties (Fragmentation, so many patches)

The reasonable number of sampling sites to represent the “whole”

Time, labour and money cost! - infeasible

We are lacking of carbon data in previous year (20-50 years ago)

Indirect way to estimate grassland carbon state and trend:

Challenge 4,

Remote sensing

build up a relation between a remote sensing indicators (NDVI, LAI etc) and

grassland carbon

technical issues, limitation

Modelling

Century etc.

validation!

Integrated approaches

Combine multiple sources of data for predictive mapping

46

47

NDVI 1988 to 2009 Ecorgions 159 and 157

Growing Season (May -September) Average NDVI for

Pastures and Grasslands

Ecoregions 159 and 157 in Saskatchewan

3000

3500

4000

4500

5000

5500

1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012

Year

ND

VI

NDVI-Pasture NDVI-Grassland

Li, Huffman et al. (in preparation)

48

NDVI and Soil Organic Carbon

• Recently literature has revealed a positive relationship

between SOC stock and NDVI

Kunkel et al. 2011

Is there a grazing “sweet spot”?

• Where grazing is

– sustainable,

– economically viable (and favoured), and

– maintains or increases SOC

– Satisfies all social and environmental goals

• Want to have grassland management categorization system for

GHG purposes that makes sense for other grassland management

outcomes

Hierarchial system

Capture management, history, type, etc.

“We are still seeking the effective approach to reach the balance of

ecological, economic and social!” - Fang

49

Ongoing additions of “naturalized” pasture to

grassland

– Pastures established on once cultivated land that are

managed similar to natural vegetation

– C stock still increasing from this land area as move

towards native SOC levels

– Fair bit known on SOC dynamics but

• How much grassland of different SOC states,

durations under grass, and plant communities?

50

Concluding Thoughts

• Canada must have estimate of C change on defined

“grassland” within 12 months!

• Are Canadian grasslands and GHG source or sink?

• How do we best estimate whether source or sink?

– Short term

– Long term

• How do we best develop quantification methodologies

that support attainment of our other objectives for

grassland?

– Help reach the “sustainable sweet spot”

51

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Thank You.

grassland: what we need it and what do we know? · observations? 1. reviews reference location...

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