Roger F. Auch

Nov 7, 2018

Land Change in the Piedmont Ecoregion

Acknowledgements

▪ Bruce Pengra, SGT, Contractor to USGS

▪ Kristi Sayler, USGS

▪ Janis Taylor, SGT, Contractor to USGS

▪ Jo Horton, Innovate!, Contractor to USGS

▪ Michelle Bouchard, SGT, Contractor to USGS

▪ Dan Zelenak, Innovate!, Contractor to USGS

Presentation Outline

▪ Goals of initial geographic LCMAP Assessments

▪ Land-Cover and Land-Use Change in the Piedmont Ecoregion- Previous Work

▪ Land Cover Classification Change in the Piedmont-Comparing the Reference and Map Data

▪ LCMAP Change Day (Spectral) Product & Classification Change in the Piedmont- Early Results

▪ Conclusions so far

The “Joe Friday” Approach

▪ What is the Rate of Change?

▪ What Changed?

▪ When did it Change?

▪ How much Changed?

▪ Where did it Change?

▪ What was the approximate cause of the Change?

“Just the facts…”

A new question…

▪ Can LCMAP find “conditional” (e.g. forest thinning) change that doesn’t cause a classification change?

▪ Can these questions be answered: ▪ How much of a land cover remained stable?

▪ How much had classification change?

▪ How much had change that didn’t result in a classification change, per year?

What Data are we using?

▪Version 1 Prototype LCMAP

Piedmont U.S. EPA Level III Ecoregion

Land Cover Trends Ecoregions and Sampling

Differences between LCMAP and LC Trends

▪ Wall-to-wall Mapping vs sampled mapping

▪ Annual change numbers vs interval-based assessments

▪ Multiple map products vs classified land cover/classified change only

▪ Sampling important to both projects

Land Cover Trends 1973-2000 for the Piedmont

▪ Overall spatial change 14.5% (-/+ 4.6%)

▪ Annual rate of change (derived from 4 intervals) 0.5% to 1.1%

▪ Number of classification changes: 1x= 8.8% (-/+2.2%), 2x= 5.2% (-/+2.6%), 3x= 0.4% (0.3%), 4x= 0.0%

▪ Leading types of interval-based change (overall): Forest to Mech. Disturbed 33.6%, Mech. Disturbed to Forest 27.0%, Forest to Developed 15.6%, Agriculture to Forest 6.7%, Forest to Agriculture 6.5%, All Others 10.7%

▪ Napton, D.E., 2016, Piedmont Ecoregion, in Sayler, K.L., Acevedo, W., and Taylor, J.L., Auch, R.F., eds., Status and trends of land change in the Eastern United States—1973 to 2000: U. S. Geological Survey Professional Paper 1794-D, p. 135-142, at http://pubs.er.usgs.gov/publication/pp1794D.

Land Cover Trends- “Mechanically Disturbed”

▪ “Land in altered and often unvegetated state owing to disturbance by mechanical (that is, human) means. Mechanically disturbed land is in transition from one land-cover class to another. Processes leading to mechanical disturbance include forest clearcutting, earth moving, scraping, chaining, reservoir drawdown, and other types of anthropogenically induced changes.”

Land Cover Trends 2000-2011 for the Piedmont

▪ Sampling redone with 40 10x10 km sample blocks

▪ Annual rate of change (derived from 2 intervals) 1.3% (+/- 0.3%)

▪ Leading types of change (interval based, results/uncertainty given in km2): Forest to Mech. Disturbed, Mech. Disturbed to Forest, Forest to Developed, Ag to Developed, Forest to Ag, Ag to Forest

▪ Auch, R.F., Napton, D.E., Sayler, K.L., Drummond, M.A., Kambly, S., and Sorenson, D.G., 2015, The Southern Piedmont’s continued land-use evolution, 1973–2011: Southeastern Geographer, v. 55, no. 3, p. 338-361.

LCMAP Annual Land Cover in motion for the Piedmont

Rate of Classification Change - LCMAP Reference

Mean for 31 years: 1.6%

Rate of Classification Change - Map at Reference Points

Mean for 30

years: 1.8%

Rate of Classification Change - Entire Map

Mean for 30

years: 2.1%

Area Estimates of Rate of Classification Change

Relationship of

Reference and Map

at the Reference

points with

Standard Errors

modified by change

found in entire Map

for that year

Piedmont Net Classification Change - Reference

Developed +6% Grass/Shrub -2% Tree Cover -4% Water +1%

all other classes <1%

Cropland

GrassShrub Tree Cover

Water Wetland

Reference 1985

Developed

Reference 2016

Developed Cropland

GrassShrub Tree Cover

Water Wetland

Piedmont Net Classification Change - Map at Reference Points

Developed +2% Cropland +1% Tree Cover -3% Water +1%

all other classes <1%

Map at Ref Pts 1985

Developed CroplandGrassShrub Tree CoverWater Wetland

Map at Ref Pts 2016

Developed CroplandGrassShrub Tree CoverWater Wetland

Piedmont Net Classification Change - Entire Map

Developed +1% Cropland +2% Tree Cover -2%

all other classes <1%

Entire Map

Developed Cropland

GrassShrub Tree Cover

Water Wetland

Entire Map

Devloped Cropland

GrassShrub Tree Cover

Water Wetland

Types of Classification Change, Overall - Reference

Types of Classification Change, Overall - Map at Reference Plots

Types of Classification Change, Across Time- Reference

Tree to Grass/ Shrub

Grass/ Shrub to

TreeTree to Develop

Grass/ Shrub to Develop

Ag to Develop

Grass/ Shrub to

Ag

Ag to Grass/ Shrub

Tree Cover to

Ag All Others Total

1985-1990 16 8 0 0 0 0 0 0 3 27

1990-1995 15 18 2 1 1 0 0 0 3 40

1995-2000 17 17 4 1 0 0 1 0 2 42

2000-2005 6 11 4 0 0 0 0 0 4 25

2005-2010 2 10 1 0 0 1 0 0 5 19

2010-2015 4 2 4 1 1 0 0 1 2 15

60 66 15 3 2 1 1 1 19 168

Types of Classification Change, Across Time- Map at Reference Points

Tree to Grass/ Grass/ Ag to Grass/ Shrub to Tree to Grass/ Shrub Ag to Shrub to Grass/ Shrub Tree Develop to Develop Develop Ag Shrub Tree to Ag All Others Total

1985-1990 9 13 2 0 0 0 2 0 3 29

1990-1995 12 14 2 0 0 0 0 3 1 32

1995-2000 20 10 1 1 0 1 0 2 4 39

2000-2005 13 13 2 0 0 0 2 0 2 32

2005-2010 14 13 1 0 0 0 0 1 2 31

2010-2015 7 13 1 0 1 0 0 0 5 27

75 76 9 1 1 1 4 6 17 190

Accuracy of Types of Change in the Piedmont

Producers’ Accuracy (Exact Year Matching)

▪ Stable Tree Cover 89%, Stable Water 72%, Stable Developed 63%, Stable Wetland 61%

▪ Stable Cropland 84%, Stable Grass/Shrub 9%

▪ Tree Cover to Grass/Shrub 27%, Grass/Shrub to Tree Cover 7%, Tree Cover to Developed 20%

Accuracy of Types of Change in the Piedmont

Users’ Accuracy (Exact Year Matching)

▪ Stable Tree Cover 90%, Stable Developed 71%, Stable Water 63%, Stable Wetland 63%

▪ Stable Cropland 30%, Stable Grass/Shrub 22%

▪ Tree Cover to Grass/Shrub 21%, Grass/Shrub to Tree Cover 6%, Tree Cover to Developed 27%

▪ Overall Accuracy 73.5%

Area Estimates of Change

▪ Annual pixel counts from Map products alone are not statistically robust

▪ LCMAP reference sampling is set up for national and large regional use,

smaller geographical areas may not contain enough samples for annual

estimates of specific types of change without further augmentation

▪ For the Piedmont for the LCMAP, with 349 completed out of the 495

national samples found there, annual rate of change and overall gross

change for leading types of change are doable

▪ Annual estimates for 3 leading changes (Tree Cover to Grass/Shrub,

Grass/Shrub to Tree Cover, and Tree Cover to Developed) can be done

but will have “holes” in them where there is not enough reference and

map information

Overall Spatial Classification Change

1985 - 2016• Overall 32.5%

• 1 change 14.4%

• 2 changes 12.8%

• 3+ changes 5.3%

Overall Spatial (Change Day) Change

1985 - 2016• Overall 49.3%

• 1 change 24.7%

• 2 changes 14.1%

• 3+ changes 10.5%

Annual (Change Day) Change Map Product

▪ Although most classification change is also found in the spectral change products, other, non-classification change are also included

▪ Using the Change Day product in conjunction with the classification change maps may allow quantifying how much other change occurs that could help answer the “how much of a land cover remained stable, how much had classification change, and how much had non-classification change” question asked at the beginning of the presentation

▪ It may be particularly useful in detailing how much overall forest disturbance or grassland/shrubland fires occurs

How to Possibly Analyze Annual (Spectral) Change Map Product

▪ Annual Reference Land Cover Classification - “Ref LC” in the following table

▪ Annual Reference Change Processes- “Ref chg” in the following table. The “stable” process is not used.

▪ Annual Map Land Cover Classification- ‘Map LC” in the following table

▪ Annual Change Day (Spectral) Map- “Map chg” in the following table

▪ Where “Ref chg” occurred by itself, that was not captured in this table, all other possible combinations were

Annual (Spectral) Change Product in relationship to these other LCMAP change metrics

all data

metrics

"YES"

Ref

"YES"

Map

"NO"

Map chg

"YES"

Map chg

& Ref chg

"YES"

Map LC

"YES"

Map LC

"NO"

Ref LC

"NO"

Ref LC

"NO",

Map chg

1 year

prior

Map LC

"NO",

Map chg

1 year

prior

Map LC &

Ref LC

differ

% of

total

(452)

4% 19% 17% 11% 7% 7% 6% 4% 2% 1%

Annual (Spectral) Change Product in relationship to these other LCMAP change metrics

Annual (Spectral) Change Product in relationship to these other LCMAP change metrics

▪ The Ref chg & Map chg “yes” could provide the basis for at least non-classification tree cover disturbance AND an accuracy assessment using certain Ref chg processes

▪ Land covers could also be tested with other change processes, such as “fire” with grass/shrub and tree cover land covers

▪ The Reference dataset’s land use check boxes for the Cropland land cover class might also be useful to see how changes among them match with the Map chg product

Conclusions

▪ LCMAP does well in capturing regional land cover composition

▪ LCMAP captures interannual changes in the rate of land cover classification change

▪ LCMAP captures the leading stories of change in the Piedmont, especially forestry and to lesser extent increased urbanization and changes among tree cover and agricultural land uses

▪ LCMAP spectral change product holds promise for finding some non-classification change events such as certain disturbances

▪ Initial LCMAP geographic assessments just the beginning of many types of assessments that can be done with LCMAP map products

LCMAP: For more information

▪ Existing web page is being reworked:

https://eros.usgs.gov/science/land-change-monitoring-assessment-and-projection-lcmap

▪ USGS EROS Center Customer Service:

▪ Email: custserv@usgs.gov

▪ Phone: 1-800-252-4547

▪ Social media: USGS/EROS twitter and facebook