A Comparison of Soil Condition, Vegetation Communities, and Soil Redox Characteristics of Surface

Mined Wetlands and Natural Wetlands in Southern Illinois

Blair Borries1, Karl W. J. Williard2, Jon Schoonover2, and Samuel Indorante3

1M.S. candidate – Southern Illinois University-Carbondale2Professor of Forestry– Southern Illinois University-Carbondale

3Soil Survey Leader – USDA-NRCS

Soil Properties of Restored Wetlands vs. Natural Wetlands

NATURAL WETLANDS

SOM

ρ b

C

N PRESTORED W

ETLANDS

REST

ORE

D W

ETLA

NDS

Purpose: Evaluate the soil biogeochemical function and herbaceous vegetation of wetlands restored on surface mines

• Do mined wetland soils retain or recover levels of nutrient and organic matter pools equal to natural wetlands?– as measured by the following parameters:

• Soil Organic Matter (SOM), Soil C, Soil N, Soil P, C/N ratio

• Do soil nutrient organic matter pools change with time in mined wetlands– as measured by tests of trends by soil age in the following parameters:

• SOM, C, N, P, and C/N ratio

• Do mined wetlands have the same hydrology as natural wetlands?– as measured by IRIS tubes– As measured by the frequency and duration of soil saturation in

wetlands• Do mined wetlands have the same vegetation as natural wetlands?

– as measured by the following parameters:• Taxa richness, Wetland status prevalence index, % bare soil

Study Area: Before and after mining

!.

!.

!.^

^

^^

^

^

^^

^^^

^^

^

^^^

^

Seasonal High Water Level

Seasonal High Water Table

< 0.3 m

0.5 m

0.15 m

0.15 m

0.15 m

0.15 m

0.10 m

Legend^ Sample Point

!. Monitoring Well

Seasonally Saturated Soil

Seasonally Inundated Area

Monitoring Well

Soil Sample: 0-0.15 m

Soil Sample: 0.15-0.30 m

Soil Sample: 0-0.10 m (bulk density)

IRIS tube

12 Wetland Areas4 NW

4 MPW4 MBFW

Study Design: Sampling plan

In each Wetland Area

9 transectsOne upper and one lower sample point36 Soil Samples Each SP split into 0-15 and 15-30 cm depths 18 vegetation plots9 IRIS Tubes3 Monitoring Wells

!.

!.

!.^

^

^^

^

^

^^

^^^

^^

^

^^^

^

Seasonal High Water Level

Seasonal High Water Table

< 0.3 m

0.5 m

0.15 m

0.15 m

0.15 m

0.15 m

0.10 m

Legend^ Sample Point

!. Monitoring Well

Seasonally Saturated Soil

Seasonally Inundated Area

Monitoring Well

Soil Sample: 0-0.15 m

Soil Sample: 0.15-0.30 m

Soil Sample: 0-0.10 m (bulk density)

IRIS tube

Study Design: Transect x-section

Soil properties vary depending on topographic position - sampling was split into upper and lower sample points

Methods: Soils• Samples collected June-August 2012• ρb and gravimetric soil moisture (GSM) collected with an impact

driven corer with a known volume• All other samples were collected with a 5 cm diameter auger,

air dried and crushed• Samples were analyzed for SOM, Bray II P, and CEC by Brookside

labs• C, N, and C/N analyzed with a total C/N analyzer at SIUC• ρb and GSM were measured by oven drying impact corer

samples• Soil texture was measured by hydrometer method

Methods: Vegetation and hydrology

• Percent cover of each herbaceous species and % bare area in a 0.25 m2 plot was estimated according to Daubenmeier (1954) at each SP

• Canopy cover from densiometer• Taxa richness (TR) and wetland plant prevalence index (PI)

was also calculated• IRIS tubes created according to Jenkinson and Fransmeier

(2005), analyzed with gridded contact paper according to Rabenhorst (2011)

• SP surveyed with total station and tied to RTK-GPS vertical benchmarks

Calculations: Hydrology• Hydrology variables: inundation (IN) and saturation

(SAT) count– Functions of groundwater (GW) elevation and difference

in elevation between SP and associated monitoring well (well)

– Assumptions: GW elevation is equal across a block of transects associated with a well

Well GW Depth = Well elevation – depth to GW (from collar)

SP GW Depth = SP elevation – Well GW Depth

IN count = # times GW > SP elevation

SAT count = # times GW was within 30 cm of SP elevation

Methods: Statistics

• Data were separated by location (upper or lower) and depth (0-15 cm or 15-30 cm)– Treatments were compared using a one-way

ANOVA (PROC GLM in SAS) model or the Kruskal-Wallace rank-sum test (soil N and C/N)

– Trends by soil age in MW were tested using a linear regression test when the same between MPW and MBFW and a step-trend ANOVA/K-W test when different between MPW and MBFW

Wetland area

Treatment Class Lat (dd) Long (dd) Soil Age

(years) Size (km2) Watershed (km2)

GAL1 MBFW 38.080518 -89.546028 28 3.21E-03 4.08E-02

GAL2 MBFW 38.078802 -89.542034 28 4.65E-03 1.23E-02

GAL3 MBFW 38.079559 -89.545478 28 1.05E-03 5.25E-02

GALC1 MPW 38.058720 -89.532437 25 9.36E-03 2.87E-02

GALC2 MPW 38.055909 -89.531824 25 3.39E-02 5.51E-02

BON1 MBFW 38.057239 -89.525484 21 8.67E-03 3.47E-02

BONC1 MPW 38.062799 -89.521813 19 1.12E-02 6.72E-02

BONC2 MPW 38.060407 -89.523414 19 1.23E-02 7.87E-01

LGAL1 NW 38.018040 -89.439554 N/A 1.21E-02 3.70E-02

LGAL2 NW 38.017704 -89.436491 N/A 8.73E-03 2.35E-02

LGAL3 NW 38.026255 -89.435087 N/A 2.04E-03 1.26E-02

LGAL4 NW 38.026991 -89.431518 N/A 2.50E-03 1.36E-02

Soil age ranges from 19-28 years

RESULTS/DISCUSSION

Photo: Jack Nawrot

SOM: Comparisons among treatments at different sample locations and depths

SO

M (%

): 15

-30

cm

0.0

0.5

1.0

1.5

2.0

2.5

SO

M (%

): 15

-30

cm

0.0

0.5

1.0

1.5

2.0

2.5

SOM in Upper Transect Points

NW MPW MBFW

SO

M (%

): 0-

15 c

m

0.0

0.5

1.0

1.5

2.0

2.5

3.0

SOM in Lower Transect Points

NW MPW MBFW

SO

M (%

): 0-

15 c

m

0.0

0.5

1.0

1.5

2.0

2.5

3.0a

a

b

aa a

a

b

c

a

b

c

n=36 n=36 n=36

n=36 n=36 n=36 n=35 n=35 n=36

n=35 n=35 n=36

<SOM in the MPW at lower transect points

<SOM in the MWs at 15-30

cm depth

C/N

ratio

: 15-

30 c

m

0.00

0.05

0.10

0.15

N (%

): 15

-30

cm

0.00

0.05

0.10

0.15

N in Upper Transect Points

NW MPW MBFW

N (%

): 0-

15 c

m

0.00

0.05

0.10

0.15

0.20

N in Lower Transect Points

NW MPW MBFW

C/N

ratio

: 0-1

5 cm

0.00

0.05

0.10

0.15

0.20

a

a

b

a

ba

a

c

b

a

c

b

n=36 n=35 n=36 n=36 n=35 n=36

n=36 n=35 n=36 n=36 n=35 n=36

N(%

): 0-

15 c

mN

(%):

15-3

0 cm

N(%

): 15

-30

cm

Soil N: Comparisons among treatments at different sample locations and depths

<N in the MPW

<N in the MWs at

15-30 cm depth

Bra

y II

P (m

g/kg

): 15

-30

cm

0

20

40

60

80

Bra

y II

P(m

g/kg

): 15

-30

cm

0

20

40

60

80

Bray II P in Upper Transect Points

NW MPW MBFW

Bra

y II

P (m

g/kg

): 0-

15 c

m

0

20

40

60

80

100

Bray II P in Lower Transect Points

NW MPW MBFW

Bra

y II

P (m

g/kg

): 0-

15 c

m

0

20

40

60

80

100

b

a

ab

b

aa

n=36 n=36 n=36 n=36 n=36 n=36

bab

a

b

a a

n=36 n=36 n=36 n=36 n=36 n=36

Soil Bray II P: Comparisons to Natural Wetlands at different sample locations and depths

>P in the MW at

Upper SP >P in MPW

~P in MBFW at lower SP

>P in the MW at Upper SP 15-30 cm

>P in MBFW at lower SP15-30 cm

GS

M (%

): 0-

10 c

m

0

5

10

15

20

25

30

Pb (above) and GSM (below) in Upper Transect Points

NW MPW MBFW

b :(g

cm-3

) : 0

-10

cm

0.50

0.75

1.00

1.25

a a a

a

ab

n=35 n=36 n=36

n=36 n=35 n=36

Pb (above) and GSM (below) in Lower Transect Points

NW MPW MBFW

b :(g

cm-3

) : 0

-10

cm

0.50

0.75

1.00

1.25

b

a

b

n=35 n=36 n=36

GS

M (%

): 0-

10 c

m

5

10

15

20

25

30

a

b

b

n=35 n=36 n=36

ρb and GSM: Comparisons among treatments at different sample locations

~ ρb in the MW at Upper SP

>ρb in MPW

<GSM in the MW at Upper SP

<GSM in MW at lower SP

ρb ρb

pH: 1

5-30

cm

5.0

5.5

6.0

6.5

7.0

7.5

8.0

pH: 1

5-30

cm

5.0

5.5

6.0

6.5

7.0

7.5

8.0

pH in Upper Transect Points

NW MPW MBFW

pH: 0

-15

cm

5.0

5.5

6.0

6.5

7.0

7.5

8.0

pH in Lower Transect Points

NW MPW MBFW

pH: 0

-15

cm

5.0

5.5

6.0

6.5

7.0

7.5

8.0

a

a

bb

a

a

n=36 n=36 n=36 n=36 n=36 n=36

aa

bb

a

a

n=36 n=36 n=36 n=36 n=36 n=36

Soil pH: Comparisons among treatments at different sample locations and depths

>pH in MW

San

d/C

lay

(%):

15-3

0 cm

0

10

20

30

40

50

San

d/C

lay

(%):

15-3

0 cm

0

10

20

30

40

50

Sand/Clay % in Upper Transect Points

NW MPW MBFW

San

d/C

lay

(%):

0-15

cm

0

10

20

30

40

Sand/Clay % in Lower Transect Points

NW MPW MBFW

San

d/C

lay

(%):

0-15

cm

0

10

20

30

40a

a

b

a

b b

b ab

a

a

b

ab

a

aa

a

ab

a

a

a

a

aa

%Sand (Black) and %Clay (Hash): Comparisons among treatments at different sample locations and depths

>Sand in the MW at Upper SP

>Sand in MPW <Clay in MPW at lower SP

>Sand in the MPW at Upper SP 15-30 cm

<Clay in MPW at lower SP15-30 cm

MPW & MBFW Soil Age (years)

20 25 30

pH

5.0

5.5

6.0

6.5

7.0

7.5

8.0

20 25 30

pH

5.0

5.5

6.0

6.5

7.0

7.5

8.0

NW MPW & MBFW Soil Age (years) NW

20 25 30

pH

5.0

5.5

6.0

6.5

7.0

7.5

8.020 25 30

pH

5.0

5.5

6.0

6.5

7.0

7.5

8.0

pH by Age in Lower Transect PointspH by Age in Upper Transect Points

p <0.0001r2 = 0.365

p <0.0001r2 = 0.326

p = 0.0004r2 = 0.164

p =0.0396r2 = 0.059

pH ↓ with soil age, especially

in surface 15 cm

Soil pH: Trends with age at different sample locations and depths

N in Upper and Lower Sample Points by Age

15 20 25 30

Upp

er N

(%):

0-15

cm

0.05

0.07

0.09

0.11

0.13

0.15MBFWNW

a

b

NW

15 20 25 30

Low

er N

(%):

0-15

cm

0.02

0.04

0.06

0.08

0.10

0.12MPWMBFWNW

a

bb

c

MPW & MBFW Soil Age (years)

Soil N: Comparisons by age at different sample

locations

<N in older soils of MBFW (upper SP)

>N in older soils of MPW (lower SP)

<N in older soils of MBFW (lower SP)

NW - Upper Sample Points NW - Lower Sample Points

Symphyotrichum lateriflorum 28.7 Symphyotrichum lateriflorum 11.17

Microstegium vimineum 19.7 Carex Frankii 6.22

Elymus virginicus 9.0 Carex sp. 5.16

Toxicodendron radicans 6.2 Lysimachia nummularia 4.85

Ranunculus hispidus 6.0 Saururus cernuus 4.21

MPW - Upper Sample Points MPW - Lower Sample Points

Phragmites australis 55.8 Cyperus strigosus 51.98

Iva annua 21.5 Eleocharis acicularis 15.04

Carex vulpinoidea 12.9 Cinna arundinacea 8.62

Eleocharis obtusa 10.4 Ammannia auriculata 6.10

Carex Frankii 4.5 Echinochloa crus-galli 2.71

MBFW - Upper Sample Points MBFW - Lower Sample Points

Carex vulpinoidea 34.3 Carex vulpinoidea 16.43

Elymus virginicus 22.4 Eleocharis obtusa 15.85

Iva annua 13.5 Typha latifolia 9.25

Persicaria virginiana 3.0 Phyla lanceolata 8.50

Carex Frankii 2.9 Iva annua 5.86

Dominant Species at each wetland type:% of total cover

Upper        

Sample Points    NW MPW MBFW

p mean ± s.e mean ± s.e mean ± s.e

Prevalence Index <0.0001 2.55 ± 54.72a 2.11 ± 49.78b 2.22 ± 0.09b

Taxa Richness <0.0001 3.25 ± 0.22a 1.97 ± 0.24b 1.86 ± 0.18b

Bare (%) <0.0001 0.08 ± 0.01a 0.01 ± 0c 0.05 ± 0.01b

Canopy Cover (%) <0.0001 93.58 ± 0.51a 2.25 ± 1.14c 54.72 ± 4.86b

Lower   

Sample Points NW MPW MBFW

p mean ± s.e mean ± s.e mean ± s.e

Prevalence Index 0.0038 2.31 ± 0.19a 1.8 ± 0.07b 1.7 ± 0.13b

Taxa Richness <0.0001 1.14 ± 0.19b 2.92 ± 0.22a 1.5 ± 0.19b

Bare (%) <0.0001 0.17 ± 0.02a 0.06 ± 0.01b 0.1 ± 0.02b

Canopy Cover (%) <0.0001 92.33 ± 0.68a 0.11 ± 0.11c 49.78 ± 4.68b

Vegetation: PI, TR, bare area, and canopy cover. Comparisons among treatment groups

<TR in MWs in upper SPs

>TR in MPWs in lower SPs

<PI (wetter plants) in MWs

< bare area in MWs

< canopy cover in MWs

• Recovery or maintenance of soil nutrient pools to levels equivalent to NWs in the surface 15 cm has occurred for SOM, C, and P in all MWs and for SOM, C, N, and P in the MBFWs

• Pools at the 15-30 cm depth are equivalent for C and P – Some C pools more recalcitrant than SOM; P high in subsoil of alfisols

• Only soil pH is changing with time past 19 years at all MWs – Soils started with existing nutrient pools or accumulation leveled off after <19 years

Conclusions: Wetland soil properties

• Based on the 5 dominant species, all three treatment groups had a unique vegetation community

• MWs appeared wetter based on the PI and data inferred from the wells and SP elevations

• TR was higher in the lower SPs in the MPWs due to the open canopy. More vegetation analysis is required to compare diversity on a landscape level

Conclusions: Hydrology and vegetation

• In Alabama (Sistani et al 1996) and Southern IL (Cole & LeFebvre 1991): equal SOM and C in mined wetland soils compared natural wetlands

• BS4N reclamation was able to use soils which had been under forest cover – Most wetland restoration occurs on soils depleted by row-crop agriculture

• Hydrology controlled by channel dimensions resulting in more regular overbank flooding

Conclusions: Are wetlands restored on mine soils different from wetlands restored on natural soils?

Management Implications: Design and soil source important for successful restoration

• Sand% was neg. correlated with every soil nutrient and organic matter stock – signaled a different soil source for the MPWs than the MBFWs

• Prolonged inundation restricted plant growth and buildup of nutrient pools at the MPWs

• Dominance by Phragmites australis occurred where conditions were supportive – reduced diversity

Questions?

• Knight Hawk coal• John Gefferth, Consol Energy• Jack Nawrot• Ron Balch, Midwest Reclamation • Funding provided by the OSM Technology

Transfer Applied Science research grant

Acknowledgements