e Impacts of Truck Traffic across Unfrozen Tundra 

= 

near Toolik Lake, Alaska 

Martha K. Raynolds, Tim Craig, and Zachary Meyers 

QH 

105 

.A4 

864 

no.121 

CHECK FOR {!fi-f< {)I"/ 

IN iae,t/Jcd:d. i 
The BLM Mission 

The Bureau of Land Management sustains the health, diversity and productivity of the public lands for the 

use and enjoyment of present and future generations. 

Cover Photo 

One of two trucks illegally driven across unfrozen tundra near Toolik Lake, Alaska in September 2006. BLM 

photograph by Boyce Bush. Other photographs in this report are by Martha Raynolds and Edith Barbour. 

Authors 

Martha Raynolds is a plant ecologist at the Institute of Arctic Biology, University of Alaska Fairbanks (UAF). 

Tim Craig is a wildlife biologist at the BLM Fairbanks District Office in Fairbanks, Alaska. Zachary Meyers 

is a UAF graduate student working at the University of Alaska Museum of the North in Fairbanks. 

Disclaimer 

The mention of trade names or commercial products in this report does not constitute endorsement or 

recommendation for use by the federal government. 

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Library & Information Services 

Anchorage Alaska 
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Impacts of Truck Traffic across Unfrozen Tundra near 

Toolik Lake, Alaska 

Martha K. Raynolds, Tim Craig, and Zachary Meyers 

SLM-Alaska Open File Report 121 

April 2010 

U. S. Department of the Interior 

Bureau of Land Management 

A,RLIS 

Alaska Resource, Library & Information Serrices 

Library Building, Suite 111 

3211 Providence Drive 

Anchorare, AK 99508•4614 
In September 2006, caribou hunters illegally drove 2 

vehicles across unfrozen tundra on land managed by the 

U.S. Bureau of Land Management in the Toolik Lake Area 

of Critical Environmental Concern on Alaska's North Slope. 

The vehicles became stuck in the tundra and were eventually 

excavated from frozen ground in April 2007. The extent of 

the impacts were evaluated in July 2007 and reevaluated in 

July 2008. The level of disturbance, as measured by categorical classes, thaw depth, and surface elevation, all increased 

significantly between years. The truck trails impacted 1457 m2 

of tundra. Habitat disturbance was quantified at 5 different 

levels with Level 1 being the least disturbed and Level 5 the 

most disturbed. In 2008 most of the trails (61 %) were Level 2 

disturbance, while 25% were Level 1, 8% were Level 3, 

3% were Level 4, and 2% were Level 5. Since the previous 

year, the trails had become deeper, more water-filled, and 

also more visually evident. The excavation sites measured approximately 75 m2 each, with 25 m2 and 36 m2 of Level 5 

disturbance at the close and far excavations, respectively. In 

contrast to 2007, areas with Level 5 disturbance were covered 

with water in 2008. Soil thaw depths were significantly deeper 

on the disturbed areas than at the control areas for most 

transects, and deeper in 2008 than 2007. Similarly, surface 

profile elevations were lower in the disturbed areas than the 

control areas, and lower in 2008 than 2007. Future monitoring 

is recommended for 2012 and 2017, 5 and 10 years from the initial disturbance. 

ACKNOWLEDGMENTS 

We acknowledge the contributions of Edith Barbour and 

Constance Zachel, who provided invaluable field assistance. 

The original manuscript benefited greatly from editorial suggestions by Craig McCaa, who also shepherded this report to 

publication. 

2.4 Vegetation Cover .......................................................... 4 

2.5 Photographs ...................................................... . ....... 5 

3. Results .................................................................... 5 

3.1 Length, Area, and Disturbance Level ......................................... . 5 

3.1.1. Truck Tracks .......................................................... 5 

3.1.2. Excavation Sites ....................................................... 6 

3.2 Transect Thaw Depth, Cover, and Elevation .................................... 6 

3.3 Point-frame Vegetation Cover ............................................... 12 

3.4 Maps and Photographs of Disturbance ........................................ 12 

4. Discussion ............................................................... . 12 

5. Summary ............ · .................................................... . 13 

6. References . .............................................................. . 14 

Appendix A. Recommendations for Future Sampling ........................... . 15 Appendix B. Cover Sampling Results by Species ............................... . 17 Appendix C. Photographs ................................................... . 21 

Table 1. Table 2. Table 3. 

Table 4. Table 5. Table 6. Table B-1. 

Table B-2. Table C-1. 

TABLES 

Tundra disturbance levels ............................................... 2 

Description, location, and length of transects established in July 2007 to 

monitor tundra disturbance ............................................. 4 

Length of trail, level of disturbance, and area disturbed by 2 pickup trucks ...... 5 

July 2007 and July 2008 measurements of area impacted and level of 

disturbance caused by excavation of trucks ........................... . .... 7 

T-test of differences between elevation profiles across trails and truck 

excavation sites ....... . .............................................. 12 

Percent cover of vegetation categories and percent decrease between vegetative cover in control sites and sites disturbed by truck trails and excavations .... 13 

Species and percent cover sampled in July 2007 on disturbed and control 

portions of transects across trails ....................................... 17 

Plant species recorded by point-frame sampling on transects across trails .. . ... 20 

Photograph points at transects in disturbed areas .......................... 21 

FIGURES 

Figure 1. Location of study sites ................................................. 1 Figure 2. Martha Raynolds mapping the footprint of the excavation at the Close 

Truck Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

Figure 3. Laser pointer used to measure el~vation along transects ..................... 4 Figure 4. Vertical point frame used to measure tundra disturbance ..................... 5 Figure 5. Area of different disturbance levels ................................... . ... 6 Figure 6. Maps of vegetation disturbance within 10-m x 10-m areas where trucks were 

excavated in April 2007 ...................................... . ......... 7 

iii 
iv 
g

(

) 

Lake Area of Critical Environmental Concern 

(ACEC). One of the vehicles, hereafter referred 

to as the "Far Truck," was a Ford F-150 with 

an estimated gross vehicle weight of 2400 kg. 

The Far Truck traveled about 4.6 km off the 

highway before it became stuck. The second 

vehicle, hereafter referred to as the "Close 

became stuck in a moist sedge, dwarf

shrub 

water track, the first non-tussock tundra 

vegetation that it encountered. The Close 

Truck, whose driver(s) mostly followed the 

Far Truck's tracks, became stuck in tussock 

tundra. 

Once the ground was completely frozen, 

attempts were made to extract the trucks in 

TOPO! map prtnted on 08/05/07 from "Untltled.tpo" 

Nj LMN v24(' 

149°2s.ooo' w 

149•2s.ooo· w 

149°22.000' w 149°19,000· w 149°16.ooo· w WGS84149°12.ooo· w 

149°22.000' W 149°19.000' w 149°16.000" W 

0.0 Oj 1.0 I j 20miles 

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o a • 5 1 o 1 5 2 o 2 5 3 o 35 km 

Mop cn,•ted with TOPOI® e2003 No.ooMI Geographic (wwwnatioMlgeogmpu: ccmAopo) 

( 

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24 

WGS84 149° 12.000" W 

Figure 1. Location of study sites along trails created by 2 pickup trucks traveling on unfrozen tundra, 

Toolik Lake ACEC, Alaska in September 2006. "Far Truck" and "Close Truck" are sites where the 

vehicles became stuck and were subsequently extracted. "Single Trail," "Double Trail," and "Worst Trail" 

are locations where transects were established perpendicular to the trail. 

BLM Open File Report 121 • April 2010 
shoveled back into the holes left in the tundra 

after the trucks were extracted. Mapping 

The BLM contracted with the University 

of Alaska to assess the initial impacts from 

that we completed the following summer (see travel on non-frozen tundra and extraction 

Methods and Results sections) showed that 

total surface disturbance from tracks and 

excavations was 1558 m2• 

of the 2 trucks and to set up procedures to 

monitor long-term impacts. Researchers from 

the University of Alaska, including one of the 

Table I. Tundra disturbance levels used to measure disturbance where habitat was disturbed by 2 

pickup trucks that traveled on unfrozen tundra in September 2006, Toolik Lake ACEC, Alaska. 

Measure 

Decrease in plant cover 

Decrease in shrub canopy 

Organic or mineral soil 

exposed 

Structural damage to 

tussocks or hummocks 

2 

Level 

0 

2 

3 

4 

5 0 

2 

3 

4 

5 

0 

1 

2 

3 

4 

5 

0 

Description 

No observable change 

0%-25% 

25%-50% 

50%-75% 

75%-95% 

>95% 

No observable change 

0%-25% 

25%-50% 

50%-75% 

75%-95% 

>95% 

None observed 

1%-5% 

5%-15% 

15%-25% 

25%-90% 

>90% 

No observable damage to slight scuffing 

1 Tussocks or hummocks scuffed 

2 Tussocks or hummocks crushed 

3 Crushed tussocks nearly continuous or ruts starting to form 

4 Continuous rut, surface vegetation mat continuously disrupted 

5 Continuous rut cut into peat soil 

BLM Open F(le Report 121 • April 2010 
We used a categorical scale to describe 

disturbance along the trails created by the 

truck tires. To determine the proportion of the 

trail in each disturbance category, we used 

a hip chain (a device that measures distance 

using a string) to measure the total distances 

along the trails as well as the distances 

between changes in the disturbance categories. Disturbance categories 0-5 ranged from 

no disturbance (0) to complete destruction (5) 

of vegetation (Table 1). Levels 1-3 were based on studies of impacts of winter seismic trails on the coastal plain of the Arctic National 

Wildlife Refuge (after Felix and Raynolds 

1989). We added 2 additional levels, 4 and 5, 

to characterize disturbance exceeding that 

caused by winter seismic vehicle traffic. 

The area of the disturbance was calculated 

using the average tire track width measured 

in 2007 (30 cm) and the length of trail showing either 2 vehicle tracks (where the 2 trucks' 

paths coincided) or 4 vehicle tracks (where 

their paths diverged). 

The distributions of disturbance levels in 

2007 and 2008 were compared using a chisquare test to evaluate the. significance of the 

changes. 

2.2 Disturbance at excavations 

At each excavation site we mapped 10-m 

x 10-m areas encompassing most of the 

disturbed ground and categorized the disturbance on the maps (Figure 2). For the most 

part we used the same disturbance categories 

as for the trails (Table 1) to calculate the 

area in each disturbance category for the 2 

excavation sites. However, in 2007 we did not 

differentiate Level 1 from Level 2 in mapping 

the excavations. 

2.3 Transects 

We established 7 linear transects in 2007 

and resurveyed them in 2008. These transects, 

30 to 50 m long, included 2 transects at each 

Figure 2. Martha Raynolds mapping the footprint 

of the excavation at the Close Truck site, 1 year 

after unauthorized trucks were driven over unfrozen tundra, Toolik Lake ACEC, Alaska, 6 July 

2007. 

excavation site (one across the middle of the 

excavation parallel to the trail, and one across 

the middle of the excavation perpendicular 

to the trail). The other 3 transects were perpendicular to the vehicle trails: one where the 

worst disturbance caused by both vehicles 

occurred, one in a location that typified the 

overall disturbance where both vehicles drove, 

and one in a location that typified the disturbance caused by a single vehicle (Table 2). 

We measured thaw depth, cover type, and 

surface elevation every meter along these 

transects in undisturbed (control) areas and 

every 0.5 min areas adjacent to and including 

vehicle tracks. We measured surface elevation from a cable held about 0.5 m above the 

ground, stretched taut between anchors at 

either end of the transect. In 2008 we also 

measured elevation on 4 transects using 

a green laser pointer mounted on a tripod 

(Figure 3). From these data we plotted the 

elevation profiles of the transects, determined 

the average thaw depth in the control and 

disturbed areas, and calculated the percentage of each cover type in the control and disturbed areas. We used t-tests to test for 

significance of differences between control and 

disturbed areas of each transect, and between 

the disturbed area of each transect in 2007 

and the same area in 2008. 

Additional information on the transects 

and sampling methodology may be found in 

Appendix A. 

BLM Open Fi!e Report 121 • April 2010 3 
Figure 3. Laser pointer used to measure elevation along transects where 2 pickup trucks created 

trails by traveling on unfrozen tundra in September 

2006, Toolik Lake ACEC, Alaska. Orange arrow 

points to green dot on.meter stick. 

in the disturbed and control portion of each of 

the 3 trail transects and at the perpendicular transect at each excavation site (Figure 4). The 

frame measured 10 points for every meter, and we recorded 10 frames for each sample. 

This resulted in 100 hits along 10 m of transect. We set up the frame along the tire tracks 

for the disturbed trail sites (perpendicular to 

the transects) and along the transects for the 

control areas and the excavation sites. We 

recorded the genus and species of each plant 

Table 2. Description, location, and length of transects established in July 2007 to monitor tundra 

disturbance caused by pickup truck travel over unfrozen tundra in September 2006, Toolik Lake ACEC, 

Alaska. 

Type of GPS Transect 

distur- coordinates length Disturbed 

Transect bance Location (WGS 84) (m) Direction portion 

Far truck excavation, 20-30 m 

Far Truck 1 Excavation perpendicular to direc- 68°41.51' N 50 East to from E end, 

tion of travel 149°19.95' w West especially 22.5-29.5 m 

Far truck excavation, 15-25 m 68°41.51' N North to from N end, Far Truck 2 Excavation parallel to direction of 149°19.95' w 40 South especially travel 16.5-24.5 m 

Close truck excavation, 68°39.52' N East to 20-27 m Close Truck 1 Excavation perpendicular to direc- 149°18.48' w 47 West from E end tion of travel 

Close truck excavation, 68°39.52' N North to 10-19 m Close Truck 2 Excavation parallel to direction of 149°18.48' w ,30 South from N end travel 

Perpendicular to trail, 

Worst Trail Level 5 trail 80 m south of close 68°39.46' N 30 East to 14-16.5 m excavation, 700 m north 149°18.41' W West from E end 

of road 

Double Trail Level 2 trail Perpendicular to trail, 68°39.33' N 40 East to 19-22 m 500 m north of road 149°18.58' w West from N end 

Perpendicular to trail, 

Single Trail Level 1 trail close to pipeline, 68°39.63' N 40 East to 18-22 m 250 m north of close 149°18.84' w West from E end 

excavation 

4 BLM Open File Report 121 • April 2010 
Each year we took photographs from both 

ends of each transect, from the edge of the disturbance looking along the transect, and from 

the center of the disturbance looking along the trail in both directions. 

3. RESULTS 

3.1 Length, area, and disturbance level 

3.1.1 Truck tracks 

The portion of the trail traveled by both 

trucks, i.e., from the Dalton Highway to the 

Close Truck excavation, was 850 m. Most of 

the disturbance along this trail was Level 2 

in both 2007 (67.3%), and 2008 (50.8%). Two 

tracks were visible over 68% of this distance, 

while 4 tracks were visible over the remaining 

32% of the distance. 

Only the Far Truck traveled the remaining 3733 m of the trail, from the Close Truck 

to the Far Truck excavation site. Because of 

its much longer length, the single-truck trail 

accounted for more of the disturbed area than 

the trail made by both trucks. Most of this trail had Level 1 disturbance in 2007 (51.6%) 

and Level 2 disturbance (62.8%) the following 

year. In contrast, most of the area with higher 

Figure 4. Vertical point frame used to measure 

tundra disturbance in the Toolik Lake ACEC, 

Alaska, 2007. The frame is 1 m long and has 10 

pins spaced at 10-cm intervals along the frame. 

disturbance levels (Levels 4 and 5) occurred 

on the trail used 

_by both trucks. 

The combined length of disturbance, including the sections traversed by both trucks and 

sections traversed by only one truck, was 

4855 m. Multiplying this length by the average 

tire track width of 30 cm resulted in a tire track disturbance of 1457 m2 (Table 3). 

In 2008 most (61 %) of the disturbance we 

detected along the tracks was Level 2, an 

increase from 40% found in 2007 (Table 3). We 

also observed an increase in areas with Levels 

3-5 disturbance, along with a commensurate 

decrease in areas with Level 1 disturbance 

(Figure 5). Overall, disturbance levels were 

significantly greater in 2008 than 2007 

(p < 0.001). 

Table 3. Length of trail, level of disturbance, and area disturbed by 2 pickup trucks that traveled on unfrozen tundra in September 2006, Toolik Lake ACEC, Alaska. Measured in July 2007 

and July 2008. 

Level of Percent of total Area disturbed Percent of total Area disturbed 

disturbance length in 2007 2007 (m2) length in 2008 2008 (m2) 

0 0.1 1 0.1 1 

1 51.6 751 25.3 369 

2 39.8 579 60.7 885 

3 6.3 92 8.2 119 

4 1.7 25 3.4 49 

5 0.6 8 2.3 33 

Total 100.0 1457 100.0 1457 

BLM Open File Report 121 • April 2010 5 
excavation activities used to extract them 

(Figure 6). The centers had a less-disturbed 

area that was protected under the middle of 

the trucks. At both sites, original vegetation 

was missing in the areas that had underlain 

the wheels; in these areas the frozen, disturbed soil and vegetation had been removed 

during excavation and later returned. At the 

Close Truck excavation, the soil was gray 

silt. At the Far Truck excavation, the soil 

was organic peat. The edges of the excavation 

areas had lower levels of disturbance caused 

by activities such as foot traffic and vehicle 

traffic on frozen tundra. 

Between 2007 and 2008, the area of the 

highest disturbance levels (Levels 3-5) 

changed little (Table 4, Figure 6). However, 

Level 1 and 2 disturbance was more evident 

and covered more area in 2008. Total disturbance of the excavation sites increased during 

this period from approximately 102 

m2 to 

152 

m2, expanding outside the 10-m x 10-m 

plots we established in 2007. As was the case 

for the truck trails, this increase in disturbed 

area was due to deeper thaw and some subsidence, which increased water cover (Figure 7) and decreased plant cover. In 2008 water 

covered 0%-25% of the Level 3 disturbance, 

50%-75% of the Level 4 disturbance, and 

100% of the Level 5 disturbance. 

3.2 Transect thaw depth, cover, and elevation 

Thaw depths in disturbed areas were significantly deeper than in control areas at all but 

the worst trail, where 2 trucks had traveled 

(Figure 8). Thaw depths were deeper in 2008 

than in 2007 (35-60 cm compared to 25-45 

0 

3500 

3000 

_2500 

IN 

.§.2000 

ca 

1500 

c( 

1000 

500 

0 1 2 3 4 

Disturbance level 

• One truck • Two trucks 

5 

0 L----.1.....11---'--

0 2 3 4 5 

Disturbance level 

Figure 5. Area of different disturbance levels 

caused when 2 pickup trucks traveled on unfrozen 

tundra in September 2006, Toolik Lake ACEC, 

Alaska. Top - all trails evaluated in July 2007 

and 2008. Bottom - trails caused by a single truck 

compared to trails caused by 2 trucks, evaluated in 

July 2008. Differences in distributions are significant (chi-square test, p<0.001). 

cm). We observed little change between years 

in the amount of vegetative cover on portions of 

the transects crossing trails compared to adjacent control areas (Figure 9). The excavation 

sites, on the other hand, had less live vegetation and more soil and water cover than control 

areas. Elevations were significantly lower in 

the disturbed areas than in the control areas 

for most transects (Figure 10). Elevations of 

the disturbed section were lower in 2008 than 

in 2007 for all 4 excavation transects. 

6 SLM Open File Report 121 • April 2010 

--" 

--' 

.e 

..e 

.e 

• 
1---1 

1 meter 

Far Truck 2007 

' Far Truck 2008 ' 

1 

-

meter 

Disturbance level 

- - - - Transects ••~~- • * oilsheen 0 1 2 3 4 5 

Figure 6. Maps of vegetation disturbance within 10-m x 10-m areas where 

trucks were excavated in April.2007 after becoming stuck in unfrozen tundra in September 2006, Toolik Lake ACEC, Alaska. Central portions of the transects crossing the excavations are depicted by dashed lines. Mapping was completed in July 2007 and July 2008. 

Table 4. July 2007 and July 2008 measurements of area impacted and level of 

disturbance caused by excavation of trucks that had become stuck after traveling 

on unfrozen tundra in September 2006, Toolik Lake ACEC, Alaska. Disturbance outside the 10-m x 10-m plots established at each site is not included in the table. 

Close Truck Close Truck Far Truck Far Truck 

Disturbance Excavation Excavation Excavation Excavation 

level 2007 (m2) 2008 (m2) 2007 (m2) 2008 (m2) 

0 52.8 13.6 45.7 34.3 

1 34.1 7.8 2.0 9.1 2 13.4 10.8 

3 7.3 5.8 4.5 7.6 

4 8.9 7.6 2.7 3.7 

5 29.0 25.4 38.0 35.8 

BLM Open File Report 121 • April 2010 7 
Figure 7. Photos taken in 2007 and 2008 at the Close Truck (left) and Far Truck (right) excavation sites, 

where habitat was disturbed by 2 pickup trucks that traveled on unfrozen tundra in September 2006, 

Toolik Lake ACEC, Alaska. All photos were taken from the southern edge of the excavations looking 

north, matching the orientation of the maps in Figure 6. 

8 

80 

70 

E 60 

-------7 

*** * i - I I I 

u 

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Q. 

-* 

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Worst Double Single 

Trail Trail Trail 

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L 

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I 

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i 

--·--------------------------~ 

Figure 8. July 2007 and July 2008 thaw depths measured along 

7 transects where habitat was disturbed by 2 pickup trucks that 

traveled on unfrozen tundra in September 2006, Toolik Lake ACEC, 

Alaska. One transect was perpendicular (perp.) and one parallel (par.) 

to the direction of travel at the Far Truck and Close Truck excavation 

sites, and 3 transects were perpendicular to trails where different 

disturbance levels occurred (Worst Trail, Double Trail, Single Trail). 

T-test significance of difference between disturbed and control in each 

year: * = p < 0.05, ** = p < 0.01, *** = p < 0.001. 

BLM Open File Report 121 • April 2010 

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Far par. Close perp. Close par. Worst Trail Double Single Trail 

Trail 

IJ Water 

• Bare 

• Dead • Live 

July 

2008 

[] Waler 

• Bare 

• Dead • Live 

Figure 9. Percent cover of live vegetation, dead vegetation, bare soil or peat, and water 

measured in July 2007 and July 2008 on control and disturbed sections of 7 transects where 

habitat was disturbed by 2 pickup trucks that traveled on unfrozen tundra in September 

2006, Toolik Lake ACEC, Alaska. One transect was perpendicular (perp'.) and one parallel 

(par.) to the direction of travel at the Far Truck and Close Truck excavation sites, and 3 

transects were perpendicular to trails where different disturbance levels occurred (Worst 

Trail, Double Trail, Single Trail). 

BLM Open File Report 121 • April 2010 9 
..... 

0 

I 

70 80 

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e 60 I 60 

I \ . ~ 

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Figure 10. Elevation profiles of transects established across trails and truck excavation sites resulting from unauthorized truck travel over 

unfrozen tundra in September 2006, Toolik Lake ACEC, Alaska. Data were collected in July 2007 and July 2008. Transects: a) perpendicular 

to the Far Truck excavation, b) parallel to the Far Truck excavation, c) perpendicular to the Close Truck excavation, d) parallel to the Close 

Truck excavation, e) perpendicular to Worst Trail (Disturbance Level 5), f) perpendicular to the Double Trail (Disturbance Level 2), g) perpendicular to the Single Trail (Disturbance Level 1). The disturbed area is in the middle of each transect, shown with gray shading. See Table 5 

fort-test analysis of differences. 

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Worst trail n.s. .... 

Double trail · n.s. ** 

Single trail *** * 

3.3 Point-frame vegetation cover 

Cover of live vegetation measured in 2007 

by point-frame sampling was less in all disturbed areas than control areas (Table 6) and 

was >90% less in the excavation areas. Cover 

of live vegetation in the trails was 87% less in 

the Worst Trail and 28% and 34% less in the 

Double and Single trails, respectively. Reduction of nonvascular cover (mosses and lichens) 

was generally more than reduction in vascular 

cover. However, this was difficult to measure 

in this first summer after disturbance, as 

many of the mosses and lichens were broken 

and detached. Although these plants appeared 

to be alive in 2007, some may die in subsequent years. Species-level data are presented 

in Appendix B. 

3.4 Maps and photographs of disturbance 

Photographs of the transects are included 

in the compact disc attached to this report and 

are listed in Appendix C. Example photos of 

the 3 trail sites are sho~n in F1gure 11. We 

established a set of standard photo points to 

ensure that photographs are taken from the 

same sites and with the same field of view 

each year. 

by laser) by cable) by laser} 

*** *** *** 

*** * n.s. 

** ** *** 

NA ** NA NA * NA 

NA n.s. NA 

*** . n.s. n.s. 

4. DISCUSSION 

We calculated the area impacted by the 

trucks by adding the area of the excavation 

sites to the product of the length of the 

discernible disturbance along trails and the 

width of the tire tracks. In subsequent years, 

as subsidence occurs, the impacted area will 

likely increase (Felix et al. 1992). The types 

of impacts will also change with time. Initial 

impacts included destruction of vegetation 

along with some change in surface elevation 

due to the excavations and the tire tracks. 

Based on studies of similar disturbance in the 

Arctic National Wildlife Refuge, subsidence is 

likely to occur in and adjacent to areas with 

disturbance greater than Level 2, causing 

increases in soil moisture and changes in 

plant species composition (Felix et al. 1992, 

Emers et al. 1995). Revegetation of bare areas 

will occur, but in many cases, revegetated 

areas will exhibit a different species composition than the original vegetation. The Arctic 

National Wildlife Refuge studies also indicated 

that decreased cover values, changes in thaw 

depth, surface elevation, and species composition are likely to persist for longer than 10 

years (Emers et al. 1995). Even the Tucker 

12 BLM Open File Report 121 • April 2010 
positive feedback: the sun warms the water, 

which in turn thaws the permafrost, causing 

a reduction in soil ice that leads to further 

subsidence and even more surface water ponding. As a result, the disturbance level of the 

trails increased between 2007 and 2008, and the trails, because of their significantly deeper thaw depths, were significantly lower than the surrounding tundra. The size of the area 

monitoring should include 5-year and 10-year 

resampling of the sites (2012 and 201 7). 

5. SUMMARY 

Two vehicles driven across non-frozen tundra in September 2006 affected over 1607 m2 of 

tundra. We quantified the habitat disturbance 

at 5 different levels, with Level 1 being the 

Table 6. Percent cover of vegetation categories and percent decrease between 

vegetative cover in control sites and sites disturbed by truck trails and excavations resulting from unauthorized truck travel across unfrozen tundra in Toolik Lake 

ACEC, Alaska, September 2006. Measured by point-frame sampling in July 2007. 

% Cover 

Disturbance %Cover %Cover Decrease in 

type Cover Control Disturbed Disturbed 

Live vegetation 118 10 92 

Far Truck Vascular 62 7 89 excavation 

Moss perpendicular 56 3 95 

Lichen 0 0 none 

Live vegetation 102 3 97 

Close Truck Vascular 51 3 94 excavation 

Moss perpendicular 37 0 100 

Lichen 14 0 100 

Live vegetation 116 15 87 

Vascular 37 11 70 Worst Trail 

Moss 74 4 95 

Lichen 5 0 100 

Live vegetation 128 92 28 

Vascular 60 42 30 Double Trail 

Moss 62 47 24 

Lichen 6 3 50 

Live vegetation 141 93 34 

Vascular 67 46 31 

Single Trail Moss 71 39 45 

More lichen in 

Lichen 3 8 disturbed than 

control 

SLM Open File Report 121 • April 2010 13 
addition, thaw depths were generally deeper 

in disturbed areas than control areas, and 

Figure 11. Photos of trails caused by pickup truck 

travel on unfrozen tundra in September 2006, 

Toolik Lake ACEC, Alaska. Top - Worst Trail, 

looking south. Middle - Double Trail, looking 

south. Bottom - Single Trail, looking south. 

disturbance. In 2008 the greater thaw depths 

in both the control and disturbed areas and 

the lower elevations in disturbed areas (especially the excavations) resulted in pooling of 

surface water at excavation sites. The types 

of impacts and area impacted are likely to change over the next 10 years, and continued 

monitoring is recommended. 

6. REFERENCES 

Emers, M., Jorgenson, J.C., and Raynolds, 

M.K. 1995. Response of arctic tundra 

plant communities to winter vehicle disturbance. Canadian Journal of Botany 

73(6):905-917. 

Felix, N. A., and Raynolds, M.K. 1989. The 

effects of winter seismic vehicle trails 

on tundra vegetation in northeastern 

Alaska, U.S.A. Arctic and Alpine Research 

21(2):188-202. 

Felix, N. A., Raynolds, M.K., Jorgenson, J.C., 

and DuBois, K.E. 1992. Resistance and 

resilience of tundra plant communities to 

disturbance by winter seismic vehicles. 

Arctic and Alpine Research 24(1):69-77. 

14 SLM Open File Report 121 • April 2010 
ated to determine whether the proportion in each disturbance level changes (1 person-day). 

The vegetation point-frame sampling would 

take an additional 2 person-days of field time, 

for a total of 6 person-days each year. In 2017 

a long-term resampling schedule should be 

determined. 

For questions, contact Martha Raynolds 

(MarthaRaynolds@alaska.edu), 907-47 4-6720. 

A.1 Repeating trail disturbance measures 

Measuring the proportions of the trails 

with 2 or 4 tracks need not be repeated. This 

distinction will only become less visible and 

more difficult to determine with time. The 

proportions measured in 2007 can be used 

for all subsequent calculations. Similarly, 

the length of the track measured in 2007 can 

be used for all subsequent calculations. The 

disturbance rating along the trail should be 

repeated to document recovery by determining 

the percentage of the trail in each disturbance 

category. A hip chain is useful, but well-calibrated paces can also be used, as the goal is to obtain a percentage of the total trail length. 

Bring a copy of the disturbance rating sheet 

on water-resistant paper and refer to it often 

to maintain consistency of ratings. 

A.2 Updating the maps 

Make copies of the 2008 maps or use a clear 

overlay to map changes. Using pin flags and 

a tape to mark the outline of the 10-m x 10-m 

square and center lines is very helpful. Mapping at the excavation sites will likely need 

to be expanded in future years to include all 

of the areas disturbed by subsidence. Use the 

same 5 disturbance level categories as for the 

trails. 

A.3 Repeating the transect measurements 

We permanently marked the ends of the 

transects with pieces of rebar 0. 75 m long 

num tags with identification information at 

ground level. The locations where transects 

crossed the trails were recorded from a 

Garmin eTrex® GPS in degrees decimal 

minutes using WGS 84 (Table 2 in the report). 

Print the forms that are specific to each 

site (name and sampling locations are already 

filled in). Bring new aluminum tags to replace 

missing or illegible ones. Upon arrival at the 

site, make sure the ends of the transects are 

still well marked. The rebar may have jacked 

out and need to be pounded in again. 

The laser technique we used for measuring 

transect elevations in 2008 was much quicker 

to set up and measure than the cable technique. The laser dot, visible even on sunny 

days, expanded in diameter to only about 1 cm 

at 25 m and did not enlarge much beyond that 

distance. However, the laser's greatest benefit 

was that it eliminated the error introduced 

by the cable's sag across long transects. Cable 

sag makes the center of the transect seem 

higher than it really is relative to elevations 

taken at the ends of the cable, particularly 

for transects longer than 40 m. As a result, 

the graphs for the 50-m transects parallel to the truck excavations exhibit higher values 

for the cable transects than for the laser 

transects in the transects' centers, where the 

excavations are located (Figure 10 a, c). Comparisons between years for cable data are still 

valid because cable sag is probably consistent 

between years. Nonetheless, future comparisons could be improved by using just the laser 

technique. 

One unresolved problem with the laser 

is that it cannot be used in rainy weather 

because it might short-circuit. This could be 

remedied by placing a shelter over the instrument. 

Another modification that would improve 

the year-to-year consistency of the elevation 

data would be to place small pin-flags at each 

measuring point. Even a few centimeters of 

BLM Open File Report 121 • April 2010 15 
laser for measuring elevation and thaw depth, 

rather than the much more elaborate cable 

system, which is subject to inaccuracies due to 

cable sag. 

A.4 Repeat point framing 

Bring the data sheet that shows the sections of the transect that were sampled with 

the point frame in 2007 and repeat the pointframe sampling in the same locations. Use a 

small level to ensure that the frame is more 

or less level vertically and horizontally. It can 

also be useful to bring the species list from 

previous years, as the same species will likely 

be hit in subsequent years. Collect samples of 

any unknown species you hit and bring them 

back to Toolik Field Station for identification. 

The Toolik herbarium has good collections of 

non-vascular and vascular plants. 

A.5 Repeat photographs 

Bring the data sheet that shows the photo 

point numbers and locations. Three types 

of photographs have been taken during this 

project. Landscape photographs are taken by 

including a small amount of sky in the top 

of the photograph. Photos of the disturbance 

are taken from either edge of the disturbance, 

framed so as to include just the disturbed 

area. Vertical photos are taken looking 

straight down. It is very easy to confuse which 

photo is which, so take them in a consistent 

order (preferably the order on the data sheet), 

and write down the photo numbers as you 

take them. Take additional photos of the 

general site and of people sampling. 

1 meter stick 1 green laser pointer 

1 tripod with rotating, adjustable top 

Small umbrella or other shelter for laser 

1 50-m tape 

Thaw probe (1-m long) 

Digital camera 

GPS 

Pencils 

Markers (including one that will write on 

overlays for making changes to excavation 

maps) 

Clipboard 

1 copy of disturbance rating descriptions 

on water-resistant paper 

2 trail disturbance data sheets on waterresistant pa per 2 copies of maps of excavations on waterresistant paper 

7 transect elevation, thaw and cover data 

sheets on water-resistant paper 

10 point-frame data sheets 1 photo point data sheet (3 pages long) on 

water-resistant paper 

Point frame (vertical frame: 1-m long with 

10 pins and 2 legs - borrowed from Arctic 

National Wildlife Refuge, contact Janet 

Jorgenson or Dave Payer) 

Small level (for point frame) 

Duct tape (at least 20 cm for restraining 

point frame pins) 

Rubber bands (to stop point frame from 

sliding down point frame legs) 

16 BLM Open File Report 121 • April 2010 
Close Truck Control BETNAN 5 AULTUR 9 CETCUC 3 Litter 43 

CARBIG 2 DICRA 12 CETISL 2 CASTET 4 HYLSPL 4 CLAGRA 3 

ERIVAG 16 SPHAG 12 CLARAN 4 

LEDDEC 13 DACARC 2 

RUBCHA 3 

VACVIT B 

Disturbed BETNAN 1 Litter 3 

ERIVAG 2 Water 1 

Bare soil/ 96 

peat 

Far Truck 

Control BETNAN 5 SPHAG 53 Litter 70 

CARROT ;g leafy liver- 3 

wort 

ERIANG 1 

SALFUS 37 

Disturbed CARROT 2 SANUNC 2 Litter 5 

ERIANG 1 SPHAG 1 Bare soil/ 92 

peat 

RUBCHA 2 

SALFUS 2 

Worst Trail 

Control ANDPOL 1 AULTUR 7 CLAGRA 1 Litter 30 

BETNAN 4 DICRA 8 CLARAN 4 

ERIANG 1 HYLSPL 3 

ERIVAG 6 POLJUN 13 

LEDDEC 5 SPHAG 43 

PEDLAB 1 RUBCHA 6 

SALARC 1 

VACVIT 12 

(cont.) 

SLM Open File Report 121 • April 2010 17 
RUBCHA 1 

VACVIT 2 

Double Trail 

Control BETNAN 11 AULTUR 6 CETCUC 1 Litter 43 

CARBJG 1 DICRA 6 CLARAN 1 

CASTET 1 HYLSPL 12 DACARC 4 

ERIVAG 8 SPHAG 37 

LEDDEC 13 6 

POLBIS 1 leafy liver- 1 

wort 

RUBCHA 1 

SALPUL 1 

VACVIT 23 

Disturbed ANDPOL 1 AULTUR 6 CETCUC 2 Litter 51 

BETNAN 11 DICRA 11 PELMAL 1 Pear 1 

CARBIG 1 HYLSPL 10 

CASTET 1 POLJUN 2 

ERIVAG 13 SPHAG 18 

LEDDEC 4 

RUBCHA 2 

VACVIT 9 

Single Trail 

Control ANDPOL 1 AULTUR 6 CETISL 1 Litter 39 

BETNAN 13 DICRA 5 CLARAN 2 

CARBIG 3 HYLSPL 5 CASTET 1 POLJUN 2 

ERIVAG 10 SPHAG 53 

LEDDEC 16 

PEDLAB 2 RUBCHA 8 

SALPUL 2 

VACVIT 11 

(cont.) 

18 BLM Open File Report 121 • April 2010 
ERIVAG 4 SPHAG 22 DACARC 2 

LEDDEC 8 PELMAL 1 

RUBCHA 4 

SALPUL 3 

VACVIT 12 

SLM Open File Report 121 • April 2010 19 
20 

ANDPOL Andromeda polifolia 

BETNAN Betula nana 

CARBIG Carex bigelowii CARROT Carex rotundata CASTET Cassiope tetragona 

ERIANG Eriophorum angustifolium ERIVAG Eriophorum vaginatum 

LEDDEC Ledum palustre ssp. decumbens 

PEDLAB Pedicularis labradorica 

POLBIS Polygonum bistorta RUBCHA Rubus chamaemorus 

SALARC Salix arctica 

SALFUS Salix fuscescens 

SALPUL Salix pulchra 

VACVIT Vaccinium vitis-idaea 

Mosses 

AULTUR Aulacomnium turgidum 

DICRA Dicranum sp. 

HYLSPL Hylocomium splendens 

POLJUN Polytrichum juniperinum* 

SANUNC Sanionia uncinata SPHAG Sphagnum sp. 

Lichens 

CETCUC F/avocetraria cucullata CETISL Cetraria islandica 

CLAGRA C/adonia gracilis CLARAN Cladina rangiferina* 

DACARC Dactylina arctica PELMAL Peltigera malacea* 

* tentative species identification 

BLM Open File Report 121 • April 2010 
Transect 1 - East end, looking W Landscape view 1-1 

Perpendicular to Close 20 m from E end, looking W Landscape view 1-2 Truck excavation 20 m from E end, looking W Just disturbance 1-3 

23.5 m from E end, looking down Vertical 1-4 27 m from E end, looking E Just disturbance 1-5 27 m from E end, looking E Landscape view 1-6 

West end, looking East Landscape view 1-7 

Transect 2- North end, looking S Landscape view 2-1 

Parallel to Close Truck 11 m from N end, looking S Landscape view 2-2 

excavation 11 m from N end, looking S Just disturbance 2-3 

15 m from N end, looking down Vertical 2-4 

19 m from N end, looking N Just disturbance 2-5 

19 m from N end, looking N Landscape view 2-6 

South end, looking N Landscape view 2-7 

Transect 3 - East end, looking West Landscape view 3-1 

Perpendicular to Worst 14 m from E end, looking W Landscape view 3-2 

Trail (Disturbance 14 m from E end, looking W Just disturbance 3-3 Level5) 

14 m from E end, looking down Vertical 3-4 15 m from E end, looking N Landscape view 3-5 

15 m from E end, looking S Landscape view 3-6 15.8 m from E end, looking down Vertical 3-7 

16 m from E end, looking E Just disturbance 3-8 

16 m from E end, looking E Landscape view 3-9 

West end, looking East Landscape view 3-10 

Transect 4- East end, looking West Landscape view 4-1 

Perpendicular to Far 22 m from E end, looking W Landscape view 4-2 

Truck excavation 22 m from E end, looking W Just disturbance 4-3 

22 m from E end, looking down Vertical 4-4 

30 m from E end, looking E Just disturbance 4-5 30 m from E end, looking E Landscape view 4-6 

West end, looking East Landscape view 4-7 

(cont.) 

BLM Open File Report 121 • April 2010 21 
25 m from N end, looking N Just disturbance 5

5 

25 m from N end, looking N Landscape view 5-6 

South end, looking N Landscape view 5-7 

Transect 6- East end, looking West Landscape view 6-1 

Perpendicular to 18 m from E end, looking W Landscape view 6-2 Double Trail 18 m from E end, looking W Just disturbance 6-3 (Disturbance Level 2) 

18 m from E end, looking down Vertical 6-4 

20 m from E end, looking N Landscape view 6-5 

20 m from E end, looking S Landscape view 6-6 22 m from E end, looking down Vertical 6-7 

22 m from E end, looking E Just disturbance 6-8 22 m from E end, looking E Landscape view 6-9 

West end, looking East Landscape view 6-10 

Transect 7- East end, looking West Landscape view 4-1 

Perpendicular to East end, looking West Landscape view 7-1 Single Trail 18 m from E end, looking W Landscape view 7-2 (Disturbance Level 1} 

18 m from E end, looking W Just disturbance 7-3 

18 m from E end, looking W Vertical 7-4 

20 m from E end, looking N Landscape view 7-5 20 m from E end, looking S Landscape view 7-6 

22 m from E end, looking E Vertical 7-7 22 m from E end, looking E Just disturbance 7-B 

22 m from E end, looking E Landscape view 7-9 

West end, looking East Landscape view 7-10 

22 BLM Open File Report 121 • April 2010 
ARLIS 

Alaska Resources 

Library & Information Services 

Anchorage Alaska 

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