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BLM-Alaska Open File Report 82

BLM/AK/ST-01 /00 1 +92 1 7+020

September 2000

Recovery of Lichen in

Tussock Tundra Following Fire in

Northwestern Alaska

Randi R. Jandt and C Randy Meyers

JK

870

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06

no. 82

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Cover Photo

Caribou bull from study sites on the Seward Peninsula in 1997 (photo Aaron Jokisch)

Disclaimer

The mention of trade names or commercial products in this report does not constitute endorsement or recommendation for use by the federal government

Authors

Randi Jandt is a fire ecologist, Bureau of Land Management (BLM), Alaska Fire Service, 1541

Gaffney Road, Ft. Wainwright, Alaska 99703; and Randy Meyers is a botanist/natural resource

specialist BL M's Northern feild Office PO Box 1049 Kotzebue Alaska 99752 At the time of the

study, Randi Jandt was wildlife biologist for the BLM Northern Field Office in Fairbanks, Alaska

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Recovery of Lichen in

Tussock Tundra Following Fire

in Northwestern Alaska

Randi R. Jandt and C. Randy Meyers ^

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BL M Alaska Open File Report 82

September 2000

U. S. Department of the Interior Bureau of Land Management

Contents

Abstract iii Acknowledgments iii Introduction 1 Study Area 1 Methods 3 Results 4

Post-fire Succession at Ulukluk Creek 4

Lichen Recovery on Older Burn Sites 6

Discussion and Management Implications 6

Lichen Recovery 6

Recovery of Vascular Plants '. 7

Comparison of Point-frame and Canopy Cover Class Methods 9

Conclusion 9

Literature Cited 11 Appendix A: Tundra fire recovery at Ulukluk Creek study sites 13 Appendix B: Transect one (Tl) and Transect two (T2) at post-burn intervals 14 Appendix C: Three-year photoplot comparison 16

Appendix D: Successional changes on individual quadrats at post-burn intervals. Ulukluk Creek study site 18

Appendix E: Comparison of individual unburned control quadrats at the Ulukluk Creek study site 20

Appendix F: Tundra fire recovery in western Alaska 21

Figures

Figure 1. Map location and plot layout 2

Figure 2. Plant cover over time on burn and control transects. Buckland Valley 5

Tables

Table 1. Results of point-intercept sampling comparison of Ulukluk Creek transects 4

Table 2. Changes in vegetative canopy cover over time 5 Table 3. Comparison of burn severity index (BSI) and percent lichen cover 6

Table 4. Comparison of paired control and burned transects at two sites 20-25 years after fire 8

Abstract

Paired permanent vegetative cover transects were established after a small (2 ha) 1981 tundra fire in the Buckland River valley of western Alaska. Data on the regeneration of forage lichens was collected 14 years

after the burn and compared to conditions in adjacent unburned plots. Graminoids, primarily cottongrass

(Eriophorum vaginatum), were stimulated by the fire and grew still more vigorously on the burn area (55%

cover in burn vs. 44% in adjacent unburned area). Lichen cover on burned plots had recovered very little (1%)

compared to unburned plots (15%). Further study is required to establish a regeneration curve, but data from

older bums in tussock tundra in western Alaska indicate the recovery period for fire-disturbed ranges of the Western Arctic Caribou Herd ( WACH) is well over 25 years. Recovery times appear similar to those reported

for the Northwest Territories of Canada. Land and wildlife managers need information on lichen regeneration

timelines specific to their regions to establish sound fire management guidelines for caribou (Rangifer

tarandus) winter range. Point-intercept sampling, compared to canopy cover estimation, proved to be a more

efficient sampling technique in the tundra cover type.

Acknowledgments

This study was supported by the BLM Northern Field Office in Fairbanks. Alaska. Several investigators were involved in background research, study design, and/or data collection, including Layne

Adams (Research Biologist. USGS Biological Research Division. Anchorage. Alaska). Bruce

Connery (Natural Resource Specialist. Acadia National Park. Maine). Melanie Miller (Fire Ecologist,

BLM Fire and Aviation Policy Office in Boise. Idaho): and Keith Woodworth (Natural Resource

Specialist) and Michelle Corrigan (Biotechnician). both of BLM-Alaska's Northern Field Office.

Fairbanks, Alaska.

in

INTRODUCTION

North American caribou {Rangifer tarandus)

herds are largely dependent on lichens for winter

forage. Prevalence of ground lichens in the winter diet has been estimated to be as high as 80-95% in Canada (Beverly and Qamanirjuaq

Caribou Management Board. 1 994). Winter fecal

pellets from caribou in the Buckland Valley

consisted of 85% lichens in 17 composite

samples (Jandt. unpublished data) indicating that lichen constitutes a major portion of the winter

diet for the Western Arctic Caribou Herd, which

winters in this area. Studies have shown that caribou will select for this high carbohydrate

food when available, with lichens of the Cladina, Cladonia and Cetraria genera most

frequently mentioned. Preference trials on

reindeer in Finland suggested the following

"'reindeer lichens" in order of decreasing palatability: (Cladina rangiferina > C. stellaris > C. mitis ) > Cladonia uncialis > Cetraria islandica > Cetraria nivalis > Alectoria spp. >

Stereocaulon spp. (Norberg et al. 1995).

A review of the literature for lichen reestablishment times found substantial differences

reported from various geographic areas. Black

and Bliss (1978) described black spruce stands

in the lower Mackenzie Valley in Canada's

Northwest Territories, where Cladina mitis first became important 120-200 years postfire. Stands

dominated by lush growths of caribou-preferred

lichen species such as Cladina stellaris (previously called Cladonia alpestris), Cladina

rangiferina and Cetraria cucullata were fre- quently over 200 years old. In contrast, other

locations in the Northwest Territories reported

stands that had 38% cover of caribou lichens by

44 years and 65% cover by 92 years (Rowe et al. 1974). Differences in reestablishment times

should be expected, as the time required depends on climate, fire severity, moisture regimes, soil types, etc. Based on surveys of four taiga stands

in northcentral Canada, Scotter (1970) stated

that it takes about 100 years for lichens to reach

their former abundance after fire. Other investi- gators have reported shorter intervals for re- establishment (Miller 1976. Bergerud 1974.

Pegau 1975).

Land managers need estimates of succession

timelines for their specific regions so management plans for wildlife habitat and fire can be

scientifically based. After review of existing

knowledge of the ecological relationships of

caribou, lichens and fire. Klein (1982:394)

concludes: "'Long-term monitoring of the responses of range vegetation to fires of differ- ing intensities clearly should be a high priority

of government agencies responsible for management of caribou range lands." This priority is reiterated in the BLM's Buckland Valley Habitat

Management Plan (1983). which covers much of

the winter range of the Western Arctic Caribou

Herd. Data on the reestablishment times required

by caribou forage lichens on tussock tundra

communities that characterize the core winter

range for the Western Arctic Caribou Herd are generally lacking in the scientific literature. On

the herd's eastern ranges in the upper Kobuk

Valley. Swanson (1996) found that C. stellaris and C. rangiferina increased almost five-fold on

dry terraces and uplands older than 100 years compared to 10- to 50-year-old stands. In contrast. C. mitis and Cladonia spp. reached

peak abundance in the 50- to 100-year-old

stands. STUDY AREA

On 25 July 1981, a lightning-ignited fire burned approximately 2 ha of low shrubcottongrass (Eriophorum vaginatum) tussock

tundra on Ulukluk Creek. 5 km south of the Buckland River (Fig. 1). The Buckland Valley is a broad plain spanning about 100 km between

the Selawik Hills to the north and Talik Ridge to the south. Forested river valleys of the Kateel

and Huslia rivers to the east are clearly differentiated from the predominantly treeless tundra of

the Buckland valley. Treeless tundra continues to dominate the landscape on the Seward Peninsula

west of the main study area. Mean biomass of

live lichen in this region was estimated by

Adams and Connery (1983) at 161 ± 22 g/m2

, and vascular production at 64 ± 5 g/m2

, Vegetation

at the Ulukluk Creek study site was mapped and

described by Swanson et al, (1985) as low

shrub-cottongrass tussock tundra. Cottongrass, a

classic example of the tussock growth form,

forms large, compact tussocks 15-40 cm tall throughout arctic landscapes of Alaska and

Canada (Hulten 1968. Porsild and Cody 1980).

It was the dominant graminoid at our study sites. Transects at two older burn sites (Wagon
Figure 1. Map location and plot layout of Ulukluk Creek study site, northwestern Alaska.
Wheel and Pargon River) farther west on the Seward Peninsula were placed in lichen tussock

tundra. Low shrub-cottongrass tundra is an

ecological site characterized by high cover

values for shrubs (25-50%) and graminoids (25-

50%), with moderately low amounts of lichen

(6- 12%), and small values for forb cover (0-6%).

In contrast, the lichen tussock tundra ecological

site typically has high cover values for lichens

and shrubs (both 25-50%). with moderate

graminoid cover (12-25%), and moderately low

forb cover (6-12%) (Swanson et al. 1985). Plant nomenclature follows Hulten ( 1968) for vascular

plants and Thomson (1972) for lichens.

The Buckland Valley comprises an integral

part of the winter range of the Western Arctic

Caribou Herd—currently the largest caribou

herd in the state and one of Alaska's major

wildlife resources. A 1993 photocensus esti- mated a minimum herd size of 450,000 caribou

(Machida and Dau 1995). The herd ranges over

about 360.000 km2 of tundra and taiga habitat in northwest Alaska and calves mainly on the North Slope between the Lisburne Hills and the Colville River. The herd has been increasing in size, although more slowly in recent years, after a drastic decline between 1970 and 1976 when it dropped from 240.000 to 70.000 animals (Davis

and Valkenburg 1978). The decline was thought

to be caused largely by excessive human harvest, although predation, disease and possibly

range conditions were also implicated.

Wildfires occur in the Buckland Valley and

surrounding highlands, but they are not as frequent as in the spruce forests of interior Alaska. Over 90% of fires are caused by light

ning and very large fires (>200.000 ha) occur

about every 10 years. The BLM is responsible

for fire management in most of this area. The

current management policy is to monitor fires, natural or human-caused, rather than suppress

fires unless they present a threat to human life or

property. The BLM's current fire management

goal is to achieve a natural fire regime.

METHODS

Two sets of permanent transects were established on 29 July 1981 to monitor recovery and

succession of vegetation in the burn. Paired

transects were located along the east and west

flanks of the burn, one inside and one outside

the burn perimeter (Fig. 1). Each 50 m transect was marked with reinforcing rod stakes and

twenty-five 20 by 50 cm quadrats were spaced

evenly along the transects. Transects 1A and IB

run 330°along the eastern flank while Transects

2A and 2B run 320° along the western perimeter.

The severity of the burn at each transect was

quantified by estimating the portion of each

quadrat that corresponded to five fire severity

classes used by Viereck et al. ( 1979): unburned.

scorched, lightly burned, moderately burned and

severely burned. Coverage within each burn

severity class was estimated to the nearest 5%.

Within quadrats, plant cover by species and by cover type (shrub, forb. lichen) was estimated

within six percentage categories: 0-5%, 6-25%<,

26-50%. 51-75%, 76-95% and > 95%

(Daubenmire 1959). Cover values were recorded

as the mean of the cover class (i.e. 2.5. 1 5, 37.5,

etc.) for analysis. A Shannon diversity index was

calculated for pooled burned and unburned

transects (Ludwig and Reynolds 1988). Richness was estimated as the total number of species

present anywhere along the transect. Photos were taken vertically over a 20 by 50 cm sampling frame every 5 m along each transect. Plots were surveyed during late summer in 198 1

.

1982. 1983. 1984 and 1995. Due to staff turn- over, transects were surveyed by a different

observer pair after 1984.

After completing the Daubenmire sampling in 1995. sampling on each transect was repeated

using a point-sampling frame, with 50 string

intersections over a 0.5 nr area (frame size: 1 m

x 0.5 m). The height was adjustable depending on the vegetation, from 0.25 to 0.5 m. The first plant species encountered directly under an

intersection was recorded as a hit. For this method 12 quadrats were located every 4 m

along the transect, starting at m. Cover values were calculated as the number of hits on one

species or cover class divided by the total number of points in a quadrat (n=50). Mean

cover value was the average of all quadrats

within the transect. Only the canopy cover based on first hits is reported in this paper. The number of transects was small: four for Ulukluk Creek and two at Wagon Wheel and Paragon River. For areas with one transect in each treatment type, statistical inference for means and standard error is necessarily limited to the transect, whereas for
Ulukluk Creek statistical inference is for the treatment areas, based on two samples of each.

Thus, for Wagon Wheel and Pargon River, mean

cover values for the transect based on quadrats

are reported and for Ulukluk Creek mean cover

(from both transects) of a given treatment and its associated standard error (

v frr) are reported.

RESULTS

Post-fire Succession at Ulukluk Creek

Although visual contrast between the old burn

in treeless tundra and the surrounding area was

subtle, the fire boundary could still be detected

from aerial reconnaissance. The burn appeared

darker than surrounding vegetation,

partly due to the absence of lichen cover and

partly to the vigorous cottongrass revegetation.

Closer inspection on the ground revealed some

less-obvious differences, including dead standing Labrador tea (Ledum palustre ssp. decumbens) shrubs and fire-damaged tussocks.

On the burned transects, lichens had not recov- ered and the <1% lichen cover that was recorded on point-intercept transects (Table 1 ) consisted

primarily of Cladonia spp. squamules. which

were difficult to positively identify. Scattered

tiny tufts of Cladina mitis/arbuscula, C. rangiferina and Cetraria cucullata were present

in trace amounts. Graminoids. especially

cottongrass. increased rapidly at Ulukluk Creek

after the fire. Average cover of cottongrass rose from < 1% in 1981 to >30% in 1984. while

unburned plots averaged 13-20% during this period (Table 2). Even 14 years after the burn,

percent graminoid cover in the burned plots was

still higher than any previous year surveyed

(Fig. 2). and cottongrass cover values were 11%

greater than the unburned plots (Table 1). Dwarf

shrubs increased steadily over time on burned

plots at Ulukluk Creek (Fig. 2). Burned plots

averaged 3 1 % shrub cover by 1 995. while

TREATMENT

COVER TYPE Unburned SE(N=2) Burned SE(N=2) Difference

Carex spp. 9.3 1.3 8.8 0.9 -0.6 Eriophorum spp. 34.5 12.2 45.9 7.4 + 11.4 Total Graminoid: 43.8 10.8 54.7 6.5 + 10.8 Rubus chamaemorus 2.3 0.3 2.0 0.5 -0.3 Other forb 0.2 — 0.1 — -0.1 Total Forb: 2.5 0.2 2.1 0.4 -0.4 Ledum palustre 11.2 7.5 15.2 5.8 +4.1

Vaccinium uliginosum 5.8 1.3 7.2 3.3 + 1.5 Betula nana 2.2 0.8 3.2 1.2 +0.9

Empetrum nigrum 2.9 0.6 0.9 0.8 -2.0 Other shrub 6.3 — 4.8 — -1.5 Total Shrub: 28.4 7.6 31.4 4.1 +3.0

Cladonia rangiferina 5.0 0.3 0.1 0.1 -4.9* Cladina mitis/arbuscula ' 2.5 1.2 0.1 0.1 -2.4 Cetraria cucullata 6.1 2.4 0.2 0.3 -5.8 C islandica 1.1 0.1 0.1 0.1 -1.0* Other lichen 0.8 — 0.8 — 0.0

Total Lichen: 15.4 4.4 1.2 0.4 -14.2*

'Significance as determined by Student's t-test. small sample inference for n=2 transects/treatment.

p<0.05 .

'Species of lichens that cannot be distinguished without chemical tests.

Table 1. Results of point-intercept sampling comparison of Ulukluk Creek control and bum transects 14 years

after fire in a lichen tussock tundra habitat, northwestern Alaska. Reported values are relative cover on the transects expressed as a percent.
1981 19H2 1983 19X4 1995

Burn/Control Burn/Control Burn/Control Burn/Control Burn/Control

Lichen 0.5 28.4 1.2 39.9 0.9 38.2 0.0 35.0 3.2 27.2

Moss 7.8 12.8 7.0 7.7 4.9 10.2 1.1 9.9 2.6 6.0

Grass/Sedge 0.3 12.6 16.4 15.6 27.4 20.0 34.1 18.0 53.9 40.2

Forb 0.0 5.4 2.8 5.3 3.0 4.2 4.0 5.2 3.5 3.6 Shrub 0.0 28.0 10.0 33.2 13.4 39.4 19.0 48.4 30.4 35.7

Litter 0.0 16.0 56.2 7.2 71.8 18.4 60.6 16.0 9.7 7.8 Species Richness 8 20 15 20 13 18 9 16 17 23

Diversity (IT) 1.49 1.96

Table 2. Changes in vegetative canopy cover over time in a tussock tundra community burned in July 1981 (one week preceding the first sampling) expressed in per cent. Within quadrats, plant cover was estimated

within six percentage categories and midpoints used to generate means (Daubenmire 1959)

unburned plots averaged 28% (Table 1). However, crowberry (Empetrum nigrum) appeared to be recovering much more slowly than other

shrubs. The average percent cover of crowberry

on unburned plots over all the study years was

5.7% (Daubenmire plots), but the average in burned transects in 1981 was 0.0% and by 1995

it had only increased to 0.2%.

Lichen cover in control plots should have

varied little between 1981 and 1995. but could

have been subjected to grazing by caribou or disturbance by trampling. Signs of recent caribou utilization within transects were not noted during surveys. Measured lichen cover (27.2%) using the quadrat cover class method in 1995 was similar to the 1981 estimate of 28.4%>

50

~. 40

a.§

o

o

S 30

20

10

Control Avg.

^

rii

Cottongrass Graminoids Blueberry Forbs Shrubs Reindeer"

lichens

Figure 2. Plant cover over time on bum and control transects. Buckland Valley, Alaska percent cover based on

quadrat cover class estimates (Table 1

)
on control transects, indicating that data col- lected by two observer pairs from different

years was reasonably comparable (Table 2). The

overall composition of control plots was similar

to results obtained in 1981. except for an

increase in graminoid cover, primarily

cottongrass, which increased by about three-fold

(Fig. 2. Table 2). Species richness was reduced by half initially,

and in 1995 was still lower in the burned (17

species) transects v.v. control (23 species)

transects. The mean Shannon diversity index was determined using point transect data. There was less diversity in the 14-year-old burned

transects (H' = 1.49) than the unburned controls

(H' = 1.96). Species found in the control plots

that were not recorded in burn plots tended to be

plants of small stature and low frequency such

as Cladonia uncialis, Thamnolia spp.. Oxycoccus microcarpus, and Andromeda

pglifolia. These tiny plants could easily escape

detection if present in trace quantity.

Both Ulukluk Creek transects were light-tomoderately burned and the overall BSI (burn

severity index) was equivalent for both transects (Table 3). The fact that Transect 1 had more area

that was just scorched (34%) than Transect 2

(18% scorched or unburned) may be related to the slightly greater lichen cover percentage

observed in Transect 1 in 1982 ( 1 .7% vs. 0.8%)

and also to the greater lichen cover in 1995

(Table 3). However, these differences were not

significant, and when plots were studied indi- vidually to compare burn severity and lichen cover in 1982 to the lichen cover in 1995, no

clear pattern is apparent.

Lichen Recovery on Older Burn Sites

Other Buckland Valley sites that burned in 1970 and 1972 shared many characteristics of

the Ulukluk Creek study, including low percentage of lichen cover, remnants of dead Labrador

tea. foliose lichens in wet intertussock spaces, and early stages of most fruticose lichens still less than 1 cm in length. All Buckland Valley

sites could have been subject to grazing or disturbance by caribou from the Western Arcrtic

Herd, which increased steadily during the recovery period. To see whether the observed

recovery times in the Buckland Valley were

retarded by repeated caribou disturbance, paired

transects were established in 1997 on two older

burn sites from a Seward Peninsula region that has received very little grazing pressure by

caribou or reindeer during the last 50 years. Both

sites were also located in lichen tussock tundra

and were similar to the Ulukluk site, except that lichens had been relatively undisturbed at these

sites since the fires. At Wagon Wheel, which

burned in 1977, the percent lichen cover was 4.3 ± 0.7 compared to 49.3 ± 1 .3 on the unburned

control (Table 4). In the aftermath of a 25-yearold fire on the Pargon River ( 1972), lichen cover was 3.2 ± 0.4% compared to 40.0 ±1.1% for the unburned control (Table 4). Lichen recovery

measured as percent of the unburned control was

therefore similar at the 20-year-old burn (8.7%)

and the 25-year-old burn (8.0%).

DISCUSSION AND

MANAGEMENT IMPLICATIONS

Lichen Recovery

Burn sites from 14 to 25 years old were still in the initial stages of lichen reestablishment.

Lichen cover had increased less than 3% in 14

years following fire (Table 2, Fig. 2). and was

still < 5% after 25 years (Table 4). This slow

pace of recovery is consistent with patterns for lichen recovery in boreal coniferous forest

% % % % % Lichen Lichen

Area Scorched Lightly Moderately Severely BSI Cover (%) Cover (%)

Transect Unburned Burned Burned Burned 1982 1995

Burned #1 34 43 22 3 2 5 Burned #2 4 15 75 6 3 1 2

Table 3. Comparison of bum severity index (BSI) and percent lichen cover by quadrat cover class after one

year and 14 years at Ulukluk Creek fire recovery study site, Alaska.
reported by Ahti (1977). Ahti found that reindeer lichens such as Cladina mitis, C. arbuscula, C. rangiferina and Cladonia

uncialis did not become dominant until 50- 120 years after fire and noted that moisture

regime and climate were important factors affecting time spent in various successional

stages.

Lichens establish by a variety of sexual

and asexual propagules. Many fruticose

lichen taxa including Cladonia, Cladina,

Bryoria and Ramalina are highly adapted to propagate by thallus fragments (Dibben

1971, Nash 1996). Reestablishment of

reindeer lichens such as Cladina spp. may

occur by slow reinvasion of wind-blown

fragments (Johnson 1981. Moreau and

Payette 1989). Many types of lichen

propagules are carried substantial distances

when melt water flows across arctic tundra

in the spring. Dispersal of lichen propagules

by wind blowing over smooth snow in winter is believed to be particularly signifi- cant in local dispersal (Thompson 1972). A

small burn, included within a larger un- burned tussock tundra habitat providing a

local source of lichen propugules. should

present the best conditions for early reestab- lishment of lichen. Although these conditions were present at Ulukluk Creek, we

found reestablishment to be in the very

early stages.

Even after establishment, growth of

individual Cladina lichens is slow. Growth

rates for Cladina rangiferina have been

measured at 5 to 6 mm per year on the Seward Peninsula of Alaska (Pegau 1968:

and Meyers, unpublished data). However,

over time and in the absence of major

disturbance such as fire, heavy grazing or

severe trampling, lichens on arctic rangelands can compete favorably with vascular

plants. Production data gathered for lichen

tussock tundra on the Seward Peninsula

estimated live lichen biomass at 111.5 g/m: (995 lb/ac) and an average annual vascular

plant production of 63.3 g/m2 (565 lbs/ac:

Swanson et al. 1985).

Fire alters the competitive relationship

between lichens and vascular plants on

arctic rangelands. On shallow, cold and

nutrient-poor arctic soils underlain by

permafrost and topped by an insulating mat of

organic material, lichens exist in a reasonably

competitive status with vascular plants. Lichens can

utilize nutrients stored in the organic mat, whereas

vascular plants grow better in mineral soil (Ahti and

Hepburn 1967. Topham 1977. Lawrey 1984.

Swanson et al. 1985). Many fruticose lichens are

lightly entangled within the live vegetative surface

layer and are readily killed by fire (Longton 1988).

In contrast, many vascular plant species have roots and meristems more deeply buried in moist vegetative mats or mineral soil and are better able to withstand a tundra fire (Wein and Bliss 1973). Fire

reduces or eliminates the organic mat. decreases

surface albedo, promotes thaw of mineral soil and

enhances availability of mineral nutrients. All of

these actions directly benefit vascular plants (Viereck

and Schandelmeir 1980. MacLean et al. 1983).

Recovery of Vascular Plants

A common finding by Racine ( 1 98 1 ). Wein and

Bliss ( 1973) and current study was the rapid postfire recovery of graminoids. especially cottongrass.

All studies cited vigorous basal sprouting and

significantly increased density of flowering shoots one to two years after fire. Cottongrass cover values in the burned transects exceeded those in the unburned transects by 11%

after 14 years (Table 1), and 19% after 20 years and

20% after 25 years (Table 4). Physiological studies

(Chapin et al. 1979) have shown that the tussock

growth habit of E. vaginatum creates a favorable

microclimate that becomes snow-free sooner, with a longer growing season than between-tussock areas. Soil temperature within the tussock is raised, enhancing nutrient cycling and root growth. Chapin and

associates suggest the link between the high productivity and widespread distribution of cottongrass may

be a result of the tussock growth form. The competitive advantage of the tussock growth form, plus an

initial pattern of warmer soils and improved plant

nutrient status as demonstrated by Wein and Bliss

( 1973) for dominant plant community species may

explain the continued dominance of cottongrass in burned tussock tundra sites over time. Carex spp. did

not follow this pattern and generally had the same or lower cover values in burned plots compared to unburned plots (Table 1, Table 4). We cannot account for the three-fold increase of

graminoid cover on unburned control tran-sects in Ulukluk Creek in 1995 (40%) compared to 1984
Wagon Wheel 1977 Burn Pargon River 1972 Burn

Cover Type Unburned SE Burned SE Diff. Unburned SE Burned SE Diff. Carex spp. 5.5 1.5 1.5 0.9 -4.0 7.2 1.9 7.7 1.5 +0.5

Eriophorum spp. 13.3 3.0 32.7 3.7 + 19.3 10.5 2.1 30.0 3.2 + 19.5 Other graminoid 0.0 — 0.0 — 0.0 0.0 — 0.2 — +0.2

Total Graminoid: 18.8 2.9 34.2 3.8 + 15.3 17.7 2.7 37.8 2.9 +20.2

Rubus chamaemorus 1.2 0.5 4.8 1.2 +3.7 1.8 0.5 4.0 1.1 +2.2

Other forb 1.2 — 0.0 — -1.2 0.0 — 0.0 — 0.0

Total Forb: 2.3 0.7 4.8 1.2 +2.5 1.8 0.5 4.0 1.1 +2.2

Ledum palustre 3.8 0.8 23.0 2.6 + 19.2 6.0 0.7 9.0 1.9 +3.0

Vaccinium uliginosum 5.0 l.l 5.3 1.8 +0.3 13.7 1.4 15.3 3.6 + 1.7 Betula nana 1.8 0.6 2.7 1.3 +0.8 1.8 0.7 1.3 0.9 -0.5 Empetrum nigrum 2.5 1.0 0.0 0.0 -2.5 2.3 1.6 0.0 0.0 -2.3

Other shrub 2.2 — 3.8 — + 1.7 9.0 — 13.0 — +4.7

Total Shrub: 15.3 1.6 34.8 2.8 + 19.5 32.3 2.3 38.8 2.6 +6.5

Cladonia rangiferina 25.3 2.4 0.7 0.4 -24.7 15.2 1.8 0.5 0.4 -14.7

C. mitis/arbuscula 8.8 1.4 0.8 0.4 -8.0 17.0 2.6 1.5 0.7 -15.5

Cetraria cucullata 7.2 1.6 0.0 0.0 -7.2 1.0 0.4 0.0 0.0 -1.0

C. islandica 4.5 0.8 0.0 0.0 -4.5 5.0 0.8 0.2 0.2 -4.8

Other lichen 3.5 — 2.8 — -0.7 2 — 1.0 — -1.0

Total Lichen: 49.3 4.4 4.3 2.3 -45.0 40.0 3.8 3.2 1.2 -36.8

Table 4. Comparison of paired control and burned transects at two sites 20-25 years after fire in a lichen tussock tundra habitat, northwestern Alaska (results in percent canopy cover based on point-intercept

sampling).

(18%) (Table 2). If the original investigators

counted only the basal area of tussock-forming

graminoid species, whereas we estimated the canopy cover, this might have caused the

disparity. However, we cannot rule out a real increase in graminoid cover on the control plots,

due to seed saturation from the nearby burn,

effects of caribou disturbance, or other environmental factors. Graminoid cover is consistently

greater on the burned plots from the third season

post-burn.

Dwarf shrubs increased steadily over time on

burned plots (Fig. 2) and shrub cover had

recovered to approximate pre-bum levels after 14 years (Table 2). The trend in shrub cover

increase on burned plots is still evident after 20

and 25 years. Cover values for shrubs appeared

to peak after 20 years on Wagon Wheel burned

plots. 35% compared to 15% on the unburned.

By 25 years following fire. Pargon River burned

plots showed 39% shrub cover, with 32% shrub cover in unburned plots (Table 1 ). Dwarf shrub

recovery at all three transect sites was largely

due to a positive cover increase by Labrador tea (Table 1 . Table 4). Of the four most common

shrub species present, only crowberry failed to recover at least 70% of its former cover values

14 years after fire. At Ulukluk Creek 14 years

post-fire, crowberry cover was 0.9% compared

to 2.9% cover in the unburned transects (Table

1 ). At Wagon Wheel and Pargon River, crowberry was not documented in the burned plots,

although it did contribute low cover values of

2.5% and 2.3% in the unburned transects (Table

4). This differential recovery may be related to the depth or location of underground stems and
roots that are the sites of resprouting after fire. Dwarf shrubs that grow deeply into the organic

mat or tussock mass might incur less fire damage and re-establish more quickly than those near the surface. Crowberry has shallow roots and a complex of horizontal stems thinly buried

in the organic mat. resulting in a below-ground

biomass located near the surface (Shaver and

Cutler 1979). In contrast. Labrador tea had roots

at intermediate depths (Shaver and Cutler 1979).

Racine ( 198 1 ) found no crowberry in sedge

tussock-shrub tundra on the Seward Peninsula

two years after fire, while other dwarf shrubs,

such as Labrador tea, lowbush cranberry

(Vaccinium vitis-idaea) and blueberry (V. uliginosum), did show small increases in cover and stem density two years after fire. Our study classified cloudberry (Rubus

chamaemorus) as herbaceous, following Hulten

( 1968) and Porsild and Cody (1980). although

this species is also recognized as a creeping

shrub (Racine 1981. Shaver and Cutler 1979)

due to its semi-woody stem base. Forbs in general comprised a small cover component (2-

6%) on all transects. Cloudberry had essentially

returned to prefire cover values after 14 years

(Table 1 ). and was two to four times higher in the burned transects 20 and 25 years after fire (Table 4).

Comparison of Point-frame and

Canopy Cover Class Methods

class estimation and 1.2% by point-intercept,

while on unburned control transects we measured 27.2% and 15.4% respectively (Table 2. Table 1 ). Floyd and Anderson ( 1987) found that quadrat class estimation overestimated small

understory plants and rare species, due to the assumption that cover values are uniformly

distributed about the mid-points of the cover

classes: that is. a trace of lichen would be

counted as 2.5%. This appears to be the case for lichens in the present study, and we believe the point-intercept estimates to be better estimates

of these classes and more repeatable among

different observers. As previously mentioned,

we believe an unexplained increase in graminoid

cover on unburned control plots may be due to sampling technique by different observers using

the quadrat cover class method. Since the pointintercept sampling also yielded the most conservative difference between lichen cover in burned

and unburned transects, we have reported the point-intercept findings in Table 1 and used

them as the basis for our conclusions.

Estimates of cover were based on first hits at the point of interception, without attempting to sample successive layers of vegetation. This can

create problems when the vegetation of interest

is low-growing and covered by taller plants,

such as lichen growing under a dwarf shrub

overstory. For future sampling, we plan to use

all successive species encountered in the sighting line for estimating cover.

Sampling time required for the point-intercept

technique was approximately 50% of time

required for the quadrat cover class (Daubenmire) method. Although half as many quadrats were deployed per transect with point-interception, the area actually sampled was 6 m2 compared to 2.5 nr. Generally, a larger plot area reduces between-plot variance, improving the confidence of estimates.

Cover values from each of the major species

appeared similar with each method, although the point-intercept method yielded slightly lower

means. The average difference between percent cover values obtained with quadrat cover class method and those obtained with point-intercept was less than 4%. The greatest difference

between the two methods was in the estimation

of lichen cover. Average lichen cover over burned transects was 3.2% by quadrat cover

CONCLUSION

Tussock tundra forms the core of the Western

Arctic Caribou Herd's winter range and is an

important component of the herd's summer

range as well. This study and other investigations of tussock tundra recovery after fire in Alaska and Canada (Racine 1981. Wein and

Bliss 1973) demonstrate the resilience of tus- sock-forming graminoids and shrubs, and the vulnerability of lichens and mosses to wildfire.

Fourteen years is early in terms of reported

lichen succession, and at Ulukluk Creek both

crustose and fruticose lichen species were just

barely measurable in terms of cover. If the measured rate of increase is extrapolated linearly

to 50 years, lichen cover would still be about

7%, substantially less than the control cover of

15% and probably not enough to be valuable
winter forage for caribou. Instead, percent lichen cover at this site is expected to increase along a non-linear curve, most likely approaching a sigmoid growth pattern over 100-200 years. Canadian observers reported significant in- creases in reindeer lichen biomass between stand

age classes of 21-40 years and 41-60 years, and

significant increases in indices of caribou use from age class 41-60 to 61-80 years (Thomas et

al. 1996). Scotter ( 1967) previously concluded

that caribou made little use of stands younger

than 50 years in upland lichen forests of subarctic Canada. On the Porcupine caribou herd's

winter range in Yukon Territory. Russell et al. (1993) noted that biomass of Cladonia spp. peaked between 51-125 years while that of

Cetraria spp. increased with age of the stand. Amounts of reindeer lichen at our burn study

sites aged 14-25 years were all below thresholds

considered useful as caribou forage. Because re- establishment times vary so dramatically in different geographic locations, it is very important to continue monitoring the Buckland Valley

study site at 5-year intervals so the recovery

time for this site can be accurately estimated.

Other variables that may affect lichen re- establishment following fire include burn

severity, precipitation, grazing pressure, trampling, fire return and soil type (Swanson et al. 1985).

Long-term monitoring of the Ulukluk Creek

study site and other fire locations should be

continued to obtain data for estimating timelines.

The point-intercept sighting frame is an efficient and repeatable way to conduct future measurements. This study illustrates a need for an

inventory of the present caribou winter range

and its status relative to past fire occurrence.

Fire management goals that reflect the present

size and needs of the caribou herd and its users should be established, based on knowledge of

ecosystem components and how much old- growth lichen range is available for caribou.

The area used by caribou for winter range

should be managed for long fire-return intervals,

with the interval determined by the recovery

time of preferred forage species in this locality.

At times it will be prudent to suppress wildfires

in specific portions of the range, such as when

the threat of very large fires is great and the supply of alternative winter range is limited.

Since knowledge of the relative importance of

different habitats used by caribou throughout the year is limited, habitat use and availability

studies are needed to document the importance

of different seasonal habitats used by caribou

and the role fire plays in these ecosystems.

Although it seems clear that fire has a short-term

detrimental effect on caribou winter ranges, the

long-term effects (>50-70 years) must also be

considered. Lichen declines in productivity and

quality in very old stands (>200 years) and it has

been reported that low-intensity fires stimulate

regrowth (Klein 1982). In lichen woodlands near Abitau Lake, Northwest Territories, forest canopies began to close about 130 years postfire, with moss starting to replace the lichen

component (Maikawa and Kershaw 1976). Thus,

fire may play an important role in maintaining

caribou winter range, especially near treeline.

10
LITERATURE CITED

Adams. L.G. and B.A. Connery. 1983. Buckland

River reindeer/caribou conflict study final report. USDI BLM Open File Report 8. Fairbanks. Alaska.

Ahti. T. 1977. Lichens of the boreal coniferous

zone. In: Seaward. M.R.D.. (ed.) Lichen

ecology. N. Y.: Academic Press. 145-181.

Ahti, T. and R.L. Hepburn. 1967. Preliminary

studies of woodland caribou range, especially on lichen stands in Ontario. Ontario

Dept. of Lands and Forests. Resource

Branch Resource Report ( Wildl.) No. 74. Ottawa. Ontario.

Bergeruder. A.T. 1974. Decline of caribou in North America following settlement. J. Wildl. Manage. 38(4):757-770.

Beverly and Qamanirjuaq Caribou Management

Board. 1994. Fire management on the forested range of the Beverly and

Qamanirjuaq caribou herds: a technical

report. The Secretariat. Ottawa. Ontario.

Black. R.A. and R.C. Bliss. 1978. Recovery

sequence of Picea mariana- Vaccinium

uliginosum forests after burning near

Inuvik. Northwest Territories. Canada Can.

J. Botany 56:2020-2030.

BLM. 1983. Buckland Valley master habitat

management plan. USDI BLM. Fairbanks.

Alaska. 59pp.

Chapin. F.S.. K. Van Cleve and M.C. Chapin.

1979. Soil temperature and nutrient cycling

in the tussock growth form of Eriophorum

vaginatwn. J. of Ecology 67: 169-189.

Daubenmire. R.F. 1959. A canopy coverage

method of vegetation analysis. Northwest

Science 33:43-64.

Davis. J.S. and P. Valkenburg. 1978. Western

arctic caribou herd studies. Alaska Dept. of

Fish and Game P-R Reptorts W- 17-8-R and

W-17-9-R. Juneau. Alaska.

Dibben. M.J. 1971. Whole-lichen culture in a phytotron. Lichenologist 5:1-10.

Floyd. D.A. and J.E. Anderson. 1987. A comparison of three methods for estimating

plant cover. J. of Ecology 75:221-228.

Hulten, E. 1968. Flora of Alaska and neighboring territories. Stanford Univ. Press,

Stanford. Conn.

Johnson. E.A. 1981. Vegetation organization and

dynamics of lichen woodland communities

in the Northwest Territories. Canada.

Ecology 62(l):200-2 15. Klein. D.R. 1982. Fire, lichens, and caribou. J Range Manage. 35:390-395.

Lawrey. J.D. 1984. Biology of lichenized fungi

Praeger Press. N.Y. Longton. R.E. 1988. Biology of polar bryophytes and lichens. Cambridge Univ. Press, N.Y. Ludwig. J. A. and J.F. Reynolds. 1988. Statistical ecology. Wiley-Interscience. N.Y. Machida, S. and J. Dau. 1995. Caribou. ///: M. V

Hicks (ed.) Annual report of surveyinventory activities. Alaska Dept. of Fish

and Game. Fed. Aid in Wildl. Restoration

Project W-24-2 and 24-3. Study 3.0. Juneau, Alaska.

MacLean. D.A.: S.J. Woodle and M.G. Weber.

1983. Fire and nutrient cycling, p. 1 1-132.

///. Wein. R.W.. and D.A. MacLean (eds.)

The role of fire in northern circumpolar

ecosystems. John Wiley and Sons, Ltd. Chichester, England.

Maikawa. E. and K.A. Kershaw. 1976. Studies on lichen-dominated systems: XIX: the

postfire recovery sequence of black sprucelichen woodland in the Abitau Lake region.

Northwest Territories. Can. J. of Botany

54:2679-2689.

Miller. D.R. 1976. Wildfire and caribou on the

taiga ecosystem of north-central Canada

PhD Thesis. Univ. of Idaho. Moscow,

Idaho.

Moreau. C. and S. Payette. 1989. Post-fire

lichen-spruce woodland recovery at the

limit of boreal forest in northern Quebec

Can. J. of Botany 67:2770-2782.

Nash. T.H. (ed.) 1996. Lichen biology. Cambridge Univ. Press. N.Y. Norberg. H.: V Maijala. and M. Nienimen.

1995. Forage preference of semi-domestic

reindeer in northern Finland. Poster presentation at Second Int. Arctic Ungulate Conf.

held Aug. 13-17, 1995 (Fairbanks, Alaska).

Pegau. R.E. 1968. Growth rates of important

reindeer forage lichens on the Seward

Peninsula, Alaska. Arctic 21:255-259.

i

I
Pegau. R.E. 1975. Analysis of the Nelchina

caribou range, p. 316-323 hi: Luick. J.R.; P.C. Lent. D.R. Klein and R.G. White,

(eds.) Proc. of First Int. Reindeer and

Caribou Symposium, Aug. 9-11. 1972

(Fairbanks, Alaska). Biol. Papers of the

Univ. of Alaska. Fairbanks. Alaska.

Porsild, A.E. and W.J. Cody. 1980. Vascular

plants of continental Northwest

Territories. Canada. Nat. Museums of

Canada. Ottawa. Ontario.

Racine. C.H. 1981. Tundra fire effects on soils and three plant communities along a hill- slope gradient in the Seward Peninsula.

Alaska. Arctic (34):7 1-84. Rowe. J.S.: J.L. Bergsteinsson, FA. Padbury and

R. Hermesh. 1974. Fire studies in the Mackenzie Valley. Indian and Natur. Affairs

Canada Pub. QS-1567-000-EE-A1. Ottawa.

Ontario. Canada.

Russell. D.E.; A.M. Martell and W.A.C. Nixon.

1993. Range ecology of the Porcupine

caribou herd in Canada. Rangifer Spec.

Issue 8. Scotter. G.W. 1967. Effects of fire on barrenground caribou and their forest habitat in northern Canada. Trans. North Amer. Wildl.

Conf. 32:243-254.

Scotter. G.W. 1970. Wildfires in relation to the

habitat of barren-ground caribou in the

taiga of northern Canada: Proc. Tall Timbers Fire Ecol. Conf. (Tallahassee, Florida).

10:85-106.

Shaver, G.R. and J.C. Cutler. 1979. The vertical distribution of live vascular phytomass in cottongrass tussock tundra. Arctic and

Alpine Res. 11:335-342.

Swanson, D.K. 1996. Fruticose lichen distribution in the Kobuk Preserve Unit. Gates of

the Arctic National Park. USDI NPS Tech.

Rept. AFA RNR/NRTR-96/28. Anchorage.

Alaska.

Swanson. J.D.: M. Schuman and P.C. Scorup.

1985. Range survey of the Seward Peninsula reindeer ranges. Alaska. USDA Soil

Conserv. Service. Anchorage, Alaska.

Thomas, D.C.; S.J. Barry and G. Alaie. 1996.

Fire-caribou-winter range relationships in northern Canada. Rangifer 16(2):57-67.

Thomson, J.W. 1972. Distribution patterns of

American arctic lichens. Can J. Botany

50:1135-1156.

Thomson, J.W. 1984. American arctic lichens: 1. The macrolichens. Columbia Univ. Press. N.Y. Topham. P.B. 1977. Colonization, growth.

succession and competition, p. 3 1 -68.

In: Seaward. M.R.D. (ed.) Lichen ecology.

Academic Press. N.Y.

Viereck. L.A.; M.J. Foote, C.T. Dyrness. K. Van

Cleve. D. Kane and R. Siefert. 1979.

Preliminary results of experimental fires in the black spruce type of interior Alaska.

USDA Forest Service Resource Note PNW332. Portland. Ore. Viereck, L.A. and L.A. Schandelmeier. 1980.

Effects of fire in Alaska and adjacent

Canada - a literature review. USDI BLM.

Tech. Rept. 6. Anchorage. Alaska.

Wein. R.W. and L.C. Bliss. 1973. Changes in arctic Eriophorum tussock communities

following fire. Ecology 54(4):845-852.

12
Appendix A: Tundra fire recovery at Ulukluk Creek study site

A-l. General aerial view of 2 ha bum scar in 1983. two years post-burn

A-2. Aerial view of the burn scar in 1995. Although more difficult to discern, the burn appears slightly darker than surrounding vegetation,

probably due to lack of light-colored lichen. The point of origin is still clearly visible as a dark spot (wet depression) at the top of the photo.

13
Appendix B: Transect one (Tl) and transect two (T2) at one month, one

year, and 14 years post-burn

B-l. Tl -Burned. July 1981. from origin.

B-2. Tl -Burned, July 1982. from origin.

B-3. Tl -Burned, August 1995, from origin.

14
Appendix B (continued)

r _^_ Jti^a ^A

B-4 Tl -Control. July 1981. from origin.

B-5. T 1 -Control. July 1 982. from origin.

B-6. Tl -Control, August 1995, from origin.

15
Appendix B (continued)

B-7 T2-Burned. July 1981, from origin.

B-8. T2-Bumed, July 1982, from origin.

B-9. T2-Bumed, August 1995, from origin. 16
Appendix B (continued)

B-10. T2-Control, July 1981. from origin

B-ll. T2-Control, July 1982, from ongin

B-12. T2-Control, August 1995, from origin 17
Appendix C: Three-year photoplot comparison.

Plots located at the burn edge and marked with metal stakes. Following are two of six

photoplots studied.

C-l. Photoplot 2A.

7 August 1981.

C-2. Photoplot 2A,

17 July 1982.

C-3. Photoplot 2A,

4 July 1983.

18
Appendix C (continued)

^K"j" ^,o^—- , ,:-^m

C-4. Photoplot 1A,

7 August 1981.

1A

-

C-5. Photoplot 1A,

17 July 1982.

mtm^mr^M

C-6. Photoplot 1A, 4 July 1983.

19
Appendix D: Successional changes on individual quadrats at one

month, two years, and 14 years following fire at the Ulukluk Creek

study site.

D-l. Burned T2-20m.

1981

D-2. Burned T2-20m,

1983

D-3. Burned T2-20m,

1995

~",^f#^ , 7, Wl

J V ,• 55*3

20
Appendix D (continued)

D-4. Burned T2-40m,

1981

v *W&&' sir?* *^"*kS

<*:£& ft?;

5" ^*&vv!

D-5. Burned T2-40m,

1983

~

•?*&£a-^ : .•*&'

.* » -liKr

£2m ..*^"$5&-.ii«

D-6. Burned T2-40m.

1995

21
Appendix E: Comparison of individual unburned control quadrats at the

Ulukluk Creek study site from 1983-1995. Little change is evident.

1983 1995

Tl Control-20m E-4.T1 Control-20m

Jf r ; ^

'-

^ ,' ,..'V '

Tl Control-30m E-5. Tl Control-30m

Tl Control-40m E-6.T1 ControMOm

22
Appendix F: Tundra fire recovery in western Alaska.

»— . &

F-l. A vigorous cottongrass

bloom marks the Ulukluk

Creek bum area in 1983

F-2. Close-up of flowering

cottongrass at the Ulukluk

Creek bum in 1983, the second season following

fire.

f#

n&> —

JL —|

<*•*:«•?< mJ:&

,-' | .if

-

.1

F-3. Early lichen regeneration on

fire-damaged tussock in the Ulukluk Creek burn site, 1995.

23
Appendix F (continued)

F-4. Dead Labrador tea (Ledum

paIustre) branches were a finding common to tundra burn sites aged 14-25 years. (Ulukluk Creek study site, 1995)

F-5. Large, vigorous tussocks of cottongrass were a

finding common to tundra bum sites aged 14-25

years. (Ulukluk Creek

study site, 1995)

1

V

•>

'~'4T', A?'

(h-i »

' >

•

/

F-6. A fire-damaged tussock from

a 1972 fire in the Buckland

Valley demonstrating early

regeneration of lichens 24

years after fire. Early growth

forms of lichen (squamules)

are difficult to identify to species (Fire #8719, 1996) *'

• e*«

* r>

*

'•

**»»-^

*a

24
Appendix F (continued)

.sSl. '. f

r. ; .i

F-7. Investigators using pointsampling frame with 50

string-intersection grid to estimate vegetative cover

at bum and control sites. (R.R. Jandt and

C.R. Meyers 1996)

25
A.

A ,i .-> . ^ > ^
1 Q

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u z ^

^ | $5 8

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to O x:

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D|

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