Leave No Trace
Outdoor Skills and Ethics
The Science behind the Practices
T1 T2
I1
T3
I2
T4
I3
Soil Loss
T5 T6
I4 I5
Presentation Objectives
 Describe recreation ecology research and how it
helps inform the development of Leave No Trace
practices.
 Highlight some of the
more relevant research
findings for each Leave
No Trace principle.
The LNT Message
LNT practices are science-based:
Recreation ecology research tells us about recreation
impacts and the relative influence of use-related,
environmental, and managerial factors. This information
helps us to develop effective Leave No Trace practices.
The LNT Message
Social science research tells us about visitor attitudes,
behaviors, social norms, and effective methods of
communicating low impact practices.
Haleakala National Park
(Simulation - proliferation of informal trails)
Informal (Visitor-Created)
Trail Impacts
Impact
Indicators
Park Zones
Developed
(11.7 ha)
Threshold
(16.2 ha)
Natural
(235.1 ha)
1509
1844
10,288
443
5532
5813
3880
3349
24,970
261
4335
5647
129
114
44
38
341
25
2571
1816
2427
589
784
971
Aggregate Length (m)
Formal Trails
Informal Trails
Disturbance Area (m2)
Formal Trails
Informal Trails
Lineal Extent (m/ha)
Formal Trail Length
Informal Trail Length
Density (m2/ha)
Formal Trails
Informal Trails
The Seven LNT Principles
1. Plan Ahead and Prepare
2. Travel and Camp on Durable Surfaces
3. Dispose of Waste Properly
4. Leave What You Find
5. Minimize Campfire Impacts
6. Respect Wildlife
7. Be Considerate of Other Visitors
1. Plan Ahead and Prepare
Schedule your trip to avoid times/areas of high use.
 New campsites are often created on high use
weekends. Even a few nights camping each year
prevents their recovery.
 The potential for social impacts (e.g., crowding and
conflict) is far greater during high use periods.
1. Plan Ahead and Prepare
Schedule your trip to avoid times
when resources are vulnerable.
 Vegetation and soils are far more
susceptible to impact when wet.
 Wildlife are more sensitive to
disturbance during mating,
nesting/birthing, and winter
seasons.
2. Travel and Camp on Durable Surfaces
Experimental trampling studies reveal that trampling
impacts can be avoided/minimized when you:
 Best: Stick to rock and naturally barren substrates,
 Best: Walk on the center of well-established trails or
camp in the core barren portions of campsites,
 Good: Confine traffic to non-vegetated organic litter,
 OK: Confine traffic to dry grasses; avoid herbs.
Resistance and Resilience: Forbs
1000 passes
0 passes
1 mo. later
Forest forbs generally
have low resistance
and resilience.
250 passes
Resistance and Resilience: Grasses
1000 passes
0 passes
1 mo. later
Grasses generally
have high resistance
and resilience.
250 passes
Vegetation Impacts
Vegetation trampling
Reduction in height
Compositional change:
Fragile to resistant
Native to non-native
Loss of vegetation cover
Soil Impacts
Trampling and
pulverization of
organic litter
Loss of organic litter
Compaction of soil:
Increased runoff
Decreased soil moisture
Use-Impact Relationships:
A Campsite Example
Impact (%)
100
80
60
40
The majority of most types of
impact occur at low use levels
20
0
0
10
20
30
40
50
60
Nights/Year
Vegetation Loss
Seedling Loss
Soil Exposure
Soil Density
Litter Loss
70
Rationale for Dispersal & Containment Strategies
The Use/Impact Relationship
What are the implications of the
curvilinear use/impact relationship for
selecting a low-impact campsite?
Amount of Use
Rationale for Dispersal & Containment Strategies
The Use/Impact Relationship
a
.
Consider an area where camping
is unregulated with 3 sites that
receive 15 nights/yr
.
15
Nights/Year
Rationale for Dispersal & Containment Strategies
The Use/Impact Relationship
All permanent impact could be avoided if use
from the 3 campsites could be dispersed to 45
sites, each with 1 night of camping/year.
.
1
Management experience has shown this level
of dispersal to be exceedingly difficult to
achieve.
Nights/Year
Rationale for Dispersal & Containment Strategies
The Use/Impact Relationship
b
a
.
.
.
15
A containment policy is more effective.
Use from 2 closed campsites is shifted to
the 3rd. Cumulative impact is reduced
from a (3 x a) amount of impact to a
(1 x b) amount of impact.
Nights/Year
.
45
Impact
Temporal Trends:
Life-History of a Campsite or Trail
1 yr
Time
10-30 yrs
Impacts occur quickly; recovery can require up to 30 yrs.
Implications: Use only well-established sites & trails;
avoid lightly impacted sites/trails to promote their recovery.
Traveling
In popular areas:
Stay on designated or wellestablished trails whenever
possible.
In pristine areas:
Disperse traffic on the most
resistant pristine surfaces if
you must leave trails.
Camping
In popular areas:
Stay on designated or wellestablished campsites.
Restrict activities to the
most highly disturbed areas.
In pristine areas:
Choose a pristine site with
resistant surfaces. Disperse
activities to avoid impact.
3. Dispose of Waste Properly
 Studies have shown bacteria to be present one year
after cat-hole waste burial. Decomposition is aided by
stirring the waste together with soil and water.
 Pathogens can effectively filtered from water moving
through < 5 feet of medium-textured soils so cat-holes
do effectively protect water resources.
 Desiccation, high temperatures, and UV radiation are
lethal to pathogens but are highly effective only for
thinly smeared surface-deposited waste.
3. Dispose of Waste Properly
Recommendations: Use toilets, carry-out, or cat-hole
wastes.
 Surface deposition is problematic due to aesthetics,
animal and insect transmission of diseases, and the
greater potential for water contamination.
 Burial (6-8”) in fine-textured soil >200 ft from water.
 Group latrines not recommended – the large mass of
wastes would slow decomposition time.
 Snow – carry-out is the best option.
4. Leave What You Find
Avoid introducing or transporting non-native species.
 Studies have surveyed hikers at trailheads and found
numerous seeds on the clothing of hikers and in their
gear. Clean your clothing, boots, and gear of seeds before
you depart home.
 Many non-native plants remain in the vicinity of trails
and campsites. However, a few highly invasive plants are
able to out-compete native vegetation in undisturbed
environments (e.g., Japanese stilt grass)
 Researchers have also germinated non-native seeds that
have passed through the intestines of horses.
4. Leave What You Find
Leave flowers for others to see. Picking them prevents
formation of seeds vital to their reproduction and survival.
A Great Smoky Mtn. NP study found significantly fewer
orchids along trails in comparison to more distant areas.
5. Minimize Campfire Impacts
Campfires can cause lasting impacts to the backcountry.
Research shows that campfire-related impacts are both
socially and ecologically significant.
 Campfire sites remind others that the area is not pristine,
large mounds of charcoal with trash are an eyesore,
firewood depletion can leave a human “browse line” and
tree damage and stumps represent acts of depreciative
behavior.
 Tree cutting removes dead trees important for cavitynesting wildlife. Firewood depletion diminishes nutrient
cycling and soil macro-fauna. Campfires produce long-term
changes in soil physical and chemical properties.
5. Minimize Campfire Impacts
Avoid campfirerelated impacts
by using a stove.
A study of backcountry
camping impacts at Great
Smoky Mountains National Park
found 2,377 damaged trees and
3,366 stumps!
Leave woods tools at home
6. Respect Wildlife
 Research shows that small mammal populations supported by
human food reach unsustainable levels that promote disease
transmission or starvation during the off-season.
 Another study found that the cessation of long-term artificial
feeding left some animals with an inability to locate natural
food. The young of such animals may never learn to forage for
natural foods – tantamount to a death sentence.
6. Respect Wildlife
Keep wildlife wild.
Never feed wildlife or allow
them to obtain human food or
trash.
Wildlife attracted to human
food often suffer nutritionally,
alter their natural behavior and
expose themselves to predators
and other dangers.
Managers at Grand Canyon had
to kill 22 fed deer, some with
up to 5 lbs of plastic clogging
their intestines. A fed deer in
Yosemite killed a small child.
6. Respect Wildlife
Displacement – animals are forced away from preferred
habitats e.g., food/water sources or cover, either during
certain times (temporal displacement) or in certain places
(spatial displacement).
New habitats are
unfamiliar, often have
lower quality food and
cover, or increased
competition and
predation.
7. Be Considerate of Other Visitors
Social Research on Group Size
Studies reveal that > 2/3rds of wilderness visitors report
that seeing large groups reduces their feeling of solitude
and being in wilderness.
 However, group size is generally among the lowest
ranked problems in comparison studies and < 50%
report that seeing large groups is a problem.
 Research indicates that a group’s actual behavior is
more important than its physical size. Large groups
can camp quietly away from others and adopt low
impact camping practices.
Ecological Research on Group Size
Only one empirical study and several suggestive
studies…
 Large groups burned more firewood, but less wood per
person, than smaller groups.
 Wildlife would likely be less disturbed by a smaller
number of larger groups than by a larger number of
smaller groups.
 Large groups can reduce their impact by staying on wellestablished trails and campsites – a dispersal strategy is
more difficult for large groups.
Ecological Research on Group Size
Large groups substantially expand campsites when they camp
even one night on a site that’s too small. Any subsequent
use of newly expanded areas prevents recovery.
Large groups can reduce their impact by:
 breaking into smaller groups to hike and camp,
 confining their activities to already impacted areas
away from other groups,
 meeting infrequently as a large group and only on
durable surfaces, and
 practicing quiet and courteous behavior.
The End
Happy trails and remember to . . .
Sunset, Haleakala Volcano, Haleakala National Park, Hawaii
Leave No Trace !