1. Leave No Trace Outdoor Skills and Ethics The Science behind the Practices
This presentation is intended for the Master Educator course. It is a non-technical presentation but it is helpful if the presenter has a science background or has read some of the more relevant studies. T2 T3 T5 I2 I3 I4 I1 T4 I5 T1 T6
Soil Loss

2. 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 presentation includes findings from only a portion of the available and relevant research. Participants can find out more by consulting the LNT website’s listing of relevant studies.
The principle objective is to demonstrate that LNT practices are science-based, and to explain the rationale behind some of the low-impact practices we use.

3. 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.
Recreation ecology is a field of study that investigates recreation-associated impacts to the resources of protected natural areas.
These studies commonly examine vegetation and soil impacts associated with trampling along trails, recreation sites, and campsites, and impacts to wildlife impacts associated with disturbance by recreationists or their food.
Relational analyses help to define the relative influence of various factors, such as the amount, type, or behavior of visitors vs. the resistance of different vegetation types or the influence of soil wetness.

4. The LNT Message
Social science research tells us about visitor attitudes, behaviors, social norms, and effective methods of communicating low impact practices.
Many social scientists also study visitors through survey research to better understand the causes of different visitor behaviors and how such behaviors can be modified through education.

5. Haleakala National Park
This simulation was developed by social scientists and shown to park visitors to evaluate their perceptions about the acceptability of informal (visitor-created) trail proliferation.
These “off-trail” impacts are an increasing concern of managers at many parks and forests.
Haleakala National Park
(Simulation - proliferation of informal trails) 5

6. Informal (Visitor-Created) Trail Impacts
Indicators
Park Zones
Developed
(11.7 ha)
Threshold
(16.2 ha)
Natural
(235.1 ha)
Aggregate Length (m)
Formal Trails
1509
1844
10,288
Informal Trails
443
5532
5813
Disturbance Area (m2)
3880
3349
24,970
261
4335
5647
Lineal Extent (m/ha)
Formal Trail Length
129
114 44
Informal Trail Length 38
341 25
Density (m2/ha)
2571
1816
2427
589
784
971
Here’s some results from a recreation ecology study of informal trail impacts in the Potomac Gorge, near Washington, D.C. Survey staff used Global Positioning System (GPS) devices to map all informal trails (shown in red) and formal trails (shown in blue).
Managers were shocked to discover the substantial number and area of trampling disturbance associated with the hiking that occurs off of formal trails. This area is known for its large number of rare plants and sensitive plant communities.

7. 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
Lets look at some of the research related to each of the 7 Leave No Trace principles. Some practices are based on the best judgment of land managers and outdoor educators, but many are also based on scientific research.

8. 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.
Many protected areas have considerably larger numbers of campsites than are necessary to support their actual demand on all but peak use weekends.
The extra campsites can be thought of as “avoidable impact” – why have 50 campsites along a trail that only has to accommodate 10 groups on high-use weekends?
Campers can help by never “pioneering” a new campsite and by avoiding popular areas or camping on peak use weekends.

9. 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.
Trampling impacts to vegetation and soils are substantially greater during wet weather, particularly for horse and bike traffic.
Wildlife are also more easily disturbed during certain highly sensitive seasons.

10. 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.
Numerous studies in the U.S. and overseas have repeatedly shown that vegetation and substrates vary considerably in their resistance to trampling impacts.
The easiest rule of thumb is to pay close attention to how the surfaces you recreate on react to your activity. Even bedrock may have foliose lichens that can be easily damaged from traffic. Concentrate your activities on the most durable surfaces available.

11. Resistance and Resilience: Forbs
1000 passes
0 passes
1 mo. later
250 passes
Forest forbs generally
have low resistance
and resilience.
Scientists have conducted small experimental trampling studies to evaluate the resistance to trampling impacts and their resilience (ability to recover) following trampling.
These studies reveal that broad-leafed herbs that grow under forest canopies are very susceptible to trampling damage and they also recover very slowly.

12. Resistance and Resilience: Grasses
1000 passes
0 passes
1 mo. later
250 passes
Grasses generally
have high resistance
and resilience.
In sharp contrast, trampling studies reveal that grasses, which grow best in open, sunny locations, are very resistant to traffic and recovery quickly after being trampled.
If you can’t find more durable surfaces (rock, bare soil/gravel, or snow) to camp or walk on, then try to stay off broad-leafed herbs and find grassy areas to camp or hike on.

13. Compositional change: Loss of vegetation cover
Vegetation Impacts
Vegetation trampling
Reduction in height
Compositional change:
Fragile to resistant
Native to non-native
Consider how vegetation reacts to trampling. The height of vegetation is reduced very quickly, just one night’s camping or a few passes through pristine vegetation.
A few more nights of camping and vegetation cover will be lost entirely in the most trafficked areas.
Over time vegetation that is fragile will be lost and replaced by trampling-resistant species. This composition change can occur with native species, but often the new plants are non-native (exotic) species.
Loss of vegetation cover

14. Trampling and pulverization of organic litter Decreased soil moisture
Soil Impacts
Trampling and pulverization of organic litter
Loss of organic litter
Compaction of soil:
Increased runoff
Decreased soil moisture
As vegetation cover is lost on campsites or along trails the organic litter becomes exposed, trampled, and pulverized.
With more traffic the organic litter is entirely lost, exposing the underlying soils to compaction, which increases water runoff and soil erosion.
Over time soil erosion eventually exposes plant roots, making the vegetation more susceptible to droughts.

15. Use-Impact Relationships: A Campsite Example
100 80 60
Impact (%) 40
The majority of most types of
impact occur at low use levels
Campsite impact studies show that fragile vegetation and organic litter cover is largely lost with as little as 10 nights of use/year. When creating new campsites, campers frequently pull out tree seedlings and cut down saplings and shrubs to create spaces for their tents and a fire site or cooking area.
In sharp contrast, 10 additional nights of camping on a campsite that receives 40 or 50 nights of use/year has very little measureable effect. 20 10 20 30 40 50 60 70
Nights/Year
Vegetation Loss
Soil Exposure
Litter Loss
Seedling Loss
Soil Density

16. 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?
Research across the country repeatedly has demonstrated a curvilinear relationship between trampling and many types of resource impact. What are the implications of this finding?
Amount of Use

17. Rationale for Dispersal & Containment Strategies The Use/Impact Relationship15 a .
Consider an area where camping
is unregulated with 3 sites that
receive 15 nights/yr
Impact
Let’s consider an example from research at Shenandoah National Park. Consider a cluster of 3 campsites that each receive about 15 nights of camping/year.
This level of use has already removed most of the vegetation and organic litter cover and tree seedlings, saplings, and shrubs on these sites. That’s 3 campsites, each with aggregate (cumulative) impact at the “a” level.
Nights/Year

18. 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.
Management experience has shown this level of dispersal to be exceedingly difficult to achieve.
Dispersal . 1
Impact
Now, if the use (15 nights/yr) that created those 3 campsites had been effectively dispersed to just a single night of camping on 45 different sites then virtually no measureable camping impact would be detected if you returned to those 45 sites a year later.
Unfortunately, land managers have rarely had success getting campers to do this type of dispersed “pristine site” camping. What are some reasons?
There often are not a sufficient number of flat suitable places to support dispersed camping.
Campers prefer camping on pre-existing campsites - they are easier to find and use. Even minimal camping on lightly-used sites prevent their recovery.
Campers lack the skills to do pristine site camping.
Nights/Year

19. Rationale for Dispersal & Containment Strategies The Use/Impact Relationshipb 45
Close 2 campsites . 15 a .
Impact
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.
The lack of success with dispersed camping has caused most land managers to practice a “containment” strategy. Using our example, they would try to limit campsite numbers and aggregate impact by concentrating camping on the smallest possible number of heavily-used campsites.
Research shows that if they closed 2 of the 3 moderately used sites and shifted that use to the most sustainable site, that aggregate impact would drop from 3 times an “a” level of impact to 1 times a “b” level of impact.
Campers can help by avoiding lightly impacted sites and using well-established and highly impacted campsites. Keep these small by setting up tents and cooking only within the higher impact core parts of the site.
Nights/Year

20. Temporal Trends: Life-History of a Campsite or Trail
Establishment
Closure
Full
Recovery
Impact
Time
1 yr
10-30 yrs
Research has also shown that trampling impacts occur relatively quickly on new campsites or trails but recovery is a much slower process that requires a very long time.
The implication of this finding for Leave No Trace is that visitors should avoid creating new campsites or trails. Stick to well-established campsites and trails or find resistant rock and naturally barren substrates to take rest or lunch breaks on.
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.

21. Traveling In popular areas: In pristine areas:
Stay on designated or well-established trails whenever possible.
In popular areas:
Disperse traffic on the most resistant pristine surfaces if you must leave trails.
In pristine areas:
Most visitors should practice the containment strategy by concentrating their traffic on well-established formal trails.
If your group is smaller and experienced in dispersed hiking then you can venture off trails into more pristine areas. Disperse your hiking on the most resistant surfaces available. If resistant surfaces are unavailable you should strive to disperse traffic to a single pass when traveling or going to and from water sources or tents.

22. Camping In popular areas: In pristine areas:
Stay on designated or well-established campsites. Restrict activities to the most highly disturbed areas.
In popular areas:
Choose a pristine site with resistant surfaces. Disperse activities to avoid impact.
In pristine areas:
In most areas that receive moderate to high use you can best limit your impact by camping on designated or well-established campsites.
If your group is smaller and experienced in “pristine site camping,” you can overnight in more remote trail-les areas. Search around to locate your campsite on snow or naturally occurring barren rock, gravel or soil. If your activities are not causing noticeable impact, then you can camp multiple nights. If impact is becoming visible then move your campsite every night.

23. 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.
You can speed decomposition in a cat-hole by using a stick to stir the waste with soil and water. Wet toilet paper also disaggregates quickly so this is an effective option if you can’t carry it out. This practice may be inappropriate for youth – use your judgment!
Surface disposal is effective only when thinly smeared and aesthetics and insects remain a significant problem.

24. 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.
Use toilets when available but “carry-out” is always the next best option, followed by cat-holes.
There are a variety of portable toilet and “carry-out” kit options. Research these options through internet searches.

25. 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.
You’d be surprised at how many seeds may be lurking in your gear or stuck to the bottom of your tent or boots. Protected area managers are fighting a losing war against non-native invasive plants. Help them and preserve your access to the public lands by not transporting seeds into protected areas.

26. 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.
Kids are often the most significant culprit here, though some adults can’t resist picking beautiful flowers to take home or give to a loved one.
Picking flowers means removing the ability of that plant to reproduce! What if 600 million visitors to our public lands each picked just one flower a year…

27. 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 cavity- nesting wildlife. Firewood depletion diminishes nutrient cycling and soil macro-fauna. Campfires produce long-term changes in soil physical and chemical properties.
Campfire related impacts are the bane of every backcountry or wilderness Ranger. After you’ve dug out and cleaned trash from 100+ fire sites and seen thousands of damaged trees and stumps you’d feel the same way they do. Most land managers want to just prohibit campfires and many have.
Campfires are a privilege, not a right!

28. 5. Minimize Campfire Impacts
Avoid campfire-related impacts by using a stove.
Unless you really need a campfire, don’t build one.
If you do build one, use only existing fire sites, a fire pan, or a mound fire. Keep it small and lit for a short time to preserve firewood. Leave woods tools at home and collect only dead and downed wood you can easily break by hand. Burn only wood, and when possible, burn all of it to ash. Before you leave, use ample water to douse the fire completely, crush charcoal and clean it of trash, then scatter it widely away from camp. Rearrange the stones to make a small fire site (2-3 ft wide).
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

29. 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.
Numerous studies have documented many detrimental effects when wildlife obtain human food. While visitors may think they are helping the “poor starving” animals, they are actually profoundly altering their behavior in ways that will shorten, not lengthen, their lives. This applied to all animals, from small mammals to deer or bears.

30. 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.
Even small seemingly insignificant scraps of food and strong food smells are sufficient to start wildlife down the path to harmful food attraction behaviors. Fed just once or twice, they will return to campsites and lunch sites repeatedly, eventually becoming beggars or pests that will bite a visitor or tear holes in gear.
The goal here is to not drop or spill any food and to store all food safely from animals at all times.

31. 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.
Whenever animals flee our presence remember that they are moving from their preferred habitat to habitat that is less able to sustain them and may actually be dangerous to them.
When you see wildlife behave in a way that least disturbs them. Remember, you are one of 600 million visitors to the public lands. Everyone’s actions count!

32. 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.
Even frontcountry visitors prefer not to see and hear lots of other people when they recreate. Large groups, particularly of youth, are often noisy but they don’t have to be.
Large groups can behave in a manner that protects the environment and allows others they encounter to have a high quality experience. Learn and apply large group low-impact practices! It’s more about behavior than about group size.

33. 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 well-established trails and campsites – a dispersal strategy is more difficult for large groups.
Some significant resource impacts associated with large groups include those related to expanding the sizes of campsites, building large bonfires, and using up lots of firewood.
Dispersed “pristine site” travel and camping are much more challenging for large groups, particularly with youth. It’s best to stick to well-established trails and campsites.

34. 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.
One of the most important practices for large groups is to split your group to use only well-established campsites, carefully matching the number of tents to the available barren tent sites.
Consider not having a campfire, or build a small one for just a few hours. Only congregate around a pre-existing campfire site or fire pan that has sufficient barren ground around it to support your group size.
Camp away from others, or take special care to remain quiet and courteous.

35. The End Leave No Trace ! Happy trails and remember to . . .
Developed by Jeff Marion,
Happy trails and remember to . . .
Leave No Trace !
Sunset, Haleakala Volcano, Haleakala National Park, Hawaii