Physical Impacts

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Physical Impacts Their Management - 5/14/03
course website
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Wilderness Visitor Impacts

• human trampling
• fires firewood collecting
• wastes
• pack stock trampling/grazing
• introducing noxious species
• degraded water quality

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Most impacts localize to small portion of
area. But, thats the area where people are
concentrated. Thus impacts can be
bothersome. But, to whom?
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A few impacts affect larger wilderness ecosystems

• fish stocking/harvesting (catching)
• disturbing wildlife
• loss of rare/endangered species
• water quality

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Trampling impacts vegetation soils
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Durability of vegetation associated with

• small leaves
• trailing habit (as vines)
• protected growing tissue buds
• basal rosette
• thorns

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• Grasses sedges
• grow from base
• tougher in full light vs. shade
• Forbs (broad-leaved herbaceous)
• easily damaged (esp. when tall)
• less so if basal rosette
• replaced when trampled

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Vegetation especially vulnerable in spring, when
small tender. Soils often wet vulnerable at
same time. Importance of photosynthesis requires
ample leaf area provides energy for seed on new
growth
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• Soils 101
• Soil is
• a growth medium (ideally porous)
• a bearing surface for foot traffic

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• Texture refers to particle size
• sand (coarse)
• silt (fine)
• clay (extremely fine)

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Soil Triangle
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• Soil Structure
• aggregates of finer particles that behave
  like tiny pebbles
• helps maintain pore space
• may be lost with compaction, esp. when wet
• reduced pore space less oxygen, water, root
  penetration

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• Typical soil profile
• organic debris on top
• can act as pad
• reduces erosion
• protects from rain
• filters out particles

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• Soil as bearing surface
• needs strength
• weaker when wet
• needs to let water in
• Erosion increases rapidly with steepness of slope

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Fires

• direct damage to vegetation
• damage to soil itself (lost organic matter
  microorganisms
• increased pH from ashes
• removal of wood from site

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• Wastes
• cat hole
• pit toilets
• nutrients
• pathogens
• soap, grease, toothpaste, trash

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• Pack saddle stock
• hooves have high pressure
• weeds in feed
• grazing(some built-in margin)

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• Fish issues
• amphibians, etc.
• changed species abundance
• Wildlife disturbance
• energy to avoid people
• use less suitable habitats

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• Rare Endangered Species
• direct damage to plants
• competition from invasives
• harassment of wildlife
• Water quality
• pathogens
• nutrients
• sediment

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• So what? Handling Impacts
• separate what occupied from what experience
• first use has greatest impact (see text fig.
  15.12)

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• Design to make it easy to do the right thing
• rationalized trail network
• block social trails
• concentrate rather than disperse use (some
  exceptions)
• use durable sites
• minimize fire locations

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• use young stands of trees (??)
• control pack stock
• high lining
• processed feeds
• facilities
• 12-heart limit

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(No Transcript)
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• Human wastes
• honey bucket system
• pack it out
• on-site composting (??)

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• Trails
• slender sacrifice zone
• often not designed
• avoid wet areas
• control water (thus erosion)
• short cutting

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• Impacts on wildlife
• Critical periods
• breeding nesting seasons
• winter
• Critical places
• dens, water holes, feeding areas