1. How Disturbance Impacts Wildlife
By Lauri Turner, Forest Wildlife Program Manager, Deschutes National Forest, Supervisor’s Office,

2. Direct Effects Death or Injury Habitat Loss From collisions
Could have population level changes if dealing with low density populations
Habitat Loss
Direct loss of habitat due to road and/or trail construction

3. Indirect Effects – Habitat Degradation
Increased compaction – may reduce vegetation, not allow burrowing into soil, etc.
Trampling of Vegetation
Spread of Invasive Species
Bare ground allows invasives to get a foothold
Tires can serve as a vector for spread

4. Habitat Degradation Increased sedimentation potential
Roads and trails within riparian reserves serve as sedimentation sources
Especially where there are social trails to the river/stream’s edge
Loss of habitat components like snags and down woody material
Hazard trees cut along system roads and trails
Taken as firewood

5. Habitat Degradation Garbage Dogs Can lead to habituation to humans
Can lead to health problems for animals
Dogs
Chasing animals can reduce energy reserves and if caught may result in injury or mortality
Could spread disease

6. Habitat Quality - Disturbance
Wildlife Displacement
Displaces animals either temporarily or permanently
Flushing animals when present – interrupts foraging, causes increased energy expenditures, etc
May cause nest abandonment
Habitat Avoidance
Lower population densities near roads/trails
Example – Ryan Ranch Key Elk Area
Elk avoid Ryan Ranch and the Deschutes River during the daytime due to human presence – have shifted use to nighttime

7. Habitat Quality - Disturbance
Acute or chronic physiological damage (i.e. hearing loss)
If subjected to loud noises (above ambient noise levels – i.e. ATV or motorcycle use), some species have experience hearing loss
This can lead to increased predation potential, unable to hear mating calls, etc.
Increased energy expenditures
Usually results from being flushed (i.e. deer along roadside)
Compounded if it occurs during a high energy need period (i.e. winter, feeding young)

8. Habitat Quality - Disturbance
Physical injury due to panicked responses
Interference with normal activities (i.e. feeding, breeding)
Noise may emulate natural sounds and cause inappropriate effects (i.e. emerging during the wrong season)
Impaired communication among individuals or groups
Human-made noise interferes with animal communication signals, sounds animals listen for orientation, and predator-prey detection
Interferes with ability to capture prey

9. Habitat Quality - Disturbance
Increased stress hormones
Leads to reduced reproductive success
Altered behaviors
Shifting periods of use
Using lower quality habitat
Aggression
Altered nest/den placement

10. Connectivity and Barriers
High landscape connectivity is a landscape that has few barriers and where animals can move freely – moving through different habitats in order to meet daily and life needs
High landscape connectivity allows for movements to re-populate areas and minimizes inbreeding

11. Connectivity and Barriers
Barriers can be a variety of things depending on the species
Examples include unsuitable habitat, roads/trails, waterways, urban areas, etc.
Barriers that impede movement result in higher mortality, lower reproductive success, and smaller populations
Isolation caused by barriers to movement can reduce gene flow leading to genetic effects

12. Fragmentation Fragmentation
Decrease some habitat type in a landscape OR
Apportionment of habitat into smaller, more isolated patches
Roads and trails result in large patches being dissected into smaller patches
Reduces interior forest habitat and increases edge effect
Long and linear = more edge habitat
Impacts are not all equal – areas with high diversity (i.e. riparian habitats) may experience greater impacts