Forest Habitat Degradation

 

Roads

Roads present physical barriers to many small species and impede water flows.  Carabid beetles and Wolf spiders have been shown to be blocked by roads as narrow as 2.5 meters. Studies show the probability of small mammals crossing roads of 6-15 meters in width is less than 10% of that for adjacent habitats, and macroinvertebrate density and leaf litter abundance is affected for 100 meters beyond the road itself.

Studies show the effects of logging roads have been found to persist for 80 years or more.  This ecological 'footprint' supersedes regeneration of the forest itself.  With logging rotational cycles of 80 years or less, footprints of logging roads from past harvests will not be gone before a new footprint is laid down, and the effects will accumulate over time, eventually fragmenting the forest into ever-smaller patches of suitable habitat."  

The area degraded by a road varies by traffic volume and road width. Degrading road effects include:

·        direct road kill

·        avenues along which non-native species flourish and spread

·        noise and light

·        wind drying effects

·        erosion

·        silt, sand, salt runoff

·        herbicide applications

Clearings and openings

• removes trees and plants that provide many beneficial services such as cleaning air and water
• changes the structure of plant species to favor pioneer species that prefer sunlight
• provides openings where non-native species thrive
• sun and drying effects kill many interior forest species
• abundance of forest species like salamanders is greatly degraded

Maps showing degraded forests areas (buffered widths shown beyond openings themselves)

• Interstate Highway -1000 feet on each side
• County paved roads – 600 feet on each side
• Transmission lines – 300 feet on each side
• Logging roads – 300 feet on each side
• Logged areas – 300 feet on each side
• All Terrain Vehicle Trails - 300 feet on each side
• Railroad Tracks - 300 feet on each side

Maps showing degraded areas

• Map1 showing degraded areas from Interstate Highways and transmission lines
• Map2 showing degraded areas from state roads and transmission lines
• Map3 showing degraded areas from logging, logging roads, and all terrain vehicle trails
• Map4 combined map showing all degraded areas