Results

  

Liberty Canyon Corridor

    (Liberty Canyon interchange with US 101, Los Angeles County, California. Image obtained from Google Earth, edited with Microsoft Paint.)

After considering the current plans for creating a wildlife corridor near Liberty Canyon Road, in Los Angeles County, and after reviewing the collected satellite data we have garnered some concepts to assess the location of further wildlife corridors in the region. Firstly and obviously, the crossing site will have little chance of being implemented on or near existing development as it will inhibit wildlife access and the costs would be too great. Secondly, the corridor has an almost unbroken string of undeveloped land that is nearly wild and has a relatively consistent NDVI signature. Third, the corridor connects on both sides to a much larger swath of habitat as this is key to the success of a wildlife corridor. Fourth, the area chosen has high relief on both sides of the crossing limiting development potential and enabling a bridge or tunnel to be implemented with ease. 

Of note in the spectral profile is the mid to low value range averaging between 0.1 and 0.2 signifying that the vegetation on either side of the corridor is not necessarily high in cover value, such as a woodland would be, showing that the unbroken corridor was selected in favor of the more wooded areas to the east along the streambeds. According to the thermal imagery, we determined that they seemed to prefer the warmer grasslands for the corridor as opposed to the cooler forests, but this placement choice was undoubtedly driven by the development in the region as opposed to relevant satellite data.

Conejo Grade Corridor

    (Conejo Grade via Us 101, Ventura County, California. Image obtained through Google Earth, edited with Micorsoft Paint.)

The Conejo Grade study area shows discouraging signs for the potential development of a wildlife corridor given the data assessed. Some positive aspects toward corridor development are represented in the satellite data such as the lack of development up and down the pass, save for a freight weigh station, and stark relief on either side of the freeway. These would lead to a positive assessment of the data, however, the negative aspects are numerous. The vegetation values in this region, according to the NDVI density slice, were some of the lowest in the entire study area indicating a drastic lack in healthy chaparral habitat. The North South spectral profile along one of the potential corridor routes did not even have a value of 0.2 and consistently is below 0.1 indicating very low turbidity in the vegetation through the corridor.

This is expected due to the recent burn activity in the area combined with the drought conditions but the effect is compounded when observing the trends of the Liberty Canyon corridor. The burn is contained to the south side of the freeway and in some cases charred all the vegetation on the hillside leaving zero cover or food for herbivores. The north side of the freeway is relatively unscathed, yet in no way pristine habitat, and the combined effect leaves almost no connectivity between the two sides and little corridor value as a whole. As the Springs Fire’s path had it tear south through Point Mugu State Park, the major habitat this corridor would connect is also degraded by fire and drought.

Newhall Pass Corridor

    (Newhall Pass via Interstate 5, Los Angeles County, California. Image obtained through Google Earth, edited with Microsoft Paint.)

San Fernando Pass Corridor

   (San Fernando Pass via Sierra Hwy and Highway 14, Los Angeles County, California. Image obtained through Google Earth, edited with Microsoft Paint.)

Since the Newhall pass had options, it was thought best to review two potential wildlife corridor options; one corridor over Interstate 5 south of the 5-14 interchange, or two corridors north of the interchange over the respective freeways.

The potential of a wildlife corridor south of the 5-14 interchange was thrown out as an idea almost immediately. Interstate 5 is at some points 12-14 lanes wide south of the interchange and is heavily urbanized on both sides leading up to the interchange. One small section of the freeway south of the interchange that does not have dense urban development in the form of buildings or industrial landclearing would seem like a suitable site given the relief of the hillsides and small available vegetation. The spectral signature was sent through this crossing as a potential site. On further inspection from high resolution satellite imagery the east side of the crossing is the site of the Los Angeles Aqueduct’s downhill descent into Los Angeles, and Los Angeles is unlikely to grant use of the land for the corridor, regardless of any potential for biodiversity.

This seemed to point ultimately to look for crossings north of the 5-14 interchange as anything south was unsuitable, even though the cost of two wildlife corridors would have to be assessed for the connection to be completed. After the grim results reviewing the potential for a corridor south of the interchange, the favorable conditions north of the interchange quickly lifted spirits once the data had been reviewed. Both freeways had suitable corridor sites based on the parameters we have been following such as strong relief on the sides of the crossing and a lack of development on either side. Furthermore, the study area had great sets of connectivity for the individual crossings with large sections of intact habitat as destinations after the crossings and consistent signatures traversing the crossings. Despite the elevated costs involved with multiple wildlife crossings for one corridor, the Newhall and San Fernando study areas remain one of the first choices in implementing a wildlife crossing based on helping biodiversity and the set parameters.    

Santa Susana Pass Corridor

   (Santa Susana Pass via 118 Freeway, Ventura and Los Angeles County, California. Image obtained through Google Earth, edited with Microsoft Paint.)

The Santa Susana Pass is perhaps the most promising of the study sites for the potential implementation of a wildlife corridor based on the preset criteria. The pass has little to no development on the north side of the freeway and widely spaced residential development along the few roads south of the freeway, otherwise unbroken potential habitat on both sides creating a usable corridor. This is supported by the spectral profile taken at the potential corridor site which gives the most consistent chaparral signature across any study site, aside from the dip in value when crossing the freeway. Both sides of the freeway have plenty of relief in the terrain to implement a corridor and the thermal imagery keeps the cool residential vegetation well to the sides of the wildlife corridor.

Possibly most important when considering this as a potential study site is that this corridor is connecting vital habitats when considering the Liberty canyon corridor is already being implemented. After the completion of the Liberty Canyon wildlife corridor the Santa Susana Pass represents the next link in the shortest chain connecting the Santa Monica Mountains to the Eastern San Gabriel Mountains. Even as it stands without the total chain being complete the Santa Susana Pass wildlife corridor would still be linking the Santa Monica Mountains to the Santa Susana Mountains connecting key habitats and extending the chances for biodiversity.

 Sepulveda Pass Corridor

   (Sepulveda Pass via Interstate 405, Los Angeles County, California. Image obtained through Google Earth, edited with Microsoft Paint.)

Surprisingly, even with the incredible amount of vehicular traffic that passes through on a daily basis, the Sepulveda Pass actually has viable wildlife crossing potential. The geography, or more specifically, the erosive nature of the canyons has led to steep relief in near slot-like canyons that run north-south. This has led to the Sepulveda Pass being the major route over the mountains but also has created a somewhat narrow margin to cross thanks to the steep relief, so there are sections with no urbanization other than the freeway and Sepulveda Boulevard. The selected crossing site is around 100 meters wide, while certainly above average, is not out of the question considering some of the immense wildlife crossings implemented around the world.

The NDVI and thermal imagery reveal what looks to be reasonably intact habitat south of the golf course which dominates the center of the NDVI imagery and this is complimented  by the small patch of habitat southwest of the Stone Canyon Reservoir. These small, paltry examples of habitat can only be viewed in the context that they are surrounded by Los Angeles, and therefore had amazing odds at surviving even this far. Lastly one has to consider that this already is a wildlife corridor. P 22 has already shown that this can be a corridor for movement of an apex predator from one piece of habitat to another, even if he had to go through some human’s backyard.