A huge mountain lion barrier had to be built on I-15 just east of here in order to prevent mountain lion deaths. Hundreds of toads are killed with every rainstorm on just one road in the Fallbrook area, the De Luz Road, since they actually come out to sit on the road and absorb the moisture that is easily available during and immediately after rains. Fortunately, since traffic on the roads in SMER is extremely light, this isn't a problem here. However, other animals won't cross a road at all, and the road serves to fundamentally restrict their habitat. If the road creates too small a habitat, the animal will become extinct there.
Much research is ongoing to quantify the effects of roads for various species.
At mile 1.8, we reach the split between the shortcut that follows the route of the aqueduct, and the continuation of the Red Mountain Truck Trail that we are on. This is also roughly the boundary between the Diegan Coastal Sage Scrub and the Southern Mixed Chaparral. We now see more of the hard chaparral, including California Lilac. At mile 2.3 the road forks. On the right, the Red Mountain Truck Trail continues to the Rainbow Glen gate.