declined 95-99%. The Reserve is one of only four to six reproductively viable populations of the Southwestern pond turtle in southern California. Snakes found on the Ecological Reserve include: San Bernardino ring-necked snake, Hammond's two-striped garter snake, coastal rosy boa, Western yellow-bellied racer, California striped racer, San Joaquin coachwhip, red diamond rattlesnake, Southern Pacific rattlesnake, San Diego gopher snake, California kingsnake. Other reptiles include: San Diego horned lizard, western fence lizard, granite spiny lizard, side-blotched lizard, western skink, western whiptail, San Diego alligator lizard. Amphibians Amphibians found on the Ecological Reserve include: coast range newt, garden slender salamander, black-bellied salamander, western spadefoot toad, Pacific treefrog, California red-legged frog, bullfrog. Bullfrogs are an invasive species, which because of their superior size, takes over territory from native species. Geology The oldest rock seen on the Reserve is meta-volcanic rock, laid down 220-190 million years ago. Above that is found meta-sedimentary rock, consisting of slates, argillites and some quartzite and limestone beds. Gabbro, consisting of feldspar, pyroxene and olivine, was laid down 143-101 million years ago. The granite on the Plateau arrived 119-105 million years ago. Arkosic sand and gravel was deposited by flowing water approximately 23-9 million years ago. Olivine basalt is from a lava flow of 9-6 million years ago. Lichen Lichen found on rocks on the Reserve include species from genera Fruticose, Squamulose, Foliose, and Crustose. Common species found on large rock outcroppings include common greenshield lichen, beaded rosette lichen, sunken disk lichen and rim lichen. Lichen are a symbiotic relationship between various species of fungus, which provide the structure, and algae, which provide the organism's nutrients. Human history The first Native Americans are thought to have inhabited the area for more than 8,000 years. The Native Americans known as Luiseño, due to their connection to the San Luis Rey Mission, began to inhabit the area about 1,500 years ago. It is thought they only used the Plateau during the warm weather months, and to collect acorns in the fall. During the rest of the year they lived in the nearby Temecula Valley. They had a village called Meha near the ranch on the Plateau. The midden found at the village suggests it had been occupied for approximately 6,000 years. When visiting the adobes, one can see indentations in boulders used by the Native Americans to grind acorns and other food. Before the arrival of Spanish missionaries, the indigenous peoples