Walk through grasslands, woodlands and coastal sage scrub Saturday on the Rancho Mission Viejo Land Conservancy, the city's own nature preserve in the San Clemente/San Juan Capistrano foothills. The guided, one-mile nature walk will start at 9 a.m. and last more than two hours. A donation of $3 for adults and $2 for children is suggested. The 2,100-acre preserve was turned into the county's first land conservancy in 1990 for ecological preservation, research and public education in exchange for the right to develop the future 3,510-acre Talega community. Reservations are required: (949) 489-9778.