Bob Sharp, rancher, writer, photographer and environmental designer, knows it's impossible to halt the influx of new people to Southeast Arizona's seemingly endless borderlands, but he's determined not to let settlement spread where it may.

As the third and final speaker in this year's Arizona Senior Academy Sustainability Seminars, Sharp will offer insights and solutions that provide for people but keep the sweep, scale and character of this natural landscape secure into the future.

Sharp will speak from 3:30 to 5 p.m. Wednesday at the Arizona Senior Academy Building at Academy Village, an active-adult community off Old Spanish Trail six miles southeast of Saguaro National Park East.

Sharp believes that left unchecked, settlement will diminish open space, crowd out the solitude and change the grasslands environment people cherish. He believes in sensibly clustering settlement into smaller spaces.

Having grown up on the Sharp Ranch in the San Rafael Valley, Sharp knows the joy and work of ranching. He also knows its challenges: making a living in a tough environment; dealing with economic pressures to subdivide and sell; and knowing that dividing the land means losing many of the central qualities for nature, heritage and people.

An environmental designer, he believes environmental design principles can win the day. The question, he says, is whether we have the will to act on them.

Sharp's presentation is free and open to the public.

If you go

• What: The last in a a three-part series on sustainability seminars focusing on the borderlands of Southeast Arizona.

• When: 3:30 p.m. Wednesday.

• Where: Arizona Senior Academy Building at Academy Village, 13715 E. Langtry Lane.

• Admission: Free; donations accepted.

• Reservations: Recommended; email or call 647-0980.

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