CHURCHILL, Manitoba (AP) — Sgt. Ian Van Nest rolls slowly through the streets of Churchill, his truck outfitted with a rifle and a barred back seat to hold anyone he has to arrest. His eyes dart back and forth, then settle on a crowd of people standing outside a van. He scans the area for safety and then quietly addresses the group’s leader, unsure of the man’s weapons. “How are you today?” Van Nest asks. The leader responds with a wary, “We OK for you here?” “You’re good. You got a lot of distance there. When you have people disembarking from the vehicle you should have a bear monitor,” Van Nest, a conservation officer for the province of Manitoba, cautions as the tourists gaze at a polar bear on the…