00:00

Question 72·Hard·Cross-Text Connections

Text 1
After gray wolves were reintroduced to Yellowstone National Park in 1995, field biologist William Ripple and colleagues observed that browsing pressure on young willow and aspen near streams diminished markedly. They argued that elk, wary of the newly present predator, spent less time foraging in open river valleys, allowing saplings to mature into dense stands that stabilized streambanks. In a 2004 article, Ripple suggested that this vegetation recovery reduced erosion and "helped rivers reclaim their pre-1900 meanders."

Text 2
Geomorphologist Ellen Wohl agrees that predator–prey dynamics can influence vegetation but contends that changes to channel shape claimed for Yellowstone are overstated. Using aerial photographs from 1930 through 2020, Wohl found no systematic shift toward greater sinuosity in reaches adjacent to recovering willow. She notes that river morphology in the park is largely governed by snowmelt-driven discharge and sediment supply—factors unaffected by wolf predation—and that beaver dams, not tree roots, are the primary agents of bank stabilization in these systems.

Which choice best describes how Text 2 relates to Text 1?