Summary and Key Findings
Which animal may have increased in number as an indirect result of wolf predation?
Bison
What was the relationship between elk and bison populations before wolves were reintroduced to Yellowstone?
Elk and bison populations were positively correlated.
Wolves were re-introduced to Yellowstone in the early 1800's
False, they were reintroduced in 1995/1996.
Do elk and bison compete for food or habitat?
They have competitive dietary overlap and compete for forage.
What was the relationship between elk and bison populations after wolves were reintroduced?
They had a strong inverse relationship (r = −0.84).
Both bison and wolves can have important effects on the ecosystem.
True
How does bison use of the northern range differ from elk use?
Bison are present in larger numbers during both summer and winter, while elk primarily use the northern range in winter.
What statistical analysis was used to test whether the relationship between elk and bison populations changed before and after wolf reintroduction?
Multiple regression.
Within 10 years of increasing wolf presence and declining elk populations, there was evidence that young plants were growing taller in portions of Yellowstone's northern range.
True
Based on the article, what potential effects could increased bison populations have on woody plants and riparian conditions?
They could have negative effects through increased browsing of woody plants and trampling and erosion of riparian streambanks.
What type of graph did the article use to show the relationship between elk and bison populations?
A scatter diagram
The article established that gray wolves alone might be able to limit contemporary bison populations.
False. It is unknown how often and under what circumstances gray wolves alone might be able to limit contemporary bison populations.