The researchers concluded that the number of bears has changed little in the past two decades, despite intensive grizzly bear management. Bear mortality is nearly double in years when the whitebark pine crop fails, and the whitebark pine itself is in trouble, say the authors. The pine crop is now failing almost every other year, and widespread suppression of fires has also been detrimental to its health. Global warming may also pose a threat to the tree species.
People also cause bear mortality in both direct and indirect ways, the researchers assert.
Whitebark pines are found at higher elevations that tend to be less used by humans. Simply being around more people increases their immediate chance of death. And by foraging closer to humans, grizzlies lose their natural wariness of people. Those bears will then have an increased risk of death forever, even in years with abundant pine seeds. They are seedless, flowerless and relatively small in stature, but a new study suggests that ferns can play an important role in determining the future composition of forests.