Moose Mystery

A species in trouble, and no one is sure why (beyond the probability that something we are doing is a proximate cause). And it seems to be an increasingly frequent phenomenon that mostly gets noticed when a large, charismatic species, like moose, is involved:

CHOTEAU, Mont. — Across North America — in places as far-flung as Montana and British Columbia, New Hampshire and Minnesota — moose populations are in steep decline. And no one is sure why.

Twenty years ago, Minnesota had two geographically separate moose populations. One of them has virtually disappeared since the 1990s, declining to fewer than 100 from 4,000.

The other population, in northeastern Minnesota, is dropping 25 percent a year and is now fewer than 3,000, down from 8,000. (The moose mortality rate used to be 8 percent to 12 percent a year.) As a result, wildlife officials have suspended all moose hunting.

Warm, wet weather, and ticks, appear to be involved. It’s a good example of how complex the web of life is and how the smallest things can set of a chain reaction that somehow ends up threatening a large, keystone species, like moose.