"If temperatures rise, the species that are limited by winter lows will be able to move north rapidly," she said.

Forestville has summer highs in the 80's (with cooler nights) and winter lows in the 40's.

The population grows from a winter low of about 250 to 300 to a summer high of 8000 or more.

Temperatures shift from characteristic summer highs in the day and drop to winter lows at night.

Very rarely do winter lows go below 25 degrees.

Summers can bring daytime temperatures that climb into the 90s Fahrenheit, and winter lows can be well below zero.

Nor does it thrive where winter lows remain above 15 degrees.

It is said to have taken winter lows of 19 F (-7 C), and might even handle colder temperatures.

The average winter low is 8 C (48 F), with temperatures falling below the freezing point up to ten days per year.

Average summer high upper 70s to around 80F and average winter lows of 45F daytime and 34F night.