Ojibwe Lifeway: Respecting Our Culture (“biboon”-winter)

Wisconsin is projected to warm by 4-5°F by the middle of this century. Northern Wisconsin is projected to warm the most. What is the potential impact of these changes on the American marten?

CLUE:

Rising summer temperatures means more than just hot weather. Higher temperatures mean greater loss of soil moisture through evaporation and evapotranspiration . This creates drought conditions, increased chance of fire, and greater pest outbreaks.

Forest habitats preferred by martens are characterized by trees and plant species adapted to cool temperatures, moist soils and low evapotranspiration .

A warming climate also means changes in the growing season. As trees will need more moisture from the soil for a longer amount of time, the amount of water they use through evapotranspiration will increase. This will reduce the amount of moisture available in the soil. A longer growing season will benefit some tree species and encourage new tree species to establish themselves. Other trees not adapted to higher temperatures and less soil moisture may suffer die-back or may die. Tree species, already at the southern edge of their range , may eventually disappear.

The USDA Forest Service has identified Wisconsin tree species that are projected to suffer declines due to climate change. These include tree species that provide American marten habitat, including balsam fir, white cedar, yellow birch, sugar maple, hemlock, and white spruce. Open this pdf to see this research.

Compare the change in nights below 32-degrees that have historically occurred and what are projected by mid-century. While winter precipitation is expected to increase, warming winter temperatures above 32-degrees F, can cause precipitation to fall as freezing rain rather than snow.  How could this affect American marten who rely on deep snow for habitat and cover? (photo credit: University of MN-Duluth)

CLUE:  

Reduced snow cover could threaten wildlife, like the American Marten, that depend on snow cover for winter survival. Climate projections indicate that snow cover will drop by about 40% in northern Wisconsin over the next 50 years. Some species, like the American marten, rely on areas under the snow for insulation from cold winter temperatures. In areas where they co-exist with fishers, changes in the amount and composition of the snowpack could put martens at a competitive disadvantage.

Wisconsin is projected to be wetter (map on the left) in the future. However, climate models project a trend toward less rain in summer growing season (map on the right). What is the potential impact of these changes on the American marten?

CLUE:

Precipitation amounts can affect the sustainability of tree species, like hemlock, spruce, and yellow birch that prefer moist soils. Dry summer growing conditions can stress trees making them susceptible to pest infestations and fire. These trees provide the critical habitat features needed by the American marten.

By 2060, the frequency of very hot 90-degree days in northern Wisconsin is expected to increase from the 5 days per year currently experienced to 20+ days per year.  Greater increases are projected across Wisconsin. What is the potential impact of these changes on the American marten?

CLUE:

Increases in the length and severity of late summer droughts will have the most widespread effects on tree species. This will affect ecosystems and habitats that support wildlife.

Drought is closely linked to temperature and rainfall amounts. While northern Wisconsin is expected to have more heavy rainfall events, little change in the total amount of summer rain is predicted, but temperatures will be much warmer. Climate models suggest more frequent, localized periods of extreme drought which will dry up forest soils. Trees that require moist soils, like many that comprise the forest type used by martens, could struggle to survive under drought conditions.

Stressed trees are also more susceptible to attacks from pests and disease. As susceptible trees die, greater amounts of deadwood will accumulate. Although American marten prefer habitats with lots of woody debris on the forest floor, higher temperatures and drier conditions would increase the risk of forest fires in these areas which could destroy their habitat.