• Home
  • How We Work
  • Where We Work
  • News Room
  • About Us
  • My Nature Page

The Nature Conservancy in Africa - Conservation in Africa

The Nature Conservancy in Asia Pacific - Conservation in Asia-Pacific

The Nature Conservancy in the Caribbean - Conservation in the Caribbean

The Nature Conservancy in Central America - Conservation in Central America

The Nature Conservancy in North America - Conservation in North America

The Nature Conservancy in the United States - Conservation in the United States

The Nature Conservancy in South America - Conservation in South America

Mountain Maple Hollow



 Driftless Area
© Larry Stone

 

Closed to public

Mountain Maple Hollow contains several algific talus slopes and is extremely steep in places. It is home to rare and endangered species.

 

Locations

 

Finch Memorial Forest

 

Retz Memorial Forest

 

Roggman Boreal Slopes

 

Bluebell Hollow Preserve

This area has some of the highest quality algific talus slopes (also known as cold-air slopes) and is extremely steep in places. Northern monkshood plant, a federally threatened species, is found here.

Mountain Maple Hollow features an immense algific talus slope located along the Yellow River. There is a sparse canopy birch and balsam fir on the slope, and adjacent woodlands are dominated by oak and maple. Limestone cliffs occur on portions of the site. Rare species include golden saxifrage, northern wild monkshood, balsam fir, paper birch and a variety of landsnails.

Location
Allamakee County

Size
11.5 acres

Conditions
The upper corner of northeastern Iowa is like a window to the past. The earth’s underlying strata has literally been turned inside out by the glacial activity of prehistoric times. Bedrock, normally buried beneath glacial deposits hundreds of feet thick, dates back 600 to 400 million years. Cliffs and limestone escarpments, dolomite and sandstone are scattered with sinkholes, subterranean caverns and perennial groundwater springs. All this makes for a variety of microclimates that support diverse communities and species that were once thought extinct.

Why the Conservancy Selected This Site
Bluebell Hollow contains several algific talus slopes, a unique natural community that is home to many rare species in the Midwest. Small ice caves, where the core ice is believed to be more than 10,000 years old, are tucked away behind steep slopes of limestone scattered with loose (talus) rock, creating a unique feature called an algific (cold-producing) talus slope. During the spring and summer the air in the ice caves is colder than the outside air. Warm air drawn down into the sinkholes is cooled as it flows over ice, and then escapes through vents in the slopes keeping them at a temperature between 37 and 45 degrees Fahrenheit. In the winter, air in the ice caves is warmer than the outside air, reversing the airflow. As the warm air rises and exits through the sinkholes, the cold air is drawn through vents, freezing the ground water.

What the Conservancy Has Done/Is Doing
This preserve is being managed to protect populations of its many endangered species.