For this lab, the class took a trip to the Ocmulgee National Monument in Macon, GA. For the first half of the lab, we went on a nature hike to view and discuss a creek bank. Along the way, we found a baby turtle. (I heard group two saw a snake! Yikes!) For the second part of this lab, we viewed the Indian Mounds.
What is Leaf Litter?
Leaf litter is dead plant material, including leaves, plant needles, twigs, and bark, that have fallen down to the ground from trees and plants. This forms an extra layer of earth on top of the pre-existing layers of soil, providing a habitat for many small animals, fungi, bacteria, and plants. As this litter decomposes, nutrients are released into the ecosystem. The portion of litter that is not readily decomposable is known as humus.
Decomposition of Leaf Litter
The decomposition of leaf litter is a major source of nutrients for terrestrial ecosystems. Insects and microbial decomposers break down the leaves, releasing organic nutrients into the soil for the plants to use. This occurs because bacteria are able to convert the dead, organic matter into simpler compounds usable for and by the soil. The rate of decomposition is affected by two primary factors: temperature and soil moisture. In general, the higher the temperature, the faster decomposition rate. That is, for every 10 degrees of temperature of temperature increase, the rate increases by a factor of 2. Soil moisture is not as concrete. Very dry soils inhibit decomposition because they cause the bacteria and other microbial decomposers to dry out. Moreover, very moist soils engender anaerobic conditions, which are less efficient at decomposing materials compared to aerobic conditions. Soils of intermediate moisture are best, hence the ambiguity.
Why Leaf Litter is Important
- Home to many species
- The food chain starts with small soil and leaf litter organisms
- Help decompose organic matter
- Protects the underlying soil from erosion
- Aids in moisture retention
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