30 ACRES OF NATURE PRESERVE

Meadows in Georgia are often referred to as prairies. These areas are dominated by grasses and herbaceous plants such as wildflowers. Most of the plant and animal species found in prairies are specially-adapted for fire, which prevents larger shrubs and trees from becoming established. Prairies which are not fire-maintained undergo succession: the area is colonized by subsequently larger species of grasses, herbs, shrubs, and eventually trees. Prairies are also home to a diverse animal community which includes smaller mammals, deer, and a wide range of nectar and seed-eating insects and birds–many of which are pollinators.

Fire is one of the most important disturbances in Southern ecosystems. In pre-colonial Georgia, prairies and savannahs were managed by lightning strikes and Native American controlled burns. As European settlers arrived and forests were replaced by fields, meadows sprang up in fallow fields and clear-cut land but eventually returned to forests.

Established forests have 3-4 layers. Low herbaceous plants and shrubs can be found in the forest floor, smaller, shade-tolerant trees and vines in the understory, and the tallest trees make up the canopy and emergent layer. When a canopy tree is knocked down it leaves a gap which allows sunlight to reach the forest floor and creates a new, tiny community within the forest. This allows specially-adapted, fast-growing tree species to reach the canopy.

In the Georgia Outer Piedmont region (from the Chattahoochee River to the fall-line) forests are typically dominated by oak, pine, and hickory species. Georgia forests are home to more species of oak and trillium than anywhere in the US. One species, the Georgia oak (Quercus georgiana), is an endangered species that only grows near rock outcrops such as Stone Mountain and Arabia Mountain.

Blue Heron Nature Preserve’s forest ecosystems are directly adjacent to creeks. The sandy sediments deposited by Nancy Creek allow pine trees to dominate the bottomland, while tulip poplar can be found on the north side near the community garden. Along the steep banks near the parking lot trail entrance, a colony of chipmunks can be found darting in and out of underground burrows amongst the tree roots.

A wetland is an area of land that is covered by water for part of the year. The soils in a wetland primarily contain clay, which create a water-resistant layer, and decomposing plant matter, which gives them their characteristic smell. Wetlands are sometimes called an ecotone–a place where two different ecosystems meet and overlap.

Ecotones bring the best of both ecosystems to create a new ecosystem high in biodiversity. Wetlands are especially important as borders between aquatic (water) and terrestrial (land) ecosystems and are some of the most diverse habitats on Earth.

In urban areas, wetlands are especially important for their ability to recharge aquifers, control storm surges, and catch flood water; they even help improve water quality using bacteria naturally found in the soils.

The term “riparian” refers to rivers, creeks, streams, and their surrounding floodplains. Sandbars and floodplains are areas of high geomorphic activity, meaning there is constant movement of rock, sand, and silt from outer banks and deposition of these sediments along inner banks and floodplains.

New sediment deposits create areas of primary succession for specially-adapted “pioneer” plant species to thrive, but many other species of tree cannot become established. These pioneer species help keep some sediment in place and build up the stream banks.

Many species of fish, amphibians, reptiles, and mammals live in riparian streams and rivers, creating a diverse system of predators and prey known as a food web. At the base of a riparian food web lies algae and water plants, known collectively as primary producers. The producer species provide food for herbivores, also known as primary consumers.

The primary consumers are, in turn, eaten by predators which make up the secondary and tertiary consumer level. When one part of the food web is negatively affected by humans or a natural disaster, all levels of the food web may be thrown out of balance.