Wetland Terms – G-H
- garbage: waste material that is wet, such as recent yard and food waste.
- garbology: the study of garbage.
- garlic mustard: Alliaria petiolata; an exotic invasive plant, originally from Europe, that grows at the wood's edge.
- gilled snail: an aquatic macroinvertebrate of the class Gastropoda; enclosed within one shell; sensitive to pollution.
- global positioning system (GPS): a satellite-based radio-navigation system developed and operated by the U.S. Department of Defense. GPS permits land-, sea-, and air-based users to determine their 3-dimensional position, velocity, and time, 24 hours a day, in all weather conditions, anywhere in the world.
- grassland: a biome in which grasses are the major species (e.g., steppe, prairie, savanna).
- gravel: suspended sediment or bed material with a particle-size of 2.0-64.0 mm in diameter.
- great blue heron: Ardea herodias; a long-legged bird with a sharp beak used to catch aquatic animals. It has a bluish gray body, reddish brown neck, and often white splotches near its eyes; lives near and in lakes, ponds, and marshes.
- ground water: water that flows or seeps downward and saturates soil or rock, supplying springs and wells; also water stored underground in rock crevices and in the pores of geologic materials that make up the Earth's crust.
- habitat: the type of environment in which an organism usually lives.
- harvesting: the process of gathering a crop.
- hellgrammite: an aquatic macroinvertebrate of the order Megaloptera; also called dobsonfly. Larvae have three pairs of segmented legs and four terminal hooks on their abdomen; sensitive to pollution.
- herbicide: a toxic substance used to destroy plants.
- herbivore: an organism that eats only plants; a primary consumer.
- humus: decayed remains of organisms. The addition of humus to soil enriches it with organic material and increases the capacity of the soil to hold air and water.
- hydrilla: submerged aquatic vegetation (SAV), Hydrilla verticillata; non-native invasive plant with branched stems up to 25 feet long; found in all types of water bodies.
- hypothesis: a possible, testable explanation, based on an educated guess and previous observations; a proposed solution to a scientific problem.