Aquatic Plant Surveys

ABI routinely conducts aquatic plant surveys in order to design an effective management program specific to your water body, determine the types of aquatic plants growing there, their location and extent of growth. A survey involves systematically traveling around the waterbody and shoreline noting aquatic plant conditions. An important part of the survey is collecting samples of aquatic plants to verify the species. This is especially important if invasive, nonnative macrophytes are suspected to be present.

ABI generally conducts aquatic plant surveys during critical stages in the growth cycle of plants. Ideally, surveys are performed early in the growth season (spring), at mid-season (summer), and late in the growth season (fall). Nevertheless, this often cannot be done because of time and financial limitations. A survey at the height of the growth season (August), when plants are most obvious, provides a practical and valid alternative. An aquatic plant survey generally consists of:

1. Identifying major types of aquatic plants.
2. Drawing a map of aquatic plant types and locations in the water body.
3. Estimating relative abundance of aquatic plant types.
4. Collecting samples of plant species.
5. Identifying sediment types.

The relative abundance or prominence of the aquatic plant types often indicates how well the system is in balance. A healthy aquatic system usually has a variety of types and species of plants. The presence of only a few species of plants in a water body may occur where shoreline areas have been disturbed (by an influx of sediments or other contaminants) or have been invaded by exotic species.

Identifying aquatic plant species is important for several reasons.

1. Different species often respond differently to various control techniques
2. Determining which control methods to use
3. Determine the overall effectiviness of any control method during and after its implementation.
4. Identify any invasive, nonnative plant pests are present
5. Identify sensitive areas
6. Meet permit requirements

Aquatic Biologists, Inc is able to determine the best survey method to perform, whether it be an Aquatic Vegetation Assessment Sites survey (AVAS) or a Point Intercept survey. An AVAS survey samples the aquatic plant community throughout the littoral zone of the lake. The presence and density of a species is rated to describe its relative percent cover to other species, and sampling transects are marked using differential GPS technology.

A Point Intercept survey documents the overall species diversity throughout the lake on a grid of way points. Plants are identified at each sampling point and the dominant species is recorded to create a species distribution map. This large number of discrete observations creates a profile on lake-wide species abundance.