Presentation on theme: "Aquatic Plant Management Louis Helfrich, Ph.D. Department of Fisheries & Wildlife Sciences Virginia Tech."— Presentation transcript:
Aquatic Plant Management Louis Helfrich, Ph.D. Department of Fisheries & Wildlife Sciences Virginia Tech
Plants: Problem or Benefit? Photosynthesis by aquatic plants, both algae and rooted water plants, represents the major source - contributing from 70 to 90% of the dissolved oxygen. Aquatic plants can trap excessive nutrients and detoxify chemicals. Aquatic wildflowers such as the water lily are sold and planted to provide floral beauty in water gardens.
Plants serve as nursery habitat and the foundation of the aquatic food chain. They provide food, dissolved oxygen, and spawning and nesting habitat for fish and waterfowl. Wildlife Food Nursery Shelter Critical habitat
Too many plants! A weed is simply a very successful competitor for space, light, and nutrients. Restricted recreation Fish kills Fish flavor problems Pond water odor problems Drinking water taste problem Stunted fish growth
http://aquat1.ifas.ufl.edu/welcome.html http://www.ext.vt.edu/pubs/fisheries/420-251/420-251.html Control Methods For Aquatic Plants in Ponds and Lakes Authors: L. A. Helfrich, R.J. Neves, G. Libey, and T. Newcomb, Extension Specialists, Fisheries and Wildlife Sciences, Virginia Tech Publication Number 420-251, posted March 2000
The density of aquatic plants (both algae and rooted macrophytes) is largely a function of (1) nutrient concentrations (phosphorous and nitrogen) and, (2) light. In general, nutrient-rich, shallow lakes experience greater nuisance water weed problems than nutrient-poor, deep lakes.
Water Plant Control http://www.ext.vt.edu/pubs/fisheries/420-251/420-251.html Watershed management Physical Biological Chemical –Water dyes –Barley straw
Aquatic plants can be divided into (1) algae and, (2) rooted water plants. Algae are primitive, simple plants which lack true roots, leaves, or flowers and reproduce by spores, cell division, and fragmentation. They range in form from unicellular (single cells), through colonial and filamentous types, to advanced forms which resemble the higher aquatic plants. Some are microscopic, but impart green color to the water, others are visible as surface films or bottom dwelling forms which are often confused with higher aquatic plants.
High Diversity of Aquatic Plant Species Pondweeds, Potamogeton spp.
Barley Straw? The rate is 2-50 grams/square meter 1 acre pond = 4046 m2 of water Therefore, treatment of 1 acre pond at the lowest recommended dose, 2 grams would require 8092 grams or 17.8 pounds of straw. Source: Aquatic Ecosystems 1- 877-347-4788. They charge $55.00 for 11 pounds of barley straw. Minimum treatment for 1-acre pond costs $110/acre.