Freshwater Fragmentation Effects on Brown Trout By Rowena Humphrey October 19, 2006
Life History Two life-history tactics: Stay in “home” freshwater stream Migrate downstream to the sea Distribution Salmo trutta L.
Habitat
Dams
Consequences of Fragmentation Water Characteristics Mobility Vegetation Genetic Diversity Habitat Components
Water Characteristics Water level Depth Temperature Velocity Discharge Turbidity Substrate
Mobility Obstructions effect: Isolation of the watershed Accessibility of tributaries Migration Difficulty depending on water level, location, and structure.
Fish Ladders
Vegetation Dramatically shifting vegetation Fluctuation between high production and mortality for terrestrial and aquatic plants
Genetic Diversity Reproductive Isolation Within Watersheds Irregular Gene Flow
Genetic Diversity Reproductive Isolation Within Watersheds Irregular Gene Flow Decreased Diversity
Ineffective Single species Localized Individual obstructions Effective Multi-species Encompass all life-stages Movement Reconstruct the sequence and structure Conservation and Restoration
Ineffective Single species localized individual obstructions Effective Multi-species encompass all life-stages Movement reconstruct the sequence and structure Conservation and Restoration Temporary solutions Long-term solutions
Sustainability Initial design Materials of construction Physical characteristics of the water systems Appropriate monitoring and maintenance programs
Global effects on biodiversity
Questions?