Barriers to Aquatic Organisms

1. Barriers to Aquatic Organisms By: Aaron Rice, Michael Tchen, and Leo Bertolino

2. Problem Statement Barriers to aquatic organisms have a detrimental effect on organism’s natural habitat range and fitness.

3. Goal/Purpose To establish a relative risk model for barriers to aquatic organisms including associated sources and habitats

4. Objectives • Establish connections rankings between sources and sub-stressors. • Establish significance rankings between sources and sub-stressors. • Establish connections rankings between sub-stressors and habitats. • Establish significance rankings between sub-stressors and habitats.

5. Sub-stressors • Terrestrial barriers • ex. roads • Aquatic barriers • ex. dams • Physical environmental changes as a barrier • ex. sedimentation

6. Aquatic Barriers • A barrier to movements of aquatic organisms that is found in the water.

7. Sources of Aquatic Barriers • Dams (2) • Migratory fish • Roads – Culverts (2) • Upstream travel • Marinas? (0) • Possible link - unsure

8. Effects of Aquatic Barriers on Habitats • Lake Champlain <6ft (1) • Fish specie loss • Lakes/Ponds (1) • Connected to rivers • Wetlands (1) • Connected to bodies of water • Forests (indirect?) (.5) • Bottom up effect? • Streams/Rivers (2) • Dams and culverts

9. Terrestrial Barriers • Land based barriers to aquatic organisms.

10. Sources of Terrestrial Barriers • Agriculture (.5) • Fragmentation of landscape • Urban (2) • Inhospitable passage • Roads (2) • Car traffic • Industrial (1) • Impassible

11. Effects of Terrestrial Barriers on Habitats • Lakes/Ponds (2) • Streams/Rivers (2) • Forests (1) • Herps add less to total biodiversity • Wetlands (2) • Effect due to loss of herpetofauna • Frogs, turtles, salamanders, etc.

12. Physical Environmental Changes as a Barrier • Changes to the hydrology and physical characteristics of water bodies causing a barrier to aquatic organism movement.

13. Sources of Physical Environmental Changes as a Barrier • Agriculture (1) • Urban (2) • Roads – culverts (1) • Increase stream flow • Waste water treatment plants (1) • Dams (2) • Industrial (1) • Increased water temperature • External (1) • Climate change ? • Increased runoff causing sedimentation and increase stream flow

14. Effects of Physical Environmental Changes as a Barrier on Habitats • Lake Champlain <6ft (1) • Decreased stream accessibility • Lake Champlain >6ft (.5) • Loss of fish • Lakes/ponds (1) • Loss of habitat and in turn species • Rivers/streams (2) • Loss of spawning habitat • Less upstream colonization • Wetlands (1) • sedimentation

15. Source – Sub-stressor Linkage Matrix

16. Source – Sub-stressor Significance Matrix

17. Sub-stressor – Habitat Linkage Matrix

18. Sub-stressor – Habitat Significance Matrix

19. Total Ranking System • Weighted average • Multiply the linkage matrix by the significance matrix. • Terrestrial and Aquatic Barriers weight 2x physical environmental barriers. • The weighted totals on the significance matrices are pre- linkage adjustment.

20. Recommendations for Dams • Provide large economic benefits • Fish ladders around larger dams (questionable effectiveness) • Careful removal of old dams • One large dam will prevent all upstream travel

21. Recommendations for Culverts • Identify Causeways using GIS • Modify road culverts- sediment substrate, allow light • Add temporary drift fence to culvert • Establish 289m core habitat and 50m buffer zone (Semlitsch and Bodie 2003)

22. Recommendations for Culverts cont. • Culverts- site by site • No long culverts-more chance to not passs through and cuts off bends • Undersized culverts-hourglass syndrome • Take into consideration Vertical adjustment range (VAR)

23. Physical Environmental Changes • Plant buffer crops along rivers and streams • Increase culvert sizes to reduce flow speed • Better management of waste water • Reduce impassible dams which impede water flow • Decrease urban impervious surface • Permeable pavement • Natural sinks for storm water drainage

24. Questions?