Barriers to Aquatic Organisms

By: Aaron Rice, Michael Tchen, and Leo Bertolino

Problem Statement

Barriers to aquatic

organisms have a detrimental

effect on organism’s

natural habitat range and

fitness.

Goal/Purpose

To establish a relative risk model for barriers to aquatic organisms including associated sources and habitats

Objectives

1. Establish connections rankings between sources and sub-stressors.

2. Establish significance rankings between sources and sub-stressors.

3. Establish connections rankings between sub-stressors and habitats.

4. Establish significance rankings between sub-stressors and habitats.

Sub-stressors

Terrestrial barriersex. roads

Aquatic barriersex. dams

Physical environmental changes as a barrier

ex. sedimentation

Aquatic BarriersA barrier to movements of aquatic organisms that is found in the water.

Sources of Aquatic Barriers

Dams (2)Migratory fish

Roads – Culverts (2)Upstream travel

Marinas? (0)Possible link - unsure

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

Terrestrial Barriers

Land based barriers to aquatic organisms.

Sources of Terrestrial Barriers

Agriculture (.5)Fragmentation of landscape

Urban (2)Inhospitable passage

Roads (2)Car traffic

Industrial (1)Impassible

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.

Physical Environmental Changes as a Barrier

Changes to the hydrology and physical characteristics of water bodies causing a barrier to aquatic organism movement.

Sources of Physical Environmental Changes

as a BarrierAgriculture (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 ?

o Increased runoff causing sedimentation and increase stream flow

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

Source – Sub-stressor Linkage Matrix

Agriculture

Urban

WTP

Roads

Dams

Fisheries

Marinas

Forested Area

Industrial

Parks

External

Aquatic Barriers

0 0 0 1 1 0 .5 0 0 0 0

Terrestrial barriers

1 1 0 1 0 0 0 0 1 0 0

Physical environmental changes

1 1 1 1 1 0 .5 0 1 0 1

Source – Sub-stressor Significance Matrix Agriculture

Urban

WTP

Roads

Dams

Fisheries

Marinas

Forested Area

Industrial

Parks

External

Aquatic Barriers

0 0 0 2 2 0 0 0 0 0 0

Terrestrial barriers

.5 1 0 2 0 0 0 0 1 0 0

Physical environmental changes

1 2 1 1 2 0 0 0 1 0 1

Weighted Total

.4 .8 .2 1.8 1.2 0 0 0 .6 0 .2

Sub-stressor – Habitat Linkage Matrix

LC <6

LC >6

Lakes/ ponds

Rivers/ Streams

Developed

Forest

Herbaceous

Agriculture

Wetlands

Aquatic Barriers

.5 0 1 1 0 .5 0 0 1

Terrestrial barriers

0 0 1 1 0 1 0 0 1

Physical environmental changes

1 1 1 1 0 0 0 0 1

Sub-stressor – Habitat Significance Matrix

LC <6

LC >6

Lakes/ ponds

Rivers/ Streams

Developed

Forest

Herbaceous

Agriculture

Wetlands

Aquatic Barriers

1 0 1 2 0 .5 0 0 1

Terrestrial Barriers

0 0 2 2 0 1 0 0 2

Physical environmental changes

1 .5 1 2 0 0 0 0 1

Weighted Total

.6 .1 1.4 2 0 .6 0 0 1.4

Total Ranking System

Weighted averageMultiply 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.

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

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)

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)

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

Questions?