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13 Cards in this Set
- Front
- Back
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Why is understanding habitat important? |
- many habitat issues affect fish populations - urbanization have been a big problem with habitat destruction |
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Fish can lose habitat when: |
- it dries up at innappropriate times - it fills with sediment - it is choked with vegetation or filled with debris - it is contaminated with toxicants - it becomes unlivable due to eutrophication or deoxygenation - it is destroyed through structural damage |
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Major causes of declines of Native Fish Species (4 reasons) |
1. Physical habitat alteration 2. Introduced/ invasive species 3. chemical alteration contamination or pollution of water (including nutrients) 4. overharvesting (over exploitation) |
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Habitat Issues (5 main aquatic habitats suffering) |
1. Lakes 2. Rivers and Streams 3. Riparian zones 4. Eustuaries 5. Marine Environments |
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Habitat Issues : Lakes |
- deforestation of lake basins raises temperature turbidity and organic input - draining and filling of marshes and isolation of wetlands can be important for maintaining temperatures -blockage of streams and tributaries |
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Habitat Issues : Rivers and streams |
- deforestation of basin - heavy logging in streams causes increase in stream temperatures - increased sediment can destroy spawning areas for many species - channelization : removing natural bend in streams (removes deep pools where fish can wait for food) - road construction (sediment gets into stream) - dams affect flows and water temps - extremely high water temps can can kill fish |
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riparian zone definition ? |
terrestrial borders immediately adjacent to rivers and streams |
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Ecological functions of riparian buffer zones |
reduce channel erosion - process nutrients and contaminents - control the range and elevation of stream temperatures |
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habitat fragmentation definition |
when a species strays away from its preferred environment, causing population fragmentation |
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Habitat Issues: Estuaries |
watershed development has increased silt load, nutrients and contaminants - dredging of channels is also an important issue in estuaries (San Franciso Bay and Fraser River estuary pick up silt and contaminants) |
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Habitat Issues : Marine Environments |
- bottom trawling is most important habitat issue in marine environments |
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Solutions to these habitat issues |
- marine protected environments - dam removal - stream restoration |
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Current state of habitat issues? |
- much damage is of the past, now we are in a restoration phase - science will be key to fix this - it will take a long time see benefits - time is always an issue |
