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Notes 3

20.11.2013 17:05:00
Templates and Ecological Interactions
-helpful for managing stream ecosystems
Watersheds, Networks, Stream Hydrology
Channel formation and stream habitat
Chemical environment
Ecological interactions/biotic interactions
Indicators of Hydrologic Alteration
-magnitude of monthly water conditions
-magnitude and duration of extreme conditions
-timing of extreme conditions
-frequency and duration of increased and decreased pulses
Overflow components
-monthly low flows
-extreme low flows
-high flow pulses
-small floods
-large floods
Rivers with increased populations = increased ammonium b/c sewer
treatment chemical indices for stream assessments
(also nitrates and phosphorous)
Biotic indicies for stream assessment
=% contribution of dominant family
=EPI index
=FBI index
20.11.2013 17:05:00
Nonindigenous species in fluvial environments
Nonindigenous = not native in a particular area
Four types:
-localized and numerically rare
-widespread but rare
-localized but dominant
-widespread and dominant
‘ecological imperialism’ (people recreate new landscapes, ex. Westward
expansion, to be similar to where they came from, think their flora and
fauna is better)
Examples with rainbow/brown trout affecting stream dynamics (see slides)
-Zebra mussels example
-Saltceder tamarix
-native vegetation contributes less to allochthonous inputs than
River Fisheries
11/20/2013 5:05:00 PM
What maintains productivity and biodiversity in rivers?
Floodplain Rivers:
 Amazon River near Manaus
 High level of complexity
o Low water: water in main channel, oxbow lakes, depression
o High water: flat water across smaller channels
 Hudson River: Floodplain reduced
o Backwater areas greatly reduced since 1907
 Constrained river
o Reduce size of channels in anthropogenic areas
 Mississippi River near St. Louis
o Huge flood event in 1993
o Reclaimed floodplains
Flood-Pulse Concept
 Annual predictable pulse (flood) is major control on riverine
structure and function
o Not the typical idea that production comes from upstream,
predictable change as it moves downstream
Lateral exchanges between floodplain and main river channel that
gives nutrients
Pulses result in alteration of flooding and drainage of floodplain
(aquatic/terrestrial transition zone)
Most primary production in floodplain rather than main channel
o Input of sediments from floodwaters; nutrient release from
newly flooded soil
 Spurs spawning
o Large input of biomass of aquatic vegetation
 Young and adult fish disperse and feed, dissolved O2
o Consolidation of sediments; moist soil germination
 Regrowth of terrestrial vegetation after water recedes
Fish Reproduction in Floodplain Habitats: FPC flood pulse concept –
alternative to river continuum concept (focuses more on the floodplain,
disconnected from concept of movement of nutrients downstream)
Temperal degree overlap between warm T and flood
o Flood coming in in warm T in temperate environments
o High PP in this time of year
Predictability of flood
o Fish need to be able to time to the flood pulse to spawn in the
right time
Rate of rise and fall
o Slower is easier for fish to move with it
Duration of inundation
o Need a longer time of flood for fish to spawn and have a life
history strategy
Area of floodplain
o Larger floodplain=more habitats available for fish
Key Life History Attributes (fish population factors)
 Reproduction
 Growth
o Need food sources and organic material
 Survival
o What are the sources of mortality?
Small river spawning habitats: brook trout – North temperate habitat
 Use small rivers to spawn in reds
 Use upwelling ground water
o Deposit in late fall, eggs covered by ice in winter
 Avoid predators during spawning season
o Upwelling groundwater removes ammonia and waste and
fungi accumulating on eggs
o Provides constant T
Vegetation associated spawning: pirate perch
 Spring spawner
 Attach eggs to tree roots and vegetative banks
o Adhesive eggs
o Hide eggs away from predators
Channel catfish – South or tropics
Spawn in cavity formed by rocks, logs, or a hole in a lake or river
Migrate to ocean or remain in coastal system? – Swedish stream
 How to accumulate enough E to grow large enough to allocate
energy to reproduction?
 Life history challenge: get enough E to reproduce
 Fish in small steams need to decide to go to ocean or larger river
system with more nutrients but more predation
Migratory and resident populations in coastal streams: costs of migration
 Migratory brown trout pops found closer to coast and at lower
altitude than year-round resident ones
o Less energy to migrate if you’re closer to the ocean coast
o Less time in low energy environment
o Migratory fish spend several years in ocean environment
 Recruitment of migratory brown trout pops declines at higher
altitudes, but not resident ones
o Migratory fish increase recruitment at locations
Banded kokopu
 Strong altitudinal pattern at watershed scale
 Reflecting:
o Migratory access
o Habitat type – forest cover
Migratory Life Cycles
 Diadromous: move between fresh and saltwater to complete lifecycle
o Anadromous: sea fish that reproduce in freshwater (salmon)
o Catadromous: freshwater fish that breed in the sea (eels)
American Shad: Alosa sapidissima
 Shade CatchPerUE: Delaware River
o Low catches per haul up until a spike in 1965
o Management to increase shad fisheries
 Reduction in fish harvest
 Then rise in 70s and 80s
 Fry stocking
 Improve fish passage
Present decline from 90s
Belief is that ocean conditions increased shad, not the actual
river qualities
coast American shad management
Harvest regulations
Fry stocking
Fish passage enhancement
o Recognition (through no management) of ocean condition
Hypothesis: Physical stream environment determines ecological effect of
 Lots of wood debris and forested area on one side of the stream
 Open and larger sediment in open watershed
 Gradient between heavy and light timber harvest
o Retention of fish carcasses increases with large wood volume
 Retains nutrients of stream
 Before salmon migrate into stream channels, you have
more PP (chlorophyll) in heavily harvested watershed
(more nutrients from landscape and light)
 After salmon enter in fall, opposite effects (less PP in
streams with heavily harvested watershed) because
they are stirring up the sediment and decreasing light
River Use and Dams
11/20/2013 5:05:00 PM
Cautionary Fish Tale
 Colorado Pike
o Really aggressive fish peopled liked to fish
o Large fish by 1967 that they were endangered
o Top predator that died
o Changed river to use water
American Experiment
 Population expansion in relation to hydro-geomorphic character of
ricer basins encountered
As population expanded west, encountered lots of rivers
o Rivers used for mills and use
 In Ohio: Flood plains
 In arid parts west: irrigation
 Pacific NW: power
 Locks, levies, dams used to interact with water
How much water does a river need?
 Varies
 Thinking about stuff that lives in rivers
 As variation increases, river health declines
Simplified contrast
 Rivers want to change flow through time
 Humans want rivers to not change through time
Dams and Demands
 Off land factors: fields, cities
 Most prominent in-channel mechanism for flow alteration
 Golden age of dams
 Many reasons to build dams, mostly recreation
o Many small dams out there
o Bigger dams used for hydropower, irrigation, flood control
Effects can be dramatic
o Before dam, Green River: driven by snowmelt
 Snows in winter, runs off in spring, low flow in summer
o After dam:
 Far fewer flood peaks, higher flows in summer
 Make sure water is always available
Disrupts millennia of evolution
Dam Impacts
 General Findings: some consistency despite regional differences
o High magnitude decreased
o Low magnitude increased
o Daily magnitude variance decreased
o But reversals and pulse count increased
o Timing expanded, seasoning is off
Flow Homogenization
 Regional scale differences in 1st half of 20th century were reduced in
dammed rivers but retained in undammed rivers
Global Issue
 Info on 292 large river systems
 Are the systems modified? (Fragmentation and storage capacity)
o Much of the world is red where people live
o Outside of remote systems, not many unaltered major
o Productivity is higher for rivers with infrastructure (dams)
 Reservoirs
16.5 million dams globally
o 8000 cubic kilometers
Latin America
 47% projects are high impact
Flow-Ecology Relations
 Effects biota through:
o Habitat - space
o Evolved life history patterns
o Connectivity – movement place to place
Riparian Flow Ecology (out of channel)
 Variety of different pathways from infrastructure to diversity
o Get down to loss of adapted species or change in succession
(natural cycle)
An Option
 Help organisms out
o Blow up dams
Environmental Flows
o Want infrastructure and productivity, but also want species to
o Quantity and quality and timing of water needed to sustain
aquatic ecosystems and services they contribute to human
 In-between natural and regulated
Blue box: river biology and dynamics
Red box: what people who live in watershed want
Green box: river science meets biology
o Adaptive adjustments!
Stream and River Restoration
11/20/2013 5:05:00 PM
 Not until early 1970s that legislation or stream restoration really
o Nepa, clean water act, endangered species act
o Army corp undone under legislation
 More projects to restore streams than any other ecosystem besides
maybe wetlands
 Functions people wanted from streams were taken away by army
corp engineers, so lots of stream restoration
Categories of fluvial modification
 Channelization
o Flood control act straightened stream channels
 Levees
o Disconnect stream channel from flood plain
 Dams
o Retain water, reservoirs
 Removal of riparian vegetation
o Common in agricultural areas
Invasive species
Impermeable surfaces in watershed
Chemical discharge
o Sewage treatment plants
o Nutrient runoff
o Smaller diversions from landform modification
Pipes (streams going underground)
Construction on floodplains
Synthesis of US river restoration efforts
 37000 river restoration projects reviewed
 most costly: land acquisition
 least costly: riparian management
 cumulative: 9.1 billion dollars
o projects were not evaluated afterwards for success
 least expensive projects were most used
Regional US river restoration efforts
 Upper Midwest: number of water quality and riparian management
much reduced than other areas
 Pacific nw: very few bank stabilization projects because less of an
agricultural region and highly erodible soils
Restoration: return to original undisturbed state
o Use a temporal/historic or another stream to restore to that
o Few projects really try to fully restore streams
Rehabilitation: restore or improve some aspects of a stream
Habitat enhancement: localized (eg fish structures)
Reclamation: return a stream reach to its previous habitat type, but
not restore all functions (eg levee removal)
Mitigation: compensate elsewhere for adverse effects
Common Rehabilitation
 Road rehabilitation
o Redwood national park
 Park was to see if place could be restored
o Recreate connectivity for fish
o Rehabilitation meant removing road and restoring landscape
and vegetation in high erodible soils
 Riparian Rehabilitation: silviculture
o Restore vegetation
o Remove invasives and reestablish vegetation due to grazing
or human disturbance
Fencing and Grazing
o Fence out animals from grazing
Floodplain rehab
o Connecting isolated habitats
o Levee breaching
o Channel reconstruction
o Creation of new floodplain habitat
 Removing berms
o Channelizing/Restoring Kissimmee River
 Cost $414 million
Dam removals
o 1990s very few
o 2000s more and more
o downsides: nutrients or contaminants in sediments
In stream habitat structures for fisheries enhancement
Log structures
Log jams (multiple logs)
Cover structures
Boulder structures
Brush bundles
In stream channel modification
 Rosgen
The Future of Running Waters
11/20/2013 5:05:00 PM
Identifying Key Drivers
 Humans are everywhere
o There are not many pristine ecosystems that haven’t been
impacted by human influence
o Ecologists: How to manage and sustain systems
 Need to improve ecosystems
 Ambiguous metrics – not like human health with good
What do we need to do?
Understand ecosystem drivers
Understand large-scale patterns
Understand long-term trends
Understand ecosystem drivers
Anthropogenic biomes – Erle Ellis
 Working in world with anthropogenic biomes, not classic biomes
 Humans control biodiversity and ecosystem processes as much as
Classic biome maps do not represent state of environment
o Much of biome area does not exist (potential vegetation)
o Limited mention of urban and agriculture land use
Classic climate based biomes are not static
o Anthropogenic climate change is altering biome location and
Biomes derived from global patterns of human interactions
Key Drivers
 Exploitation of biological resources
 Land use modification
 Alteration of biogeochemical cycles
 Alteration of physical processes
 Human influences on the movement and distribution of living
 Aggregation and accumulation of unique or rare compounds
Are key drivers anthropogenic?
 Chart of % of sediment from cultivated land
o Used cesium 137 tht was deposited on landscape from
nuclear testing in 1950s and 60s
o Sediments from clay glacier deposits have lower levels of
Ce137 than sediments from agricultural lands
Movement of Earth per Year – human driver
 Under natural conditions, most of earth moved by rivers is in west
o Young mountains
o Steep erodible landscapes
o Not much in eastern US
Current earth movement by mining, construction, etc
o See the opposite of earth movement
o Effects landscape greatly
Hydrological Changes in Arizona – human driver
 Blue lines are natural rivers before development
Turquoise lines: contour to parallel lines are canals
o Now irrigation and ground water pumping
o Summer time now has standing water and vegetation where
ephemeral streams used to be
Nitrogen cycling in urbanized desert ecosystem
o Sycamore Creek (undisturbed): short flow paths in landscape,
hyporheiic exchange, nitrogen cycling short
o Indian bend wash (urbanized): Nitrogen cycling under control
of humans: long flow paths – deep waters that are pumped
back up
 Fertilizers, deep waters pumped up
Understand large-scale patterns
Compared forested to non forested stream reach across many stream orders
 Forested wider than unforested streams
 Unforested had higher water velocity
Forested = rougher, more ammonium uptake, respiration, total
Understand long-term trends
Mississippi river sediment discharge
 Sediment discharge is currently correlated to water discharge
 In early decades, succeeded the water discharge
Increased river alkalinization
 Upward trend in many eastern states
Increase in elevation and precipitation had positive relationship with
What is a stream and why does it mater?
 Legislation
Defining “waters of the US” is a matter of current political and constitutional