Quiz 3 Flashcards
what exerts a force on sediments and what determines magnitude of force
water exerts the force
magnitude is determined by water velocity and sediment size
how do rivers sort sediments
sediments will be deposited in areas with low water velocities and be transported away from areas with faster water velocities
how do patterns of erosion and deposition differ across spatial scales
local: local habitat features like woody debris or rocks alter water velocities and causes differing patterns of erosion and deposition of sediment on small scales
reach: river meanders will elf organize with the patterns of deposition and erosion on the inside and outside of curves
whole river: over thousands of years water will erode mountains and create valley, this sediment will be transported downstream until water velocities slow and then sediment is deposited
what does deposition/transportation of sediment downstream do
decreases slope of lower reaches which further decreases water velocity
how do rivers generally evolve to be like
steep and erosive headwaters
less steep, and where sediment is deposited in lower reaches
what is the role in erosion/deposition different parts of rivers do
headwaters : production
middley bit: transport and storage
lower reaches: deposition and storage
how does the seasonal patterns of water flows effect rivers
rivers are constantly shifting the distribution of river habitats
what is happening to floodplain rivers constantly
they are shifting habitat mosaic
what do different river habitats have
different water velocities, temperatures, and sediment sizes
what do different habitat types support
different types of life stages in species and a diversity of species
what are the four C’s that make a good salmon habitat
cold
clean
connected
complex
what may limit species like salmon with complex life stages
a specific life stage or habitat may limit the overall production of the population
what does a high reproductive capacity and a density dependence mean
high compensatory capacity
what is the stock- recruitment relationship
the relationship between the # of parents and the # of offspring they produce to the next generation
what are the Beaverton-holt and the Ricker relationships
2 common stock-recruit relationships used to describe the density dependent relationship in fish populations like salmon
what is general idea of Ricker model
at some point more individuals is bad for species
what is benefit of beaverton-holt and Ricker
B-T: follows reality more
R: easier for math and models
are beaverton-holt and Ricker models that realistic
no
what defines the maximum sustainable fish yield (MSY)
stock-recruit relationship
what is the MSY
maximum sustainable yield
max # fish you can harvest indefinitely
what else controls slalom abundance other than harvest
ocean climate
river conditions (temp and hydrology)
competition with pink salmon
freshwater habitat
how do different salmon populations differ
different life histories and adaptations
different exposure to stressors
what’s one way fisheries can be more stable
if the integrate across salmon diversity
what is a riparian
terrestrial area next to body of water
what one: conifers or deciduous, are low/high quality food
conifers: low
deciduous: high
where do stream salmonoids derive most of their energy from
terrestrial invertebrates that have fallen in
what do fishes reaches do
provide food downstream
what is habitat coupling
connection between 2 adjacent habitats
how does riparian loss (logging ) affect temperature and as a result salmon
increases stream temp by 1-4 degrees C
this could benefit salmon (short term) and harm them
how to trees influence hydrology
their roots overland water flows and they transpire water
how does summer influence water flow
initially summer flows go up (good for fish) but then synchronized tree growth will decrease it (bad for fish)
what does logging cause
flashier flows
how do riparian plants influence sediment erosion
decrease it
how does logging influence fine sediment outputs and how does this affect salmon
increases it
smothers the eggs
how can sediment affect stream form
increased sediment can change stream form
what do large woody debris do
provide habitats for fish
flow refuges
traps sediment and organic matter
how does large woody debris end up in rivers
deposited by in fall and then buried and transported over time
what one: conifer and deciduous, degrade slow/rapidly
confier : slow
deciduous: rapid
what is riparian logging management now informed by
understanding how riparians affect streams
what are the different types of streams (riparian management)
s1: large rivers, woody debris doesn’t play as essential as a role
s2-3: medium rivers with fish
s4: small streams with fish
what are some of the best management practices for the different types of streams
S1: A reserve zone is not required.
• Retention rates should range from 70% retention to full.
• Favor maintenance of species, age, and size distributions.
• Retain wildlife trees.
S2-3: Have a reserve zone where timber practices are constrained
• Retain wildlife trees in management zone
• Manage windthrow hazard
S4: Reserve zone not required, but the follow practices should be considered.
• “Retain nonmerchantable confer trees, [and other plants] within 5 m of the channel to the fullest extent possible”.
• “Fall and yard away”
• “Remove dominant conifers and retain 50% of remaining
stems within 10m of channel”.
• “Retain all windfirm trees with roots embedded in the bank”
what is an estuary
where river meets sea
what are estuaries governed by
rivers
oceans
internal dynamics
what are the different types of estuaries
fjord
bar - built
river deltas
what are ocean’s inputs in estuaries
saltwater (upwelling nutrients)
tidal dynamics
marine detritus
animals
what are the river’s inputs in estuaries
freshwater
sediments
dissolved particulate carbon
nutrients (oceans have more nutrients, but rivers have different nutrients)
what is a salt wedge
when salt water and fresh water mix, salt water is heavier and it sinks
what is a river plume
A river plume is a freshened water mass that is formed in the sea as a result of mixing of river discharge and saline seawater
river inputs also mix horizontally, what way does it turn
north due to corals effect
what influences the relative importance of oceans, river, and internal dynamics on estuaries
size of river physical setting (enclosed vs exposed)
what are some of the functions of estuaries
nursing habitat
stop over habitat
what are estuaries being squeezed by
sea level rising
coastal development
how is the population of seals, sea lions, and orcas doing
seals : increasing
sea lions : mostly increasing
orcas: mixed
southern residents are struggling
what is there increasing evidence for about hatchery pink salmon
they have negative effects on other salmon species
has number of chinhook fished by humans increased or decreased in last 40 years
decreased
has number of chinhook fished by marine mammals increased or decreased in last 40 years
increased 6 fold
who harvests more chinhook marine mammals or humans
marine mammals
what is the marine mammal protection act
enables recovery of marine mammals
prohibits take of marine mammals
what is the pacific salmon treaty
mandates some level of protection and international management of salmon
