Transcript Climate.Stream.Network_Herbst.updated.for

A SENTINEL MONITORING NETWORK FOR DETECTING
THE HYDROLOGIC EFFECTS OF CLIMATE CHANGE ON
SIERRA NEVADA HEADWATER STREAM
ECOSYSTEMS AND BIOLOGICAL INDICATORS
David Herbst
Sierra Nevada Aquatic Research Laboratory
University of California
Mammoth Lakes
[email protected]
Staff:
Bruce Medhurst
Scott Roberts
Michael Bogan
Ian Bell
Project funded 2010-2011 by Management Indicator Species program
of the US Forest Service, Region 5
Joseph Furnish, contract administrator
Outline Overview:
• How does climate change influence mountain stream hydrology?
• Why is this important to bioassessment and conservation?
• Using models forecasting hydroclimatic risks vs habitat resistance features
to design a monitoring network for the Sierra Nevada
• Preliminary results, insights to stressors, and applications of data set
Motivations for study:
• Forest Service mandate: advance and share knowledge about water and
climate change, and how to protect and restore aquatic habitats
(Furniss et al. 2010. Water, Climate Change & Forests; USFS PNW-GTR-812)
• Provide a reference stream baseline of natural conditions to produce
biological health standards for Management Indicator Species program in
National Forests of the Sierra (across 7 National Forests)
• Evaluate the extent of reference decline or drift that might occur with
effects of climate change, and use for calibration of CA-SWAMP biocriteria
standards in the Sierra
• Integrate climate change in planning & assessment of forest management
practices using BMIs for USFS R5
• Assist “Vital Signs” and “Inventory & Monitoring” programs of National
Park Service (in 3 Sierra National Parks)
• Develop prioritized watershed types for resilience-building management
planning based on documented vulnerability observed at sentinel streams
Background
• Modeling has provided some important insights and
testable hypotheses on how climate change
may alter
the
Headwater
habitat
thermal and hydrologic regime of streams,compression:
but these are no
substitute for real data on how aquatic life
are responding
*Drying
from above
*Warming
• Stream flow and water temperature records
showfrom
thatbelow
area in
regime changes are already underway*Reduced
>urgent habitat
to establish
lower late summer flows
and maintain an ecological detection network
• Mountain ecosystems with pronounced elevation gradients
are especially vulnerable in shifting rain/snow transition
zones, with habitat compression occurring in headwaters,
and altered flow timing and warming occurring everywhere,
all creating ecological challenges
• Design of a monitoring network for detecting climate
change effects on mountain streams requires use of
models and landscape features to predict where and how
hydroclimatic conditions will shift
Regulatory Application of Study:
Biological water quality assessment programs
• Programs depend on reference streams to serve as
standards for assessing impaired biological integrity
• But what if reference stream conditions are not stable
and change beyond natural levels of variation in location
and time? Assessment becomes a moving target.
High quality reference sites have most to lose:
• If reference values degrade and become more variable,
this decreases the signal-to-noise ratio leading to loss in
capability of reference condition to detect impairment
• Climate change may result in reference drift
>degraded condition lowers the biological standard
• Need for re-calibration of bio-objectives / standards
A Changing Hydrograph:
Shift in the mountain snowmelt flow regime
DEC
NOV
OCT
SEP
AUG
JUL
JUN
MAY
APR
MAR
FEB
JAN
Stream Discharge
Biological responses of native benthic invertebrates to
Developing and anticipated
warming and altered flow regime:
changes with climate•Life
warming
history/phenology: >favors shorter generations,
temp
& loss of long-lived taxa
rain-on-snow floods
>more generalist, fewer specialist traits
wetter & more erratic
>shift to common, widespread taxa
winter flows >movement into headwater refugia?
•Migration:
•Abundance: >warming increases growth for some
earlier snowmelt
but others cannot survive warming
>habitat areas
diminished under low
earlier & prolonged
summer flows
(lost from
low summer
flows food chain)
•Physiological stress:
>loss of sensitive species
•Emigration escape:
>drift in
currents
or flight
periodic
drying
of
perennial (resistant
streams stages)
•Dormancy:
>hunker-down
•Shift from a perennial stream community to an
intermittent type (fewer, seasonal-adapted taxa)
•Local extirpation of species
D
E
S
I
G
N
3rd-order size watersheds
of Sierra Nevada
Natural Resistance Filters: rank low to high
Reference selection filter using GIS:
mininimum roadedness or land use,
no reservoirs, all above 1000 m)
Reference
3rd-order watersheds
•Northness Aspect (snowmelt timing, temp, vegetation)
•Groundwater contributions (geology/springs)
•Riparian cover and meadow area (water storage)
field reconnaissance
of best candidate sites
(local impacts minimal to none)
Climate forecast filter:
VIC-hydrological model
prediction of snowpack
and stream flow
Ranked list of watersheds
by quartiles of lowest
and highest climate risk
Low Risk
High Resistance
High Risk
High Resistance
Low Risk
Low Resistance
High Risk
Low Resistance
3 watersheds each category
with differing exposures
and expectations for the
influence of climate change
►Designed as a natural experiment
testing hypotheses of risk & resistance
Historic Hydrograph (1950-2000)
14
12
surface flow
SWE
10
8
baseflow
6
4
2
0
0
30
60
90
120
150
180
210
240
270
300
330
360
Day of Year
VIC model
Output:
Use
Forecast
Change as
Risk Level
Runoff (mm/day)
Baseflow (mm/day)
Snow Water Equivalent (mm/100)
Modeled Future Hydrograph (2041-2060)
14
Winter flows more variable
With extreme flow events
12
Surface flow lower
& depleted earlier
10
Ground snow cover less
& disappears sooner
8
6
Baseflow lower
4
2
0
0
30
60
90
120
150
180
210
240
270
300
330
360
Day of Year
Runoff (mm/day)
Baseflow (mm/day)
Snow Water Equivalent (mm/100)
12 catchments
24 sites total
(tributary site
nested in each
catchment)
Sentinel Monitoring Network
for Sierra Nevada
Selections based on summed
Climate-Risk factors from VIC:
•Reduction in April 1 SWE
•Change in total AMJ run-off
•Change in total AMJ base-flow
upper quartile of change =high risk
lower quartile of change =low risk
Natural Resistance:
upper / lower quartiles for
North-facing = low vulnerability
South-facing = high vulnerability
Plus, resistance conferred by deep
groundwater-recharge potential
from basalt / andesite geology area
(Tague and others 2008)
17 in 7 National Forests
7 sites in 3 National Parks
Nested Tributaries
12 catchments + tributary in each:
24 stream reaches total network
Tributary
Reach
1° or 2°
Catchment
Reach 3°
20-100 km2
Monitoring
Protocols:
SWAMP-based
Survey Monitoring data collected:
•150-m reach length
•channel geomorphology
including bankfull cross-sections
(substrata-depth-current profiles,
embeddedness, slopes, bank and
riparian cover, riffle-pool ratio, etc)
•conductivity, alkalinity, SiO2, pH
•large woody debris inventory
•cobble periphyton (Chl a, taxa IDs)
•CPOM & FPOM resources
•macroinvertebrates (RWB & TRC)
•adult aquatic insect sweeps
•photo-points
Upper Bubbs
Instrumentation set up at
monitoring stations:
Stage-level pressure transducers
and Temperature probes at
catchment reaches (water and air)
90 min recording intervals
Temperature probes
at tributary reaches and
Stage-level probes
GIS Analysis at each:
Land use, Roads, Geology,
Riparian, Meadow & Forest cover,
Groundwater recharge
Tyndall
Analysis of logger data:
Hydrographs and flow metrics
Flow-separation curves (baseflow)
Thermal profiles
Elevation and Region
Elevation (m)
4000
Streams in the southern region are at
mid-to-high elevations, with low levels
of conductivity and dissolved silicate
(snow-melt dominated)
3000
2000
1000
0
36
37
38
39
40
GPS Latitude
41
42
Chemistry and Region
Conductivity (uS)
250
Streams in the northern region are at
lower elevations, with higher levels
of conductivity and silicate
(groundwater mineral content)
200
150
Northern streams support higher levels
of biological diversity than in the south
100
50
Taxa Richness and Region
0
36
37
38
39
40
GPS Latitude
41
42
60
Taxa Richness
Chemistry and Region
40
30
SiO2
70
20
50
40
w/o
M&Ms
30
10
20
36
0
36
37
38
39
40
GPS Latitude
41
42
37
38
39
40
GPS Latitude
41
42
~350 taxa
identified
to date
Incl.M&Ms
Community Similarity
Groupings
Climate Change
Distance (Objective Function)
3.9E-03
8.1E-02
1.6E-01
2.3E-01
3.1E-01
Information Remaining (%)
100
North of
Yosemite
Yosemite
and South
75
50
25
0
Butte
Willow
McCloud
EF Moosehead
EF Nelson
Cat
Robinson
Grassy Swale
MFCosumnes
Sagehen1
Sagehen2
Nelson
Warner
Cathedral
Upper Cathedral
Deer
Pitman
Snow Corral
Crown
Tyndall
Upper Bubbs
Forester
Upper Tyndall
SF Tamarack
Intermittent channel = shortest upstream length, low SiO2 snowmelt
Closer look at Intermittent flow: stress of periodic summer drying
>perennial upstream length used as indicator of dependable flow
70
70
Richness
Taxa Richness
60
60
50
50
40
40
30
30
20
20
Silicate < 15 mg/L
10
10
Silicate > 15 mg/L
00
0.1
0.1
10
100
11
10
100
Channel Length
Length (km)
(km)
Upstream Channel
risk drying)
drying)
(lower values risk
1000
1000
Short headwater streams most susceptible, having least taxa richness.
But what protects some headwaters and not others?
>Groundwater inflows (higher SiO2) sustain baseflow and resist drying
>low SiO2 snowmelt-dominated streams risk drying but support more
richness as channel length increases (=perennial flow)
Biodiversity present in treatment groups have similar initial richness levels
for 2010, a near-average water year > So there is diverse scope for response
EPT Richness and Treatment Category
50
+ 1 SD
Trait Character States:
•79% of these taxa are cold-adapted*
•89% are either semi- or uni-voltine
(have ≥1 yr life cycles)
•67% prefer riffle habitat (high flows)
EPT Richness
40
30
20
10
*except intermittent stream just 50%
0
Risk = High
Vulnerability = High
High
Low
Low
High
Low
Low
Statistical equivalence of treatment groups:
=Baseline for
Group with most risk and vulnerability also
further comparisons
has the most scope for response.
All groups exceed the Sierra reference level
for maximum EPT = 23 taxa [blue line eastern Sierra IBI]
Flow Regime Types Observed*
(habitat ecological templates, after Poff and others)
Are there associated BMI community types?
2.02.0
2.0
McCloud
Deer Creek
River 2010-2011
Cathedral Creek 2010-2011
2.0
Upper Bubbs Creek 2010-2011
Depth (m)
Depth
Depth
(m)
(m)
Depth (m)
1.51.5
1.5 1.5
1.01.0
1.0 1.0
0.50.5
0.5
0.5
0.0
0.00.0
0.0
AugSep
Sep Oct
Oct Nov
Nov
Dec
Jan
Feb
Jun
JulJul
AugAug
Aug
Aug
Sep
Oct
Nov Dec
Dec Jan
Jan Feb
FebMar
Mar
MarApr
Apr
AprMay
May
May
Jun
Jun
Jul
Aug
Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug
2020
Cathedral
McCloud
Deer
Creek
River
Creek
2010-2011
2010-2011
2010-2011
Upper
Bubbs
Creek
2010-2011
Temperature (C)
1515
Temperature (C)
• 1. Stable winter flows and
temperatures during ice cover
(though R on S may occur),
rapid spring snow-melt and
summer recession, prolonged
cool temps (<10ºC)
• 2. Winter rain and snow,
instable ice-snow cover,
rising flows through winter
and spring, warm summer
temperatures (≥15ºC)
• 3. Stable groundwaters sustain
high flows and cooler more
constant temperatures (≤10ºC)
• 4. Spatial intermittent flows,
losing reaches, warm, variable
1010
5
5
0
0
-5
-5
Aug
Aug
*1. Snow
2. Rain+Snow
Sep
Sep
Oct
Nov
Dec
Oct
Nov
Dec
3. Groundwater
Jan
Jan
Feb
Feb
Mar
Mar
Apr
May
Apr
Jun
May
Jul
Jun
Aug
Jul
Aug
4. Intermittent-Flashy
2011: high and prolonged spring runoff
and water chemistry change: lower pH (-0.75 mean)
Wilcoxon signed-rank paired comparison 2010 to 2011
p<0.0001 (22 of 24 streams), decreasing from an average of 7.22 to 6.47
pH decrease with high runoff dilution of inflows,
most severe at streams with lower pH and less acid neutralizing capacity
Biological Consequences?
Of late runoff (3-4 wks), higher flows (50-75% increase), and reduced pH?
8.5
8.5
2010 data
2010 data
8.0
7.5
7.5
pH
pH
8.0
7.0
7.0
6.5
6.5
6.0
6.0
0
10
20
30
EPT Diversity
40
50
100
1,000
10,000
100,000
Density (ind/m2)
2011 prelim data shows no loss of diversity/abundance: resilient so far
What’s next: using the data obtained and
maintaining the network into the future
• Sustain funding - possibly through interagency cost-sharing?
• Contribute results to California Climate Change Portal,
and integrate into assessment reports of US-GCRP
• Apply flow and temperature recordings for the past year to
validate and calibrate ungaged flow models, and use to backcast past flow histories (use by USGS, DWR?)
• Further analysis of 2011 data to evaluate reference stability
and biological indicator responses to record snowfall, high
runoff, reduced pH, and delayed spring onset
• Further analysis of 2012 low-flow year as substitution for
future hydroclimatic conditions and 2013 as repeat?
• Do communities correspond to hydrographic regimes?
Invite Collaboration
• High elevation hydro- and thermo-graphs for model
development >>rare data from headwater streams to share
• Stable isotope analysis of heavy water (18O & 2H) at each site
to determine groundwater contribution (mixing models)
Conservation Applications
• Although there are many endemic and montane-adapted
native species of aquatic inverts in the Sierra Nevada,
biogeography and habitat requirements are poorly known, so
surveys supply a basic biodiversity inventory
• Improved understanding of natural flow and temperature
regimes, and microclimate of headwater streams
• Identify habitats & taxa changing most, and how these might
be protected from climatic effects on hydrologic and thermal
regimes > refugia & aquatic diversity management areas
• Extend GIS analysis of environmental resistance factors to
assess habitat sensitivity to climate risk
• Use ecological trait analysis to assess biotic vulnerability
• Develop management framework to prioritize stream types
for building resilience and protection of most vulnerable
watersheds (riparian & meadow restoration, protect
groundwater infiltration paths, reduce soil loss/debris flows
by managing grazing, logging & road disturbance)
• USFS-NPS adaptive planning in climate change stewardship
conclusions
• Network is up and running and the biological indicators
provide a strong foundation for detecting change
(biodiversity & trait sensitivities to hydro-climate change)
• North–South stream groups show distinct differences in
snowmelt vs groundwater influence on hydrology (and
related water chemistry) and in biological communities
• Biological richness of northern streams is ecological
“insurance”, but this also means more to lose in a region
with the most severe climate risk predicted
• Though having less biodiversity, southern streams
harbor some vulnerable taxa with restricted distributions
• Intermittent drying poses a clear risk to sustaining
biodiversity, esp. in snowmelt-dominated streams, but
groundwater systems appear to be more buffered
(confirming a predicted climate risk-resistance)
• Lower pH and high & delayed flows of 2011 do not
appear to alter invertebrate communities under this
change, but what about 2012-13 drought years?