SCALE, CONSUMERS AND LOTIC ECOSYSTEMS RATES (SCALER)
Walter Dodds1, Janine Rüegg1, Christina Baker2, Ford Ballantyne3, William Bowden4, Kait Farrell3, Michael Flinn5, Keith Gido1, Tamara Harms2,
Ashley Helton6, Jay Jones2, Lauren Koenig7, John Kominoski8, William McDowell7, Samuel Parker4, Amy Rosemond3, Ken Sheehan7, Chao Song3,
Matt Trentman1, Matt Whiles9, and Wil Wollheim7
1Kansas
State University, 2Universtiy of Alaska, 3University of Georgia, 4University of Vermont, 5Murray State University, 6University of Conneticut,
7University of New Hampshire, 8Florida International University, 9Southern Illinois Universtiy
• Ecological systems are
increasingly complex with larger
spatial scale, but few studies
explicitly consider scale.
• Experiments and sampling are
being conducted in five biomes
across the North American
continent.
Continent
• Small-scale experiments can
underestimate the strength of overall
relationships between biodiversity
and ecosytem function.
• Experiments nested across spatial
scales and along environmental
gradients can address scaling to
large scales appropriate for
management and relevant for
evolution.
• Streams are tractable systems to
address such questions.
• Methods are consistent across
biomes.
• Stream networks in each biome
are represented using spatial
datasets and ecosystem models.
Resource
supply rate
(N & P
addition,
source of C)
Arctic
Cariboo
Konza
Coweeta
Network (10 km2)
•Synoptic sampling throughout
watershed to parameterize and
test models that quantify
processes at network scales.
Large B
Small A
Value of
ecosystem
goods
&services
•Reach-scale exclosures with
consumer removal (> 3-5 mm)
across a gradient of stream
sizes.
Small B
Synoptic sampling
Reach exclosure sampling
Reach (100 meters)
Overall: How can small scale
ecological experiments be applied to
understand structure and function of
regional ecological systems?
Upstream control
(Large consumers retained)
Micro-scale exclusion ( ) reach
(Large consumers retained) – see habitat below)
5mm mesh screen with electric
wire along bottom of stream
Specifically:
• How can we use dm to 100-m
scale process measurements and
consumer manipulation
experiments to predict ecosystem
characteristics of stream
networks?
Downstream treatment
(Large consumers
removed)
Riffle
Pool
•Reaches minimum of 30 m to
encompass the major habitat
types.
Habitat (0.1 m)
Goal: To help design experimetal
methods at scales feasible for most
researchers that allow extrapolation
to watersheds.
• Habitat exclosures are paired
with an open and closed side
using mesh to exclude species
larger than 5 mm.
•At least two habitat types are
sampled, 4 replicates
Treatment
Control
• Quantifying ecosystem processes
at river network scales will require
accounting for the distribution of
abiotic drivers (temperature, light,
flow) defined by heterogeneity that
is superimposed on gradients of
river size.
• Consumer effects will have
influences across biomes via
biogeographical patterns of
community composition (we do not
view this as a continental gradient).
•Each reach-site includes an
upstream control reach with
consumers retained, a middle
reach with the habitat
exclosures, and a downstream
treatment with consumers
removed.
• Consumer removal (>3- 5mm)
electro-shocking followed by
physical exclusion.
• How do patterns of scaling vary
across an array of North American
biomes, and why?
Hypotheses
Luquillo
Sampling
Mid A
Research questions
• Determinting synoptic sampling
sites appropriate to a) inform spatial
modeling used as network-scale and
b) test validity of model.
Headwaters
to quantify
input
Mid B
Ecosystem functions
(production, system
respiration, nutrient
retention & cycling)
• Grain size (i.e., distribution of
sites)
•Stream metabolism and nutrient
uptake are response variables
Large A
Community
structure
(numbers & types
of species)
Site Selection
• Coverage and confounding factors
• Knowledge of complex ecosystem
responses to global and regional
change is needed for ecological
forecasting and requires the
identification of ecosystem response
mechanisms and their drivers.
Flood and
drying
(driven by
climate,
land use)
Challenges
Study design
Background
Treatment
Control
Side view
Top view
•Each exclosure plot contains
contain sediment baskets as
homogenized units.
•Developed chamber for
metabolism and nutrient uptake
at habitat-scale
Distribution
of total
benthic area
Grid overlay
Sub- Hypotheses
Scaling from reach to
watershed-scale:
• Scaling ecosystem rates
will be facilitated with a
stoichiometric approach of
C, and N transformations
that accounts for advectioncoupling of linked reaches.
• Consumers significantly
impact ecosystem processes,
and scaling their effect to
networks will require
understanding longitudinal
patterns of their diversity
and abundance.
Stadardizing methods
•Metrics and measures exist for cmto reach-scales, but are not possible
for networks.
• Consumers only can be exluded up
to reach scale
• Floods, droughts, permits,
equipment
Data management
• Data inflow from field sites
• Meta-data
• Data verification and
transfomration
Scaling from habitat to
reach –scale:
• Experimental
measurements of ecosystem
function rates at habitatscales can be extrapolated
to reach-scales when
habitat distribution and
their connectivity is
accounted for.
• Direct responses of
ecosystem rates to consumer
removal at habitat-scales
can be extrapolated to
reach-scales, but indirect
effects require accounting
for advective transport and
downstream accumulation.
• Functional consumer
composition (predators vs.
primary consumers) and
relative biomass will
determine removal effects of
large consumer on
ecosystem rates through
cascading effects.
• Data access
STREON in contrast to
SCALER
• Stream Experimental and
Observational Network (STREON)
is a consumer and nutrient
availability experiment embedded
within NEON.
• STREON experiments are done at
10 sites across the continent, but are
not replicated within a watershed.
• STREON only reflects spatial
scale in the extremes of large scale
divers such as climate among their
sites.
• SCALER will investigate how
STREON results might apply to
watersheds as well as providing
early testing of methodology that
will work across diverse sites.