Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland...
-
Upload
ambrose-goodwin -
Category
Documents
-
view
222 -
download
0
description
Transcript of Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland...
![Page 1: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/1.jpg)
Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park,
Oregon Cascades, USA
Harold S.J. Zald, Oregon State University MTNCLIM 2010 | 06.09.2010 HJA | Blue River | OR
![Page 2: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/2.jpg)
Why Study Tree Invasion in Mountain Ecotones?
• Globally, treeline positions related to thermal conditions• Treeline movement a highly variable response to climate across multiple climate regions, species, & land use histories
• Treeline movement and meadow encroachment may influence: ecosystem productivity, carbon balance, energy budget, hydrological processes, species distributions, and biodiversity
Harsch et al. (2009) Ecology Letters
![Page 3: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/3.jpg)
Gentle Elevation Gradient Treeline
Denali National Park, Alaska
Multiscale Drivers of Tree Invasion
• Tree invasion fundamentally driven by regeneration processes
• Not just climate!
• Biophysical controls: topography, soils, disturbance, seed sources, facilitation, competition, etc.
• Biophysical factors can control spatial patterns & sensitivity to climate
Edaphic “Triple Treeline”
Banff National Park, Canada
Multiple Gradient Subalpine Parkland
Mount Hood, Oregon
![Page 4: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/4.jpg)
Spatial Autocorrelation of Biophysical Controls
Modified from Brooke et al. 1970
• Traditionally, observations of treeline movement &meadow invasion along transects with limited environmental gradients
• Biophysical variablesspatially autocorrelated
• Difficult to untangledrivers
![Page 5: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/5.jpg)
0 50 100 m
Applying New Technologies to Old Questions
• Light Detection and Ranging (LiDAR)
• Landscape characterization of fine-scale vegetation structure & topography
• LiDAR can be used to sample across multiple biophysical gradients at scales compatible regeneration processes
![Page 6: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/6.jpg)
Research Questions
• How have climatic andbiophysical factors controlled recentrates & spatial patternsof tree invasion?
Background:
• PNW tree invasion driven bysnow depth and persistence, believed to determine growing season length(Franklin et al. 1971, Woodward et al. 1995, Rochefort & Peterson 1996)
![Page 7: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/7.jpg)
• Mount Jefferson Wilderness Willamette NF
• Elevation: 1755-1840 m
• ~130 ha
• Tree islands of mountain hemlock & Pacific silver fir
• Geomorphology: glacial &
neoglacial debris flows
• No known fires
• Unknown grazing history
Study Area: Jefferson Park, OR
Jefferson Park
HJA
![Page 8: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/8.jpg)
LiDAR Derived Biophysical Variables
Bio
Overstory canopy
Influences snow depth & persistence,seed sources
Physical
Topographic position, elevation, radiation
Influence snow depth & persistence
Landform (glacial v. debris flows)
Disturbance, but also influences other biophysical variables
![Page 9: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/9.jpg)
LiDAR Driven Sampling
Sample along biophysical gradients believed to influence snow depth
& persistence
Topography (5 Classes)
Distance to overstory canopy(5 classes)
Combine grids (5 x 5 = 25 classes)
100 x 100 m moving window(20 clusters)
Stratified random sample(25 points per cluster)
100 x 100 m cluster
![Page 10: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/10.jpg)
• Mapping of overstory canopy by species
(potential seed sources)
• Spatial autocorrelation between explanatory variables accounted for
• Landscape-level estimates of invasion possible
LiDAR Driven Sampling Continued
![Page 11: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/11.jpg)
• Points located with sub-meter GPS
• 2 m diameter plots 390 on glacial landform 109 on debris flows
• Snow depth survey July 29- Aug 1, 2008
• All trees < 8m tall tallied by species& height (1620 trees)
• 505 trees aged
Field Data
![Page 12: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/12.jpg)
Spatial Patterns
• Snow depth in relation tobiophysical controls
• Tree abundance in relation to biophysical controls
Temporal Patterns
• Tree invasion over time
• Tree invasion and climate
Interactions of Climate &Biophysical Controls
Flow of Results
![Page 13: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/13.jpg)
More snow with less radiation, lower elevation, distanceMore linear, reduced interactions, less variance described
Mean:0.2m
95% CI:0.1-0.3m
Deb
ris F
low
sG
laci
al L
andf
orm
s Mean:0.67m
95%CI:0.6-0.8m
More snow in depressions, lower elevations, distance from overstory Nonlinear interactions between explanatory variables
Results: Snow Depth & Biophysical Controls
![Page 14: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/14.jpg)
Results: Multi-Scale Controls of Snow
Landscape context is important
• Larger landforms influence both overall snow depth and micro site controls of snow
• Smoother surface on debris flows
• Greater windredistribution of snow on smoother debris flows
![Page 15: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/15.jpg)
Results: Tree Abundance & Biophysical Controls
• Mountain hemlock associated with microtopography and distance to overstory canopy
• Silver fir strongly associated with distance to potential seed sources, followed by microtopography
• Relationships between tree invasion and biophysical variables much stronger on glacial landforms
Glacial landforms Debris flow
![Page 16: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/16.jpg)
Results: Temporal Patterns of Tree Invasion
• Not just an increase in densities1950: 7.8% of meadow area with tree invasion 2008: 34.7% of meadow area with tree invasion
• Invasion dominated by Mountain hemlock, Pacific Silver Fir restricted to under existing trees
• Invasion rategreater ondebris flows(0.75% v. 0.57% Yr-1)
![Page 17: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/17.jpg)
• Annual snowfallmost important, not temperature
• On debris flows tree invasion not associated with
annual snowfall
• On debris flows, positive association with spring snowfall!
Results: Climate, Landforms, & Invasion
Glacial Landforms
Adj R2 = 0.2887p ≤ 0.01
Debris Flows
Adj R2 = -0.0356p = 0.5
![Page 18: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/18.jpg)
Only For Hemlock on GlacialLandforms
• Hemlock invasion largely in years with low snow on ridgetops & midslopes
• During high snow years, less invasion overall & constrained to ridgetops
Results: Climate, Microtopography, and Invasion
![Page 19: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/19.jpg)
• Snow and tree invasion associated with multi-scale landscape controls
• Species matter
• Landforms & topography alter both the spatial patterns of tree invasion & response to climate
• Tree invasion on debris flow landforms
• Scale & landscape context matter
• Multiscale and context dependent responses pose problems for modeling future responses to climate at regional and global scales
• Need for experimentation (future climate now)
Conclusions
![Page 20: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/20.jpg)
Acknowledgements
Funding provided by:
USDA Forest Service, Pacific Northwest Research StationUSDA Forest Service, Forest Inventory and Analysis ProgramThe Native Plant Society of OregonHoener Memorial Fellowship, OSUWaring Travel Grant, OSU
Thanks to field assistants:Dan IrvineAlex Gonsiewski
![Page 21: Multiscale Climatic, Topographic, and Biotic Controls of Tree Invasion in a Sub-Alpine Parkland Landscape, Jefferson Park, Oregon Cascades, USA Harold.](https://reader035.fdocuments.us/reader035/viewer/2022062401/5a4d1b417f8b9ab0599a0f24/html5/thumbnails/21.jpg)
Questions?