Transcript Slide 1

Range of Natural Variability
Pete Fulé
Northern Arizona University
• What is RNV?
• RNV relates to … Ecosystem
Management … Ecological Restoration …
Conservation Biology
• Historical forest structure and function
in the Southwest
What is RNV?
• “A science of land health needs, first of
all, a base datum of normality, a picture
of how healthy land maintains itself as
an organism.”
Aldo Leopold (1941)
• What is the “base datum”?
• Terms: range of natural variability,
historical variability, reference
conditions
“We define natural variability as the ecological
conditions, and the spatial and temporal
variation in these conditions, that are
relatively unaffected by people, within a
period of time and geographical area …”
(Landres et al. (1999): Ecol. App. 9:1279-1288)
• “The (dynamic) conditions that would exist if
the dominant Euro-American culture had
never arrived, but Native Americans had
continued to use the landscape.”
(Stephenson (1999): Ecol. App. 9:1253-1265)
Why care?
• Modern human impacts may diminish species
viability.
• Coarse-filter management strategy conserves
even poorly understood species.
• Fewer external subsidies when manage within
bounds of system.
• Useful reference point for human-caused
impacts.
• Analysis at long time frames & large scales.
• Recognizes importance of disturbance.
• Spatial heterogeneity important for resilience.
Landres et al. 1999
RNV and Ecosystem Management
• Conservation of ecosystem structure,
composition, and function across the full
range of spatial and temporal scales:
–
–
–
–
Think long term
Save all the pieces
Save all the processes
Assure sustainability
Kaufmann et al. (1994)
Gen. Tech. Rep. RM-246
Ecosystem Needs Assessment
Ecosystem Needs
& Capabilities
Analysis
Area
Ecological
Principles
Applied at
Appropriate
Spatial
And Temporal
Themes
Fine Filter
Analysis
Coarse Filter
Analysis
Reference
Conditions
Existing
Conditions
Kaufmann et al. 1994, Gen. Tech. Rep. RM-246
Ecoregion   Subregion  
Landscape   Watershed/Land Unit
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•
•
•
•
•
Air Quality
Water Quality
Weather
Hydrology
Aquatic Systems
Geomorphic
Processes
• Fire/Fuels Regime
•
•
•
•
•
•
•
Corridors
Travel Linkages
Species Viability
Fragmentation
Habitat Relationships
Insects & Pathogens
Nutrient/Soil
Productivity
• Succession &
Community
RNV and Ecosystem Management
• EM (and other management approaches) are not
“science-based” but “science-informed.”
• RNV is fundamental to EM but is not necessarily the
goal.
• In Ecological Restoration, the RNV can become the
goal or target of a management action.
• But ER is a subset of EM (“tool in the toolbox”…).
• Ultimately our objective is not to pick some perfect
management paradigm, but to continually improve
and adapt management in an evolving relationship
between ecological and social constraints and
capabilities.
RNV and Ecological Restoration
• Ecological restoration is the process of
assisting the recovery and management of
ecological integrity. Ecological integrity
includes a critical range of variability in
biodiversity, ecological processes and
structures, regional and historical context,
and sustainable cultural practices” (Society
for Ecological Restoration 1998).
• “Ecological restoration is the process of
assisting the recovery of an ecosystem that
has been degraded, damaged, or destroyed”
(SER 2002).
Restoration shares many values with sustainable
resource management, conservation biology, and
land reclamation. Two distinguishing
characteristics are:
(1) The use of intact, indigenous ecosystems as the
point of reference;
(2) A focus usually at the scale of entire ecosystems.
Southwestern forest restoration traces its lineage to
Aldo Leopold. Key studies were done by Harold
Weaver (1940’s-50’s) and Charles Cooper (1950’s60’s), as well as many other scientists and resource
managers.
Reference Conditions: Leopold’s “base datum”
1. Reconstruct past conditions through dendroecological,
paleoecological, or other historical ecology techniques.
2. Measure relatively undisturbed contemporary sites to
compare to reconstructed data and to explore the effects of
altered modern conditions such as high CO2 levels.
3. Draw inferences from
ecological relationships
observed in disturbed
sites.
4. Restore ecological
conditions as a modern
model for observing
ecosystem function.
Information on RNV: Multiple
Lines of Evidence
• Information on RNV is often
fragmentary, limited, incomplete.
• Make use of multiple lines of evidence.
• Always recognize limitations of the
data.
Swetnam et al. 1999, Ecol. App. 9:1189-1206
Historical Ecology Methods:
Written & Oral Histories
• Written documents include historic
forest inventories, scientific/military
expeditions, colonial records, land
surveys, diaries, missionaries.
• Photographs and maps.
• Oral histories may be available or you
may develop an oral history to capture
local knowledge.
Written Histories & Photographs
• Goals and cultural filter
of the historian.
• Propaganda and
advertisement.
• Biases in scientific
studies.
• Biases in forest
inventories.
• Practical biases
(selection of trees in
land survey).
• All these factors also
apply to maps and
photographs.
Photo G. Pearson 1909, Grandview (Grand Can.)
Courtesy Rocky Mountain Research Station
Mt. Trumbull, Arizona: 1870
Moore et al. (1999), Ecol. App. 9:1266-1277.
Mt. Trumbull, Arizona: 1995
Moore et al. (1999), Ecol. App. 9:1266-1277.
Andrew Sanchez Meador
Logging near Cloudcroft from 1903, courtesy of the Rick Miller collection of
historic photos. There are historic Mixed Conifer plots in "Cox Canyon" (south
of Cloudcroft) and Douglas-Fir plots near (what is now) Pine Campground.
Detail of a forest plot mapped in 1915 by G. Pearson
and T. Woolsey, Fort Valley Experimental Forest, AZ
Check mark on Woolsey map represents a ponderosa pine seedling over 12“;
X with a line under it is a cut yellow pine stump.
Andrew J. Meador
Andrew Sanchez Meador
Taos: several Woolsey plots around Taos, but most have not been found. Amole,
Gallegos, Cienaga, Osha Canyon, Rio Pueblo, La Junta, and numerous plots in
Angostura. This is a pine plot at Amole.
Andrew Sanchez Meador
Cienaga post-fire ingrowth.
Written and Oral Histories
Include Traditional Knowledge
• Native American sources
– Kat Anderson, California tribes
– Thom Alcoze, Kaibab Paiute & Cherokee
• Anthropological sources
– Ranching, farming, logging practices
• Relationship between historical sources and
archeological evidence
• Relationship between historical sources and
ecological evidence
– Population and fire in Mexico
– Apache presence/cambial scars/fire in New Mexico
Historical Ecology Methods:
Dendroecology
• Application of dendrochronology
(crossdating tree rings) to ecological
questions.
• Dendrochronology invented in Flagstaff!
• Basics of dendrochronology
• Climate example
• Forest structure example
Laboratory of Tree-Ring Research, University of Arizona
Woodhouse & Bauer: World Data Center A
Woodhouse & Bauer: World Data Center A
Reconstructing Forest Structure
with Dendrochronology:
Gus Pearson Natural Area
• Dendrochronology for tree age
• 100% sampling of dead trees
– Test of reconstruction methods
– Test of accuracy of restoration silviculture
• Mapping of all tree positions
• Age structure: RNV & target for
restoration
• Age structure of groups: regeneration
and fire patterns
Assessing Age Structure for Ecological Restoration
# Trees
20
10
15
45
16
15
16
85
17
55
18
25
18
95
0
GPNA 1992
Mast et al (1999)
Ecol. App. 9:228-239
6000
4000
2000
85
19
45
19
05
19
65
18
25
18
85
17
45
17
05
17
65
16
25
16
85
15
15
45
0
1992 Age Frequency
1994 Age Frequency
1876 Age Frequency
1.2
0.8
0.6
0.4
0.2
Tree Age
Mast et al. 1999, Ecol. App. 9:228-239
540
510
480
450
420
390
360
330
300
270
240
210
180
150
120
90
60
30
0
0
Frequency
1
Restoring Spatial Structure of the Forest
Changes in forest structure since 1876 at the
Gus Pearson Natural Area ecological restoration site
1876
1992
Covington et al. (1997)
Journal of Forestry 95:23-29
After Full Restoration
Restoration Techniques
• Overstory trees: thinning, species composition,
spatial pattern, old-growth.
• Understory herbs and shrubs: natural
regeneration, seeding, planting.
• Fuels:
accumulated fuels, canopy fuels, dead biomass
as nutrient sources and habitat.
• Fire: re-introducing fire, unique initial burn
conditions, smoke.
• Monitoring and adapting:
making changes.
evaluating results and
Covington, W.W., P.Z. Fulé, M.M. Moore, S.C. Hart, T.E. Kolb, J.N. Mast, S.S. Sackett, and M.R. Wagner. 1997.
Restoration of ecosystem health in southwestern ponderosa pine forests. Journal of Forestry 95(4):23-29.