Download Map A - VernalPools.Org

Mapping and Modeling
for Regional Planning
Carol W. Witham
Sacramento Valley Chapter
California Native Plant Society
contributors:
David Ackerly
John Dittes
Julie Evens
Josephine Guardino
Robert F. Holland
Todd Keeler-Wolf
David King
September 2006
Vegetation Mapping
What constitutes a good
vegetation map for use in
regional planning?
Why do you need a
vegetation map?
• Vegetation is considered to be the best single
surrogate for more detailed habitat and
ecosystem information.
• Geographic Information Systems (GIS) can be
used to analyze vegetation and other
environmental factors to help fill some of the
data gaps and uncertainties related to species
and habitat conservation.
Typical mapping exercises
don’t provide useful information
A hypothetical
land cover map,
often referred to
as a vegetation
map.
* Indicates rare plant
occurrences.
Typical mapping exercises
don’t provide useful information
How the typical
planner and
other
stakeholders
see vegetation.
Typical mapping exercises
don’t provide useful information
What the typical
planner and
other
stakeholders
really see ☺.
Why current mapping efforts
don’t work
• Planners write the contracts with the
consultants who perform the mapping - or
worse - have the mapping done in-house.
• Mapping is often based on keystone or
listed species, usually animals.
• Most mapping is done from aerial imagery
interpretation with no ground-truthing.
• No real data on ecosystem, processes,
habitat, species or vegetation structure.
Why current mapping efforts
don’t work
• GIS jockeys often don’t understand
vegetation and only want to map what they
can unambiguously distinguish from the
aerial, generally land cover types.
• Mapping is limited by the resolution of the
aerial imagery, the minimum mapping unit
and the skills of the mapper.
• Time and money are often the most
important considerations in planning
efforts.
Integrated Vegetation Classification
and Mapping - overview
Stratify survey
locations by
variation in
aerial imagery
signatures.
Collect field
data.
Classify
vegetation
based on field
data.
Integrated Vegetation Classification
and Mapping - overview
Extrapolate
vegetation
classification
from field data
and identify
similar units on
aerial imagery.
Ground-truth
and refine as
appropriate.
Integrated Vegetation Classification
and Mapping - overview
More detail in
the vegetation
map gives a
better sense of
why the rare
plants occur
where they do.
* Indicates rare plant
occurrences.
Integrated Vegetation Classification
and Mapping - process
• Nested random sampling of vegetation in
the planning region.
• Analysis and classification of vegetation –
setting the rules to play by.
• Extrapolation of field data to aerial imagery
analysis and vegetation mapping.
• Attribute each map unit with factors such
as canopy cover or disturbance.
• Ground-truth the map and refine.
Integrated Vegetation Classification
and Mapping - benefits
• Links field data classification with mapping
efforts.
• Standardizes methods and terms among
agencies and between planning efforts.
• Provides more useful information on
ecosystems, processes, habitats, species
and vegetation structure.
• Can be used predictively to model habitat
requirements of species.
Integrated Vegetation Classification
and Mapping - drawbacks
• Planners and many consultants are
uneducated as to the value of detailed
vegetation classification and mapping.
• Often automatically rejected as too
expensive and time consuming.*
• Most land within planning areas is not
accessible for field data collection.**
• Fine-scale vegetation patterns cannot be
mapped with existing aerial imagery.
Actual Example of
Land Cover vs Vegetation Map
Map A
Land Cover Map
Map B
Vegetation Map
9 units
29 units
from a small sample area of the San Diego mapping effort
Courtesy of Julie Evens
How do we get from
Map A to Map B?
• Planners and their consultants must be made
aware of the conservation and economic
benefits of accurate vegetation mapping.
– Good mapping allows predictive modeling.
– Good mapping facilitates tracking change over time.
– Good mapping upfront is less expensive than doing
the maps over and over again.
• Conservationists must continue to advocate for
the use of best available science in regional
planning.
GIS Modeling
What is it and
how is it useful for
regional planning?
GIS Modeling –
a very brief overview
• GIS software and other statistical analysis
programs are used to compare one data
set against another data set.
• Coarse-scale data sets are available for
many environmental conditions (i.e. soils).
• Fine-scale data sets are developed
through field survey work (i.e. CNDDB).
• Hypothesis can be developed and tested
using these data sets.
GIS Modeling –
benefits and drawbacks
• It can be used to partially fill gaps and
uncertainties that result from never having
enough data to make decisions with
absolute certainty.
• It can be used predictively and with
historic data to detect change.
• It is modeling - a probability assessment
and not exact science.
• It is only as good as your worst data layer
and worst assumption.
Juncus leiospermus var. aharti
GIS Modeling to Predict
Plant Biogeography
CNDDB Records
Soils/Geology
Climate Data
Elevation
Slope
Courtesy of Robert F. Holland
number
crunching
Quercus douglasii
Jepson range:
Elevation: < 1200 m.
Bioregional distribution:
Inner North Coast Ranges,
Cascade Range Foothills,
Sierra Nevada Foothills,
Tehachapi Mountain Area,
n San Joaquin Valley,
San Francisco Bay Area,
Inner South Coast Ranges,
Western Transverse Ranges
(n slope)
GIS Modeling to Predict
Global Warming Range Shifts
Courtesy of David Ackerly
Hulsea breviflora
Courtesy of Todd Keeler-Wolf
GIS Modeling to Predict
Plant Population Locations
Input Grids
Modeling Results
Elevation
Soil Wetness
Index
Slope
Number
of
Fires
Geology
0 to 3 Grids Overlapping
4 Grids Overlapping
Vegetation Types
Courtesy of Todd Keeler-Wolf
5 Grids Overlapping
6 Grids Overlapping
Species Found
Search Area
Trails
Streams
Vernal Pools a special case study
Courtesy of David King
Vernal Pools study challenges
• Vernal pool and grassland vegetation has
not yet been adequately classified.
• Variations in vernal pool and grassland
vegetation are too fine-scale to map.
• Most vernal pools are on private property
and inaccessible for vegetation sampling.
• The South Sacramento HCP will cover
~344,000 acres of vernal pool grasslands.
Vernal Pools –
ecological assumptions
• Ecology and species composition can be
correlated with pool size and hydrology.
• Hydrology and period of inundation can be
correlated with pool size.
• Species diversity can be correlated with
variability in pool size and hydrology.
• Ecological function can be correlated with pool
interconnectivity.
• Landscape scale variability can be correlated
with geology and soils.
GIS Modeling to Predict
Highest Conservation Value
Vernal Pool Area/Density Index
Heads-up digitizing of all vernal pools
within the study area.
Overlay a random grid of 160 acre
squares.
Calculate the acreage of vernal pools for
each grid square.
Tabulate the number of vernal pools for
each grid square.
Highest diversity is approximated by
the areas that contain high acreage and/or
high numbers of vernal pools.
Courtesy of John Dittes & Josephine Guardino
GIS Modeling to Predict
Highest Conservation Value
Vernal Pool Area/Density Index
Heads-up digitizing of all vernal pools
within the study area.
Overlay a random grid of 160 acre
squares.
Calculate the acreage of vernal pools for
each grid square.
Tabulate the number of vernal pools for
each grid square.
Highest diversity is approximated by
the areas that contain high acreage and/or
high numbers of vernal pools.
Courtesy of John Dittes & Josephine Guardino
Summary
What are the
mapping and modeling
take-home messages?
Take-home thoughts!
• Moving from Map A to Map B will require
concerted efforts to educate planners on
the benefits of good vegetation maps.
• Better vegetation maps are more cost
effective in the long run and provide
greater assurances for conservation.
• Modeling is a great tool, but depends on
the quality of the data used for analyses.
We can’t solve problems by
using the same kind of
thinking we used when we
created them.
- Albert Einstein