Historical Changes to Culturally-Important 

Riparian Plants along the Colorado River:

a progress report on a pilot study integrating science 

and traditional ecological knowledge

Helen Fairley, Sociocultural Program Manager, GCMRC

2017 Annual Reporting Meeting 

Phoenix, Arizona 

January 24, 2017
Outline

 Introduction

 Overview of project need and objectives

 GCDAMP goals and Desired Future Conditions

 Drivers of vegetation change

 Project summary

 Literature compilation

 Photo matching

 Analysis

 Next steps and future applications
Why this study?

 Plants have cultural value –- as habitat (for insects, 

animals, humans), as food, traditional medicine, source 

of biodiversity, etc. (Values are culturally-determined!)

 Dam operations change riparian plant communities by 

altering the hydrology, nutrient supply, sediment 

supply, and disturbance regime of the natural system

 Many existing studies discuss effects of dams on 

vegetation but few examine effects to culturallyimportant plants (or to TCPs and cultural landscapes)
Why this study? (continued):

 Cultural values influence why we care about plants 

and also why and how we study plants

 GCMRC vegetation monitoring data driven primarily 

by biology science questions, not cultural concerns

 Tribal ethnobotanical inventories and veg monitoring 

data not well integrated with other GCDAMP studies

 Need for baseline information to inform future 

vegetation management and restoration activities 
AMP Goals, INs and SSQs

 AMP Goal 6: Protect or improve the biotic riparian and spring 

communities, including T&E species and their habitats

 CMINs 6.1.1, 6.2.1., 6.5.1, 6.6.1: Determine and track the 

abundance, composition, distribution and area of terrestrial 

native and non-native vegetation species in the CRE. 

_________________________________________________________ 

 SSQ 2-1: Do dam-controlled flows affect (increase or decrease 

rates of erosion and vegetation growth at archaeological sites 

and TCP sites, and if so, how?

 SSQ 2-2: How do flows impact old high water zone terraces in 

the CRE . . . ?

 SSQ 2-7: Are dam-controlled flows affecting TCPs and other 

tribally-valued resources in the CRE, and if so, in what respects 

are they being affected, and are those effects considered 

positive or negative by the tribes who value these resources?
8+ Desired Future Conditions 

 GCDAMP stakeholders have expressed desire for:

 Native riparian systems that are diverse, healthy, productive, 

self sustaining, and ecologically appropriate 

 Native, self-sustaining riverine wetlands

 Riparian vegetation and habitat with appropriate mix of ages

 Habitat for sensitive species

 Habitat for neotropical migratory birds, waterfowl, native birds 

 Healthy, self-sustaining populations of native riparian fauna 

(both resident and migratory) 

 A river corridor landscape that matches natural conditions as 

closely as possible

 Attributes of Traditional Cultural Properties and their 

culturally appropriate conditions are maintained 
Drivers of vegetation change 

 Regional climate change 

(e.g., drought, killing frosts)

 Specific weather events 

(e.g., debris flows)

 Diseases, pathogens 

 Non-native invasions

 Direct human impacts (e.g., 

trampling, selective removal)

 Human alteration of natural 

disturbance regime (e.g., fire, 

grazing, dam operations)
Drivers of Riparian Vegetation Change

 Hydrology Dominates!

 Volume of flow

 Variability of flows

 Seasonality of high flows

 Seasonality of low flows

 Floods (presence/absence/size/duration)

 Location and type of sediment deposited by flows

 Nutrients in water & fluvial deposits

 Other interacting factors (invasive species, 

pests, human activities, etc.) secondary 
Original Project Goals: 

Link TEK (ethnobotany) with western science to 

answer the following questions:

 Question 1: How have attributes* 

of culturally-valued riparian plants 

changed since closure of Glen 

Canyon Dam?

• Abundance, distribution, density, diversity, size

 Question 2: Have changes in the 

abundance and distribution of 

culturally-valued plants affected 

TCPs / cultural values important 

to GCDAMP Tribes? If so, how?

Photograph by E. Palmquist

Photograph by M. Yeatts
Pilot Study Focal Species

 Goodding willow (Salix gooddingii)

 Cottonwood (Populus fremonti)

 Netleaf Hackberry (Celtis reticulata)

 Honey Mesquite (Prosopis glandulosa)

 Coyote willow (Salix exigua)

 Seep willow (Baccharis emoryi, B.salicifolia)

 Apache plume (Fallugia paradoxa)

 Arrow weed (Pluchea sericea)

 Common reed (Phragmites australis)

 Cattail (Typha sp.)

 Horsetail (Equisetum sp.)

 Dropseed (Sporobolus sp.)

 Indian Rice Grass (Achnatherum hymenoids) 

 Also Prince’s plume (Stanleya pinnata), Globemallow (Sphaeralcea ambigua), 

and Canyon Grape (Vitis arizonica)

Trees

Shrubs

Grasses &

Grass-like

Plants
Methods

 Part 1: Compile data from multiple sources:

 Match and analyze historical photos

 Compile and analyze published literature

 Compile unpublished monitoring data

 Part 2: Engage tribal members to elicit 

perspectives about significance of changes

 Structured interviews

 Unstructured interviews

 Choice experiments
Sources of Information 

 Published articles and reports (botanical, 

archaeological, etc.)

 Vegetation monitoring data

 Historical photography and recent photo matches 

(Stanton-1889/90, Birdseye-1923, Webb- 1990s-2010s)

 Historical journals (Clover, Nevills, etc.) 

 Oral traditions
Published literature

 Scientific literature is extensive, varies by species. 

For example:

 hundreds of articles / books about Cottonwoods

 rapidly increasing literature about Phragmites sp. 

 virtually no literature about arrowweed life history

 Ethnobotanical literature extensive but uneven

 Final bibliography focused on information important 

for restoration of native riparian species
 Cottonwood (Populus fremonti) and Goodding Willow seed 

dispersal needs to be coincident with spring floods for 

successful propagation

 Propagation benefits from gradual flood recession

(< 6 cm/day for Populus; <4cm/day for Salix)

 Susceptibility to flood impacts differ: Salix and Populus

seedlings more resilient to scour and burial than Tamarix

 Tamarix, Populus, Salix seed dispersal timing overlaps, but 

is not identical – timing of flows matter!

Shafroth, P.S. and 8 others, 2010, Ecosystem effects of environmental flows: 

modelling and experimental in a dryland river. Fresh Water Biology 55, 68-85.

Example: Shafroth et al. 2010 

“Ecosystem Effects of Environmental Flows”
Photo Matching & Analysis Component 

 Photo

1889

1992

2011

Glen Canyon, RM -10.3

Photograph by F.A. Nims, Dec. 23, 1889 

Photograph by T. Melis, Feb. 10, 1992 

Photograph by B. Lemke, April 21, 2011 
Photo Matching

1. Relocate historical view

2. Relocate exact position 

of original photographer

3. Replicate the view

4. Compare identical views 

at different time periods

5. Record plant differences 

between the images

6. Document differences 

across multiple images

7. Summarize changes 

throughout river corridor

Top Image: RB Stanton, 1890

Bottom Image: RH Webb, 1990
Limitations of historical image matching

 quality of imagery

 ability to identify species 

 seasonal differences

 representativeness

 obtaining high-quality 

photo matches requires 

large time investment 

 methods for quantifying 

change difficult to apply 

(except for large distinctive 

species, e.g., barrel cactus)

Stanton Photo, 1890

RH Webb Photo, 2010
Photo Analysis

Scott M.L., Webb R.H., Johnson R.R., Turner R.M., 

Friedman J.M., and Fairley H.C. In review. Evaluating 

Riparian Vegetation Change in Canyon-bound Reaches of 

the Colorado River Using Spatially Extensive Matched 

Photo Sets. Chapter 10. In: Johnson R.R., Carothers 

S.W., Finch, D.M., Kingsley, K.J.,and Stanley, J.T. 

(editors) 20XX. Riparian Research and Management: 

Past, Present, Future. Gen. Tech. Rep. RMRS-GTRXXXX. Fort Collins, CO: U.S. Department of Agriculture, 

Forest Service, Rocky Mountain Research Station
Results of sample analysis, 1990-2012

 Woody vegetation (.e.g., tamarisk, baccharis) 

increased throughout river corridor, 1990-2012

 89% of analyzed photo matches showed 

increases in tamarisk 

 53% showed increases in Baccharis sp.

 2% showed clear increases in Salix exigua

 9% showed no significant change

 <2% showed a decrease

 Less change in narrow canyon-bound reaches

Preliminary data – do not cite
Analysis Results, continued

 Most vegetation increase is below 45K cfs

 Above 45K, some vegetation changes are due to 

encroachment of OHWZ and desert species (e.g., 

mesquite, acacia, cactus)

 Some die-back of OHWZ mesquite canopy 

 Some changes due to human intervention (e.g., 

Russian olive removal, experimental planting 

mesquite in NHWZ) – need systematic documentation!

Preliminary data – do not cite
Soap Creek, RM 11.5

Photograph by E.C. LaRue, August 02,1923

Photograph by A.H. Fairley, April 29, 2017
Rattlesnake Camp, RM 74.5

Photograph by E.C. LaRue, August 15,1923

Photograph by A.H Fairley, May 3, 2017
Fossil Canyon, RM 124.8

Photograph by E.C. LaRue, September 6,1923

Photograph by A.H Fairley, May 8, 2017
Randy’s Rock, RM 126.1

↓

Photograph by E.C. LaRue, September 6,1923

Photograph by A.H Fairley, May 10, 2017
National Canyon, RM 166.9 Photograph by E.C. LaRue, September 16,1923

Photograph by A.H Fairley, May 11, 2017
Stairway, RM 171.5

Photograph by E.C. LaRue, September 17,1923

Photograph by A.H Fairley, May 11, 2017
RM 194.9

Photograph by E.C. LaRue, September 25,1923

Photograph by A.H Fairley, May 11, 2017
RM 197.0

Photograph by E.C. LaRue, September 25,1923

Photograph by A.H Fairley, May 11, 2017
Parashant, RM198

Photograph by E.C. LaRue, September 25,1923

Photograph by A.H Fairley, May 12, 2017
Granite Park, RM 209.1

Photograph by E.C. LaRue, September 28,1923

Photograph by A.H Fairley, May 14, 2017
RM 222.3

Photograph by E.C. LaRue, October 1,1923

Photograph by A.H Fairley, May 14, 2017
Next steps & future applications

 Next steps (FY2017):

 Continue matching 1923 images 

 Continue archival research

 Complete analysis of matched photos

 Finish compiling bibliography

 Future applications of results:

 Photo matches provide visual baseline for future 

comparisons of vegetation change

 Bibliography will help guide and inform future 

restoration efforts
Elicit Stakeholder Perspectives re: 

riparian restoration objectives?

Possible methods:

 Choice experiments using 

photo comparisons 

 “Which of paired photos 

do you prefer and why?”

 Semi-structured interviews

 Structured “opinion surveys”

 Focus group discussions

 Other methods? Photograph by M. Yeatts
Questions?