Developing Riparian Vegetation Flow Response Guilds 

in the Grand Canyon

By 

Daniel Sarr, Dave Merritt, Emily Palmquist Julian Scott, Pat Shafroth, and Barb Ralston

USFS National Stream 

and Aquatic Ecology Center
Talk Outline

• My Background (in three slides)

• Review of Workplan Objectives

• Identifying Riparian Vegetation Flow 

Response Guilds in Grand Canyon

• Moving forward
Prologue: 

Golden Trout Wilderness, Sierra Nevada

Golden Trout (Oncorhynchus 

mykiss aguabonita) 

• How riparian ecosystems recover from disturbance?

• How do we measure ecological restoration?
Riparian forest, Cascade Mountains, Oregon

Acid geothermal fen, Lassen Volcanic NP, CA

A Riparian and Wetland Journey

Skaghard Turlough, Burren National Park, Ireland

Narrowleaf cottonwood riparian forest (Populus 

angustifolia), San Luis Valley, Colorado
Klamath Network Vital Signs Monitoring

1. Non-native,

invasive species

2. Keystone and Sensitive Plant and Animals

(Whitebark pine, aspen, amphibians)

3. Vegetation Communities

4. Bird Communities

5. Intertidal Communities

6. Water Quality

7. Aquatic Communities

8. Landcover, use, pattern

9. Cave Communities

10. Cave Environment

11. Weather & Climate

Core Vital Signs 12. Air Quality

Unfunded Vital Signs
Grand Canyon Monitoring and Research Center 2013-14 Workplan

The work proposes:

1. To use ecological and life-history traits of riparian plant species found along the 

Colorado River downstream from Glen Canyon Dam to define flow response 

guilds (sensu Merritt and others, 2010.)....

(Today’s presentation: Sarr et al. 2015)

2. To use traits of response guilds to identify ecological states for riparian 

vegetation and those conditions (flow scenarios) that cause states to switch. 

This approach recognizes a multi-state pathway and multiple steady states as a 

way to describe riparian vegetation dynamics. 

 (Completed : Ralston et al. 2014) 

3. To use remotely sensed imagery to quantify landscape scale changes in 

vegetation type and amount and to conduct change detection analysis of 

vegetation since 2002.

(Joel Sankey’s 2014 presentation: Sankey et al. In 

Revision)

Riparian Monitoring Objectives/Elements
Monitoring Riparian Vegetation in Grand Canyon

Approach Developed in 2012-2013, some refinement in 2014, with 

monitoring protocol under development

Vegetation is monitored annually near the end of the growing season 

(August – Early October)

Mixed Sampling Panel Approach

Randomly selected Channel Margin, Debris Fan, Sandbar Sites 

(70-96 sites)

Permanent (always revisit) Sandbar Sites (42 sampling sites)

Sampled on separate river trips
Monitoring Riparian Vegetation in Grand Canyon

• Three or four transects/site

– Nine 1m x 1m quadrat samples/ transect 

• Apportioned with Stratified 

systematic design

– Active Channel (3)

– Active Floodplain (3)

– Inactive Floodplain (3)

• Data Collected

– Vegetation presence and cover, including 

overhanging vegetation

– Height above river

– Soil texture

• See Emily Palmquist Poster!
Monitoring Riparian Vegetation in Grand Canyon

• Strengths

– Feasible (and fun)!

– Yields abundant floristic data 

across an array of riparian 

habitats

– Is fairly easy to learn and a great 

venue for including volunteers, 

collaborators

– Provides a reliable framework for 

allied riparian research

– Integrated with remote 

sensing/landscape scale 

mapping

• Weaknesses

– Yearly sampling could damage 

vegetation

– Safety on, damage to steep river 

banks

– Sample approach is slanted 

towards smaller plants

– Structural and demographic 

information is limited
Guilds and Functional Group Classifications

Guild = A group of functionally 

similar organisms

Theoretical Basis-Functional Group 

Classifications

– Grime 1977 CSR -(Competitor, Stress 

Tolerator, Ruderal) scheme

• Riparian Vegetation Flow Response 

Guilds (Merritt et al. 2010)

• Potential Applications in Grand Canyon

– By linking flow probabilistically to guild 

presence, we have a mechanistic linkage to 

riparian vegetation response
Guilds and Functional Group Classifications

Three Applications

1. Riparian Tree Regeneration in Oregon

2. Changes in Vegetation along an Impounded River in Spain

3. Developing Riparian Vegetation Flow 

Response Guilds in Grand Canyon
Guilds and Functional Groups – An Application

Alnus group

Pseudotsuga group

Quercus group

Acer group

Tsuga group

Stress 

Tolerators

Competitors

Ruderals

Predicting Riparian 

Tree Regeneration in 

Oregon

• 23 Riparian Trees

• Looking for general 

patterns of 

regeneration across 

climatic, topographic 

and disturbance 

gradients

• Classified into 5 

functional groups 

based on Flood, 

Drought, Shade, Heat 

Tolerance, and Seed 

Size Sarr, D., D. Hibbs, J. Shatford, and R. Momsen. 2011. Riparian Tree 

Regeneration in Western Oregon: The Roles of Life History, Environmental 

Gradients, and Disturbance. Forest Ecology and Management. 261(7):1241-

1253.
Tree Regeneration Patterns

Species Distributions Followed 

life history expectations

• Ruderals were most common 

near streams

• Stress Tolerators were most 

common in driest climates

• Competitors were common in 

wet climates away from stream 

edge

• Species diversity was highest in 

the driest watersheds, because 

stress tolerators could coexist 

with stronger competitors

• Life history classification 

greatly assisted interpretation 

of regeneration

Geographic and Topographic Patterns of 

Tree Regeneration (frequency)

Dry Wet

Sarr, D., D. Hibbs, J. Shatford, and R. Momsen. 2011. Riparian Tree 

Regeneration in Western Oregon: The Roles of Life History, Environmental 

Gradients, and Disturbance. Forest Ecology and Management. 261(7):1241-

1253.
Guilds and Functional Groups – An Application

Effects of 

Impoundment on 

Riparian Vegetation in 

Tietar River Basin, 

Spain

• 14 Riparian Trees

• Classified into 9 guilds 

based on 20 traits AND 

field data (314 

vegetation “bands”)

• Evaluated changes in 

vegetation composition 

between 77 predam and 

230 postdam “bands”

Bejarano, M.D., M. Gonzalez del Tanago,D. Garcıa de Jalon, M. Marchamalo, A. 

Sordo-Ward, and J. Solana-Gutie. 2012. Responses of Riparian Guilds to Flow 

Alterations in a Mediterranean stream. Journal of Vegetation Science 23 

(2012)443–458 

Rio Tiétar and Sierra de Gredos
Guilds and Functional Groups – An Application

Effects of Impoundment on 

Riparian Vegetation

• Interesting terminology Drought 

Tolerance/Flow Association

• Xeric/Torrential guilds are 

exclusively postdam

• Vegetation encroachment on 

channel since impoundment

• Moisture, flooding, soil texture, 

canopy are primary gradients 

structuring vegetation

• Substrate effects are most 

pronounced below dam, 

diminishing downstream Bejarano, M.D., M. Gonzalez del Tanago,D. Garcıa de Jalon, M. 

Marchamalo, A. Sordo-Ward, and J. Solana-Gutie. 2012. Responses of 

Riparian Guilds to Flow Alterations in a Mediterranean stream. Journal of 

Vegetation Science 23 (2012)443–458 

Tamujo (Fleuggea tinctoria) Shrubland

Credit: Wickimedia commons
Developing Riparian Vegetation Flow Response 

Guilds for Grand Canyon

Building a Traits Database for Colorado River 

Riparian Vegetation

• Palmquist and Ralston reviewed literature and online 

data to develop a traits database for 114 species 

sampled in Grand Canyon from 2012-2013

• Traits emphasized physiological and morphological 

attributes.

Physiological Traits

– Anaerobic Tolerance

– Drought Tolerance

– Salinity Tolerance

– Shade Tolerance

Morphological Traits

– Height at Maturity

– Rooting Depth 

– Vegetative Reproduction

– Seed Size
Delineation of Riparian Vegetation-Flow 

Response Guilds

(Guild Classification)

• Unsupervised Guild Classification

– Gower Distance Metric

• Supervised Guild Classification

– Rank Transformed 

– Upweighted

• Anaerobic Tolerance

• Drought Tolerance

• Height at Maturity

– Used a Euclidean Distance measure

Hierchical cluster 

analysis (HCA)

Hierchical cluster 

analysis (HCA)

Preliminary results, do not cite (Sarr et al., in prep.)
Evaluating Candidate Guilds

• Unsupervised Guild Classification • Supervised Guild Classification

Candidate Guilds

(From HCA)

Candidate Guilds

(From HCA)

SIMPROF Permutation 

Test of Group 

Significance

Create “factor”

Principal Coordinates 

Analysis Ordination 

(Visualization)

Minimum Group Size 

Criterion

(3 or more species)

Preliminary results, do not cite (Sarr et al., in prep.)
Results: Guilds and Functional Group Classifications for 

Grand Canyon Riparian Systems

• Unsupervised Guild Classification

– Seven Candidate Guilds

• Supervised Guild Classification

– Ten guilds, but three had less than 

three species, so 

– Seven Candidate Guilds

Significant Data Reduction

Given 114 species, each guild averages about 17 species 

Preliminary results, do not cite (Sarr et al., in prep.)
Cluster Analysis Results (Dendrogram)

Unsupervised Classification

LEPLAT SCHARU TAMRAM PLUSER SCHAME PASSMI CYNDAC DISSPI APOCAN EQUARV EQUHYE MUHASP POAPRA JUNNEV MENARV JUNCON TYPLAT JUNARC JUNART JUNENS SALEXI ELEPAL ELEROS PHRAUS SCHACU SCHPUN AGRSTO JUNTOR BOECYL CAREMO VERAME PSESTR BACEMO SONASP TAROFF PLAMAJ SONOLE ANDGER STEPAU BRILON FUNCYN HORJUB ELYCAN PLALAN LARTRI CELRET CERORB ACAGRE EPHVIR PROGLA CHLSPI ALHMAU ATRCAN EPHNEV PLEJAM LYCPAL FALPAR BOTBAR PLERIG CUCFOE ACHHYM ELYELY BROTEC ENCFAR HESCOM SCHSCO ERACUR OENELA ERALEH GUTSAR OENPAL SPOCRY SPOGIG DIGCAL SPOCON SPOFLE BRORUB ARIARI EPHTOR MIRMUL ISOACR SPOAIR BACSAR BACSER BOUBAR PORGRA SALTRA BEBJUN DICCAN MELOFF BRODIA EROCIC LACSER LOTWRI PIPMIL ARTLUD MUHPOR EUTOCC POROLE SALGOO POLMON POLVIR CONCAN BACSAL AGREXA SYMSUB DATWRI BROCAT LOLPER ECHCRU XANSTR FRAVEL BROARV FESTHU

Samples

0

10

20

30

40

50

Dis

similarity

Resemblance: S15 Gower

Sim8Gower5

d

c

a

b

f

g

e

Unsupervised

Preliminary results, do not cite (Sarr et al., in prep.)
Cluster Analysis Results

Unsupervised Classification

-40 -20 0 20 40

PCO1 (54.2% of total variation)

-40

-20

0

20

40

P

C

O

2 (21.3

%

of total variatio

n)

Resemblance: S15 Gower

Sim8Gower5

d

c

a

b

f

g

e

ACAGRE

ACHHYM

AGREXA

AGRSTO

ALHMAU

ANDGER

APOCAN

ARIARI

ARTLUD

ATRCAN

BACEMO

BACSAR

BACSAL

BACSER

BEBJUN

BOUBAR

BOTBAR

BOECYL

BROARV

BROCAT

BRODIA

BRILON

BRORUB

BROTEC

CAREMO

CELRET

CERORB

CHLSPI

CONCAN

CUCFOE

CYNDAC

DIGCAL DICCANDATWRI

DISSPI

ECHCRU

ELYELY ELYCAN

ELEPAL

ELEROS

ENCFAR

EPHNEV

EPHTOR

EPHVIR

EQUHYE EQUARV

EROCIC

ERACUR

ERALEH

EUTOCC

FALPAR

FESTHU FRAVEL

FUNCYN

GUTSAR

HESCOM

HORJUB

ISOACR

JUNART JUNARC

JUNCON

JUNENS

JUNNEV

JUNTOR

LACSER

LARTRI

LEPLAT

LOLPER

LOTWRI

LYCPAL

MENARV

MELOFF

MIRMUL

MUHASP

MUHPOR

OENPAL OENELA

PASSMI

PHRAUS

PIPMIL

PLEJAM

PLALAN

PLAMAJ

PLERIG

PLUSER

PORGRA

POLMON

POROLE

POAPRA POLVIR

PROGLA

PSESTR

SALEXI

SALGOO

SALTRA

SCHACU

SCHAME

SCHARU

SCHPUN

SCHSCO

SONASP

SONOLE

SPOAIR

SPOCON

SPOCRY

SPOFLE

SPOGIG

STEPAU

SYMSUB

TAROFF

TAMRAM

TYPLAT

VERAME

XANSTR

NL_HT_mat

SMS_Veg

Anae_tol

Drgt_Tol

Rt_grp

Shade_tol

NL_seed

Salin_tol

Unsupervised

Preliminary results, do not cite (Sarr et al., in prep.)
Cluster Analysis Results (Dendrogram)

Supervised Classification

EROCIC BOUBAR PORGRA STEPAU BROTEC BRODIA DICCAN BRORUB EPHTOR MIRMUL LOTWRI GUTSAR OENPAL CUCFOE ACHHYM ELYELY ERALEH DATWRI BROCAT LOLPER ELYCAN ANDGER BRILON FUNCYN ISOACR OENELA LARTRI CELRET CERORB ACAGRE PROGLA EPHVIR ARIARI ALHMAU PLEJAM LYCPAL PLERIG BOTBAR ATRCAN EPHNEV MELOFF SALTRA CHLSPI BEBJUN ERACUR SPOAIR BACSAR BACSER MUHPOR PIPMIL ARTLUD LACSER FALPAR HESCOM SCHSCO SPOCRY SPOCON SPOFLE DIGCAL ENCFAR SPOGIG CONCAN EUTOCC APOCAN BOECYL CAREMO SCHAME SCHACU SCHPUN SALEXI PHRAUS SALGOO JUNTOR TYPLAT ECHCRU FRAVEL BACEMO BACSAL TAMRAM LEPLAT PLUSER SCHARU PASSMI CYNDAC DISSPI XANSTR AGRSTO ELEPAL ELEROS AGREXA SYMSUB POLMON POLVIR EQUARV EQUHYE HORJUB POAPRA PSESTR VERAME JUNARC MENARV MUHASP JUNNEV JUNCON JUNART JUNENS BROARV FESTHU SONASP SONOLE POROLE TAROFF PLALAN PLAMAJ

Samples

0

50

100

150

200

250

Distance

Rank variables

Weight variables, Indicator: Anaerobic

Weight variables, Indicator: Drought

Weight variables, Indicator: Height

Resemblance: D1 Euclidean distance

Sim8WtEuc10

c

a

i

d

b

e

j

g

f

h

Supervised

Preliminary results, do not cite (Sarr et al., in prep.)
Cluster Analysis Results

Supervised Classification

-200 -150 -100 -50 0 50 100 150

PCO1 (46.5% of total variation)

-150

-100

-50

0

50

100

150

P

C

O

2 (2

6.1%

of total variatio

n)

Rank variables

Weight variables, Indicator: Anaerobic

Weight variables, Indicator: Drought

Weight variables, Indicator: Height

Resemblance: D1 Euclidean distance

Sim8WtEuc10

c

a

i

d

b

e

j

g

f

h

ACAGRE

ACHHYM

AGREXA

AGRSTO

ALHMAU

ANDGER

APOCAN

ARIARI

ARTLUD

ATRCAN

BACEMO BACSAR

BACSAL

BACSER

BEBJUN

BOUBAR

BOTBAR

BOECYL

BROARV

BROCAT

BRODIA

BRILON

BRORUB

BROTEC

CAREMO

CELRET

CERORB

CHLSPI

CONCAN

CUCFOE

CYNDAC

DATWRI

DICCAN

DIGCAL

DISSPI

ECHCRU

ELYCAN

ELYELY

ELEPAL

ELEROS

ENCFAR

EPHNEV

EPHTOR

EPHVIR

EQUARV

EQUHYE

EROCIC

ERACUR

ERALEH

EUTOCC FALPAR

FESTHU

FRAVEL

FUNCYN

GUTSAR

HESCOM

HORJUB

ISOACR

JUNART

JUNARC

JUNCON

JUNENS JUNNEV

JUNTOR

LACSER

LARTRI

LEPLAT

LOLPER

LOTWRI

LYCPAL

MENARV

MELOFF

MIRMUL MUHASP

MUHPOR

OENELA

OENPAL

PASSMI

PHRAUS

PIPMIL

PLEJAM

PLALAN

PLAMAJ

PLERIG

PLUSER

PORGRA

POLMON

POROLE

POAPRA

POLVIR

PROGLA

PSESTR

SALEXI

SALGOO

SALTRA

SCHACU

SCHAME SCHARU

SCHPUN

SCHSCO

SONASP

SONOLE

SPOAIR SPOCRY SPOCONFLE

SPOGIG

STEPAU

SYMSUB

TAROFF

TAMRAM

TYPLAT

VERAME

XANSTR

NL_HT_mat

Anae_tol SMS_Veg

Drgt_Tol

Rt_grp

Shade_tol

NL_seed

Salin_tol

Supervised

Preliminary results, do not cite (Sarr et al., in prep.)
Guild Descriptions Guild A-Gutierrezia Guild

Guild A: This medium sized (n=16 

species) guild consists of low 

statured, relatively deep rooted, 

nonclonal shrubs, forbs, and 

graminoids with low flood 

tolerance and high drought 

tolerance. Characteristic species 

include Gutierrezia sarothrae, 

Stephanomeria pauciflora, 

Oenothera pallida, Achnatherum

hymenoides, Elymus elymoides,

and Bromus spp.

Gutierrezia sarothrae

Credit: Robert Sivinsky

Elymus elymoides

Credit: Thomas Stoughton

Guild A-Gutierrezia Guild

Preliminary results, do not cite (Sarr et al., in prep.)
Guild Descriptions Guild B-Brickellia Guild

Guild B: This medium sized (n=10 

species) guild is composed of a 

mixture of medium statured but 

deep rooted shrubs, robust forbs, 

and graminoids of medium to high 

drought tolerance and medium flood 

tolerance. Species include shrubs, 

such as Isocoma acradenia and 

Brickellia longifolia, rank forbs, such 

as Datura wrightii and Oenothera

elata, and graminoids, such as 

Andropogon gerardii, Elymus

canadensis, and Lolium perenne. 

Brickellia longifolia

Datura wrightii

Guild B-Brickellia Guild

Preliminary results, do not cite (Sarr et al., in prep.)
Guild Descriptions Guild C-Prosopis Guild

Guild C: This small (n=5 species) 

guild consists of large seeded, 

deep rooted, and robust trees 

and shrubs characterized by high 

drought tolerance, and low flood 

tolerance. Species include 

Prosopis glandulosa, Acacia 

greggii, Celtis reticulata, Cercis

orbiculata, and Larrea tridendata.

Prosopis glandulosa

Credit: Robert Sivinsky

Celtis reticulata

Credit:Zoya Akulova

Guild C-Prosopis Guild

Preliminary results, do not cite (Sarr et al., in prep.)
Guild Descriptions Guild D-Encelia Guild

Guild D: This large (n=30 species) 

guild consists of medium sized shrubs 

and graminoids characterized by high 

drought tolerance, and low flood 

tolerance. Species include shrubs 

such as Baccharis sarathroides, 

Fallugia paradoxa, Encelia farinosa, 

Ephedra spp., Lycium pallidum, and 

graminoids such as Achnatherum

hymenoides, Aristida arizonica, 

Bouteloua spp., and Sporobulus spp.

Sporobolus cryptandrus

Credit: Steve Matson

Encelia farinosa

Credit: Christopher L. Christie

Baccharis sarathroides

Guild D-Encelia Guild

Preliminary results, do not cite (Sarr et al., in prep.)
Guild Descriptions Guild E-Euthamia Guild

Guild E: This large (n=21 species) guild consists 

of robust trees, shrubs, forbs, and graminoids

characterized by low drought tolerance, high flood 

tolerance, a tendency toward vegetative 

reproduction, and smaller seed sizes. Notable 

species include the trees Salix goodingii, Tamarix

ramossissima, and Fraxinus velutina, shrubs such 

as Salix exigua, Euthamia occidentalis, Baccharis

emoryi, B. salicifolia,forbs such as Conyza

canadensis and Apocynum cannabinum, and 

robust graminoids such as Typha latifolia, 

Schoenoplectus spp., Phragmites australis, 

Schedonorus arundinaceus, and Carex emoryi.

Euthamia occidentalis

Credit: Aaron Arthur

Tamarix spp. 

Phragmites australis

Salix gooddingi

Credit: Neal Kramer

Guild E- Euthamia Guild

Preliminary results, do not cite (Sarr et al., in prep.)
Guild Descriptions Guild I-Agrostis Guild

Guild I: This large (n=20 species) guild 

consists of low statured forbs, and 

graminoids characterized by low drought 

tolerance, high flood tolerance, a strong 

tendency toward vegetative 

reproduction, and small seed sizes. 

Notable species include forbs such as

Veronica americana, Mentha arvensis, 

Equisetum spp. and a diverse suite of 

largely clonal graminoids, including 

Agrostis stolonifera, Eleocharis spp., 

Juncus spp., Polypogon monspeliensis, 

P. viridis, and Poa pratensis.

Mentha arvensis

Credit: Louis-M. Landry

Agrostis stolonifera 

Credit: Louis-M. Landry

Guild I- Agrostis Guild

Preliminary results, do not cite (Sarr et al., in prep.)
Guild Descriptions Guild J-Plantago Guild

Guild J: This medium sized (n=8 

species) guild is composed of a mixture 

of small statured, small seeded forbs 

and graminoids of intermediate drought 

and flood tolerance. Species include 

the forbs Plantago major, P. lanceolata, 

Taraxacum officinale, and Sonchus

spp., as well as the graminoids Festuca

thurberiana and Bromus arvensis.

Plantago major

Credit: Barry Breckling

Sonchus oleraceus

Credit: Neal Kramer

Guild J- Plantago Guild

Preliminary results, do not cite (Sarr et al., in prep.)
Guild Characteristics

-Gutierrezia Guild

-Brickellia Guild

-Prosopis Guild

- Encelia Guild

-Euthamia Guild

-Agrostis Guild

-Plantago Guild

Preliminary results, do not cite (Sarr et al., in prep.)
• A major challenge in most ecological monitoring efforts is high 

variation and low statistical power to detect change, due to low 

detection probabilities. This is especially true for many animal 

species, or spatially rare plant species.

• One solution is to increase sample numbers or increase the 

size of individual samples. Sample quadrat (1m2) vs. site (27m2)

• Other solutions include selection of indicator species (common 

species that predict rarer species) 

• Since our guilds contain between 5 and 30 plant species, guilds 

have the potential to increase detection probabilities

Application: Riparian Guilds As a MonitoringTool

Preliminary results, do not cite (Sarr et al., in prep.)
Application: Guilds As a Monitoring Tool

INDIVIDUAL SPECIES GUILDS

Preliminary results, do not cite (Sarr et al., in prep.)
Application: Riparian Guilds As a Modeling Tool

• Using logistic regression, we modeled 

the presence of each guild as a 

function of flow exceedance (amount of 

the time from 1985-2013 a site was 

inundated)

• We chose best models based using 

log-linear or polynomial equations

• Once the best models were selected, 

we used GIS to develop spatial grids of 

guild probability at a geomorphically

complex sandbar site (Kwagunt Marsh)

Forecasting Consequences of 

Alternate Flow Regimes

Preliminary results, do not cite (Sarr et al., in prep.)
Supervised Guilds Models

Guild A-Gutierrezia Guild Guild B-Brickellia Guild Guild C-Prosopis Guild Guild D-Encelia Guild

Guild E-Euthamia Guild Guild I-Agrostis Guild Guild J-Plantago Guild

Preliminary results, do not cite (Sarr et al., in prep.)
Supervised Guilds Models (no zeros)

Guild A-Gutierrezia Guild Guild B-Brickellia Guild Guild C-Prosopis Guild

Guild D-Encelia Guild

Guild E-Euthamia Guild Guild I-Agrostis Guild Guild J-Plantago Guild

Preliminary results, do not cite (Sarr et al., in prep.)
Application: Riparian Guilds As a Modeling Tool

 a

Kwagunt Marsh sandbar site. a) surface elevation, b) modeled exceedance probability (proportion of time that a given 

location is inundated, based on 1985-2013 flow data). 

Preliminary results, do not cite (Sarr et al., in prep.)
Modeled probabilities of occurrence for the guilds A-J from complete dataset(note that guilds F, G, and H had 

less than three species, and are not included). All probabilities are given in deciles from 0.0 to 0.9.

Guild A-Gutierrezia Guild Guild B-Brickellia Guild Guild C-Prosopis Guild Guild D-Encelia Guild

Guild E-Euthamia Guild Guild I-Agrostis Guild Guild J-Plantago Guild

Preliminary results, 

do not cite (Sarr et 

al., in prep.)
Modeled probabilities of occurrence for the supervised guilds A-J with empty samples excluded (note 

that guilds F, G, and H had less than three species, and are not included). All probabilities are given in 

deciles from 0.0 to 0.9.

Guild A-Gutierrezia Guild Guild B-Brickellia Guild Guild C-Prosopis Guild Guild D-Encelia Guild

Guild E-Euthamia Guild Guild I-Agrostis Guild Guild J-Plantago Guild

Preliminary results, 

do not cite (Sarr et 

al., in prep.)
Riparian Guilds in Grand Canyon-Initial Findings

• Classification process is challenging, and we need to settle 

on a best approach, but we are making great progress

• It appears to be a sound approach to aggregating species 

for riparian vegetation monitoring

• Can also have strong application to alternative modeling 

scenarios.

• Could possibly be improved by making linkages to 

theoretical and other forms of vegetation analysis
Monitoring Riparian Vegetation in Grand Canyon:

Next Steps

• Conduct modeling analyses of alternate flow scenarios 

(2015)

• Retrospective analysis of geomorphic and vegetation 

change on subsample of NAU sandbars (2015-2017)

• Conduct power analyses and floristic analyses of monitoring 

data (2015)

• Formalize monitoring protocol (2015-2016)

• Ask Emily more questions at her poster!
Questions?