A female cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum) in N. Sonora, Mexico, June 2022. Photo by Aaron Flesch, University of Arizona, Tucson, used with permission by USGS.
Pamela Nagler, Ph.D.
Expertise: Remote sensing applications in ecohydrology with a focus on scaling ground-based evapotranspiration (water use) measurements of plants in riparian ecosystems, their uplands and adjacent agriculture fields. Applications include mapping vegetation communities and phenological change in the Sonoran and Mojave Deserts and the transboundary region of northwestern Mexico and southwestern U.S.
Dr. Pamela Nagler’s interest in landscapes developed naturally through her experiences with a variety of lands and cultures throughout her early years. She first worked with USGS as a hydrological technician with the Water Resources Division, mentored by Drs. Jake Peters and Jamie Shanley. After obtaining a B.S. in Geography, Pamela interned with the late Barry Bishop (a member of the first American team to reach the summit of Mount Everest in 1963) at the National Geographic Society in Washington DC, where she was greatly influenced to pursue her passion for geography as a career. She then worked for the Solid Waste Division of the EPA followed by a couple of years with the Defense Mapping Agency. At the University of Maryland at College Park, Pamela earned an M.A. in Geography with an emphasis on Land Remote Sensing; her Advisor, Dr. Sam Goward, served as the Landsat Science Team Leader from 1992 and completed Landsat’s Enduring Legacy: 50 years in 2017. As his mentee, she gained experience and skills needed to address environmental applications using remote sensing tools. During her Master’s program, Pamela had a research assistantship with the USDA Agriculture Research Service under the guidance of Dr. Craig Daughtry, and helped develop techniques using hyperspectral data to distinguish soil from litter in the landscape. Pamela continued this research in Japan with a fellowship sponsored by NSF. Dr. Yoshio Inoue, her academic host at the Japan National Institute of Agro-Environmental Studies in 1996-1997, encouraged Pamela to return to the US to continue her academic studies. Pamela spent time in ten Asian countries before starting her Ph.D. research with Dr. Alfredo Huete at the University of Arizona in Tucson, AZ. Pamela's dissertation research used remote sensing tools to study environmental applications in the Colorado River delta in Mexico and her post-doctoral work with Dr. Edward Glenn was funded through a NASA grant. With direction from Ed Glenn, she studied seaweed productivity while living in Molokai, Hawaii, phytoremediation at DOE Legacy Mine sites on Navajo Nation near Monument Valley, and conservation and policy of the Colorado River Delta in the Borderlands of the U.S. and Mexico. Pamela received a PECASE Award at the White House with POTUS Obama in 2010, became a Kavli Fellow with the Academy of Sciences in 2011, and was internationally recognized by CSIRO in 2013. Pamela spent a year at CSIRO in their Land and Water Division in Adelaide, South Australia. Pamela serves students in three departments at the University of Arizona, including SNRE, SWES and more recently, Biosystems Engineering. She also serves on three journal Editorial Boards and as a Board Member of the FWS Sonoran Joint Venture.
Education and Certifications
Ph.D. - 2001, Soil, Water, and Environmental Science, University of Arizona, Tucson, AZ.
M.A. - 1997, Geography, University of Maryland. College Park, MD.
B.S. - 1989, Geography, University of Florida, Gainesville, FL.
Science and Products
Measuring Water Requirements Of Riparian Regions in the Southwestern U.S. Compared with Drylands in Australia
Using Imagery to Monitor Riparian and Upland Vegetation Along the San Pedro River, Arizona
Global Croplands and Their Water Use for Food Security in the Twenty-first Century
Remotely-sensed observations of restoration sites of the riparian corridor of the Colorado River Delta in Mexico, 2013-2022
Remotely-sensed observations of the unrestored riparian corridor of the Colorado River Delta in Mexico, 2019-2022
Random forest classification data developed from multitemporal Landsat 8 spectral data and phenology metrics for a subregion in Sonoran and Mojave Deserts, April 2013 – December 2020
Uncultivated plant water use (riparian evapotranspiration) and consumptive use data for selected areas of the Little Colorado River watershed on the Navajo Nation, Arizona
Colorado River Delta Project: A compilation of vegetation indices, phenology assessment metrics, and estimates of evapotranspiration for circular bird plots in the Colorado River delta between 2000-2020 (ver. 1.0)
Colorado River Project: A compilation of vegetation indices, phenology assessment metrics, estimates of evapotranspiration and change maps for five reaches between Hoover and Morelos Dams on the Lower Colorado River, for nearly the last two decades
Colorado River Project: Average growing season evapotranspiration and vegetation index remote-sensing data for the riparian corridor of the Colorado River Delta in Mexico from 2000-2020
Colorado River Delta Project: A compilation of vegetation indices, phenology assessment metrics, estimates of evapotranspiration and change maps for seven reaches of the delta's 150 km region, for nearly the last two decades
A female cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum) in N. Sonora, Mexico, June 2022. Photo by Aaron Flesch, University of Arizona, Tucson, used with permission by USGS.
Single species stand of nonnative tamarisk on the Lower Colorado River at Cibola National Wildlife Refuge, California
Single species stand of nonnative tamarisk on the Lower Colorado River at Cibola National Wildlife Refuge, California
Strategic restoration planning for land birds in the Colorado River Delta, Mexico
Crop water use dynamics over arid and semi-arid croplands in the lower Colorado River Basin
Supplying ecosystem services on US rangelands
A river basin spatial model to quantitively advance understanding of riverine tree response dynamics to water availability and hydrological management
Random forest classification of multitemporal Landsat 8 spectral data and P\phenology metrics for land cover mapping in the Sonoran and Mojave Deserts
Mapping vegetation index-derived actual evapotranspiration across croplands using the Google Earth Engine platform
Riparian plant evapotranspiration and consumptive use for selected areas of the Little Colorado River watershed on the Navajo Nation
Section 5: Remote sensing of vegetation in the riparian corridor of the Colorado River’s delta 2013-2018
Effect of restoration on plant greenness and water use in relation to drought in the riparian corridor of the Colorado River delta
Calibration of an evapotranspiration algorithm in a semiarid sagebrush steppe using a 3-ha lysimeter and Landsat normalized difference vegetation index data
Estimating actual evapotranspiration over croplands using vegetation index methods and dynamic harvested area
A tribute to Edward Perry Glenn (1947–2017), who created a legacy of environmental assessment and applications within hydrological processes
Science and Products
- Science
Measuring Water Requirements Of Riparian Regions in the Southwestern U.S. Compared with Drylands in Australia
Floodplain red gum forests are sites of high biodiversity in arid regions of south Australia. They depend on periodic floods from rivers, but dams and diversions have reduced flood frequencies, leading to deterioration of the trees. We determined the water requirements of red gum trees so environmental flows can be used to restore and maintain the forests. We used measurements of transpiration of...Using Imagery to Monitor Riparian and Upland Vegetation Along the San Pedro River, Arizona
The Upper San Pedro River is one of the few remaining undammed rivers that maintain a vibrant riparian ecosystem in the southwest. However, its riparian forest is threatened by diminishing groundwater and surface water inputs, due to either changes in watershed characteristics such as changes in riparian and upland vegetation, or human activities such as regional groundwater pumping. We used...Global Croplands and Their Water Use for Food Security in the Twenty-first Century
Global climate change is putting unprecedented pressure on global croplands and their water use, vital for ensuring future food security for the world's rapidly expanding human population. The end of the green green revolution (productivity per unit of land) era has meant declining global per capita agricultural production requiring immediate policy responses to safeguard food security amidst glob - Data
Remotely-sensed observations of restoration sites of the riparian corridor of the Colorado River Delta in Mexico, 2013-2022
These data were compiled for evaluating plant water use, or river-reach level evapotranspiration (ET) data, in the riparian corridor of the Colorado River delta as specified under Minute 319 of the 1944 Water Treaty. Additionally, these data were compiled for evaluating restoration-level data in Reach 2 and Reach 4, as specified under Minute 323 of the 1944 Water Treaty. Objectives of our study weRemotely-sensed observations of the unrestored riparian corridor of the Colorado River Delta in Mexico, 2019-2022
These data were compiled for evaluating plant water use, or river-reach level evapotranspiration (ET) data, in the unrestored riparian corridor of the Colorado River delta as specified under Minute 319 of the 1944 Water Treaty. Additionally, these data were compiled for evaluating restoration-level data in Reach 2 and Reach 4, as specified under Minute 323 of the 1944 Water Treaty. Objectives of oRandom forest classification data developed from multitemporal Landsat 8 spectral data and phenology metrics for a subregion in Sonoran and Mojave Deserts, April 2013 – December 2020
These data were compiled for the creation of a continuous, transboundary land cover map of Bird Conservation Region 33, Sonoran and Mojave Deserts (BCR 33). Objective(s) of our study were to, 1) develop a machine learning (ML) algorithm trained to classify vegetation land cover using remote sensing spectral data and phenology metrics from 2013-2020, over a large subregion of the Sonoran and MojaveUncultivated plant water use (riparian evapotranspiration) and consumptive use data for selected areas of the Little Colorado River watershed on the Navajo Nation, Arizona
These data were compiled to provide Fred Phillips Consultants with an estimate of river and stream vegetation (riparian) water use within the Little Colorado River (LCR) Watershed in Arizona, specifically providing an estimate of riparian plant area ET (mm/day and in mm/year) for actual remotely-sensed estimates of ETa and CU for at least one year of data (i.e., 2020). Objectives of our study wereColorado River Delta Project: A compilation of vegetation indices, phenology assessment metrics, and estimates of evapotranspiration for circular bird plots in the Colorado River delta between 2000-2020 (ver. 1.0)
These data were compiled to understand the effects of riparian vegetation health on local abundance and species diversity of land birds. The primary objective of our study was to to determine the effects of riparian restoration on birds in the Colorado River delta. These tabular data represent vegetation indices and evapotranspiration (ET) data at varying spatial scales that correspond to avian usColorado River Project: A compilation of vegetation indices, phenology assessment metrics, estimates of evapotranspiration and change maps for five reaches between Hoover and Morelos Dams on the Lower Colorado River, for nearly the last two decades
These raster and tabular data were compiled to develop time series data of the lower Colorado River (LCR) vegetation greenness, water use, and phenology since the year 2000. An objective of our study was to evaluate short and long-term effects of drought and biocontrol on LCR riparian and aquatic ecosystems south of Hoover Dam. These data represent spatially explicit average Enhanced Vegetation InColorado River Project: Average growing season evapotranspiration and vegetation index remote-sensing data for the riparian corridor of the Colorado River Delta in Mexico from 2000-2020
These data were compiled for evaluating river-reach level plant water use, or evapotranspiration (ET), and vegetation greenness, or Normalized Difference Vegetation Index (NDVI), in the riparian corridor of the Colorado River delta as specified under Minute 319 of the 1944 Water Treaty. The seven reach areas from the Northerly International Boundary (NIB) to the end of the delta at the Sea of CortColorado River Delta Project: A compilation of vegetation indices, phenology assessment metrics, estimates of evapotranspiration and change maps for seven reaches of the delta's 150 km region, for nearly the last two decades
These data were compiled for monitoring riparian zone trends and changes in the Lower Colorado Delta as part of the Minute 139 of the 1944 Water Treaty between the United States and Mexico. The quality and quantity of the Delta's riparian and aquatic ecosystems have been dramatically reduced over the past century, due largely to significant alterations to natural hydrologic and sediment regimes. T - Multimedia
Cactus ferruginous pygmy-owl in N. Sonora, Mexico
A female cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum) in N. Sonora, Mexico, June 2022. Photo by Aaron Flesch, University of Arizona, Tucson, used with permission by USGS.
A female cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum) in N. Sonora, Mexico, June 2022. Photo by Aaron Flesch, University of Arizona, Tucson, used with permission by USGS.
A single species stand of nonnative tamariskSingle species stand of nonnative tamarisk on the Lower Colorado River at Cibola National Wildlife Refuge, California
Single species stand of nonnative tamarisk on the Lower Colorado River at Cibola National Wildlife Refuge, California
- Publications
Filter Total Items: 77
Strategic restoration planning for land birds in the Colorado River Delta, Mexico
Ecological restoration is an essential strategy for mitigating the current biodiversity crisis, yet restoration actions are costly. We used systematic conservation planning principles to design an approach that prioritizes restoration sites for birds and tested it in a riparian forest restoration program in the Colorado River Delta. Restoration goals were to maximize the abundance and diversity ofAuthorsJoanna Grand, Timothy D Meehan, William V. Deluca, Julia Morton, Jennifer Pitt, Alejandra Calvo-Fonseca, Chris Dodge, Martha Gómez-Sapiens, Eduardo González Sargas, Osvel Hinojosa-Huerta, Pamela L. Nagler, Carlos Restrepo-Giraldo, Patrick B. Shafroth, Stefanny Villagomez-Palma, Chad B WilseyCrop water use dynamics over arid and semi-arid croplands in the lower Colorado River Basin
Numerous studies have evaluated the application of Remote Sensing (RS) techniques for mapping actual evapotranspiration (ETa) using Vegetation-Index-based (VI-based) and surface energy balance methods (SEB). SEB models computationally require a large effort for application. VI-based methods are fast and easy to apply and could therefore potentially be applied at high resolution; however, the accurAuthorsNeda Abbasi, Hamideh Nouri, Pamela L. Nagler, Kamel Didan, Sattar Chavoshi Borujeni, Armando Barreto-Muñoz, Christian Opp, Stefan SiebertSupplying ecosystem services on US rangelands
Rangelands comprise 40% of the conterminous United States and they supply essential ecosystem services to society. A scenario assessment was conducted to determine how accelerating biophysical and societal drivers may modify their future availability. Four scenarios emerged: two may maintain rural communities by sustaining the prevailing ecosystem service of beef cattle production, and two may traAuthorsDavid D. Briske, Steven R. Archer, Emily Burchfield, William Burnidge, Justin D. Derner, Hannah Gosnell, Jerry Hatfield, Clare E. Kazanski, Mona Khalil, Tyler J. Lark, Pamela L. Nagler, Osvaldo E. Sala, Nathan F. Sayre, Kimberly R. Stackhouse-LawsonA river basin spatial model to quantitively advance understanding of riverine tree response dynamics to water availability and hydrological management
Ecological condition continues to decline in arid and semi-arid river basins globally due to hydrological over-abstraction combined with changing climatic conditions. Whilst provision of water for the environment has been a primary approach to alleviate ecological decline, how to accurately monitor changes in riverine trees at fine spatial and temporal scales, remains a substantial challenge. ThisAuthorsTanya M. Doody, Sicong Gao, Willem Vervoot, Jodie Pritchard, Michah Davies, Martin Nolan, Pamela L. NaglerRandom forest classification of multitemporal Landsat 8 spectral data and P\phenology metrics for land cover mapping in the Sonoran and Mojave Deserts
Geospatial data and tools evolve as new technologies are developed and landscape change occurs over time. As a result, these data may become outdated and inadequate for supporting critical habitat-related work across the international boundary in the Sonoran and Mojave Deserts Bird Conservation Region (BCR 33) due to the area’s complex vegetation communities and the discontinuity in data availabilAuthorsMadeline Melichar, Kamel Didan, Armando Barreto-Muñoz, Jennifer N. Duberstein, Eduardo Jiménez Hernández, Theresa Crimmins, Haiquan Li, Myles B. Traphagen, Kathryn A. Thomas, Pamela L. NaglerMapping vegetation index-derived actual evapotranspiration across croplands using the Google Earth Engine platform
Precise knowledge of crop water consumption is essential to better manage agricultural water use, particularly in regions where most countries struggle with increasing water and food insecurity. Approaches such as cloud computing and remote sensing (RS) have facilitated access, process, and visualization of big geospatial data to map and monitor crop water requirements. To find the most reliable VAuthorsNeda Abbasi, Hamideh Nouri, Kamel Didan, Armando Barreto-Muñoz, Sattar Chavoshi Borujeni, Christian Opp, Pamela L. Nagler, Prasad Thenkabail, Stefan SiebertRiparian plant evapotranspiration and consumptive use for selected areas of the Little Colorado River watershed on the Navajo Nation
Estimates of riparian vegetation water use are important for hydromorphological assessment, partitioning within human and natural environments, and informing environmental policy decisions. The objectives of this study were to calculate the actual evapotranspiration (ETa) (mm/day and mm/year) and derive riparian vegetation annual consumptive use (CU) in acre-feet (AF) for select riparian areas ofAuthorsPamela L. Nagler, Armando Barreto-Muñoz, Ibrahima Sall, Matthew R. Lurtz, Kamel DidanSection 5: Remote sensing of vegetation in the riparian corridor of the Colorado River’s delta 2013-2018
This remote sensing section is based on Nagler et al. (in preparation for the journal Hydrological Processes) and is a summary of the USGS preliminary findings to date. This report documents the changes in green foliage density (greenness) as measured by satellite vegetation index (VI) data and corresponding evapotranspiration (ET) in the riparian corridor of the Colorado River delta associated wiAuthorsPamela L. Nagler, Armando Barreto-Munoz, Christopher J. Jarchow, Kamel DidanEffect of restoration on plant greenness and water use in relation to drought in the riparian corridor of the Colorado River delta
Revitalization of the Colorado River delta riparian corridor and increasing riparian plant greenness and water use may be accomplished by added water and restoration efforts to offset declines measured since 2000 by Landsat. We use the two-band Enhanced Vegetation Index (EVI2; a proxy for greenness) and evapotranspiration (ET, mm/day) using EVI2 and potential ET(ETo) from Yuma Valley. We assess ifAuthorsPamela L. Nagler, Ibrahima Sall, Armando Barreto-Muñoz, Martha Gómez-Sapiens, Hamideh Nouri, Sattar Chavoshi Borujeni, Kamel DidanCalibration of an evapotranspiration algorithm in a semiarid sagebrush steppe using a 3-ha lysimeter and Landsat normalized difference vegetation index data
In arid and semiarid environments, evapotranspiration (ET) is the primary discharge component in the water balance, with potential ET exceeding precipitation. For this reason, reliable estimates of ET are needed to construct accurate water budgets in these environments. Remote sensing affords the ability to provide fast, accurate, field-scale ET estimates, but these methods have largely been restrAuthorsChristopher J. Jarchow, William J. Waugh, Pamela L. NaglerEstimating actual evapotranspiration over croplands using vegetation index methods and dynamic harvested area
Advances in estimating actual evapotranspiration (ETa) with remote sensing (RS) have contributed to improving hydrological, agricultural, and climatological studies. In this study, we evaluated the applicability of Vegetation-Index (VI) -based ETa (ET-VI) for mapping and monitoring drought in arid agricultural systems in a region where a lack of ground data hampers ETa work. To map ETa (2000–2019)AuthorsNeda Abbasi, Hamideh Nouri, Kamel Didan, Armando Barreto Munez, Sattar Chavoshi Borujeni, Hamidreza Salemi, Christian Opp, Stefan Siebert, Pamela L. NaglerA tribute to Edward Perry Glenn (1947–2017), who created a legacy of environmental assessment and applications within hydrological processes
This issue of Hydrological Processes is dedicated to Dr. Edward P. Glenn, a frequent contributor to the journal, who suddenly passed away in late 2017. The articles within this volume are by a number of his former co-authors and others who have been greatly influenced by his professional work on hydrological processes.AuthorsPamela L. Nagler, Matthew K Chew, Kevin Fitzsimmons, Charles van Riper III - News