Standing between Life and Extinction Ethics and Ecology of Conserving Aquatic Species in North American Deserts
edited by David L. Propst, Jack E. Williams, Kevin R. Bestgen and Christopher W. Hoagstrom, foreword by Tom Udall
University of Chicago Press, 2021
Cloth: 978-0-226-69433-7 | Paper: 978-0-226-69447-4 | Electronic: 978-0-226-69450-4
DOI: 10.7208/chicago/9780226694504.001.0001
ABOUT THIS BOOKAUTHOR BIOGRAPHYREVIEWSTABLE OF CONTENTS

ABOUT THIS BOOK

North American deserts—lands of little water—have long been home to a surprising diversity of aquatic life, from fish to insects and mollusks. With European settlement, however, water extraction, resource exploitation, and invasive species set many of these native aquatic species on downward spirals. In this book, conservationists dedicated to these creatures document the history of their work, the techniques and philosophies that inform it, and the challenges and opportunities of the future.

A precursor to this book, Battle Against Extinction, laid out the scope of the problem and related conservation activities through the late 1980s. Since then, many nascent conservation programs have matured, and researchers have developed new technologies, improved and refined methods, and greatly expanded our knowledge of the myriad influences on the ecology and dynamics of these species. Standing between Life and Extinction brings the story up to date. While the future for some species is more secure than thirty years ago, others are less fortunate. Calling attention not only to iconic species like the razorback sucker, Gila trout, and Devils Hole pupfish, but also to other fishes and obscure and fascinating invertebrates inhabiting intermittent aquatic habitats, this book explores the scientific, social, and political challenges of preserving these aquatic species and their habitats amid an increasingly charged political discourse and in desert regions characterized by a growing human population and rapidly changing climate.

AUTHOR BIOGRAPHY

David L. Propst is adjunct professor and associate curator in the Department of Biology and Museum of Southwestern Biology at the University of New Mexico. He is coauthor of Fish of the Rockies. He lives in Albuquerque, NM. Jack E. Williams is emeritus senior scientist for Trout Unlimited. Most recently, he is coeditor of Trout and Char of the World. He lives in Oregon’s Rogue River Valley. Kevin R. Bestgen is a senior research scientist in the Department of Fish, Wildlife, and Conservation Biology as well as director of the Larval Fish Laboratory at Colorado State University. He lives in Fort Collins, CO. Christopher W. Hoagstrom is professor in the Department of Zoology at Weber State University. He lives in Ogden, UT.

REVIEWS

“This book should appeal to anyone broadly interested in conservation and management of water resources, and specifically to conservation scientists, natural resource managers, and fish biologists. There are strong historical threads woven throughout the chapters, and it serves both as a tribute to pioneering legends of early desert fish conservation and a synthesis of ongoing work that reveals successes, failures, and challenges in the face of human populations expanding into arid regions, the increasing conflicts over exploitation of water and land, and the overriding and worsening impacts of human-mediated climate change. The breadth of topics presented and synthesis of complex research outcomes as applied to conservation challenges are impressive. A valuable addition to the conservation literature that will be read widely and cited extensively.”
— Michael S. Parker, Southern Oregon State University

"Many see the arid lands of western North America as a stretch of dry, flyover territory, the setting for shoot-'em-up cowboy movies and the venue for arguments over water rights. This volume edited by Propst, Williams, Bestgen, and Hoagstrom will completely shatter those supercilious projections. Conservation of desert fishes was introduced in Battle against Extinction,edited by W. L. Minckley and James Deacon. A group of passionate experts in biodiversity, conservation, history, hydrology, and politics expand the subject in this excellent exploration of the land-water-bioconservation ethic for both sides of the RioGrande. Adding to its attraction as a textbook, a deep dive by researchers will reward with new lines of inquiry. The photographs are striking and instructive, tables are crisp, and the writing style is inviting. In particular, candid photographs of habitats and workers in the field offer readers an authentic view of the people, topics, and challenges the volume addresses. The index is extensive, and each chapter includes its own list of cited literature. This reviewer could not ask for more in a textbook for use in advanced classes, or as a reference work to be added to his personal bookshelf. . . . Highly recommended"
— Choice

TABLE OF CONTENTS

- Jack E. Williams, David L. Propst
DOI: 10.7208/chicago/9780226694504.003.0001
[native fish species;arid-land aquatic systems;conservation;Battle Against Extinction;climate change;Desert Fishes Council;Endangered Species Act]
Water was a critical fuel for post-World War II economic and population growth in the North American west and its appropriation for human use brought new challenges to aquatic organisms that had evolved in harsh environments but were little prepared for extensive alteration of fragile arid-land aquatic systems. There was little regard for native fish species if they had no immediate and tangible worth to humans. But an increasing awareness by resource managers and academics of the plight of this vanishing fauna spawned the Desert Fishes Council in 1969. With passage of the Endangered Species Act in 1973, additional impetus for conservation of native aquatic organisms was provided. Published in 1991, The Battle Against Extinction summarized progress and issues in arid-land native fish conservation through about 1990. Since then, new technologies, evolving strategies, and a changing climate provide new opportunities and exacerbate lingering issues, including uncertain political support for conservation. How persistent conservation problems are addressed and resolved will determine the fate of numerous arid-land aquatic organisms. (pages 3 - 12)
This chapter is available at:
    University of Chicago Press
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- Robert J. Edwards
DOI: 10.7208/chicago/9780226694504.003.0002
[Carl Leavitt Hubbs;Robert Rush Miller;W.L. Minckley;James E. Deacon;Clark Hubbs;Robert J. Behnke;Edwin Philip Pister;desert fish conservation]
Each field has its pioneers, and the field of desert fish conservation is no exception. Efforts to conserve aquatic life in the desert have been fueled equally by the ecological understandings developed by science and conservation actions directed by firmly held ethical beliefs. A few individuals are capable of combining scientific knowledge and conservation ethics into an undeniable passion that becomes contagious. These pioneering giants marveled at the ability of certain species to survive in seemingly harsh environments and, when necessary, mounted a vigorous defense when outside forces threatened their survival. This chapter traces the careers of a small handful of highly dedicated and influential scientists who recognized the value of desert fishes and came to their aid at a time when few cared for, or even knew of, such species. They saved species and habitats while influencing so many to follow in their footsteps. In this chapter, the legacies of eight giants in the field desert fish conservation are honored, and it is hoped that through these biographies they will continue to inspire new professional, ethical, committed warriors to join the battle against extinction. (pages 13 - 36)
This chapter is available at:
    University of Chicago Press
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- Christopher W. Hoagstrom, Derek D. Houston, Norman Mercado-Silva
DOI: 10.7208/chicago/9780226694504.003.0003
[area of endemism;fish lineages;desert region;biogeography;diversity;faunal filters]
North America hosts 336 lineages of fishes restricted to the desert region. These desert endemics have diverse distributions from large river basins to small springs. A major biogeographic boundary divides the region into: 1) Northern Great Basin-Colorado Plateau and 2) Southern Desert-Eastern Steppes. These subdivisions are themselves divisible into 13 and 17 areas of endemism, respectively, each with a unique assemblage of endemics. Eighty-two percent of endemics are restricted to single areas and no lineage occupies more than five. The few widespread lineages that occupy more than one area reflect instances of inter-area drainage connections, sometimes prehistoric. Estimates of diversification times indicate asynchronous evolution, with endemics arising at various times across the region over the last ~23 My. A conceptual model of faunal assembly is used to illustrate how areas of endemism, through faunal filtering, become centers of survival, with many also becoming centers of origin and centers of accumulation for desert-fish diversity. Collective conservation necessitates efforts to preserve and restore essential habitats in all areas of endemism. (pages 37 - 68)
This chapter is available at:
    University of Chicago Press
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- Peter B. Moyle
DOI: 10.7208/chicago/9780226694504.003.0004
[alien fishes;native fishes;eradication and control;reconciliation ecology]
Alien fishes and invertebrates dominate most aquatic ecosystems in the Southwest, as part of novel ecosystems. Thus, their presence will continue to be a problem for native fishes. In addition, most alien fishes enjoy a symbiotic relationship with people in which both species benefit. This means we have to learn to live with them, battling them where necessary, but also finding ways to allow native and alien fishes to coexist. Sometimes the native fishes become the invaders, providing additional challenges. Understanding these complexities is necessary to know when it is worth putting scarce resources into eradication and control programs and when it is better to find ways to reconcile environmental management to favor natives, despite the presence of aliens. The Battle Against Extinction is still being waged but Reconciliation Ecology may provide a more realistic future path for most native fishes. (pages 69 - 78)
This chapter is available at:
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- María de Lourdes Lozano-Vilano, Armando J. Contreras-Balderas, Gorgonio Ruiz-Campos, María Elena García-Ramírez
DOI: 10.7208/chicago/9780226694504.003.0005
[Mexico;freshwater fish;threatened taxa;aquatic habitats;Mexican laws;spring drying;Cyprinidon]
We present new information regarding the status of some endemic freshwater fishes of México from eight states and 24 localities. From earlier descriptions summarized in 1991, two fishes were known extinct, but by 2017, the total increased to 15 taxa either extinct or gone from the wild and present only in captive populations. Species in the genus Cyprinodon are the most threatened taxa at the sites we visited. Main reasons for rapid declines or extinctions are springs drying due to increased water consumption by domestic, industrial, and agricultural practices, and negative effects of nonnative species. The destruction of aquatic habitats occurs everywhere in México and requires more protected areas for aquatic organisms. The survival of this group of animals, especially in arid zones, is in jeopardy of disappearing forever. The number of species declining or extinct continues to rise, increasing the importance of protection by Mexican laws. (pages 79 - 88)
This chapter is available at:
    University of Chicago Press
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- Jack E. Williams, Donald W. Sada
DOI: 10.7208/chicago/9780226694504.003.0006
[extinction;extirpation;habitat degradation;nonnative species;endangered desert fishes;aquatic invertebrates]
One of the primary priorities of conservation is to prevent extinctions. Thirty-three fishes and 23 aquatic invertebrates are recorded as recently extinct within the desert and adjacent regions of the United States and Mexico. Additionally, five fishes are listed as extinct in the wild. The process of extinction often begins with habitat degradation or other disturbance that diminishes local populations or causes local extirpations that lead to the entire species or subspecies being more susceptible to loss. Extinction itself was often linked to some catastrophic change in water supply, such as water diversion or spring failure due to over-withdrawal of groundwater. Introductions of nonnative species that may prey on, compete with, or hybridize with native species, were more common in extinction of desert fishes than for aquatic invertebrates. Detailed obituaries are provided for the Amistad gambusia, Nevada pyrg, Julimes tryonia, Tecopa pupfish, poolfishes of the genus Empetrichthys, and the Alvord cutthroat trout. Increasing numbers of endangered and extinct species are a cautionary account about our own future. The question for humans is whether the warning signs will be obeyed or whether society proceeds headlong into a future where our own species may be at risk. (pages 89 - 106)
This chapter is available at:
    University of Chicago Press
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- Bradley H. Udall
DOI: 10.7208/chicago/9780226694504.003.0007
[climate change;Colorado River;Rio Grande;water management;infrastructure;dams]
The two major rivers of the Southwest United States and Mexico, the Colorado and the Rio Grande, were fundamentally and irretrievably altered during the 20th century. Massive dam construction in both basins provided new water supplies for agricultural and municipal growth throughout the region. As water needs increased and infrastructure grew to meet these needs, water management laws and agreements also increased in number and complexity. Water demand in both basins grew to equal supplies and now the Colorado River fails to reach the ocean, and the Rio Grande dries in places it historically did not. Natural ecosystems have suffered because of water diversions and both basins now contain endangered aquatic and riparian species. Water management is complex and difficult to modify to meet changing requirements. Climate change will continue to impact both rivers by reducing flows as air temperatures warm, further reducing the ability of these systems to support sustainable supplies for people and ecosystems. (pages 109 - 123)
This chapter is available at:
    University of Chicago Press
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- Gary P. Garrett, Megan G. Bean, Robert J. Edwards, Dean A. Hendrickson
DOI: 10.7208/chicago/9780226694504.003.0008
[aquifer depletion;aquatic habitat degradation;functional watersheds;landowner participation;Native Fish Conservation Areas;Texas]
Desert ecosystems are particularly susceptible to anthropogenic influences. This is especially true where limited water resources can be impaired by water mining and concomitant depletion of aquifers. Herein, the decline of aquatic habitats throughout the Chihuahuan Desert of Texas is discussed and observations on relationships among declining aquifer levels, aquatic habitat degradation, and status of native fishes are presented. Examples from the Big Bend reach of the Rio Grande, Balmorhea Springs Complex, Pecos River, and Devils River reveal a decline in distribution and abundance of native fishes. Ongoing and impending land-use practices and increased demands on groundwater and surface water resources point to future reductions. However, activities are underway that represent a source of optimism for conservation of aquatic habitats and native fishes. Native Fish Conservation Areas are being established to enhance management of desert ecosystems to restore and maintain functional watersheds, conserve aquatic habitats, and support native fishes. Increased landowner awareness of the value of cooperative conservation of aquatic resources and their inclusion in management decisions are critically important, particularly in Texas where the majority of land is privately owned. Ultimately, archaic Texas water laws need revision and reformulation if desert aquatic systems are to be restored and preserved. (pages 125 - 136)
This chapter is available at:
    University of Chicago Press
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- Jonathan T. Overpeck, Scott A. Bonar
DOI: 10.7208/chicago/9780226694504.003.0009
[aquatic systems;climate change;drought;wildfire;adaptive management;desert fish species;extinction]
Anthropogenic climate change is already apparent in southwest North America, with growing consequences for the region’s aquatic systems. Air and water temperatures are increasing, and there is high confidence that this will continue. Future precipitation change is less certain, but observations indicate drying is most likely, particularly given the evaporative pressures of warmer temperatures. Longer and more severe droughts are also likely and may last decades. The region’s aquatic systems will experience depleted groundwater and continued drying of surface water, and more erosion due to increases in forest mortality and severe wildfire. Warming will challenge many species, just as the decreases of streamflow will reduce available habitat. Shifts in seasonal stream hydrographs will likely change aquatic ecosystem dynamics. Management options for addressing climate change impacts include protecting flows, creation of fish refugia, elimination of non-climatic stresses, forest management for water and erosion control, incorporation of climate considerations in species plans, and most importantly, engagement to prioritize climate change action among the public. Given the uncertainties associated with anticipating place-based climate change impacts, adaptive management will be needed. (pages 137 - 152)
This chapter is available at:
    University of Chicago Press
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- Kate S. Boersma, David A. Lytle
DOI: 10.7208/chicago/9780226694504.003.0010
[aquatic invertebrates;Arizona;climate change;novel drought regimes;catastrophic disturbance;community trajectories;functionally important taxa]
Aquatic invertebrates inhabiting arid-land streams possess diverse adaptations to withstand cycles of drying and flooding. However, anthropogenic water withdrawals and climate change are modifying the historical hydrological variability, increasing the frequency, intensity, and duration of droughts. These novel drought regimes act as catastrophic disturbances that restructure aquatic invertebrate communities and generate novel community trajectories. Here, we use a case study from a stream in southeastern Arizona to demonstrate how taxa differ in their capacity to survive severe droughts and that these different responses have consequences for ecosystem ecology. We posit that, in addition to changes caused by direct loss of taxa due to drought, other widespread community changes may be indirect consequences of the disappearance of a few particularly vulnerable, functionally important taxa. Focusing conservation efforts on these key taxa should be a component of mitigation and restoration efforts and may increase the overlap of invertebrate and fish conservation strategies. (pages 153 - 166)
This chapter is available at:
    University of Chicago Press
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- Brandon Albrecht, Ron Kegerries, Ron Rogers, Paul Holden
DOI: 10.7208/chicago/9780226694504.003.0011
[desert fishes;Colorado River;nonnative fish control;habitat complexity;nonnative species;public outreach]
Native fishes of desert-aquatic ecosystems have been dramatically impacted by nonnative species. Over time, habitat modification and degradation set the stage for the influx of many nonnative taxa. Traditionally, nonnative-fish control has meant attempting to eliminate every individual from habitats of interest. In larger systems, this has proven impossible, and managers have sought ways for nonnatives and natives to coexist by reducing stressors on natives. This chapter describes the nonnative-fish dilemma, lessons learned, and possible pathways for remediation, with a focus on the Colorado River basin. It is argued that greater habitat complexity and more natural flow regimes help natives and nonnatives coexist and concludes that a multiplicity of tools and techniques, along with improved education and public outreach, remain important for conserving native fishes. (pages 167 - 180)
This chapter is available at:
    University of Chicago Press
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- Matthew E. Andersen, James E. Brooks
DOI: 10.7208/chicago/9780226694504.003.0012
[Endangered Species Act;endangered species;habitat protection;recovery planning;collaborative approaches]
The Endangered Species Act (ESA) has been a powerful tool for species conservation since its passage. Protections from the ESA have reduced the likelihood of extinctions for many species, yet conservation actions have rarely led to full recovery for aquatic species. Expectations for ESA effectiveness are challenged by competing conservation needs among rare species, competition for resources such as water, and funding needs that can be rarely met. The most comprehensive of any species protection legislation in the world, the ESA is vilified by some as an example of federal overreach because its habitat protection provisions may slow development or appear in conflict with state rights. Habitat protection provisions of the ESA are particularly important to desert fish conservation, especially when a species is restricted to a single or few habitats. ESA implementation options have evolved over its 45-year history to be more flexible, resulting in collaborative approaches among agencies, stakeholders, and private individuals. If ESA implementation is to continue to support desert fish conservation, it seems likely that flexible, collaborative approaches will be necessary; however, it is also likely that future drought and water shortages will be obstacles to future conservation efforts. (pages 183 - 198)
This chapter is available at:
    University of Chicago Press
    https://academic.oup.com/chica...

- Adam E. Cohen, Dean A. Hendrickson, Gary P. Garrett
DOI: 10.7208/chicago/9780226694504.003.0013
[biogeographical studies;museum specimens;historical collections;Fishes of Texas Project;conservation decision-making]
Specimen collections are critically important for modern ecological, evolutionary, and biogeographical studies and are increasingly aiding conservation decision-making. The information collections contained in the form of specimen-backed occurrences, field notes, and images can provide insights and guidance for researchers and resource managers and serve as a verifiable baseline representing historical conditions. The Fishes of Texas Project is a regional, quality-controlled, database of museum specimens compiled from many collections, and an online user interface allowing users to view, map, and download data. It has enhanced conservation decision-making for aquatic species in Texas and might serve as a template for similar regional projects. (pages 199 - 206)
This chapter is available at:
    University of Chicago Press
    https://academic.oup.com/chica...

- Thomas F. Turner, Thomas E. Dowling, Trevor J. Krabbenhoft, Megan J. Osborne, Tyler J. Pilger
DOI: 10.7208/chicago/9780226694504.003.0014
[desert fishes;conservation genetics;next-generation DNA sequencing;Bayesian statistics;bioinformatics;RADseq.;environmental DNA]
At its core, conservation genetics aims to characterize genetic diversity in space and time, infer processes that change diversity, and use this information to prescribe actions that maintain and enhance diversity and self-sustainability of imperiled species. The field of conservation genomics, fueled by rapid advances in DNA sequencing and genotyping technologies, offers considerable promise for informing conservation of desert fishes. A whole-genome perspective permits deeper insight into lineage identity, roles for natural and artificial selection for shaping diversity, and scope for response to environmental change. Similarly, high-throughput genotyping technology allows unique identification of thousands of individuals at low cost, thereby enabling genetic monitoring programs that explicitly link demographic and genetic processes in recovery planning and implementation. Dense temporal and spatial sampling enhances accuracy and precision of key metrics like genetic effective population size and effective migration rates. Rapid developments in epigenetics and remote sensing will continue to revolutionize the field. Yet, as new technology is applied to conservation problems, it is important to be mindful of limitations and pitfalls. Interpretation based on principles of ecological, evolutionary, and genetic theory is essential when translating findings to action to benefit desert fishes. (pages 207 - 224)
This chapter is available at:
    University of Chicago Press
    https://academic.oup.com/chica...

- Peter N. Reinthal, Heidi Blasius, Mark Haberstich
DOI: 10.7208/chicago/9780226694504.003.0015
[monitoring;aquatic ecosystems;desert fish fauna;aquatic conservation;Aravaipa Creek]
Since publication of Battle Against Extinction in 1991 there have been substantial changes to the natural and anthropogenic landscapes of the desert southwest. Environmental impacts have accelerated with increasing human populations but, unfortunately, scant attention is given to long-term changes in natural aquatic biotas. Beginning in 1963, W.L. Minckley, colleagues, and students monitored and studied fish assemblages of Aravaipa Creek, Arizona. Minckley’s monitoring efforts continued until his death in 2001 and since then by the authors of this chapter. This represents the longest continuous record of abundance and distribution of any fish assemblage in the region. Considerable scientific information has been gained from these efforts and forms the basis for much that is known about several iconic native desert fishes. These data provide a comparative baseline to characterize responses to biotic and abiotic events and modifications of Aravaipa Creek. Data obtained provide critical information on fish assemblage dynamics, species ecology, impacts of human-induced alterations and management, and insights on potential consequences of global warming. Herein are presented results from 54 years of Aravaipa Creek fish monitoring and illustration of how fish populations respond to changes in the Aravaipa catchment. (pages 225 - 238)
This chapter is available at:
    University of Chicago Press
    https://academic.oup.com/chica...

- Mark C. Stone, Ryan R. Morrison
DOI: 10.7208/chicago/9780226694504.003.0016
[river engineering;floodplain development;dams and diversions;stream restoration;environmental flows;dynamic equilibrium;natural flow regime]
Watersheds, rivers, and floodplains in desert environments have been dramatically altered to meet human needs. Modifications include river engineering projects, floodplain development, dams and diversions, and watershed development, amongst others. In the southwestern United States (the Southwest), the exploitation of rivers for human needs has enabled a remarkable level of economic and population growth over the past century. The implications of these development pressures, however, have been profound for aquatic ecosystems. Modifications to hydrologic and geomorphic processes have contributed to population decline, endangerment, extirpation, and in several cases extinction of native species. This chapter provides a synopsis of the recent history of watershed, river, and floodplain development in the Southwest. Using examples from across the region, some of the major activities that have contributed to the interruption of natural hydrologic and geomorphic processes are highlighted. Connections are made between human-induced stressors and subsequent geomorphic and ecological responses. Further, efforts to ameliorate these impacts through physical stream restoration projects and the adoption of environmental flows are discussed. Additional research and adaptive management strategies are needed to improve understanding of the connections between underlying processes and ecosystem conditions to achieve restoration success. (pages 239 - 254)
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    University of Chicago Press
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- Donald W. Sada, Lawrence E. Stevens
DOI: 10.7208/chicago/9780226694504.003.0017
[biodiversity;crenobiontic species;crenoecology;ecostystem rehabilitation;spring types]
Arid-land springs often are small, isolated ecosystems characterized by high levels of productivity, evolutionary and socio-cultural importance, and biodiversity, including rare and endemic crenobiontic species. Springs are numerous, with more than 50,000 reported in the Basin and Range and Colorado Plateau provinces. A dozen geomorphically distinctive spring types have been recognized, each potentially encompassing multiple microhabitats that contribute to their biodiversity. Springs are characterized by highly individualistic geomorphology, flow patterns, water quality, and both crenobiontic and upland assemblage composition, which are influenced by the supporting aquifer and natural and human disturbances. Unfortunately, springs also are among the most threatened and degraded habitats. Due to the absence of surface flow processes, stream-riparian rehabilitation methods often are inappropriate for springs. Spring ecosystem rehabilitation is a rapidly growing science that requires an understanding of the distinctive ecology and restoration challenges presented by springs. Here we present: 1) basic aspects of crenoecology; 2) a description of successional responses to rehabilitation; 3) stewardship guidelines for restoration of springs; 4) the use of information from reference sites; and 5) information gaps and the lessons learned from rehabilitation efforts. (pages 255 - 270)
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- Michael T. Bogan, Carlos Alonso Ballesteros-Córdova, Scott E. K. Bennett, Michael H. Darin, Lloyd T. Findley, Alejandro Varela-Romero
DOI: 10.7208/chicago/9780226694504.003.0018
[amphibians;aquatic invertebrates;conservation;desert springs;fishes;freshwater habitats;Sierra El Aguaje;Sonoran Desert]
In the arid southern Sonoran Desert, the rugged canyons of the Sierra El Aguaje contain numerous freshwater oases. These habitats are supported by small springs which are usually located along geologic faults in volcanic and granitic bedrock. Genetic evidence from freshwater-obligate species (e.g., fish and frogs) suggests these or similar spring-fed habitats have persisted for thousands to millions of years. Though biologists are just beginning to study these habitats, at least 210 species of aquatic invertebrates have been documented, along with several species of fishes, amphibians, and semi-aquatic reptiles. Additionally, euryhaline fishes occasionally colonize freshwater habitats when hurricane-induced floods connect oases with the sea. At least six new, potentially endemic, species of aquatic invertebrates have been found in recent years, but much work remains to be done to fully document the biota of these oases. Groundwater pumping, introductions of nonnative species, and unmanaged human recreation all threaten the biodiversity of these desert oases. We hope this chapter will draw attention to these beautiful habitats and promote conservation of their unique biota (pages 273 - 284)
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- Alejandro Varela-Romero, Carlos Alonso Ballesteros-Córdova, Gorgonio Ruiz-Campos, Sergio Sánchez-González, James E. Brooks
DOI: 10.7208/chicago/9780226694504.003.0019
[catfish;diversity;Mexico;conservation status;Ictalurus;phylogenetics]
México is the center of diversity for the genus Ictalurus of the North American catfish family Ictaluridae, with eight described species and several undescribed forms. Three undescribed forms are allied with I. dugesii on the Mexican Mesa Central. Another one or more undescribed forms, in upper Río Pánuco tributaries, have been confused with I. mexicanus. The remainder are allied with I. pricei or I. lupus, which together form a subgroup of the I. punctatus clade. The number of undescribed species of the latter complex is poorly understood, with one lupus-like form in the Río Conchos (and likely Río Grande in Texas and New Mexico), and three or more pricei-like forms in Pacific Coast systems draining the Sierra Madre Occidental. In the I. furcatus clade, the resurrection of I. meridionalis as a distinct species from the former is presented. All native species of Ictalurus are declining as a result of dams, groundwater withdrawals, pollution, and hybridization with nonnative I. punctatus, and adverse effects of other nonnative fishes. Additional collections, morphological and molecular studies of Ictalurus in México, and formal description of undescribed forms are needed. Formal descriptions will improve opportunities for governmental protection of the native diversity of catfishes in México. (pages 285 - 294)
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    University of Chicago Press
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- David L. Propst, Thomas F. Turner, Jerry A. Monzingo, James E. Brooks, Dustin J. Myers
DOI: 10.7208/chicago/9780226694504.003.0020
[Gila trout;Oncorhynchus gilae;life history;conservation;wildfire;drought;climate change]
Prior to European settlement of Arizona and New Mexico, trout Oncorhynchus sp. occupied higher elevation Gila Drainage streams, but by early 20th Century only a few native trout populations remained, a consequence of habitat degradation and nonnative species. Concerted efforts to conserve Gila trout O. gilae began with passage of the Endangered Species Act. Conservation required securing extant populations, restoring the species to streams reclaimed from nonnative trout, and acquiring life history information. Initial restorations were in small headwaters, but the 1989 Divide Fire, that eliminated the Main Diamond population, exposed the fallacy of that approach. Rather, hydrologically complex drainages sufficiently large that no single natural event could eliminate a population were deemed necessary. Wildfires, drought, compromised populations, and public opposition challenged Gila trout conservation. The 2012 Whitewater-Baldy Fire starkly revealed the vulnerability of Gila trout to increased drought and fire frequency and intensity associated with climate change. Reclassifying Gila trout as ‘threatened’ in 2006 enabled limited angling and improved public support. From five populations in 1970, there are now 17 in almost 125 km of habitat. Ensuring persistence of Gila trout requires securing its remaining genetic diversity, establishing additional populations, and accomplishing this as climate change poses new challenges. (pages 295 - 315)
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    University of Chicago Press
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- Kevin R. Bestgen, Thomas E. Dowling, Brandon Albrecht, Koreen A. Zelasko
DOI: 10.7208/chicago/9780226694504.003.0021
[razorback sucker;Xyrauchen texanus;Colorado River;predation;recruitment;nonnative fish;management;stream flow;habitat alteration;conservation]
Razorback sucker Xyrauchen texanus, a historically widespread and abundant warmwater fish endemic to the Colorado River basin, has declined dramatically. Habitat alteration, dams that block migration routes and alter natural sediment, stream flow, and thermal regimes, channel change, and nonnative fish predation are reasons for decline of razorback sucker. Lack of recruitment was evident more than 50 years ago and all wild fish in basin populations were eventually extirpated, with the possible exception of the small Lake Mead population. Extensive restoration efforts have had mixed outcomes. Various propagation programs have restored reproducing adults in lakes Mohave, Havasu, and Powell in downstream basin reaches, and the San Juan, Colorado, and Green rivers in the upper Colorado River basin. However, nonnative predators reduce survival of stocked fish and recruitment is non-existent except in Lake Mead. Localized recruitment in Lake Mead, and new strategies to enhance juvenile production in isolated lower Colorado River backwaters and connected Green River floodplain wetlands offer examples of recent successes. Further progress toward restoration of large-river fishes including razorback sucker requiresadditional flow, habitat, and nonnative fish management, and continued long-term support for conservation programs. (pages 317 - 334)
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    University of Chicago Press
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- Sean C. Lema, Jennifer M. Gumm, Olin G. Feuerbacher, Michael R. Schwemm
DOI: 10.7208/chicago/9780226694504.003.0022
[refuge;conservation;genetic drift;adaptation;extinction;wetland;desert;phenotype;endangered fishes]
Endemic fishes of groundwater springs and wetlands in the deserts of southwestern North America have declined at an alarming rate over the past century. For some of the most imperiled species, conservation efforts to mitigate threats and protect against extinction include translocating fish to natural or constructed refuge environments. To be successful, however, refuges must support self-sustaining populations while maintaining phenotypic integrity and genetic diversity. And yet, even the best-designed refuges may leave populations vulnerable to local adaptation and genetic drift, which could lead to changes in phenotype or loss of genetic variation. Here, we examine the use of refuges as a conservation strategy to assist the recovery of spring and wetland fishes in the arid American Southwest. Several case studies illustrate the biological and evolutionary consequences of this approach and point to guiding principles for using refuges to help recover endangered fishes. With many desert fishes continuing to face threats from habitat dewatering, nonnative species, and an increasingly arid regional climate, how refuges are designed and implemented will be critical for long-term conservation. (pages 335 - 352)
This chapter is available at:
    University of Chicago Press
    https://academic.oup.com/chica...

- Anthony A. Echelle, Alice F. Echelle
DOI: 10.7208/chicago/9780226694504.003.0023
[conservation;restoration;American West;Oregon chub;Modoc sucker;Borax Lake chub;Gila topminnow;desert pupfish;Pecos gambusia]
Aquatic conservation issues in deserts of the American West center on nonnative species, altered surface-flow dynamics, and overexploitation of inherently scarce water. Resulting levels of degradation are effectively irreversible except locally. Consequently, restoration success is relative to might have been, or would be, without the effort. Presented here are case studies of such successes. One non-desert project is included because it involves the first federally delisted, non-extinct fish (Oregon Chub) and exemplifies restoration of a floodplain species in its natural habitat. Other studies include two primarily floodplain species (Gila topminnow and desert pupfish) transplanted into semi-wild refuges (e.g., stock tanks, ponds, and protected springs), stream-dwelling species (Modoc Sucker and Fossil Creek, Arizona assemblage) positively affected by habitat restoration or restored stream-flow, and assemblages of species endemic or native to springs. The latter include one instance of rescue and transplantation of endemics from a now-dry spring system (Rancho Nuevo springs, Chihuahua) and examples of expanded habitat via marsh (ciénega) restoration (El Pandeño, Chihuahua) or creation of artificial ciénegas (Balmorhea area, Texas). Keys to successes are governmental inter-agency cooperation, conservation-oriented NGOs, and engagement of private landowners. Most successes are short-term without the political and societal will to protect and restore natural systems. (pages 353 - 376)
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    University of Chicago Press
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- Kevin P. Wilson, Mark B. Hausner, Kevin C. Brown
DOI: 10.7208/chicago/9780226694504.003.0024
[Devils Hole pupfish;Supreme Court;aquatic conservation;water rights;endangered species;desert fishes;Ash Meadows]
Devils Hole and the endemic Devils Hole pupfish Cyprinodon diabolis occur within the Ash Meadows section of the Amargosa Desert in southern Nevada. The ecosystem became a flash point in desert fish conservation in the late 1960s, when groundwater development near Devils Hole led to the almost complete dewatering of a shallow, submerged “shelf” that comprises the pupfish’s primary foraging and spawning habitat. The ensuing population crash was halted in 1976 when the Supreme Court affirmed that the National Park Service, which manages the site, had a senior water right to support C. diabolis. Water level, however, has not recovered to predevelopment levels and efforts to protect the pupfish and its ecosystem continue. Three additional management crises—low pupfish population counts that demand an immediate management response—prompted different recovery and conservation approaches by state and federal managing agencies, as well as significant research into the ecosystem. Currently, managing agencies take an adaptive management approach to make decisions with the first goal of “do no harm.” Herein, we describe Devils Hole as a case study, highlighting the importance of scientific research and ecological monitoring in managing endangered species and ecosystems. (pages 379 - 390)
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- Christopher Norment
DOI: 10.7208/chicago/9780226694504.003.0025
[Endangered Species Act;aquatic biodiversity;American Southwest;ideology;post-truth;alternative facts;drought;political action]
The future of southwestern aquatic habitats and their native species is uncertain, due to possible impacts of climate-induced drought, population growth, and over-utilization of scarce water resources, but also to politically and ideologically motivated attacks on the Endangered Species Act, and federal land management and regulatory authority. However, a potentially more profound danger is the development of a “post-truth” culture that accepts the notion of “alternative facts” and distrusts science. Such attitudes will make it difficult to develop effective approaches to counter likely, future droughts in the American Southwest, and consequent threats to regional aquatic biodiversity. Crafting a sustainable future for the Southwest and its native species and ecosystems will require a robust scientific understanding of the region’s natural variability and system complexity, advances in public policy and management, and evaluating the role that wealth plays in affecting decisions about allocating and managing natural resources. However, it also will require effective political action, and that a critical mass of people transcend blinding ideology, convention, and human short-sightedness. Finally, progress demands that we imagine the realms of our possible futures, and consider the historical context of past, present, and future efforts to protect regional aquatic biodiversity in the American Southwest. (pages 391 - 406)
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    University of Chicago Press
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- Christopher W. Hoagstrom, Kevin R. Bestgen, David L. Propst, Jack E. Williams
DOI: 10.7208/chicago/9780226694504.003.0026
[desert fishes;ecological ratchet;megadrought;wicked problems;extinction]
Lineages of desert fishes that have persevered millions of years, through droughts exceeding any in the historical record, now collectively spiral toward extinction in the industrialized desert signaling the loss of functioning aquatic ecosystems. A century of large-scale water-resource development for agricultural and urban expansion has diminished these ecosystems to a point that exceeds prehistoric megadroughts, although the accompanying climate is relatively wet. Anthropogenic habitat degradation and introductions of nonnative species exacerbate ecological depreciation. Persistent impacts create an ecological ratchet that now elevates extinction risks for remnant populations. Full restoration of natural habitats may be impossible today, but preservation and rehabilitation of remnant ecosystems and their functions are critical. Collaborative approaches to reverse ratchet-like impacts could reduce extinction risks but need more public support and wider application. This is a wicked problem because resource managers face many limitations and require cooperation among numerous private and governmental organizations representing diverse values and priorities. Greater fusion of science, environmental ethics, and ecological economics could unveil common ground among stakeholders, which will be critical to forestall looming threats. (pages 407 - 418)
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