2019 Abstracts & Presentations

John L. Peterson, U.S. Army Corps of Engineers

Like many areas in the arid southwest, the middle Rio Grande Valley has seen drought for approximately a decade. This has impacted the bosque’s riparian ecosystems and the environmentally sensitive species that live there, agriculture, and water delivery to compact partners downstream. Fortunately the winter of 2018-2019 saw extremely large, above average snow packs in the upper Rio Grande watershed resulting in much higher than average runoff levels through this reach. This year’s runoff provided an opportunity to geospatially document the ascending high flow hydrograph of the middle Rio Grande from Cochiti Lake through Albuquerque, NM, downstream to Elephant Butte Lake, by way of the collection of Pleiades 4-band satellite and 4-band digital aerial imagery. Hopefully, these data sets will lend themselves to document the effects of high flow runoff on levee integrity, inundation and overbanking extents within the bosque, and impacts on bird and fish habitats. An overview of these data sets and their potential uses will be presented.

Deanna Wilson, U.S. Army Corps of Engineers

Like many areas in the arid southwest, the middle Rio Grande Valley, from Cochiti Lake through Albuquerque, NM, downstream to Elephant Butte Lake, has seen drought for approximately a decade. This has impacted environmentally sensitive species, agriculture, and water delivery to compact partners downstream. Fortunately the winter of 2018-2019 saw extremely large above average snow packs in the upper Rio Grande watershed resulting in much higher than average runoff levels through this reach.

This year’s high flow runoff provided an opportunity, led by the Corps of Engineers, to enlist multi-agency collaborative partner participation toward the objective of monitoring and documenting the effects of high flow runoff on levee integrity, inundation and overbanking extents, and fish spawning, habitat. To accomplishment this, ESRI’s Collector mobile device application was implemented as the first coordinated multi-agency undertaking of its kind for documenting this event. Using ArcGIS On-line Mapping facilitated near real time monitoring that was shared by all participating agencies. This application and the results of the monitoring exercise will be presented.

David J. Van Horn, University of New Mexico, Department of Biology

Beginning in 2006 and continuing through October 2019, the Army Corps of Engineers and the University of New Mexico Department of Biology collaborated to install and maintain a water quality monitoring network in the Middle Rio Grande (MRG). This network consisted of seven sensors spanning approximately 200 river kilometers, from an upstream site near Embudo NM, to a downstream site at the Isleta Diversion Dam, NM. The instruments recorded near continuous (15-minute interval) data for five water quality parameters, with over 10 million datapoints collected during the 13 years of this project. The spatial and temporal breadth of this data has facilitated the investigation of both trends in water quality and basic ecosystem processes, and the impacts of episodic disturbance events. The trends and processes explored include; 1) an analysis of the spatial and temporal variability of whole stream metabolism values over two years at three sites along an ~90 kilometer reach of the MRG, 2) the impact of snowmelt and monsoon pulse flow disturbances on gross primary production at a single site on the MRG over a semi-consecutive ten-year period, and 3) a three-year comparison of the water quality in drain outfalls that could serve as potential refugia for MRG fish communities to conditions in the main-stem of the river. Disturbance impacts that have been documented include; 1) the effects of urban and non-urban storm inputs on water quality during a single monsoon season, and 2) the effects of a catastrophic wildfire and subsequent flood on the water quality and fish communities of the MRG. These examples highlight the importance of collecting long-term datasets to assess river function and determine the impacts of unpredictable episodic disturbances.

Other Authors:
Justin K. Reale, U.S. Army Corps of Engineers
Cliff N. Dahm, Department of Biology, University of New Mexico
Thomas P. Archdeacon, U.S. Fish & Wildlife Service
Ricardo González-Pinzón, Department of Civil, Construction & Environmental Engineering, University of New Mexico
Peter J. Regier, Department of Civil, Construction & Environmental Engineering, University of New Mexico
Matthew Segura, Department of Biology, University of New Mexico
Betsy M. Summers, Department of Civil, Construction & Environmental Engineering, University of New Mexico

Peter Regier, University of New Mexico, Department of Civil, Construction & Environmental Engineering

Stormwater runoff represents an important component of Rio Grande discharge and alters water quality, with potentially deleterious consequences affecting downstream ecology and influencing management decisions. However, the water quality characteristics of runoff sourced from urban versus non-urban catchments differ through space and time, and are not well constrained for the Middle Rio Grande. We used a network of high-frequency in-situ water quality sensors located between Cochiti reservoir and southern Albuquerque to constrain stormwater origins and track rapid changes in physical, chemical, and biological components of water quality. Specific conductivity (SpCond) patterns were a reliable indicator of source, distinguishing between runoff events originating primarily in urban (SpCond sags) or non-urban (SpCond spikes) catchments. Urban events were characterized by increased fluorescent dissolved organic matter (fDOM), low dissolved oxygen (including short-lived hypoxia), and varied pH, temperature and turbidity responses. In contrast, non-urban events showed large turbidity spikes, smaller dissolved oxygen sags, and lower pH. Principal component analysis distinguished urban and non-urban events primarily by SpCond, fDOM, and turbidity, and suggested biogeochemistry drives urban water quality, while physical processes drive non-urban water quality. Based on transfer function modeling and load estimates, urban events are associated with higher oxygen demand and larger dissolved organic carbon loads, while non-urban events show minimal oxygen demand, but significantly higher total suspended sediments and total dissolved solids loads, relative to baseline. Based on these findings, urban storms more strongly affect biological conditions in the Middle Rio Grande, while non-urban storms predominantly affect physical aspects of water quality.

Other Authors:
Ricardo González-Pinzón, Department of Civil, Construction & Environmental Engineering, University of New Mexico
Justin K. Reale, U.S. Army Corps of Engineers
David J. Van Horn, Department of Biology, University of New Mexico
Justin Nichols, Department of Civil, Construction & Environmental Engineering, University of New Mexico
Aashish Khandewal, Department of Civil, Construction & Environmental Engineering, University of New Mexico

Justin K. Reale, U.S. Army Corps of Engineers

Few studies have evaluated the effects of wildfire on downstream water quality and fish assemblages in large arid-land rivers. Using data from a high-frequency water quality monitoring network in the Middle Rio Grande (MRG) we analyzed dissolved oxygen (DO) at five sites following the Las Conchas fire (2011). In the flood events immediately following the fire, we documented DO sags to 0.0 mg L^-1 that propagated at least 50 km downstream. During the first three years post-fire, we observed numerous DO sags < 3 mg L^-1. Episodic sags < 5 mg L^-1 persisted through 2018. We also leveraged long-term fish community surveys in the MRG to assess the response of a cypriniform-dominated assemblage at two sites most proximal to the wildfire. Despite the poor water quality conditions, the fish assemblage at both sites was resistant with the exception of Longnose Dace (Rhinichthys cataractae) and Fathead Minnow (Pimephales promelas) at the upstream site. Following a major flood in September 2013, total fish density, richness, diversity, and density of Longnose Dace, Fathead Minnow, and Flathead Chub (Platygobio gracilis) were negatively impacted at the upstream site. These native species and the greater fish assemblage were unaffected by the flood at the downstream site. We attributed the variability in the fish community response to differences in spatial factors related to the burn scar, site-specific physical characteristics, and species-specific traits. As wildfire timing, frequency, and severity have increased across the western US over the last several decades, it is critical for water and resource managers to be aware of the potential impacts to water quality and biota in arid-land catchments that are susceptible to wildfire.

Other Authors:
David J. Van Horn, Department of Biology, University of New Mexico
Clifford N. Dahm, Department of Biology, University of New Mexico
Thomas P. Archdeacon, U.S. Fish and Wildlife Service
Eric J. Gonzales, U.S. Bureau of Reclamation
Robert K. Dudley, American Southwest Ichthyological Researchers & Division of Fishes, Museum of Southwestern Biology, University of New Mexico
Thomas F. Turner, Division of Fishes, Museum of Southwestern Biology, University of New Mexico

Betsy M. Summers, University of New Mexico, Department of Civil, Construction & Environmental Engineering

Globally, aridlands comprise one third of the terrestrial land mass, however, limited research has been conducted on the streams and rivers that drain these regions. This is particularly true for measurements of whole stream metabolism (gross primary production – GPP, ecosystem respiration – ER), a knowledge of which is fundamental for understanding and managing these systems. Aridland rivers are characterized by flashy hydrographs, high turbidity levels, variable flow, and overallocated water resources, all of which create temporally and spatially complex ecosystems with likely impacts to metabolism. Two years of whole-stream metabolism estimates were generated at three sites spanning 93 river km along the Middle Rio Grande to assess the variability in GPP and ER across and within sites at daily and seasonal timescales. This river varies longitudinally in discharge, geomorphology, and anthropogenic impacts. Differences in substrate type and geomorphology across sites resulted in spatially and temporally variable patterns in whole stream metabolism. At the upstream site, GPP peaked (daily – 2.2 gO2 m-2 d-1, monthly average – 1.6 gO2 m-2 d-1) in-phase with light availability and turbidity during summer. At the middle site, GPP peaked either in the fall, or at multiple points through the summer/fall (daily and monthly peak values of 2.9 gO2 m-2 d-1 and 1.7 gO2 m-2 d-1, respectively), depending on discharge. At the most downstream site, GPP predictably peaked during fall (daily and monthly peak values of 2.2 gO2 m-2 d-1 and 1.2 gO2 m-2 d-1, respectively) when both discharge and turbidity were low. Autotrophy was common at the middle site, which has coarse cobble substrate, while heterotrophy was associated with the fine-grained sand and silt substrates found at the upper and lower sites. In this aridland river, a combination of discharge, turbidity, geomorphology, and substrate type are key determinants of daily GPP and trophic conditions.

Other Authors:
David J. Van Horn, Department of Biology, University of New Mexico
Justin K. Reale, U.S. Army Corps of Engineers
Ricardo González-Pinzón, Department of Civil, Construction & Environmental Engineering, University of New Mexico
Alison P. Appling, U.S. Geological Survey
Rebecca J. Bixby, Department of Biology, University of New Mexico
Mark C. Stone, Department of Civil, Construction & Environmental Engineering, University of New Mexico

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Ariane O. Pinson, U.S. Army Corps of Engineers

Riverine sediment in the Middle Rio Grande is essential for the creation of habitat for native species (willows, cottonwoods) and the creation of fish habitat. Sediment in riverine systems originates from both terrestrial (from the combination of soil erosion and overland transport) and in-channel sources, and is responsive to changes in land use (including infrastructure development), land cover, and climate. This paper explores how projected changes in climate and land use may affect terrestrial sediment supply in the Middle Rio Grande below Cochiti Reservoir over the 21st Century. Historic watershed soil loss rates are modeled using the Revised Universal Soil Loss Equation (RUSLE) forced with observed precipitation rates (Livneh et al. 2013) and historic land use/land cover (LULC) data from the USGS LandCarbon study (Sohl et al. 2016). The RUSLE model is then forced with LOCA modeled precipitation data (Bureau of Reclamation 2013) and LandCarbon LULC data for two 21st C epochs (Sohl et al. 2014) in order to assess changes in future terrestrial sediment supply rates within the basin.

Kyle Stark, New Mexico Tech & U.S. Army Corps of Engineers

Lateral input of sediment to the Rio Grande from ephemeral channels is poorly quantified. Measuring sediment discharge is difficult in a desert setting: these channels flow only a few times a year, often for just a few hours at a time. Even so, they are the only source of sediment for much of the Rio Grande south of Albuquerque, where no perennial river feeds the Rio until Texas.

The Arroyo de los Piños sediment monitoring station was built to address this knowledge gap. The station represents one of only a few locations worldwide where continuous sediment flux measurements are collected. Our initial findings indicate sediment is being transported at globally high rates: bedload fluxes of up to 16 kg/s-m were recorded in 2018 (the first year of operation). More intriguing is the grain size distribution of the transported sediment. At low flows, sand-sized particles make up the majority of the sediment in transport. As water discharge, larger, gravel-sized particles become entrained and begin making their way downstream. The grain size distribution of sediment input is crucial for understanding the habitat availability for silvery minnow populations. Large floods along arroyos can produce low-velocity zones of debris and gravel within the Rio Grande (which are ideal silvery minnow habitat). These areas persist until snow-driven spring runoff events are large enough to efficiently move the larger gravel and cobbles deposited by arroyos. Through better understanding sediment delivery to the Rio Grande from arroyos, we aim to add additional understanding of how silvery minnow habitat is formed and changed spatially and temporally.

Other Authors:
Daniel Cadol, New Mexico Tech
Madeline Richards, New Mexico Tech
Sharllyn Pimentel, New Mexico Tech

Lucy Moore, Lucy Moore Associates

Rebecca Bixby, University of New Mexico

The Rio Grande is an aridland river with high turbidity and shifting substrates, which confines algal production to a shallow, temporary edge along the river. Biological communities in aridland rivers, including grazing invertebrates and fish, are often reliant on this “bathtub ring” of autochthonous algal production as a critical food resource. Our research program focuses on algal community structure and function in aridland rivers and investigates the role of the key drivers (e.g., turbidity, flow, seasonality) that shape these communities. Throughout the Middle Rio Grande, algal communities are influenced by substrate type, nutrient inputs, turbidity concentrations, and discharge. Upstream, the community is dominated by taxa that tolerate/prefer low levels of nutrients and lower levels of turbidity. By comparison, downstream sites are dominated by silt/sand loving species and taxa tolerant of moderate nitrate concentrations. Further investigation has mapped the spatial extent of the algal bathtub ring along the river edge. Detailed sampling has shown that the bathtub ring is generally constrained by velocity > 0.2 ms^-1 and water depths < 12 cm during most seasons. Finally, current research seeks to understand the relationship between hydraulics and biological parameters in the bathtub ring. Local changes in flow (e.g. velocity, turbulence) and large-scale hydraulic events (e.g. discharge) appear to be important variables driving differences in the biological community among locations. Overall, understanding algal dynamics in the Middle Rio Grande is key to documenting the energy sources for aridland river food webs which can have limited primary production in the water column. Additionally, insight into diversity and drivers of algal assemblages is crucial to understanding stochasticity and seasonality in these dynamic aridland ecosystems.

Other Author:
Ayesha Burdette, River Bend Ecology

Presentation unavailable. Contact dlee@west-inc.com for more information.

Jonathan Dombrosky, University of New Mexico, Department of Anthropology

Information on how ecosystems, communities, and populations functioned in the historic or prehistoric past can provide managers important context to set clear goals and assess progress towards those goals. Researchers concerned with fishes of the Middle Rio Grande (MRG) typically use longitudinal records within the historic period (before or during the mid-20th century) to elucidate baseline conditions prior to extensive anthropogenic impacts related to water impoundment and/or diversion. Unfortunately, prehistoric conditions are rarely considered and natural variation in how the MRG ecosystem functioned may be underestimated. Here, we seek to quantify the different sources of primary production that prehistoric MRG fish communities relied on. To do so, we analyze the carbon isotope composition (δ13C) of bulk bone collagen and its constituent essential amino acids from fish remains recovered from two MRG archaeological sites occupied between AD 1300 and 1600: Chamisal Pueblo and Kuaua Pueblo. Our results indicate that detritivorous suckers (family Catostomidae) relied on a mix of autochthonous (algae) and allochthonous terrestrial resources derived from C3 plants (e.g., cottonwoods and willow). Carnivorous trout (Oncorhynchus spp.) and omnivorous catfish (family Ictaluridae) relied on a mix of algae and terrestrial C3 and C4 (grass) plant production. Taxa extirpated from the MRG, like gar (Lepisosteus spp.) and shovelnose sturgeon (Scaphirhynchus platorynchus), heavily relied on allochthonous C4 plant production. We argue that detritus derived from allochthonous C3 and C4 plants was an important source of energy for the prehistoric MRG aquatic food web and helped support a more complex and diverse MRG fish community. We plan to analyze additional extirpated taxa, like the blue sucker (Cycleptus elongatus) and more gar, from the upper and lower Rio Grande in New Mexico in the future. Overall, archaeological material highlights the crucial role that floodplain connectivity had in maintaining MRG biodiversity in the past.

Other Authors:
Emma A. Elliott Smith, Department of Biology, University of New Mexico
Alexi Besser, Department of Biology, University of New Mexico
Seth D. Newsome, Department of Biology, University of New Mexico

Presentation unavailable. Contact dlee@west-inc.com for more information.

Megan Osborne, University of New Mexico

The endangered Rio Grande silvery minnow (Hybognathus amarus) persists in New Mexico as a remnant population in a highly fragmented and regulated arid-land river system. Since 1999, the population (n = 6,014) has been subjected to annually genetic monitoring using nine microsatellite loci and from a mitochondrial DNA gene. This represents one of the longest genetic monitoring time series for a non-salmonid freshwater fish. Genetic monitoring tracks contemporary changes to empirical measurements of genetic diversity including allelic richness, heterozygosity, and genetic effective population size. The development of high-throughput single nucleotide polymorphism (SNP) genotyping, statistical tools and computational software now allows genetic monitoring programs to genotype 100-1000s of genetic loci more representative of the wider genome than previous genetic markers. Results from the 20-year time series (based in microsatellites and mtDNA) indicates that genetic diversity has been maintained in Rio Grande silvery minnow despite repeated population crashes; likely a result of the captive breeding/rearing and augmentation programs that commenced in 2002. Genetic monitoring data also shows that population declines are generally accompanied by the reduction in genetic effective population size. Here we present preliminary SNP data for 378 archived Rio Grande silvery minnow samples collected from 1999 to 2018 representing the current occupied river reaches. We compare results from SNP loci to microsatellite and mtDNA data to provide insights into the genetic status of Rio Grande silvery minnow. The sampling strategy utilized in this study allows examination of the impacts of changes in abundance, management actions and environmental conditions on genetic diversity metrics.

Presentation unavailable. Contact dlee@west-inc.com for more information.

Michael D. Porter, U.S. Army Corps of Engineers

Rio Grande silvery minnow (Hybognathus amarus, silvery minnow) reproduction and early life history have been the subject of multiple studies over the last twenty years. Several mechanisms for egg and larval transport in the Rio Grande and retention in mesohabitats have been described by various field studies. The extent these mechanisms contribute to reproduction, recruitment, and population dynamics provide useful insights into silvery minnow ecology for adaptive management.

Field and laboratory studies have identified possible transport mechanisms for eggs and larvae in the main channel and to floodplain nursery habitat. Water-hardened eggs are semi-buoyant (specific gravity = 1.00281± 0.00008), sink slowly, and saltate in water currents. These hydrophysical properties increase their chances of retention and entrainment along irregular shoreline features and floodplains, and reduces long-distance transport. Illustrating the egg semi- buoyancy interactions with flowing water provide insights into understanding nursery habitat requirements and constraints to survival and recruitment. This presentation will highlight key results from twenty years of studies to integrate hydrology and physics with transport processes to illustrate spatial patterns of distribution of nursery habitat and silvery minnow recruitment. Understanding the transport of Silvery Minnow life stages to nursery habitat is an essential foundation for designing appropriate habitat restoration and environmental flow strategies.

Douglas Tave, N.M. Interstate Stream Commission, Los Lunas Silvery Minnow Refugium

Schooling is a behavior regularly observed in Rio Grande silvery minnow cultured in the naturalized conservation mesocosm (refugium). Schooling starts when the fish can swim directionally. Fish school by size. Schools of about 4,000 (22,200/m²) have been observed in ten-mm fry. School size of adults has been as large as 700-740 (117/m²). Schools are not static but traverse the stream and enter ponds. Often, a school will break up into smaller schools and regroup later in the day. Schooling behavior has several implications for management. First, schooling produces what is called a contiguous spatial distribution, which suggests that a block design sampling program is needed to accurately assess the population of the Middle Rio Grande. Additionally, randomly placed fixed sampling sites are likely to miss fish concentrations and product underestimations of the population due to school movement. Second, feeding fish in the hatchery could have a negative effect on survival of wild fish following augmentation. Feeding fish during culture increases aggressive behavior. Schooling is a delicate balance between attracting and repelling behavior; feeding will disrupt this balance and, if fed hatchery fish school with wild fish, it will be a less cohesive and more dispersed school. A major benefit of schooling is predator avoidance, so if a school is more dispersed, fish in that school will be more vulnerable to predation. The third implication is for spawning. A spawning study in the refugium revealed that small schools of adults moved with the water as off-channel floodplains inundated. This species likely spawns when the fish are in schools. Because schools appear to move onto floodplains on the increasing limb of the hydrograph, it is important to have hydraulic connection to floodplains along as much of the river as possible to allow schools to move onto the floodplains to spawn.

Other Authors:
Louie A. Toya, Los Lunas Silvery Minnow Refugium, N.M. Interstate Stream Commission
Alison M. Hutson, Los Lunas Silvery Minnow Refugium, N.M. Interstate Stream Commission

Benjamin J. Stout, Utah State University, Department of Watershed Sciences, and Ecology Center

Humans and fishes compete with one another for water, the most precious resource in the West, and consequently we have dramatically altered the hydrologic regime of rivers globally. Our ever increasing demand for water combined with more frequent drought has led to the drying and fragmentation of rivers and habitat for fishes. In extremely dynamic systems, fishes’ ability to find refugia and recolonize the river after the river returns to wetted conditions is incredibly important to ensure species persistence. The overall goal of this study was to determine the capacity and extent of highly imperiled and federally-endangered Rio Grande Silvery Minnow (Hybognathus amarus; RGSM) movement in a large, fragmented river. For the pilot of many more study events, working with partners, we released two different age classes of PIT tagged RGSM (a total of 1701) in the San Acacia reach of the Rio Grande River, and used three different types of PIT tag antennas to detect individuals and track their movement. We detected over 57% of the fish released. Only one quarter of movement was upstream. The largest upstream movements (~13 km) exhibited no differences between age classes and were smaller than the largest downstream movements (~29 km). However, older fish moved larger distances downstream. Cumulative distances moved were highly variable with a median of 3.8 km to a maximum of 43.9 km. The ability to disperse allows fish to react to changes in its environment and find suitable complementary habitat types. Based on preliminary information, hatchery-raised Rio Grande Silvery Minnow display a capacity for large movements, allowing the recolonization of habitats when they become available. This was a pilot study; based on preliminary results and extremely high detection rates, we will now continue the study across seasons, with the next release of 10,000 tagged individuals distributed over a larger geographical extent.

Other Authors:
Phaedra Budy, U.S. Geological Survey, Utah Cooperative Fish and Wildlife Research Unit, Department of Watershed Sciences, and Ecology Center, Utah State University
Peter Mackinnon, Department of Watershed Sciences, Utah State University
Mark McKinstry, U.S. Bureau of Reclamation

Robert Dudley, American Southwest Ichthyological Researchers & University of New Mexico, Museum of Southwestern Biology, Division of Fishes

The objectives of this study are to characterize and assess the timing, duration, and magnitude of spawning for Rio Grande Silvery Minnow Hybognathus amarus in the Middle Rio Grande. Overall, the estimated egg passage rates (E(x); eggs / s) at Sevilleta and San Marcial were consistently higher than at Albuquerque, but the seasonal timing/duration (ca. late April to early June) and interannual passage-rate trends (2006–2019) were similar across sites. Logistic regression modeling, using San Marcial data (2003–2019), revealed that the daily probability of collecting eggs (i.e., probability of occurrence) during a 100% daily increase in flow was 0.80, whereas the probability was 0.97 during a 200% increase in flow. In contrast, the probability of occurrence declined with increasing water temperatures, from 0.51 (14°C) to 0.26 (26°C). Egg passage rates, estimated using San Marcial data (2003–2019), were highest in 2011 (6.05 x 10¹) and lowest in 2004 (1.36 x 10^-3). Based on the resulting top ecological models, we found that egg occurrence probabilities were higher during years with reduced and truncated spring flows, and that egg passage rates were lower during years with elevated and extended spring flows. It is likely that the proportion of individuals retained and successfully recruited upstream is related to the availability of nursery habitats (i.e., shallow, warm, productive areas), which are most common during years with high spring flows. As the successful growth and survival of individuals, from the egg through the early larval phases, requires about one month, the long-term persistence of these habitats is essential during this initial developmental period. The future conservation status and recovery of Rio Grande Silvery Minnow appears strongly dependent on reliably ensuring appropriate seasonal flow and habitat conditions that will promote the successful spawning and early recruitment of this imperiled species.

Other Authors:
Adam L. Barkalow, American Southwest Ichthyological Researchers
Tessia O. Robbins, American Southwest Ichthyological Researchers
Steven P. Platania, American Southwest Ichthyological Researchers & Division of Fishes, Museum of Southwestern Biology, University of New Mexico
Gary C. White, Department of Fish, Wildlife, and Conservation Biology, Colorado State University

Thomas P. Archdeacon, U.S. Fish and Wildlife Service

Many once-perennial rivers have become intermittent. Drying is a major influence on aquatic organisms and can result in catastrophic mortality if refugia are not available. Understanding how fishes use refugia can provide insight for species persistence and help stakeholders manage limited resources.

We examined spatial and temporal patterns of Rio Grande silvery minnow (Hybognathus amarus) abundance in isolated pools over a decade of drying, and describe pool characteristics and persistence of isolated pools over time. We used generalized mixed-effects linear models to relate counts of Rio Grande silvery minnow to pool depth, rate of drying, and distance to an upstream barrier. We examined pool persistence, factors that influenced pool persistence, and the relative frequency of Rio Grande silvery minnow that occurred in pools that persisted or dried completely before flows returned.

We provide multiple lines of evidence that pools are not refugia and that Rio Grande silvery minnow do not move upstream in great numbers to escape drying. Nearly all pools dry before flows return, while 99% of Rio Grande silvery minnow were stranded in pools that dried completely. Adults were collected in greater numbers closer to an upstream barrier, while age-0 were collected in greater numbers downstream. Rate of drying had little effect on the numbers of Rio Grande silvery minnow trapped in isolated pools.

We conclude channel intermittency causes catastrophic mortality of fishes through complete desiccation of pools, and poses a novel environment for these fishes. For Rio Grande silvery minnow, lacking other connected, wild populations to compensate and recolonize areas of drying jeopardizes their persistence in the Middle Rio Grande without other intervening management actions. Historically, persistence in the face of drying likely was accomplished by the species being widespread and abundant in a barrier-free river.

Other Author:
Justin K. Reale, U.S. Army Corps of Engineers

Stephen A. Zipper, SWCA Environmental Consultants

Larval Rio Grande silvery minnow Hybognathus amarus (RGSM) were collected in May and June 2017 from the Middle Rio Grande, and 66 specimens were selected to represent varying standard lengths, developmental phases, and collection dates. Lapilli and sagittae were removed from specimens and daily ages were determined using light microscopy. The number of increments on each lapillus or sagitta was interpreted as daily age (days post-hatch) and used to back-calculate hatch date from date of capture. Results from this study indicate that standard length and water temperature at the capture site were significant predictors of daily age. However, there was no difference in growth trajectories among reaches. This study showed that lapillar otoliths of wild RGSM larvae can be used to estimate daily age. Back-calculations of hatch date indicate that RGSM spawned as early as April 18, 2017. This information is important in providing data for growth models to estimate hatch dates and to inform water management that enhances nursery habitat.

Presentation unavailable. Contact dlee@west-inc.com for more information.

Yasmeen Najmi, Middle Rio Grande Conservancy District

Richard A. Valdez, SWCA Environmental Consultants

The Middle Rio Grande (MRG) was historically a wide, shallow, braided channel that migrated laterally with expansive and variable spring flooding. The contemporary river has been diked and narrowed for flood control and regulated by water operations, reducing the frequency and magnitude of overbank flooding. These geomorphic and hydrological changes have disrupted the reproductive phenology of broadcast spawning fishes, including the endangered Rio Grande silvery minnow (Hybognathus amarus, silvery minnow). A positive relationship between spring river discharge and October catch-per-unit-effort (CPUE) suggests that the silvery minnow is an evolved floodplain-dependent species, but the mechanisms behind this relationship are poorly understood. Natural and restored floodplains of the MRG were sampled April−June 2016−2019, with a focus on spawning, egg incubation, and larval development of silvery minnow. A large proportion of adult silvery minnow in floodplains were gravid or spent females and ripe males, indicating that substantial spawning and egg incubation is taking place within inundated floodplains. Silvery minnow were the most abundant larvae of ten fish species found in floodplains, and their residence time in this nursery habitat appears to be related to developmental phase, where the larvae become increasingly mobile with fin and fin-ray development in the postflexion mesolarval and metalarval phases at 14−22 days post-hatch. These studies show that: (1) timing of floodplain inundation affects the availability of nursery habitat for the newly-hatched larvae and the synchrony of food production; (2) magnitude of inundation affects the amount of floodplain habitat available; and (3) duration of inundation is necessary for larval development. The silvery minnow appears reliant on floodplain habitat for spawning, egg incubation, and larval nursery, and coordinated water management, as hydrological conditions allow, can enhance floodplain inundation and promote reproductive success and recruitment of silvery minnow.

Jake Mortensen, American Southwest Ichthyological Researchers

The Middle Rio Grande has experienced considerable geomorphic change resulting from river engineering, reduced magnitude and frequency of peak flows, increased duration and frequency of low flows, establishment of invasive riparian vegetation, and complex sediment dynamics. Hydrologic and geomorphic impacts have contributed to the decline of the remnant wild population of Rio Grande Silvery Minnow Hybognathus amarus, motivating research and conservation of this federally-listed endangered species. There is a need to link our knowledge of the morpho-dynamics (i.e., interaction of hydrologic and geomorphic processes) of the Middle Rio Grande with the habitat conditions required by the Rio Grande Silvery Minnow to improve our holistic understanding of this complex and dynamic ecosystem. The goal of this study is to perform spatiotemporal analyses of habitat conditions on the Middle Rio Grande using long-term, systematically collected datasets (e.g., stream gaging, channel surveys, ichthyofaunal monitoring). Our objectives are to synthesize data and knowledge of the Rio Grande Silvery Minnow and Middle Rio Grande across diverse river sciences (e.g., biology, ecology, hydrology, geomorphology, and engineering), delineate and assess linkages between morpho-dynamics and habitat conditions for this imperiled species, and provide recommendations for data collection efforts needed to better characterize and understand linkages, as well as river management practices that have potential to improve habitat conditions. Analyses incorporate interdisciplinary methods (e.g., habitat criteria, life history models, hydraulic models, channel evolution models) to address species-specific habitat needs such as floodplain connectivity, instream habitat complexity, and geomorphic suitability for habitat restoration. This work is part of an ongoing, multi-year, collaborative research program; this presentation will provide current progress, including data synthesis efforts, interdisciplinary approaches and methods, initial hypotheses, and preliminary results.

Other Authors:
Robert K. Dudley, American Southwest Ichthyological Researchers & Museum of Southwestern Biology, University of New Mexico
Steven P. Platania, American Southwest Ichthyological Researchers & Museum of Southwestern Biology, University of New Mexico
Thomas F. Turner, Department of Biology & Museum of Southwestern Biology, University of New Mexico
Pierre Y. Julien, Department of Civil and Environmental Engineering, Colorado State University
Sydney Doidge, Department of Civil and Environmental Engineering, Colorado State University
Ari J. Posner, U.S. Bureau of Reclamation
Drew C. Baird, U.S. Bureau of Reclamation

Aubrey E. Harris, U.S. Army Corps of Engineers

Projects with the goal of creating habitat for the Rio Grande Silvery Minnow (minnow) have been underway on the Middle Rio Grande since the 1990’s. Though localized efforts to quantify habitat have been made, a standard method for quantifying the amount and quality of habitat constructed and persisting in the dynamic river system has yet to be developed. Through a case study analysis, this presentation proposes the use of the Army Corps of Engineers Hydraulic Engineering Center’s (HEC) modules to visualize, quantify, and track changes in minnow habitat on the Middle Rio Grande. To utilize engineering models, a hypothesis of ideal habitat conditions for the minnow were characterized into hydraulic parameters. Shallow depth, slower velocities and sufficient duration of inundation are three habitat characteristics believed to be crucial for the survival of the early-life stage minnows rearing on the floodplain. Version 5.0 of the Hydraulic Engineering Center’s River Analysis System (HEC-RAS) features the ability to perform two-dimensional hydrodynamic routing producing detailed 2D channel and floodplain analysis which enables depth and velocity characteristics to be quantified. Coupling HEC-RAS 5.0 with the HEC-Ecological Function Model (HEC-EFM) version 4.0, the duration of minnow habitat under various flow regimes can also be computed. Using these tools, the amount, quality and duration of important habitat characteristics can be quantified and repeated using monitoring data to track changes over time, providing managers with the information they need to understand how a site is performing and make informed management decisions.

Other Authors:
Ashlee Rudolph, U.S. Bureau of Reclamation
Jen Bachus, U.S. Bureau of Reclamation
Eric Gonzales, U.S. Bureau of Reclamation

Trevor Fetz, Hawks Aloft

Beginning in December 2003, Hawks Aloft, Inc. conducted avian transect surveys in the Middle Rio Grande Bosque between Rio Rancho and La Joya WMA, New Mexico. This project includes 81 transects that are surveyed three times monthly during winter (December-February) and summer (June-August). Survey protocol and community and structure (C/S) type designations are based on those used in the early 1980’s Middle Rio Grande Biological Survey (Hink and Ohmart 1984). Avian use during both summer and winter was highest in densely vegetated habitats adjacent to water or incorporating a substantial component of New Mexico olive and/or Russian olive. Avian use was lowest in habitats subjected to substantial thinning or dominated by salt-cedar. Cumulative (2004-2018) summer avian density was highest in marsh habitat (1343 birds/100 acres) and lowest in open, thinned habitat (170 birds/100 acres). Cumulative winter density was highest in dense, mature Russian olive-dominated habitat (1396 birds/100 acres) and lowest in mature cottonwood habitat with substantial understory thinning (94 birds/100 acres). The U.S. Army Corps of Engineers conducted restoration work on 21 transects we survey. Restoration at most of these sites included both the creation swale and bank terrace habitat and upland replanting. Most sites were restored in 2011 and long-term drought limited vegetation growth and subsequent bird use through 2015. But, improved conditions in 2016 and 2017 resulted in substantial growth and increased bird use, especially in lowland portions of the restoration areas. Our data illustrate the importance to the bosque avian community of dense habitat comprised of native vegetation (with New Mexico olive and cottonwood being the most important) or incorporating a substantial Russian olive component. Russian olive is heavily exploited by bosque birds and mature, berry producing individuals should be retained. Russian olive importance may increase as the bosque adapts to drier conditions related to climate change.

Other Author:
Gail Garber, Hawks Aloft

Stephen Ryan, U.S. Army Corps of Engineers

The U.S. Army Corps of Engineers, Albuquerque District’s Environmental Resources Group conducted a study of nesting raptors in the Middle Rio Grande Bosque during the 2019 breeding season from Corrales south through Albuquerque to the I-25 Bridge. This is a continuation of an ongoing study beginning in 2004, with minor changes in the reaches monitored. Primary objectives of the study were: 1. maintain a database of active raptor nests; 2. Identify species of raptors nesting in the Bosque; and 3. Determine the density and productivity of nests. As apex species, raptors provide an efficient way to monitor the health of the ecosystem for wildlife as their nests are relatively easy to locate and monitor. Raptors prey on a variety of taxa, including small mammals and birds, therefore determining raptor abundance and nest productivity is a useful indicator of wildlife population trends in general. Monitoring breeding raptors is important to ensure efforts to maintain the Bosque are improving conditions for all wildlife.

During the 2019 season we monitored 47 active nests representing 7 species of raptors: Cooper’s Hawk (Accipiter cooperii), Great Horned Owl (Bubo virginianus), Swainson’s Hawk (Buteo swainsoni), Common Black-Hawk (Buteogallus anthracinus), American Kestrel (Falco sparverius), Osprey (Pandion haliaetus), and Western Screech-owl (Megascops kennicottii). Cooper’s Hawk was the most abundant nesting raptor with 22 (57%) active nests, Great Horned Owl was the second most common with 9 (19%) active nests. Maintaining a database of active raptor nests helps land managers evaluate ecosystem condition and avoid negative impacts to breeding raptors in the Bosque.

S. David Moore, U.S. Bureau of Reclamation, Denver Technical Service Center

The southwestern willow flycatcher (Empidonax traillii extimus; flycatcher) requires dense stands of preferably native woody riparian vegetation for breeding. The species was federally listed endangered under the Endangered Species Act in 1995 due to a dwindling population caused primarily by habitat loss and degradation. The Bureau of Reclamation, in cooperation with various state and federal entities, has been conducting flycatcher-related studies within the Middle Rio Grande since 1996. These studies, intended to determine population trends and limiting factors to population growth, include presence/absence surveys, nest monitoring, habitat mapping and modeling, and tamarisk beetle impact assessment. Between 1996 and the present, the Middle Rio Grande flycatcher population has grown from less than 20 territories to more than 300. The bulk of this expansion occurred in the exposed pool of Elephant Butte Reservoir when large swaths of native willow habitat developed as the reservoir receded in the early 2000’s. However, smaller populations have been documented upstream. Surveys conducted in 2019 documented 337 flycatcher territories, including 275 breeding pairs. A majority were located in the delta of Elephant Butte Reservoir. Within these territories, a total of 307 nests were monitored. Overall nest success was 42 percent and nests failed primarily due to depredation. Nest abandonment and brown-headed cowbird nest parasitism rates were both low. The increased use of tamarisk habitat for nesting continued, which presents problems considering the recent colonization by tamarisk beetles. However, the relatively wet conditions experienced in 2019 invigorated native riparian habitat while slowing the beetle infestation.

Other Author:
Kristen Dillon, U.S. Bureau of Reclamation, Denver Technical Service Center

Kristen G. Dillon, U.S. Bureau of Reclamation, Denver Technical Service Center

The Western Yellow-billed Cuckoo population is in steep decline due to habitat loss and degradation, and is considered a threatened Distinct Population Segment under the Endangered Species Act. Cuckoos are unique in that they are typically not defensive of their breeding territories and have unusually large, and often overlapping, home ranges. As a result, critical data on the species’ breeding habitat requirements is often conflicting or lacking entirely. The Rio Grande supports one of the largest remaining Western Yellow-billed Cuckoo populations. Bureau of Reclamation biologists delineated 96 territories, based on the locations of 429 detections, between Isleta Pueblo and El Paso in 2019. This population has more than tripled in size since monitoring began in 2006. A radio telemetry study was initiated in 2017 in order to determine home range and habitat requirements of the species, as well as to improve population estimates and model carrying capacity. Twenty-nine cuckoos were captured and instrumented during the first 3 years of the study. Analysis of movement data found that cuckoos breeding on the Middle Rio Grande had an average 50% Kernel Home Range of approximately 7 hectares and an average 95% Kernel Home Range of approximately 38 hectares. However, home range size was also clearly related to habitat availability, such that cuckoos used more habitat if it was available. Cuckoos’ 95% Kernel Home Range averaged approximately 60 hectares in areas with large, continuous patches of habitat, compared to only 18 hectares in areas with smaller and more disjunct habitat patches. Nevertheless, overall territory sizes were similar, averaging approximately 180 hectares, and individuals were observed to travel over a kilometer in a day during the breeding season. Native overstory vegetation comprised a large percentage of breeding territories, disproportionate to its availability on the landscape.

Other Author:
S. David Moore, U.S. Bureau of Reclamation, Denver Technical Service Center

Ondrea Hummel, Tetra Tech

Southwestern Willow Flycatcher (Empidonax traillii extimus; flycatcher) and Western Yellow-billed Cuckoo (Coccyzus americanus occidentalis; cuckoo) population declines are attributed to habitat loss, modification, and degradation. Vast portions of the floodplain have been reduced resulting in reduction of connectivity of potentially suitable habitat. Alterations to the hydraulic regime in the Middle Rio Grande has occurred through the construction of dams, reservoirs, river channelization, bank stabilization, and other flood control structures such as levees and diversions. Surface and groundwater depletion have altered the frequency and magnitude of flows, channel structure, and floodplain connectivity which have also contributed to the alteration and reduction of potential habitat.

Restoration activities, with the potential to provide habitat for these species, have been completed in the Albuquerque Reach of the Rio Grande over the past 15-20 years. Goals of the restoration activities include habitat improvement for all species, but where possible, increasing potential stopover, foraging and/or nesting habitat for both the flycatcher and cuckoo.

To assess the effectiveness of the restoration activities, presence/absence surveys for flycatcher and cuckoo were conducted at 11 locations within the Albuquerque Reach of the Middle Rio Grande Endangered Species Collaborative Program (Program) boundaries from 2017-2019. Locations within the Albuquerque Reach that are evaluated in this study were constructed beginning as early as 2004. Species use and habitat suitability were evaluated for both the flycatcher and cuckoo. Restoration sites are presently in various stages of riparian succession, each with different vegetative species composition and structure, and associated habitat potential for the flycatcher and cuckoo. Trends and results were analyzed, and recommendations for future survey work based on current habitat conditions is also provided. An overview of the survey results, habitat suitability and associated recommendations will be presented.

Other Authors:
Alaina Pershall, Tetra Tech
Chris Sanderson, Tetra Tech
Joe Schroeder, Tetra Tech

Nathan Schroeder, Pueblo of Santa Ana

The Pueblo’s restoration within the Rio Grande and Jemez riparian corridors attempt to reestablish natural trajectories in vegetation composition and structure. Based on reference data, the Pueblo can categorize restoration sites. The Pueblo deployed between 34 to 40 Hobo U23 probes per year (2010 – 2012) to collect temperature and relative humidity data (collected every 15 minutes). Each Hobo location had associated soil moisture readings collected every two weeks. Data was collected from May 12th to August 15th, timed to coincide with when willow flycatchers are on their breeding grounds. Four site categories were selected based on historic data, field observations, and restoration activities: high flycatcher use, non-use by flycatchers, “passive” restoration, and active restoration sites. Pueblo staff collected vegetation structure and composition data from circular plots with 11.3-m radii centered on the focal tree where Hobo’s were located. Vegetation composition was similar, but dominance of native species varied between the four groups. High use and passive restoration sites were dominated by native species, non-use by mixed native and exotic species, and active restoration by coyote willow. Active restoration site dominance by coyote willow resulted in vertical foliage volumes that were quite different from the other groups. The foliage volume pattern between high use and passive restoration sites were similar (highest between two and nine meters). Non-use sites had the highest volume of foliage in the bottom three meters and were dominated by non-native species. Temperature variation was less in passive restoration sites than high use sites while high use had less variation than non-use. Relative humidity was higher in high use sites than non-used sites and in active restoration sites than passive restoration sites. Average soil moisture was greater in high use than non-use sites. These results indicate major differences in the four categories of habitat and provide a better model for restoration.

Other Author:
Cathy Nishida, Pueblo of Santa Ana

Michael Scialdone, Pueblo of Sandia

Ravenna grass (Tripidium ravennae) is a relatively new invasive non-native plant to come into the bosque of the Middle Rio Grande Valley. It is aggressive and persistent, able to crowd out native species and become a monoculture. The nature of the plant with long, thin leaves that quickly dry out and tall stems leading to ‘fluffy’ seed heads, make it a very potent fire spreader if in an area where a fire starts. The Pueblo of Sandia began efforts to control a large Ravenna grass infestation in its bosque about 5 years ago with a strategy of containment. A contractor was hired to spray imazapyr on the outer-most plants of the main infestation and hitting isolated plants and patches, which worked. More recently, a grant was awarded to the Pueblo through BIA’s Invasive Species Program and the strategy changed to one of elimination. Two different youth corps were hired, one for spring and one for fall. The first mowed the Ravenna grass with brush saws and began digging up the plants that were too close to cottonwoods to safely spray the Ravenna grass without killing the cottonwood. The plan was to let it resprout over the summer and come back with the second youth corps to spray the resprouts. However, the digging process went well and was continued in the fall. Like dealing with any non-native, persistence is most important. Herbicide (imazapyr) and digging were both effective. The site will be monitored over 2020 and follow-up will be done in the fall if needed.

Todd Caplan, GeoSystems Analysis

This presentation provides a case study demonstrating that maintaining ecological functions of Middle Rio Grande habitat restoration projects through a coordinated monitoring and adaptive management strategy is an essential step towards achieving recovery goals for the federally endangered Rio Grande silvery minnow. Eleven restoration projects were constructed between 2016 and 2019 along a 30-mile river reach between Sevilleta National Wildlife Refuge and Socorro, NM. All projects involved mechanically lowering elevated floodplain terraces to promote overbank inundation at discharges between 800cfs and 2000cfs. The chief objective was to create favorable habitat conditions for spawning and rearing silvery minnow along river segments with inherently low channel habitat complexity. While all eleven projects were designed to provide off-channel habitat at low to moderate discharges, the construction period coincided with above average and prolonged snowmelt runoff. A comprehensive effectiveness monitoring program documented that biological and physical success criteria were achieved at the design discharge, but that sediment plugs deposited along backwater channel inlets would prevent all project sites from functioning at the design discharge without adaptive management intervention. Nonetheless, topographic surveys revealed that the volume of deposited sediment was relatively small compared to amount removed during construction. These data demonstrate that modest funding is required to remove these sediment plugs and extend the functional life of these projects.

Other Authors:
Grace Haggerty, N.M. Interstate Stream Commission
Chad McKenna, GeoSystems Analysis
Mark Stone, University of New Mexico

David Pizzi, Tetra Tech

How sediment moves through the Middle Rio Grande (MRG) is an important planning and engineering consideration because it influences a range of concerns, including flood risk reduction and river rehabilitation (Jepsen et al. 2003). Further, a sediment imbalance may impair the riverine and riparian ecosystems that are vital to endangered species. The U.S. Army Corps of Engineers, Albuquerque District, recently completed the development and application of a one-dimensional sediment transport model (HEC-RAS) to evaluate potential future geomorphic and sedimentation trends in reaches of the MRG. The model was developed with continuity of parameters between Cochiti Dam and Elephant Butte Reservoir to provide consistency across diversion dams that have historically segregated modeling reaches and reset modeling boundary conditions. The simulated results provide insight on the potential future magnitude and gradation of sediment transported in the MRG, as well as temporal and spatial changes in the channel bed elevation and stored sediment volumes. Some key interpretations of results that may impact endangered species habitat include:

• Bed lowering/channel widening in response to expected decrease in sediment storage from Cochiti to Angostura, Isleta to Bernardo, and in the downstream portion of the San Acacia reach
• Bed raising/channel narrowing in response to expected increase in sediment storage in other MRG reaches
• Identifying the importance on MRG morphology of:
  • tributary sediment loading
  • hydrologic sequences, such as extended drought
  • anthropogenic influences, such as diversion dams or reservoir pool levels

The model is useful for evaluating scenarios and valuable for supplying boundary conditions in more-detailed modeling of flood risk, sedimentation, or habitat improvement projects. For example, one current application of the model is to provide boundary conditions (magnitude and gradation of sediment delivery) around the Isleta Diversion Dam to investigate potential solutions for sedimentation problems and design of Rio Grande silvery minnow passage.

Other Authors:
Jonathan AuBuchon, U.S. Army Corps of Engineers, Albuquerque District
Ryan Gronewold, U.S. Army Corps of Engineers, Albuquerque District
Stephen Scissons, U.S. Army Corps of Engineers, Albuquerque District
Walt Kuhn, Tetra Tech

Kyle Stark, U.S. Army Corps of Engineers

Habitat restoration features constructed on the Middle Rio Grande (MRG) through Albuquerque have focused on removing non-native vegetation, encouraging endangered species habitat, and promoting a main channel to floodplain connection. To date, only three locations have been assessed over several years with respect to their functionality and long-term performance. In 2018 and 2019, an additional 14 sites were assessed to establish a baseline condition and evaluate the changes caused by the snow-melt runoff in 2019.

The morphological changes that occur through sedimentation in the habitat restoration features were evaluated using repeat surveys conducted both parallel and perpendicular to the flow. Deposition of sediment, which can reduce the effective inundation, can then be assessed. Initial results for all 17 sites indicate a general pattern of deposition in all overbanking feature types (high flow channels, bank terraces, interconnected swales, etc.). The greatest morphological change has been observed at entrance and exits of high-flow channels. Observation of the sites after the 2019 snow-melt runoff indicates that overbanking flows bring in sediment and also invigorate native riparian vegetation. Based on an initial assessment of the field surveys, a combination of feature types may best promote habitat for endangered species. For example, large bank terracing features promote ample vegetation growth along the Rio Grande, while inland swales connected via backflow channels provide spawning habitat throughout the riparian zone.

Overall, the habitat restoration sites evaluated on the MRG through Albuquerque have successfully encouraged more native riparian growth, created habitat development, and increased the river’s connection with its floodplain. These projects benefit their community in other ways as well; they are often used by local residents or recreation and teaching. With an increased use and appreciation of the MRG Bosque, future generations of endangered species and humans also benefit.

Other Authors:
Jonathan AuBuchon, U.S. Army Corps of Engineers
Lynette M. Giesen, U.S. Army Corps of Engineers

Chad McKenna, GeoSystems Analysis

Habitat restoration is one of the critical needs for ESA-listed species in the MRG and a number of projects have been completed by signatory members of the MRGESCP, with previous work areas spanning more than 10,000 acres and other projects planned in all four of the MRG reaches (Cochiti, Angostura/Albuquerque, Isleta, and San Acacia). Projects include restoring native riparian vegetation communities, reconnection of the floodplain and channel, increasing channel diversity, and providing refugial habitats. Under contract with NMISC, GeoSystems Analysis recently created a habitat restoration geo-database to document, consolidate, and communicate activities to date. The geo-database includes a highly detailed site attribute table that thoroughly documents construction activities, target beneficiary species, design elements, and monitoring completed. This tool provides valuable information for planning and implementing habitat restoration projects in the future and should be updated as new projects are completed. This presentation will provide an overview of the development process, summary of the sites identified, sample products that can be created with the tool, and recommended next steps.

Keara Bixby, Bosque Ecosystem Monitoring Program

Tamarix spp. (tamarisk, saltcedar) is one of the most successful invasive riparian species since its introduction in the 1800s; as such, it is favored for removal due to its efficient bwater use in comparison with native species (Warren et al. 1975). In an effort to control tamarisk, the specialist defoliator Diorhabda spp. (Tamarisk Leaf Beetle, TLB) was introduced in 2001. After Diorhabda rapidly spread across the Southwest, the Bosque Ecosystem Monitoring Program (BEMP) began monitoring the beetles’ distribution, abundance, and defoliation impact on select tamarisk trees. Since 2013, BEMP has collected TLB at 16-27 sites spanning 270 miles of the Middle Rio Grande riparian forest, locally known as the “bosque”. Over the past seven years, in conjunction with BEMP’s long-term vegetation and litterfall data sets, we observed changes in tamarisk phenology, cyclical patterns of beetle emergence, and decreasing coverage of tamarisk across monitored BEMP sites.

With the integration of the beetle into the Middle Rio Grande, concerns for changes in the microclimate from defoliation have emerged, especially as pertains to the endangered Southwestern Willow Flycatcher (SWFL) (Dudley et al. 2004). With the reduction of native willow stands, tamarisk stands are used as nesting habitat by SWFL (Dudley et al. 2004). Defoliation by TLB led to measurable declines in this habitat during summer months when chicks are vulnerable to high temperatures and predation. BEMP aims to continue monitoring this defoliator to help better understand its impacts on tamarisk stands, changes in vegetation due to tamarisk decline, and best management strategies to assist in habitat recovery for SWFL.

Other Authors:
Kim Eichhorst, Bosque Ecosystem Monitoring Program
Ara Winter, Bosque Ecosystem Monitoring Program
Kim Fike, Bosque Ecosystem Monitoring Program

Chad McKenna, GeoSystems Analysis

Active channel modifications and decreased water availability have significantly reduced geomorphic complexity and floodplain inundation regularity and extent along much of Middle Rio Grande (MRG). These hydro-geomorphic changes have been a principal cause in the loss of native riparian, wetland, and aquatic habitats and associated fish and wildlife species. Rehabilitation efforts along the MRG are increasingly focused on expanding the availability of suitable spawning and breeding habitat for the federally endangered southwestern willow flycatcher (flycatcher; Empidonax traillii extimus) and Rio Grande silvery minnow (RGSM; Hybognathus amarus), plus the federally threatened yellow billed cuckoo (cuckoo; Coccyzus americanus). It is generally well accepted that RGSM nursery habitat attributes include inundated sites with low flow velocities and relatively warm, shallow water that provides food resources and safe zones for larvae. If dense woody vegetation colonizes these sites, they can also mature into desirable habitat conditions for the flycatcher and cuckoo.

Since 2003, the MRGESCP has created or restored about 1600 ha of habitat under a water depletion-neutral framework that mechanically modifies banklines, islands, and historic floodplains to create new backwaters, channels, terraces, and swales designed to inundate at discharges of 500 cfs to 3500 cfs. More than 450 features ranging 0.1–8 ha in size have been constructed in the MRG as habitats designed to seasonally inundate and entrain eggs and larvae of RGSM in spring and to restore floodplain dynamics and native vegetation. Numerous challenges, both expected and unexpected, were faced prior to, during, and after project implementation. This presentation includes an overview of implementation techniques utilized during previous projects and a synopsis of challenges and lessons learned with recommendations for improving project success.

Other Author:
Todd Caplan, GeoSystems Analysis

Matthew J. Johnson, Northern Arizona University

From 2012 through 2019, tamarisk leaf beetle (Diorhabda spp.) surveys and tamarisk habitat evaluations have been conducted throughout the Rio Grande, NM watershed. Over an eight year period, we have tracked tamarisk leaf beetle distribution and tamarisk phenology (defoliation, mortality and flowering). We have also completed genetic analysis of tamarisk leaf beetle species within the watershed and have identified four species; Northern tamarisk leaf beetle (D. carinulata) and Subtropical tamarisk leaf beetle (D.sublineata); Mediterranean tamarisk leaf beetle (D. elongata) and Larger tamarisk leaf beetle (D. carinata). Through our genetic analysis we have also identified tamarisk leaf beetle hybridization among the identified species. During this presentation, we will discuss tamarisk leaf beetle yearly distribution variation among years. We will also discuss the interaction of each species identified within the Rio Grande watershed and how each species is effecting tamarisk habitat and how beetle hybridization may affect future beetle populations. We will also discuss the relationship between tamarisk leaf beetle presence and tamarisk tree phenology (defoliation, branch mortality and flowing) and how these phenological variables have changed within and between years.

Other Author:
Levi Jamison, Jamison Research

Ondrea Hummel, Tetra Tech

The introduction and proliferation of tamarisk leaf beetle (Diorhabda spp.) [TLB] for the biological control of tamarisk (Tamarix spp.) since 2001 has initiated landscape-scale compositional shifts in riparian vegetation communities and altered habitat conditions. TLB populations in the Middle Rio Grande have increased from 2015 through 2018 with overall effects on tamarisk dominated habitat. This increase is mainly due the presence of the Northern TLB (Diorhabda carinulata) that arrived in 2012 and the Subtropical TLB (Diorhabda sublineata) that expanded range into New Mexico from Texas in 2015.

The biocontrol of tamarisk may result in a reduction of habitat and population decline for the Southwestern Willow Flycatcher (Empidonax traillii extimus) [flycatcher] and/or Yellow-billed Cuckoo (Coccyzus americanus) [cuckoo]. Moreover, reductions in tamarisk vegetative cover may result in increased Russian olive (Elaeagnusangustifolia) abundance and additional management problems.

In 2017, the study was initiated to analyze TLB related changes to tamarisk-dominated habitat, examine specific locations the study area over time using remote sensing (RS), and field monitoring of vegetative and avian communities. Vegetation data was collected at 30 selected locations in 2017; avian population data was collected in 2018; and TLB data was collected in both 2017 and 2018. Data was collected in order to understand baseline conditions, ongoing effects of TLB use, and provide a reference to post-treatment patterns and dynamics related to vegetation composition and structure, and associated habitat conditions. The study documents system responses related to riparian habitat structure and plant community alterations (based upon TLB use over time), as well as resulting possible changes to avian species richness and density. The ongoing monitoring of riparian systems altered by TLB is critical to understand management implications to vegetation and the avian community, especially the flycatcher.

Other Authors:
Chris Sanderson, Tetra Tech
Matt Johnson, Northern Arizona University
Eduardo Gonzalez, Department of Biology, Colorado State University
Patrick Shafroth, Fort Collins Science Center, U.S. Geological Survey