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USGS2024

Challenges creating monarch butterfly management strategies for electric power companies in the United States

Returning monarch butterflies ( Danaus plexippus ) to sustainable levels of abundance will require an array of contributors to protect and restore habitat over broad areas. Due to the diversity and scale of land managed by electric power companies across the monarch range, plus an additional 32 million hectares needed for new solar arrays by 2050 to meet renewable energy goals, the industry may have potential to contribute to monarch conservation. However, it is challenging to clearly understand an individual company’s potential for monarch conservation because of the scale and distribution of their specific land assets (ranging from 4,800 to 240,000 hectares in this study alone), the complexity of monarch science, and the lack of a science-based approach for evaluating large land assets for monarch habitat. With monarchs potentially being protected under the United States Endangered Species Act in the future and thereby limiting land management approaches, there is interest from electric power companies to understand how their lands relate to monarchs. In collaboration with companies, we developed a GIS-based model to identify company landholdings that contain high-quality monarch habitat and applied the model to specific landholdings of eight power companies in the United States. We then facilitated discussions with company teams to balance conservation goals, corporate risk, and social opinion. This paper describes non-confidential results for developing a national GIS-based monarch habitat model and applying it to electric power companies who are considering monarch conservation while simultaneously transitioning to a new clean energy future. The model and applied experience may be useful for other organizations working across large landscapes to manage monarchs.

conterminous United States↗

USGS2026

Assessing working lands as habitat for disturbance-dependent birds using autonomous recording units

Introduction Working lands can provide habitat for declining disturbance-dependent birds, such as Bachman's Sparrow ( Peucaea aestivalis ) and Northern Bobwhite ( Colinus virginianus ), but it remains unclear whether restoration following intensive land use (e.g. surface mining) yields habitat comparable to less intensive land uses (e.g. timber production). Objectives We evaluated effects of land use both in working lands (recently replanted surface mine reclamation site and recently replanted timber production site) and reference sites explicitly managed for wildlife (recently restored young pine savanna and mature pine savanna) and understory vegetation characteristics on relative abundance of disturbance-dependent birds within upland pine ( Pinus spp.) communities in southeastern Georgia, United States. We hypothesized that the mine reclamation site would support similar bird species but in lower relative abundances than other land uses. Methods We conducted daily acoustic surveys using autonomous recording units (ARUs) and measured vegetation surveys once per point from May to June 2024. We used Royle-Nichols models, an adapted occupancy model, to estimate relative abundance for eight bird species. Results Land use influenced relative abundance for all species and explained more variation in relative abundance than measured understory vegetation characteristics. The mining reclamation site supported most disturbance-dependent species and, in some cases, equal or higher relative abundances, particularly for Northern Bobwhite and Common Nighthawk ( Chordeiles minor ). Responses across timber production and savanna sites varied by species. Vegetation effects were generally weaker and species-specific, suggesting that land use history and associated habitat legacies play an important role in structuring these bird communities. Conclusion Working lands, including reclaimed mines, can provide habitat for disturbance-dependent birds, and ARUs are effective for evaluating these patterns across land uses.

Restoration Ecology↗

USGS2019

Multi-element fingerprinting of waters to evaluate connectivity among depressional wetlands

Establishing the connectivity among depressional wetlands is important for their proper management, conservation and restoration. In this study, the concentrations of 38 elements in surface water and porewater of depressional wetlands were investigated to determine chemical and hydrological connectivity of three hydrological types: recharge, flow-through, and discharge, in the Prairie Pothole Region of North America. Most element concentrations of porewater varied significantly by wetland hydrologic type ( p < 0.05), and increased along a recharge to discharge hydrologic gradient. Significant spatial variation of element concentrations in surface water was observed in discharge wetlands. Generally, higher element concentrations occurred in natural wetlands compared to wetlands with known disturbances (previous drainage and grazing). Electrical conductivity explained 42.3% and 30.5% of the variation of all element concentrations in porewater and surface water. Non-metric multidimensional scaling analysis showed that the similarity decreased from recharge to flow-through to discharge wetland in each sampling site. Cluster analysis confirmed that element compositions in porewater of interconnected wetlands were more similar to each other than to those of wetlands located farther away. Porewater and surface water in a restored wetland showed similar multi-element characteristics to natural wetlands. In contrast, depressional wetlands connected by seeps along a deactivated drain-tile path and a grazed wetland showed distinctly different multi-element characteristics compared to other wetlands sampled. Our findings confirm that the multi-element fingerprinting method can be useful for assessing hydro-chemical connectivity across the landscape, and indicate that element concentrations are not only affected by land use, but also by hydrological characteristics.

North Dakota↗

USGS2023

Fecal metabarcoding of the endangered Pacific pocket mouse (Perognathus longimembris pacificus) reveals a diverse and forb rich diet that reflects local habitat availability

Information on diet breadth and preference can assist in understanding links between food resources and population growth and inform habitat restoration for rare herbivores. We assessed the diet of the endangered Pacific pocket mouse using metabarcoding of fecal samples and compared it to plant community composition in long-term study plots in two populations on Marine Corps Base Camp Pendleton, San Diego County, CA. Fecal samples ( n = 221) were collected between spring 2016 and fall 2017 during monthly live-trap surveys. Concurrently, percent cover and plant phenology were measured in plots centered on trap locations. Fecal samples were sequenced with paired-end reads of the internal transcribed spacer 2 region of the nuclear ribosomal gene, and the resulting amplicons were matched to a regionally specific database. Seventy-three plant taxa were detected, which were mostly forbs and perennial herbs (70–90%). Diet composition differed between populations, years, seasons, and plots. Overall, diet and local habitat composition in plots were significantly correlated. However, we detected some differences in above-ground seed availability and proportion in fecal samples that indicate diet preferences for some forbs, perennial herbs, and native bunch grasses over perennial shrubs and non-native grasses. This is the first study of PPM to pair plant phenology surveys with diet metabarcoding to estimate resource selection, and results suggest that managing habitat for diverse native forb communities and reducing non-native grass cover may be beneficial for this critically endangered species.

California↗

USGS2023

Sage-grouse

In this chapter, we summarize the ecology and conservation issues affecting greater ( Centrocercus urophasianus ) and Gunnison ( C . minimus ) sage-grouse, iconic and obligate species of rangelands in the sagebrush ( Artemisia spp.) biome in western North America. Greater sage-grouse are noted for their ability to migrate, whereas Gunnison sage-grouse localize near leks year-round. Seasonal habitats include breeding habitat where males display at communal leks, nesting habitat composed of dense sagebrush and herbaceous plants to conceal nests, mesic summer habitats where broods are reared, and winter habitat, characterized by access to sagebrush for cover and forage. While two-thirds of sage-grouse habitat occurs on public lands, private land conservation is the focus of national groups including the USDA-NRCS Sage-Grouse Initiative. Sage-grouse are a species of great conservation concern due to population declines associated with loss and fragmentation of more than half of the sagebrush biome. Wildlife and land management agencies have been increasingly proactive in monitoring trends in sage-grouse populations (e.g., lek count index), adapting regulations to reduce harvest on declining populations, and in designing and implementing conservation policies such as core areas to conserve sage-grouse habitats and populations. Much of the remaining sagebrush habitat is threatened by altered fire regimes, invasive annual grasses and noxious weeds, encroaching piñon ( Pinus edulis and monophylla )-juniper ( Juniperus spp.) woodlands, sagebrush conversion, anthropogenic development, and climate change. Several diseases affect sage-grouse, but to date, disease has not been a widespread cause of declines. Proper livestock grazing and limited hunting appear to be sustainable with sage-grouse, whereas improper grazing, increasing free-roaming equid populations, and sagebrush conversion are primary concerns for future conservation. Research has identified additional concerns for sage-grouse including effects from fence collisions, predation from common ravens ( Corvus corax ), and reduced habitat effectiveness resulting from grouse avoidance of anthropogenic infrastructure. There is a need for future research evaluating sage-grouse habitat restoration practices following improper rangeland management, habitat alteration from invasive species and fire, effects on small and isolated populations, and effects from diseases.

Book chapter↗

USGS2019

Water salinity and inundation control soil carbon decomposition during salt marsh restoration: An incubation experiment

Coastal wetlands are a significant carbon (C) sink since they store carbon in anoxic soils. This ecosystem service is impacted by hydrologic alteration and management of these coastal habitats. Efforts to restore tidal flow to former salt marshes have increased in recent decades and are generally associated with alteration of water inundation levels and salinity. This study examined the effect of water level and salinity changes on soil organic matter decomposition during a 60‐day incubation period. Intact soil cores from impounded fresh water marsh and salt marsh were incubated after addition of either sea water or fresh water under flooded and drained water levels. Elevating fresh water marsh salinity to 6 to 9 ppt enhanced CO 2 emission by 50%−80% and most typically decreased CH 4 emissions, whereas, decreasing the salinity from 26 ppt to 19 ppt in salt marsh soils had no effect on CO 2 or CH 4 fluxes. The effect from altering water levels was more pronounced with drained soil cores emitting ~10‐fold more CO 2 than the flooded treatment in both marsh sediments. Draining soil cores also increased dissolved organic carbon (DOC) concentrations. Stable carbon isotope analysis of CO 2 generated during the incubations of fresh water marsh cores in drained soils demonstrates that relict peat OC that accumulated when the marsh was saline was preferentially oxidized when sea water was introduced. This study suggests that restoration of tidal flow that raises the water level from drained conditions would decrease aerobic decomposition and enhance C sequestration. It is also possible that the restoration would increase soil C decomposition of deeper deposits by anaerobic oxidation, however this impact would be minimal compared to lower emissions expected due to the return of flooding conditions.

Ecology and Evolution↗

USGS2024

Restoration treatments enhance tree growth and alter climatic constraints during extreme drought

The frequency and severity of drought events are predicted to increase due to anthropogenic climate change, with cascading effects across forested ecosystems. Management activities such as forest thinning and prescribed burning, which are often intended to mitigate fire hazard and restore ecosystem processes, may also help promote tree resistance to drought. However, it is unclear whether these treatments remain effective during the most severe drought conditions or whether their impacts differ across environmental gradients. We used tree-ring data from a system of replicated, long-term (>20 years) experiments in the southwestern United States to evaluate the effects of forest restoration treatments (i.e., evidence-based thinning and burning) on annual growth rates (i.e., basal area increment; BAI) of ponderosa pine ( Pinus ponderosa ), a broadly distributed and heavily managed species in western North America. The study sites were established at the onset of the most extreme drought event in at least 1200 years and span much of the climatic niche of Rocky Mountain ponderosa pine. Across sites, tree-level BAI increased due to treatment, where trees in treated units grew 133.1% faster than trees in paired, untreated units. Likewise, trees in treated units grew an average of 85.6% faster than their pre-treatment baseline levels (1985 to ca. 2000), despite warm, dry conditions in the post-treatment period (ca. 2000–2018). Variation in the local competitive environment promoted variation in BAI, and larger trees were the fastest-growing individuals, irrespective of treatment. Tree thinning and prescribed fire altered the climatic constraints on growth, decreasing the effects of belowground moisture availability and increasing the effects of atmospheric evaporative demand over multi-year timescales. Our results illustrate that restoration treatments can enhance tree-level growth across sites spanning ponderosa pine's climatic niche, even during recent, extreme drought events. However, shifting climatic constraints, combined with predicted increases in evaporative demand in the southwestern United States, suggest that the beneficial effects of such treatments on tree growth may wane over the upcoming decades.

Arizona, Colorado, Nevada, New Mexico, Texas↗

USGS2023

A review of natural and managed revegetation responses in two de-watered reservoirs after large dam removals on the Elwha River, Washington, USA

Large dam removals are increasing in frequency and the response of natural and managed revegetation is a critical consideration for managed restoration of dewatered reservoir landscapes post dam removal. The removal of two large dams on the Elwha River in 2011-2014 provides insight into reservoir revegetation. We review literature and datasets from 2012 through 2018, 1-6 years since reservoir dewatering, to compare pre-dam removal predictions on the Elwha to post-dam removal of natural revegetation, managed revegetation effects and invasive non-native vegetation response. Pre-dam removal hypotheses about natural revegetation did not predict species performance on reservoir sediments, seed rain patterns, or seed bank response. Sediment texture and landform affected multiple aspects of revegetation, including vegetation cover, species richness, woody stem densities and species composition. Reservoir drawdown timing influenced species composition and seedling densities. Predictions about managed revegetation effects were mixed. Planting trees and shrubs did not accelerate woody cover but did increase species richness. Seeding reduced non-native vegetation frequency and species richness, had no effect on vegetation cover on fine sediments, but increased vegetation cover on coarse sediments. Planting trees and shrubs during drawdown appeared to result in higher survival rates compared to plantings installed 1+ years post drawdown. Seeding Lupinus rivularis (riverbank lupine) on coarse sediments was successful and increased foliar nitrogen in planted conifers. Invasive non-native vegetation was correctly predicted to be more abundant in the Aldwell reservoir but did not preclude native species establishment in either reservoir, likely due to rapid establishment of native species and robust management that occurred before, during and after dam removal.

Washington↗

USGS2009

Male Kirtland's Warblers' patch-level response to landscape structure during periods of varying population size and habitat amounts

Forest planners must evaluate how spatiotemporal changes in habitat amount and configuration across the landscape as a result of timber management will affect species' persistence. However, there are few long-term programs available for evaluation. We investigated the response of male Kirtland's Warbler (Dendroica kirtlandii) to 26 years of changing patch and landscape structure during a large, 26-year forestry-habitat restoration program within the warbler's primary breeding range. We found that the average density of male Kirtland's Warblers was related to a different combination of patch and landscape attributes depending on the species' regional population level and habitat amounts on the landscape (early succession jack pine (Pinus banksiana) forests; 15-42% habitat cover). Specifically, patch age and habitat regeneration type were important at low male population and total habitat amounts, while patch age and distance to an occupied patch were important at relatively high population and habitat amounts. Patch age and size were more important at increasing population levels and an intermediate amount of habitat. The importance of patch age to average male density during all periods reflects the temporal buildup and decline of male numbers as habitat suitability within the patch changed with succession. Habitat selection (i.e., preference for wildfire-regenerated habitat) and availability may explain the importance of habitat type and patch size during lower population and habitat levels. The relationship between male density and distance when there was the most habitat on the landscape and the male population was large and still increasing may be explained by the widening spatial dispersion of the increasing male population at the regional scale. Because creating or preserving habitat is not a random process, management efforts would benefit from more investigations of managed population responses to changes in spatial structure that occur through habitat gain rather than habitat loss to further our empirical understanding of general principles of the fragmentation process and habitat cover threshold effects within dynamic landscapes.

Forest Ecology and Management↗

USGS2021

Rigorously valuing the impact of Hurricanes Irma and Maria on coastal hazard risks in Florida and Puerto Rico

The degradation of coastal habitats, particularly coral reefs, raises risks by increasing the exposure of coastal communities to flooding hazards. In the United States, the physical protective services provided by coral reefs were recently assessed in social and economic terms, with the annual protection provided by U.S. coral reefs off the coasts of the State of Florida and the Commonwealth of Puerto Rico estimated to be more than 9,800 people and $859 million (2010 U.S. dollars). Hurricanes Irma and Maria in 2017 caused widespread damage to coral reefs in the State of Florida and the Commonwealth of Puerto Rico. These damages were measured in post-storm surveys of reefs and assessed in terms of their impact on reef condition and height, which are critical parameters for evaluating the coastal defense benefits of reefs. We combined engineering, ecologic, geospatial, social, and economic data and tools to value the increased risks in Florida and Puerto Rico from hurricane-induced damages to their adjacent coral reefs. We followed risk-based valuation approaches to map flooding at 10-square-meter resolution along all 980 kilometers of Florida and Puerto Rico’s reef-lined shorelines considering reef condition before (undamaged) and after (damaged) the 2017 hurricanes. We quantified the coastal flood risk increase caused by the hurricane-induced damage to the coral reefs using the latest information from the U.S. Census Bureau, Federal Emergency Management Agency, and Bureau of Economic Analysis for return-interval storm events. Using the damages associated with each storm probability, we also calculated the change in annual expected damages, a measure of the annual protection lost because of the reef damage caused by the 2017 hurricanes. We found that the damages to the coral reefs off Florida and Puerto Rico from Hurricanes Irma and Maria increased future risks significantly. In particular, we estimated the protection lost by Florida and Puerto Rico’s coral reefs from the 2017 hurricanes to result in: Increased flooding to more than 10.72 square kilometers (4.14 square miles) of land annually; Increased flooding affecting more than 4,300 people annually; Increased direct damages of more than $57.2 million to more than 1,800 buildings annually; and Increased indirect damages to more $124.3 million in economic activity owing to housing and business damage annually. Thus, the annual value of increased flood risk caused by the damage to Florida and Puerto Rico’s coral reefs from hurricanes in 2017 is more than 4,300 people and $181.5 mil-lion (2010 U.S. dollars) in economic impacts. These data provide stakeholders and decision makers with a spatially explicit, rigorous valuation of how, where, and when the damage from the 2017 hurricanes decreased critical coastal storm flood reduction benefits to Florida and Puerto Rico’s coral reefs. These results help identify areas where reef management, recovery, and restoration could potentially help reduce the risk to, and increase the resiliency of, Florida and Puerto Rico’s coastal communities.

Florida↗

USGS2022

Influence of riparian thinning on trophic pathways supporting stream food webs in forested watersheds

Resource managers seek to thin second-growth riparian forests to address multiple stream and riparian management objectives, including enhancing aquatic productivity via light-mediated trophic pathways in watersheds of the Pacific Northwest (USA). However, such increases in aquatic productivity depend on complex food web dynamics that link riparian forests and streams. To evaluate how riparian forest thinning influences stream food webs, we conducted a replicated, manipulative field experiment in three northern California watersheds composed of second-growth redwood forests and tracked responses across multiple trophic levels (periphyton, macroinvertebrates, amphibians, and fish) 1 year pre- and post-treatment. Riparian thinning treatments increased light to the stream channel, yet we observed mixed responses by stream food webs. Thinning did not change stream periphyton biomass on natural substrates but increased periphyton accrual on ceramic tiles. Periphyton accrual appeared to be partially muted by top-down effects from invertebrate scrapers, which were more abundant in thinned reaches. Prey in the diets of top predators—coastal giant salamanders ( Dicamptodon tenebrosus ) and coastal cutthroat trout ( Oncorhynchus clarkii clarkii )—did not change in biomass, composition, or structure in response to thinning and instead varied more seasonally and between predators. Stable isotope analysis indicated that shifts in carbon (δ 13 C) signatures of stream periphyton associated with thinning were reflected to varying extents by primary consumers but did not propagate up to top predators. Top predator biomass responses varied between species, where salamander biomass remained unchanged, but cutthroat trout biomass increased slightly in thinned reaches. However, trout biomass responses were not supported by diets or isotopes and correlated weakly with changes in light associated with thinning, suggesting little evidence that responses could be attributed directly to changes in autotrophic pathways. Furthermore, we found no evidence that local trophic responses to thinning propagated into downstream reaches. Taken together, we observed that trophic pathways supporting stream food webs remained largely intact immediately after riparian thinning treatments. Collectively, these results suggest that riparian thinning does not necessarily enhance aquatic productivity in forested streams, indicating that contextual factors driving realized ecological responses should be accounted for when considering thinning as a restoration strategy for stream–riparian ecosystems.

California↗

USGS2023

Living on the edge: Predicting songbird response to management and environmental changes across an ecotone

Effective wildlife management requires robust information regarding population status, habitat requirements, and likely responses to changing resource conditions. Single-species management may inadequately conserve communities and result in undesired effects to non-target species. Thus, management can benefit from understanding habitat relationships for multiple species. Pinyon pine and juniper ( Pinus spp. and Juniperus spp.) are expanding into sagebrush-dominated ( Artemisia spp.) ecosystems within North America and mechanical removal of these trees is frequently conducted to restore sagebrush ecosystems and recover Greater Sage-grouse ( Centrocercus urophasianus ). However, pinyon-juniper removal effects on non-target species are poorly understood, and changing pinyon-juniper woodland dynamics, climate, and anthropogenic development may obscure conservation priorities. To better predict responses to changing resource conditions, evaluate non-target effects of pinyon-juniper removal, prioritize species for conservation, and inform species recovery within pinyon-juniper and sagebrush ecosystems, we modeled population trends and density-habitat relationships for four sagebrush-associated, four pinyon-juniper-associated, and three generalist songbird species with respect to these ecosystems. We fit hierarchical population models to point count data collected throughout the western United States from 2008 to 2020. We found regional population changes for 10 of 11 species investigated; 6 of which increased in the highest elevation region of our study. Our models indicate pinyon-juniper removal will benefit Brewer's Sparrow ( Spizella breweri ), Green-tailed Towhee ( Pipilo chlorurus ), and Sage Thrasher ( Oreoscoptes montanus ) densities. Conversely, we predict largest negative effects of pinyon-juniper removal for species occupying early successional pinyon-juniper woodlands: Bewick's Wren ( Thryomanes bewickii ), Black-throated Gray Warblers ( Setophaga nigrescens ), Gray Flycatcher ( Empidonax wrightii ), and Juniper Titmouse ( Baeolophus ridgwayi ). Our results highlight the importance of considering effects to non-target species before implementing large-scale habitat manipulations. Our modeling framework can help prioritize species and regions for conservation action, infer effects of management interventions and a changing environment on wildlife, and help land managers balance habitat requirements across ecosystems.

Ecology and Evolution↗

USGS2020

Postfire growth of seeded and planted big sagebrush - Strategic designs for restoring Greater Sage-grouse nesting habitat

Wildfires change plant community structure and impact wildlife habitat and population dynamics. Recent wildfire‐induced losses of big sagebrush ( Artemisia tridentata ) in North American shrublands are outpacing natural recovery and leading to substantial losses in habitat for sagebrush‐obligate species such as Greater Sage‐grouse. Managers are considering restoration strategies that include planting container‐grown sagebrush to improve establishment within areas using more conventional seeding methods. Although it is thought that planting sagebrush provides initial structural advantages over seeding, empirical comparisons of sagebrush growth are lacking between individuals established post‐fire using both methods. Using a Bayesian hierarchical approach, we evaluated sagebrush height and canopy area growth rates for plants established in 26 seeded and 20 planted locations within the Great Basin. We then related recovery rates to previously published nesting habitat requirements for sage‐grouse. Under average weather conditions, planted or seeded sagebrush will require 3 or 4 years, respectively, and a relatively high density (≥ 2 plants/m 2 ) to achieve the minimum recommended canopy cover for sage‐grouse (15 %). Sagebrush grown in warmer and drier conditions met this cover goal months earlier. Although planted sagebrush reached heights to meet sage‐grouse nesting requirements (30 cm) one year earlier than seeded plants, seeded individuals were ~19 cm taller with 410 cm 2 more canopy area than planted sagebrush after 8 years. However, big sagebrush establishment from seed is unreliable. Strategically planting small, high density patches of container‐grown sagebrush in historic sage‐grouse nesting habitat combined with lower density seedings in larger surrounding areas may accelerate sage‐grouse habitat restoration.

California, Idaho, Nevada, Oregon, Utah↗

USGS2021

Diversity in spawning habitat use among Great Lakes Cisco populations

Cisco ( Coregonus artedi ) once dominated fish communities in the Laurentian Great Lakes. Restoring the abundance and distribution of this species has emerged as a management priority, yet our understanding of Cisco spawning habitat use is insufficient to characterise habitat needs for these populations and assess whether availability of suitable spawning habitat could be a constraint to recovery. We characterised the distribution of incubating Cisco eggs in situ across gradients of depth and substrate types to describe the spawning habitat used by three Great Lakes populations. In Chaumont Bay, Lake Ontario, eggs were concentrated on shallow bedrock shoals and not found on deeper silt or sand substrate. In contrast, eggs in Thunder Bay, Lake Superior, and Elk Rapids, Lake Michigan, were found on deeper fine grain sediments with low utilisation of shallow rocky and cobble habitats. These patterns of egg incubation habitat use suggest a broad spawning habitat niche at the species level but distinct spawning habitat preferences at the population level. While our results indicate some historical diversity in spawning habitat use has been maintained across the species’ range in the Great Lakes, comparisons of contemporary spawning habitat utilisation against historical accounts raise questions as to whether some spawning habitat use behaviours may no longer be prevalent within specific lakes. Thus, characterising the portfolio of spawning strategies remaining within lakes may improve our understanding of habitat needs and identify opportunities to maintain population diversity while supporting Cisco rehabilitation.

Michigan, New York↗

USGS2014

The interactive effects of climate change, riparian management, and a non-native predators on stream-rearing salmon

Predicting how climate change is likely to interact with myriad other stressors that threaten species of conservation concern is an essential challenge in aquatic ecosystems. This study provides a framework to accomplish this task in salmon-bearing streams of the northwestern United States, where land-use related reductions in riparian shading have caused changes in stream thermal regimes, and additional warming from projected climate change may result in significant losses of coldwater fish habitat over the next century. Predatory non-native smallmouth bass have also been introduced into many northwestern streams and their range is likely to expand as streams warm, presenting an additional challenge to the persistence of threatened Pacific salmon. The goal of this work was to forecast the interactive effects of climate change, riparian management, and non-native species on stream-rearing salmon, and to evaluate the capacity of restoration to mitigate these effects. We intersected downscaled global climate forecasts with a local-scale water temperature model to predict mid- and end-of-century temperatures in streams in the Columbia River basin; we compared one stream that is thermally impaired due to the loss of riparian vegetation and another that is cooler and has a largely intact riparian corridor. Using the forecasted stream temperatures in conjunction with fish-habitat models, we predicted how stream-rearing Chinook salmon and bass distributions would change as each stream warmed. In the highly modified stream, end-of-century warming may cause near total loss of Chinook salmon rearing habitat and a complete invasion of the upper watershed by bass. In the less modified stream, bass were thermally restricted from the upstream-most areas. In both systems, temperature increases resulted in higher predicted spatial overlap between stream-rearing Chinook salmon and potentially predatory bass in the early summer (2-4-fold increase) and greater abundance of bass. We found that riparian restoration could prevent the extirpation of Chinook salmon from the more altered stream, and could also restrict bass from occupying the upper 31 km of salmon rearing habitat. The proposed methodology and model predictions are critical for prioritizing climate-change adaptation strategies before salmonids are exposed to both warmer water and greater predation risk by non-native species.

Oregon↗

USGS2001

Effects of disease, dispersal, and area on bighorn sheep restoration

We simulated population dynamics of bighorn sheep ( Ovis canadensis ) inhabiting six discrete habitat patches in the Badlands ecosystem, South Dakota. Modeled populations were subjected to a range of potential management actions and rates of disease-causing infection. Simulated disease varied in severity from mild (∼12% mortality) to severe (∼67% mortality), with infections imposed once, at regular intervals, or with a fixed probability each year. In the absence of disease, 200-year extinction rates were uniformly low and insensitive to changes in colonization rate or area of suitable habitat. A single infection, accompanied by change in the area of suitable habitat or colonization rate, resulted in extinction rates of up to 40%, and large changes in average population size (up to 10-fold with changes in area; 4-fold with changes in colonization rate). Simulations with multiple infections, which are probably most realistic, generally resulted in extinction rates that exceeded 20% over a 200-year period. Model results clearly showed that efforts directed toward reducing the frequency or severity of disease are of highest priority for improving the success of attempts to restore bighorn sheep populations. Increases in areas of suitable habitat or improvements to corridors between existing habitat patches were far less likely to improve persistence of simulated sheep populations than reductions in the impact of disease. Although theory predicts that enhanced movements may exacerbate effects of disease, increased colonization rates resulted in relatively small but consistent increases in persistence and average population size for all combinations of parameters we examined.

Restoration Ecology↗

USGS2025

Risks and rewards of pre-emergent herbicide (indaziflam) to defend core sagebrush-steppe ecosystems under suboptimal precipitation

Protection of intact habitat from the spread of invasive plants is a global priority, especially where invaders alter wildfire occurrence. Invasion of perennial sagebrush-steppe ecosystems by cheatgrass and other fire-promoting exotic annual grasses (EAGs) is one of the most notorious examples of this problem. Protection and expansion of the remaining intact “core” sagebrush areas are key management goals, and whether this can be accomplished by temporarily inhibiting annual plant populations with pre-emergent herbicides is a key question. We applied indaziflam in fall 2019 to replicate plots within two sagebrush-steppe sites in the Northern Great Basin, USA: 1) a relatively intact, uninvaded, unburned “core” site and 2) a partially invaded site that burned in the 2015 Soda Wildfire. Vegetation cover, density, and growth responses of native perennials were measured annually to 2024. We asked whether our treatments “defended” and “grew” core sagebrush areas. EAG cover remained <15% in indaziflam-treated plots while increasing to >30% in control plots by the fifth year after treatment at the unburned site but did not differ with treatment at the burned site. Native perennial grasses, forbs, and big sagebrush cover and growth did not differ with indaziflam treatment at either site. Moss cover was temporarily lower in indaziflam-treated plots at the unburned site, and cover of a native annual forb was significantly lower in indaziflam-treated plots throughout the study across both sites. Despite posttreatment drought and apparent patchiness in treatment implementation, our treatments “defended the core” by preventing crossing of the 20% EAG invasion threshold in the unburned site but not did not “grow the core.” Our results provide an example of a case in which proactive protection may be easier to accomplish than reactive restoration. Herbicide treatment effects may be sensitive to weather and application details. Implementation monitoring could help explain variability and improve success.

Idaho↗

USGS2013

Comparison of bird community indices for riparian restoration planning and monitoring

The use of a bird community index that characterizes ecosystem integrity is very attractive to conservation planners and habitat managers, particularly in the absence of any single focal species. In riparian areas of the western USA, several attempts at arriving at a community index signifying a functioning riparian bird community have been made previously, mostly resorting to expert opinions or national conservation rankings for species weights. Because extensive local and regional bird monitoring data were available for Nevada, we were able to develop three different indices that were derived empirically, rather than from expert opinion. We formally examined the use of three species weighting schemes in comparison with simple species richness, using different definitions of riparian species assemblage size, for the purpose of predicting community response to changes in vegetation structure from riparian restoration. For the three indices, species were weighted according to the following criteria: (1) the degree of riparian habitat specialization based on regional data, (2) the relative conservation ranking of landbird species, and (3) the degree to which a species is under-represented compared to the regional species pool for riparian areas. To evaluate the usefulness of these indices for habitat restoration planning and monitoring, we modeled them using habitat variables that are expected to respond to riparian restoration efforts, using data from 64 sampling sites in the Walker River Basin in Nevada and California. We found that none of the species-weighting schemes performed any better as an index for evaluating overall habitat condition than using species richness alone as a community index. Based on our findings, the use of a fairly complete list of 30–35 riparian specialists appears to be the best indicator group for predicting the response of bird communities to the restoration of riparian vegetation.

Nevada↗