Eastern Oregon University

Lay Summary Heat stress is a major challenge for beef cattle raised on pasture, reducing cattle health, productivity, and comfort. Electrolyte supplements can be used to support hydration and metabolism, but their effectiveness has not been well studied in grazing beef cows. We tested whether adding an electrolyte solution to the drinking water of pregnant beef cows during late summer could improve hydration, heat tolerance, or overall performance. Fifty-four cows grazed bermudagrass pastures for about 90 days before calving and received either plain water or water mixed with an electrolyte product. The electrolyte supplement did not change water intake, body weight, body condition score, internal temperature, or respiration rate. However, cows receiving electrolytes showed improved hydration and acid–base balance, based on blood measurements. These cows also consumed less loose mineral mix, which may have reduced the overall impact of electrolyte supplementation.

Rangelands are extensive ecosystems, providing important ecosystem services while undergoing continuous change. As a result, improved monitoring technologies can help better characterize vegetation change. Satellite remote sensing has proven effective in this regard, tracking vegetation dynamics at broad and fine scales. We leveraged the spatial, spectral, and temporal resolution of Sentinel-2 satellites to estimate fractional cover and canopy gap across rangelands of the western United States. We produced annual, 10 m spatial resolution estimates of fractional cover and canopy gap size class for years 2018 to 2024. Fractional cover estimates include that of common plant functional types (annual forb and grass, bareground, littler, perennial forb and grass, shrub, tree) and select genera (including invasive annual grass species, pinyon-juniper species, and sagebrush species); canopy gap size classes include gap sizes 25 to 50, 51 to 100, 101 to 200, and greater than 200 cm. We make these data available as Cloud Optimized GeoTIFFs, organized as 75 × 75 km tiles covering the 17 western states of the United States.

ABSTRACT Aim Mountain ecosystems are experiencing increased invasion of non‐native plants. These increases in non‐native species put mountains at risk of biotic homogenisation and a reduction of biodiversity. Our study aims to test if non‐native plant species are contributing to biotic homogenisation along roadways in mountain regions and how this changes along elevation gradients and across spatial scales. Location 18 globally distributed mountain regions. Time Period 2012–2023. Major Taxa Studied Vascular plants. Methods We used standardised vegetation surveys including species cover from 18 mountain regions worldwide to analyse whether the addition of non‐native species to the native flora increased or decreased Bray–Curtis dissimilarity (i.e., beta‐diversity) among roadside plant communities along elevation gradients ranging from 15 to 3919 m a.s.l. We tested this at the local, regional, continental and global scales using mixed‐effects models and confirmed it using null models. Results In the New World, we mainly observed homogenisation across regions and scales, as beta‐diversity was mostly lower with the addition of non‐native species. This was particularly true for low elevations. In contrast, we predominantly found community differentiation in the Old World, specifically at smaller (i.e., local and regional) scales. At the global scale, communities became more similar through the addition of non‐native species at all elevations. Main Conclusions Large‐scale homogenisation might be interpreted as a signal that high‐elevation plant communities along roadways may become more similar as non‐native species continue to spread upwards. Future studies should investigate the mechanisms driving the observed patterns of both homogenisation and differentiation by non‐native species, and explore the potential consequences of these patterns for ecosystem function and resilience.

Abstract Background Catastrophic wildfire has escalated across the globe in recent decades with devastating consequences for human communities and native ecosystems. Global change processes, including climate warming and land use practices, are altering fuels, fire risk, and ecosystem recovery. Managing ecosystems to reduce fire risk and prevent conversion to undesirable alternative states requires knowledge of the ecological conditions of ecosystems, trajectories of change, and drivers of those changes. We developed an approach for evaluating ongoing changes in climate and vegetation and using that information to determine appropriate fuels and other vegetation management strategies for southwest US dryland shrubland and woodland landscapes. We illustrated the approach at a management appropriate scale—a USDA Forest Service Wildfire Crisis Strategy landscape. Results We developed an understanding of ecological types, current climatic regimes, ecological resilience to disturbance, and resistance to invasive annual grass (R&R). We then evaluated changes in plant functional type cover, historical fires, and R&R using long-term data. In unburned areas, changes in plant functional type cover included decreases in perennial forbs and grasses but increases in annual forbs and grasses, shrubs, and especially pinyon and juniper trees. In burned areas, tree cover was reduced and both perennial forb and grass and annual forb and grass cover increased. Most ecological types had moderate wildfire risk based on modeled annual burn probabilities and large areas burned since 1998 (16% of study area). These types were likely burning within expected fire return intervals, but areas burned during a single event may have exceeded historical extents and post-fire outcomes had changed. Transitions to warmer temperature regimes occurred between 1980–1999 and 2000–2019 resulting in an 11% decrease in R&R with the greatest impacts in cooler and moister ecological types. Conclusions We showed that climate warming in southwest drylands has been associated with concurrent changes in vegetation and fuels and decreases in R&R. We provide an approach that allows managers to quantify the ongoing changes at management appropriate scales. We suggest climate smart management strategies to help direct ecosystems into conditions that can decrease fire risk, increase resistance to plant invasions, and reduce vulnerability to climate change.

Abstract Objective We assessed the relative proportions of wild- and hatchery-origin summer steelhead Oncorhynchus mykiss caught by sport anglers in the Deschutes River, Oregon. Our objective was to evaluate if steelhead of wild or hatchery origin were equally or disproportionately captured by sport anglers relative to the overall run composition. Methods We conducted access-based angler creel surveys of the Deschutes River steelhead fishery during 2000–2019 and 2021 to observe reported catch of wild and hatchery steelhead. We collated fishery-independent hatchery-wild composition data from three locations (two dams and one fish trap) bounding the fishery area we creel sampled. We then used a series of mixed-effect logistic regression models fit to compare angler catch of wild- and hatchery-origin steelhead relative to their composition at the fishery-independent sampling locations. Result The best-fit model suggests that anglers were more than twice as likely to observe a wild steelhead in their catch as compared with the chance of the fishery-dependent sampling sites to observe a wild steelhead. Across all years, wild steelhead were 27–31% of the stock composition at the fishery-independent sampling sites yet averaged 65% of angler catch. Conclusion Disproportionately high encounter rates of wild-origin summer steelhead suggest that any adverse impacts associated with catch-and-release fishing may be magnified by this effect. We explore some potential mechanisms that could account for this difference and hypothesize that a difference in catchability between wild and hatchery steelhead is the most likely mechanism driving the observed patterns. Regardless of the mechanism, annual catch of wild steelhead is proportionally greater than expectations, given wild steelhead run size compared with that of hatchery steelhead.

Rapid climate change poses a fundamental challenge to seed sourcing in restoration. While local provenancing is a common practice in restoration, local seeds may not survive or persist under future climate conditions. Alternative provenancing strategies, such as climate‐adjusted provenancing, that mix local seeds with non‐local seeds aim to increase the buffering capacity of restored populations. We hypothesized that seeds sourced from warmer and drier sites have higher seedling performance under drought than seeds sourced from cooler and wetter sites. We conducted a common garden experiment in a Great Basin rangeland where more frequent, severe drought events are expected to increase in the future. We sourced Bottlebrush squirreltail (Elymus elymoides [Raf.] Swezey) seeds from six locations along an aridity gradient and sowed them under three rainfall scenarios: ambient, moderate drought, and severe drought. We found strong interannual variation in seedling recruitment. In 1 year, some provenances from warmer/drier sites had high emergence and subsequent seedling survival under moderate drought. In another, emergence was low across provenances and rainfall treatments. Two provenances that survived 2 years of moderate drought had divergent seedling traits. Specifically, one had a high germination temperature optimum and high water‐use efficiency, such that it likely avoided freezing and resisted drought, while another had a low germination temperature optimum and low water‐use efficiency, such that it likely tolerated freezing and escaped drought. We highlight that understanding these differences in recruitment and stress coping strategies across provenances is important for creating climate‐adaptive seed mixes in anticipation of future climate conditions.