Squirreltail Research Articles

Variation in the role of the flag‐leaf in reproductive effort of semiarid rangeland bunchgrasses

AbstractUnderstanding the mechanisms underlying viable seed production of perennial bunchgrasses is critical to improving restoration and conservation success in Great Basin sagebrush steppe rangelands. We studied the effects of pre‐ and post‐anthesis flag‐leaf removal and post‐anthesis seed‐head shading on reproductive effort in two important rangeland restoration species, the exotic crested wheatgrass (Agropyron cristatum) and native squirreltail (Elymus elymoides). Flag‐leaf removal had distinct, species‐specific effects on seed filling. Pre‐anthesis flag‐leaf removal in crested wheatgrass reduced the proportion of filled seeds, while post‐anthesis removal did not. In contrast, squirreltail increased filled seed proportions regardless of flag‐leaf removal timing. Neither flag‐leaf removal treatment affected seed quality, as quantified by seed‐specific mass (in grams per square meter), which significantly reduced with seed‐head shading in both species. Seed‐head shading reduced total propagule production (unfilled + filled seeds) in crested wheatgrass but increased it in squirreltail, possibly due to our shading method protecting from seed‐head herbivory or high‐light stress. Flag‐leaf removal in the squirreltail also induced a negative shading effect on filled seed area, mass, and specific mass. These findings suggest flag leaves can modulate reproductive effort outside of seed provisioning, either by maintaining pre‐fertilized seed viability, as in crested wheatgrass, or acting as a competitive sink to the fully emerged seed‐head, as in squirreltail. Moreover, this study demonstrates photosynthetic activity by the seed‐head itself is critical to the expression of seed quality traits important to seedling establishment success of semiarid perennial bunchgrasses.

Nontarget effects of herbicides on annual forbs and seeded grass in the Great Basin, United States, are partially offset by planting depth and application rate

Pre‐emergent herbicides can reduce the abundance of invasive annual plants, but they can also harm native plants, particularly annuals or perennial seedlings, including seeds planted during restoration. We assessed the effects of imazapic and indaziflam on invasive target and nontarget native plants in the Great Basin, a region with extensive invasive annual grasses. We tested nontarget effects on native annual forbs in an agricultural field previously used to grow native annual forbs, which contained a large seed bank. We seeded perennial grass (Elymus elymoides) at multiple depths to determine susceptibility and resistance. Herbicides were applied at full and reduced rates to mimic the effect of litter in natural systems. We observed reductions in most non‐native species in all treatments, but also extensive reductions of native annual forbs, although these were offset at lower application rates, and some species (e.g. Amsinckia tessellata and Microsteris gracilis) were less susceptible than others. Herbicides, particularly indaziflam, reduced E. elymoides emergence, but planting seeds at 2–3 cm depths improved emergence, particularly for imazapic, with 15–68% greater emergence than seeds planted at 1 cm. We suggest surveys for native annual forbs and resistant invaders before applying herbicides and field testing to determine whether reduced rates could provide weed control while maintaining annual forbs. We suggest planting E. elymoides at 2–3 cm when applying herbicides, an approach that may be effective for other species. Herbicide use can be an effective tool, but our results indicate that mitigation of nontarget effects will be needed to maintain native plant diversity.

Virtual Reciprocal Garden Assessment of Germination Syndromes for Elymus elymoides ssp. brevifolius and Elymus multisetus

Bottlebrush squirreltail (Elymus elymoides) and big squirreltail (Elymus multisetus) are high-priority species for restoration of millions of hectares of rangeland in the western United States that have been degraded by accelerated wildfire and introduced annual grasses. Previous research has compared potential germination and seedling performance of these species in a common environment and noted significant genetic differentiation in characteristics that are associated with their environments of origin. In this experiment, we used wet-thermal germination models and long-term simulations of seedbed microclimate to conduct a virtual reciprocal-garden analysis of the potential germination response of these species. We confirmed significant species differentiation in germination rate that appears to confer site-specific advantages for initial seedling establishment in their respective habitats of origin. Our results specifically highlight the relative importance of late-fall seeding for the more rapidly germinating E. multisetus in order to avoid early-fall germination and post-germination seedling mortality from freezing conditions in the winter. In contrast, the slower-germinating E. elymoides ssp. brevifolius A is less likely to germinate in the fall and likely avoids inherently harsher winter temperatures in the seedbed. Virtual simulations of this type might lead to identification of complex-trait genetic markers that are associated with intraspecific and interspecific adaptations to specific environments. Identification of these traits could also inform management of plant communities that are under threat from invasive weeds and climate change.

PSVI-27 Evaluation of Coated and Non-Coated Seed Species Pertinent to the Great Basin in Response to in Vitro Ruminal Incubation

Abstract Target grazing has exhibited itself as an effective method of invasive weed mitigation across degraded rangelands in the Great Basin. Additionally, if the seeds of target species are supplemented into the diets of ruminants, they can serve as vectors for the dispersal of native seed species through fecal pats, which may prove to be a useful tactic for rangeland rehabilitation. However, a challenge associated with seed supplementation, is that the seeds of many target species are sufficiently degraded in the rumen. Therefore, the aim of this study was to evaluate the effects of seed coating technologies on germination rates post ruminal in vitro incubation. In vitro incubations were performed on seven species of seeds pertinent to the Great Basin: Achnatherum hymenoides (ACHY), Achillea millefolium (ACMI), Agropyron cristatum (AGCR), Atriplex canascens (ATCA), Elymus elymoides (ELEL), Pseudoregneria spicata (PSSP), and Sphaeralcea grossulariifolia (SPRT) uncoated (control) or coated with either Polyvinylpyrrolidone (PVP) or PVP+ ethocel, as well as uncoated Bromus tectorum (BRTE) seeds. A Daisy II incubator (Ankom Technology, Macedon, NY) was used for the in vitro analysis with rumen inoculum from two rumen-cannulated crossbred Angus steers (body weight = 910.5 ± 34.5 kg) and a buffer ratio of 1:4. Two F57 filter bags containing 1 g of seeds per treatment (control, PVP or PVP+ethocel) were then placed inside of the Daisy II incubator and kept at 39°C for 12 and 24 h for the control treatments, and for 12, 24, and 48 h for the PVP and PVP+ethocel coating treatments. For uncoated seeds, ACHY germination by 24 h was greater when compared with 0 h (P < 0.05), whereas ATCA germination rate decreased linearly by 12 h (P < 0.05). No differences were observed over time on germination rates of BRTE, as well as all of the other uncoated seeds (P > 0.05). When seeds were coated with PVP, ATCA germination rates started to linearly decrease by 12 h (P < 0.05), whereas PVP coated ACMI germination rates only started to decrease by 24 h (P < 0.05). The germination rates of PVP coated ELEL and PSSP seeds only started to significantly decrease by 48 h (P < 0.05). When coated with PVP+ethocel, the observed germination rates were similar to those observed for PVP coated seeds. However, when compared with uncoated seeds, coating with PVP+ethocel seem to decrease germination rates of ACMI and ATCA by 0 h (P < 0.05). No changes on germination rates were observed over time for coated and uncoated AGCR and SPRT (P > 0.05). In conclusion, seed germination rates after in vitro incubation were not increased by coating the seeds with PVP or PVP+ethocel.

353 Evaluation of Native and Invasive Seed Germination Ability After in Situ Incubation in the Rumen for Rangeland Restoration Through Targeted Seed Supplementation

Abstract Changes to native plant compositions of drylands are often associated to loss of wildlife, increased frequency, and severity of wildfires; further, it complicates the grazing permits and allocation during periods of restoration. The goals herein investigate the germination rates of native seed species after in situ incubation to evaluate their potential dispersal as supplements for grazing cattle. Native: Indian ricegrass (Achnatherum hymenoides; ACHY), white yarrow (Achillea millefolium; ACMI), crested wheatgrass (Agropyron cristatum; AGCR), sagebrush (Artemisia tridentata; ARTR), fourwing saltbrush (Atriplex canascens; ATCA), bottlebrush squirreltail (Elymus elimoides; ELEL), bluebunch wheatgrass (Pseudoregneria spicata; PSSP), and gooseberryleaf globemallow (Sphaeralcea grossulariifolia; SPRT) and nonnative: cheatgrass (Bromus tecorum, BRTE; fall BRTEf and spring seeds BRTEs) seeds were examined. Four ruminally canulated Angus x Hereford steers adapted to a forage kochia-alfalfa diet were utilized for seed incubations. Seeds were weighed into 84 bags at a rate of 5 g per bag (duplicated within and in different animals). Seeds were incubated sequentially (0, 6, 12, 24, 36, 48, and 96 h) and removed at the 96-h point when seeds were thoroughly washed and immediately counted (50) on square 80 mm 80 mm commercial sterile petri dishes with moisture pads and 5 mL of water. Seeds were incubated at 20 °C with 12 h of light/no-light intervals. Germination plates were incubated for 50 d and counted every 10 d for germinations. Generalized linear models assuming a Poisson distribution with separation of means through Dunnett’s multiple comparisons test. Statistical significance was declared at P < 0.05. All statistical analyses were performed on R (R Core Team 2022). Incubation times inside of the rumen linearly decreased germination rates across most seed species. For BRTEs, germination completely stopped at 48 h with a steep decrease observed after 24 h incubation. The BRTEf were also incubated but showed low germination both before and after rumen exposure (winter dormancy). Though ARTR is very important in rangeland restoration in the intermountain west, its germination declined more than 85% within just a 6 h incubation in situ (P < 0.001). A significant germination decrease was observed for AGCR at 36 h; however, germination was full at 48 h and 50% of the original at 96 h (P < 0.05). For ACMI, germination rates significantly declined after 36 h incubation, and for PSSP after 24 h. Low germinations were observed for ACHY, SPRT, and ATCA even with high reported in-bag tetrazolium chloride viabilities. Our results highlight that cattle grazing of cheatgrass does not spread seeds through fecal pats. Additional tests are required to determine seed viability of the dormant (low germination) BRTEf. Seed toleration to ruminal degradation highlights the potential targeted seed supplementation during grazing for rangeland restoration.

Under drought conditions, fungicide seed coating does not increase emergence of two native grass species in sagebrush stands of the Intermountain West, U.S.A.

Coating seeds with amendments to increase germination, emergence, and establishment is a promising strategy for dryland restoration. Seed coatings containing fungicides offer a potential solution in regions where fungal pathogens cause seed mortality during the winter stratification period between late fall seeding and spring germination. The effectiveness of the fungicide treatment, however, may be dictated by weather and within‐site microenvironment. We tested how fungicide coating influenced seedling emergence of native grasses within sagebrush stands by planting untreated seeds and seeds coated (encrusted) with and without active fungicide ingredients in furrows that extended from the canopy edge of sagebrush plants (Artemisia tridentata ssp. wyomingensis) into the interspace. This was replicated at four sites across the Intermountain West in two successive years. We planted two native grasses, bottlebrush squirreltail (Elymus elymoides) and bluebunch wheatgrass (Pseudoroegneria spicata). Emergence was extremely low in both years, with a complete seeding failure (i.e. zero emergence) at two sites in the first year and three sites in the second year. At one site where emergence was sufficient for statistical analysis: (1) the coating on the fungicide and blank treatments inhibited emergence under anomalously dry conditions and (2) across seed treatments, proximity to a sagebrush canopy slightly increased seedling emergence. The variable emergence patterns across sites and years (i.e. the highest emergence was for the site–year combination with the lowest precipitation) highlight the sensitivity of seeding outcomes to, and dependence of fungicide seed coatings on, site conditions, and the necessity of repeating experiments across different weather years.

Goldilocks forbs: survival is highest outside—but not too far outside—of Wyoming big sagebrush canopies

In arid and semiarid systems, positive effects of nurse shrubs generally occur immediately underneath and around shrub canopies, creating microsites that can be targeted to promote plant establishment in restoration settings. Alternatively, the best microsites may occur in the interspace zone immediately surrounding nurse shrubs if positive abiotic effects extend beyond nurse shrub canopy boundaries and if competition with nurse shrubs is reduced in that zone. In the Intermountain West, U.S.A., we investigated survival of transplanted herbaceous seedlings at different distances from Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) canopies. We planted two native perennial forb species, Munro's globemallow (Sphaeralcea munroana) and common yarrow (Achillea millefolium), and two native perennial grass species, bluebunch wheatgrass (Pseudoroegneria spicata) and bottlebrush squirreltail (Elymus elymoides), at four distances from sagebrush canopies at six sites across the Intermountain West, repeated across 2 years. Under above‐normal precipitation, proximity to sagebrush influenced first‐year survival of the forb, but not grass, species. Globemallow and yarrow survival were highest mid‐way between the canopy dripline and maximum interspace distance between neighboring sagebrush plants. Ground cover characteristics and globemallow survival covaried with respect to distance from shrub, suggesting ground cover characteristics as indicators of suitable planting microsites. Under drier conditions, survival of all species was low and unaffected by distance from canopies. Our results demonstrate the value of fine‐tuning the canopy‐interspace paradigm to more carefully consider how plant performance may differ across zones within the interspace region between plants, especially when the goal is to maximize plant establishment in nondrought years.

Superabsorbent Polymer Use in Rangeland Restoration: Glasshouse Trials

Post-disturbance rangeland restoration efforts are often thwarted due to soil moisture deficits. Superabsorbent polymers (SAPs) absorb hundreds of times their weight in water, increasing soil moisture when the SAP is mixed with soil. The objective of this study was to evaluate banded SAPs under the soil surface to increase plant available water and thus seedling establishment for perennial rangeland species during restoration efforts. Five glasshouse experiments with two rangeland perennial grass species, bottlebrush squirreltail (Elymus elymoides) or Siberian wheatgrass (Agropyron fragile), were conducted. Treatments varied, including SAP rates ranging from 11–3000 kg ha−1 with placement mostly banded at depths extending from the surface up to a 15 cm depth. Generally, SAPs increased soil moisture at all rates and depths for up to 49 days. However, rates ≥ 750 kg ha−1 caused the soil to swell and crack, potentially hastening soil drying later in the season. Seedling longevity was increased up to 12 days, especially at the high SAP band rate of 3000 kg ha−1 when the band was 8 or 15 cm deep. Further work is needed to verify banded SAP rates and placement depths in the field, ascertain conditions to reduce soil displacement, and evaluate benefits across species.

Synergistic effects of biochar and arbuscular mycorrhizal fungi on enhancing Elymus elymoides growth in saline coastal soil

Synergistic effects of biochar and arbuscular mycorrhizal fungi on enhancing Elymus elymoides growth in saline coastal soil

The Ability of Selected Plants to Absorbing CO₂, CO and HC from Gasoline Engine Exhaust

Global warming is the unusually rapid increase in the earth’s average surface temperature, which has an impact on climate change. The cause of global warming is the inhibition of heat transfer from the earth’s surface to space, which is analogous to the greenhouse effect. The occurrence of the greenhouse effect is due to the large amount of carbon dioxide (CO2) produced by the complete combustion of fuel in vehicles and industrial processes. The rising use of fossil fuels and the ongoing reduction in forest plants’ ability to absorb CO2 is to blame for the rise in CO2 levels in the atmosphere. To reduce the increase in CO2 gas, one effort that can be made is to increase CO2-absorbing plants. In this regard, plants are able to absorb CO2 and convert it into oxygen and glucose by utilizing solar heat. The purpose of this study is to determine the ability to absorb CO2 from several types of plants. The test was carried out using two closed test rooms with dimensions of 100×50×50 cm, where room 1 (first) was used to store 0.5% of CO2 emissions, while room 2 (second) was used for the plants being tested. Gas is flowed into room 2 using a fan for 300 minutes, and data collection is carried out every 60 minutes. Based on results obtained in this line of research, the best plant ability to absorb CO2 can be ordered as follows 0.25 mg/m2.hour for squirrel tail, 0.243 mg/m2.hour for trembesi, 0.2 mg/m2.hour for mahogany, 0.177 mg/m2.hour for kaffir lime, 0.166 mg/m2.hour for mango, and 0.166 mg/m2.hour for cape.

Monitoring Seedling Emergence, Growth, and Survival Using Repeat High-Resolution Imagery

Environmental factors often limit plant establishment and survival through increased seedling mortality. Understanding plant growth and the causes of mortality can be helpful in developing solutions that enhance seeding success and improve restoration monitoring. The purpose of our research was to assess the efficacy of time lapse and motion sensing cameras for monitoring seedling height, density, and fate. We conducted this study in a salt desert shrub community in northwest Utah, USA. In spring 2017, we placed 28 cameras in fenced and unfenced plots seeded with bottlebrush squirreltail and collected hourly images of the seedlings’ development for the initial four months post-seeding. The seedling attributes were recorded in-field and compared with camera images to determine accuracy and reliability. We found that the optimal period for capturing imagery occurred near the sun’s zenith when shadows were minimized. We were able to detect both the timing of the plant emergence, plant height, density, growth rate, and seedling death. The average seedling height and density were underestimated by 14% and 30% between the camera and field estimates, respectively. We recognize that it could be beneficial to adjust for the effect of the date. The reduced seedling density improved the measurement accuracy through a lower visual obscurity. Managers can utilize remote cameras to effectively measure vegetation that can provide an insight into environmental influences.

KAJIAN KARAKTERISTIK ABNORMALITAS TANAMAN KELAPA SAWIT (Oil Palms)

Oil palm is the largest vegetable oil-producing plantation crop in the world. The need for oil palm seeds increases along with the increasing demand for oil palm products. The need for these seeds needs to be balanced with the presence of ordinary oil palm seeds. The abnormalities in oil palm plantations were found due to the selection of seeds that were less selective. Chimera in plants is the formation of characteristics that are governed by several genotypic constitutions and grow side by side with each other in tissues. In oil palm, chimeras can begin to appear in the seedling phase. The characteristics of abnormalities can be seen in terms of morphology and plant physiology. Based on morphological characteristics, chimera plants have a phenotype that is determined by the presence of white or bright yellow leaves parallel to the stem, stunted plants, rosettes, undeveloped leaves, mantle sissy flowers, followed by squirrel tail flowers (androgynous), thick coat fruits, and thin skin. . Based on physiological characteristics, chimeras occur due to changes in chloroplast development which result in changes in the chlorophyll content of oil palm plants. Oil palm plants that are considered abnormal from time to time can turn into normal plants depending on the level of abnormality of each plant. This study aims to examine the characteristics of abnormalities in oil palm plants. Therefore, it can be seen that oil palm seeds are classified as abnormal to be selected before planting in the field. This is done to obtain high potential oil palm plantations. Keywords : chimera, morphology, physiology, phenotype, genotype

Management and environmental factors associated with simulated restoration seeding barriers in sagebrush steppe

Adverse weather conditions, particularly freezing or drought, are often associated with poor seedling establishment following restoration seeding in drylands like the Great Basin sagebrush steppe (U.S.A.). Management decisions such as planting date or seed source could improve restoration outcomes by reducing seedling exposure to weather barriers. We simulated the effects of management and environmental factors on seedling exposure to post‐germination barriers for bottlebrush squirreltail (Elymus elymoides), Sandberg bluegrass (Poa secunda), and bluebunch wheatgrass (Pseudoroegneria spicata). We combined germination timing models with daily soil moisture and temperature estimates to calculate yearly germination favorability and post‐germination freezing and drought barriers for three planting dates (15 October, 15 November, and 15 March) and three seed sources or cultivars per species for 5,000 sites in each of 40 years (water years 1980–2019). We tested the effects of site environmental variables (elevation, mean annual precipitation, heat load, and clay content) and management choices (seed source and planting date) on germination favorability and barrier occurrence (mean) and variability (coefficient of variation). Seedling exposure to barriers was strongly linked to management decisions in addition to site mean precipitation and elevation. Later fall plantings and seed sources with slower germination (lower mean germination favorability) were less likely to encounter freezing and drought barriers. These results suggest that management actions can play a role comparable to site environmental variables in reducing exposure of vulnerable seedlings to adverse weather conditions and subsequent effects on restoration outcomes.

Water as the key to sagebrush restoration success in cheatgrass‐invaded ecosystems

Restoration treatments in Bromus tectorum (cheatgrass)‐invaded sagebrush habitat have often produced poor results. This is perhaps due to multifaceted ecological changes associated with cheatgrass invasion like reduced water availability, altered nutrient availability, and shifts in soil microbial communities. We tested whether suppressing cheatgrass, altering nutrient availability, and inoculating with soil microbes improved restoration success. We conducted field experiments in Idaho, Utah, and Arizona where we transplanted seedlings of Artemisia tridentata ssp. tridentata (basin big sagebrush) and Elymus elymoides (squirreltail). Growth and survivorship of both species were higher in sites with greater precipitation and lower cheatgrass abundance. Significant nutrient modification effects were seen in Utah, where cheatgrass abundance was highest and soil nutrients were most limiting. In Utah, we observed an increase of 14% in survivorship for squirreltail in response to carbon addition, and 119% increase in growth of sagebrush with phosphorus addition. Inoculating plants with sagebrush rhizosphere soil or a commercial arbuscular mycorrhiza at the time of planting did not significantly affect growth, survivorship, arbuscular mycorrhizal fungi colonization, or extraradical mycorrhizal hyphae length for either plant species. The largest effects on seedling growth (+384%) and survivorship (+262%) were observed in response to the suppression of cheatgrass using a weed barrier cloth and associated with increased water availability. Interactions between suppressing cheatgrass, altering nutrient availability, and inoculating with soil microbes were not significant. Direct reduction of cheatgrass was shown to be more effective than targeting soil legacy effects associated with cheatgrass with regards to restoration outplanting success.

Plant growth and biocrust-fire interactions across five North American deserts

Biological soil crusts (biocrusts) are communities predominately comprised of lichens, bryophytes, fungi, algae, and cyanobacteria that form at the soil surface in dryland ecosystems worldwide. Biocrusts can influence the vascular plant community by altering surface hydrology, nutrient cycling, and the availability of microsites suitable for germination. Fire frequency has increased in many dryland systems, but the potential impacts of fire on biocrust-plant interactions remains unclear. Our study explores how biocrusts and the heating associated with fire affect plant growth across five North American desert sites: the Chihuahuan, Colorado Plateau, Great Basin, Mojave, and Sonoran. Using field-collected biocrusts and mineral soil samples from each of these five deserts, we investigated soil biogeochemical differences and the implications of soil heating and biocrust cover on greenhouse grown Elymus elymoides plants. Results showed plant biomass and leaf production were largely determined by the desert where soils originated, and that the soils collected from the Great Basin site, whether heated or not, were generally higher in nutrients and distinct from the other North American desert sites. In contrast, the Chihuahuan site was lower in nutrients and plant biomass growth compared with the other desert sites. In the short term, biocrusts and heating did not significantly affect the biogeochemical profile of individual desert site soils. However, biocrusts and soil heating positively influenced plant growth, and the combination of these factors influenced plants more strongly than either factor considered separately. These findings highlight the importance of biocrusts in mediating resources and suggest additional mechanisms through which fire may alter or accentuate dynamics between biocrusts and vascular plants.

Leveraging Historic Cattle Exclosures to Detect Evidence of State Change in an Arid Rangeland

Grazing, a defining use of rangelands, can have immediate and legacy impacts in ecosystems with short evolutionary histories of grazing and where climatic conditions are marginal and variable. In arid rangelands of the Colorado Plateau, domesticated ungulates were introduced in the 1800s at high densities and grazing has been maintained in the region at variable stocking rates for approximately the past 150 yr. Historic grazing practices, combined with a marginal climate, may have caused an irreversible shift in the vegetation community leading to limited recovery with cessation of grazing. Using three exclosures ranging from 12 to 50 yr of age, we evaluated vegetation composition, diversity, and cover inside the exclosures and compared them with directly adjacent, actively grazed areas outside of the exclosures in the fall and spring of 2018 and 2019. We then asked 1) How do exclosures and their adjacent unexclosed sites differ in vegetation diversity, composition, and cover? and 2) Are there significant differences in cover of key forage species in exclosed versus unexclosed areas? Overall, there were significant differences in vegetation communities inside and outside of exclosures in both seasons. Composition, alpha, and beta diversity differed between grazed and exclosed sites, with higher alpha and beta diversity in the 50-yr exclosure in the fall. Composition was significantly different between exclosures and unexclosed sites at all sites and in all seasons. Cover of several important forage grasses (Achnatherum hymenoides, Hilaria jamesii, Elymus elymoides) was higher in exclosed areas, while cover of Scleropogon brevifolius and Bouteloua gracilis was higher in unexclosed areas. Taken together, these results indicate limited recovery of vegetation in the absence of grazing, with exclosures exhibiting higher plant diversity, as well as cover of some desirable forage species, suggesting this area has not undergone irreversible state change but recovery may require > 50 yr of grazing cessation.

Slope and Aspect Effects on Seedbed Microclimate and Germination Timing of Fall-Planted Seeds

Rangeland vegetation in the Great Basin, United States, is frequently disturbed by natural- and human-caused wildfires that facilitate the establishment and dominance of introduced annual weeds such as cheatgrass (Bromus tectorum) and medusahead wildrye (Taeniatherum caput-medusae [L.] Nevski). Ecological resilience and resistance of native and seeded-non-native plant communities in this region, however, appear to follow topographic patterns associated with slope, aspect, and elevation. Currently, resistance and resilience concepts are being used to prioritize rangeland restoration efforts based on soil-climate classification. We hypothesized that probabilistic patterns of shorter-term weather effects on seedbed microclimate might also be correlated with these perceived spatial patterns of resistance and resilience over space. We used a 39-yr gridded weather dataset to estimate seedbed temperature and water potential at seeding depth as a function of slope and aspect using the Simultaneous Heat and Water (SHAW) model. Seedbed temperature and water potential were then used as input to hydrothermal germination response models to generate indices of seedbed favorability for initial germination and emergence and to estimate cumulative germination response as a function of topography and planting date for the very-fast-germinating cheatgrass, fast-germinating bottlebrush squirreltail (Elymus elymoides [Raf] Swezey), and slower-germinating Idaho fescue (Festuca idahoensis Elmer). Topographic mapping of seedbed favorability showed distinct seasonal patterns associated with both slope and aspect. Southern exposures are likely to facilitate both prewinter germination for early-fall-planted seeds and relatively more midwinter germination for seeds planted later in the fall, but these exposures are also less subject to midwinter frost effects. Northern exposures were likely to delay germination into later winter and early spring and thus avoid potential exposure to a higher probability of winter frost mortality. Microclimatic simulations of this type may provide new metrics for improving our understanding of the mechanistic causes of observed patterns of ecological resistance and resilience over space.

An assessment of seed head and flag leaf contributions to reproductive effort in sagebrush steppe bunchgrasses

North American sagebrush-steppe bunchgrasses primarily establish from seed; however, the importance of parental plant carbon from flag leaves or within the seed head itself to reproduction in perennial bunchgrasses is unknown. To address this, we experimentally removed flag leaves and shaded seed heads to assess their importance to reproduction in the exotic bunchgrass crested wheatgrass (Agropyron cristatum), which has high seed head photosynthetic capacity and readily establishes from seed, and the native grass, squirreltail (Elymus elymoides), which has lower seed head photosysnthetic capacity and does not establish as readily from seed. We hypothesized that inflorescence shading would have a greater negative impact on crested wheatgrass reproduction than in squirreltail. In crested wheatgrass, shading did not affect total propagule production but did reduce both total filled seeds and filled seed specific mass (dry mass per unit area). Flag leaf removal stimulated seed filling and increased seed specific mass, especially in unshaded seed heads, suggesting flag leaves are competitive carbon sinks in crested wheatgrass. In contrast, flag leaf removal and shading in squirreltail resulted in similar reductions in total propagules, fewer filled seed produced and lower specific seed mass, indicating similar contributions to reproductive effort by both structures. These results indicate seed head photosynthetic activity is an adaptive reproductive feature in both grasses, but the contrasting effects of flag leaf removal may reflect long-term adaptive responses to grazing pressures that differed in crested wheatgrass's native range compared to those in North American sagebrush steppe.

Play it Safe

Play it Safe Michelle Ross Jessie once drove through a hurricane because, stupidly, she'd thought the eye of the storm was far enough away that returning to her apartment in Tallahassee—she'd been staying with a friend four hours away in Atlanta—was safe. By the time she realized her mistake, it was one in the morning, and turning back with no place to stay—her two cats were in the car with her, screeching all the way—seemed even more precarious than continuing. Driving to her daughter's school carnival, where she'd have to socialize with the parents of Ellen's schoolmates in the service of raising funds for new playground equipment, felt kind of like that drive through heavy rain and wind and felled trees and the impending threat of more falling trees. She couldn't relate to these people. Take Ava's mom, for instance. Sharon was the PTA committee member in charge of organizing this carnival. The woman ended every email with "Smiles, Sharon." Jessie puzzled over this letter closing for longer than Gabe thought warranted. "You overthink everything," he said from the passenger seat. He was drinking a vodka tonic—out of a regular drinking glass, too, not even trying to conceal that he had an open container of alcohol. "I'm not the one driving," he said when she eyed his drink. Then he said she was just jealous and not to worry, he'd brought a flask and a small bottle of tonic water and she could have a drink in the parking lot when they got there. Their eight-year-old daughter, Ellen, had her headphones on in the backseat. She was watching a cartoon in which the main characters changed size and donned various techy animal suits. In a Sonoran desert episode, one of the few episodes Jessie had watched with Ellen, the men transformed themselves into faux rattlesnakes and then observed a real, albeit cartoon, rattlesnake go after a squirrel. Cornered, the squirrel pumped extra blood to its tail and shook the tail so that in the snake's infrared heat vision, the squirrel's tail appeared to inflate like a balloon, fooling the snake into striking at the tail rather than the vital organs. Jessie had cheered when the snake missed and the squirrel escaped. Ellen had said, "Yeah, but maybe the squirrel living means the snake starves to death." That was Ellen for you. Her capacity for empathy extended even to venomous predators. What was different about the dread Jessie felt for this particular school event versus school events of the past was that three days ago she'd been attacked while out running. She'd been running along a residential [End Page 59] street, not a remote location, such as the trails in Saguaro National Park East, where she was always scanning the desert scrub for rattlesnakes and mountain lions. It hadn't even happened particularly early in the morning. The sun had already started to peak over the Rincon Mountains. When she heard footfalls and turned, even though the man was dressed in jeans and was looking right at her, still her brain reasoned he must have a good reason for seeming to lunge towards her that she had simply failed to decipher. She thought he must be trying to protect her from something. A mountain lion perhaps? Though rare, mountain lion sightings did occasionally occur in town. Or maybe he was running from a mountain lion; he needed her help. But then he crashed into her and one hand went directly to her breast, the other over her mouth, and she understood that this man was the mountain lion she'd imagined. She'd fought him off and other than a few cuts and bruises, and the memory of his hands, she was fine really. But in her post-attack shock, adrenaline high, she'd allowed herself to be interviewed by a local reporter, who'd arrived nearly as soon as the police, and almost an hour before Gabe. He'd inadvertently left his damn cellphone in silent mode again. The only sentence from Jessie's mouth that had not been too...

Selecting native plants for restoration using rapid screening for adaptive traits: methods and outcomes in a Great Basin case study

Partnerships between researchers and restoration practitioners can improve restoration outcomes, which is especially important for restoration in challenging settings. Here, we describe one such partnership in the Great Basin, United States, which used trait‐based methods and practitioner knowledge to identify the most promising seed sources for restoration. Managers in this region can either use widely available commercial seeds, which are often sourced from far outside the seeding area, or take extra steps to use locally collected seeds. We asked whether local, wild‐collected seeds of two native plants, Elymus elymoides and Poa secunda, had traits more conducive to seedling establishment in degraded sites, relative to commercial sources. Seeds were collected from four remnant native populations within lands managed by the Winnemucca Bureau of Land Management. Collections were screened for seed and seedling characteristics previously identified as associated with increased seedling performance in degraded Great Basin systems, and we provide a detailed methodology for these measurements. Relative to commercial seeds, wild‐collected seeds had more characteristics identified as beneficial for seedling establishment, including phenology, root allocation, root form, and overall size characteristics that suggest locally sourced populations would be likely to establish better than commercial sources. Using phenotypic traits as criteria, the most promising wild populations were selected for agronomic production to increase the quantities of seeds available for restoration, and field trials are ongoing using these field‐increased seeds. These results provide support for collaborative efforts to identify, collect, screen, and increase the availability of local seed sources to improve restoration success.