Further Examination of the Geographic Range of Eriogonum corymbosum var. nilesii (Polygonaceae, Eriogoneae)

The wild buckwheat Eriogonum corymbosum is widely distributed throughout the southwestern United States, forming a complex of eight varieties. E. corymbosum var. nilesii is a predominantly yellow-flowered variant reported primarily from Clark Co., Nevada. A previous genetic study by our research group found that var. nilesii is genetically distinct from other E. corymbosum varieties, based on a limited number of populations. Here, we assess genetic variation in 14 newly sampled yellow-flowered populations from southern Nevada, southern Utah, and northern Arizona, and compare them to genetic variation in six populations of previously determined E. corymbosum varieties. Of the new populations, we identified four as var. nilesii, four as var. aureum, three as var. glutinosum, two as apparent hybrids involving vars. aureum and nilesii, and one as a more distantly related admixture involving E. thompsoniae. Our results extend the range and area of E. corymbosum var. nilesii considerably from that traditionally stated in the literature. However, this extended range is confined to the Mojave Desert region of southern Nevada, and the number of known populations remains limited

Identifying Barriers to Successful Establishment of Post-Fire Seeding in the Great Basin

The shift of Great Basin ecosystems from diverse shrub-grass communities to near monocultures of annual grasses has altered ecosystems, caused more frequent and intense fires, and led to an increased demand for plant material that can restore altered landscapes back to complex, diverse systems. The Bureau of Land Management (BLM) in Nevada currently spends millions of dollars through the Emergency Stabilization and Rehabilitation (ES&R) program each year to re-seed land affected by fire. Seeds used for revegetation face many barriers that often prevent their successful establishment in this semi-arid environment including precipitation and temperature limitation, competition with invasive species, and soil type. Field surveys were done to monitor revegetation patterns between years and across aspects at five fire sites in Elko County, NV. A novel common garden experiment was conducted to determine what plants traits increase establishment success in invaded, post-fire field sites. We collected seeds from drill seeded populations of Elymus elymoides ssp. californicus (Toe Jam Creek bottlebrush squirreltail) at two fire locations in Elko County, NV. Seeds were planted in a common garden environment, where we compared the phenology, size, and reproduction of surviving plants to those of the original restoration material.In our field survey study, we found that vegetation structure within a site changed significantly in the short distance separating flat, north and south facing aspects; Bromus tectorum (cheatgrass) was more likely to establish on south aspects, residual grasses were more likely to remain on north aspects, and seeded perennial grasses were more likely to establish on flat areas. Over time, the density of B. tectorum and non-seeded perennial grasses and forbs increased, whereas the density of seeded perennial grasses and forbs decreased. We found that for both seeded and residual perennial grass, plant density in 2007 was a good predictor of the plant density in 2009. The density of B. tectorum in 2007 also predicted the density of B. tectorum in 2009, but not as strongly as perennial species. In our common garden experiment, plants grown from the original restoration material were larger, produced larger and more seeds, and produced seeds later in the season, while plants grown from material that successfully established at the restoration sites were smaller, produced smaller and fewer seeds, and produced them earlier. Differences in seed size were observed at the family level and persisted in the common garden environment through the next generation, indicating that seed size is likely a genetic, rather than maternal environment, effect. These results were consistent across two different field sites. Natural selection, rather than genetic drift, is the most likely explanation for trait shifts observed in established seed material, and these results indicate that smaller plants may be better adapted for establishment in arid environments. Our results suggest that altering current monitoring and seed production techniques may increase restoration success in the Great Basin. Modifying management objectives, seed mixes, and seeding efforts for slope-aspect and pre-fire site conditions may result in more cost effective and successful restoration. Restoration practices may also be improved if plant developers select for traits that perform well at restoration sites, rather than in controlled, production environments

Kulpa Leger Evol Apps Data

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Data from: Strong natural selection during plant restoration favors an unexpected suite of plant traits

Restoration is an opportunity to study natural selection: one can measure the distribution of traits in source propagules used to found populations, compare this with the distribution of traits in successful recruits, and determine the strength and direction of selection on potentially adaptive traits. We asked if natural selection influenced seedling establishment during post-fire restoration in the Great Basin, an area where large-scale restoration occurs with a few widely available cultivars planted over a large range of environmental conditions. We collected seeds from established plants of the perennial grass Elymus elymoides ssp. californicus (squirreltail) at two restoration sites, and compared the distribution of phenotypic traits of surviving plants with the original pool of restoration seeds. Seeds were planted in common gardens for two generations. Plants grown from seeds that established in the field were a non-random subset of the original seeds, with directional selection consistently favoring a correlated suite of traits in both field sites: small plant and seed size, and earlier flowering phenology. These results demonstrate that natural selection can affect restoration establishment in strong and predictable ways, and that adaptive traits in these sites were opposite of the current criteria used for selection of restoration material in this system

Similarity of Nutrient Uptake and Root Dimensions of Engelmann Spruce and Subalpine Fir at Two Contrasting Sites in Colorado

Nutrient uptake capacity is an important parameter in modeling nutrient uptake by plants. Researchers commonly assume that uptake capacity measured for a species can be used across sites. We tested this assumption by measuring the nutrient uptake capacity of intact roots of Engelmann spruce (Picea engelmanni Parry) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) at Loch Vale Watershed and Fraser Experimental Forest in the Rocky Mountains of central Colorado. Roots still attached to the tree were exposed to one of three concentrations of nutrient solutions for time periods ranging from 1 to 96h, and solutions were analyzed for ammonium, nitrate, calcium, magnesium, and potassium. Surprisingly, the two species were indistinguishable in nutrient uptake within site for all nutrients (P \u3e0.25), but uptake rates differed by site. In general, nutrient uptake was higher at Fraser (P =0.01, 0.15, 0.03, and 0.18 for NH4+, NO3−, Ca2+, and K+, respectively), which is west of the Continental Divide and has lower atmospheric deposition of N than Loch Vale. Mean uptake rates by site for ambient solution concentrations were , , , and at Loch Vale, and , , , and at Fraser. The importance of site conditions in determining uptake capacity should not be overlooked when parameterizing nutrient uptake models. We also characterized the root morphology of these two species and compared them to other tree species we have measured at various sites in the northeastern USA. Engelmann spruce and subalpine fir were indistinguishable in specific root length and diameter distribution, while most of the other 10 species had statistically distinct diameter distributions across five diameter classes

Who's Eating the Flowers of a Rare Western Nevada Range Plant?

The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform March 2020Legacy DOIs that must be preserved: 10.2458/azu_rangelands_v31i2_s._longlan

DataSheet_1_Field observations and remote assessment identify climate change, recreation, invasive species, and livestock as top threats to critically imperiled rare plants in Nevada.pdf

IntroductionRare plant species comprise >36.5% of the world’s flora and disproportionately support ecosystem function and resilience. However, rare species also lead global plant extinctions, and unique ecological characteristics can make them vulnerable to anthropogenic pressure. Despite their vulnerability, many rare plants receive less monitoring than is needed to inform conservation efforts due to limited capacity for field surveys.MethodsWe used field observations and geospatial data to summarize how 128 imperiled, rare vascular plant species in Nevada are affected by various threats. We assessed correlations between threats predicted by geospatial data and threats observed on the ground and asked how historic and current threats compare.ResultsThe most commonly observed threats were from recreation, invasive and non-native/alien species, and livestock farming and ranching. Threat prevalence varied by elevation (e.g., a greater variety of threats at lower elevations, greater threat from climate change observed at higher elevations) and land management. There was a 28.1% overall correlation between predicted and observed threats, which was stronger for some threats (e.g., development of housing and urban areas, livestock farming and ranching) than others. All species experienced extreme climatic differences during 1990-2020 compared to baseline conditions, with the most extreme change in southern Nevada. The average number of threats observed per occurrence increased by 0.024 each decade.DiscussionWhile geospatial data did not perfectly predict observed threats, many of these occurrences have not been visited in over 30 years, and correlations may be stronger than we were able to detect here. Our approach can be used to help guide proactive monitoring, conservation, and research efforts for vulnerable species. </p

Data from: Further Examination of the Geographic Range of Eriogonum corymbosum var. nilesii (Polygonaceae)

The buckwheat Eriogonum corymbosum is widely distributed throughout the southwestern United States, forming a complex of eight varieties. Eriogonum corymbosum var. nilesii is a primarily yellow-flowered taxon reported only from Clark County, Nevada. A previous genetic study by our research group found that variety nilesii is genetically distinct from other E. corymbosum varieties, based on a limited number of populations. Here, we assess genetic variation in 14 newly sampled yellow-flowered populations from southern Nevada, southern Utah, and northern Arizona, and compare them to genetic variation in six populations of previously determined E. corymbosum varieties. Of the new populations, we identified four as variety nilesii, four as variety aureum, three as variety glutinosum, two as apparent hybrids involving varieties aureum and nilesii, and one as a more distantly related admixture. Our results extend the range and area of E. corymbosum var. nilesii considerably. However, this extended range is confined to the Mojave Desert region of southern Nevada, and the number of known populations remains limited