Drought and leaf herbivory influence floral volatiles and pollinator attraction. Global Change Biology. 22: 1644-1654. website. Components of climate change have the potential to strongly influence floral volatile organic compounds (VOCs) and, in turn, plantpollinator interactions. In this study, we experimentally manipulated drought and herbivory for four forb species to determine effects of these treatments and their interactions on (1) visual plant traits traditionally associated with pollinator attraction, (2) floral VOCs, and (3) the visitation rates and community composition of pollinators. Experimental drought universally reduced flower size and floral display, but there were species-specific effects of drought on volatile emissions per flower, the composition of compounds produced, and subsequent pollinator visitation rates. The community of pollinating visitors was influenced by drought across forb species. These results indicate that VOCs may provide more nuanced information to potential floral visitors and may be relatively more important than visual traits for pollinator attraction, particularly under shifting environmental conditions.
Cheatgrass die-offs as an opportunity for restoration in the Great Basin, USA: Will local or commercial native plants succeed where exotic invaders fail? Journal of Arid Environments. 124: 193-204. website Bromus tectorum (cheatgrass) has widely invaded the Great Basin, U.S.A. The sporadic natural phenomenon of complete stand failure (‘die-off”) of this invader may present opportunities to restore native plants. Evaluating a recent die-off in Nevada, scientists found that although emergence and growth of native seeds was lower in die-off than control plots early in year one, in year two, seedlings in die-offs had increased vigor and growth, at equal or higher densities, than control plots. Local seeds consistently outperformed nonlocal seeds for P. secunda, whereas for E. elymoides, nonlocal showed an advantage in the first season, but in the second season, there were more local seeds present under die-off and unraked conditions. Our results warrant further investigation into die-off restoration as well as recognition of the importance of seed source selection in restoration.
RMRS-GTR-348, Conservation and Restoration of Sagebrush Ecosystems and Sage-Grouse: An Assessment of USDA Forest Service Science. The GTR is available at website. Forest Service science has helped to meet continuing widespread concerns and calls for science-based conservation to mitigate threats to sagebrush ecosystems, conserve populations of sage-grouse and other sagebrush obligate species, and restore sagebrush ecosystems throughout the western United States. The team prepared this assessment to summarize Agency strengths, capabilities, partners, past and current research, and potential future priority research areas for conservation and restoration of sagebrush ecosystems and sage-grouse. We identified four areas of strength, leadership, and knowledge development: 1) Evaluating sage-grouse population ecology, monitoring, and habitat linkages; 2) Understanding disturbances and stressors in sagebrush ecosystems; 3) Analyzing and designing
Male greater sage-grouse detectability on leks. Journal of Wildlife Management. 80(2): 266-274. website. Understanding factors that influence detection probabilities will allow managers to more accurately estimate the number of males present on leks. We fitted 410 males with global positioning system and very high frequency transmitters, and uniquely identifiable legbands over 4 years in Carbon County, Wyoming. We counted male sage-grouse using commonly used lekcount protocols and evaluated variables associated with our ability to detect marked males using sightability surveys on 22 leks. Detection probabilities were generally high (x=87) but varied among leks from 0.77 to 0.93. Male sage-grouse detection declined with increasing sagebrush height and bare ground and increased with more snow cover. Sightability models predicted detection well and can be used to accurately estimate male abundance on leks from lek counts, which is especially useful where accurate abundance estimates are required or inference about population status is based on only 1 count.
Influence of mountain pine beetle epidemic on winter habitat conditions for Merriam’s turkeys: Management implications for current and future condition. Proceedings of the National Wild Turkey Symposium. 11: 79-87. website. Scientists quantified habitat changes over time for turkeys following a widespread mountain pine beetle epidemic in the Black Hills of South Dakota and evaluated how many years it will take for optimal winter habitat conditions within ponderosa pine forests to recover following such a disturbance. Our Habitat Suitability Index indicated winter habitat quality decreased following the MPB outbreak due to conversion of ponderosa pine >40% canopy cover and trees >22.9-cm diameter at breast height (DBH) to smaller diameter (2.54cm to 22.9-cm DBH) structural stages. Simulations indicated that time for stands to return to optimal winter habitat conditions after the pine beetle outbreak varied depending on forest structural stage of residual trees and management action.
Rangeland drought: Effects, restoration, and adaptation [Chap. 8]. In Effects of drought on forests and rangelands in the United States: A comprehensive science synthesis. Gen. Tech. Rep. WO-93b. Washington, DC: USDA Forest Service, p. 155-194.website Drought can have severe impacts on rangeland ecosystems in North America. Drought impacts vary depending on the severity, frequency, duration, and aerial extent of the drought(s); how the land is managed; and whether plans are in place and implemented to respond to drought. Drought can be simply defined as “a lack of water” characteristic of time, not of place; or it can be defined in a climatic context, as “precipitation levels that are much lower than the annual average”. Four drought classifications are considered: (1) meteorological drought which focuses on water in the atmosphere, (2) hydrologic drought which focuses on available surface water, (3) agricultural or soil moisture drought which emphasizes crop response to declining moisture in soils, and (4) socioeconomic drought which emphasizes the social and economic impacts of drought.
RMRS-GTR-347, Foundational Literature for Moving Native Plant Materials in Changing Climates.website. Land managers use seed transfer guidelines to manage the movement of plant materials, but by the end of the century, many landscapes across the globe will have climates that are incompatible with current vegetation. The mismatch in rates between climate change and plant migration and adaptation will pose significant challenges for managers, especially when scientific information often lags behind the demand for management actions. Therefore, research plant physiologists Kas Dumroese and Jeremy Pinto and colleagues developed a bibliography, “Foundational Literature for Moving Native Plant Materials in Changing Climates,” to reflect the growing interest in assisted migration, the intentional movement of plant materials in response to climate change.
Seedling establishment and physiological responses to temporal and spatial soil moisture changes. New Forests. 47(2): 223-241. website. In many forests of the world, the summer season (temporal element) brings drought conditions causing low soil moisture in the upper soil profile (spatial element) – a potentially large barrier to seedling establishment. We evaluated the relationship between initial seedling root depth, temporal and spatial changes in soil moisture during drought after outplanting, and subsequent seedling performance using seedlings of Pinus ponderosa Laws. var. ponderosa grown in three containers similar in dimension except for depth (i.e. three stocktypes). Soil moisture patterns were quantified and growth, gas exchange, and carbon isotope analysis were used as metrics for stocktype evaluation.
Can biochar be used as a seed coating to improve native plant germination and growth in arid conditions? Journal of Arid Environments. 125: 8-15. websiteSeed coating technologies that use biochar may have the potential to overcome moisture and temperature limitations on native plant germination and growth. Biochar is a popular agronomic tool for improving soil properties, such as water availability and nutrient retention and has been recently marketed, but not tested, as a seed coating. We analyzed the effect of biochar seed coating thicknesses on the germination and growth of four plant species native to western United States. Our results, alongside the high economic expense of native plant seed and direct seeding operations, suggest that biochar, by itself, may not be an appropriate seed coating for improving native plant establishment.