Socio-Ecological Interactions Promote Outbreaks of a Harmful Invasive Plant in an Urban Landscape

Urban landscapes often harbour organisms that harm people and threaten native biodiversity. These landscapes are characterized by differences in socioeconomic context, habitat suitability and patch connectedness. Identifying which spatial differences enable outbreaks of pests, pathogens and invasive species will improve targeted control efforts. We tested hypotheses to explain the distribution and demography of puncturevine Tribulus terrestris, a human-dispersed invasive plant in Boise, a city in the western United States. We hypothesized an increase in puncturevine infestations near low-valued properties with a high proportion of bare ground, the species\u27 preferred microhabitat, that are well connected on the urban road network. To test these hypotheses, we collected data on the abundance, emergence and persistence of reproductive plants in transects spanning \u3e100 km of our study city. We then used hierarchical Bayesian models to evaluate the impacts of spatial covariates on puncturevine distribution and demography. Bare ground cover consistently increased abundance, emergence and persistence of puncturevine, indicating the overarching importance of suitable establishment sites for this invasive species. Property value had the strongest impact on puncturevine abundance and was the most important main effect in the model for puncturevine emergence. In both models, lower-valued properties had a higher risk of puncturevine occurrence. The effects of road network connectivity depended on bare ground cover, with the highest predicted abundance and emergence of puncturevine in patches with low connectivity on the road network and high bare ground cover. Understanding these relationships will require data that can disentangle seed dispersal from establishment limitations

Big Sagebrush (Artemisia tridentata) in a Shifting Climate Context: Assessment of Seedling Responses to Climate

The loss of big sagebrush (Artemisia tridentata) throughout the Great Basin Desert has motivated efforts to restore it because of fire and other disturbance effects on sagebrush-dependent wildlife and ecosystem function. Initial establishment is the first challenge to restoration, and appropriateness of seeds, climate, and weather variability are factors that may explain success or difficulties in big sagebrush restoration efforts. This project provided several ways of assessing climate responses of big sagebrush seedlings during the critical establishment phase post-fire. We evaluated eleven different seed sources of big sagebrush from all three subspecies, dissimilar climates-of-origin, and different ploidy levels to assess how subspecies, cytotype, and climate-of-origin affect initial establishment of sagebrush in a common garden study. We assessed ecophysiological-climate adaptation as it relates to seedling performance using a suite of dependent variables, including: survival, growth, water balance, photosynthesis, and threshold freezing responses. Results indicate the importance of minimum temperatures to seedling establishment, and reveal a gradient of physiological responses to freezing that inform big sagebrush adaptation and functional diversity. We then used in-situ experimental warming to isolate minimum temperatures, and test the effects of warming on seedling physiological performance for the three dominant subspecies of big sagebrush: A.t. tridentata, A.t. vaseyana, and A.t. wyomingensis. Experimental warming further supported our minimum temperature hypothesis, indicating that warming may alter seedling freezing response thereby affect growth and survival. In a third experiment, we evaluated how initial establishment of big sagebrush is influenced by management treatments on the herb layer, as post-fire rehabilitation frequently involves alterations of the plant community and soil. Results suggest that drill seeding combined with land management treatments that cause disturbance of the herb layer and soil surface may negatively affect sagebrush during the establishment phase. Also, seedlings from local seed or faster-growing populations had greater survival than seedlings from climates that differed from the experimental site. In summary, we provide experimental evidence for the importance of minimum temperatures and seed sources to big sagebrush ecology and management of sagebrush systems. As the climate warms, selection for population-specific freezing resistance mechanisms may alter subspecies distributions. Our data indicated that warming could increase relative abundance of A.t. tridentata compared to A.t. wyomingensis at our Birds of Prey National Conservation Areas study site on the lower Snake River plain. The underlying mechanism for this is greater stress overcome by changes in resource allocation from freezing protection to growth, as well as an extraction of deeper soil water resources in A.t. tridentata. Mortality of A.t. vaseyana appeared to relate to drought stress and greater vulnerability to minimum temperature exposure. Understanding differences in big sagebrush populations’ ability to compete with different types and abundances of herbs as well as variation in freezing resistance mechanisms will contribute to appropriate seed selection for particular restoration sites. The implication is that selection of seed is critical for big sagebrush restoration success

Challenges of Establishing Big Sagebrush (\u3cem\u3eArtemisis tridentata\u3c/em\u3e) in Rangeland Restoration: Effects of Herbicide, Mowing, Whole-Community Seeding, and Sagebrush Seed Sources

The loss of big sagebrush (Artemisia tridentata Nutt.) on sites disturbed by fire has motivated restoration seeding and planting efforts. However, the resulting sagebrush establishment is often lower than desired, especially in dry areas. Sagebrush establishment may be increased by addressing factors such as seed source and condition or management of the plant community. We assessed initial establishment of seeded sagebrush and four populations of small outplants (from different geographies, climates, and cytotypes) and small sagebrush outplants in an early seral community where mowing, herbicide, and seeding of othre native plants had been experimentally applied. No emergence of seeded sagebrush was detected. Mowing the site before planting seedlings led to greater initial survival probabilities for sagebrush outplants, except where seeding also occured, and these effects were related to corresponding changes in bare soil exposure. Initial survivial probabilities were \u3e30% for the local population of big sagebrush relative to populations imported to the site from typical seed transfer distances of ~320-800 km. Overcoming the high first-year mortality of outplanted or seeded sagebrush is one of the most challenging aspects of postfire restoration and rehabilitation, and further evaluation of the impacts of herb treatments and sagebrush seed source across different site types and years is needed

Corrigendum to “Challenges of establishing big sagebrush (Artemisia tridentata) in rangeland restoration: Effects of herbicide, mowing, whole-community seeding, and sagebrush seed sources” [Rangeland Ecology & Management 68 (2015) 432–435]

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Effectiveness of Managing Cheatgrass and Other Fine Fuels in Non-Native Dominated Sagebrush Ecological Sites

Managing fire risk by reducing nonnative plants and restoring native plant communities is paramount to habitat conservation and implementing mandates such as Secretarial Order (3336) for Rangeland Fire Prevention, Management and Restoration in the western United States. Nowhere will this effort be more challenging than in the low precipitation (\u3c8-10 inch) areas where repeated fires have resulted in conversion of big sagebrush communities to nonnative annual grasses and forbs. To evaluate potential restoration actions in these dry sites, we treated 48 1-ha experimental plots in nonnative plantdominated communities located within three large replicate blocks with a full-factorial, completely randomized combination of fuel reduction/native plant restoration treatments: mowing, mowing + herbicide, herbicide application, and control (no treatment), with half of all plots seeded with native species. We also out-planted big sagebrush seedlings in some plots the growing season following seeding. Preliminary results suggest that treatment effects on fuels either disappear within the first year, or are often overshadowed by effects of inter-annual variability in precipitation. Seeding of native species was mostly unsuccessful, and out-planted sagebrush seedlings survived for a limited duration during the growing season, likely due to drought conditions. Survival probabilities for sagebrush seedlings did increase with mowing, except when followed by seeding, probably because the soil disturbance from the minimum-till drill led to less bare ground cover. Treatments had no significant effects on soil C decomposition or N mineralization rates. Thus, changes in soil nutrients were unlikely to explain observed treatment effects, or the lack thereof

Effectiveness of Managing Cheatgrass and Other Fine Fuels in Non-Native Dominated Sagebrush Ecological Sites

Managing fire risk by reducing nonnative plants and restoring native plant communities is paramount to habitat conservation and implementing mandates such as Secretarial Order (3336) for Rangeland Fire Prevention, Management and Restoration in the western United States. Nowhere will this effort be more challenging than in the low precipitation (\u3c8-10 inch) areas where repeated fires have resulted in conversion of big sagebrush communities to nonnative annual grasses and forbs. To evaluate potential restoration actions in these dry sites, we treated 48 1-ha experimental plots in nonnative plantdominated communities located within three large replicate blocks with a full-factorial, completely randomized combination of fuel reduction/native plant restoration treatments: mowing, mowing + herbicide, herbicide application, and control (no treatment), with half of all plots seeded with native species. We also out-planted big sagebrush seedlings in some plots the growing season following seeding. Preliminary results suggest that treatment effects on fuels either disappear within the first year, or are often overshadowed by effects of inter-annual variability in precipitation. Seeding of native species was mostly unsuccessful, and out-planted sagebrush seedlings survived for a limited duration during the growing season, likely due to drought conditions. Survival probabilities for sagebrush seedlings did increase with mowing, except when followed by seeding, probably because the soil disturbance from the minimum-till drill led to less bare ground cover. Treatments had no significant effects on soil C decomposition or N mineralization rates. Thus, changes in soil nutrients were unlikely to explain observed treatment effects, or the lack thereof

Venous Thromboembolism Risk and Prophylaxis in the Acute Care Hospital Setting (ENDORSE Survey) Findings in Surgical Patients

Objective: To evaluate venous thromboembolism (VTE) risk in patients who underwent a major operation, including the use of, and factors influencing, American College of Chest Physicians-recommended types of VTE prophylaxis

Venous thromboembolism risk and prophylaxis in hospitalised medically ill patients The ENDORSE Global Survey

Limited data are available regarding the risk for venous thromboembolism (VIE) and VIE prophylaxis use in hospitalised medically ill patients. We analysed data from the global ENDORSE survey to evaluate VTE risk and prophylaxis use in this population according to diagnosis, baseline characteristics, and country. Data on patient characteristics, VIE risk, and prophylaxis use were abstracted from hospital charts. VTE risk and prophylaxis use were evaluated according to the 2004 American College of Chest Physicians (ACCP) guidelines. Multivariable analysis was performed to identify factors associated with use of ACCP-recommended prophylaxis. Data were evaluated for 37,356 hospitalised medical patients across 32 countries. VIE risk varied according to medical diagnosis, from 31.2% of patients with gastrointestinal/hepatobiliary diseases to 100% of patients with acute heart failure, active noninfectious respiratory disease, or pulmonary infection (global rate, 41.5%). Among those at risk for VTE, ACCP-recommended prophylaxis was used in 24.4% haemorrhagic stroke patients and 40-45% of cardiopulmonary disease patients (global rate, 39.5%). Large differences in prophylaxis use were observed among countries. Markers of disease severity, including central venous catheters, mechanical ventilation, and admission to intensive care units, were strongly associated with use of ACCP-recommended prophylaxis. In conclusion, VIE risk varies according to medical diagnosis. Less than 40% of at-risk hospitalised medical patients receive ACCP-recommended prophylaxis. Prophylaxis use appears to be associated with disease severity rather than medical diagnosis. These data support the necessity to improve implementation of available guidelines for evaluating VIE risk and providing prophylaxis to hospitalised medical patients