21 research outputs found
Mammal-exclusion fencing improves the nesting success of an endangered native Hawaiian waterbird
Invasive predator control is often critical to improving the nesting success of endangered birds, but methods of control vary in cost and effectiveness. Poison-baiting or trapping and removal are relatively low-cost, but may have secondary impacts on non-target species, and may not completely exclude mammals from nesting areas. Mammal-exclusion fencing has a substantial up-front cost, but due to cost savings over the lifetime of the structure and the complete exclusion of mammalian predators, this option is increasingly being utilized to protect threatened species such as ground-nesting seabirds. However, non-mammalian predators are not excluded by these fences and may continue to impact nesting success, particularly in cases where the fence is designed for the protection of waterbirds, open to an estuary or wetland on one side. Thus, there remains a research gap regarding the potential gains in waterbird nesting success from the implementation of mammal-exclusion fencing in estuarine systems. In this study, we compared the nesting success of endangered Hawaiian Stilts (Ae‘o; Himantopus mexicanus knudseni) within a mammal-exclusion fence to that of breeding pairs in a nearby wetland where trapping was the sole means for removing invasive mammals. We predicted success would be greater for breeding pairs inside the exclusion fence and the hatchlings inside the enclosure would spend more time in the nesting area than hatchlings at the unfenced site. During a single breeding season following construction of a mammal-exclusion fence, we used motion-activated game cameras to monitor nests at two sites, one site with mammal-exclusion fencing and one site without. Clutch sizes and hatch rates were significantly greater at the fenced site than the unfenced site, but time spent by chicks in the nesting area did not differ between sites. These results add to the mounting body of evidence that demonstrates the effectiveness of mammal-exclusion fencing in protecting endangered birds and suggests it can aid endangered Hawaiian waterbirds toward recovery. These results also suggest that the single greatest predatory threat to the Hawaiian Stilt may be invasive mammals, despite a host of known non-mammalian predators including birds, crabs, turtles, and bullfrogs, as the complete exclusion of mammals resulted in significant gains in nesting success. As additional fences are built, future studies are necessary to compare nesting success among multiple sites and across multiple seasons to determine potential gains in fledging success and recruitment
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The hydrology of the humid tropics
Hydrological processes in the humid tropics differ from other regions in having greater energy inputs and faster rates of change, including human-induced change. Human influences on population growth, land use and climate change will profoundly influence tropical hydrology, yet understanding of key hydrological interactions is limited. We propose that efforts to collect tropical data should explicitly emphasize characterizing moisture and energy fluxes from below the ground surface into the atmosphere. Research needs to chiefly involve field-based characterizations and modelling of moisture cycling and catchment processes, as well as long-term data acquisition and organization
Enhanced Immunogenicity, Mortality Protection, and Reduced Viral Brain Invasion by Alum Adjuvant with an H5N1 Split-Virion Vaccine in the Ferret
Pre-pandemic development of an inactivated, split-virion avian influenza vaccine is challenged by the lack of pre-existing immunity and the reduced immunogenicity of some H5 hemagglutinins compared to that of seasonal influenza vaccines. Identification of an acceptable effective adjuvant is needed to improve immunogenicity of a split-virion avian influenza vaccine.No serum antibodies were detected after vaccination with unadjuvanted vaccine, whereas alum-adjuvanted vaccination induced a robust antibody response. Survival after unadjuvanted dose regimens of 30 µg, 7.5 µg and 1.9 µg (21-day intervals) was 64%, 43%, and 43%, respectively, yet survivors experienced weight loss, fever and thrombocytopenia. Survival after unadjuvanted dose regimen of 22.5 µg (28-day intervals) was 0%, suggesting important differences in intervals in this model. In contrast to unadjuvanted survivors, either dose of alum-adjuvanted vaccine resulted in 93% survival with minimal morbidity and without fever or weight loss. The rarity of brain inflammation in alum-adjuvanted survivors, compared to high levels in unadjuvanted vaccine survivors, suggested that improved protection associated with the alum adjuvant was due to markedly reduced early viral invasion of the ferret brain.Alum adjuvant significantly improves efficacy of an H5N1 split-virion vaccine in the ferret model as measured by immunogenicity, mortality, morbidity, and brain invasion
Nucleic Acid-based Detection of Bacterial Pathogens Using Integrated Microfluidic Platform Systems
The advent of nucleic acid-based pathogen detection methods offers increased sensitivity and specificity over traditional microbiological techniques, driving the development of portable, integrated biosensors. The miniaturization and automation of integrated detection systems presents a significant advantage for rapid, portable field-based testing. In this review, we highlight current developments and directions in nucleic acid-based micro total analysis systems for the detection of bacterial pathogens. Recent progress in the miniaturization of microfluidic processing steps for cell capture, DNA extraction and purification, polymerase chain reaction, and product detection are detailed. Discussions include strategies and challenges for implementation of an integrated portable platform
Seasonal patterns in nest survival of a subtropical wading bird, the Hawaiian Stilt (Himantopus mexicanus knudseni)
Nest survival is influenced by where and when birds decide to breed. For ground-nesting species, nest-site characteristics, such as vegetation height and proximity to water, may impact the likelihood of nest flooding or depredation. Further, habitat characteristics, and thus nest survival, may fluctuate across the breeding season. The Hawaiian Stilt (‘Ae‘o; Himantopus mexicanus knudseni) is an endangered Hawaiian waterbird that nests in wetlands across the Hawaiian Islands.
In this study, we used observational surveys and nest cameras to examine the impact of nest-site characteristics and day of nesting season on nest survival of the Hawaiian Stilt. Early nests had a higher chance of survival than late nests. For most of
the nesting season, taller vegetation was correlated with increased nest survival, while shorter vegetation was correlated with increased nest survival late in the nesting season. Seasonal patterns in nest survival may be due to changes in parental behavior or predator activity. Nest depredation was responsible for 55% of confirmed nest failures and introduced mammals were the primary nest predators. Our study is the first to examine seasonality in nest survival of Hawaiian Stilts and suggests that, despite longer nesting seasons and year-round occupation of wetlands, late nesters in subtropical regions may have lower nest survival than early nesters, similar to trends observed in temperate regions
Nest depredation risk increases later in the nesting season for a subtropical wading bird, the Hawaiian Stilt (Himantopus mexicanus knudseni)
Nest depredation is the leading cause of nest failure in avian species. While depredation risk largely depends on depredation pressure, it may also be influenced by the timing of the nesting season and by nest site features, such as proximity to water and vegetation height. The Hawaiian Stilt (Himantopus mexicanus knudseni) is an endangered Hawaiian waterbird that nests in wetlands across the Hawaiian Islands from February to September. The nesting season coincides with a seasonal decline in precipitation, which may impact depredation rates. In this study, we used observational surveys and nest cameras to examine the impact of nest-site characteristics and nest initiation date on nest depredation of the Hawaiian Stilt. We found that stilts preferred shorter vegetation than what was randomly available and preferred to nest in Pickleweed (Batis maritima) rather than other available plant species. However, nest-site characteristics, such as vegetation height and distance to water, did not have an impact on depredation risk. Early nests had a higher chance of survival than late nests. The number of depredated nests peaked later in the nesting season, and introduced mammals were the primary nest predators. Increasing invasive predator control later in the Hawaiian Stilt nesting season, particularly for mammalian predators, may increase nest survival of later nesters. Our study is the first to examine seasonality in nest depredation of Hawaiian Stilts and suggests that, despite longer nesting seasons and year-round occupation of wetlands, late nesters in subtropical regions may have greater depredation risk than early nesters, similar to trends observed in temperate regions
A Novel Method for Detecting Inpatient Pediatric Asthma Encounters Using Administrative Data
The Cardiac Effects of COVID-19 on Young Competitive Athletes : Results from the Outcomes Registry for Cardiac Conditions in Athletes (ORCCA)
The Outcomes Registry for Cardiac Conditions in Athletes (ORCCA) study is a large-scale prospective investigation evaluating the cardiovascular effects and outcomes of SARS-CoV-2 infection on young competitive athletes. This review provides an overview of the key results from the ORCCA study. Results from the ORCCA study have provided important insights into the clinical impact of SARS-CoV-2 infection on the cardiovascular health of young competitive athletes and informed contemporary screening and return to sport practices. Key results include defining a low prevalence of both cardiac involvement and adverse cardiovascular outcomes after SARS-CoV-2 infection and evaluating the utility of a return-to-play cardiac evaluation. Future aims of the ORCCA study include the longer-term evaluation of cardiovascular outcomes among athletes post-SARS-CoV-2 infection and the transition to investigating outcomes in young athletes with potentially high-risk genetic or structural cardiac diagnoses.Medicine, Faculty ofNon UBCReviewedFacultyResearche