Wildlife Management International

The program is a multi-institutional effort led by the University of Wisconsin-Madison Engine Research Center, partnered with WM International and the University of Central Florida, aiming to revolutionize combustion technology for medium-duty commercial vehicles. The project’s primary objective is to develop a high-efficiency mixing controlled compression ignition (MCCI) combustion strategy utilizing propane and propane/DME blends. This development is crucial because current propane-fueled spark-ignited (SI) engines operate at substantially lower efficiencies (BTE of 31.5%) than comparable modern diesel engines (37.1%). The program goal is to achieve an efficiency greater than 37.1% and enable a 15% reduction in CO2 emissions compared to current diesel engines, along with a greater than 5% reduction in total cost of ownership. The core technical challenge involves overcoming propane’s low cetane number, which resists auto-ignition, especially at low loads, while simultaneously developing a robust fuel system capable of handling these liquefied gaseous fuels at extremely high injection pressures. The project addressed this by coupling engine modeling, fundamental chemical kinetics studies, and hardware development. A high-pressure propane/DME fuel system, featuring an improved dual pump architecture, was successfully developed, fabricated, and installed in the test cell, demonstrating operation at injection pressures exceeding 1100 bar, which is necessary for effective mixing controlled combustion. Furthermore, high-flow nozzles were specifically designed and calibrated for the direct-injection system. To address the challenge of achieving stable ignition on a low cetane fuel like propane under low-load conditions, Computational Fluid Dynamics (CFD) optimization identified an innovative solution: exhaust rebreathing. This strategy uses a custom-designed camshaft to re-open the exhaust valve during the intake stroke, trapping hot residual gases to preheat the charge. Simulations demonstrated that this mechanism, combined with an optimized injection system, enables stable MCCI combustion. Unassisted propane operation required highly elevated intake conditions (180 kPa intake pressure and 90 °C intake manifold temperature) for stability; however, with the rebreathe cam installed, stable compression ignition was achieved at typical engine intake conditions (125 kPa intake pressure and 45 °C IMT). Validated CFD models project that this optimized system achieves an indicated specific fuel consumption (ISFC) near 180 g/kW-hr, corresponding to a BTE greater than 38% and achieving a 16% reduction in Brake Specific CO2 (BSCO2) compared to the baseline LPG SI engine. Engine testing using the final hardware confirmed stable compression ignition operation on neat propane with combustion phasing similar to conventional diesel fuel. Complementing the engine development, fundamental research was conducted using a high-pressure shock tube facility to collect Ignition Delay Times (IDTs) for various propane/DME blends across high pressures (up to 110 bar) and relevant temperature ranges. These data were used to modify and validate chemical kinetic mechanisms, resulting in a computationally efficient reduced mechanism of 63 species for use in engineering CFD codes. Additionally, alternative ignition methods, such as ceramic glow plugs and spark plugs, were tested under energy-assisted compression ignition (EACI) strategies, both proving effective in enabling split-injection combustion at normal intake temperatures. Economic analysis suggests that while the MCCI powertrain hardware costs approximately $3,300 more than an SI engine, the projected fuel savings due to efficiency gains result in a quick payback period of roughly 1.5 years (about 1500 hours).

ABSTRACT Many seabirds are at risk of bycatch including in pelagic and demersal longline fisheries. Bycatch mitigation methods must be informed by seabird foraging behaviour to be effective. Deep‐diving seabirds are especially vulnerable to bycatch and also increase risks for less adept divers by bringing baited hooks back to the surface. We deployed time‐depth recorders paired with geolocation sensors or GPS loggers in Aotearoa New Zealand to quantify the diving ecology of three Procellaria petrel species (combined total number of dives = 12,767), all of which are vulnerable to bycatch in longline fisheries. We present the deepest dives recorded for each species, with Westland Petrels ( Procellaria westlandica ; n = 32) reaching 17.3 m, White‐chinned Petrels ( P. aequinoctialis ; n = 14) reaching 21.7 m, and Black Petrels ( P. parkinsoni ; n = 10) reaching 38.5 m, the deepest dive recorded by a Procellaria petrel. All species dived faster than the best practice longline sink rate of 0.5 m/s. All dived throughout both day and night, but Black Petrels dived more frequently during the day, while Westland Petrels dived more frequently at night. These results suggest that simultaneous implementation of weighted branch lines, bird‐scaring lines, and night setting is necessary to reduce bycatch in pelagic longline fisheries. This integrated approach effectively protects hooks from deep‐diving Procellaria petrels and prevents them from retrieving hooks and increasing risk to other seabirds. These results also bear direct relevance for custom, target‐specific mitigation methods in demersal longline fisheries. Overall, we provide the most in‐depth investigation into Procellaria petrel diving ecology to date with wide‐ranging implications for seabird conservation globally.

ABSTRACTAimTo identify the broad‐scale oceanic migration routes (‘marine flyways’) used by multiple pelagic, long‐distance migratory seabirds based on a global compilation of tracking data.LocationGlobal.Time Period1989–2023.Major Taxa StudiedSeabirds (Families: Phaethontidae, Hydrobatidae, Diomedeidae, Procellariidae, Laridae and Stercorariidae).MethodsWe collated a comprehensive global tracking dataset that included the migratory routes of 48 pelagic and long‐distance migrating seabird species across the Atlantic, Indian, Pacific and Southern Oceans. We grouped individuals that followed similar routes, independent of species or timings of migration, using a dynamic time warping clustering approach. We visualised the routes of each cluster using a line density analysis and used knowledge of seabird spatial ecology to combine the clusters to identify the broad‐scale flyways followed by most pelagic migratory seabirds tracked to‐date at an ocean‐basin scale.ResultsSix marine flyways were identified across the world's oceans: the Atlantic Ocean Flyway, North Indian Ocean Flyway, East Indian Ocean Flyway, West Pacific Ocean Flyway, Pacific Ocean Flyway and Southern Ocean Flyway. Generally, the flyways were used bidirectionally, and individuals either followed sections of a flyway, a complete flyway, or their movements linked two or more flyways. Transhemispheric figure‐of‐eight routes in the Atlantic and Pacific oceans, and a circumnavigation flyway in the Southern Ocean correspond with major wind‐driven ocean currents.Main ConclusionsThe marine flyways identified demonstrate that pelagic seabirds have similar and repeatable migration routes across ocean‐basin scales. Our study highlights the need to account for connectivity in seabird conservation and provides a framework for international cooperation.

Although geographical differences in treatment and outcomes after stroke have been described, we lack evidence on differences in the costs of treatment between urban and nonurban regions. Additionally, it is unclear whether greater costs in one setting are justified given the outcomes achieved. We aimed to compare costs and quality-adjusted life years in people with stroke admitted to urban and nonurban hospitals in New Zealand. Observational study of patients with stroke admitted to the 28 New Zealand acute stroke hospitals (10 in urban areas) recruited between May and October 2018. Data were collected up to 12 months poststroke including treatments in hospital, inpatient rehabilitation, other health service utilization, aged residential care, productivity, and health-related quality of life. Costs in New Zealand dollars were estimated from a societal perspective and assigned to the initial hospital that patients presented to. Unit prices for 2018 were obtained from government and hospital sources. Multivariable regression analyses were conducted when assessing differences between groups. Of 1510 patients (median age 78 years, 48% female), 607 presented to nonurban and 903 to urban hospitals. Mean hospital costs were greater in urban than nonurban hospitals ($13 191 versus $11 635, P=0.002), as were total costs to 12 months ($22 381 versus $17 217, P<0.001) and quality-adjusted life years to 12 months (0.54 versus 0.46, P<0.001). Differences in costs and quality-adjusted life years remained between groups after adjustment. Depending on the covariates included, costs per additional quality-adjusted life year in the urban hospitals compared to the nonurban hospitals ranged from $65 038 (unadjusted) to $136 125 (covariates: age, sex, prestroke disability, stroke type, severity, and ethnicity). Better outcomes following initial presentation to urban hospitals were associated with greater costs compared to nonurban hospitals. These findings may inform greater targeted expenditure in some nonurban hospitals to improve access to treatment and optimize outcomes.

Efficient decision-making integrates previous experience with new information. Tactical use of misinformation can alter choice in humans. Whether misinformation affects decision-making in other free-living species, including problem species, is unknown. Here, we show that sensory misinformation tactics can reduce the impacts of predators on vulnerable bird populations as effectively as lethal control. We repeatedly exposed invasive mammalian predators to unprofitable bird odors for 5 weeks before native shorebirds arrived for nesting and for 8 weeks thereafter. Chick production increased 1.7-fold at odor-treated sites over 25 to 35 days, with doubled or tripled odds of successful hatching, resulting in a 127% increase in modeled population size in 25 years. We demonstrate that decision-making processes that respond to changes in information reliability are vulnerable to tactical manipulation by misinformation. Altering perceptions of prey availability offers an innovative, nonlethal approach to managing problem predators and improving conservation outcomes for threatened species.

Migratory marine species cross political borders and enter the high seas, where the lack of an effective global management framework for biodiversity leaves them vulnerable to threats. Here, we combine 10,108 tracks from 5775 individual birds at 87 sites with data on breeding population sizes to estimate the relative year-round importance of national jurisdictions and high seas areas for 39 species of albatrosses and large petrels. Populations from every country made extensive use of the high seas, indicating the stake each country has in the management of biodiversity in international waters. We quantified the links among national populations of these threatened seabirds and the regional fisheries management organizations (RFMOs) which regulate fishing in the high seas. This work makes explicit the relative responsibilities that each country and RFMO has for the management of shared biodiversity, providing invaluable information for the conservation and management of migratory species in the marine realm.

Abstract Invasive predators can cause population declines in native prey species, but empirical evidence linking declines of native predators to invasive prey is relatively rare. Here, we document declines in an Australian freshwater crocodile Crocodylus johnstoni population following invasion of a toxic prey species, the cane toad Rhinella marina. Thirty‐five years of standardized spotlight surveys of four segments of a large river in northern Australia revealed that the density of freshwater crocodiles decreased following toad invasion and continued to decline thereafter. Overall, intermediate‐sized freshwater crocodiles (0.6–1.2 m) were most severely impacted. Densities of saltwater crocodiles Crocodylus porosus increased over time and were generally less affected by toad arrival, although toad impacts were inconsistent across survey sections and size classes. Across the entire river, total freshwater crocodile densities declined by 69.5% between 1997 and 2013. Assessments of the status of this species within other large river systems in northern Australia, where baseline data are available from before the toads arrived, should be prioritized. Our findings highlight the importance of long‐term monitoring programmes for quantifying the impacts of novel and unforeseen threats.

Discriminant function analysis (DFA) was used to determine gender and geographic variation in the morphometrics of white-chinned petrels (Procellaria aequinoctialis) measured from fisheries bycatch in New Zealand. Samples were divided into 5 clusters based on capture location. A DFA model was created using adult breeding birds presumed to be from the 2 main locations at the Auckland Islands and Antipodes Islands. Geographic variation in head and bill, skull width, culmen, culmen depth at base, culmen width at base, right and left mid-toe and claw, tail, and right and left wing was found between birds presumed to be from the ‘Auckland’ and ‘Antipodes’ clusters, with ‘Antipodes’ birds being generally larger than ‘Auckland’ birds. Gender variation in head and bill, skull width, culmen, culmen depth at base, culmen width at base, minimum bill depth, right and left mid-toe and claw, right wing, right and left tarsus existed for ‘Auckland’ birds. Gender variation in head and bill, skull width, culmen, culmen depth at base, culmen width at base, minimum bill depth, right and left mid-toe and claw, and tail existed for ‘Antipodes’ birds. Birds in the other 3 clusters were classified as originating from the Auckland Islands or Antipodes Islands. The clustering suggested that birds from the Auckland Islands tended to forage mostly north and west, whereas birds from the Antipodes Islands foraged mostly towards the north. There were large overlaps at Puysegur Point and particularly the Chatham Rise of birds from both breeding locations. This study shows the usefulness of bycatch necropsies, and emphasises the need for further studies in geographic variation and sexual dimorphism at all New Zealand breeding locations.