WEDELIA: A POTENTIAL GROUND COVER FOR REDUCING THE ATTRACTIVENESS OF TROPICAL AIRFIELDS TO BIRDS

Airport environments frequently provide ideal feeding and loafing habitats for many bird species. Bird strikes at most airports involve predominantly insectivorous species. However, the Lihue Airport on the island of Kauai, Hawaii has had a severe problem with bird strikes involving 4 granivorous species: the zebra dove (Geopelia striata), spotted dove (Streptopelia chinensis), chestnut mannikin (Lonchura malacca), and nutmeg mannikin (L. punctulato). Two owl species, the common barn owl (Tyto alba) and Hawaiian short-eared owl (Asio flammeus sandwhichensis), have also been involved in aircraft collisions at Lihue. Shooting and hazing techniques to disperse birds have proven ineffective or unacceptable; therefore, an alternative ground cover, wedelia (Wedelia trilobata), was tested to determine if the airfield environment could be rendered unattractive to birds. Volunteer stands of wedelia throughout the airfield were delineated and additional plantings established. We used bird activity, exclusion of seed-producing plants, rodent abundance, and invertebrate populations as indicators of effectiveness. Utilization of test plots by rodents and the four major seed-eating birds was significantly lower than in the corresponding control plots. The nearly monotypic stands of wedelia resulted in decreased seed availability to birds and rodents. Because of the ease of establishing and maintaining wedelia on airfields, its dominance over palatable seed producing plants, exclusion of rodent populations, low fire hazard, and decreased utilization by critical bird species, wedelia shows great promise as an alternative ground cover in tropical airfield environments

Using wedelia as ground cover on tropical airports to reduce bird activity

aircraft collisions (i.e., bird strikes) are a major problem at airports worldwide, often because birds are attracted to airfields to feed on seeds, insects, or rodents that abound in the grassy areas near runways and taxiways. We compared an alternative ground cover, wedelia (Wedelia trilobata), to existing vegetation (control plots) on the airfield at Lihue Airport, Kauai, Hawaii, to determine if bird populations on the airport could be reduced by eliminating their forage base. We studied wedalia because it is a low-growing plant that did not need mowing, was easily established in plots, and out-competed other plants, resulting in a significant decrease in plant diversity. Thus, wedelia indirectly results in a decreased seed base for granivorous birds. Total invertebrate biomass was 41% lower in wedelia plots than in other vegetation plots (control plots). Rodent populations were 67% lower in wedelia than in control plots. Zebra doves (Geopelia striata), spotted doves (Streptopelia chinensis), and mannikins (Lonchura spp.) used wedelia plots significantly less than control plots, whereas, the lesser Pacific golden-plover (Pluvialis fulva) was unaffected. By reducing seed production, insect densities, and rodant populations, wedalia should be a useful ground cover on tropical airports to reduce bird use and, ultimately, bird strikes on the airport

Hydrodynamic Modeling of Krypton and Xenon Propellant Performance in a Hall Thruster

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76147/1/AIAA-2007-5210-907.pd

Bird Use of Stormwater-Management Ponds: Decreasing Avian Attractants on Airports

Characteristics of stormwater-management ponds that contribute to avian hazards to aviation at airports have not been quantified. We selected 30 stormwater-management ponds (average 0.1 ha), approximately 50km from Seattle-Tacoma International Airport, as surrogates to on-airport facilities. We conducted 46 weeks of avian surveys (between 14 February 2005 and 17 February 2006) and evaluated model fit of 6 a priori models relative to pond use by an avian group via Kullback–Leibler information. Our full model, composed of pond surface area (sa), ratio of area of open water to area of emergent and woody vegetation (ow:ew), perimeter irregularity, and geographic isolation, was among 3 best approximating models for pond use by 9 of 13 groups (within Anatidae, Ardeidae, Charadriidae, Columbidae, Accipitridae, Laridae, and Rallidae) considered. The full model and models lacking sa or ow:ew were indistinguishable in fit for a group composed of avian species considered hazardous to aviation. For models selected, Akaike weights (i.e., relative likelihoods) ranged from 0.869 to 0.994. In contrast, relative likelihood for a mean model (i.e., a model including only an intercept) was \u3c10−4 for all groups. We suggest that designs of stormwater management ponds at airports in the Pacific Northwest should minimize the pond perimeter via circular or linear designs. Also, ponds should be located so as to reduce the number and proximity of other water resources within 1 km. For existing stormwater-management ponds at airports, we suggest reducing the availability of open water via covering or drawdown

Behavioral responses of terrestrial mammals to COVID-19 lockdowns

COVID-19 lockdowns in early 2020 reduced human mobility, providing an opportunity to disentangle its effects on animals from those of landscape modifications. Using GPS data, we compared movements and road avoidance of 2300 terrestrial mammals (43 species) during the lockdowns to the same period in 2019. Individual responses were variable with no change in average movements or road avoidance behavior, likely due to variable lockdown conditions. However, under strict lockdowns 10-day 95th percentile displacements increased by 73%, suggesting increased landscape permeability. Animals' 1-hour 95th percentile displacements declined by 12% and animals were 36% closer to roads in areas of high human footprint, indicating reduced avoidance during lockdowns. Overall, lockdowns rapidly altered some spatial behaviors, highlighting variable but substantial impacts of human mobility on wildlife worldwide.acceptedVersio

Archiving primary data: solutions for long-term studies

The recent trend for journals to require open access to primary data included in publications has been embraced by many biologists, but has caused apprehension amongst researchers engaged in long-term ecological and evolutionary studies. A worldwide survey of 73 principal investigators (Pls) with long-term studies revealed positive attitudes towards sharing data with the agreement or involvement of the PI, and 93% of PIs have historically shared data. Only 8% were in favor of uncontrolled, open access to primary data while 63% expressed serious concern. We present here their viewpoint on an issue that can have non-trivial scientific consequences. We discuss potential costs of public data archiving and provide possible solutions to meet the needs of journals and researchers