Modelling the impacts of agriculture in mixed-use landscapes: a review and case study involving two species of dabbling ducks

Context

This study synthesizes evidence from three separate surveys of American Black Duck and Mallard breeding habitat usage to quantify the effects of agriculture at the landscape scale.

Objectives

To assess duck breeding activity in agricultural landscapes within the Canadian maritimes in order to measure the overall impact of agricultural land use, the response to particular agricultural activities, and the influence of landscape configuration.

Methods

Models, constructed using a long-term census (SURVEY1), were used to predict habitat selection for two other independent surveys (SURVEY2, SURVEY3). Predictions incorporated information about wetland area and diversity, as well as anthropogenic factors, allowing subsequent analyses to focus on the remaining residual error attributable to agricultural effects.

Results

SURVEY2 results demonstrated that the proportion of active agriculture is an important indicator of the severity of human disturbance, yielding threshold estimates of 39% for Mallards and 60% for Black Ducks, with an overall average of 50%. Agricultural conversion beyond these thresholds deterred breeding ducks independently of other factors. SURVEY3 land cover information demonstrated that the presence of cropland intensified this deterrence effect, even at levels as low as 10%. Woodland cover (in excess of 30%) was important for both species, but its configuration was not.

Conclusions

In addition to quantifying threshold effects, this study reaffirms that woodland is an important part of the maritime landscape matrix, and contributes positively to habitat diversity in mixed use, moderate intensity agricultural regions. Wetland restoration in agricultural landscapes should monitor and promote less crop-intensive, mixed-use practices.

     

Listeria monocytogenes septicemia in an immunocompromised dog

An 11‐year‐old, male castrated, Boston Terrier was presented to the North Carolina State University College of Veterinary Medicine Small Animal Emergency Service with a 2‐day history of progressive ataxia, left‐sided head tilt, and anorexia. The dog had previously been diagnosed with chronic lymphoid leukemia and suspected immune‐mediated destruction of his bone marrow precursor cells, possibly due to therapy with immunosuppressive dosages of prednisone and azathioprine. During the physical examination, abnormal findings included an increased body temperature and horizontal nystagmus. Diagnostic investigations included a computed tomography (CT) scan, which confirmed bilateral otitis media, and a blood culture, which was positive for Listeria monocytogenes serotype 4b (epidemic clone 1). Upon treatment with ampicillin/sulbactam, enrofloxacin, and minocycline, the dog became normothermic and the neurologic signs improved. L monocytogenes serotype 4b (epidemic clone 1) has been associated with outbreaks of human listeriosis originating from food contamination. Although rare case reports of Listeria spp. infection in dogs exist, an actual infection with the epidemic clone 1 strain has never before been reported in a dog. It should be included in the differential diagnoses in immunocompromised dogs with clinical signs of septicemia.     

Surgical resection of an osteoma of two thoracic spinous processes in a horse

This report describes the successful surgical removal of an osteoma of the thoracic dorsal spinous processes of a horse that presented with back pain. Osteomas of the spine are frequently reported in the literature in people, but have not been previously described in the horse.     

Synergisms in Science: Climate Change and Integrated Pest Management Through the Lens of Communication—2019 Student Debates

Every year, the Student Debates Subcommittee (SDS) of the Student Affairs Committee (SAC) for the annual Entomological Society of America (ESA) meeting organizes the Student Debates. This year, the SAC selected topics based on their synergistic effect or ability to ignite exponential positive change when addressed as a whole. For the 2019 Student Debates, the SAC SDS identified these topic areas for teams to debate and unbiased introduction speakers to address: 1) how to better communicate science to engage the public, particularly in the area of integrated pest management (IPM), 2) the influential impacts of climate change on agriculturally and medically relevant insect pests, and 3) sustainable agriculture techniques that promote the use of IPM to promote food security. Three unbiased introduction speakers gave a foundation for our audience to understand each debate topic, while each of six debate teams provided a strong case to support their stance or perspective on a topic. Debate teams submitted for a competitive spot for the annual ESA Student Debates and trained for the better part of a year to showcase their talents in presenting logical arguments for a particular topic. Both the debate teams and unbiased introduction speakers provided their insight toward a better understanding of the complexities of each topic and established a foundation to delve further into the topics of science advocacy and communication, climate change, and the many facets of integrated pest management.