skip to main content


Search for: All records

Creators/Authors contains: "Gonthier, David J."

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Abstract

    Recent foodborne illness outbreaks have heightened pressures on growers to deter wildlife from farms, jeopardizing conservation efforts. However, it remains unclear which species, particularly birds, pose the greatest risk to food safety. Using >11,000 pathogen tests and 1565 bird surveys covering 139 bird species from across the western United States, we examined the importance of 11 traits in mediating wild bird risk to food safety. We tested whether traits associated with pathogen exposure (e.g., habitat associations, movement, and foraging strategy) and pace‐of‐life (clutch size and generation length) mediated foodborne pathogen prevalence and proclivities to enter farm fields and defecate on crops.Campylobacterspp. were the most prevalent enteric pathogen (8.0%), whileSalmonellaand Shiga‐toxin producingEscherichia coli(STEC) were rare (0.46% and 0.22% prevalence, respectively). We found that several traits related to pathogen exposure predicted pathogen prevalence. Specifically,Campylobacterand STEC‐associated virulence genes were more often detected in species associated with cattle feedlots and bird feeders, respectively.Campylobacterwas also more prevalent in species that consumed plants and had longer generation lengths. We found that species associated with feedlots were more likely to enter fields and defecate on crops. Our results indicated that canopy‐foraging insectivores were less likely to deposit foodborne pathogens on crops, suggesting growers may be able to promote pest‐eating birds and birds of conservation concern (e.g., via nest boxes) without necessarily compromising food safety. As such, promoting insectivorous birds may represent a win‐win‐win for bird conservation, crop production, and food safety. Collectively, our results suggest that separating crop production from livestock farming may be the best way to lower food safety risks from birds. More broadly, our trait‐based framework suggests a path forward for co‐managing wildlife conservation and food safety risks in farmlands by providing a strategy for holistically evaluating the food safety risks of wild animals, including under‐studied species.

     
    more » « less
  2. Abstract

    Bird conservation in agricultural settings can be controversial. While some bird species damage some crops, others suppress insect pests. Few studies have simultaneously compared bird services and disservices to assess their net impact.

    Using an exclusion experiment in six California strawberry farms, we show that bird suppression of berry damage by insect pests (about 3.8% of berries) is similar in magnitude to the damage birds inflict on strawberries (about 3.2% of berries).

    Across 27 farms, we found that bird species richness and the relative abundance of insectivorous birds increased, while the relative abundance of strawberry‐eating birds and bird damage decreased on farms with more semi‐natural land cover in the surrounding landscapes (1000 m radius).

    Relative to homogeneous farms, those that implemented diversification practices, such as hedgerows, flower strips or increased crop diversity, had greater bird species richness, total relative abundance, insectivore abundance and strawberry‐eating bird abundance.

    Synthesis and applications. Conserving semi‐natural land cover in the surrounding landscape benefits bird species richness locally and aids farmers through reduced abundance of strawberry‐eating birds and bird damage. These results highlight the need to consider both the services and disservices of birds when making management decisions.

     
    more » « less
  3. Abstract

    Whether an ecological community is controlled from above or below remains a popular framework that continues generating interesting research questions and takes on especially important meaning in agroecosystems. We describe the regulation from above of three coffee herbivores, a leaf herbivore (the green coffee scale, Coccus viridis), a seed predator (the coffee berry borer, Hypothenemus hampei), and a plant pathogen (the coffee rust disease, caused by Hemelia vastatrix) by various natural enemies, emphasizing the remarkable complexity involved. We emphasize the intersection of this classical question of ecology with the burgeoning field of complex systems, including references to chaos, critical transitions, hysteresis, basin or boundary collision, and spatial self-organization, all aimed at the applied question of pest control in the coffee agroecosystem.

     
    more » « less