Ungrazed seminatural habitats around farms benefit bird conservation without enhancing infectious disease risks

Context   Conservation in working landscapes is critical for
halting biodiversity declines and ensuring farming system sustainability.
However, concerns that wildlife may carry foodborne pathogens has created
pressure on farmers to remove habitat and reduce biodiversity, undermining
farmland conservation. Nonetheless, simplified farming landscapes may host
bird communities that carry higher foodborne disease risks.  
Objectives   We analyzed the effects of local farming practices
and surrounding landscapes on bird communities and food-safety risks
across 30 California lettuce farms. Specifically, we sought to determine
how farmland diversification affects bird diversity, fecal contamination,
and foodborne pathogen incidences, thereby identifying potential tradeoffs
between managing farms for bird conservation versus food safety.
  Methods   We surveyed birds at 227 point-count
locations, quantified fecal contamination along 120 transects, and assayed
601 bird feces for pathogenic E. coli, Campylobacter spp., and Salmonella
spp. We then used hierarchical models to quantify effects of farm
management and landscape context on bird communities and food-safety
risks.   Results   Surrounding ungrazed seminatural
areas were associated with higher bird diversity, more species of
conservation concern, and fewer flocks that may increase risks from
foodborne pathogens. In contrast, on-farm diversification practices and
surrounding grazing lands offered weaker bird conservation benefits.
Surrounding grazed lands were associated with more potentially pathogenic
bird feces in crop fields.     Conclusions
  Our results suggest that habitat conservation around produce
farms could support bird conservation without increasing foodborne
pathogens, especially on farms further from grazing lands. Thus,
interventions that diversify farming systems offer potential to
simultaneously conserve biodiversity and provide safe food for human
consumption.