title: Risk factors for elevated Enterococcus concentrations in a rural tropical island watershed.
abstract: Associations were examined between riparian canopy cover, presence of cattle near streams, and month of year with the concentration of Enterococcus (Most Probable Number (MPN)/100 ml) in surface water at Waipā watershed on the North Side of the Hawaiian island Kaua'i. Each one percent decrease in riparian canopy cover was associated with a 3.6 MPN/100 ml increase of waterborne Enterococcus. Presence of cattle near monitoring sites was associated with an increase of 99.3 MPN/100 ml of Enterococcus in individual grab samples. Lastly, summer samples (July) were substantially higher in concentration of Enterococcus than winter collected samples (February) in Enterococcus in sampled streams. These results suggest that reducing canopy cover and introduction of cattle into riparian zones may contribute to increases of Enterococcus concentrations in stream water.
authors.affiliation: Watershed Manager, Surfing Medicine International 501(c)(3), PO Box 548, Waialua, Hawaii 96791, USA. surfingmedicine@gmail.com
authors.forename: Guy
authors.initials: G
authors.lastname: Ragosta
authors.forename: Carl
authors.initials: C
authors.lastname: Evensen
authors.forename: E R
authors.initials: ER
authors.lastname: Atwill
authors.forename: Mark
authors.initials: M
authors.lastname: Walker
authors.forename: Tamara
authors.initials: T
authors.lastname: Ticktin
authors.forename: Adam
authors.initials: A
authors.lastname: Asquith
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Tate
mesh_terms: D000383:Agriculture; D000818:Animals; D002417:Cattle; D016983:Enterococcus; D006254:Hawaii; D011157:Population Dynamics; D012307:Risk Factors; D045483:Rivers / Q000382:microbiology*; D012621:Seasons; D014197:Trees; D014329:Tropical Climate; D014871:Water Microbiology