DOI: 10.5061/dryad.m49k6
title: Data from: Fatal attraction: vegetation responses to nutrient inputs attract herbivores to infectious anthrax carcass sites

description: Parasites can shape the foraging behaviour of their hosts through cues
 indicating risk of infection. When cues for risk co-occur with desired
 traits such as forage quality, individuals face a trade-off between
 nutrient acquisition and parasite exposure. We evaluated how this
 trade-off may influence disease transmission in a 3-year experimental
 study of anthrax in a guild of mammalian herbivores in Etosha National
 Park, Namibia. At plains zebra (Equus quagga) carcass sites we assessed
 (i) carcass nutrient effects on soils and grasses, (ii) concentrations of
 Bacillus anthracis (BA) on grasses and in soils, and (iii) herbivore
 grazing behaviour, compared with control sites, using motion-sensing
 camera traps. We found that carcass-mediated nutrient pulses improved soil
 and vegetation, and that BA is found on grasses up to 2 years after death.
 Host foraging responses to carcass sites shifted from avoidance to
 attraction, and ultimately to no preference, with the strength and
 duration of these behavioural responses varying among herbivore species.
 Our results demonstrate that animal carcasses alter the environment and
 attract grazing hosts to parasite aggregations. This attraction may
 enhance transmission rates, suggesting that hosts are limited in their
 ability to trade off nutrient intake with parasite avoidance when relying
 on indirect cues.
description: Soil nutrient data from
 carcass sitesSoil nutrient data
 collected at anthrax negative, plains zebra carcass sites one, two and
 three years after death. Samples were collected 0, 1.5, 4.5 and 7.5m from
 carcass centers. Soil characteristics measured include pH, organic matter,
 P, K, Ca, Mg, Na and Kjeldhal N.soil_nutrient_data.csvGrass biomass and nitrogen data from carcass sitesGrass data collected at anthrax negative, plains zebra carcass sites one, two and three years after death. Samples were collected 1.5m (zone 1), 4.5m (zone 2) and 7.5m (zone 3) from carcass centers. Measurements include grass biomass (g/m^2) averaged across the two replicate quadrats sampled and grass nitrogen, measured as Kjeldahl N. NA values for nitrogen samples were of insufficient mass for analysis.grass_nutrient_data.csvBacillus anthracis measurements at carcass sitesBacillus anthracis (BA) colony forming units (CFU)/g measured at plains zebra anthrax positive carcass sites one, two or three years after death. Samples include the above ground component of grass ("grass"), the roots and soil surrounding the plant ("soil"). CFU measurements here are an average of three replicate plant and soil samples collected at each site.BA_CFU_data.csvCamera trap data from carcass and control sitesGrazing and visitation data collected using motion sensing camera traps at anthrax carcass or control sites (camera= Carcass or Control), for springbok (AM), plains zebra (EQ), gemsbok (OG) or blue wildebeest (CT). "gap" refers to whether the paired camera from the site was functional or not when that particular photo sequence was recorded (N=no, there was no gap in the other camera, Y=yes, there was a gap, i.e. the paired camera was not functioning). Number_grazing is the number of individuals observed grazing during the photo sequence; number_in_rocks is the number of individuals observed within the rock-defined site during the photo sequence.camera_trap_grazing_data.csv