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Disease or drought: Environmental fluctuations release zebra from a potential pathogen-triggered ecological trap

Citation

Huang, Yen-Hua et al. (2021), Disease or drought: Environmental fluctuations release zebra from a potential pathogen-triggered ecological trap, Dryad, Dataset, https://doi.org/10.5061/dryad.b2rbnzsdv

Abstract

When a transmission hotspot for an environmentally persistent pathogen establishes in otherwise high-quality habitat, the disease may exert a strong impact on a host population. However, fluctuating environmental conditions lead to heterogeneity in habitat quality and animal habitat preference, which may interrupt the overlap between selected and risky habitats. We evaluated spatiotemporal patterns in anthrax mortalities in a plains zebra (Equus quagga) population in Etosha National Park, Namibia, incorporating remote-sensing and host telemetry data. A higher proportion of anthrax mortalities of herbivores was detected in open habitats than in other habitat types. Resource selection functions showed that the zebra population shifted habitat selection in response to changes in rainfall and vegetation productivity. Average to high rainfall years supported larger anthrax outbreaks, with animals congregating in preferred open habitats, while a severe drought forced animals into otherwise less preferred habitats, leading to few anthrax mortalities. Thus, the timing of anthrax outbreaks was congruent with preference for open plains habitats and a corresponding increase in pathogen exposure. Given shifts in habitat preference, the overlap in high-quality habitat and high-risk habitat is intermittent, reducing the adverse consequences for the population.

Methods

These files include:

1.R code for analyses and figure generation for the study.

2.Annual rainfall recorded in Okaukuejo station at central Etosha National Park, Namibia (ENP) 1954-2020.

3.Average fraction of photosynthetically active radiation (FPAR) data across the study area during the study periods (2009-2010; 2018-2019), originally downloaded from NASA LP DAAC.

4.Plains zebra (Equus quagga) anthrax mortality in ENP 1980-2020.

5.Mortality with spatial information (habitat type) in ENP 1998-2020 for zebra, blue wildebeest (Connochaetes taurinus), gemsbok (Oryx gazella), springbok (Antidorcas marsupialis) and greater kudu (Tragelaphus strepsiceros).

6.Zebra telemetry data thinned with readings closest to 9:00, 15:00 and 24:00, during May 2009 – August 2010 and October 2018 – April 2020, with 10-time random points generated for habitat seleciton analysis.

7.Zebra telemetry data thinned with fixed intervals of 1, 2, 4, 8, 12, 24 hours, during May 2009 – August 2010, with 10-time random points generated for habitat seleciton analysis.

Funding

National Science Foundation, Award: DEB-1816161/DEB-2106221

National Institutes of Health, Award: GM083863

U.S. Department of Agriculture, Award: ME021908

University at Albany