Human-induced disease outbreak in animals causes cascading ecological
effects
The increased spread of human-induced diseases to wildlife poses a
growing challenge for ecosystem conservation

Date:
March 7, 2022
Source:
Yale University
Summary:
A study that investigated the impacts of a mange outbreak that
killed vicunas in a protected area in the Argentine Andes found
that it had unique effects on the ecology of the region.



FULL STORY ==========================================================================
A Yale School of the Environment-led study that investigated the impacts
of a mange outbreak that killed vicun~as in a protected area in the
Argentine Andes found that it had unique effects on the ecology of
the region.


==========================================================================
The study published in Ecology Letters is unique in that it tracked the cascading effects of the deaths of the vicun~as, which are wild South
American camelids, from the disease on vegetation and biodiversity in
the region.

"We largely don't have many examples in literature of how a rapid-disease outbreak can cause effects, not just on populations, but throughout the ecosystem. So, this provides really important context,'' says YSE PhD
student Julia Monk, a lead author of the study.

Monk, a student in the lab of YSE Oastler Professor of Population and
Community Ecology Oswald Schmitz, who also co-authored the report,
was doing field work in the high desert of San Guillermo National Park
in the Andes when mange ravaged the vicun~as. She was studying the
important role that pumas and their prey play in carbon storage and
nutrient cycling on landscapes.

The impact of the loss of vicun~as from disease were significantly
different than the deaths of vicun~as by predation from pumas, Monk and
a team of researchers discovered.

"What is really different about what we found was that we were able to
track the change in ecosystem function, from a system governed by pumas
as the top predator to a system dominated by this disease and to determine
that they're not analogous. You don't just swap out one for the other. We actually had completely diverging outcomes based on which was a dominant
source of mortality for these vicun~as,'' says Justine Smith, assistant professor of ?wildlife, fish, and conservation biology at University of California, Davis, who was co- lead author of the study. The deaths from
mange led to an increase in vegetation as well as a reduced presence
of condors, that forage off vicun~as carcasses killed by pumas in the
national park.



========================================================================== "Disease transmission between wildlife and domestic animals can
be catastrophic for both players, threatening local livelihoods and
disrupting natural processes in protected areas. As land use modification
and fragmentation continue to increase interactions between domestic and
wild animals, disease- dominated trophic cascades may come to supplant predators as top-down forces in some systems,'' the study notes.

Recent research indicates the outbreak of mange was linked to domestic
llamas that were released outside the park.

Smith says the study points to the importance of tracking the effects
of disease outbreaks globally.

"It's hard for us to anticipate all of the ways that people can
change ecosystems. There are a lot of interacting effects, and I think
we're going to continue to see rapidly restructured ecosystems,'' says
Smith. "And that is something that we need to learn a lot more about if
we're going to create conservation plans in the changing world that we
live in." The study highlights the need to prepare for more impacts of human-induced wildlife disease outbreaks and how it affects conservation.

"Developing strategies for human-wildlife coexistence and protected
areas management that minimize the exchange and spread of disease will be critical for the conservation of ecosystems sustained by tightly connected
food webs as well as the preservation of human health and livelihoods,''
the study states.

Schmitz says when nature threw Monk and Smith a curveball in the field
when the disease broke out, they quickly were able to recognize important analysis.

"They co-led an environmental data science analysis comprehensively
showing how an explosive disease outbreak, could quickly unravel a
long-running ecosystem state, in a putative protected area no less. It
is a sober reminder of how human transformation of the planet outside
of protected areas can have unintended but far-reaching, consequences,'' Schmitz says.

========================================================================== Story Source: Materials provided by Yale_University. Note: Content may
be edited for style and length.


========================================================================== Journal Reference:
1. Julia D. Monk, Justine A. Smith, Emiliano Donadi'o, Paula L. Perrig,
Ramiro D. Crego, Martin Fileni, Owen Bidder, Sergio A. Lambertucci,
Jonathan N. Pauli, Oswald J. Schmitz, Arthur D. Middleton. Cascading
effects of a disease outbreak in a remote protected area. Ecology
Letters, 2022; DOI: 10.1111/ele.13983 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220307190607.htm

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