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Parasites enhance resistance to drought in a coastal ecosystem.

Publication ,  Journal Article
Morton, JP; Silliman, BR
Published in: Ecology
January 2020

Parasites are more diverse and numerous than their hosts and commonly control population dynamics. Whether parasites also regulate key ecosystem processes, such as resistance to climate stress, is unclear. In southern U.S. salt marshes, drought interacts synergistically with keystone grazing to generate extensive ecosystem die-off. Field manipulations of parasite prevalence and salt stress in sediments in healthy marshes demonstrated that trematode parasites, by suppressing feeding activity of grazers that overgraze on drought-stressed plants, have the potential to slow the rate of ecosystem loss. Surveys along 1,000 km of coastline during an intense drought event revealed parasitism is common in grazers on die-off borders and that increasing infection prevalence along marsh die-off borders is negatively correlated with per capita grazing. Combined, results from this field experiment and survey suggested, but did not show, that parasites could affect rates of drought-driven salt marsh die-off. To test whether parasites can indeed protect marshes under real drought conditions, we experimentally manipulated parasite prevalence in grazers over a month-long period on active die-off borders in three North Carolina marshes. Experimentally reducing parasite prevalence markedly increased the rate of plant ecosystem decline, an effect that scaled positively with prevalence. Thus parasites, by generating a trophic cascade, indirectly enhanced ecosystem resistance to overgrazing under intense drought in these North Carolina marshes. The generality of these results across the entire range of this keystone grazer in the southeastern United States needs to be tested, employing both experiments and extensive surveys that examine how the rate of ecosystem decline is mediated by parasitism. Given the ubiquity of parasites in ecosystems, our results suggest that more research effort should be invested in examining the possible roles for parasitism in regulating ecosystem function and stability.

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Published In

Ecology

DOI

EISSN

1939-9170

ISSN

1939-9170

Publication Date

January 2020

Volume

101

Issue

1

Start / End Page

e02897

Related Subject Headings

  • Wetlands
  • Poaceae
  • Parasites
  • North Carolina
  • Ecosystem
  • Ecology
  • Droughts
  • Animals
  • 4102 Ecological applications
  • 3109 Zoology
 

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Morton, J. P., & Silliman, B. R. (2020). Parasites enhance resistance to drought in a coastal ecosystem. Ecology, 101(1), e02897. https://doi.org/10.1002/ecy.2897
Morton, Joseph P., and Brian R. Silliman. “Parasites enhance resistance to drought in a coastal ecosystem.Ecology 101, no. 1 (January 2020): e02897. https://doi.org/10.1002/ecy.2897.
Morton JP, Silliman BR. Parasites enhance resistance to drought in a coastal ecosystem. Ecology. 2020 Jan;101(1):e02897.
Morton, Joseph P., and Brian R. Silliman. “Parasites enhance resistance to drought in a coastal ecosystem.Ecology, vol. 101, no. 1, Jan. 2020, p. e02897. Epmc, doi:10.1002/ecy.2897.
Morton JP, Silliman BR. Parasites enhance resistance to drought in a coastal ecosystem. Ecology. 2020 Jan;101(1):e02897.
Journal cover image

Published In

Ecology

DOI

EISSN

1939-9170

ISSN

1939-9170

Publication Date

January 2020

Volume

101

Issue

1

Start / End Page

e02897

Related Subject Headings

  • Wetlands
  • Poaceae
  • Parasites
  • North Carolina
  • Ecosystem
  • Ecology
  • Droughts
  • Animals
  • 4102 Ecological applications
  • 3109 Zoology