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The importance of an underestimated grazer under climate change: how crab density, consumer competition, and physical stress affect salt marsh resilience.

Publication ,  Journal Article
Angelini, C; van Montfrans, SG; Hensel, MJS; He, Q; Silliman, BR
Published in: Oecologia
May 2018

Climate change and consumer outbreaks are driving ecosystem collapse worldwide. Although much research has demonstrated that these factors can interact, how heterogeneity in top-down control intensity and physical forcing modulates ecosystem resilience to climate stress remains poorly understood. Here, we explore whether the nocturnal herbivorous crab Sesarma reticulatum can control spatially dominant cordgrass (Spartina alterniflora) growth and how its top-down effects vary with crab density, drought stress, and large-scale disturbance in southeastern US salt marshes. In multiple field experiments and surveys, we show that Sesarma depresses cordgrass growth and that its effects increase in a saturating manner with increasing crab density, such that the highest naturally occurring densities of this consumer can trigger local cordgrass die-off. This top-down effect of Sesarma is similar in magnitude to what is thought to be the dominant grazer in the system, the marsh periwinkle snail Littoraria irrorata. In a drought stress by Sesarma density experiment, we further show that salinity stress and intensive crab herbivory additively suppress cordgrass drought resistance. After drought subsides, surveys and experiments reveal that Sesarma also stifles cordgrass re-growth into existing die-off areas. Together, these results show that multiple grazers powerfully regulate the productivity and drought resilience of these intertidal grasslands and that heterogeneity in physical stress and consumer density can dictate when and where top-down forcing is important. More generally, this work provides a rare, experimental demonstration of the critical role top-down control can play across the initiation and recovery stages of ecosystem die-off.

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Published In

Oecologia

DOI

EISSN

1432-1939

ISSN

0029-8549

Publication Date

May 2018

Volume

187

Issue

1

Start / End Page

205 / 217

Related Subject Headings

  • Wetlands
  • Poaceae
  • Ecosystem
  • Ecology
  • Climate Change
  • Brachyura
  • Animals
  • 3109 Zoology
  • 3104 Evolutionary biology
  • 3103 Ecology
 

Citation

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Angelini, C., van Montfrans, S. G., Hensel, M. J. S., He, Q., & Silliman, B. R. (2018). The importance of an underestimated grazer under climate change: how crab density, consumer competition, and physical stress affect salt marsh resilience. Oecologia, 187(1), 205–217. https://doi.org/10.1007/s00442-018-4112-8
Angelini, Christine, Schuyler G. van Montfrans, Marc J. S. Hensel, Qiang He, and Brian R. Silliman. “The importance of an underestimated grazer under climate change: how crab density, consumer competition, and physical stress affect salt marsh resilience.Oecologia 187, no. 1 (May 2018): 205–17. https://doi.org/10.1007/s00442-018-4112-8.
Angelini, Christine, et al. “The importance of an underestimated grazer under climate change: how crab density, consumer competition, and physical stress affect salt marsh resilience.Oecologia, vol. 187, no. 1, May 2018, pp. 205–17. Epmc, doi:10.1007/s00442-018-4112-8.
Journal cover image

Published In

Oecologia

DOI

EISSN

1432-1939

ISSN

0029-8549

Publication Date

May 2018

Volume

187

Issue

1

Start / End Page

205 / 217

Related Subject Headings

  • Wetlands
  • Poaceae
  • Ecosystem
  • Ecology
  • Climate Change
  • Brachyura
  • Animals
  • 3109 Zoology
  • 3104 Evolutionary biology
  • 3103 Ecology