Demographic mechanisms of reef coral species winnowing from communities under increased environmental stress

Bernhard Riegl, Georgenes Cavalcante, Andrew G. Bauman, David A. Feary, Sascha Steiner, Sam Purkis

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Winnowing of poorly-adapted species from local communities causes shifts/declines in species richness, making ecosystems increasingly ecologically depauperate. Low diversity can be associated with marginality of environments, which is increasing as climate change impacts ecosystems globally. This paper demonstrates the demographic mechanisms (size-specific mortality, growth, fertility; and metapopulation connectivity) associated with population-level changes due to thermal stress extremes for five zooxanthellate reef-coral species. Effects vary among species, leading to predictable changes in population size and, consequently, community structure. The Persian/Arabian Gulf (PAG) is an ecologically marginal reef environment with a subset of Indo-Pacific species, plus endemics. Local heating correlates with changes in coral population dynamics and community structure. Recent population dynamics of PAG corals were quantified in two phases (medium disturbed MD 1998-2010 and 2013-2017, severely disturbed SD 1996/8, 2010/11/12) with two stable states of declining coral frequency and cover. The strongest changes in life-dynamics, as expressed by transition matrices solved for MD and SD periods were in Acropora downingi and Porites harrisoni, which showed significant partial and whole-colony mortality (termed "shrinkers"). But in Dipsastrea pallida, Platygyra daedalea, Cyphastraea microphthalma the changes to life dynamics were more subtle, with only partial tissue mortality (termed "persisters"). Metapopulation models suggested recovery predominantly in species experiencing partial rather than whole-colony mortality. Increased frequency of disturbance caused progressive reduction in coral size, cover, and population fecundity. Also, the greater the frequency of disturbance, the more larval connectivity is required to maintain the metapopulation. An oceanographic model revealed important local larval retention and connectivity primarily between adjacent populations, suggesting that correlated disturbances across populations will lead to winnowing of species due to colony, tissue, and fertility losses, with resultant insufficient dispersal potential to make up for losses-especially if disturbances increase under climate change. Variable extinction thresholds exist based on the susceptibility of species to disturbance ("shrinkers" vs. "persisters"), determining which species will be winnowed from the community. Besides projected changes in coral community and population structure, no species are projected to increase in cover. Increased marginality due to climate change will lead to a net loss of coral cover and novel communities in PAG.

Original languageEnglish (US)
Article number344
JournalFrontiers in Marine Science
Volume4
Issue numberOCT
DOIs
StatePublished - Oct 27 2017

Fingerprint

Reefs
environmental stress
Climate change
coral reefs
coral reef
corals
Population dynamics
demographic statistics
coral
Ecosystems
Persian Gulf
Tissue
disturbance
community structure
metapopulation
climate change
connectivity
Thermal stress
mortality
Daedalea

Keywords

  • Climate change
  • Connectivity
  • Coral reefs
  • Matrix model
  • Metapopulation
  • Oceanographic model
  • Persian/Arabian gulf
  • Population dynamics

ASJC Scopus subject areas

  • Oceanography
  • Global and Planetary Change
  • Aquatic Science
  • Water Science and Technology
  • Environmental Science (miscellaneous)
  • Ocean Engineering

Cite this

Demographic mechanisms of reef coral species winnowing from communities under increased environmental stress. / Riegl, Bernhard; Cavalcante, Georgenes; Bauman, Andrew G.; Feary, David A.; Steiner, Sascha; Purkis, Sam.

In: Frontiers in Marine Science, Vol. 4, No. OCT, 344, 27.10.2017.

Research output: Contribution to journalArticle

Riegl, Bernhard ; Cavalcante, Georgenes ; Bauman, Andrew G. ; Feary, David A. ; Steiner, Sascha ; Purkis, Sam. / Demographic mechanisms of reef coral species winnowing from communities under increased environmental stress. In: Frontiers in Marine Science. 2017 ; Vol. 4, No. OCT.
@article{3717be57ce244ae4910bd55a9a35a1b6,
title = "Demographic mechanisms of reef coral species winnowing from communities under increased environmental stress",
abstract = "Winnowing of poorly-adapted species from local communities causes shifts/declines in species richness, making ecosystems increasingly ecologically depauperate. Low diversity can be associated with marginality of environments, which is increasing as climate change impacts ecosystems globally. This paper demonstrates the demographic mechanisms (size-specific mortality, growth, fertility; and metapopulation connectivity) associated with population-level changes due to thermal stress extremes for five zooxanthellate reef-coral species. Effects vary among species, leading to predictable changes in population size and, consequently, community structure. The Persian/Arabian Gulf (PAG) is an ecologically marginal reef environment with a subset of Indo-Pacific species, plus endemics. Local heating correlates with changes in coral population dynamics and community structure. Recent population dynamics of PAG corals were quantified in two phases (medium disturbed MD 1998-2010 and 2013-2017, severely disturbed SD 1996/8, 2010/11/12) with two stable states of declining coral frequency and cover. The strongest changes in life-dynamics, as expressed by transition matrices solved for MD and SD periods were in Acropora downingi and Porites harrisoni, which showed significant partial and whole-colony mortality (termed {"}shrinkers{"}). But in Dipsastrea pallida, Platygyra daedalea, Cyphastraea microphthalma the changes to life dynamics were more subtle, with only partial tissue mortality (termed {"}persisters{"}). Metapopulation models suggested recovery predominantly in species experiencing partial rather than whole-colony mortality. Increased frequency of disturbance caused progressive reduction in coral size, cover, and population fecundity. Also, the greater the frequency of disturbance, the more larval connectivity is required to maintain the metapopulation. An oceanographic model revealed important local larval retention and connectivity primarily between adjacent populations, suggesting that correlated disturbances across populations will lead to winnowing of species due to colony, tissue, and fertility losses, with resultant insufficient dispersal potential to make up for losses-especially if disturbances increase under climate change. Variable extinction thresholds exist based on the susceptibility of species to disturbance ({"}shrinkers{"} vs. {"}persisters{"}), determining which species will be winnowed from the community. Besides projected changes in coral community and population structure, no species are projected to increase in cover. Increased marginality due to climate change will lead to a net loss of coral cover and novel communities in PAG.",
keywords = "Climate change, Connectivity, Coral reefs, Matrix model, Metapopulation, Oceanographic model, Persian/Arabian gulf, Population dynamics",
author = "Bernhard Riegl and Georgenes Cavalcante and Bauman, {Andrew G.} and Feary, {David A.} and Sascha Steiner and Sam Purkis",
year = "2017",
month = "10",
day = "27",
doi = "10.3389/fmars.2017.00344",
language = "English (US)",
volume = "4",
journal = "Frontiers in Marine Science",
issn = "2296-7745",
publisher = "Frontiers Media S. A.",
number = "OCT",

}

TY - JOUR

T1 - Demographic mechanisms of reef coral species winnowing from communities under increased environmental stress

AU - Riegl, Bernhard

AU - Cavalcante, Georgenes

AU - Bauman, Andrew G.

AU - Feary, David A.

AU - Steiner, Sascha

AU - Purkis, Sam

PY - 2017/10/27

Y1 - 2017/10/27

N2 - Winnowing of poorly-adapted species from local communities causes shifts/declines in species richness, making ecosystems increasingly ecologically depauperate. Low diversity can be associated with marginality of environments, which is increasing as climate change impacts ecosystems globally. This paper demonstrates the demographic mechanisms (size-specific mortality, growth, fertility; and metapopulation connectivity) associated with population-level changes due to thermal stress extremes for five zooxanthellate reef-coral species. Effects vary among species, leading to predictable changes in population size and, consequently, community structure. The Persian/Arabian Gulf (PAG) is an ecologically marginal reef environment with a subset of Indo-Pacific species, plus endemics. Local heating correlates with changes in coral population dynamics and community structure. Recent population dynamics of PAG corals were quantified in two phases (medium disturbed MD 1998-2010 and 2013-2017, severely disturbed SD 1996/8, 2010/11/12) with two stable states of declining coral frequency and cover. The strongest changes in life-dynamics, as expressed by transition matrices solved for MD and SD periods were in Acropora downingi and Porites harrisoni, which showed significant partial and whole-colony mortality (termed "shrinkers"). But in Dipsastrea pallida, Platygyra daedalea, Cyphastraea microphthalma the changes to life dynamics were more subtle, with only partial tissue mortality (termed "persisters"). Metapopulation models suggested recovery predominantly in species experiencing partial rather than whole-colony mortality. Increased frequency of disturbance caused progressive reduction in coral size, cover, and population fecundity. Also, the greater the frequency of disturbance, the more larval connectivity is required to maintain the metapopulation. An oceanographic model revealed important local larval retention and connectivity primarily between adjacent populations, suggesting that correlated disturbances across populations will lead to winnowing of species due to colony, tissue, and fertility losses, with resultant insufficient dispersal potential to make up for losses-especially if disturbances increase under climate change. Variable extinction thresholds exist based on the susceptibility of species to disturbance ("shrinkers" vs. "persisters"), determining which species will be winnowed from the community. Besides projected changes in coral community and population structure, no species are projected to increase in cover. Increased marginality due to climate change will lead to a net loss of coral cover and novel communities in PAG.

AB - Winnowing of poorly-adapted species from local communities causes shifts/declines in species richness, making ecosystems increasingly ecologically depauperate. Low diversity can be associated with marginality of environments, which is increasing as climate change impacts ecosystems globally. This paper demonstrates the demographic mechanisms (size-specific mortality, growth, fertility; and metapopulation connectivity) associated with population-level changes due to thermal stress extremes for five zooxanthellate reef-coral species. Effects vary among species, leading to predictable changes in population size and, consequently, community structure. The Persian/Arabian Gulf (PAG) is an ecologically marginal reef environment with a subset of Indo-Pacific species, plus endemics. Local heating correlates with changes in coral population dynamics and community structure. Recent population dynamics of PAG corals were quantified in two phases (medium disturbed MD 1998-2010 and 2013-2017, severely disturbed SD 1996/8, 2010/11/12) with two stable states of declining coral frequency and cover. The strongest changes in life-dynamics, as expressed by transition matrices solved for MD and SD periods were in Acropora downingi and Porites harrisoni, which showed significant partial and whole-colony mortality (termed "shrinkers"). But in Dipsastrea pallida, Platygyra daedalea, Cyphastraea microphthalma the changes to life dynamics were more subtle, with only partial tissue mortality (termed "persisters"). Metapopulation models suggested recovery predominantly in species experiencing partial rather than whole-colony mortality. Increased frequency of disturbance caused progressive reduction in coral size, cover, and population fecundity. Also, the greater the frequency of disturbance, the more larval connectivity is required to maintain the metapopulation. An oceanographic model revealed important local larval retention and connectivity primarily between adjacent populations, suggesting that correlated disturbances across populations will lead to winnowing of species due to colony, tissue, and fertility losses, with resultant insufficient dispersal potential to make up for losses-especially if disturbances increase under climate change. Variable extinction thresholds exist based on the susceptibility of species to disturbance ("shrinkers" vs. "persisters"), determining which species will be winnowed from the community. Besides projected changes in coral community and population structure, no species are projected to increase in cover. Increased marginality due to climate change will lead to a net loss of coral cover and novel communities in PAG.

KW - Climate change

KW - Connectivity

KW - Coral reefs

KW - Matrix model

KW - Metapopulation

KW - Oceanographic model

KW - Persian/Arabian gulf

KW - Population dynamics

UR - http://www.scopus.com/inward/record.url?scp=85032682177&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85032682177&partnerID=8YFLogxK

U2 - 10.3389/fmars.2017.00344

DO - 10.3389/fmars.2017.00344

M3 - Article

AN - SCOPUS:85032682177

VL - 4

JO - Frontiers in Marine Science

JF - Frontiers in Marine Science

SN - 2296-7745

IS - OCT

M1 - 344

ER -