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Abstract Increases in the frequency and intensity of acute and chronic disturbances are causing declines of coral reefs world‐wide. Although quantifying the responses of corals to acute disturbances is well documented, detecting subtle responses of coral populations to chronic disturbances is less common, but can also result in altered population and community structures.We investigated the population dynamics of two key reef‐building Merulinid coral species,Dipsastraea favusandPlatygyra lamellina, with similar life‐history traits, in the Gulf of Eilat and Aqaba, Red Sea from 2015 to 2018, to assess potential differences in their population trajectories.Demographic processes, which included rates of survival, growth, reproduction and recruitment were used to parametrize integral projection models and estimate population growth rates and the likely population trajectories of both coral species.The survival and reproduction rates of bothD. favusandP. lamellinawere positively related to coral colony size, and elasticity analyses showed that large colonies most influenced population dynamics. Although both species have similar life‐history traits and growth morphologies and are generally regarded as ‘stress‐tolerant’, the populations showed contrasting trajectories—D. favusappears to be increasing whereasP. lamellinaappears to be decreasing.As many corals have long‐life expectancies, the process of local and regional decline might be subtle and slow. Ecological assessments based on total living coral coverage, morphological groups or functional traits might overlook subtle, species‐specific trends. However, demographic approaches capable of detecting subtle species‐specific population changes can augment ecological studies and provide valuable early warning signs of decline before major coral loss becomes evident.
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Net effects of life‐history traits explain persistent differences in abundance among similar species
Abstract Life‐history traits are promising tools to predict species commonness and rarity because they influence a population's fitness in a given environment. Yet, species with similar traits can have vastly different abundances, challenging the prospect of robust trait‐based predictions. Using long‐term demographic monitoring, we show that coral populations with similar morphological and life‐history traits show persistent (decade‐long) differences in abundance. Morphological groups predicted species positions along two, well known life‐history axes (the fast‐slow continuum and size‐specific fecundity). However, integral projection models revealed that density‐independent population growth (λ) was more variable within morphological groups, and was consistently higher in dominant species relative to rare species. Within‐group λ differences projected large abundance differences among similar species in short timeframes, and were generated by small but compounding variation in growth, survival, and reproduction. Our study shows that easily measured morphological traits predict demographic strategies, yet small life‐history differences can accumulate into large differences in λ and abundance among similar species. Quantifying the net effects of multiple traits on population dynamics is therefore essential to anticipate species commonness and rarity.
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- Award ID(s):
- 1948946
- PAR ID:
- 10540019
- Publisher / Repository:
- Ecological Society of America
- Date Published:
- Journal Name:
- Ecology
- Volume:
- 104
- Issue:
- 1
- ISSN:
- 0012-9658
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1002/ecy.3863
