Preservation of community structure in death assemblages of deep-water Caribbean reef corals

This paper assesses the reliability with which fossil reefs record the diversity and community structure of adjacent Recent reefs. The diversity and taxonomic composition of Holocene raised fossil reefs was compared with those of modern reef coral life and death assemblages in adjacent moderate and low-energy shallow reef habitats of Madang Lagoon, Papua New Guinea. Species richness per sample area and Shannon-Wiener diversity (H′) were highest in the fossil reefs, intermediate in the life assemblages, and lowest in the death assemblages. The taxonomic composition of the fossil reefs was most similar to the combination of the life and death assemblages from the modern reefs adjacent to the two fossil reefs. Depth zonation was recorded accurately in the fossil reefs. The Madang fossil reefs represent time-averaged composites of the combined life and death assemblages as they existed at the time the reef was uplifted.Because fossil reefs include overlapping cohorts from the life and death assemblages, lagoonal facies of fossil reefs are dominated by the dominant sediment-producing taxa, which are not necessarily the most abundant in the life assemblage. Rare or slow-growing taxa accumulate more slowly than the encasing sediments and are underrepresented in fossil reef lagoons. Time-averaging dilutes the contribution of rare taxa, rather than concentrating their contribution. Consequently, fidelity indices developed for mollusks in sediments yield low values in coral reef death and fossil assemblages. Branching corals dominate lagoonal facies of fossil reefs because they are abundant, they grow and produce sediment rapidly, and most of the sediment they produce is not exported.Fossil reefs distinguished kilometer-scale variations in community structure more clearly than did the modern life assemblages. This difference implies that fossil reefs may provide a better long-term record of community structure than modern reefs. This difference also suggests that modern kilometer-scale variation in coral reef community structure may have been reduced by anthropogenic degradation, even in the relatively unimpacted reefs of Madang Lagoon. Holocene and Pleistocene fossil reefs provide a time-integrated historical record of community composition and may be used as long-term benchmarks for comparison with modern, degraded, nearshore reefs. Comparisons between fossil reefs and degraded modern reefs display gross changes in community structure more effectively than they demonstrate local extinction of rare taxa.

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Preservation of spatial and environmental gradients by death assemblages

Paleobiology ◽

10.1666/07081.1 ◽

2009 ◽

Vol 35 (1) ◽

pp. 119-145 ◽

Cited By ~ 37

Author(s):

Adam Tomašových ◽

Susan M. Kidwell

Keyword(s):

Community Structure ◽

Community Composition ◽

Environmental Gradients ◽

Compositional Variation ◽

Time Averaging ◽

Data Sets ◽

Square Root ◽

Spatial Gradients ◽

Death Assemblages ◽

The Impact

Although only a few studies have explicitly evaluated live-dead agreement of species and community responses to environmental and spatial gradients, paleoecological analyses implicitly assume that death assemblages capture these gradients accurately. We use nine data sets from modern, relatively undisturbed coastal study areas to evaluate how the response of living molluscan assemblages to environmental gradients (water depth and seafloor type; “environmental component” of a gradient) and geographic separation (“spatial component”) is captured by their death assemblages. We find that:1. Living assemblages vary in composition either in response to environmental gradients alone (consistent with a species-sorting model) or in response to a combination of environmental and spatial gradients (mass-effect model). None of the living assemblages support the neutral model (or the patch-dynamic model), in which variation in species abundance is related to the spatial configuration of stations alone. These findings also support assumptions that mollusk species consistently differ in responses to environmental gradients, and suggest that in the absence of postmortem bias, environmental gradients might be accurately captured by variation in species composition among death assemblages. Death assemblages do in fact respond uniquely to environmental gradients, and show a stronger response when abundances are square-root transformed to downplay the impact of numerically abundant species and increase the effect of rare species.2. Species' niche positions (position of maximum abundance) along bathymetric and sedimentary gradients in death assemblages show significantly positive rank correlations to species positions in living assemblages in seven of nine data sets (both square-root-transformed and presence-absence data).3. The proportion of compositional variation explained by environmental gradients in death assemblages is similar to that of counterpart living assemblages. Death assemblages thus show the same ability to capture environmental gradients as do living assemblages. In some instances compositional dissimilarities in death assemblages show higher rank correlation with spatial distances than with environmental gradients, but spatial structure in community composition is mainly driven by spatially structured environmental gradients.4. Death assemblages correctly identify the dominance of niche metacommunity models in mollusk communities, as revealed by counterpart living assemblages. This analysis of the environmental resolution of death assemblages thus supports fine-scale niche and paleoenvironmental analyses using molluscan fossil records. In spite of taphonomic processes and time-averaging effects that modify community composition, death assemblages largely capture the response of living communities to environmental gradients, partly because of redundancy in community structure that is inherently associated with multispecies assemblages. The molluscan data sets show some degree of redundancy as evidenced by the presence of at least two mutually exclusive subsets of species that replicate the community structure, and simple simulations show that between-sample relationships can be preserved and remain significant even when a large proportion of species is randomly removed from data sets.

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Community structure and dynamics of deep-water decapod assemblages from Le Danois Bank (Cantabrian Sea, NE Atlantic): Influence of environmental variables and food availability

Progress In Oceanography ◽

10.1016/j.pocean.2007.09.003 ◽

2007 ◽

Vol 75 (4) ◽

pp. 797-816 ◽

Cited By ~ 31

Author(s):

Joan E. Cartes ◽

Alberto Serrano ◽

Francisco Velasco ◽

Santiago Parra ◽

Francisco Sánchez

Keyword(s):

Community Structure ◽

Food Availability ◽

Deep Water ◽

Environmental Variables ◽

Ne Atlantic ◽

Structure And Dynamics

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Sexual reproduction by the Caribbean reef corals Montastrea annularis and M. cavernosa

Marine Ecology Progress Series ◽

10.3354/meps074013 ◽

1991 ◽

Vol 74 ◽

pp. 13-25 ◽

Cited By ~ 80

Author(s):

AM Szmant

Keyword(s):

Sexual Reproduction ◽

Reef Corals ◽

Caribbean Reef ◽

Montastrea Annularis ◽

The Caribbean

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Sexual reproduction by the Caribbean reef corals Montastrea annularis and M. cavernosa

Marine Ecology Progress Series ◽

10.3354/meps075013 ◽

1991 ◽

Vol 75 ◽

pp. 13-25

Author(s):

AM Szmant

Keyword(s):

Sexual Reproduction ◽

Reef Corals ◽

Caribbean Reef ◽

Montastrea Annularis ◽

The Caribbean

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Eocene Caribbean reef corals: a unique fauna from the Gatuncillo Formation of Panama

Journal of Paleontology ◽

10.1017/s0022336000024446 ◽

1992 ◽

Vol 66 (4) ◽

pp. 570-594 ◽

Cited By ~ 28

Author(s):

Ann F. Budd ◽

Thomas A. Stemann ◽

Robert H. Stewart

Keyword(s):

Reef Coral ◽

Upper Eocene ◽

Generic Level ◽

Reef Corals ◽

Caribbean Reef ◽

The Family ◽

Generic Composition ◽

History Of ◽

The Caribbean ◽

Central Panama

Forty-three species of 25 genera are described in a collection of 170 large, massive reef corals from the upper Eocene Gatuncillo Formation near Lago Alahuela in central Panama. Comparisons with type material for other Eocene Caribbean reef corals suggest that 27 of these species are new. Twenty-four of these species are named herein. Like other Eocene Caribbean reef-coral faunas, the fauna is rich in Astrocoenia, Actinacis, and Astreopora; however, unlike other faunas, plocoid and meandroid members of the family Faviidae (e.g., Montastraea, Agathiphyllia, Goniastrea, and Colpophyllia) are abundant. Also present are the oldest known representatives of the genera Meandrina, Coscinaraea, Alveopora, Heliopora, and Pocillopora, as well as the only recorded occurrences of Coscinaraea and Cyathoseris from the Caribbean. Comparisons with Oligocene and Recent Caribbean reef-coral faunas suggest that the generic composition of Cenozoic Caribbean reefs became established during the Eocene. With exception of the family Mussidae, much of the post-Oligocene history of the Caribbean is one of extinction at the generic level (19 of the 28 Eocene genera became extinct) and proliferation of species within the surviving genera.

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Stratigraphic distributions of genera and species of Neogene to Recent Caribbean reef corals

Journal of Paleontology ◽

10.1017/s0022336000026585 ◽

1994 ◽

Vol 68 (5) ◽

pp. 951-977 ◽

Cited By ~ 92

Author(s):

Ann F. Budd ◽

Thomas A. Stemann ◽

Kenneth G. Johnson

Keyword(s):

Late Miocene ◽

Species Recognition ◽

Reef Coral ◽

Early Pleistocene ◽

Caribbean Region ◽

Acropora Palmata ◽

Free Living ◽

Reef Corals ◽

Caribbean Reef ◽

The Caribbean

To document evolutionary patterns in late Cenozoic Caribbean reef corals, we compiled composite stratigraphic ranges of 49 genera and 175 species using Neogene occurrences in the Cibao Valley sequence of the northern Dominican Republic and faunal lists for 24 Miocene to Recent sites across the Caribbean region. This new compilation benefits in particular from increased sampling at late Miocene to early Pleistocene sites and from increased resolution and greater taxonomic consistency provided by the use of morphometric procedures in species recognition.Preliminary examination and quantitative analysis of origination and extinction patterns suggest that a major episode of turnover took place between 4 and 1 Ma during Plio-Pleistocene time. During the episode, extinctions were approximately simultaneous in species of all reef-building families, except the Mussidae. Most strongly affected were the Pocilloporidae (Stylophora and Pocillopora), Agariciidae (Pavona and Gardineroseris), and free-living members of the Faviidae and Meandrinidae. At the genus level, mono- and paucispecific as well as more speciose genera became regionally extinct. Many of the extinct genera live today in the Indo-Pacific region, and some are important components of modern eastern Pacific reefs. Global extinctions were concentrated in free-living genera. During the turnover episode, no new genera or higher taxa arose. Instead, new species originated within the surviving Caribbean genera at approximately the same time as the extinctions, including many dominant modern Caribbean reef-building corals (e.g., Acropora palmata and the Montastraea annularis complex).Excluding this episode, the taxonomic composition of the Caribbean reef-coral fauna remained relatively unchanged during the Neogene. Minor exceptions include: 1) high originations in the Agariciidae and free-living corals during late Miocene time; and 2) regional or global extinctions of several important Oligocene Caribbean reef builders during early to middle Miocene time.

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