Explaining high-diversity death assemblages : Undersampling of the living community, out-of-habitat transport, time-averaging of rare taxa, and local extinction
Bürkli, Anja LU
and Wilson, Anthony B.
(2017)
In Palaeogeography, Palaeoclimatology, Palaeoecology
466.
p.174-183
- Abstract
Molluscan benthic assemblages provide unique opportunities for understanding both spatial and temporal patterns of biodiversity. Species richness in the shell remains found at a site (i.e. the death assemblage) is typically several times higher than in the counterpart living assemblage, reflecting a complex history of settlement, dissemination and decomposition post-mortem. We used high-density temporal and spatial sampling (> 37000 individuals representing 196 taxa) of a shallow (5–8 m) nearshore sandy habitat off the coast of south-east Sardinia (Italy, Mediterranean Sea) to study the factors responsible for differences in the relative diversity of living and death assemblages. We found that death assemblages at all sites were... (More)
Molluscan benthic assemblages provide unique opportunities for understanding both spatial and temporal patterns of biodiversity. Species richness in the shell remains found at a site (i.e. the death assemblage) is typically several times higher than in the counterpart living assemblage, reflecting a complex history of settlement, dissemination and decomposition post-mortem. We used high-density temporal and spatial sampling (> 37000 individuals representing 196 taxa) of a shallow (5–8 m) nearshore sandy habitat off the coast of south-east Sardinia (Italy, Mediterranean Sea) to study the factors responsible for differences in the relative diversity of living and death assemblages. We found that death assemblages at all sites were considerably more diverse than living communities (1.5–3.5x more dead than living taxa after sample-size standardization), with 78% of all taxa solely recovered as empty shells, resulting in low live-dead agreement. By carefully filtering the raw data and combining them with habitat information extracted from the literature, we disentangled the major causes of this discordance and quantified their individual effects. Increased dead diversities could not be attributed to undersampling of the living community, but instead resulted from three phenomena of decreasing importance: the post-mortem, out-of-habitat transport of non-indigenous taxa (57% of dead-only taxa were allochthonous), the time-averaged presence of rare indigenous taxa (40% of dead-only taxa), and the likely local extirpation of a small number of species (3% of dead-only taxa). Our approach demonstrates how ecological inferences based on death assemblages can be improved by restricting analyses to demonstrably indigenous taxa, and highlights how mollusc shell remains can be used to provide information over both ecological and evolutionary timescales.
(Less)
- author
- Bürkli, Anja
LU
and Wilson, Anthony B.
- publishing date
- 2017-01-15
- type
- Contribution to journal
- publication status
- published
- keywords
- Allochthonous species, Benthic ecology, Biodiversity, Living community, Mollusca, Taphonomy
- in
- Palaeogeography, Palaeoclimatology, Palaeoecology
- volume
- 466
- pages
- 10 pages
- publisher
- Elsevier
- external identifiers
-
- scopus:84997254268
- ISSN
- 0031-0182
- DOI
- 10.1016/j.palaeo.2016.11.022
- language
- English
- LU publication?
- no
- additional info
- Funding Information: We thank the editor, an anonymous reviewer and especially Susan Kidwell for the helpful comments on earlier versions of this manuscript. Heinz Maag, Rolf Schärer, Seraina Tgetgel Halawa and Sarah Wolf helped in collecting and sorting the census samples. Markus Huber and Werner Huber provided assistance with taxonomic identifications, and Erik Postma assisted with statistical analyses. Funding for this research was provided by the University of Zurich . Publisher Copyright: © 2016 Elsevier B.V.
- id
- 4a048576-695a-4736-978f-9d2fbf01858e
- date added to LUP
- 2023-12-11 11:23:26
- date last changed
- 2023-12-15 16:42:01
@article{4a048576-695a-4736-978f-9d2fbf01858e,
abstract = {{<p>Molluscan benthic assemblages provide unique opportunities for understanding both spatial and temporal patterns of biodiversity. Species richness in the shell remains found at a site (i.e. the death assemblage) is typically several times higher than in the counterpart living assemblage, reflecting a complex history of settlement, dissemination and decomposition post-mortem. We used high-density temporal and spatial sampling (> 37000 individuals representing 196 taxa) of a shallow (5–8 m) nearshore sandy habitat off the coast of south-east Sardinia (Italy, Mediterranean Sea) to study the factors responsible for differences in the relative diversity of living and death assemblages. We found that death assemblages at all sites were considerably more diverse than living communities (1.5–3.5x more dead than living taxa after sample-size standardization), with 78% of all taxa solely recovered as empty shells, resulting in low live-dead agreement. By carefully filtering the raw data and combining them with habitat information extracted from the literature, we disentangled the major causes of this discordance and quantified their individual effects. Increased dead diversities could not be attributed to undersampling of the living community, but instead resulted from three phenomena of decreasing importance: the post-mortem, out-of-habitat transport of non-indigenous taxa (57% of dead-only taxa were allochthonous), the time-averaged presence of rare indigenous taxa (40% of dead-only taxa), and the likely local extirpation of a small number of species (3% of dead-only taxa). Our approach demonstrates how ecological inferences based on death assemblages can be improved by restricting analyses to demonstrably indigenous taxa, and highlights how mollusc shell remains can be used to provide information over both ecological and evolutionary timescales.</p>}},
author = {{Bürkli, Anja and Wilson, Anthony B.}},
issn = {{0031-0182}},
keywords = {{Allochthonous species; Benthic ecology; Biodiversity; Living community; Mollusca; Taphonomy}},
language = {{eng}},
month = {{01}},
pages = {{174--183}},
publisher = {{Elsevier}},
series = {{Palaeogeography, Palaeoclimatology, Palaeoecology}},
title = {{Explaining high-diversity death assemblages : Undersampling of the living community, out-of-habitat transport, time-averaging of rare taxa, and local extinction}},
url = {{http://dx.doi.org/10.1016/j.palaeo.2016.11.022}},
doi = {{10.1016/j.palaeo.2016.11.022}},
volume = {{466}},
year = {{2017}},
}