Taphonomic Dynamics of Lacustrine Ostracodes on San Salvador Island, Bahamas: High Fidelity and Evidence of Anthropogenic Modification

Michelson, Andrew V.; Park, Lisa E.

doi:10.2110/palo.2012.p12-031r

Cited by 17 publications

(13 citation statements)

References 46 publications

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“…Ferguson (), for example, found that molluscan DAs in Florida Bay could detect, with high spatial resolution and within a few years, the ecological impact of a small artificial line‐source of nutrients, which favoured one type of seagrass over another. At a coarser spatial scale, Casey and Dietl () found a gradient in molluscan live‐dead rank‐abundance agreement consistent with a known gradient of anthropogenic eutrophication within the relatively urban Long Island Sound (taxonomic similarity does not vary), and Michelson and Park (), evaluating ostracod assemblages in seven saline lakes from Bahamas, encountered poor live‐dead agreement only in the lake with a known history of human use (plantation, penning of sea turtles). Focusing on raptor‐concentrated small‐mammal assemblages, Terry () encountered significantly poorer live‐dead agreement in richness, evenness, taxonomic similarity and species rank‐abundance in a steppe landscape with strong recent human disturbance (military training, invasive cheatgrass) than in a relatively undisturbed counterpart (Fig.…”

Section: Recognizing Anthropogenic Changementioning

confidence: 82%

Time‐averaging and fidelity of modern death assemblages: building a taphonomic foundation for conservation palaeobiology

2013

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Ecosystems today are under growing pressure, with human domination at many scales. It is difficult, however, to gauge what has changed or been lost -and why -in the absence of data from periods before human activities. Actualistic taphonomic studies, originally motivated to understand preservational controls on deep-time fossil records, are now providing insights into modern death assemblages as historical archives of present-day ecosystems, turning taphonomy on its head. This article reviews the past 20 years of work on the temporal resolution and ability of time-averaged skeletal assemblages to capture ecological information faithfully, focusing primarily on molluscs from soft-sediment seafloors. Two promising arenas for 'applied taphonomy' are then highlighted: (1) using live-dead mismatch -that is, observed discordance in the diversity, species composition, and distribution of living animals and cooccurring skeletal remains -to recognize recent anthropogenic change, and (2) using time-averaged death assemblages as windows into regional diversity and long-term baselines, as a supplement or substitute for conventional live-collected data. Meta-analysis and modelling find that, in unaltered habitats, live-dead differences in community-level attributes can be generated largely or entirely by time-averaging of natural spatial and temporal variability in living assemblages, on time frames consistent with the range of shell ages observed in death assemblages. Time-averaging coarsens the temporal and spatial resolution of biological information in predictable ways; by comparison, taphonomic bias of information arising from differential preservation, production and transport of shells is surprisingly modest. Several challenges remain for basic taphonomic research, such as empirical and analytical methods of refining the temporal resolution of death assemblages; assessing the fate of resolution and fidelity with progressive burial; and expanding our understanding of the dynamics of skeletal accumulation in other groups and settings. Rather than shunning human-impacted areas as inappropriate analogues of the deep past, we should capitalize on them to explore the fundamental controls on skeletal accumulation and to develop robust protocols for bringing time-averaged death assemblages into the toolkits of conservation biology and environmental management.

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Section: Recognizing Anthropogenic Changementioning

confidence: 82%

Time‐averaging and fidelity of modern death assemblages: building a taphonomic foundation for conservation palaeobiology

2013

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“…[For an early case study recognizing the importance of time averaging rather than postmortem transportation and other processes in creating observed live-dead differences, see Warme (1969).] Comparably good live-dead agreement is being found in other groups, such as ungulate and other "large-mammal" assemblages (see review by Behrensmeyer & Miller 2012); small-mammal assemblages (e.g., Jorgensen et al 1998;Hadly 1999;Reed 2007;Terry 2010a,b); freshwater and terrestrial mollusks (e.g., Rundell & Cowie 2004, Erthal et al 2011, Tietze & De Francesco 2012, Yanes 2012; lake ostracodes (Michelson & Park 2013); and, for some diversity attributes, reef corals (see review by Greenstein 2007) and hard-substratum mollusks (e.g., Zuschin et al 2000, Zuschin & Stachowitsch 2007, Albano & Sabelli 2011. This high level of fidelity is not expected for all groups, particularly ones with strong interspecies differences in body size and other features affecting intrinsic durability (e.g., all birds as opposed to passerines) (Behrensmeyer et al 2003, Turvey & Blackburn 2011; for a general discussion, also see Kidwell 2013).…”

Section: Temporal Scaling: Observed Effects In Death Assemblagesmentioning

confidence: 82%

Implications of Time-Averaged Death Assemblages for Ecology and Conservation Biology

Kidwell

Tomášových

2013

Annu. Rev. Ecol. Evol. Syst.

143

110

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Biologists increasingly appreciate the importance of community-level attributes in the functioning and temporal turnover of ecosystems, but data other than species richness are difficult to acquire over the habitat-toregional and decadal-to-millennial scales needed to recognize biodiversity change, discriminate between natural and anthropogenic drivers, and inform theoretical and applied ecology. Death assemblages (DAs)-the actively accumulating organic remains encountered in present-day seabeds and landscapes, as distinct from permanently buried fossil assemblages-are an underexploited source of historical information at precisely these scales. Meta-analyses, dynamic modeling, and individual case studies, particularly of mollusks and mammals, reveal that DAs differ from censused living assemblages (LAs) primarily because they are temporally coarse, time-averaged samples, contrary to concerns that postmortem bias dominates. Temporal pooling predictably damps the ability of DAs to detect small-scale variation, but promotes their ability to inventory rare species; estimate the abundance structure of the metacommunity; document range changes; evaluate historic habitat use; and identify now-absent species, community states, and anthropogenically shifted baselines. 539 Annu. Rev. Ecol. Evol. Syst. 2013.44:539-563. Downloaded from www.annualreviews.org by 178.253.154.35 on 12/18/13. For personal use only.

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“…Except for one lake, Watling's Blue Hole, live/dead agreement in rank-abundance and taxonomic composition was extremely high (Michelson and Park, 2013). Likewise, except for Watling's, little or no variability was found among death assemblages in these lakes (Michelson and Park, 2013). Thus, the ostracodes in the death assemblages collected by net sweeping were determined to represent "modern" assemblages, typical of the lakes from which they were sampled.…”

Section: Field and Laboratory Methodsmentioning

confidence: 97%

“…Lacustrine ostracode species live benthic or nekton-benthic lifestyles and are sensitive to changes in the abiotic environment such as salinity, water depth, temperature, or dissolved oxygen concentration (Frenzel and Boomer, 2005). Their low-Mg calcite shells can be preserved as fossils and commonly range in size from 0.5-2 mm and long have been used as biological proxies of anthropogenic change and past environmental conditions (Frenzel and Boomer 2005;Padmanabha and Belagali, 2008;Michelson and Park, 2013). These organisms have already been used in transfer functions (see Viehberg and Mesquita-Joanes, 2012 for a review) in lake sediments to reconstruct conductivity (Mezquita et al, 2005;Mischke et al, 2007;Mischke et al, 2010a;Mischke et al, 2014;Mercau and Laprida, 2016), water depth (Mourguiart and Carbonel, 1994;Mourguiart et al, 1998;Alin and Cohen, 2003;Mischke et al, 2010b;Peng et al, 2013;Guo et al, 2016), and temperature (Mezquita et al, 2005;Viehberg, 2006).…”

Section: Introductionmentioning

confidence: 99%

A quantitative inference model for conductivity using non-marine ostracode assemblages on San Salvador Island, Bahamas: Paleosalinity records from two lakes

Michelson

Boush

2017

Palaeogeography, Palaeoclimatology, Palaeoecology

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Quantitative records of past environments are needed to understand natural variability in ecosystems and their responses to climate change. Changes in ostracode assemblages through time can provide such records as ostracode species are sensitive to changes in their local environments. Before they can be used to indicate past environments, however, is it necessary to understand how distributions of assemblages change across environmental gradients. To that end, thirty-two lakes on San Salvador Island, Bahamas were sampled for both ostracodes and nineteen limnological variables. Multivariate fuzzy set ordination indicates that change in ostracode assemblages is significantly and independently correlated with three environmental variables: electrical conductivity (salinity), dissolved oxygen and alkalinity. A transfer function was created to reconstruct past conductivity since changing conductivity of lakes on San Salvador is influenced by changes in climate and sea-level. A 2-component weighted-averaging partial least squares model performed best as a transfer function for conductivity with an apparent r 2 of 0.76 and an r 2 of 0.69 between observed and predicted conductivity, as assessed by leave-one-out cross validation. The resulting transfer function was then applied to two mid-to late-Holocene sediment cores from which ostracode assemblages were sampled. The late Holocene conductivity records show that changes in conductivity of lakes on San Salvador are broadly synchronous with times of enhanced ENSO activity corresponding to elevated conductivity in response to lower Atlantic hurricane occurrence. These results demonstrate that changing ostracode assemblages through time provide a reliable means to reconstruct past salinity and demonstrates the strong effect of ENSO on Bahamian aridity. This study 92

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Taphonomic Dynamics of Lacustrine Ostracodes on San Salvador Island, Bahamas: High Fidelity and Evidence of Anthropogenic Modification

Cited by 17 publications

References 46 publications

Time‐averaging and fidelity of modern death assemblages: building a taphonomic foundation for conservation palaeobiology

Time‐averaging and fidelity of modern death assemblages: building a taphonomic foundation for conservation palaeobiology

Implications of Time-Averaged Death Assemblages for Ecology and Conservation Biology

A quantitative inference model for conductivity using non-marine ostracode assemblages on San Salvador Island, Bahamas: Paleosalinity records from two lakes

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