Pollen in Laminated Sediments Provides Evidence For a Mid-Holocene Forest Pathogen Outbreak

Allison, Thomas C.; Moeller, R. P.; Davis, Margaret B.

doi:10.2307/1939835

Cited by 161 publications

(110 citation statements)

References 9 publications

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“…Alternatively, many entomologists suggest that the signature and duration of the hemlock decline is inconsistent with that of known insect impacts and more analogous to a fungal or viral pathogen (J. Elkinton, personal communication). This pathogenic interpretation has also been favored by other paleoecological studies (Allison et al 1986, Davis 1989.…”

Section: Introductionmentioning

confidence: 65%

A Climatic Driver for Abrupt Mid-Holocene Vegetation Dynamics and the Hemlock Decline in New England

Foster

Oswald

Faison

et al. 2006

Ecology

116

111

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Abstract. The mid-Holocene decline of eastern hemlock is widely viewed as the sole prehistorical example of an insect-or pathogen-mediated collapse of a North American tree species and has been extensively studied for insights into pest-host dynamics and the consequences to terrestrial and aquatic ecosystems of dominant-species removal. We report paleoecological evidence implicating climate as a major driver of this episode. Data drawn from sites across a gradient in hemlock abundance from dominant to absent demonstrate: a synchronous, dramatic decline in a contrasting taxon (oak); changes in lake sediments and aquatic taxa indicating low water levels; and one or more intervals of intense drought at regional to continental scales. These results, which accord well with emerging climate reconstructions, challenge the interpretation of a biotically driven hemlock decline and highlight the potential for climate change to generate major, abrupt dynamics in forest ecosystems.

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Section: Introductionmentioning

confidence: 65%

A Climatic Driver for Abrupt Mid-Holocene Vegetation Dynamics and the Hemlock Decline in New England

Foster

Oswald

Faison

et al. 2006

Ecology

116

111

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“…Plant macrofossil sequences show similar patterns (Anderson et al 1986, Jackson 1989, Spear et al 1994, Reeves 2006, confirming that the Tsuga decline represents a reduction in population size rather than pollen productivity. The decline at individual sites appears to have occurred in less than a century, possibly less than a decade (Allison et al 1986). …”

Section: Introductionmentioning

confidence: 99%

“…In an elegant application of ''strong inference'' (Chamberlin 1890, Platt 1964) to paleoecology, Davis argued that the event was caused by a pest or pathogen outbreak by evaluating and rejecting a series of alternative hypotheses and by drawing analogies to the 20th century pathogen-driven Castanea and Ulmus declines in the same region (Davis 1981, Allison et al 1986.…”

Section: Introductionmentioning

confidence: 99%

Decomposing the mid‐Holocene Tsuga decline in eastern North America

Booth

Brewer

Blaauw

et al. 2012

Ecology

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Abstract. The mid-Holocene decline of Tsuga canadensis (hereafter Tsuga) populations across eastern North America is widely perceived as a synchronous event, driven by pests/ pathogens, rapid climate change, or both. Pattern identification and causal attribution are hampered by low stratigraphic density of pollen-sampling and radiometric dates at most sites, and by absence of highly resolved, paired pollen and paleoclimate records from single sediment cores, where chronological order of climatic and vegetational changes can be assessed. We present an intensely sampled (contiguous 1-cm intervals) record of pollen and water table depth (inferred from testate amoebae) from a single core spanning the Tsuga decline at Irwin Smith Bog in Lower Michigan, with high-precision chronology. We also present an intensively sampled pollen record from Tower Lake in Upper Michigan. Both sites show high-magnitude fluctuations in Tsuga pollen percentages during the pre-decline maximum. The terminal decline is dated at both sites ca. 5000 cal yr BP, some 400 years later than estimates from other sites and data compilations. The terminal Tsuga decline was evidently heterochronous across its range. A transient decline ca. 5350 cal yr BP at both sites may correspond to the terminal decline at other sites in eastern North America. At Irwin Smith Bog, the terminal Tsuga decline preceded an abrupt and persistent decline in water table depths by ;200 years, suggesting the decline was not directly driven by abrupt climate change. The Tsuga decline may best be viewed as comprising at least three phases: a long-duration predecline maximum with high-magnitude and high-frequency fluctuations, followed by a terminal decline at individual sites, followed in turn by two millennia of persistently low Tsuga populations. These phases may not be causally linked, and may represent dynamics taking place at multiple temporal and spatial scales. Further progress toward understanding the phenomenon requires an expanded network of high-resolution pollen and paleoclimate chronologies.

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“…Response model for characterising resilience in timeseries, including an assessment of (1) disturbance regime, including pulse and press perturbations, (2) the ecosystem or proxy response, such as recovery rate and regime shift, and (3) an evaluation of causal relationships. The resolution and proxies may determine which definition or resilience and therefore which analytical methods are most appropriate at each of these stages 13 (Allison et al 1986, Peglar 1993; causal explanations rely on high-resolution analysis of laminated sediments or recent sediments with secure chronological controls to demonstrate the comparability of past and recent events Informal hypothetical approach: qualitative comparison of competing explanations using multiple timeseries or sources of evidence, e.g. for climate, human activity (Davis 1981, Parker et al 2002 Quantitative hypothesis-testing using modelling: GLMM used to compare pollen and catchment (erosion and nutrient availability) responses during endemic and outbreak phases Multiple proxies: inferences rely on multiple lines of evidence to identify outbreaks , Waller 2013, and to test potential interacting or alternative mechanisms, including climate variability as a trigger for pest or pathogen outbreaks (Latalowa et al 2013), and human activity facilitating pathogen dispersal and impacts (Parker et al 2002) Gillson & Ekblom 2009, McLauchlan et al 2014, Jeffers et al 2015.…”

Section: Defining Resiliencementioning

confidence: 99%

The application of resilience concepts in palaeoecology

et al. 2018

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The concept of resilience has become increasingly important in ecological and socioecological literature. With its focus on the temporal behaviour of ecosystems, palaeoecology has an important role to play in developing a scientific understanding of ecological resilience. We provide a critical review of the ways in which resilience is being addressed by palaeoecologists. We review ~180 papers, identifying the definitions or conceptualisations of 'resilience' that they use, and analysing the ways in which palaeoecology is contributing to our understanding of ecological resilience. We identify three key areas for further development. Firstly, the term 'resilience' is frequently defined too broadly to be meaningful without further qualification. In particular, palaeoecologists need to distinguish between 'press' vs. 'pulse' disturbances, and 'ecological' vs. 'engineering' resilience. Palaeoecologists are well placed to critically assess the extent to which these dichotomies apply in real (rather than theoretical) ecosystems, where climate and other environmental parameters are constantly changing. Secondly, defining a formal 'response model' -a statement of the anticipated relationships between proxies, disturbances and resilience properties -can help to clarify arguments, especially inferred causal links, since the difficulty of proving causation is a fundamental limitation of palaeoecology for understanding ecosystem drivers and responses. Thirdly, there is a need for critical analysis of the role of scale in ecosystem resilience. Different palaeoenvironmental proxies are differently able to address the various temporal and spatial scales of ecological change, and these limitations, as well as methodological constraints on inherently noisy proxy data, need to be explored and addressed.

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Pollen in Laminated Sediments Provides Evidence For a Mid-Holocene Forest Pathogen Outbreak

Cited by 161 publications

References 9 publications

A Climatic Driver for Abrupt Mid-Holocene Vegetation Dynamics and the Hemlock Decline in New England

A Climatic Driver for Abrupt Mid-Holocene Vegetation Dynamics and the Hemlock Decline in New England

Decomposing the mid‐Holocene Tsuga decline in eastern North America

The application of resilience concepts in palaeoecology

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