The Williams Lab

Palaeo50: The Pressing Questions in Palaeoecology
Williams Lab Top 50 (or 80...) Questions

A workshop will be held 13-14 December 2012 at Oxford to discuss and identify the 50 most pressing questions in paleoecology. More information about the workshop can be found here, and you can follow the group on Twitter (@Palaeo50). Members of the Williams lab met over the course of several weeks to discuss our contributions to the list of questions. The questions below are the result: our contribution to the 50 Pressing Questions in Paleoecology workshop.

Palaeo50 Categories

Human-environment interactions
Ecology over long timescales
Conservation, novel ecosystems and ecological adaptation
Approaches to palaeoecology

The numbers in parentheses preceding each question indicate the mean and standard deviation of our scores, and the bolded questions are among our top 10. For the process we went through to come up with the questions, look here.

Human-environment interactions


1. (1.83; 0.41) How can paleoecology inform the shift from management baselines to management targets, in the context of a globally changing world and the prevalence of cultural landscapes?
2. (1.67; 0.52) How deterministic is ecological and climatic context on human subsistence strategies and sociocultural evolution?

Agriculture and Land Use

3. (2.33; 0.82) How do historical agricultural practices differ from modern ones, and what are the implications of these changes on the carbon cycle, biodiversity, and other ecosystem functions?
4. (2.83; 0.41) How did the land use footprint per capita change through the Quaternary, and how is it linked to demographic, social, and economic changes?
5. (2.5; 0.55) How much carbon dioxide and methane was released to the atmosphere as a result of early agricultural activity, and what impact did this have on Earth’s climate?


6. (2; 0.89) How has human use of fire changed as subsistence strategies evolved over the Quaternary?
7. (3; 0) What were the effects of anthropogenic fire on ecosystem composition and function?

Ecosystem Services

8. (1.67; 0.82) Which ecosystem function or services are measurable using paleoecological methods, and how can we expand this list?
9. (1.83; 0.98) How stable are ecosystem services over time?

Ecology over long timescales


10. (1.67; 0.82) How stable is ecosystem functioning within climate space or within biomes, given that species dynamics are individualistic and associations among species within biomes change over time?
11. (1.83; 0.98) What are the implications of species reshuffling on ecosystem function? Does species loss versus species gain have different effects on ecosystem function?
12. (2.33; 0.82) How does climate variability affect the evolution of species?
13. (2.5; 0.55) How do ecological interactions drive evolutionary change over short and long timescales?
14. (2.33; 0.52) What are the relative roles of stochastic vs deterministic controls on ecosystem development? How often do we misattribute deterministic processes to stochastic events?
15. (2; 0.89) Is landscape-scale heterogeneity in species distributions largely stable and controlled by topographic and edaphic properties, or is it changeable over time?


16. (2.83; 0.41) How fast can species migrate?
17. (2.5; 0.55) What is the role of long-distance dispersal events in pacing migration?
18. (2.5; 0.55) How can we better calculate rates of migration given the new knowledge of previously unknown refugia?
19. (2.5; 0.55) How important are refugia (and cryptic refugia) as sources of propagules for dispersal?
20. (2.17; 0.75) How important were now-extinct megafauna and frugivores as agents of dispersal?

Megafaunal Extinctions - Causes

21. (2.33; 0.52) Which species were unambiguously driven to extinction by climate change? By humans? What is the relative proportions of those instances and how does that change over space and time?
22. (2.67; 0.52) Why did some megafaunal species survive the late-Pleistocene extinctions and not others? What stochastic and deterministic processes determined survivorship?
23. (2; 0.89) What are the spatial and temporal patterns of megafaunal extinction within continents?
24. (2.17; 0.41) What was the structure and trends in megafaunal populations during the onset of the last interglacial, and how were these trends similar to or different from the trends (and extinctions) observed at the start of the Holocene interglacial?

Megafaunal Extinctions - Consequences

25. (2.67; 0.52) What were the ecological consequences of the Pleistocene megafaunal extinctions?
26. (2; 0.89) To what degree did the Pleistocene megafauna promote landscape openness in now-forested regions?
27. (2; 0.63) Did the loss of megafauna affect the abundance and distribution of other mammalian species via top-down trophic effects or via bottom-up changes in vegetation composition and structure?

Abrupt Change, Tipping Points, and Alternate Stable States

28. (2.83; 0.41) When we observe abrupt ecological changes in paleorecords, are these caused by abrupt climatic change, internal tipping points, and/or positive feedback loops between the ecosystem, atmosphere, and/or other external systems?
29. (2.5; 0.84) Why are some systems more resilient to environmental change than others?
30. (2.5; 0.55) How does rate of change in forcing affect resilience of ecological system to forcing?
31. (3; 0) Are ecological tipping points more associated with certain kinds of climatic change, e.g., with hydroclimatic variability as opposed to thermal variability?
32. (2.83; 0.41) Do early warning signal (EWS) methods work with paleoeroecords? Which work best?
33. (2.33; 0.82) How do the ecological consequences of a tipping point passed in one species or subcomponent of a system cascade to other species and other parts of a system?
34. (2.17; 0.41) Can we detect the signal of historical contingencies and path-dependence in paleoecological records?

Physiological Effects of Varying Atmospheric CO2

35. (1.5; 0.55) How has low CO2 shaped the competitive interactions between C3 and C4 plants and between trees and grasses?
36. (2; 0.89) Did low CO2 affect herbivores through effects on forage quality and quantity?
37. (2.5; 0.55) What were the interactive effects of CO2 and fire on plant community composition and function?
38. (2.67; 0.82) Are terrestrial ecosystem models appropriately sensitive to CO2 effects?

Carbon Cycling

39. (2.17; 0.75) What was the effect of centennial-scale climate variability (megadroughts, little ice age, medieval climate anomaly) on the carbon balance of ecosystems at regional to global scales?

Conservation, novel ecosystems and ecological adaptation

No-Analog Communities

40. (2.5; 0.55) What is the global distribution of no-analog species associations across multiple taxonomic groups in space and time?
41. (1.83; 0.98) How can we standardize our definitions of no-analog associations to be more comparable across ecological groups?
42. (2.33; 0.82) Does the occurrence of a no-analog assemblage in one taxonomic group lead to a higher likelihood of no-analog assemblages in other taxonomic groups?
43. (2.83; 0.41) Are past no-analog associations always associated with no-analog climates and the same sets of environmental factors?


44. (2.33; 0.52) Does similarity in the realized niches of contemporary species predict similarity in ecological responses to past climates, regardless of taxonomic groups?
45. (2.83; 0.41) Why are some species’ realized niches relatively plastic and others more stable? Is it because of evolved changes to the fundamental niche, because of shifting intersections between the realized climate space and the fundamental niche, and/or by shifting biotic interactions?
46. (2.17; 0.75) Does pooling species-climate datasets across time intervals improve our characterization of the fundamental niche and hence the predictive ability of species distribution models?
47. (1.83; 0.75) Which species or groups of species tend to have stable realized niches?
48. (1.83; 0.75) What do changes in the distribution of species during the Quaternary imply about the evolution of the fundamental and realized niches?

Species Associations and Species Interactions

49. (1.83; 0.98) How can we infer species interactions (process) from species associations (data)?
50. (2.5; 0.55) Why are some species associations more stable than others? Is this stability due to similar environmental niches, co-evolutionary relationships, or randomness?
51. (2.33; 0.82) Are across-trophic-level associations more stable than within-trophic-level questions?

Refugia and Biodiversity

52. (1.67; 0.52) How do source/sink dynamics within heterogeneous landscapes buffer against temporal climate variability?
53. (2.83; 0.41) How much does spatial environmental heterogeneity enable species persistence during periods of abrupt climate change?

Pleistocene Rewilding

54. (2; 0.89) Is the latest Pleistocene an appropriate baseline for contemporary conservation managment?

Approaches to palaeoecology


55. (2; 0.89) How does intensive local-scale sampling change our understanding of landscape-scale heterogeneity and ecological processes?
56. (1.5; 0.84) How do we formally define criteria for picking particular species for analysis?
57. (1.83; 0.41) How can we best integrate the fossil record, phylogeography, and knowledge of species life history to accurately model past and future species migration and response to environmental changes?

Biodiversity - Measuring

58. (2.33; 0.82) Are fossil data reliable indicators of biodiversity (e.g., species richness, functional richness, and community turnover) and how can we improve them?
59. (1.83; 0.98) How much of past biodiversity dynamics are we able to capture using the paleorecord?

Ancient DNA

60. (2.33; 0.52) How variable is the half-life of aDNA and how far back can we go with this proxy in different climatic and preservational contexts?
61. (2; 0.63) Can we move beyond current applications of aDNA to (phylogeographic and population demographic) to study adaptive responses of species to climate change?

Data-Model Assimilation

62. (2; 0.63) How can we best assimilate paleoecological data with mechanistic ecological models to provide insights about the past functioning of ecological systems?
63. (1.5; 0.84) Which data are most suited for assimilation and how should models be modified to assimilate data?
64. (2; 0.63) When assimilating paleoecological data with ecosystem models, where are the areas of greatest uncertainty?


65. (2.67; 0.52) What data standards and practices should we develop to promote the joint analysis and sharing of paleoecological data?

Paleoclimatic Inferences from Paleoecological Data

66. (2; 0.63) The climate signal extractable from fossil pollen records is caused by multiple ecological processes, operating at different timescales and sensitive to different climatic variables (e.g., interannual variability in pollen production, plant population dynamics). How can we best disentangle these signals and processes? (pollen-specific question)
67. (2.17; 0.98) The climate signal extractable from fossil records is caused by multiple ecological processes, operating at different timescales and sensitive to different climatic variables. How can we best disentangle these signals and processes? (generic version of prior question)

Questions from the Climate Refugia Workshop – Eugene Oregon – August 1-3 2012, hosted by Dan Gavin

68. (3; 0) What makes and maintains a refuge? And how do you locate them? Or identify where best to create new ones (ex situ conservation)?
69. (2.67; 0.52) What are the most important environmental controls (Tmin, AET, …) and how can we link them to the physiology of the species?
70. (2.17; 0.75) Is it severity of extreme events; the duration of unfavorable conditions that matters?
71. (1.83; 0.41) Is climate velocity a good metric for identifying refuges? Are there others? Which variables?
72. (2.5; 0.55) How can we use historical data to refine environmental niche models and their identification of 21st-century refuges? e.g., better parameterization, better incorporation of processes
73. (2.67; 0.52) How well do current patterns of diversity predict past (or future) refuges?
74. (1.83; 0.75) How important is species plasticity or adaptation for explaining past refugia?
75. (1.83; 0.75) Is the fitness of species consistently higher/lower in contemporary refuges compared to elsewhere in range?
76. (2.5; 0.84) How important are refuges for conserving genetic diversity? Do species with refuges/higher persistence in space have consistently higher genetic diversity than species with few refugia/low persistence?
77. (1.33; 0.52) How does fundamental niche and geographic range co-evolve across species?
78. (2.17; 0.75) How much does the number and position of refugia matter for post-refugia expansion dynamics and competition among species?
79. (2.17; 0.98) How much is extinction stochastic versus deterministic? How much does geography affect extinction risk?
80. (1.83; 0.75) Are background extinction rates in deeper-time records caused by climate variability vs spp. interactions?

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