The past is a foreign country: how much can the fossil record actually inform conservation?

09:00-09:05 Welcome by the Royal Society and lead organiser

09:30-09:35 Discussion

09:45-10:15 Models for recovery of life after biotic crises

Professor Rowan Lockwood, College of William & Mary, USA

Abstract

The eastern oyster (Crassostrea virginica) plays a vital role in Chesapeake Bay habitats, acting as an ecosystem engineer and improving water quality via filtration. Populations of bay oysters have declined precipitously in recent decades, primarily due to human harvesting and disease. By the time oyster monitoring was established in the 1940s, reefs were already decimated, suggesting that scientists have never actually observed a healthy reef in the Chesapeake Bay. The fossil record, which preserves 500,000 years of once-thriving reefs, provides a unique opportunity to study pristine reefs and a possible baseline for oyster mitigation.

For this study, over 4000 fossil oysters were examined from 11 Pleistocene localities in the mid-Atlantic US. Data on oyster shell lengths, lifespans, growth rates, and population density were assessed relative to data from modern oyster monitoring surveys, in addition to archeological and historical sources. Comparisons to modern C. virginica, sampled from similar environmental conditions, reveal that fossil oysters were significantly larger, longer-lived, and an order of magnitude more abundant than modern oysters. This pattern results from the preferential harvesting of larger, reproductively more active females from the modern population.

These fossil data, when combined with modern estimates of age-based fecundity and mortality, make it possible to estimate biological function in these long-dead reefs, including carbonate production and filtering capacity. Conservation paleobiology can provide us with a picture of what the Chesapeake Bay looked like, but also how it functioned before humans.

10:15-10:30 Discussion

10:30-11:00 Coffee

11:00-11:30 Marine ecosystem responses to temperature-related stressors through time

Professor Wolfgang Kiessling, Friedrich-Alexander-University of Erlangen-Nürnberg, Germany

Abstract

We know that current climate change is already affecting biological systems at global scale, and temperature-related stressors (TRS) are often invoked to explain ecosystem changes in deep time. Without the direct anthropogenic stressors complicating responses, we can (1) potentially better isolate the impact of TRS in the past than today and (2) see under which circumstances TRS lead to ecosystem collapse or mass extinctions. There are many complicating issues such as the vastness of geological time, implying large uncertainties about rates of change, the scarcity of non-skeletal organisms in fossil ecosystems, and different players, which perhaps did things differently in the past. However, simulations and new analytical approaches may help reveal time-invariant principles.

Insights from past responses to TRS may then allow going beyond current approaches in conservation paleobiology and predict the fate of ecosystems under increasing TRS. For example, tropical reef systems have always collapsed under acute global warming rather than cooling and traits of reef corals are significantly linked to their extinction risk. Focussing on marine systems, Kiessling will first summarise the lessons we have already learnt from the past and then provide some guidelines towards a better integration of palaeobiological knowledge in conservation biology.

11:30-11:45 Discussion

11:45-12:15 Are “living fossil” taxa likely to contribute to future evolutionary potential?

Dr Dominic Bennett, University of Gothenberg, Sweden

Abstract

Are evolutionary distinct species – what may fancifully be called “living fossils” – more or less likely to diversify in the future? The various forms of evidence and argumentation for how evolutionary distinctness may be a predictor of evolutionary potential are mixed. Depending on the scientific discipline and the data, these taxa may either be doomed to extinction or primed for future diversification. With an increasing focus of conservation effort towards the evolutionary distinct, such a question is of growing importance. If it is shown that these “living fossils” have higher rates of extinction and lower rates of speciation, then it may be argued that time and resources should not be spent on these evolutionary dead-ends. Conversely, if these groups can be identified as evolutionary fuses then it may be argued that their conservation is key to safeguarding future biodiversity. Here we map the fates of mammalian clades through time to their evolutionary distinctnesses. We find that taxa that are evolutionary distinct have increasing measures of evolutionary distinctness through time. This indicates that these groups have lower rates of speciation but also lower rates of extinction and, as such, represent neither dead-ends nor fuses. Our finding recasts the conservation arguments: protecting the evolutionary distinct will not secure the future of life; it will, however, not be a wasted effort either.

12:15-12:30 Discussion

13:30-14:00 Biogeochemical constraints on primary production: Evidence from the Late Quaternary

Dr Elizabeth Jeffers, University of Oxford, UK

Abstract

The terrestrial carbon sink has absorbed one third of the anthropogenic carbon dioxide (CO2) emitted since the start of the Industrial Revolution, primarily through increased primary production. Nitrogen (N) availability constrains primary productivity in many temperate and boreal ecosystems, yet the extent to which N might limit the ability of terrestrial ecosystems to sequester current and future CO2 emissions remains uncertain. In order to predict future terrestrial carbon storage capacity and to identify which ecosystems are most likely to store carbon without N limitation, we need to know where N limitation occurs, over what time scale, and how this is affected by ecological and environmental contexts. Palaeoecological data provide important evidence needed to determine long-term plant-N interactions and how these vary under different climatic and biotic contexts. I will describe how statistical modelling techniques have been used to infer centennial-scale N limitation of plant biomass dynamics from fossil pollen and stable N isotope data from Late Quaternary sedimentary sequences, as well as current and future work that will help identify the factors underpinning N limitation in modern terrestrial ecosystems.

14:00-14:15 Discussion

14:15-14:45 Using ancient DNA to understand population responses to past environmental change

Professor Love Dalén, Swedish Museum of Natural History, Sweden

14:45-15:00 Discussion

15:00-15:30 Tea

15:30-16:00 All is flux: the predictive power of fluctuating Quaternary faunal-climate scenarios

Professor Danielle Schreve, Royal Holloway University of London, UK

Abstract

The long-term impact of Middle and Late Pleistocene glacial-interglacial change led to the major reorganisation of mammalian faunal communities in northern Europe through species origination, extinction, evolutionary change and distributional shifts. However, it is clear that the particular climatic and environmental parameters of each interglacial resulted in the generation of very different faunal assemblages in terms of composition and diversity, depending on the length and stability of the interglacial, the rapidity of climatic warming and the changing nature of physical barriers and competitors. Nevertheless, despite the relatively coarse temporal resolution of the record over much of the last half million years, the overall ‘predictability’ of interglacial community composition is arguably better than for the Last Glacial-Interglacial transition, when extreme and abrupt climatic changes resulted in spectacularly rapid aggregations of species that are frequently referred to as ‘disharmonious’, by comparison to their present day biogeography. Using evidence from north-west European interglacial records, combined with new archives based on British cave sequences, the presentation will examine the reasons for the contrast in structure between warm and cold stage faunas and evaluate the capacity of mammalian taxa to withstand abrupt climate change during the terminal Pleistocene.

16:00-16:15 Discussion

16:15-16:45 Incorporating Quaternary baselines into macroecological analysis of assemblage dynamics across space and time

Assistant Professor Jessica Blois, UC Merced, USA

Abstract

Climate influences the structure of both mammal and plant assemblages across space and time, seen most clearly in the emergence of novel mammal and plant assemblages coincident with novel climates during the late Quaternary. The past therefore implies that novel assemblages should be expected for the future given the rate and magnitude of projected future climate change. Prior work, however, has typically examined the relationship between Quaternary climate and biodiversity in mammals and vegetation separately, without consideration of how these two groups are influenced by one another. Including both mammals and vegetation in ecological models of the influence of climate on assemblages may be necessary to capture a fuller set of processes influencing spatiotemporal changes in species distributions and community structure. Together, these two issues – novel climates and narrow taxonomic focus – may influence the reliability of inferences from ecological forecasts through time and especially into the novel climates expected for the future. This talk uses late Quaternary fossil pollen and mammal data from the Neotoma Paleoecology Database to explore the reliability of ecological forecasts through time and examine whether including cross-trophic associations, in addition to climate, as predictors in community-level models improved the ability to capture and model meaningful ecological variation across space and time.

16:45-17:00 Discussion

09:00-09:30 Identifying ecological baselines for terrestrial megafauna using long-term biodiversity data: a South African case study

Dr Sophie Monsarrat, Nelson Mandela University, South Africa

Abstract

Using modern ecological data to reconstruct past biodiversity baselines has the risk of considerably affecting our understanding of ecological patterns of “natural” species distributions and abundance and of the dynamics and drivers of past extinctions. This bias ultimately narrows our perception of the options available for conservation. By extending the timeline usually considered in ecology, long-term archives can provide novel insights into changing species distributions through time and represent a unique opportunity to better inform regional environmental management. We assembled modern, historical and fossil occurrence records for medium- to large-sized terrestrial mammals in Southern Africa to reconstruct the timing and dynamics of regional extinction events for the Southern African megafauna. We evidence local extinctions and changes in community composition since the early historical period. The biogeography of species diversity loss is consistent with a response to the demographic expansion of European colonists spreading from the south-western part of South Africa, with larger mammals being the most impacted. These results contribute to novel baselines for conservation and provide a strengthened evidence-base for understanding long-term faunal responses to human pressures. These findings also allow the “shifted baselines” around modern mammal distributions to be identified, providing an avenue for new analyses of large mammal biogeographic patterns for this region.

09:30-09:45 Discussion

09:45-10:15 Bias, incompleteness, and the “known unknowns” of the Quaternary fossil record

Dr Jennifer Crees, Natural History Museum, UK

10:15-10:30 Discussion

10:30-11:00 Coffee

11:00-11:30 Complementarity, resolution and quality of long-term archives for Asia, the world’s top conservation hotspot

Dr Samuel Turvey, Institute of Zoology, Zoological Society of London, UK

Abstract

Understanding past environmental baselines and the extent that human activities have already affected species and ecosystems is crucially important for today’s “conservation hotspots”, which contain disproportionate amounts of threatened biodiversity. It is necessary to evaluate the unique information content of different long-term archives, and determine what novel insights are available on past ecosystem structure and change, in order to understand how past baselines can inform current conservation research and management. Eastern and Southeast Asia contain the world’s highest numbers of threatened vertebrates and plants, and the region has a long history and prehistory of human occupation. Within this region, China (a huge, ‘megadiverse’ country) possesses diverse ecological archives including a millennial-scale historical record and rich Late Quaternary palaeontological and zooarchaeological records. By integrating and analysing a series of complementary, temporally non-overlapping archives (fossils, a ~400-year gazetteer record, and ethnic minority group oral traditions and local knowledge), the history of a regional Chinese mammal fauna is reconstructed across the Holocene, revealing that Hainan Island has experienced an ‘extinction filter’ associated with protracted, ongoing depletion of large mammal diversity over recent millennia, rather than recent ecological collapse of a faunally intact system. However, China’s Quaternary faunal archives are all incomplete and biased in their information content on key ecological parameters, and differ from each other in their representativeness of past diversity. Whereas palaeontological, zooarchaeological and historical records are an invaluable resource for reconstructing pre-human environments and biodiversity loss through time, interpreting and extrapolating what they show therefore requires both caution and context.

11:30-11:45 Discussion

11:45-12:15 Using the Past to Better Prepare for a Novel Future: Building Open Paleodata to Improve Ecological Forecasting

Professor John Jack Williams, University of Madison-Wisconsin, USA

Abstract

Conservation biologists face a daunting challenge: conserving biological diversity and services during a carbon release event potentially as big as the Paleocene-Eocene Thermal Maximum, rises in global mean temperatures to Pliocene-like levels, at rates as fast or faster than those during the abrupt events of the last glacial period and deglaciation, and with hydrological extreme events likely to be as or more severe than those of the Holocene. The emergence of novel 21st-century climate rates and states challenges the predictive ability of ecological forecasting models; hindcasting tests against benchmark fossil records from the last deglaciation show a steep dropoff in predictive ability as climatic novelty increases. Improved ecological forecasting, however, can be achieved by the close integration of predictive models with neo- and paleoecological observations encompassing a broad range of timescales, processes, and system states. Advances in data-model assimilation are particularly promising and require a tight and iterative coupling between data and models. This in turn requires the assembly of paleoecological data into open data systems and with data quality improved on an on-going basis by expert curation, new data generation, and synthesis. Such efforts can also indicate key areas of model uncertainty that can be the target of new data-gathering campaigns.

12:15-12:30 Discussion

13:30-14:00 Rewilding the Late Quaternary – how realistic or desirable is this?

Professor Jens-Christian Svenning, Aarhus University, Denmark

14:00-14:15 Discussion

14:45-15:00 Discussion

15:00-15:30 Tea

16:00-16:15 Discussion

16:15-17:00 Panel discussion and future directions