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

09:05-09:30 Testing the effects of multi-stressor global change in deep time

Professor Matthew Clapham, UC Santa Cruz, USA

Abstract

The oceans are being transformed as temperature, pH, and oxygen content all change at rates unprecedented in the recent geological past, but predicting vulnerability to these stressors remains a challenge. However, similar events of rapid climate change have occurred repeatedly in Earth’s deep time past. As a result, the fossil record provides opportunities to test hypothesized effects of climate change on the marine biosphere. For example, are more active organisms less vulnerable to climate change stressors? Are tropical organisms at greater risk of extinction, or does environmental variability influence survival? Can direct physiological stresses from temperature be reconstructed at the level of an individual organism? The nature of the fossil record limits the types of questions that can be asked, but its record of biotic change over evolutionary timescales and at global scales provides a complementary perspective that is difficult to obtain from experiments or observations on the extant biota. Extinction patterns in the fossil record help constrain the mechanisms through which climate change disrupts the biosphere and provide clues that reveal, at a broad scale, the groups that may be especially vulnerable during the coming decades.

09:30-09:45 Discussion

09:45-10:15 A conservation paleobiological perspective on Chesapeake Bay oysters

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 demographic declines and extinctions

Professor Love Dalén, Swedish Museum of Natural History, Sweden

Abstract

Recent developments in DNA extraction and sequencing methods have revolutionized our ability to recover genetic information from ancient bones and teeth, thus making it possible to generate data on mutation rates as well as temporal changes in genomic diversity, inbreeding levels, gene frequencies and population size. In particular, such ancient DNA studies have enabled detailed reconstructions of the timing, rate and extent of demographic declines, and to what extent these these coincided with past environmental fluctuations, such as changes in climate and sea levels. Moreover, whole genome sequences from serially sampled ancient specimens now make it possible to investigate to what extent environmentally driven demographic declines led to inbreeding and accumulation of deleterious genetic variants.

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 species extinction dynamics

Associate 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 and Aarhus University, Denmark

Abstract

Humans have driven biodiversity loss and modified ecosystem structure for millennia. Using modern ecological data therefore has the risk of considerably affecting our understanding of ecological patterns of “natural” species distributions and of the dynamics and drivers of past extinctions. This bias ultimately narrows our perception of the options available for conservation and the potential for species’ recovery. Long-term archives are often perceived as unsuitable for ecological analyses because of the substantial levels of bias and error they may contain. However, by extending the timeline usually considered in ecology, they can provide unique new insights into extinction dynamics and changing species distribution through time and represent a unique opportunity to better inform regional environmental management. Assessment and utilization of long-term archives thus represent both a methodological challenge and an important conservation research priority. Here, we integrate fossil, historical and modern occurrence records of large mammals in Southern Africa from the Holocene to the present and explore the challenges and opportunities associated with using long-term biodiversity data in ecological analyses. We present some limitations of fossil and historical records and highlight the importance of considering these long-term archives to estimate species’ historical distribution and natural habitat requirements. We evidence local extinctions and changes in community composition, consistent with a response to the demographic expansion of European colonists in South Africa. These results contribute to novel baselines for conservation and provide a strengthened evidence-base for understanding long-term faunal responses to human pressures. It also allows the “shifted baselines” around modern mammal distributions to be identified, providing an avenue for new analyses of large mammal biogeographic patterns in Southern Africa.

09:30-09:45 Discussion

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

Dr Jennifer Crees, Natural History Museum, UK

Abstract

Long-term data are vital for tracking changes in biodiversity through time. The Holocene contains a rich fossil record of global biodiversity for the last 11,700 years to the present day. It is therefore considered a particularly robust data source for researching dynamics and drivers of species extinction, and for informing our understanding of the current extinction crisis. However, as with all fossil datasets it nonetheless suffers from incompleteness and bias. Without knowledge of the extent of these biases we risk making false inferences, which in turn limit the use of this data for conservation. Patterns of bias and/or incompleteness were investigated in two Holocene fossil data sets collected at different spatiotemporal scales. Firstly, factors associated with the description date of 256 extinct mammals were analysed in order to assess bias in our knowledge of global, species-level mammal extinctions. Secondly, sources of bias were identified in a dataset of nearly 20,000 fossil mammal records used to reconstruct population-level range change and extinction. A number of biases were found in both datasets, with the Holocene fossil record general biased towards the discovery and description of larger-bodied mammals in continental regions, compared with smaller-bodied mammals in insular regions. The implications of these results in shaping our understanding of past biodiversity loss and our ability to use the Holocene fossil record in conservation-related research are discussed.

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

Professor 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 drop-off 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 Trophic rewilding – background, opportunities and challenges for megafauna-based restoration in the Anthropocene

Professor Jens-Christian Svenning, Aarhus University, Denmark

Abstract

Most current real-world ventures named as rewilding fall under the concept of trophic rewilding, as do most discussion of rewilding. Trophic rewilding is an ecological restoration strategy that uses species introductions to restore top-down trophic interactions and associated trophic cascades to promote self-regulating biodiverse ecosystems (http://bit.ly/rewildingPNAS). Trophic rewilding is often focused on large-bodied animals (both herbivores and carnivores) due to their ecological and societal importance and the widespread, strong historical and recent prehistorical losses of megafauna in most regions around the world. In this presentation, I will first discuss the concept of trophic rewilding, and then outline the scientific background for trophic rewilding, integrating paleoecology and contemporary ecology. Key themes here will the fact that megafauna-rich ecosystems have been the norm on evolutionary timescales, with the widespread modern-day megafauna-poor ecosystems being a novel situation, and the emerging evidence for the strong ecological importance of large-bodied animals. I will also discuss the current role of trophic rewilding in nature conservation and ecological restoration as well as its potential, now and in the future. Linked to this, I will also discuss tricky issues such as base-lines, relations to other land uses, perceived risks to people and ecosystems, and the use of exotic species in rewilding. Finally, I will outline key priorities and possibilities for this research field.

14:00-14:15 Discussion

14:15-14:45 Unshifting the baseline: integrating ancient human impacts into indicators of biodiversity change

Dr Ana Rodrigues, National Centre for Scientific Research, France

Abstract

Ancient human impacts to ecosystems are often underestimated because such changes took place gradually and left little recorded evidence. This translates into distorted perceptions of what natural ecosystems correspond to – i.e., into shifted ecological baselines – that have pervasive effects on management and conservation decisions. For example, biodiversity indicators built from recent data on species’ distributions, population sizes and trends – such as the Red List Index and the Living Planet Index – underestimate the extent of human impacts and may translate into unambitious conservation goals and recovery targets. It is however not straightforward to obtain biodiversity indicators that take into account ancient impacts, given the incompleteness of the historical record. Furthermore, variations in the timeline of impacts across species and regions mean that there is not a single appropriate baseline date that is applicable to all. This presentation will introduce a new approach for assessing populations according to the extent to which they have been impacted by past human activities. It will illustrate its application to large whale species, to show how such assessments can be applied consistently across species with very different impact histories and with wide variations in the depth of available historical data, by making the best use of the information available in each case. Multi-species assessments can then be aggregated into temporal and spatial indices of biodiversity that are less prone to the shifting baseline syndrome.

14:45-15:00 Discussion

15:00-15:30 Tea

15:30-16:00 Using knowledge of the past to set conservation goals in the present

Dr Molly Grace, University of Oxford, UK

Abstract

The most widely-used global metric of species conservation status today is the IUCN Red List of Threatened Species, which assesses species’ extinction risk. The timescales over which changes in species status are evaluated must necessarily be relatively short (10 years or 3 generations, depending on the species) in order to highlight rapid declines in population size or range which may signal acute threats to species persistence. However, this relatively narrow temporal focus presents a danger of shifting baselines, since declines which have occurred in previous centuries often do not fall within the relevant time window for assessment.

This talk outlines the opportunities and difficulties in using historical data (accounts, museum records, zooarchaeological and fossil records, etc.) to inform Red List assessments and also introduces the IUCN’s response to the challenge of shifting baselines: The Green List of Species. The Green List of Species, currently in development, will be used to measure species recovery against a baseline set centuries ago, rather than decades. The Green List will allow long-term ambitions to restore species to historical levels to work in parallel with the crucial short-term focus on preventing extinction, providing a more comprehensive conservation story that includes a species’ past, present, and potential future.

16:00-16:15 Discussion

16:15-17:00 Panel discussion/overview (future directions)