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Cambridge Prisms: Extinction is bringing together leading experts in the field to discuss the latest research, trends, and innovations in extinction. Our webinars will cover a range of topics, from diversity loss to mass extinction or population processes. We aim to provide a platform for knowledge exchange to enhance collaboration among researchers and policymakers. Join us for engaging discussions, interactive Q&A sessions, and opportunities to connect with peers and thought leaders in the field!
For a full list of upcoming webinars, please visit our seminar page here.
Speaker: Prof. Julien Louys
Date: 11th of July 2024
Event: Please find a link to the event here.
Scope: This presentation will explore the Pleistocene and Holocene extinction records along the routes of ancient and modern human migrations to Australia. Beginning with Homo erectus and their arrival in Southeast Asia, I will describe efforts to model their movements through the region and the impacts, if any, that they may have had on mammalian megafauna. Also key to this story is the extinction of this and other hominins during the mid to late Pleistocene. Hominins such as Homo luzonensis and Homo floresiensis were endemic island species whose demise may match other insular extinction records. The record of Homo sapiens movements through Wallacea begins shortly after these losses, but significant impacts on biotas by modern humans only seem to coincide with the Neolithic and the suite of behavioural and technological advances observed throughout the region. Finally, I will describe new efforts to address the megafaunal data deficit in Australia, through targeted excavations of new types of deposits.
Speaker: Prof. Richard Ladle
Date: 13th of June 2024
Event: Please find a link to the event here.
Scope: Predicting whether a species is likely to go extinct (or not) is one of the fundamental objectives of conservation biology, and extinction risk classifications have become an essential tool for conservation policy, planning and research. This sort of prediction is feasible because the extinction processes follow a familiar pattern of population decline, range collapse and fragmentation, and, finally, extirpation of sub-populations through a combination of genetic, demographic and environmental stochasticity. Though less well understood and rarely quantified, the way in which science and society respond to population decline, extirpation and species extinction can also have a profound influence, either negative or positive, on whether a species goes extinct. For example, species that are highly sought after by collectors and hobbyists can become more desirable and valuable as they become rarer, leading to increased demand and greater incentives for illegal trade – known as the anthropogenic Allee effect. Conversely, species that are strongly linked to cultural identity are more likely to benefit from sustainable management, high public support for conservation actions and fund-raising, and, by extension, may be partially safeguarded from extinction. More generally, human responses to impending extinctions are extremely complex, are highly dependent on cultural and socioeconomic context, and have typically been far less studied than the ecological and genetic aspects of extinction. In this seminar I identify and discuss biocultural aspects of extinction and outline how recent advances in our ability to measure and monitor cultural trends with big data are, despite their intrinsic limitations and biases, providing new opportunities for incorporating biocultural factors into extinction risk assessment.
Speaker: Assoc. Prof Diana Fisher
Date: 16th of May 2024
Event: Please find a link to the recording here.
Scope: The diverse and distinctive Australasian marsupial fauna has experienced considerable loss over the last 200 years. Seventeen of the 176 Australian marsupial species have become extinct in this period (~10%), far higher than the global average (1.4%). Many extinct Australian marsupials were formerly abundant and widespread. About 40% of Australian marsupials are now threatened. The pattern of decline in Australian marsupials is broadly similar to that of Australia’s native rodents- invasive mammalian predators and land use that facilitates them are the major problems.
Knowledge of the marsupial faunas of Papua New Guinea and Indonesia is relatively poor. Both regions have high endemism. There are 96 species of marsupials on the main island of New Guinea and surrounding small islands, and 15 species in Wallacea (the islands of Indonesia and East Timor east of Wallace’s line) including five shared with New Guinea. Although none are listed as Extinct, two Critically Endangered marsupials are flagged “possibly extinct.” Most threatened New Guinean and Wallacean species follow the globally typical pattern of high vulnerability in island endemics and small-range mammals with specialist habitats. The major threats to marsupials of New Guinea and Indonesia are habitat loss, hunting, and low levels of awareness and investment in conservation and research. Many Australasian marsupial species – particularly mountain-top endemics are increasingly threatened by climate change.
Speaker: Prof. Alice Hughes
Date: 25th of April 2024
Event: Please find a link to the recording here.
Scope: Globally we are beginning to realise the need for policies built on evidence, and for environmental policy that entails science-based policy. Yet, any analysis is only as good as the data used to conduct it, thus understanding the limitations and assumptions in environmental data is crucial to ensuring it’s sensible and effective use.
The digital revolution has seemingly changed the problem for many ecologists trying to understand the natural world from having insufficient data to approach many ecological questions, to one of how to usefully analyse ever growing volumes of data. Yet despite this huge volume of data, natural biases within the data require caution to ensure their sensible use, as those biases shape the outcomes of our analysis and may misrepresent true ecological patterns as a consequence. We also explore how different modes of data collection and the impact of citizen science in shaping our understanding of species patterns and how it may actually exacerbate rather than ameliorate existing biases.
However guiding sensible use and providing more robust solutions is key, thus building from this we provide recommendations to help guide sensible and effective use and interpretation of data, frameworks to enable more effective use of data within its sensible limits, and better approaches for the generation of further data to aid the development of effective conservation, policy and management. We also demonstrate how data can be sensitively analysed and applied to help create better and more sensitive environmental targets, and can also help align, such as ecological conservation redline policy and to maximise the synergies between climate and biodiversity targets.
Speaker: Dr Kate Lyons
Date: 18th of April 2024
Recording: Please find a link to the recording here.
Scope: Ecologists have long been interested in how species assemble into communities. In particular, they are interested in how species traits, environmental factors, and biotic interactions affect species distributions, and membership and persistence in ecological communities. Determining whether assembly rules exist and what they are is particularly important in the face of ongoing climate change. However, despite decades of study, no clear consensus has emerged. In part because modern studies are limited by the short time scales over which they are able to collect data and by the fact that humans are incredibly successful ecosystem engineers who have affected almost every part of the planet. In contrast, paleontologists have been interested in the interplay between species traits and the environment, and how these relationships change over time in response to global forcing factors such as climate change. Increased knowledge of taphonomic processes has led to an understanding that fossil assemblages preserve reliable information about ecological communities and species interactions. By comparing the structure of these fossil assemblages with modern assemblages, we can begin to identify aspects of community structure that are similar across many taxonomic groups and across long time scales. We can also determine whether and how these patterns have changed with the increasing dominance of humans on the globe. Using a macroecological lens, I examine mammalian community structure over long and short time scales including metrics such as co-occurrence structure, body size distributions, and functional traits. I evaluate how these patterns change over time and with changes in global climate. Finally, I examine how some traits associated with extinction risk have changed over time and the consequences for ecological communities. I find that in paleoecological communities, there are consistent patterns over time in terms of co-occurrence structure, body size distributions, and extinction risk, but that many of these patterns change as human impacts increase including the role that functional traits play in mediating co-occurrence structure. These changes suggest that humans are fundamentally altering ecological communities and resetting ecological assembly rules. Paleontology has a key role to play in identifying the disruptions to assembly rules by humans and what that means for predicting how species are likely to respond to future climate change, habitat fragmentation and the loss of biotic interactions because of extinctions.
Speaker: Prof Jonathan Payne
Date: 21st of March 2024
Recording: Please find a recording of the event here.
Scope: The end-Permian mass extinction, which occurred approximately 252 million years ago, was the most severe biodiversity crisis in the history of animal life. In the marine fossil record, about half of known animal families and 80% of genera were lost. Heavily calcified taxa with limited development of respiratory and circulatory systems are disproportionately represented among the victims. The geological record of the extinction interval contains chemical evidence, some based on newly developed proxies, of rapid global warming, ocean acidification, and ocean deoxygenation. High-precision age dating shows that eruption of the Siberian Traps large igneous province occurred during the extinction interval, providing a plausible mechanism for rapid and extreme environmental change. Earth system models can now replicate the environmental changes indicated by chemical proxies and the habitat space available to marine animals can be represented in these models based on a ratio of oxygen supply to metabolic demand. The model representation of biological response to global change predicts the observed gradient in extinction intensity from equator to pole, suggesting that temperature-induced hypoxia was a major direct cause of population collapse. Parallels between end-Permian and Anthropocene environmental changes can enable calibration of models designed to predict responses of the marine biosphere to environmental change anticipated over the next few centuries.
Speaker: Dr Wolfgang Kiessling
Date: 7th of March 2024
Recording: Please find a recording of the event here.
Scope: Coral reefs are under increasing pressure from direct human impacts and human-induced climate change. Reef corals are also thought to be at elevated extinction risk but estimates vary profoundly among studies. Works that use lost reef area as a proxy of coral population reduction tend to estimate high extinction risk, whereas approaches using estimates of coral population sizes advocate low extinction risk. The fossil record contributes to this discussion that (i) reef corals have low intrinsic extinction risk, (ii) the loss of reef area is a poor predictor of coral extinction rates, and (iii) reef coral extinction pulses were usually triggered by episodes of profound global warming. Taken together, the deep-time observations support that the current reef crisis is unlikely be develop into a coral mass extinction in the next century of so. In addition, the Red List categorization of reef coral conservation status does not align well with empirical extinctions of the near-time past.
Speaker: Prof. Michał Kowalewski
Date: 15th of February 2024
Recording: Please find a recording of the event here.
Scope: Predation is not only one of the key ecological process shaping modern ecosystems, but may have also played an important role throughout the evolutionary history of animals. However, assessing biotic interactions in the fossil record is challenging. Fortuitously, in the marine fossil record, direct records of predatory attacks are provided by trace fossils (e.g., repair scars, bite marks, drill holes) left by predators on skeletons of their prey. A compilation of trace fossil data reveals long-term changes in the intensity and nature of predator-prey interactions in marine ecosystems. Despite numerous interpretative challenges, trace fossils indicate that intensity of predation and predator-prey body size relationships may have changed in a non-monotonic fashion throughout the evolutionary history of aquatic animals. These changes parallel long-term shifts in global biodiversity, faunal composition, and morphology of marine animals pointing to potential causative links between predation and long-term evolutionary and ecological changes in Earth’s oceans.
Speaker: Dr John Alroy
Date: 8th of February 2024
Recording: Please find a recording of the event here.
Scope: Saving biodiversity from extinction is of fundamental importance to people everywhere. Biodiversity must be quantified to demonstrate that mass extinctions have occurred. Diversity estimation turns out to be very difficult because most inventories of communities are too small to catch all of the species. The problem is so hard that researchers continue to use strongly disagreeing strategies. Most aren't helpful. For example, randomly drawing the data down to a least common denominator of data set size (rarefaction) only yields relative diversity estimates. Like most approaches, it is highly inaccurate when most individuals belong to just a few species (so a distribution is uneven). Hill numbers such as Shannon's H and Simpson's D are designed to overweight evenness and minimise the signal of richness. Simple equations called richness indices, such as Chao 1, usually just don't work. I discuss two good solutions to the problem. First, I use simple algebra to derive an equation called the geometric series index. Applying it to a large set of species inventories shows that it has no sample size bias. Second, I discuss properties of an unpublished model of relative abundances that also yields richness estimates. These too are unbiased, but more precise. The distribution is simple, has good theoretical properties, and describes real data accurately. It therefore seems to describe the population dynamics of most ecological communities. The field of biodiversity estimation has been at an impasse for many decades, hindering our understanding of mass extinctions - but unification of the field now seems possible.