Global and local effects of long-term environmental change: a turtle's eye view

Lead Research Organisation: University of Bristol
Department Name: Earth Sciences

Abstract

Turtles, tortoises, and terrapins (collectively termed chelonians) are an immensely successful group of vertebrates that have endured for over 220 million years. They have persisted through numerous major environmental perturbations, including the formation of global hothouse conditions in the Late Cretaceous and Eocene (and associated cooling events), the end-Cretaceous mass extinction, and post-Eocene global cooling trends. How have they responded to these past environmental changes? What can we learn from their history that can be applied to understand past and future responses of biota to long-term environmental change? Chelonians inhabit all three major global realms (marine, freshwater, terrestrial) and chelonian fossils are exceptionally common, have a well-established taxonomy, and their habitat preferences are well-understood. For all of these reasons, chelonians are a near-ideal model system for studying the biotic response of cold-blooded vertebrates to long-term environmental change. This is because we can compare groups characteristic of different habitats and regions as a replicated natural experiment to understand the differential effects of long-term change on ecological subsets of global diversity. Moreover, chelonians are globally threatened, and study of their past reactions to major environmental events will provide the baseline information needed to help predict their possible responses to projected future climate change.

The proposed project is completely novel. We will build a comprehensive database of all chelonian occurrences in the Mesozoic and Paleogene (220-23 million years ago). We will use these data to construct the first-ever rigorous estimate of global chelonian diversity during this interval. We will apply standard and newly developed statistical methods to extract the signal of diversity change from noise resulting from uneven sampling or other biases in the fossil record. We will then use these data to understand how chelonian diversity patterns differ among habitats and regions. Do changes in different regions and habitats occur out of phase or do they act together to create the global pattern?

Most importantly, we will compare the observed diversity patterns with palaeoclimatic data, such as mean annual temperature and precipitation rates, in order to determine if any significant positive (evolutionary radiation or decreased extinction) or negative (decreased origination or increased extinction) changes in chelonian diversity correlate with global or regional environmental perturbations. All of this work will lead to the most detailed understanding of the relationship between chelonian diversity, distribution and climate ever attempted. This will greatly advance our understanding of long-term biotic responses to global change, will be timely in complementing existing work on other groups (primarily mammals), and will provide a deep-time perspective on current biodiversity trends in chelonians and other reptiles. These insights from the fossil record, the only dataset capable of documenting the long-term impacts of climate change, will be of direct relevance to those working on living species. We think that our results will be of major importance to zoologists, conservation biologists, palaeontologists, palaeoclimatologists and macroecologists.

Planned Impact

The impact of this research will benefit four major groups of stakeholders in the UK and internationally:

1. The international scientific community, primarily those working on long-term responses of organisms to global climate change, specifically vertebrate palaeontologists, zoologists, climate scientists and macroecologists.
2. Non-governmental organisations (NGOs), including UK and internationally-based conservation charities, and UK government agencies charged with assessing the impact of predicted long-term climate change on biodiversity conservation strategies.
3. The UK public, which has high levels of societal interest in scientific issues relating to both long-term climate change and palaeontology/evolution.
4. UK-based science educators in schools and colleges, as the proposed project is of direct relevance to topics covered by the National Curriculum, namely biodiversity and the impact of environmental change.

Impact will be achieved in the following ways:

1. Scientific publication in high-profile international journals and presentations at professional meetings (communication with the academic community, NGOs, government agencies).
2. Popular scientific articles in the membership magazines of NGOs, such as those of the World-Wide Fund for Nature (WWF-UK), in Natural History Museum publications, and elsewhere as invited.
3. A range of public outreach activities aimed a both school groups and the general public to be held in the NHM, in conjunction with the museum's educational specialists. These activities will include: 'Nature Live' events (aimed at the public, school groups), which involve 30 minute presentations with the museum and that allow direct communication between the scientists and audience; formal activity-based education events (for both primary and secondary pupils); and provision of a mobile exhibition ('Hands-on Nature') for use with the NHM public galleries (aimed at the public and primary school groups).
4. Public outreach beyond the NHM will include video-conferencing sessions with school groups around the UK. In addition, the 'Hands-on Nature' exhibit will be suitable for touring at other venues, including public science festivals.
5. NGOs (e.g. WWF-UK, Durrell Foundation, Institute of Zoology [IoZ]) and governmental agency representatives (e.g. DEFRA, Natural England) will be invited to attend a half-day workshop on the results of the project, accompanied by a briefing document on how this research might impact future biodiversity and conservation priorities and policy. WWF-UK and the IoZ have already expressed strong interest in the possible benefits of the proposed research (see Letters of Support).

The NHM is ideally placed to promote the results of the research to an exceptionally wide audience. The museum already has excellent, purpose-built facilities in place to deliver many of these activities and an unmatched track record in communicating science to a diverse set of stakeholders.

Publications

10 25 50
 
Description 1) Elucidating the impact of future global climate change on the biogeographic distributions of reptilian ectotherms is of key importance due to their close physiological ties with the thermal environment and their current vulnerable conservation status. Despite this, no studies have yet exploited the deep-time fossil record to address this question, particularly within a rigorous and quantitative model framework. For the first time, we apply an ecological models to quantify the testudine (turtle) climatic niche, and test for niche stability between the Late Cretaceous (Maastrichtian, ~ 72 - 66.0 Ma) and modern. Our findings suggest significant niche stability for several testudine families and ecotypes over an extended evolutionary timescale. We find that long-established testudine families show greater climatic niche stability whereas those diversifying close to the Late Cretaceous display larger niche expansion towards the modern. This is the first study of its kind for any Mesozoic vertebrate group and provides an exciting benchmark for the extension of ecological modelling methods, most frequently applied in the modern or recent palaeo-record to date, to further deep-time palaeoclimate intervals. As such our findings are extremely timely and relevant for conservation policymakers.

More information in the press release http://www.bristol.ac.uk/news/2016/september/turtles-tortoises.html

2) The application of transfer functions on fossil assemblages to reconstruct past environments is fundamentally based on the assumption of stable environmental niches in both space and time. We quantitatively test this assumption for six dominant planktic foraminiferal species, main species to carry information about past climates in the ocean. We contrast reconstructions of species realized and optimum distributions in the modern and during the Last Glacial Maximum (LGM) using an ecological niche model. Niche stability was greatest for (sub)polar species, with greatest expansion of the niche observed for tropical species. The lower observed niche stability for (sub)tropical taxa T. sacculifer and G. ruber (pink) suggests that (sub)tropical temperatures could be underestimated in the glacial ocean with the strongest effect in the equatorial Atlantic where both species are found today.

We assessed the niche responses of testudines (turtles, tortoises and terrapins) to the palaeoclimate transition from a Cretaceous greenhouse to an Oligocene icehouse. Niche dynamics were quantified for freshwater and terrestrial testudine ecotypes and extant families, Trioynchidae and Testudinidae, using a novel combination of ecological niche model (ENM) and phyloclimatic methods. Here we show that testudine niches occupied new habitats opening in response of the climate transition from the hothouse to the icehouse. The freshwater trionychidae niche shows niche stability through time. Under future climate scenarios, testudine niches will likely show poleward range expansion in the northern hemisphere and regional range contractions.
Exploitation Route discussions with conservation groups, NGOs or general conservation policy decision makers
Implications for paleoclimate reconstructinos,
Sectors Education,Environment,Retail

URL http://onlinelibrary.wiley.com/doi/10.1002/2016PA002964/full;
 
Description More than 60 per cent of the group are listed by the International Union for Conservation of Nature (IUCN) as vulnerable, endangered, or critically endangered, because they are being traded, collected for food and medicine and their habitats are being degraded. Understanding the additional impact of global warming and changes in rainfall patterns on their diversity and distributions is therefore paramount to their conservation.As turtles live such long lives, it is impossible to conduct experiments to test for the impact of warming over several generations. The group used a novel combination of state of the art climate models and the deep time fossil record of turtles during warmer times. The results of this study show that during periods with much warmer climates, turtles and tortoises were able to stand the heat in the warmer tropics - as long as there was enough water to support those species living in rivers and lakes. Some groups of turtles have maintained similar niches over millions of years. They have withstood warmer climates in the past and their ability to adapt to the rate of environmental change happening today will be an important factor in their resilience to future climate change. These findings were communicated with stakeholders at an engagement event at the NHM in 2016.
First Year Of Impact 2016
Sector Education,Environment
Impact Types Societal

 
Title Data from PhD Waterson 
Description database of all the data used in the Waterson2017 Paleoceanography paper. Waterson, Amy; Edgar, Kirsty M; Schmidt, Daniela N; Valdes, Paul J (2017): Quantifying the stability of planktic foraminiferal physical niches. Dataset #871284 (DOI registration in progress), Supplement to: Waterson, A et al. (2017): Quantifying the stability of planktic foraminiferal physical niches between the Holocene and Last Glacial Maximum. Paleoceanography, doi:10.1002/2016PA002964 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact paper published in the peer reviewed litatures. No follow on impact just yet as paper has just been published 
URL https://doi.pangaea.de/10.1594/PANGAEA.871284
 
Title terrestrial environmental variables 
Description terrestrial environmental variables used for the turtle model analyses are with the National Geoscience Data Centre d BGS submission ID is 7721. 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact paper published in peer reviewed litatures, discusssion of impacts of findings with stakeholders at the engagement event at the NHM (see submission for the main PI of the project) 
 
Description Collaborative discussion - University of California 
Organisation University of California, Santa Cruz (UCSC)
Country United States 
Sector Academic/University 
PI Contribution Amy has had discussions with Dr. Barry Sinervo at University of California, Santa Cruz about his current research on physiological modelling of turtles and climate constraints during the Eocene
Collaborator Contribution Barry was happy to be involved/updated with Amy's project progress and provide physiological modelling results for comparison (when published) which would be complementary to her palaeo niche modelling research
Impact Amy plans to maintain contact and update Barry with project progress as she develops her palaeo niche models with the turtle data
Start Year 2013
 
Description Collaborative discussion - Zoological Society London 
Organisation Zoological Society of London
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution Amy has met with Dr. Chris Yesson at ZSL to discuss her methodological approaches to the palaeo niche modelling and the possibility of including phyloclimatic (genetic data) in her modelling approach
Collaborator Contribution Chris Yesson (ZSL) is happy to be involved in this aspect of the project providing a suitable phylogenetic tree is available (see MSc project proposal below)
Impact Amy is currently in conversation about developing a phyloclimatic niche model using the palaeo turtle distribution data and palaeoclimatic variables with Chris at ZSL. She has also proposed an MSc Palaeobiology project with Dr. Davide Pisani at the University of Bristol, which would involve the construction of a substantial part of the turtle phylogenetic tree. Once generated this data could then be incorporated into a phyloclimatic niche model
Start Year 2014
 
Description Bristol Festival of Nature (Bristol Dinosaur Project) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach Regional
Primary Audience Schools
Results and Impact Amy volunteered as part of the Bristol Dinosaur Project, helping to run sessions for school groups and the public. The sessions were designed to engage festival attendees with the how Bristol/South West area was millions of years ago and the type of organisms that once lived there

School group visitors gave positive feedback following the interactive sessions
Year(s) Of Engagement Activity 2013
 
Description Green Man Festival, Wales 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Einstein's Garden at Green Man Festival, Wales (August 2016) - Amy and other PhD students developed an interactive stand where they constructed earth's history over the course of the festival, creating a finished "globe" made with natural materials by the end. They spoke about key intervals in earth's history, current climate change and ran arts and craft activities for children ("fossil making" etc).
Year(s) Of Engagement Activity 2016
 
Description Nature Live Talk at the NHM London 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Nature Live Talk at the NHM London ("Turtley not cool") (November 2016) - question and answer session with a general public audience on the findings of the Proc B paper.
Year(s) Of Engagement Activity 2016
 
Description Open doors festival 2013, School of Earth Sciences, University of Bristol 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Amy participated in the Open Doors Event in the School of Earth Sciences at the University of Bristol. As part of a team she coordinated interactive activities and provided information to the visiting public on ocean acidification and the scientific processes that are involved in causing this

Feedback from members of the public was positive - the activities and information provided sparked interesting discussions and further questions about the topic and wider environmental issues, as well as the research that is undertaken at University of Bristol
Year(s) Of Engagement Activity 2013
 
Description PhD project presentation - NCAS Spring school 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Geographic Reach Local
Primary Audience Postgraduate students
Results and Impact Talk generated questions and further discussions with course particpants/leaders afterwards

Discussions following Amy's talk provided useful suggestions from fellow participants of related research groups in the UK and further points of contact that were of relevance to Amy's project aims
Year(s) Of Engagement Activity 2013
 
Description Press release writing, Cabot Institute Press Gang, University of Bristol 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Media (as a channel to the public)
Results and Impact Amy has produced two press release articles to date as part of the Cabot Institute (multidisciplinary research group at University of Bristol dealing with a broad variety of subject areas that relate to environmental uncertainty). Lead authors of the papers to be publicised were interviewed and involved in the review of the articles before release to the University Press Office

Press releases were published on the Cabot Institute website, through the UOB Press Office and via other institutions where non UOB co-author participation was also involved
Year(s) Of Engagement Activity 2014
 
Description Primary school visit (Salisbury) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Amy visited a primary school near Salisbury as part of their Science Week and ran 4 x 40 minute interactive workshops for year groups 1 -3 and reception class about ectotherms. The children were very inquisitive, participated fully and asked great questions during/after the session

Following the workshops Amy received enthusiastic feedback from all staff and the headteacher, she also received requests from several teachers to repeat the workshop at another local primary school
Year(s) Of Engagement Activity 2013
 
Description School Visit (Grammar School Salisbury) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact I gave a presentation on Ocean acidification to the largest cohort of AS and A level Geology pupils in the country with a q and A session at the end. In addition to informing the pupils I also briefed the teachers with information.

questions from the students, raising curiosity, novel research disseminated.
Year(s) Of Engagement Activity 2013
 
Description Secondary School STEM speed-networking workshop, Bristol 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach Local
Primary Audience Schools
Results and Impact Speed networking event at a local secondary school designed to allow AS Level students to find out more about potential career paths in STEM subjects. Students were provided with a brief overview of participating STEM ambassador backgrounds and current careers, with lots of time to then ask questions and pursue any other related issues of interest

Engaging discussions with students and positive feedback from school following the event
Year(s) Of Engagement Activity 2014
 
Description Work with the artist Alice Cunningham 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact I have worked with the artist Alice Cunningham on an exhibition on different aspects of climate change. In a series of meetings we discussed ideas which resulted in drawings and photographic studies. These led to Alice to making a new collection of sculptures from the university's rock archive. The discussions explored notions of tipping points, unprecedented rates of change and unstable objects
Year(s) Of Engagement Activity 2018
URL http://www.alicecunningham.co.uk/