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Life and death in Doñana National Park (Spain): palaeontological and ecological insights from the study of modern vertebrate death assemblages

Periodic Reporting for period 1 - LiveDeadFossil (Life and death in Doñana National Park (Spain): palaeontological and ecological insights from the study of modern vertebrate death assemblages)

Reporting period: 2017-02-01 to 2019-01-31

The fossil record is our primary window to study life in the past and to infer episodes of faunal and floral change associated with past environmental changes. Nevertheless, before obtaining evolutionary or environmental information from the fossil record, it is necessary to evaluate the taphonomic processes that have transformed information from living faunal and floral communities to death assemblages and, eventually, to buried fossil assemblages. Taphonomy is the sub-field of palaeontology that 'studies the transition of the organic remains from the biosphere into the lithosphere' as defined by the Russian palaeontologist I. A. Efremov in 1940.
A synthesis of the processes that result in fossilization can only be achieved if taphonomic analyses are also conducted in modern faunal and floral death assemblages (i.e. actualistic studies). Death-assemblage surveys in modern ecosystems have documented comprehensive information on the multiple processes affecting organic remains and controlling their eventual recycling or preservation.
In the field of mammal taphonomy, the work by Johannes Weigelt (1927) was one of the first studies on the processes governing the death, decomposition and potential preservation of modern vertebrate carcasses. Nevertheless, long-term mammal bone surveys did not started until the 1970s with the work carried out by A.K. Behrensmeyer and others in Amboseli National Park (Kenya). These authors monitorized carcasses of large mammals to (1) compare the faunal representation (fidelity) of the bone assemblage to the living community and (2) document processes that modify modern bone assemblages and result in either their preservation or destruction. Since these initial efforts, a few more mammalian bone surveys have been conducted but are still scarce and have occurred in regions with tropical and temperate climatic regimes. With this project, we seeked to expand the monitoring of modern vertebrate remains to Mediterranean ecosystems. The goal of this research programme is to better understand early postmortem processes that affect the information enclosed in modern death assemblages, and eventually in the fossil record, and that affect our ability to reconstruct past environments and biotas.
The study site is Doñana National Park (DNP), a UNESCO World Heritage Site and Biosphere Reserve, in a Mediterranean biome in Andalusia, Spain. DNP is an excellent natural laboratory for actualistic taphonomic research because: (1) it has been protected since 1969 and is a restricted area devoted to conservation and research (tourism takes place in the periphery of the Park and limited guided tours are permitted inside the Park); (2) this natural area has been intensively studied with several decades of records about the history of the physical environment and censuses of selected vertebrate species; and (3) it includes several habitats that vary according to the local geomorphology.
In addition to offering important insights about the biases and filters that affect recent death assemblages before they become fossil assemblages, this type of studies have been shown to also be a useful, non-invasive way to track different aspects of the living populations (e.g. changes in their abundance, habitat and resource utilization, or mortality through time) in areas lacking historical records, and thereby can be used to inform decisions about conservation biology and wildlife management.
In the course of this action, we have carried out two field campaigns and we have sampled and analyzed from a taphonomical viewpoint 33 transects belonging to 10 different habitats. We have recorded information for a total of 3796 bones belonging to 344 individuals. Relationships have been established between the taphonomic preservation of bones and aspects such as the predatory pressure, the scavengers' action and the depositional environment where bones were found. Also, ecological information regarding the geographic distribution and pr
The main objectives of this project have been fulfilled. Field-work constituted the riskiest part of the project as the fellow was not familiar with the location of the survey, Doñana National Park, and with the monitoring of modern bones. Nevertheless, field work has been carried out succesfully and two field campaigns were conducted: one in September of 2017 and another one in September of 2018 (total of five weeks of field work). Apart from this, intermediate visits were conducted so that the fellow could obtain a better idea of the changes in the DNP landscape throughout the year (for example, the total inundation of the marshes).

The fellow has presented the work of this MSCA in different outlets (both, academic and to the general public). One publication was submitted in May of 2018 but it was rejected (one reviewer rejected the work and another one accepted the work with moderate changes). We decided to wait until we had the field data of 2018 to re-send it again so the paper could have a more definitive and solid speech, so we are now working towards the publication of this work.

The fellow has made the most of her stay at EBD. She made good use of the collections, as it was mentioned in the original project, and constructed a photographic atlas of Doñana mammal bones for her to take to the field. She is also preparing other works previously not mentioned in the original project but that has arisen after her stay at the EBD and the contact established with other researchers and laboratories. For example, we put radio-collars to five cows living at DNP with the aim of understanding the movement of these animals and the use of the habitats. Also, the fellow has collected tooth enamel sample of ungulates from DNP (material housed at the EBD collections). We will carry out stable isotope analyses on these samples in order to better understand the vegetation consumed by these animals, which will provide information about the resource and habitat use of these animals in the park.
The present proposal falls in the realm of basic science so it will provide society with knowledge on the process of fossilization and, eventually, on the history of life on the Earth.
Nevertheless, modern bone surveys also has the potential to provide valuable ecological insights about the mammalian community structures. In this case, we are studying one of the most important natural areas in Europe, so in the long term, outcomes are expected to be useful to wildlife managers, policy makers, and public administrators. In this sense, the LiveDeadFossil project will contribute to the new, cross-disciplinary field of research known as Conservation Paleobiology. This discipline applies the theories and analytical tools of palaeontology to the solution of problems concerning the conservation of diversity. The main message of this field is that 'the perspective provided by geohistorical data is essential for the development of succesful conservation strategies in the midst of a constantly changing environment'.
Society will benefit from the information that this project might have on the preservation of this natural area, which is a sanctuary for millions of birds and also for mammals.
A cow carcass in the Doñana marshes
The beneficiary, Soledad Domingo, examining modern bones from Doñana National Park
A fallow deer from Doñana National Park
Soledad Domingo and field assistants checking out the taphonomic features of a deer carcass