High-mountain forest resilience

Some high-elevation Pyrenean forests remained virtually pristine during the last 4000 years

Palynological analysis of the last ca. 4300 cal yr BP using a sediment core taken from high mountain (ca. 1900 m elevation) Lake Sant Maurici sediments (southern-central Pyrenees) showed remarkable vegetation constancy during the Late Quaternary.

During the studied period, the vegetation around the lake was dominated by pine (Pinus) forests with birch (Betula), oak (Quercus) and hazel (Corylus) trees, as is the case today.

The composition of these forests and the abundance of their components remained quite stable, despite the occurrence of temperature and moisture shifts.

The degree of human disturbance, notably that of pastoralism and cereal cultivation by scattered and temporary settlements, was very low and had little or no effect on the dominant forests.

This situation contrasts with most high-elevation (subalpine and alpine) environments of the central Pyrenees that were massively anthropized during the Middle Ages.

Past records of this type may allow the estimation of natural and anthropogenic thresholds for irreversible forest changes, which would be useful for conservation purposes.

Reference

Rull, V., Cañellas-Boltà, N. & Vegas-Vilarrúbia, T. 2021. Late-Holocene forest resilience in the central Pyrenean highlands, as deduced from pollen analysis of Lake Sant Maurici sediments. The Holocene (preprint available at PaleorXiv, doi 10.31233/osf.io/mnp3e)

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Posted in My publications, Research papers

Spatiotemporal gradients in the anthropization of Pyrenean landscapes

Pyrenean landscapes were anthropized gradually, from the Bronze Age to the Middle Ages, following a general elevational pattern, from lowlands to highlands. 

Human settlement, as derived from archaeological evidence, may occur much earlier than irreversible anhtropogenic transformation of landscape, as deduced from paleoecological evidence, mainly pollen analysis. The main signs of landscape anthropization are total or parcial deforestation and meadow expansion (landscape opening), treeline lowering, unexpected changes in forest composition, increases of fire incidence, and intensification and/or expansion of cropping and grazing practices.

In a paper that will be published soon in Quaternary Science Reviews, we identified a general upward anthropization trend in the southern-central Pyrenees from the Bronze Age (basimontane belts) to the Middle Ages (subalpine and alpine levels), which progressed at a general average rate of 40 m elevation per century.

The elevational gradient is most clear between the Bronze Age and the Roman occupation, suggesting a progressive upward anthropization trend from the south with the likely involvement of Iberian cultures. During the Middle Ages, a massive anthropization pattern of subalpine/alpine areas is observed; this pattern is chronologically consistent with the incursion of northern cultures crossing the Pyrenees and the development of extensive high-mountain pastoralism and horizontal transhumance.

Further work is needed to confirm these observations, especially in areas with few available paleoecological studies, notably the basal and montane belts. It could be interesting to develop similar studies on other Pyrenean regions and other mountain ranges.

Reference

Rull, V. & Vegas-Vilarrúbia, T. 2021. A spatiotemporal gradient in the anthropization of Pyrenean landscapes. Preliminary report. Accepted in Quaternary Science Reviews. Preprint available at PalorXiv, doi 10.31233/osf.io/9u2b5

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Posted in My publications, Research papers

Sittin’ on the dock of the bay

Posted in Tunes

Back to the Botanic Institute

After five years (2015-2020) in the Institute of Earth Sciences Jaume Almera (ICTJA), now Geosciences Barcelona (GEO3BCN), I am coming back to the Botanic Institute of Barcelona (IBB), both belonging to the Spanish Council for Scientific Research (CSIC). The IBB lies within the Montjuïc Park, one of the most beautiful places in Barcelona, situated on a hill with splendid views of the city and the sea, as well as emblematic sites such as palaces, castles and other historical buildings, museums, the Joan Miró Foundation, the 1992 Olimpic Ring and numerous gardens including the city Botanical Garden, just to cite some. The IBB is situated near the top of the hill, inside the terrains of the Botanical Garden (see the interactive map below).

In the IBB, I will be happy again and will spend the last five years of my professional career working on my usual topics, with emphasis on the paleoecology of the Pyrenees, my homeland. I will also take the opportunity to synthesize the research that I have carried out for more than 40 years, to try to leave something useful to future generations, provided they are interested in my experience. This summarizing task has already begun in the last couple of years with the publication of some general books and review papers, and I hope that the IBB will be a perfect place for its continuation.

The research group on palynology and paleoecology that I founded almost 20 years ago and the associated Laboratory of Paleoecology (PALAB) will continue to develop their usual tasks in the GEO3BCN institute, under the leadership of two of my former PhD students, who have already become independent researchers: Encarni Montoya and Núria Cañellas-Boltà, with whom I will maintain permanent contact and collaboration.

Click here to access my new contact information.

Posted in PALAB

My three pandemic books

Since the declaration of the COVID19 pandemic and the implementation of the corresponding lockdown measures, I have had to work at home, just as many inhabitants of the planet. Fortunately, part of my job is to write scientific publications and that has been my main task in these months, during which I have published three books and have obtained the editorial acceptance for a fourth book to be published next year.

These books have been issued by relevant international publishers like Elsevier/Academic Press and Springer Nature and can be found on the “Books” page of my personal website. You can also click the below titles for more information.

Rull, V. 2020. Paleoecological Research on Easter Island. Insights on Settlement, Climate Changes, Deforestation, and Cultural Shifts. Elsevier, Amsterdam. ISBN 978-0-12-822727-5.

Rull, V. & Carnaval, A. (eds.). 2020. Neotropical Diversification: Patterns and Processes. Springer, Berlin. ISBN 978-3-030-31167-4.

Rull, V. 2020. Quaternary Ecology, Evolution, and Biogeography. Academic Press, London. ISBN 978-0-128-20473-3.

To be published in 2021:

Rull, V. & Stevenson, C. (eds.). The Prehistory of Easter Island (Rapa Nui): Towards an Interdisiplinary Integrative Approach. Springer, Berlin.

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Posted in Books, My publications, Science

Dreams

Posted in Tunes

What is the most biodiverse tropical region?

According to a recent paper by Peter Raven and collaborators, the Neotropics is the most biodiverse tropical region in absolute terms, encompassing one third of global diversity, but Southeast Asia is proportionally richer if we consider its smaller area.

Reference: Raven PH, Gereau RE, Phillipson PB, Chatelain C, Jenkins CN, Ulloa C. 2020. The distribution of biodiversity richness in the tropics. Science Advances 6, eabc6228.

Abstract: We compare the numbers of vascular plant species in the three major tropical areas. The Afrotropical Region (Africa south of the Sahara Desert plus Madagascar), roughly equal in size to the Latin American Region (Mexico southward), has only 56,451 recorded species (about 170 being added annually), as compared with 118,308 recorded species (about 750 being added annually) in Latin America. Southeast Asia, only a quarter the size of the other two tropical areas, has approximately 50,000 recorded species, with an average of 364 being added annually. Thus, Tropical Asia is likely to be proportionately richest in plant diversity, and for biodiversity in general, for its size. In the animal groups we reviewed, the patterns of species diversity were mostly similar except for mammals and butterflies. Judged from these relationships, Latin America may be home to at least a third of global biodiversity.

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Posted in biodiversity, Research papers

Are we in the Anthropozoic era?

The manuscript entitled: The Anthropozoic era revisited, by V. Rull, has been accepted for publication in the journal Lethaia. The abstract is provided below.

Abstract: This paper explains in some detail the poorly known proposal of Stoppani (1873) regarding the Anthropozoic era, whose beginning was defined by the first traces of human presence on Earth. This author set the stratigraphic bases for the definition of the “human era”, but the proposal had two main weaknesses: the dismissal of biological evolution and the lack of an absolute chronology. Further developments in radiometric/palaeomagnetic dating and the elucidation of the main trends and timing of human evolution have provided the necessary information to update the original Anthropocene proposal in chronological terms, maintaining Stoppani’s original definition and stratigraphic markers. This updated proposal follows the rules of the International Stratigraphic Guide and situates the beginning of the Anthropozoic era at the beginning of the Quaternary, the time at which the first human fossils, corresponding to the first species of the genus Homo, and corresponding cultural manifestations have been identified and dated. Therefore, the new Anthropozoic era would follow the Cenozoic era, which ended with the Neogene period. Defined in this way, the Quaternary period and its Pleistocene and Holocene epochs would be situated in the new Anthropozoic era. The main strengths and weaknesses of the updated Anthropozoic version are discussed. It is suggested that the updated Anthropozoic proposal might be fully elaborated to evaluate whether it should be submitted to the International Commission on Stratigraphy and the International Union of Geological Sciences for its eventual formalization.

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Posted in My publications

The three dimensions of human impact on island vegetation

The manuscript entitled: Pristinity, degradation and replacement: the three dimensions of human impact on island vegetation, by V. Rull, has been accepted for publication in the journal Progress in Physical Geography. The abstract is reproduced below.

Abstract: This paper presents three extreme examples of the potential consequences of human settlement on the vegetation of oceanic and continental islands. The Neotropical Pantepui continental archipelago of sky islands is an example of pristinity, which is due to the almost nonexistent human impact because of the remoteness and inaccessibility of these islands as well as the lack of natural resources to exploit. Easter Island is used to illustrate total vegetation degradation by deforestation and the exhaustion of natural resources, which has transformed the island into badlands with no signs of recovery. The Azores Islands have been chosen to illustrate replacement as, after initial postsettlement deforestation and extractive practices, a further transformative phase consisting of creating an almost totally anthropogenic vegetation with mostly exotic species occurred. The paper describes in some detail the developments of each case and the historical context in which they took place using historical, archeological and paleoecological evidence. Many intermediate states are possible among these three extremes, which can be represented with a ternary diagram (the PDR diagram), which is useful for characterizing the state of each island or archipelago in terms of human impact on terrestrial ecosystems and informing conservation and restoration practices.

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Posted in My publications

The Elsevier book on the paleoecology of Easter Island already published!

Editorial summary. This book synthesizes the available paleoecological knowledge from the last millennia of Easter Island to pave the way towards an integrated interdisciplinary vision of the island’s environmental-ecological-cultural system as a complex functional unit. Human and environmental deterministic views are avoided, and the Easter Island prehistory is analyzed under a holistic perspective of feedbacks and synergies among the different components of the system. The book examines the Easter lsland’s climatic and ecological history, a topic that is not usually addressed in other literature on the island. The book provides a thorough and synthetic account of all paleoecological works developed to date including the latest discoveries. Finally, it attempts to match paleoecological evidence with the results of other disciplines, in the way towards a multidisciplinary framework. The thorough and detailed view of the climatic, environmental and ecological history of the island provided by the book makes it a useful resource for researchers, university professors and graduate students of a varied range of disciplines including ecology, paleoecology, paleoclimatology, biogeography, sedimentology, limnogeology and others who are interested in incorporating paleoecological knowledge in their investigations.

Download the front matter with the table of contents and the introduction for more information.

Reference

Rull, V. 2020. Paleoecological Research on Easter Island: Insights on Settlement, Climate Changes, Deforestation and Cultural Shifts. Elsevier, Amsterdam. ISBN 978-0-12-822727-5.

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Posted in Books, My publications