Testing the effect of relative pollen productivity on the REVEALS model: A validated reconstruction of Europe-wide Holocene vegetation

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMReliable quantitative vegetation reconstructions for Europe during the Holocene are crucial to improving our understanding of landscape dynamics, making it possible to assess the past effects of environmental variables and land-use change on ecosystems and biodiversity, and mitigating their effects in the future. We present here the most spatially extensive and temporally continuous pollen-based reconstructions of plant cover in Europe (at a spatial resolution of 1° × 1°) over the Holocene (last 11.7 ka BP) using the ‘Regional Estimates of VEgetation Abundance from Large Sites’ (REVEALS) model. This study has three main aims. First, to present the most accurate and reliable generation of REVEALS reconstructions across Europe so far. This has been achieved by including a larger number of pollen records compared to former analyses, in particular from the Mediterranean area. Second, to discuss methodological issues in the quantification of past land cover by using alternative datasets of relative pollen productivities (RPPs), one of the key input parameters of REVEALS, to test model sensitivity. Finally, to validate our reconstructions with the global forest change dataset. The results suggest that the RPPs.st1 (31 taxa) dataset is best suited to producing regional vegetation cover estimates for Europe. These reconstructions offer a long-term perspective providing unique possibilities to explore spatial-temporal changes in past land cover and biodiversityThis research was funded by the TERRANOVA Project, H2020 Marie Sklodowska-Curie grant agreement no. 81390

Estudio palinológico de turberas holocenas en el sistema central: reconsturcción paisajística y acción antrópica

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología, 1-12-199

Evolución de la vegetación en el sector septentrional del macizo de Ayllón (Sistema Central). Análisis polínico de la turbera de Pelagallinas

Pollen and charcoal analyses of a core from Pelagallinas peatbog, located in the Sierra de Alto Rey at the eastern sector of the Central Mountain Range (Guadalajara), show the environmental history of the montane vegetation during the last 4000 years. The results indícate the importance of pinewoods in the landscape of these mountains. These pine forests were replaced by heather communities contemporaneous with fires as indicated by the increase of particles of charcoal. Birch found refuge in peatbogs, though it nearly disappeared during the last millennium. The Pelagallinas' sequence shows a remarkable and constant presence oí Fagus throughout the core, providing the oldest date for the occurence of this taxon for the Central Mountain Range.Se analiza polínicamente una turbera que abarca los últimos 4000 años y que se ubica en la Sierra de Alto Rey, en la parte oriental del Sistema Central (Guadalajara). Su estudio pone de manifiesto la importancia de los pinares que fueron sustituidos en determinados momentos por brezales coincidiendo con incendios detectados por el incremento de partículas de carbón. El abedul estuvo refugiado en áreas turbosas, llegando a desaparecer en el último milenio. Es de destacar la presencia regular de Fagus a lo largo de toda la secuencia, y la singularidad de ser la cita más antigua de este taxon para el Sistema Central

Drought, fire and grazing precursors to large-scale pine forest decline

Aim Temperate forests are currently facing multiple stresses due to climate change, biological invasions, habitat fragmentation and fire regime change. How these stressors interact with each other influences how, when and whether ecosystems recover, or whether they adapt or transition to a different ecological state. Because forest recovery or collapse may take longer than a human lifetime, predicting the outcomes of different stressor combinations remains difficult. A clearer vision of future forest trajectories in a changing world may be gained by examining collapses of forests in the past. Here, we use long-term ecological data to conduct a post-mortem examination of the decline of maritime pine forests (Pinus pinaster Ait.) on the SW Iberian Peninsula 7000-6500 years ago. Location Portugal and Spain. Methods We compared four palaeoecological records-two with pine declines and two without-using a multiproxy approach. Bioclimatic differences between the four sites were explored. Proxies for past vegetation and disturbance (fire and grazing) were compared with independent palaeoclimatic records. We performed functional traits analysis and used phase plots to examine the causes of pine decline. Results The pine decline represents a critical transition in SW Iberia, which lies close to maritime pine's bioclimatic limits. Prolonged drought likely killed trees and suppressed the fires that normally stimulate pine germination and pinewood recovery. Increased grazing pressure facilitated the rapid spread of resprouter shrubs. These competed with pine trees and ultimately replaced them. Our data highlight complex interactions between climate, fire, grazing and forest resilience. Main Conclusions The pine decline occurred at least a century after post-fire resprouters overtook obligate seeders in the vegetation, constituting an early-warning signal of forest loss. Fire suppression, resprouter encroachment and grazing may threaten the persistence of Mediterranean forests as droughts become more frequent and extreme.PTDC/AAC--CLI/108518/2008info:eu-repo/semantics/publishedVersio

Persistence of tree relicts in the Spanish Central System through the Holocene

Persistence of relict tree species in Mediterranean environments is becoming increasingly unlikely in view of ongoing and future global change. The variability in the Holocene climate and more recent anthropogenic impacts have driven many populations to fragmentation and isolation, and even to extinction. However, some have persisted to the present day. The understanding of their evolution requires long-term studies, in which pollen analysis is a key approach both for formulating hypotheses and supporting results from other disciplines. Mountain ranges have played and still play an essential role as both glacial and interglacial refugia during the Quaternary. The Spanish Central System harbors an exceptional diversity due to its geographical location and complex topography. Some cold-adapted species have survived here with significant proportions of their southernmost populations, often displaying striking adaptations to their changing environments. This work contains a comprehensive review of the palynological investigations conducted in the Spanish Central System, and reveals the distribution of genera such as Taxus, Betula, Fagus, Carpinus and Tilia throughout the Holocene. We also highlight the scarcity of well-dated and high-resolution works, which may contribute to a better understanding of their recent and future evolution.This paper is part of the research carried our within the project "Dinámicas socio-ecológicas, resiliencia y vulnerabilidad en un paisaje de montaña: el Sistema Central (9000 cal. BC-1850 cal. AD) " (R&D National Plan of the Spanish Government, HAR2013-43701-P)

Biomass-modulated fire dynamics during the last glacial-interglacial transition at the central pyrenees (Spain)

Understanding long-term fire ecology is essential for current day interpretation of ecosystem fire responses. However palaeoecology of fire is still poorly understood, especially at high-altitude mountain environments, despite the fact that these are fire-sensitive ecosystems and their resilience might be affected by changing fire regimes. We reconstruct wildfire occurrence since the Lateglacial (14.7. cal. ka BP) to the Mid-Holocene (6. cal. ka BP) and investigate the climate-fuel-fire relationships in a sedimentary sequence located at the treeline in the Central Spanish Pyrenees. Pollen, macro- and micro-charcoal were analysed for the identification of fire events (FE) in order to detect vegetation post-fire response and to define biomass-fire interactions. mean fire intervals (mfi) reduced since the Lateglacial, peaking at 9-7.7. cal. ka BP while from 7.7 to 6. cal. ka BP no fire is recorded. We hypothesise that Early Holocene maximum summer insolation, as climate forcing, and mesophyte forest expansion, as a fuel-creating factor, were responsible for accelerating fire occurrence in the Central Pyrenees treeline. We also found that fire had long-lasting negative effects on most of the treeline plant communities and that forest contraction from 7.7. cal. ka BP is likely linked to the ecosystem's threshold response to high fire frequencies.This research has been funded by the projects DINAMO (CGL2009-07992) (funding EGPF — grant ref. BES-2010-038593 and MSC), DINAMO2 (CGL2012-33063), ARAFIRE (2012 GA LC 064), GRACCIE-CONSOLIDER (CSD2007-00067). GGR was funded by the Juan de la Cierva Program (grant ref. JCI2009-04345) and JAE-Doc CSIC Program, LLM was supported by a postdoctoral MINT fellowship funded by the Institute for the Environment (Brunel University), AMC is a Ramón y Cajal fellow (ref: RYC-2008-02431), APS holds a grant funded by the Aragon Government (ref. 17030G/5423/480072/14003) and JAE holds a grant funded by the Basque Country Government (BFI-2010-5)

The late Holocene extinction of Pinus sylvestris in the West of the Cantabrian Range

Aim To reconstruct the historical biogeography of Pinus sylvestris in the Cantabrian Range (Iberian Peninsula) during the Holocene, and to consider the interactions between vegetation dynamics, climate change and the role of man in the present-day distribution of the species. Location The study site is a mire (1300 m a.s.l.) at Vega de Viejos, on a south-facing slope of the western Cantabrian Range, Spain. The region’s present-day landscape is almost treeless, with the exception of some patches of Quercus pyrenaica and a few copses of Salix and Betula along stream banks. Methods Tree macrofossils from Vega de Viejos were studied by transmitted light and dark-field reflection microscopy; strobili were subjected to comparative morphological analyses. Two Pinus macrofossils were dated by conventional 14C methods. Results The taxonomic accuracy achieved in the identification of the macrofossils provided new information regarding the Holocene history of Pinus sylvestris in this territory. Ninety-five cones of this species were identified; in fact, more than 80% of the 36 identified wood remains were of Pinus gr. sylvestris. Radiocarbon dating revealed that the forest to which the fossils belonged was present until at least 2170 ± 50 yr bp – its disappearance was therefore relatively recent. Main conclusions Pinus sylvestris suffered long-term isolation, and after the Wu¨rm glacial period tended to migrate towards the east. In western Iberia, a temperate climate and autogenic succession favoured broadleaved taxa at the expense of Pinus. Late Holocene human disturbances may have further accelerated the decline of P. sylvestris; in the Cantabrian Range, only a few stands on southern slopes have persisted until the present day. The history of the capercaillie (Tetrao urogallus), a bird characteristic of pure or mixed Palaeartic coniferous forests, was almost certainly affected by the demise of these forests in this area. Cantabrian capercaillies are the only members of this species that live in purely deciduous forests, perhaps a recent adaptation to the regional extinction of pines. Today’s P. sylvestris and capercaillie populations are now highly fragmented and their future, given the predictions of global climate change, is uncertain

Linee guida di buone pratiche per l'identificazione ed il controllo di alcune malattie comuni dei boschi mediterranei

55 páginas, 54 figurasNell’attuale contesto di cambiamento climatico che stiamo vivendo da alcuni anni, le foreste mediterranee sono minacciate da un’ampia varietà di fattori di stress di origine biotica e abiotica. Periodi di siccità prolungata, temperature elevate e incendi boschivi stanno diventando sempre più frequenti nelle nostre foreste. Questi fattori di rischio abiotico sono stati accentuati a causa dell’abbandono rurale, poiché lo spopolamento porta a una diminuzione della pratica della selvicoltura tradizionale che storicamente ha contribuito a mitigare il rischio di incendi e altre minacce per la foresta. Le nostre foreste sono inoltre soggette ad agenti di stress di origine biotica: parassiti e patogeni in grado di indebolire e persino distruggere le masse forestali, che, se colpite dall’azione di insetti e/o microrganismi patogeni, sono più suscettibili a loro volta ad ulteriori elementi di stress. La combinazione di questi elementi nocivi, mette in pericolo la salute e l’esistenza dell’intero ecosistema forestale. Il progetto LIFE MycoRestore nasce con l’obiettivo di implementare diverse strategie per ottenere una gestione sostenibile delle foreste mediterranee e delle loro risorse. A tal fine, vengono utilizzate varie risorse micologiche innovative e pratiche di gestione forestale che consentono un migliore risultato economico, contribuendo nel contempo ad aumentare la resilienza e l’adattamento ai cambiamenti climatici delle foreste mediterranee in Spagna, Italia e Portogallo.LIFE MYCORESTORE. Innovative use of mycological resources for resilient and productive Mediterranean forests threatened by climate change (LIFE18 CCA/ES/1110)Peer reviewe