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The Dutch Aamsveen lies in a glacial basin in the Dutch-German border area. It consists of remnants of a cross-border raised bog and a lagg with degrading species-rich basiphilous plant communities. Farther west, the Glanerbeek drains the footslope at the edge of the basin and adjacent lagg. For the Netherlands, this is a rare wetland ecosystem and an important Natura 2000 area, but it is threatened by ongoing degradation. A spatiotemporal landscape ecological system analysis (LESA), including extensive palaeoecological research, showed the fundamental role of the interplay between infiltrating acid bog water that gradually acquires basic cations from the underlying base rich sediments as it flows laterally towards the lagg, where it seeps up, and the (lesser) influx of base rich surficial groundwater from the ice-pushed ridge in the west. Anthropogenic disturbance of this interplay has led to serious system degradation. The results of this LESA served to develop an integrated management plan at landscape level, instead of habitat level plans as is usual in the context of Natura 2000. This study illustrates the relevance of a spatiotemporal LESA for the recovery and sustainable management of such complex, dynamic systems.

A synthesis of the current knowledge of the so-called Italian giacimenti a olle d’impasto rossiccio (reddish jar potsherd deposits) is presented. These sites are common along the Tyrrhenian side of Central Italy and are usually interpreted as salt-production sites, because of parallels with similar European specialised sites. In the latter, salt was obtained by boiling a brine in special disposable pottery, a technique known as briquetage. However, the analogies are not straightforward and alternative hypotheses, e.g. fish-processing, and a more complex intertwined economy have also been put forward. To solve the interpretation issues, we advocate to use a multidisciplinary approach involving quantification of the ceramics encountered, establishment of their morphological and functional typologies, and physico/chemical analyses to identify their use.

A seguito della sintesi pubblicata sulle indagini archeologiche nel territorio di Sezze, condotte dall'Università di Groningen sotto l'egida del Progetto della Regione Pontina (PRP), questo documento discute la metodologia e i primi risultati di due progetti di ricerca sul campo più recenti nel quadro del PRP, entrambi finanziati dall'Organizzazione olandese per la ricerca scientifica (NWO): 1) l'Avellino Event Project (AVP) delle Università di Groningen e Leiden che studia gli effetti distali della grande eruzione del Vesuvio risalente all'età del bronzo sull'ambiente umano della pianura di Fondi e della pianura Pontina. 2) il progetto dei Centri Minori che studia lo sviluppo degli insediamenti di Forum Appi e Ad Medias lungo la Via Appia in relazione allo sviluppo della campagna romana. Entrambi i progetti contribuiscono in modo significativo alla ricostruzione a lungo termine del paesaggio umano nella pianura di Sezze e aprono prospettive su ulteriori lavori interdisciplinari., IpoTESI di Preistoria, V. 11, N. 1 (2019)

In de klimaatdebatten van het afgelopen voorjaar kwam de Klimaattafel Landbouw en Landgebruik met een vrij spectaculaire oplossing voor het probleem van zakkende veenweidegebieden. Door een slimmere manier van draineren zouden de CO2-emissies minstens gehalveerd worden en zouden de boeren gewoon door kunnen gaan met de veehouderij. Te mooi om waar te zijn?

A seguito della sintesi pubblicata sulle indagini archeologiche nel territorio di Sezze, condotte dall'Università di Groningen sotto l'egida del Progetto della Regione Pontina (PRP), questo documento discute la metodologia e i primi risultati di due progetti di ricerca sul campo più recenti nel quadro del PRP, entrambi finanziati dall'Organizzazione olandese per la ricerca scientifica (NWO): 1) l'Avellino Event Project (AVP) delle Università di Groningen e Leiden che studia gli effetti distali della grande eruzione del Vesuvio risalente all'età del bronzo sull'ambiente umano della pianura di Fondi e della pianura Pontina. 2) il progetto dei Centri Minori che studia lo sviluppo degli insediamenti di Forum Appi e Ad Medias lungo la Via Appia in relazione allo sviluppo della campagna romana. Entrambi i progetti contribuiscono in modo significativo alla ricostruzione a lungo termine del paesaggio umano nella pianura di Sezze e aprono prospettive su ulteriori lavori interdisciplinari. -- Following a synthesis of published archaeological investigations in the territory of Sezze by the team of the University of Groningen within the Pontine Region Project (PRP), this paper discusses the methodology and first results of two more recent fieldwork projects within the framework of the PRP, both funded by the Netherlands Organisation for Scientific Research (NWO): 1) the Avellino Event Project (AVP) of the universities of Groningen and Leiden that studies the distal effects of the great Bronze Age eruption of mount Vesuvius on the humanenvironment of the Fondi and Pontine plains. 2) the Minor Centres project that studies the development of the settlements of Forum Appi and Ad Medias along the Via Appia in relation with the development of the Roman countryside. Both projects add significantly to the long term reconstruction of the human landscape in the plain south of Sezze as well as open up perspectives on further interdisciplinary work.

Sinds het midden van de vorige eeuw heeft de Nederlandsenatuur te lijden gehad van overmatige zuur- en stikstofdepositie. Maatregelen om de effecten hiervan te bestrijden, leidden niet altijd tot het gewenste resultaat en hadden soms dermate sterke neveneffecten dat ze eerder ongewenst waren. Sinds kort is steenmeel in beeld als middel dat mogelijk wel de positieve effecten maar niet de neveneffecten heeft. Kennis over de effecten vansteenmeel op gedegradeerde natuur en bos is echter nog lang geen gemeengoed. Op 18 februari 2019 organiseerden de VBNE en het OBN Deskundigen team Droog zandlandschap een discussiedag voor onderzoekers en andere direct betrokkenen rond het onderwerp “Steenmeel als herstelmaatregel” om kennis, inzichten en onzekerheden rond dit thema uit te wisselen en mogelijke richtlijnen te bespreken voor een eventuele toepassing van steenmeel als herstelmaatregel in natuurgebieden.

Chapter 4 is dedicated to optically stimulated luminescence dating. This technique became available in the 1990s. Also for this dating technique it is valid that detailed knowledge of the technique and the sample properties are crucial for the interpretation of the dates. The case studies of polycyclic driftsand deposits and plaggic Anthrosols demonstrate the differences in ages of organic and mineral fractions of soil samples and how to interpret this in the context of soil genesis.

Sinds het midden van de vorige eeuw heeft de Nederlandse natuur te lijden gehad van overmatige zuur- en stikstofdepositie. Maatregelen om de effecten hiervan te bestrijden, leidden niet altijd tot het gewenste resultaat en hadden soms dermate sterke neveneffecten dat ze eerder ongewenst waren. Sinds kort is steenmeel in beeld als middel dat mogelijk wel de positieve effecten maar niet de neveneffecten heeft. Kennis over de effecten van steenmeel op gedegradeerde natuur en bos is echter nog lang geen gemeengoed. Op 18 februari 2019 organiseerden de VBNE en het OBN Deskundigenteam Droog zandlandschap een discussiedag voor onderzoekers en andere direct betrokkenen rond het onderwerp “Steenmeel als herstelmaatregel” om kennis, inzichten en onzekerheden rond dit thema uit te wisselen en mogelijke richtlijnen te bespreken voor een eventuele toepassing van steenmeel als herstelmaatregel in natuurgebieden.

The molar of a giant deer, Megaloceros giganteus (Blumenbach, 1799), was discovered in sandy deposits of the North Sea, about 10 km west of the present shoreline of the Netherlands. Compacted masticated plant remains were preserved in the molar's deep folds. A palaeoecological analysis of these plant remains shows the complete dominance of pollen from Artemisia (sage) and other Asteraceae Tubuliflorae (Compositae), indicating that the animal foraged in a steppe environment, and may have preferred to eat Artemisia, which contain a high level of nutrients such as calcium and phosphorous components, which are important for antler building. Radiocarbon dating indicates that the plant remains are of mid‐Weichselian age [38 570 (+300, −290) 14C a BP, Greenland Interstadial‐11]. This is the first study of the food choice of M. giganteus based on palaeoecological evidence. We hypothesize about links between the extirpation of M. giganteus at the onset of the Holocene in North‐West Europe and the transition from a landscape with highly dynamic geomorphological processes and consequently prevalence of immature and nutrient‐rich soils, to a less dynamic landscape with stable, leached and acidifying soils, and the decline of Artemisia and other calciphilous plants.

A lithoid tuff, found in 2011 (Ricci pit, Agro Pontino, Southern Lazio, Italy), was studied for its composition, origin and palaeogeographical implications. This tuff was the first occurrence of a Würmian-age tephra layer, encountered in the coastal basins of Southern Lazio. Based on its mineralogy and isotopic composition (Sr and Nd), its stratigraphic position and the pre- and post-depositional soil formation and weathering, it was identified as a distal tephra deposit from the Colli Albani volcano, connected with the Albano 5-7 eruptive stage and dating from 40-36 ka BP. The lithoid tuff consists of tephra that were slightly reworked and subsequently lithified, when this central part of the Agro Pontino graben still consisted of a non-dissected, level lagoonal plain. The study confirms the earlier established importance of this tephra layer as stratigraphic marker for Central Italy, and shows that its distribution is wider than earlier assumed, notably to the SE of the Colli Albani volcano.

Het Beerzerveld is deel van het Natura 2000-gebied Vecht en Beneden-Regge en bestaat uit een complex mozaïek van droge en natte habitats. In de natte gebieden lijkt sprake van verdroging. Bijzonder is dat de veentjes hoog liggen in het landschap en grenzen aan lager gelegen, drogere gronden met heiden. Hoe is deze ‘omgekeerde wereld’ nu precies ontstaan en is er inderdaad sprake van daling van de waterstand? Zo ja, waardoor? En welke implicaties heeft dit voor het hydrologisch functioneren? Op grond van de resultaten van het onderzoek worden beheermaatregelen aanbevolen.

Volcanic ash soil contains large stocks of organic matter per unit area. A large proportion of organic matter is stored in the subsoil; therefore, a thorough understanding of its vertical distribution is needed to predict the effects of change in climate and land use. Faunal bioturbation is often cited as the dominant process that affects the vertical distribution of organic matter. An additional but often overlooked process is change in the volume of the soil. Such change might affect the vertical distribution of organic matter by changing the position of the soil surface, which can affect the soil-forming processes related to depth, such as weathering, decomposition, bioturbation and rooting. We calculated the change in volume with geochemical mass balance equations, and showed the effect of change in soil volume on the vertical distribution of organic matter using a dynamic model. Then we evaluated the plausibility of the model concept with an independent model for parameter identification and through a model sensitivity analysis. Results show that volume change is a major soil-forming process that determines the vertical distribution of organic matter in volcanic ash soil as the active bioturbation zone moves upwards in response to soil thickening.

In recent years it was discovered that the Middle to Late Holocene infi ll of the Agro Pontino graben (Central Italy) held a tephra layer originating from the Avellino eruption of the Vesuvius volcano. The eruption is dated to 1995 ± 10 calBC and took therefore place during the Early Bronze Age. This was a violent eruption, covering large parts of Campania, the region in which the volcano is situated, with its ashes. The local population had time to fl ee, but did not return for a period of hundreds of years. One of the possibilities is that people fl ed to the quiet Agro Pontino, at a distance of 120 km, to settle. The fact that the low-lying parts of the graben hold wet, organic deposits of the appropriate age, containing the Avellino tephra layer, provided an opportunity to assess whether an infl ux of new inhabitants is discernable directly after the Avellino event, as a substantial number of newcomers might be detected by an intensifi cation of anthropogenous stress on the environment. The question is tackled by means of pollen analysis, plant macro-remains, malacology and a small excavation. The outcome of these investigations shows that some impact on the environment is visible, but that it is far from clear whether this effect is due to people from abroad or due to an increase of the local population.

This paper presents the first results of a landscape archaeological project carried out in the territory of the ancient colony of Aesernia, modern Isernia, in Molise, Central-Southern Italy. The nature of Roman Republican colonization is currently heavily debated, and the field project aims to contribute to this discussion by investigating the non-urban aspect of a Roman Republican colony that was established in the midst of the Apennine mountains in 263 BC. Through a combination of extensive field surveys (seasons 2011-2013) and geological and geomorphological analysis, the preliminary results show the potential of a landscape archaeological approach and the diversity of settlement strategies within the colonized areas according to different landscape conditions.

Resumen Este estudio presenta una primera aproximación a la relación entre hidrología,calidad del agua, geología y suelos para un ecosistema de jalca cerca de Cajamarca en el norte de Perú. Debido a que las áreas de jalca son propensas a la degradación de sus suelos húmicos, como resultado del uso del suelo y del cambio climático, se requiere mayor información sobre su hidrología y geoecología. Durante dos campañas de campo se evaluó la geología, geomorfología, suelos y vegetación del área. Además, se realizaron mediciones de conductividad eléctrica hidrológica y se tomaron muestras a lo largo de varias quebradas (arroyos). Aunque en la región hay importantes proyectos mineros, no existe actividad minera en las cuencas estudiadas. Los suelos mostraron una clara relación con su sustrato y en muchos casos tuvieron un alto contenido de materia orgánica, que se demuestra por el predominio de horizontes A mólicos y úmbricos. La hidrología es impulsada por un excedente de agua de alrededor de 300 mm por año y el caudal de los ríos está íntimamente relacionado con la estacionalidad de las lluvias. Hemos encontrado que existe una clara relación entre el sustrato subyacente y la química del agua de los arroyos y pantanos. Se pueden distinguir dos tipos de agua: uno originado de rocas extrusivas dacíticas (ignimbritas), con niveles extremadamente bajos de sólidos disueltos totales, un predominio de Ca2+ y HCO3 -, niveles de sodio relativamente altos y una baja RAS (relación de adsorción de sodio). El otro tipo de agua se origina en zonas de roca madre dominadas por calizas, mostrando niveles mucho más altos de sólidos disueltos totales. La contaminación química del agua, expresada en nitratos y amonio, estuvo relacionada especialmente con zonas pobladas. Abstract This study gives a first approximation of the relationship between hydrology and water quality, geology, and soils for a jalca ecosystem near Cajamarca in Northern Peru. As the jalca areas are prone to degradation of their humic soils as a result of land use and climate change, more information is needed on their hydrology and geoecology. During two field campaigns the area was surveyed with regard to geology, geomorphology, soils, and vegetation. Furthermore, hydrological routings were executed, measuring electrical conductivity (EC25) of stream waters and selectively sampling these waters. Soils showed a clear relationship with their substrate and were in many cases high in organic material as shown by the dominance of mollic and umbric A horizons, respectively. The hydrology is driven by a water surplus of around 300mm per year, and stream discharge is closely related to the seasonality of the rainfall. We found that there is a clear relationship between the underlying substrate and the water chemistry of the streams and fens. Two set of water types can be distinguished: one originating from dacitic extrusive rocks (ignimbrites), with extremely low total dissolved solid levels, a dominance of Ca2+ and HCO3 -, and relatively high sodium levels and with low SAR (sodium adsorption ratio) values. The other type of water originates from limestone dominated bedrock areas, showing much higher total dissolved solid levels. Chemical water pollution, as expressed by nitrates and ammonium, was especially related to settlements.

In het kader van ecologisch herstel en ter aanvulling op eerder uitgevoerd inventariserend onderzoek is een bodemonderzoek uitgevoerd van het eigendomsgebied van het GNR ‘de Monnikenberg’. Naar aanleiding van de verworven resultaten zijn de eerder gemaakte inrichtingsplannen uit het Alterra rapport 2209 (2011) besproken en waar mogelijk voorzien van aanbevelingen.

Het behoud en herstel van de grote hoogveenrestanten in Nederland lijkt langzaam de goede kant op te gaan. De habitattypen Herstellend hoogveen (H7120) en Actief hoogveen (H7110_A) worden in het kader van Natura 2000 beschermd en herstelmaatregelen worden geformuleerd. Een kennisvraag die reeds sinds het begin van het OBN-hoogveenonderzoek in 1997 is gesteld, maar nog niet beantwoord is, is de vraag naar mogelijke aantastingen van ‘de veenbasis’. Dit rapport geeft geen antwoord op de vraag, maar biedt een literatuurstudie en kennisoverzicht van de processen die een rol kunnen spelen in de veenbasis en formuleert de onderzoeksvragen die naar het antwoord op deze vraag moeten leiden.

Resumen Los suelos del páramo almacenan cantidades excepcionales de carbono debido a las condiciones edáficas y climáticas sobre las cuales se desarrollan. Este gran reservorio de carbono está amenazado debido a los efectos del cambio climático y las dinámicas de uso de la tierra. No obstante, el desarrollo de mecanismos de mitigación como los promovidos por REDD+ son una alternativa que puede ayudar a reducir los impactos de estas amenazas y promover su conservación. Sin embargo, para la aplicación de estos tipos de mecanismos es fundamental que los procesos asociados al mantenimiento y dinámica del ciclo del carbono sean comprendidos y los posibles impactos puedan ser proyectados. En este trabajo, a partir de una extensa revisión de artículos indexados, se presenta una síntesis del estado actual del conocimiento y se discute las ventajas y limitaciones de la aplicación de modelos de carbono orgánico del suelo y sus parámetros asociados. Como resultado de esta revisión, concluimos que los modelos disponibles actualmente contienen limitaciones importantes asociados a los procesos y flujos de la descomposición de la materia orgánica que impiden su aplicación en los páramos andinos. Adicionalmente, información sobre las variables de ingreso es limitada y lo mismo aplica para información independiente que permita validar los resultados modelados. El artículo concluye con recomendaciones sobre prioridades futuras de investigación, enfatizando la urgencia del desarrollo de estudios comparativos sobre los efectos del uso de la tierra en la dinámica del carbono, en lugar del desarrollo de estudios experimentales en condiciones controladas. Abstract Paramo soils store exceptionally large amounts of carbon because of the specific edaphic and climatic conditions in tropical high-altitude ecosystems. This soil C-stock is threatened by changes in climate and land use, but potentials for its conservation on the basis of REDD+ type mechanisms are high. However, for application of such mechanisms it is crucial that properties and processes involved are adequately understood and impacts can be predicted. In this paper, an overview is given of the current knowledge and applicability of soil carbon models and parameters involved, based on a full search of publications in international refereed journals. The conclusion is that existing models are not readily applicable to paramo soils because of the specific decomposition processes and pathways. Moreover, information on relevant input parameters is scant and the same holds for data that can be used to validate model outputs. Recommendations are given for future research, emphasizing the urgency of comparative studies of land use impacts, rather than of experimental studies.

Resumen Se estudiaron los suelos, los registros de polen y los marcadores biológicos en transectos entre bosque y páramo en la reserva natural Guandera al norte del Ecuador para reconstruir el límite superior del bosque y establecer sus características y dinámicas. Se encontró que los suelos estaban marcados por una acumulación extrema de materia orgánica, índices muy bajos de descomposición y una actividad biológica específica del ecotono. También se estableció que los suelos guardan excelentes archivos de la vegetación del Holoceno en forma de registros de polen y de marcadores biológicos. Estos últimos parecían ser específicos de determinadas plantas y permitieron una reconstrucción nueva y detallada de la vegetación específica del sitio y de su historia. La combinación de los datos del suelo, los registros de polen y los perfiles de los arcadores biológicos indicaron que todos los sitios actualmente boscosos (3.500-3.600 msnm) estuvieron previamente bajo vegetación de páramo en algún momento durante el Holoceno y que el LSB cambió repetida y rápidamente. Los sitios de páramo (3.700 msnm y más altos) nunca estuvieron debajo de bosques durante el Holoceno. Así, debe aceptarse una altitud de alrededor de 3.700 msnm como el límite superior de forestación ecológicamente sostenible. Abstract Soils, pollen records and biomarkers were studied in forest-paramo transects in the Guandera nature reserve in northern Ecuador to reconstruct the upper forest line (RUFLE) and establish its characteristics and dynamics. Soils were found to be marked by extreme accumulation of organic matter, very low decomposition rates and ecotone specific biological activity, and also hold excellent archives of the Holocene vegetation in the form of pollen records and biomarkers. The latter appeared to be plant specific and allowed for a novel, detailed reconstruction of the site-specific vegetation and its history. Combination of soil data, pollen records and biomarker profiles showed that all currently forested sites (3.500-3.600 m asl) were previously under páramo vegetation at some time during the Holocene and that the UFL repeatedly and rapidly shifted. The páramo sites (3.700m asl and higher) were never under forest throughout the Holocene. Thus, for the upper limit of ecologically sustainable afforestation an altitude of about 3.700 m asl is to be accepted.

Resumen La Jalca, considerada como un área de transición entre los páramos y la puna, es también un ecosistema de pastizales altoandinos naturalmente fragmentado con una creciente actividad humana que no ha sido cuantificada aun en detalle. Este estudio tiene por objetivo analizar el cambio del uso del suelo y los cambios en la configuración espacial de los parches (fragmentación) de la jalca del sur de Cajamarca. Usando imágenes satelitales de 1987 y 2007 (LANDSAT 5TM) se reconstruyeron mapas de cobertura y se identificaron los parches de jalca para cada año. Nuestros resultados muestran que la jalca se redujo en un 25% (75.000 ha) durante el periodo analizado. La actividad agrícola es la principal responsable de esta pérdida en extensión de Jalca, especialmente en las zonas más altas donde los cultivos han ocurrido a mayores alturas en el 2007 que en 1987. Sin embargo, en términos relativos el incremento de plantaciones (1000%) y minería (500%) es más dramático que el de la agricultura (26%). Adicionalmente se observa un proceso de fragmentación creciente donde los parches de jalca se están volviendo más pequeños y perdiendo los límites naturales de jalca-bosques o jalca-arbustales para estar rodeados de actividades humanas. Abstract The Jalca, a transitional area between the paramos and the puna, is also a naturally fragmented grassland ecosystem with an increasing human activity not detailed quantified yet. This study analyzes: 1) the land use and land cover changes and 2) changes in the spatial configuration (fragmentation) of the Jalca of South Cajamarca. Land cover maps were constructed by classifying satellite images (LANDSAT 5M) taken on 1987 and 2007 to analyze land cover and land use change and Jalca patches were identified from those maps for the fragmentation analysis. Our results show a reduction of Jalca areas by 25% (75.000 ha) between 1987 and 2007. Agriculture is the main driver of this reduction in extent especially in the upper zones of the Andes showing an upward expansion of crops. However, in relative terms, the increase in plantations (1000%) and mining areas (500%) is more dramatic than that of agriculture (26%). Additionally the Jalca has suffered a fragmentation process where Jalca patches have become smaller and have lost the natural borders jalca-forest and jalca-shrublands to be surrounded by human activities.

A unique complex of multiphased Holocene drift sands and paleosols, with at least two lacustrine phases, was discovered during a major sanitation project in the Laarder Wasmeren area near Hilversum, the Netherlands. The complex could be studied in detail, highly facilitated by the excellent and large-scale exposure of the various deposits and soils. OSL dating was used to establish ages of the phases, where possible differentiating between time of deposition and time of burial by taking into account the potential effects of bioturbation. Pollen analysis served to reconstruct the vegetation during the various phases. A first minor phase of aeolian activity already started before approx. 5,000 BC, followed around 4,000 BC by a second phase and a rather massive third phase around 3,000 BC. After a long phase of soil formation, the latest, massive drift sand phase started around the 14th to 15th century. It clearly represents the classic drift sand phase that started in the Late Middle Ages in the Netherlands. Sand drifting followed on soil forming phases during which the vegetation became increasingly dominated by ericaceous plants and culminated in heathlands. The first three aeolian phases and associated heathlands are much older than generally assumed for heathland and drift sand to occur in the Netherlands. Moreover, podzolisation was found to have started very early, true podzols already occurring before 4,000 BC. Around 3,000 BC groundwater in the area reached a maximum altitude of about 230 cm +NAP, resulting in local open water in the area. This rise is probably linked to the development of the Dutch coastal area, where at that time peat accumulated and drainage was poor, inducing a rise of the groundwater level in ‘het Gooi’. This groundwater level fell later on, to never reach this altitude again. The Groot Wasmeer was formed by local stagnation on a slowly permeable podzol and already reached a level of 320-325 cm +NAP by 400 BC, which more or less equals its 20th century level. The results demonstrate that earlier concepts on the occurrence and age of aeolian phases, podzols and heathland vegetations in the Netherlands are far too schematic, and that early, pre-agricultural cultures may already have had an impact on the stability of fragile cover sand landscapes, e.g. through burning. Results are in line with those from several contemporary studies on early prehistoric cultures and their impact in river dune areas in the Central and Eastern Netherlands.

A unique complex of multiphased Holocene drift sands and paleosols, with at least two lacustrine phases, was discovered during a major sanitation project in the Laarder Wasmeren area near Hilversum, the Netherlands. The complex could be studied in detail, highly facilitated by the excellent and large-scale exposure of the various deposits and soils. OSL dating was used to establish ages of the phases, where possible differentiating between time of deposition and time of burial by taking into account the potential effects of bioturbation. Pollen analysis served to reconstruct the vegetation during the various phases. A first minor phase of aeolian activity already started before approx. 5,000 BC, followed around 4,000 BC by a second phase and a rather massive third phase around 3,000 BC. After a long phase of soil formation, the latest, massive drift sand phase started around the 14th to 15th century. It clearly represents the classic drift sand phase that started in the Late Middle Ages in the Netherlands. Sand drifting followed on soil forming phases during which the vegetation became increasingly dominated by ericaceous plants and culminated in heathlands. The first three aeolian phases and associated heathlands are much older than generally assumed for heathland and drift sand to occur in the Netherlands. Moreover, podzolisation was found to have started very early, true podzols already occurring before 4,000 BC. Around 3,000 BC groundwater in the area reached a maximum altitude of about 230 cm +NAP, resulting in local open water in the area. This rise is probably linked to the development of the Dutch coastal area, where at that time peat accumulated and drainage was poor, inducing a rise of the groundwater level in ‘het Gooi’. This groundwater level fell later on, to never reach this altitude again. The Groot Wasmeer was formed by local stagnation on a slowly permeable podzol and already reached a level of 320-325 cm +NAP by 400 BC, which more or less equals its 20th century level. The results demonstrate that earlier concepts on the occurrence and age of aeolian phases, podzols and heathland vegetations in the Netherlands are far too schematic, and that early, pre-agricultural cultures may already have had an impact on the stability of fragile cover sand landscapes, e.g. through burning. Results are in line with those from several contemporary studies on early prehistoric cultures and their impact in river dune areas in the Central and Eastern Netherlands.

Las zonas más altas de los Andes tropicales del Ecuador albergan frágiles ecosistemas caracterizados por su alta biodiversidad. Estos lugares están habitados por poblaciones indígenas que dependen enteramente para su subsistencia de los recursos naturales de estos sistemas. Los ecosistemas en estas áreas de alta montaña incluyen pajonales de páramo (tropical alpino) y bosques húmedos montanos, que originalmente cubrían grandes extensiones desde Venezuela hasta Perú. Estos ecosistemas cumplen funciones ambientales importantes, como el suministro de agua potable y para irrigación, la conservación de la biodiversidad, el almacenamiento de carbono, la producción agrícola y el turismo. Durante los últimas décadas, la presión de la población sobre los sistemas en cuestión se ha incrementado rápidamente y como consecuencia de ello el uso de la tierra con fines agrícolas se ha extendido, a menudo usando técnicas inapropiadas y conduciendo a una degradación galopante. Los bosques montanos naturales han sido extensamente reemplazados por cultivos de papa o plantaciones forestales (Hofstede et al, 2002), y los páramos naturales son intensamente afectados por el sobrepastoreo y las quemas. En muchas situaciones el uso intensivo de la tierra ha conducido, según se cree, al descenso del límite superior del bosque (UFL, también llamado ecotono bosque-páramo y definido como la zona de transición entre el bosque montano alto y la vegetación de páramo). Sin embargo, movimientos de ascenso del bosque montano han sido atribuidos también al calentamiento global, que afecta particularmente a los ecosistemas de montaña (Price 1999) y severamente complica las predicciones (Castaño 2002). Durante las últimas décadas el Instituto para la Biodiversidad y Dinámica de Ecosistemas (IBED) de la Universidad de Amsterdam ha estado involucrado en la investigación multidisciplinaria de ecosistemas en apoyo a la conservación y al manejo sustentable del bosque altoandino y el páramo, en cooperación con varias organizaciones de la region andina. En dichos proyectos, la información sobre el origen y la ecología de los bosques en el ecotono bosque- páramo es vital para estimar las opciones de uso sustentable de la tierra (agricultura, forestería, conservación). Una solicitud particular por obtener información precisa sobre la dinámica del ecotono bosque- páramo provino de los recientes proyectos de reforestación en ecosistemas altoandinos degradados en Ecuador en el marco del protocolo de Kyoto y su intención de disminuir la emisión de CO2. Un posicionamiento preciso de la altitud natural del UFL en un periodo precedente a la interferencia humana masiva fue necesario para definir la distribución potencial de bosques claves en la restauración ecológica. Sin embargo, la degradación de los bosques naturales, especialmente dentro del valle Central interandino ha tenido lugar por tanto tiempo que la posición natural del UFL a menudo no puede ser establecida directamente, y la investigación paleo-ecológica debe entonces aplicarse imperativamente. Desafortunadamente, ciertos resultados contradictorios del análisis de polen fósil por un lado y del análisis de vegetación por otro lado han dado como resultado la incertidumbre y el debate científico sobre la posición natural del UFL en valle Central interandino del Ecuador. Por ejemplo en la Reserva Biológica Guandera, estimaciones científicas de la posición natural del UFL dieron un rango que va desde la posición actual a 3600 m.s.n.m. hasta una posición hipotética a 4000 m.s.n.m. (Wille et al. 2002, Laegaard 1992). El objetivo principal del programa "Reconstrucción del Límite Superior del Bosque en Ecuador"( Reconstruction of the Upper Forest Line in Ecuador, RUFLE) fue el obtener un mejor entendimiento de la dinámica del UFL en los Andes Ecuatorianos en general, y en particular reconstruir la posición natural más probable en el área de la Reserva Biológica Guandera. Para dilucidar la incertidumbre científica antes mencionada acerca de la posición natural del UFL, se eligió un enfoque multi-proxy para lograr esta meta. En este enfoque una combinación novedosa de técnicas derivadas de la ciencia del suelo, la geoquímica molecular orgánica, la palinología y la ecología vegetal fue puesta en obra para identificar la dinámica del UFL en el espacio y el tiempo a lo largo de cortos transectos altitudinales que cruzan los ecotonos bosque- páramo en la actualidad y en el pasado en el área de estudio. El programa RUFLE fue llevado a cabo en Ecuador y en los Países Bajos en el periodo entre 2004 y 2009 por investigadores de los grupos de investigación en Paleo-ecología y Ecología del Paisaje y del grupo de investigación en Ciencias de la Superficie de la Tierra del Instituto para la Biodiversidad y Dinámica de Ecosistemas (IBED) de la Universidad de Amsterdam, Países Bajos. La investigación fue financiada por la Organización Holandesa para el Avance de la Investigación Tropical (Netherlands Organization for the Advancement of Tropical Research, NWO-WOTRO) y la Universidad de Amsterdam.

In dit rapport worden de resultaten gepresenteerd van een onderzoek uitgevoerd door de Universiteit van Amsterdam naar de verstoring van de bodem in het Koedijk / Gijzenveen gebied, hierna genoemd als Koedijkgebied. Het doel van het inventariseren van de verstoring is tweeledig: 1) in kaart brengen van de locatie en hoeveelheid / mate van verstoring en 2) de verandering in hydrologie na verwijdering van de verstoorde laag.