14 research outputs found
História do fogo durante o Holocénico na Serra da Estrela, Portugal: resultados preliminares
Holocene interactions between climate, vegetation, land-use and the fire regime in coastal Southern Sicily: evidences from new sedimentary records
We used a new sedimentary record to reconstruct the Holocene vegetation and fire history of Gorgo
Basso, a coastal lake in south-western Sicily (Italy). Pollen and charcoal data suggest a fire-prone open
grassland near the site until ca 10,000 cal yr BP (8050 cal BC), when Pistacia shrubland expanded and fire
activity declined, probably in response to increased moisture availability. Evergreen Olea europaea woods
expanded ca 8400 to decline abruptly at 8200 cal yr BP, when climatic conditions became drier at other
sites in the Mediterranean region. Around 7000 cal yr BP evergreen broadleaved forests (Quercus ilex,
Quercus suber and O. europaea) expanded at the cost of open communities. The expansion of evergreen
broadleaved forests was associated with a decline of fire and of local Neolithic (Ficus carica–Cerealia
based) agriculture that had initiated ca 500 years earlier. Vegetational, fire and land-use changes ca
7000 cal yr BP were probably caused by increased precipitation that resulted from (insolation-forced)
weakening of the monsoon and Hadley circulation ca 8000–6000 cal yr BP. Low fire activity and dense
coastal evergreen forests persisted until renewed human activity (probably Greek, respectively Roman
colonists) disrupted the forest ca 2700 cal yr BP (750 BC) and 2100 cal yr BP (150 BC) to gain open land
for agriculture. The intense use of fire for this purpose induced the expansion of open maquis, garrigue,
and grassland-prairie environments (with an increasing abundance of the native palm Chamaerops
humilis). Prehistoric land-use phases after the Bronze Age seem synchronous with those at other sites in
southern and central Europe, possibly as a result of climatic forcing. Considering the response of vegetation
to Holocene climatic variability as well as human impact we conclude that under (semi-)natural
conditions evergreen broadleaved Q. ilex–O. europaea (s.l.) forests would still dominate near Gorgo Basso.
However, forecasted climate change and aridification may lead to a situation similar to that before
7000 cal yr BP and thus trigger a rapid collapse of the few relict evergreen broadleaved woodlands in
coastal Sicily and elsewhere in the southern Mediterranean region
Holocene environmental and climatic changes at Gorgo Basso, a coastal lake in southern Sicily, Italy
We used a new sedimentary record to reconstruct the Holocene vegetation and fire history of Gorgo
Basso, a coastal lake in south-western Sicily (Italy). Pollen and charcoal data suggest a fire-prone open
grassland near the site until ca 10,000 cal yr BP (8050 cal BC), when Pistacia shrubland expanded and fire
activity declined, probably in response to increased moisture availability. Evergreen Olea europaea woods
expanded ca 8400 to decline abruptly at 8200 cal yr BP, when climatic conditions became drier at other
sites in the Mediterranean region. Around 7000 cal yr BP evergreen broadleaved forests (Quercus ilex,
Quercus suber and O. europaea) expanded at the cost of open communities. The expansion of evergreen
broadleaved forests was associated with a decline of fire and of local Neolithic (Ficus carica–Cerealia
based) agriculture that had initiated ca 500 years earlier. Vegetational, fire and land-use changes ca
7000 cal yr BP were probably caused by increased precipitation that resulted from (insolation-forced)
weakening of the monsoon and Hadley circulation ca 8000–6000 cal yr BP. Low fire activity and dense
coastal evergreen forests persisted until renewed human activity (probably Greek, respectively Roman
colonists) disrupted the forest ca 2700 cal yr BP (750 BC) and 2100 cal yr BP (150 BC) to gain open land
for agriculture. The intense use of fire for this purpose induced the expansion of open maquis, garrigue,
and grassland-prairie environments (with an increasing abundance of the native palm Chamaerops
humilis). Prehistoric land-use phases after the Bronze Age seem synchronous with those at other sites in
southern and central Europe, possibly as a result of climatic forcing. Considering the response of vegetation
to Holocene climatic variability as well as human impact we conclude that under (semi-)natural
conditions evergreen broadleaved Q. ilex–O. europaea (s.l.) forests would still dominate near Gorgo Basso.
However, forecasted climate change and aridification may lead to a situation similar to that before
7000 cal yr BP and thus trigger a rapid collapse of the few relict evergreen broadleaved woodlands in
coastal Sicily and elsewhere in the southern Mediterranean region
Range-wide population genetic structure of the European bitterling based on microsatellites and mtDNA
Human impact on vegetation at the Alpine tree-line ecotone during the last millennium: lessons from high temporal and palynological resolution
Holocene fish assemblages provide baseline data for the rapidly changing eastern Mediterranean
Chrysocoma ciliata L. (Asteraceae) in the Lesotho Highlands: an anthropogenically introduced invasive or a niche coloniser?
Island biodiversity conservation needs palaeoecology
The discovery and colonization of islands by humans has invariably resulted in their widespread ecological transformation. The
small and isolated populations of many island taxa, and their evolution in the absence of humans and their introduced taxa,
mean that they are particularly vulnerable to human activities. Consequently, even the most degraded islands are a focus for
restoration, eradication, and monitoring programmes to protect the remaining endemic and/or relict populations. Here, we
build a framework that incorporates an assessment of the degree of change from multiple baseline reference periods using
long-term ecological data. The use of multiple reference points may provide information on both the variability of natural systems
and responses to successive waves of cultural transformation of island ecosystems, involving, for example, the alteration
of fire and grazing regimes and the introduction of non-native species. We provide exemplification of how such approaches can
provide valuable information for biodiversity conservation managers of island ecosystems
Holocene palaeo-invasions: the link between pattern, process and scale in invasion ecology?
Invasion ecology has made rapid progress in recent years through synergies with landscape ecology, niche theory, evolutionary ecology and the ecology of climate change. The palaeo-record of Holocene invasions provides a rich but presently underexploited resource in exploring the pattern and process of invasions through time. In this paper, examples from the palaeo-literature are used to illustrate the spread of species through time and space, also revealing how interactions between invader and invaded communities change over the course of an invasion. The main issues addressed are adaptation and plant migration, ecological and evolutionary interactions through time, disturbance history and the landscape ecology of invasive spread. We consider invasions as a continuous variable, which may be influenced by different environmental or ecological variables at different stages of the invasion process, and we use palaeoecological examples to describe how ecological interactions change over the course of an invasion. Finally, the use of palaeoecological information to inform the management of invasions for biodiversity conservation is discussed. © 2008 Springer Science+Business Media B.V