Sökning: "vegetation dynamics"

Visar resultat 6 - 10 av 107 avhandlingar innehållade orden vegetation dynamics.

1. 6. Northern Permafrost Region Soil Carbon Dynamics since the Last Glacial Maximum : a terrestrial component in the glacial to interglacial carbon cycle

   Författare :Amelie Lindgren; Gustaf Hugelius; Peter Kuhry; Fortunat Joos; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Soil organic carbon; Permafrost; Peat; Loess; Vegetation; Biome reconstruction; Last Glacial Maximum; Deglaciation; Glacial-interglacial cycle; Carbon cycle; Physical Geography; naturgeografi;

   Sammanfattning : At the Last Glacial Maximum (LGM), after ~100,000 years of relatively cold temperatures and progressively lower atmospheric carbon dioxide (CO2) concentrations, CO2 levels reached ~180 ppm, which is less than half of what we see today in a much warmer world (~400 ppm). Although much of this increase since the LGM is due to human-induced emissions, about 100 ppm of this increase can be attributed to natural variations seen over glacial to interglacial cycles. LÄS MER

3. 7. Holocene dynamics in subarctic peat plateaus of west-central Canada : Vegetation succession, peat accumulation and permafrost history

   Författare :A. Britta K. Sannel; Peter Kuhry; Peter Jansson; Ian Brown; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; peatlands; permafrost; carbon accumulation; fire; subarctic; Holocene; Physical geography; Naturgeografi;

   Sammanfattning : Dynamics in vegetation, permafrost and peat and net carbon accumulation rates throughout the Holocene have been studied in two subarctic peat plateaus of west-central Canada through plant macrofossil analysis, geochemical analyses and AMS radiocarbon dating. Peatland formation at the studied sites began around 6600-5900 cal yr BP as a result of paludification of upland forests. LÄS MER

4. 8. Long-lasting ecological legacies of reindeer on tundra vegetation

   Författare :Dagmar D. Egelkraut; Johan Olofsson; Bruce Forbes; Hans Tømmervik; René van der Wal; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Alternative stable state; Herbivory; Historical contingency; Nutrient cycling; Plant-herbivore interactions; Plant-soil feedbacks; Rangifer tarandus; Reindeer herding; Traditional land use; Tundra vegetation;

   Sammanfattning : Reindeer can have strong effects on the plant species composition and functioning of tundra ecosystems, and often promote a transition towards a graminoid-dominated vegetation type. As a result, they influence many ecological processes, such as nutrient dynamics, soil biotic composition and functioning, and carbon storage. LÄS MER

5. 9. Grow with the flow : Hydrological controls of riparian vegetation in boreal stream networks

   Författare :Lenka Kuglerová; Roland Jansson; Hjalmar Laudon; Birgitta Malm-Renöfält; John Stella; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; boreal forest; channelization; groundwater; Krycklan catchment; liverworts; mosses; riparian buffers; riparian vegetation; river restoration; species richness; stream network; stream size; vascular plants;

   Sammanfattning : What drives species diversity across landscapes is one of the most fundamental questions in ecology. Further, understanding the mechanisms underlying species diversity patterns is important not only for forming and challenging ecological theories but also essential for appropriate landscape management and effective nature conservation. LÄS MER

7. 10. Atmospheric dynamics and the hydrologic cycle in warm climates

   Författare :Henrik Carlson; Rodrigo Caballero; Johan Nilsson; Jonathan L. Mitchell; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; superrotation; early Eocene; warm climates; Madden-Julian Oscillation; the hydrologic cycle; vegetation sensitivity; large-scale circulation; atmosfärvetenskap och oceanografi; Atmospheric Sciences and Oceanography;

   Sammanfattning : Past warm climates represent one extreme of Earth's known climate states. Here, we study warm climates in both idealized simulations and full-complexity general circulation model (GCM) simulations of the early Eocene epoch, approximately 50 million years ago. LÄS MER