Long-term patterns of shrub expansion in a C4 -dominated grassland: fire frequency and the dynamics of shrub cover and abundance

2003 ◽  
Vol 90 (3) ◽  
pp. 423-428 ◽  
Author(s):  
Jana L. Heisler ◽  
John M. Briggs ◽  
Alan K. Knapp
Keyword(s):  
Fire Frequency ◽  
Shrub Cover ◽  
Shrub Expansion ◽  
Grassland Fire

Shrub cover in northern Nunavik: can herbivores limit shrub expansion?

Polar Biology ◽  
2014 ◽  
Vol 37 (5) ◽  
pp. 611-619 ◽  
Author(s):  
Sabrina Plante ◽  
Emilie Champagne ◽  
Pascale Ropars ◽  
Stéphane Boudreau ◽  
Esther Lévesque ◽  
...  
Keyword(s):  
Shrub Cover ◽  
Shrub Expansion

scholarly journals Resilience of the boreal forest in response to Holocene fire-frequency changes assessed by pollen diversity and population dynamics

2010 ◽  
Vol 19 (8) ◽  
pp. 1026 ◽  
Author(s):  
Christopher Carcaillet ◽  
Pierre J. H. Richard ◽  
Yves Bergeron ◽  
Bianca Fréchette ◽  
Adam A. Ali
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Frequency Control ◽  
Regional Scale ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Frequency Changes ◽  
Fire Intervals ◽  
In Fire

The hypothesis that changes in fire frequency control the long-term dynamics of boreal forests is tested on the basis of paleodata. Sites with different wildfire histories at the regional scale should exhibit different vegetation trajectories. Mean fire intervals and vegetation reconstructions are based respectively on sedimentary charcoal and pollen from two small lakes, one in the Mixedwood boreal forests and the second in the Coniferous boreal forests. The pollen-inferred vegetation exhibits different trajectories of boreal forest dynamics after afforestation, whereas mean fire intervals have no significant or a delayed impact on the pollen data, either in terms of diversity or trajectories. These boreal forests appear resilient to changes in fire regimes, although subtle modifications can be highlighted. Vegetation compositions have converged during the last 1200 years with the decrease in mean fire intervals, owing to an increasing abundance of boreal species at the southern site (Mixedwood), whereas changes are less pronounced at the northern site (Coniferous). Although wildfire is a natural property of boreal ecosystems, this study does not support the hypothesis that changes in mean fire intervals are the key process controlling long-term vegetation transformation. Fluctuations in mean fire intervals alone do not explain the historical and current distribution of vegetation, but they may have accelerated the climatic process of borealisation, likely resulting from orbital forcing.

scholarly journals The response of cerambycid beetles (Coleoptera: Cerambycidae) to long-term fire frequency regimes in subtropical eucalypt forest

2019 ◽  
Vol 44 (4) ◽  
pp. 609-620 ◽  
Author(s):  
Martyn Eliott ◽  
Simon Lawson ◽  
Andrew Hayes ◽  
Valerie Debuse ◽  
Alan York ◽  
...  
Keyword(s):  
Fire Frequency ◽  
Eucalypt Forest ◽  
Cerambycid Beetles

Determinants of fire activity during the last 3500 yr at a wildland—urban interface, Alberta, Canada

2016 ◽  
Vol 86 (3) ◽  
pp. 247-259 ◽  
Author(s):  
Emma L. Davis ◽  
Colin J. Courtney Mustaphi ◽  
Amber Gall ◽  
Michael F.J. Pisaric ◽  
Jesse C. Vermaire ◽  
...  
Keyword(s):  
Tree Ring ◽  
Management Practices ◽  
Vegetation History ◽  
Fire Regime ◽  
Fire Suppression ◽  
Fire Frequency ◽  
Sources Of Information ◽  
Fire Activity ◽  
Historical Range

AbstractLong-term records of wildfires and their controlling factors are important sources of information for informing land management practices. Here, dendrochronology and lake sediment analyses are used to develop a 3500-yr fire and vegetation history for a montane forest in Jasper National Park, Alberta, Canada. The tree-ring record (AD 1771-2012) indicates that this region historically experienced a mixed-severity fire regime, and that effective fire suppression excluded widespread fire events from the study area during the 20th century. A sediment core collected from Little Trefoil Lake, located near the Jasper townsite, is analyzed for subfossil pollen and macroscopic charcoal (>150 μm). When comparing the tree-ring record to the 3500-yr record of sediment-derived fire events, only high-severity fires are represented in the charcoal record. Comparisons between the charcoal record and historical climate and pollen data indicate that climate and vegetation composition have been important controls on the fire regime for most of the last 3500 yr. Although fire frequency is presently within the historical range of variability, the fire return interval of the last 150 yr is longer than expected given modern climate and vegetation conditions, indicating that humans have become the main control on fire activity around Little Trefoil Lake.

scholarly journals Late-Quaternary Vegetational and Climatic History of the Yellowstone/Grand Teton Region

1988 ◽  
Vol 12 ◽  
pp. 189-192
Author(s):  
Cathy Barnosky
Keyword(s):  
Environmental History ◽  
Late Quaternary ◽  
Sediment Cores ◽  
Sediment Accumulation ◽  
Fire Frequency ◽  
Ice Age ◽  
Sediment Chemistry ◽  
History Of ◽  
Climatic History

The research underway has focused on two different aspects of the environmental history of the Yellowstone/Grand Teton region. One objective has been to examine the long-term vegetational and climatic history of Jackson Hole, the Pinyon Peak Highlands, and Yellowstone Park since the end of late Pinedale glaciation, about 14,000 years ago. Fossil pollen in sediment cores from lakes in the region is being analyzed to clarify the nature and composition of ice-age refugia, the rate and direction of plant migrations in the initial stages of reforestation, and the long-term stability of postglacial communities. Sedimentary charcoal also is being examined to reconstruct fire frequency during different climatic regions and different vegetation types in the past. This information is necessary to assess the sensitivity of plant communities to environmental change and to understand postglacial landscapes of the northern rocky Mountains. The second objective has been a multidisciplinary investigation of the relationship of climate to sedimentation rates in lakes and ponds in Yellowstone, undertaken with Drs. Wright, D.R. Engstrom and S.C. Fritz of the University of Minnesota. This facet of the research examines the relative importance of climate, fire, hillslope erosion induced by overgrazing, and nutrient enrichment in the last 150 years, as recorded in selected lakes in the northern range of Yellowstone. Populations of elk and bison are known to have fluctuated greatly during this interval, and slight climatic changes are suggested from other lines of research. In this study pollen, diatoms, charcoal, sediment chemistry, and sediment accumulation rates are analyzed in short cores from small lakes.

scholarly journals Postglacial Fire Frequency and its Relation to Long Term Vegetational and Climatic Changes in Yellowstone Park

1991 ◽  
Vol 15 ◽  
pp. 276-279
Author(s):  
Cathy Whitlock ◽  
Sarah Millspaugh
Keyword(s):  
Environmental Change ◽  
Climate Changes ◽  
Fire Frequency ◽  
Climatic Changes ◽  
Term Effect ◽  
Environmental Perturbations ◽  
Long Term Effect ◽  
Primary Agent ◽  
Pollen Records

The paleoecologic record provides unique insights into the response of coinmunities to environmental perturbations of different duration and intensity. Climate is a primary agent of environmental change and its long-term effect on the vegetation of the Yellowstone region is revealed in a network of pollen records. Fire frequency is controlled by climate, and as climate changes so too does the importance of fire in shaping and maintaining spatia\l patterns of vegetation. The prehistoric record of Yellowstone's northern range, for example, shows the response of vegetation to an absence of major fires in the last 150 years (Whitlock et al. 1991; Engstrom et al. 1991). In longer records spanning the last 14,000 year8, periods of frequent fires are suggested • by sediments containing high percentages of fire-adapted trees and high amounts of charcoal (Bamosky et al. 1987).

scholarly journals Century-scale wood nitrogen isotope trajectories from an oak savanna with variable fire frequencies

2020 ◽  
Vol 17 (18) ◽  
pp. 4509-4522
Author(s):  
Matthew L. Trumper ◽  
Daniel Griffin ◽  
Sarah E. Hobbie ◽  
Ian M. Howard ◽  
David M. Nelson ◽  
...  
Keyword(s):  
20Th Century ◽  
Prescribed Burning ◽  
Fire Frequency ◽  
Oak Savanna ◽  
N Availability ◽  
Net N Mineralization ◽  
Vegetation Composition ◽  
Prescribed Burn ◽  
Decadal Scale

Abstract. Fire frequency exerts a fundamental control on productivity and nutrient cycling in savanna ecosystems. Individual fires often increase short-term nitrogen (N) availability to plants, but repeated burning causes ecosystem N losses and can ultimately decrease soil organic matter and N availability. However, these effects remain poorly understood due to limited long-term biogeochemical data. Here, we evaluate how fire frequency and changing vegetation composition influenced wood stable N isotopes (δ15N) across space and time at one of the longest running prescribed burn experiments in the world (established in 1964). We developed multiple δ15N records across a burn frequency gradient from precisely dated Quercus macrocarpa tree rings in an oak savanna at Cedar Creek Ecosystem Science Reserve, Minnesota, USA. Sixteen trees were sampled across four treatment stands that varied with respect to the temporal onset of burning and burn frequency but were consistent in overstory species representation, soil characteristics, and topography. Burn frequency ranged from an unburned control stand to a high-fire-frequency stand that had burned in 4 of every 5 years during the past 55 years. Because N stocks and net N mineralization rates are currently lowest in frequently burned stands, we hypothesized that wood δ15N trajectories would decline through time in all burned stands, but at a rate proportional to the fire frequency. We found that wood δ15N records within each stand were remarkably coherent in their mean state and trend through time. A gradual decline in wood δ15N occurred in the mid-20th century in the no-, low-, and medium-fire stands, whereas there was no trend in the high-fire stand. The decline in the three stands did not systematically coincide with the onset of prescribed burning. Thus, we found limited evidence for variation in wood δ15N that could be attributed directly to long-term fire frequency in this prescribed burn experiment in temperate oak savanna. Our wood δ15N results may instead reflect decadal-scale changes in vegetation composition and abundance due to early- to mid-20th-century fire suppression.

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