Effects of long-term consumer manipulations on invasion in oak savanna communities

Ecology ◽  
2009 ◽  
Vol 90 (5) ◽  
pp. 1356-1365 ◽  
Author(s):  
Eric W. Seabloom ◽  
Elizabeth T. Borer ◽  
Burl A. Martin ◽  
John L. Orrock
Keyword(s):  
Oak Savanna ◽  
Savanna Communities

scholarly journals Ten years of pulling: Ecosystem recovery after long‐term weed management in Garry oak savanna

2019 ◽  
Vol 1 (10) ◽  
Author(s):  
Nancy Shackelford ◽  
Sean M. Murray ◽  
Joseph R. Bennett ◽  
Patrick L. Lilley ◽  
Brian M. Starzomski ◽  
...  
Keyword(s):  
Weed Management ◽  
Oak Savanna ◽  
Ecosystem Recovery

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.

scholarly journals Demography of evergreen and deciduous oaks in a mixed oak savanna: insights from a long‐term experiment

Ecosphere ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Frank W. Davis ◽  
Claudia M. Tyler ◽  
Bruce E. Mahall
Keyword(s):  
Oak Savanna ◽  
Term Experiment ◽  
Long Term Experiment

scholarly journals Influence of Climate on Oak Savanna Tree Species in the Midwestern United States

2020 ◽  
pp. 7-23
Author(s):  
Isaac Hayford ◽  
Sophan Chhin
Keyword(s):  
Acer Rubrum ◽  
Oak Savanna ◽  
Quercus Alba ◽  
Black Cherry ◽  
Red Maple ◽  
White Oak ◽  
Temperature And Precipitation ◽  
Open Canopy ◽  
Potential Impact ◽  
Savanna Communities

Aims: The previously abundant high quality and open canopy oak savanna communities in the Midwest have been reduced by more than 98% of their pre-settlement (pre-1840) area because of changing land use and represent some of the most threatened ecosystems in North America. Prior knowledge of oak savanna communities’ climatic resilience to potential impact of climate change and competition is critical to restoration success.  This study examined sensitivity to climatic stress, and effects of competition, which are important considerations during oak savanna restoration. Methodology: Dendrochronological methods were used to sample oak savanna communities located in MacCready Reserve (MR) situated in southern Michigan, U.S.A. The influence of climate (mainly temperature and precipitation) on white oak (Quercus alba L.), red maple (Acer rubrum L), and black cherry (Prunus serotina Ehrh) were correlated using dendroclimatic techniques. The effect of competitor species (A. rubrum and P. serotina) on Q. alba were examined using competitor ratio chronologies and examining correlations with climatic variables. Results: Findings indicate that precipitation in winter, spring, and summer is beneficial for radial growth of white oak. White oak is more resilient to drought stress than red maple and black cherry due to its ecophysiological adaptations but tends to grow rather slower when in competition with shade tolerant and fire sensitive competitor species. Conclusion: Overall, this study has shown that temperature and precipitation play key roles in tree productivity and thus climatic sensitivity should be incorporated in the restoration of oak savanna ecosystems.

Short-term and Long-term Effects of Burning on Oak Savanna Arthropods

1997 ◽  
Vol 137 (2) ◽  
pp. 349 ◽  
Author(s):  
Evan Siemann ◽  
John Haarstad ◽  
David Tilman
Keyword(s):  
Oak Savanna ◽  
Long Term Effects ◽  
Short Term

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

2020 ◽  
Author(s):  
Matthew Trumper ◽  
Daniel Griffin ◽  
Sarah E. Hobbie ◽  
Ian 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. A single fire event often increases short-term nitrogen (N) availability to individual plants, but repeated burning causes ecosystem carbon and 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 leveraged one of the longest running prescribed burn experiments (established in 1964) to evaluate how fire frequency and changing vegetation composition influenced wood stable N isotopes (δ15N) across space and time. 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 in 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 burned in four of every five 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 have declined over time in all burned stands, but at a rate proportional to fire frequency. We found that wood δ15N records within each stand were remarkably coherent in their mean state and trend through time. A gradual, temporally synchronous 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.

Therapy and prevention for mental health: What if mental diseases are mostly not brain disorders?

2019 ◽  
Vol 42 ◽  
Author(s):  
John P. A. Ioannidis
Keyword(s):  
Mental Health ◽  
Mental Disease ◽  
Brain Disorders ◽  
Social Stressors ◽  
Labor Education ◽  
Mental Diseases ◽  
Long Term Follow Up ◽  
Political Decisions

AbstractNeurobiology-based interventions for mental diseases and searches for useful biomarkers of treatment response have largely failed. Clinical trials should assess interventions related to environmental and social stressors, with long-term follow-up; social rather than biological endpoints; personalized outcomes; and suitable cluster, adaptive, and n-of-1 designs. Labor, education, financial, and other social/political decisions should be evaluated for their impacts on mental disease.

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