Search Results

You are looking at 1 - 2 of 2 items for

  • Author or Editor: J. Cahill x
  • Refine by Access: All Content x
Clear All Modify Search

Similarity between seed bank and aboveground vegetation is frequently studied in order to better understand how community composition is affected by factors such as disturbance and succession. Grassland plant communities are known to be sensitive to shifts in precipitation and increases in temperature associated with climate change, but we do not know if and how these factors interact to affect the similarity between seed bank and aboveground vegetation. Also unknown is how the impact of grazing, the dominant land-use in grasslands, will interact with climatic conditions to affect similarity. We manipulated precipitation and temperature, and cut vegetation (as a proxy for grazing) at a grassland site for three years. Percent cover of aboveground vegetation was estimated in the third year, and compared with persistent seed bank samples taken in the year prior from the same plots. Similarity increased with reduced precipitation, was unresponsive to warming, and decreased with clipping. The aboveground community responded strongly to the treatments, while the seed bank community did less so, suggesting similarity responses were largely driven by changes in aboveground vegetation. Because of the importance of the seed bank in vegetation regeneration, understanding the relationship between seed bank and aboveground vegetation will improve our understanding of plant community dynamics under climate change and varied management (grazing) intensities.

Restricted access

Abstract  

Utilizing primarily instrumental neutron activation analysis (INAA) and other analytical methods as many as 61 elements were quantitatively surveyed in 170 U.S. whole coals, 70 washed coals, and 40 bench samples. Data on areal and vertical distributions in various regions were obtained along with extensive information on the mode of occurrence of various elements in the coal matrix itself.

Restricted access