Global Warming Studies at KAEFS

Two experiments related to global warming have been conducted on KAEFS. The first, long-term experiment consists of 6 sets of paired plots, half of which have been warmed 2 °C above ambient since November, 1999. Nested in this design are clipped plots that mimic one of the dominant land uses of the KAEFS region, hay mowing.

pic1

These studies have shown that these grassland systems are remarkably resilient, with little change in community structure as a result of warming. However, a number of microbial processes have shown significant changes, with increased rates of decomposition, and alterations in rates of soil respiration. Litter decomposition was highest in the unclipped warmed and clipped plots. Clipped plots are significantly drier, slowing rates of microbial processes.

pic2pic3pic4

Production of warm season (C4) grasses is higher in warmed plots due to the lengthened growing season. Frost occurs later in the fall, so the C4 grasses, particularly Little Bluestem (Schizachyrium scoparium) can grow for a longer period of time. Cool season (C3) plants are less affected with the exception of the highly allergenic species, Ragweed (Ambrosia psilostachya).

pic5

The red bars are the flowering period for plants in warmed plots and the blue bars are the flowering period for plants in control plots. Note how plots that normally flower before peak summer heating (vertical dashed line) flower earlier with warming and plants that flower after peak summer heating, flower later with warming.
From Wan et al. 2005. Global Change Biology, vol 19.

pic6

Tags: 

  • Current