As part of the KPRNA
long-term ecological research (LTER) program, 64 plots (12.
Assessment of soil microbial biomass of our KPRNA
long-term plots showed no significant change in total fungal or bacterial biomass, fungal: bacterial ratios, or microbial carbon and nitrogen after 8 yr of benomyl treatment, although potentially mineralizable carbon and nitrogen and soil respiration were higher in benomyl-treated plots (Smith 1998).
Two sites were at KPRNA on ungrazed upland prairie; one site is burned every 2 yr (2-yr burn site) and the other is burned every 4 yr (4-yr burn site).
Because of these problems, a second, one-season experiment was initiated in 1991 at KPRNA on an annually burned low terrace with relatively deep Florence soil and lacking in obvious vegetation gradients.
The principal disturbance is fire at KPRNA and gopher mounds at NVP (Steuter et al.
In a companion study, we observed that simulated urine patches and the areas immediately surrounding them in a recently burned watershed at KPRNA experienced increased herbivory by bison (Steinauer 1994).
Each row contains one replicate of the same fire frequency treatments as on the KPRNA management units; that is, burning at fixed intervals of every 1, 2, 4, and 20 yr.
The number of times a site was burned between 1972 and 1990, inclusive, was used as a measure of disturbance frequency for the KPRNA management unit data.
Based on multiple regression analysis, species richness on KPRNA management units had a significant negative and linear relationship to burning frequency (adjusted [r.
Changes in species richness during succession were assessed only with the KPRNA management unit data because of a lack of samples from plots burned at intermediate frequencies on the more recent Hulbert plots.