Sunday, June 20, 2010

Christmas in June



Among my favorite activities, crouching over .25 m2 quadrats along a 50 m. transect on a high quality glade while being stung by tiny green bees (legs all laden with pollen) ranks in the Top 3 with floating down an Ozark stream (without cows in it) and setting fire to grassy woodlands. Vegetation monitoring season began last week, and the fulfilled anticipation of discovering species richness in every randomly selected quadrat was energizing, despite the searing sun and hot drinking water stowed in my pack.



Maybe it's luck, or that I design my own projects, that I find myself in such rich sites running transects with average species count per quadrat of 12 or more. Marching down the transect line to the next quadrat, it's hard not to be giddy, hoping that the next quadrat will include that cluster of Talinum calycinum you see ahead or at least one of those tall Kuhnia eupatorioides plants with its burgundy leaves. But, since I choose my own sites wisely, my quadrats always have great plants, no exotics, and total cover values of 50% or more (except when the three sided quadrat tool lands squarely on a huge dolomite boulder that takes up 25% of total cover).


Last week, I returned to the glade we burned in September 2009 to quantify the vegetation responses to a growing season fire versus a March 2009 fire. We set up transects on both sides of the fireline to determine -on a small, localized scale- whether the growing season fire favored forbs or grasses, or if fire seasonality impacted total cover value. Stepping out of the surrounding woodlands onto the glade, the difference between the two sites was obvious; the side burned during the growing season showed robust flowering stems, and the other side had few flowering stems (lots of Houstonia nigricans, but little else). How do you capture that with monitoring data? The Floristic Quality Index (FQI) alone won't filter out blooming plants, and, to boot, the plant composition and total plant density was similar on both sides. The plants blooming on one side were in the matrix on the other side, though in reduced numbers and not in flower. As expected, the spring fire favored grasses. This week, a computer program which will generate percentages of blooms/seeds in each quadrat and average by transect will be completed so the differences between each side of the fireline can be quantified...much better than anecdotal evidence.


We spent two days running transects here, calling out acronyms and cover values and, before setting out for the next quadrat, noting which plants were in bloom or in seed. By Friday, I was sitting in the air-conditioning typing in our quadrat data over the course of an 8 hour day. The reports generated showed a slight difference in species richness and FQI: 53 species/average FQI 5.094 recorded on the side burned during the growing season, and 38 species/average FQI 5.079 on the side of a spring fire. Pulling up data from the area's largest glade complex, long touted as one of the richest sites in the Niangua Basin, native species richness weighed in at 54 species/average FQI 4.981 across all transects. (It should be noted that cattle grazed this glade until the 1980s, and data were last recorded in 2003.)


Furthermore, the glade we sampled last week was used as a dump site for many years. Glass bottles, rusted tin cans, pop tops, and broken glass showed up in most of our quadrats in the growing season fire transects, though no acronym exists for these members of the total cover. Cattle grazing occurred here historically, but when the site became a local dump, the cows were moved to another nearby glade. The response to active management with fire on this old dump site has been remarkable.


For the next two years, a graduate student will be conducting a research project in the area to monitor effects on vegetation of various seasonality of fire on a high quality dolomite glade. As I've written many times before, successful fire regimes must include implementation during different times of the year of varying intensities and unevenly spaced fire return intervals to better mimic naturally occurring events. The growing season fire did not set back this year's flowering plants or destroy the glade as some have suggested, and by the end of the day we all had welts from the various pollinators who gorged on the rich bounty of forbs.

Post scriptum: while combing through files looking for a good Agalinis photo, I found this, the same site in mid-September, 2009:

2 comments:

Hampers said...

Beautiful.... the pictures and words were a joy to see and read... :O)

Allison Vaughn said...

Why thank you, it's that time of year when everything is in bloom. It's hard to stay inside even in this brutal heat...