Abstract Detail

Ecology

Rosburg, Thomas [1].

Spring fire effects on the forb community of a degraded sand prairie.

Big Sand Mound is a unique geological landscape located in southeast Iowa, near the confluence of the Iowa and Mississippi Rivers. The 510-acre site is characterized by sands deposited about 20,000–17,000 years ago. These deposits are associated with the Savanna Terrace, a glaciofluvial landform bordering both sides of the Mississippi River valley from Red Wing, Minnesota south to the confluence with the Ohio River. A cap of aeolian sand accumulated between 17,000–11,500 years ago giving the mound its current form. The site protects diverse ecosystems, including rolling sand prairie, sand barrens, upland and floodplain forests, shallow ponds and marshes. The objectives of this research were: 1) Determine the forb diversity and abundance in a grassland ecosystem at Big Sand Mound. 2) Compare the effect of spring fire on the diversity, abundance and flowering of forbs. 3) Examine the phenology of forb species present in a Big Sand Mound grassland ecosystem. A prescribed burn was conducted on April 7, 2017 in an area that had not been burned for 9 years. The burn was designed to allow for an area to remained unburned. Burn and control plots, each 25x100 m, were established adjacent to one another in May 2017. Eleven 25 m transects were established at 10 m intervals in each plot. Measurements of forb abundance were made along each transect with ten 0.5x2 m quadrats placed at 2.5 m intervals. The data collected from a single transect represented a community sample and a single replicate. Species abundance was measured with absolute frequency in May, July and September. Two sample statistical tests were used to compare species abundance, species reproductive activity, and species richness between control and burn plots. DECORANA ordination was used to examine the variation in species composition among the 6 community samples obtained (3 on each plot). There were 66 plant species observed in the experimental plots. A group of spring-blooming annual species exhibited a clear decrease in abundance due to the fire. The response to fire among other sand prairie forbs was mixed and depended on the species and date. Six species exhibited a decrease, 3 species an increase and 8 species no difference. Reproductive activity of forbs was either compromised or not affected by the spring burn.

1 - Drake University, Biology Dept, Olin Hall, 2507 University Ave, Des Moines, IA, 50311, USA

Keywords:
sand prairie
spring fire
annuals
plant reproduction.

Presentation Type: Oral Paper
Session: 31, Ecology Section - Population Biology
Location: 106/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 4:30 PM
Number: 31012
Abstract ID:880
Candidate for Awards:None