Sedgwick Reserve

28 Apr, 11 AM - 30 Apr, 07 AM

Arbuscular mycorrhizal fungi are an ancient group of fungi that form a symbiotic association with most plant species. Through this symbiosis, AM fungi play critical roles in terrestrial plant ecology. While most work has focused on the importance of the mycorrhizal association in plant ecological processes, individual species of AM fungi are also known to vary in ecologically important ways. Our ability to characterize AM fungal diversity and composition and to test its importance is hampered by our rudimentary understanding of taxonomic diversity. We estimate that at least 80% of AM fungal species remain undescribed. We will advance our understanding of fungal taxonomic diversity by exploring community composition and species distribution in native grasslands of North America. Native grasslands in North America have been highly disturbed due to agriculture and overgrazing, and as a result, high-quality, undisturbed grasslands are very rare. We sample in a manner which allows us to estimate the biodiversity of AM fungi present in native grasslands and then compare it to the biodiversity of AM fungi in the old fields and degraded lands which have replaced the native grasslands. In particular, we sample multiple sites within each of four grassland systems: Tallgrass prairie, shortgrass prairie, desert grasslands and California grasslands. At each site, we measure AM fungal diversity using both traditional morphological and molecular genetic markers. We will also isolate, culture and describe fungal species. DESCRIPTION OF RESEARCH The objective is to document the diversity of arbuscular mycorrhizal fungi of grasslands and their relationship with the plant community and agricultural disturbance. To this end, we will survey the plant communities and sample the AM fungal communities across grasslands of the US, including the Santa Rosa Plateau. Plant sampling will be non destructive (with small samples occasionally taken for species identification). Fungal sampling will necessitate soil collection via cores. Sampling Design At each site, we sample the plant and AM fungal diversity associated with remnant grasslands and nearby disturbed or degraded grasslands. We will identify high quality areas and the disturbed sites in cooperation with reserve managers. We will then identify five sample points at random within the high quality and degraded categories. At each of these points, we will establish a one meter square permanent plot, with a 1/4 meter square plot nested within the Northeast corner, in which we will determine the plant and AM fungal composition. With these plots we will have direct measures of plant and fungal diversity at two scales, and resampling measures can be used to estimate the diversity at larger scales. Vegetation sampling We measure the plant community during the peak of the growing season. At each plot, plant cover will be estimated using the point-intercept method (Barbour et al. 1999). We will use a meter x meter frame to collect 60 data points within the 1/4 subplot and 150 grid points over the remainder of the plot. A pin will be inserted into the vegetation canopy at each of the grid points and all individuals of each species touched by the pin will be identified and counted. Any plant species present in the plot, but not intercepting a pin, also will be recorded. These data will provide a measure of plant species richness, evenness, and diversity at two scales for each of the plots. Plant species will be identified using regional floras. Characterization of the AM Fungal Community We will assess the diversity of AM fungi in each of our sites by integrating direct observations of field-collected spores, pot cultures designed to trap and induce fungi to sporulate, and rDNA sequences from field-collected roots. Each site will be sampled during two seasons. We sample when host plants are at peak growth to target active mycorrhizal hyphae in proliferating roots. These samples will be used for molecular characterization of the AM fungal community and for establishment of trap pot cultures. We sample sites again at the end of the growing season after fungi have sporulated to identify field spores Sampling of soil. During the growing season, three 5 cm-diameter cores up to 45 cm deep will be collected at uniform intervals within the ? meter sq plot. Six additional cores will be dispersed throughout the rest of the plot. Cores from the ? m sq subplot will be pooled separately from the cores from the rest of the plots. The pooled samples will be mixed and a subsample of fresh roots (ca 1 g fresh weight) will be collected, transported on ice overnight to the lab at IU, and stored at -80?C until DNA analysis. Remaining soil samples will be divided into two parts and transported on ice to IU for establishment of trap cultures and preliminary analysis of spores. Size and location of study area We need to sample high quality remnants as well as post-agricultural old fields or overgrazed heavily-invaded grasslands. In each of these areas, we would establish five 1 m2 quadrants to which we may return over the next two years. We will seek advise from reserve managers of Sedgwick Reserve in identifying appropriate locations. Given that our plant survey is non destructive and our soil samples are small, we expect the environmental impact to be minimal.

Visit #15152 @Sedgwick Reserve

Approved

Under Project # 7027 | Research

AMF Biodiversity

faculty - Indiana University

Reservation Members(s)

James Bever Apr 28 - 30, 2008 (3 days)
James Bever Apr 28 - 30, 2008 (3 days)

Reserve Resources(s) | Create Invoice

Studio Apartment 2 Apr 28 - 30, 2008