U of M > CBS > Cedar Creek > Research > Data >
Since sweep-net samples give excellent estimates of relative abundance within orders, and good estimates of relative abundance between orders, the main method of sampling the insects in the prairies and savannas was sweep-net. Insects were also collected using pitfalls in some of the prairies and savannas. Once during the growing season ants were sampled using scent plates.
Sweep-net sampling occurred within each field using 100 sweeps per sample.
Pitfall traps were placed at the end of 4 permanently marked transects within the sites sampled. Five scent plates were placed evenly from end to end along the transects, thus providing 20 samples per site. The transects were parallel to each other, 25m apart, and in the prairies 40m long and in the savannas 50m long.
Insects were sampled 7 to 9 times throughout the 1992 growing season. All specimens were manually sorted and identified to species (89.8% of specimens) or morphospecies within known genera or families.
Species biovolume, an index of biomass, was calculated as the average product of length (from tip of head to top of abdomen), width (maximum width of body or head) and thickness (maximum thickness of body or head) for 5 specimens in the oldest life stage for each Orthoptera species. Even though body size increases greatly during development, this method seemed justified since most species (84%) only occurred as adults in the samples taken. To minimize counting a species twice, all larvae were examined by outside experts and, if they might have been the same species as an adult insect, they were counted as a single species.
Voucher specimens were deposited in the Cedar Creek insect collection.
This study included 38 prairies that had developed from fields which had been abandoned from agriculture at various times in the past and 11 savannas. Twenty-two of the prairies that were associated with experiments E014, E054 and E001. One of the savannas was associated with experiment E001. Some of the prairies were periodically burned. All of the savannas had a burn history.
Listing of Site Details
In Current Site Label, P=Prairie and B=Burn Unit. In Last year Cultivated Historical, the years represent the last year of cultivation based on historical documents and interviews of former farmers and/or family members. In Last Year Cultivated Aerial Photographs the years represent estimates of the last year of cultivation based on an historical series of aerial photographs. Pitfall Method and Ant Plate Method columns indicate the sites in which these collection methods were used.
* Helen Allison Savanna is next to, but not within Cedar Creek Natural History Area and is owned by The Nature Conservancy.
| Experiment Site Label | Current Site Label | Ecosystem | Frequency of Burning | Last Year Cultivated Historical | Last Year Cultivated Aerial Photographs | Pitfall Method | Scent Plate Method |
| alo | P29 (E001 Field A) | prairie | not burned | 1968 | post-1960 | Yes | No |
| bb | P21 | prairie | not burned | 1957 | 1957 | Yes | Yes |
| bgn | P24 | prairie | not burned | 1968 | 1975 | Yes | Yes |
| bgs | P26 | prairie | not burned | 1957 | 1958 | Yes | Yes |
| blo | P22 (E001 Field B) | prairie | not burned | 1957 | 1957 | Yes | No |
| blr | P40 | prairie | not burned | 1972 | 1977 | Yes | Yes |
| bls | P41 | prairie | not burned | 1982 | 1977 | Yes | Yes |
| bp | P44 | prairie | not burned | 1961 | 1965 | Yes | Yes |
| bps | P529 | prairie | not burned | 1956 | No | No | |
| cbl | P550 | prairie | not burned | 1943 | Yes | Yes | |
| clo | P69 (E001 Field C) | prairie | not burned | 1934 | 1944 | Yes | No |
| cnw | P32 | prairie | not burned | 1941 | 1943 | Yes | Yes |
| csw | P35 | prairie | not burned | 1941 | 1943 | Yes | Yes |
| dlo | 94 (E001 Field D) (B10 | savanna | 2 years in 3 | Yes | No | ||
| e | P39 | prairie | not burned | 1975 | 1977 | Yes | Yes |
| fc | P47 | prairie | not burned | 1959 | 1957 | Yes | Yes |
| fp | P53 | prairie | not burned | 1961 | 1961 | Yes | Yes |
| gh | P537 | prairie | not burned | 1955 | No | No | |
| gv | P5 | prairie | not burned | 1947 | 1951 | Yes | Yes |
| has | Helen Allison Savanna* | savanna | No | No | |||
| hut | P58 | prairie | not burned | 1950 | Yes | Yes | |
| lbs | P3 | prairie | not burned | 1957 | Yes | Yes | |
| lc | P85 (B108) | prairie | 1 year in 3 | 1956 | Yes | Yes | |
| lem | P61 | prairie | not burned | 1957 | Yes | Yes | |
| mdn | B115 | savanna | 1 year in 2 | No | No | ||
| mds | B116 | savanna | 2 years in 10 | No | No | ||
| mem | P82 (B102) | prairie | 1 year in 3 | 1945 | Yes | Yes | |
| na | P27 | prairie | not burned | 1947 | 1950 | Yes | Yes |
| nc | P548 | prairie | not burned | pre-1938 | Yes | Yes | |
| ncp | P45 | prairie | not burned | 1943 | 1943 | Yes | Yes |
| nwb | B103 | savanna | 9 years in 10 | Yes | Yes | ||
| oms | B117 | savanna | not burned | No | No | ||
| pmn | P67 | prairie | not burned | No | No | ||
| pms | P71 | prairie | not burned | 1957 | Yes | Yes | |
| pot | P72 | prairie | not burned | 1927 | pre-1938 | Yes | Yes |
| rc | P75 (B101) | prairie | 1 year in 2 | 1956 | Yes | Yes | |
| rcb | B101 | savanna | 1 year in 2 | Yes | No | ||
| rse | P84A (B108) | prairie | 1 year in 3 | 1945 | Yes | Yes | |
| rsw | P84 | prairie | not burned | 1962 | Yes | Yes | |
| seb | B104 | savanna | 9 years in 10 | Yes | Yes | ||
| shb | F84 | savanna | wild fire in 1988 | No | No | ||
| sts | P556 | prairie | not burned | 1965 | No | No | |
| sv | P4 | prairie | not burned | 1971 | post-1960 | Yes | Yes |
| swb | B105 | savanna | 1 year in 2 | Yes | Yes | ||
| swe | P77 | prairie | not burned | 1952 | pre-1954 | Yes | Yes |
| sww | P76 | prairie | not burned | 1952 | 1952 | Yes | Yes |
| sys | P70 | prairie | not burned | 1955 | 1951 | Yes | Yes |
| tmg | P80 (B108) | prairie | 1year in 3 | 1956 | Yes | Yes | |
| tms | B108 | savanna | 1 year in 3 | No | No |
