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Methods for Experiment 052 -

Animal Sampling Methods

Small mammal trapping in E052 consists of gopher trapping only. This is done the same way as in E001.

Field Operations: Additional notes

On May 5, 1995, a wildfire burned all of the plots in experiment 52 in field B.

Field Operations: Fencing

The plots in experiment E052 are enclosed by a fence to exclude mammalian herbivores. Galvanized welded-wire hardware cloth with 6mm x 6mm openings was buried to a depth of 84cm. Additional hardware cloth extends 60cm above the ground, and poultry netting extends to 1.8m above the ground.

Field Operations: Fertilization

Fertilizer is mixed and spread by hand twice a year, once in early May and once in late June. Each plot gets the fertilizer mixture specified by its fertilizer treatment code

Field Operations: Mammal Trapping

Pocket gophers are trapped out of the fields as soon as they appear. Gopher mounds are then removed and vegetation is unburied.

Field Operations: Neighbor Exclusion

1990: The no neighbors treatment was imposed by severing all roots at the perimeter of a subplot to a depth of 15cm once each sample period. All plants in the subplots were sprayed with a systemic, rapidly decomposing herbicide (Roundup). Any resprouting neighbor biomass was severed at the soil surface and removed by hand. Transplants were grown with only the roots of neighbors by using plastic netting to pull back the shoots (50x50cm;mesh:1x2cm) was fastened to the soil surface at the center of the subplot using four steel pins each 8cm long. The center portion (5x5cm) of the net was cut out to allow transplanting. The outer corners of the net were held 10cm above the soil using pins 20cm long. The all neighbors treatment comprised a transplant grown in the center of a 50x50cm subplot containing the existing, undisturbed vegetation of the plot. See publication: Wilson, S.; Tilman, D.; Plant competition and resource availability in response to disturbance and fertilization. Ecology 74:599-611. 1993 1991:The no neighbor treatment was imposed by driving a tube 10cm deep and 11cm in diameter into the soil and killing all neighbor material inside with Roundup. Each tube was surrounded by garden netting (50 x50cm) to ensure that transplants in no neighbor treatments received an equal and constant amount of light. Transplants in all neighbor treatments also had tubes installed around them in order to make a comparable amount of environmental space available to transplants in both the neighbor and no neighbor treatments.

Field Operations: Rototilling

Rototilling is done in April. Each plot receives the amount of rototilling it should get according to the disturbance treatment each plot is assigned.

Light Penetration

Light meter readings for E052 are taken in the same way as in E001 except that only one set of readings (one above and one below the vegetation) is taken in each plot.

Light Penetration Measurements Methods

From 1982 to 1988, light meter readings were taken using a Li-Cor, Inc. Integrating Quantum/Radiometer/Photometer, model LI-188B. Two people were needed to take light readings with this system. One would hold the control box and record data and the other would hold the light sensor. The batteries would be checked before starting each session. If the batteries were OK, they would proceed to take readings. The sensor was connected to the control box by a relatively short cord, so the two people taking readings were required to stay close together. When taking readings, it was necessary to get a range value for each light value entered. If the integrating time of 1 second was not sufficient, it was increased to 10 seconds. This was also recorded. In 1989, two new light meters were acquired. These are SF Sunfleck Ceptometers, model SF-40 (40cm probe). They were purchased from Decagon Devices, Inc., P.O. Box 835, Pullman, WA 99163. One person can easily handle a ceptometer alone. This makes is possible for three people to get the readings done more quickly and easily. One person records data while the other two take readings from the plots simultaneously. No range values are needed. To take readings a person needs to select function #1 (PAR readings), position the probe (see below) and press ``A' (read value). More than one reading can be taken and then averaged by pressing a certain sequence of letters (A, A, B, B, A). Measurements are taken within a 4 hour period, 2 hours on either side of solar noon. (Solar noon is half way between sunrise and sunset; it is not 1200 hours). Solar noon is at 1315 hours, Central Daylight Time. Samples are taken between 1115 hours and 1515 hours. Measurements are not taken when the plot being sampled is shaded. Light readings are done when the sky is clear, whenever possible. If a cloud passes over the plot being sampled, assistants wait for the cloud to pass before taking the readings. If the sky is mostly cloudy, light meter readings are not taken. Two measurements are taken in each plot. Each measurement consists of one reading above the vegetation and a second reading at ground level. Both values are taken to get the percent of sunlight above the vegetation that reaches ground level. In taking the above vegetation reading, the sensor must be kept level, held high above all vegetation, kept out of the shade (of plants and people) and it must be clean. When taking the below vegetation reading, at ground level, the sensor must be kept level, out of the soil and out of the shade created by people. In 1991, light meter readings were only taken in E026 and E055. Light profiles were taken using an A-shaped frame made of aluminum. Wires were strung across the frame at 10cm intervals. The frame was placed over the subplot being metered. A reading was taken over the top of the frame, and then at each 10cm level, by placing the light meter across the wires, starting at 90cm above the ground. Readings were taken every 10cm down the frame and again at ground level. Light Data Transformations: Light readings are transformed to obtain percent light penetration which represents the percent of light above the vegetation that reaches the ground surface. In cases where the experiment involves shading, another variable is computed to reflect the percent of sun light that reaches above the canopy. This variable is called light available. In the case of absence of artificial shades, the latter is set to 1. percent light penetration = ( Light below canopy / Light above canopy ). percent light available = ( Light below shade / Light above shade ).

Microplot Fertilization Treatments

The "microplot" fertilization treatments are used in experiments 1, 2, 4, 8, 9, 11, 23, 25, and 52. Experiments 5, 6, 28, 36,53,97, 98 and 100 are conducted within plots that are fertilized and should be treated as part of the fertilized plot. There are nine treatment levels, assigned a letter A through I. This is also equivalent to the numeric labels 1 to 9. Treatment levels A through H differ in the amount of NH₄NO₃ added. Treatment I is a true control and receives no nutrients. The nutrients are applied twice a year, once in early May and once in late June. An exception is experiment 25 where time of application is experimentally manipulated. Not all experiments use all possible treatments. Nutrients are given in g/m2 for each fertilization; plot area and treatments used follow the nutrient lists. Treatment A to H receive the following base nutrients:

The description for making trace mineral sand is at the end of this section. The amount of NH₄NO₃ fertilizer added at the different treatment levels is:

These rates are added twice a year. Actual annual N addition is calculated as: 0.34%N * rate (g/m2) * 2 times/year The trace mineral stock solutions are made by adding the following grams of reagent to 1000 ml of water: CuSO4*5H2O 9.8 g ZnSO4*7H2O 22.0 g or ZnCl2 10.5 g CoCl2*6H2O 10.0 g MnCl2*4H2O 180.0 g Na2MoO4*2H2O 6.3 g H3BO3 6.0 g The trace metal solution is made by combining 120ml of each stock solution, adding 67.2g of citric acid dissolved in deionized water and adding deionized water to bring the volume to a total of 2 liters. The working solution is then autoclaved to chelate the trace metals. The size of the plots and treatments used for each experiment are:

Sampling Map

Sampling map for e052 is not currently available 1988: Clipped in the SW corner of each plot, 10cm x 1m 1989: Clipped at 1m in from the right side. 1990: First quadrat was clipped at 1m in from the SW corner of each plot. Each subsequent quadrat was 30cm N from and parallel to the previous quadrat. Vegetation was sampled on May 3, May 22, June 15, July 3, July 24, August 23, September 24 and November 1. Vegetation species composition of all plots was measured on August 22, along a transect that ran diagonally across each plot. Two quadrats, each 0.5 x 1m, were placed along the transect, each 1.5m from one end. The cover of each species was recorded using Daubenmire's scale of six classes. Root biomass was measured in each plot on May 3 and August 23 by taking four soil cores (each 3cm diameter, 10cm deep), evenly spaced along a transect 1m inside the west edge of each plot, and pooling them. The above-ground parts of transplants were harvested during 10-14 Sept. , sorted to dead pieces, flowering tillers and other live portions. All above ground plant material, live and dead, within 15cm of each transplant grown with all neighbors was harvested immediately after the transplant was harvested. 1991: Above-ground biomass was measured by clipping all above-ground plant material within a 10cm x 100cm quadrat in each plot during August 12-16. Four cores were also taken from each plot, combined and rinsed for root biomass. These cores were taken along a transect 1m inside the west edge of each plot. Species composition of all plots was measured on August 13-14 along a transect that ran diagonally across each plot. Two quadrats, each 0.5 x 1m, were placed along the transect, each 1.5m from one end. The cover of each species was recorded using Daubenmire's scale of six classes (Mueller-Dombois and Ellenberg 1974). Transplants were harvested during September 9-12 by removing the tubes which contained the transplants. Transplant and neighbor biomass were determined. 1993: Starting at the SE corner, we measured 2m north and 1m west. Then, sample was clipped in a quadrat 1m long and 10cm wide running west from their point. (See sheet for 1993).

Treatment layout : trmte52

Vegetation Sampling Methods

E052 is in field B. Plots in this experiment are sampled on an annual basis. Each time it is sampled, the sample strip is located in a different place. Documentation on where the strips are located for each year can be found in the clipping maps. Species composition of all plots was measured on August 22, 1990 along a transect that ran diagonally across each plot. Two quadrats were placed along the transect, each 1.5m towards the center of the plot from each end of the transect. Thus, there were two quadrats per plot. The cover of each species was recorded using Daubenmire's scale (Mueller-Dombois and Ellenberg 1974). Standing crop was measured by clipping all aboveground plant material within a 10cm x 1m quadrat in each of the ten plots used for the competition experiment. Different quadrats were clipped in each plot on May 3, May 22, June 15, July 3, July 24, August 23, September 24 and November 1, 1990. The first quadrat was 1m inside the SW corner of each plot, and each subsequent quadrat was 30cm N from, and parallel to, the previous quadrat. Sampling methods are the same as described in above ground vegetation sampling methods except for the use of a meter stick instead of the 3m aluminum pole because the sample strips are only 1m long.

abxe052 - Field B Microplot Arthropod Sweepnet Sampling

Field B Arthropod Sweepnet Sampling

This experiment is based in Field B in an 8 x 13 grid of plots adjacent to e001. See the main E052 web page and the page labeled ?methods for e052? for experimental treatment descriptions and other information. Insects were swept in all plots in 19/Aug/1998, 25/June/1999, 19/August/2000, 20/June/2001, 19/Aug/2001. Plots were swept by John Haarstad, with 1-2 helpers in 1998 and 1999. Likely 25 sweeps were taken in each plot (an assumption by C.Satyshur based on methods used in e120 and the e001 Field C microplots). A sweep consisted of a rapid approximately 2m-long horizontal swing of the net through the vegetation. Sweeps were transferred to plastic bags and frozen. Arthropods in frozen samples were sorted to genus or species, sometimes to morphospecies. When Tetrastichus (Hymenoptera: Eulophidae) occurred in large numbers they were estimated to the nearest 10. Identification and sorting was done by John Haarstad.

Field B Arthropod Sweepnet Sampling: Data Preparation

Data preparation was begun by John Haarstad, who entered data into excel and assigned Arnett codes. Data preparation was completed by Colleen Satyshur, who matched Arnett codes in raw data with those in a Master Code File provided with data by John. Information in the Master Code file was checked against the raw data taxonomic information and clarified using the Access code database created by Stephanie Pimm Lyon and John Haarstad for e120 in 2007. *Note about comparing experiments: morphological notes may not indicate the same species/group in different experiments.

rbse052 - Schizachyrium scoparium seedling root and shoot biomass

Schizachyrium scoparium seedling root and shoot biomass

During 25-27 April we measured the length of each leaf on each seedling. Fifty seedlings were harvested, dried, and weighed, and the relationship between the sum of leaf lengths (in millimetres) and aboveground biomass (in grams) was used to determine the initial aboveground biomass of each seedling (BIOMASS = 0.0000659(TOTAL LEAF LENGTH) - 0.00476, r2 = 0.78, P < .01). The third of the remaining seedlings most similar in biomass were selected and transplanted into the field experiment. The aboveground biomass of transplanted seedlings at the start of the experiment was 0.025 ?0.0063 g (mean ? 1 so). See: Wilson, S.; Tilman, D.; Plant competition and resource availability in response to disturbance and fertilization. Ecology 74:599-611. 1993