EarthTrek - Garlic Mustard Field Survey

Method

This is a summary of what you need to do to participate in this project. The Project sheet has all the instructions and a data collection sheet. Become familiar with the project online, and then take the Project Sheet with you into the field. The data will be later logged online.

Locate populations in spring/early summer. The species is easily recognized by its distinctive leaf shape and growth form (see pictures below), as well as a garlic-like odor from crushed leaves. In North America, county weed agents are an excellent source of locality information. In Europe, garlic mustard is a common road-side and understory plant, and is likely to be encountered when driving around most rural areas. Local naturalists are also likely to be able to provide specific information.

Return to each population in mid to late summer, when plants have ripe fruits and most plants have finished flowering. For each population (using copies of the data collection sheet):

Record your name, email address, and the collection date.
Give the population a unique code: your initials and a unique number for each population, as well as a 3-letter code based on the closest town (so if your name is John Doe and you do two populations near New York City, the codes would be JDNYC1 and JDNYC2).
Record latitude and longitude from GPS (use degrees/minutes/seconds format).
Record whether the population is understory, forest edge, roadside, or other (specify)
Estimate population size – Approximate extent of area with garlic mustard in m2 (1m2 = 3.28ft).
Find the widest part of the population (see schematic below). Following a transect line through the center of the population, create the first plot by laying two parallel meter sticks 50 cm (20”) apart, outlining two sides of a 1 m (1 yard) by 50 cm (20”) rectangle. Create the next plot end-to-end with the previous one by moving the meter sticks towards the center of the population. Repeat this until either the other side is reached, or 10 plots have been measured.
Take one good picture of the population that gives a sense of approximate size and average density. Then take three photographs of the forest canopy/sky (i.e. photograph vertically upwards) while standing at the edge (0m), 5m and 10m along the transect. The purpose of sky photos is to quantify shading by trees. At the 5m plot, visually estimate % of open sky (see Project Sheet for examples). If possible, burn photos to a CD or DVD and mail along with the seed samples. Make sure you include the population code in the file name (and ‘0m’, ‘5m’, or ‘10m’ for the canopy pictures ).
In each plot, count the total number of rosettes (juveniles) and adult plants. A rosette is a collection of leaves attached to the same spot on the ground, while an adult plant has a long stem with leaves, flowers or fruits coming out of it. Pictures of a rosette and adult plant are below.
In each plot, beginning at 0 cm and every 20 cm (7.2 inches) thereafter up to 80 cm (1 yard) do the following: (i) Find the rosette closest to either meter stick and measure its diameter. (ii) Find the closest flowering plant, measure its height and count the number of fruits, using a hand-counter. (iii) For the flowering plant, count the number of healthy leaves and the number of leaves with significant herbivory damage (i.e. at least 10% of leaf area damaged). Do not measure the same traits on the same plant twice; if plants are too sparse in a plot to fulfill all measurements, it is OK to have positions on the datasheet blank.
In each population, remove the complete inflorescences (including stem and pods; see figure on the right) of the first 20 adult plants you are measuring, and store them in paper envelopes. Label each envelope with your printed name, and a code that uniquely identifies population, plot and plant position. In small populations, if there < 20 fruiting adult plants along the transect, collect additional inflorescences from unmeasured plants if available.
Label these plants as JDNYC1-x1, JDNYC1-x2, etc.
Keep all seed envelopes together with the datasheet and store in a dry location at room temperature. After drying 1-2 weeks, mail the photos and seeds to the addresses on the Project Sheet.