During the long interval of non-blogging, Tess and I have been busy with the rest of the group as we conduct vegetation (veg) surveys around our field site.
Each of us have been pairing off and randomly surveying the vegetation at different randomized points. This has allowed us to get a feel of the different types of habitats here, as well as figure out the ins and outs of the vegetation and structures favored by our beloved red-backed fairy-wrens. Here you’ll find a rough description of what we’ve been up to for the past few days.
- Step 1: Find Random Point
We are each provided with GPS coordinates that will take us to a random computer-generated point. This point could be on a road or a nice plot of short grass…or it could be in 4.5 meter gamba grass on top of a mountain. I guess that’s what makes these surveys exciting and suspenseful…? Sure, we’ll go with that. But seriously, it’s great to go into places we’ve never been and sometimes hear the faint call of a RBFW nearby
- Step 2: Two Minute RBFW Survey and Trek to Actual Veg Point
Once at the point, we stay for two minutes to look and listen for red-backed fairy-wrens. If we hear or see them, we go right to the place we heard/saw them and conduct a vegetation survey there. If not, we walk 100 meters in the bearing that is also randomly generated by a computer next to the GPS point. For instance, if we don’t get a peep from a RBFW at a point near the Lil’ Dam, we might head 100 meters at 270 degrees from the initial point. We determine where 270 degrees is from our fancy compasses, which I always have handy when I do veg points.
- Step 3: Two Minute RBFW Survey and Predator Survey
When we get to our actual veg point, we conduct another two minute RBFW survey. If we hear/see RBFWs from there, we go straight from there to where we saw/heard them (same deal as before). Either way, we follow the two minutes with a one-minute predator survey and look for butcherbirds, Torresian crows, and kookaburras – all potential predators of the RBFW.
- Step 4: Record GPS Point and Set Up Quadrants
At the veg point, we mark the point in our GPS for future reference. We also record the UTMs and elevation that we read from our GPS. We have two 10-meter strings that we lay out in alternating cardinal directions (north, south, east, and west) using our handy-dandy compass. I have my clipboard and mechanical pencil out and ready to record data, while my partner finishes laying out the second string. Both lie at a 90 degree angle and can encompass the northwest, northeast, southeast, or southwest quadrant depending on the compass reading.
- Step 5: Record Data for the First Quadrant (The Nitty-Gritty Stuff)
Once we determine what is inside and outside of the quadrant (particularly focusing on trees), my partner and I both agree on the approximate grass height percentages for the quadrant. For example, a quadrant may have 40% 1.5 meter grass, 20% 1 meter grass, 15% 0.2 meter grass, and 25% bare ground. Then we look for saplings (a.k.a. trees that represent new growth, or baby trees), which can be pretty tricky. Sometimes quadrants have one or two…and other times they have over 100 saplings. After the saplings are accounted for, we focus on the big trees in our quadrant. We qualify trees as woody plants that reach standard breast height, which is about 1.2ish meters. We record diameter at breast height (DBH) for each tree in a quadrant, followed by estimated height. I am almost exactly 1.5 meters, so oftentimes I’m used as a measuring gauge for my partner to estimate height. It’s not uncommon to hear something like, “Yep, that’ll be four Kellys!” I guess being short does have its advantages.
Then we record other structures in our plot, such as log piles or large pieces of old WWII artifacts (after all, our field site used to be an airstrip with acres of surrounding land occupied by Australian military during the war). Log piles are particularly important because RBFWs seem to love them!
- Step 6: Repeat Step 5 for the Other Three Quadrants and Record Densiometer Readings
All the nitty-gritty information is obtained from all four quadrants as we switch strings from north to south and east to west using our compasses. During the string switches, we take a “densiometer” reading at the end of the 10 meter string at each cardinal direction to record tree canopy cover. We either walk five meters out from the center or two meters in from the very end of the ten meter string to use our fancy expensive densitometer (just kidding – they’re actually toilet paper rolls wrapped in duct tape and fluorescent pink flagging tape). We hold it up to the sky straight over our heads and look up through the densitometer and estimate the percentage of tree cover through the roll.
Before finishing, we make sure that we mark if the area was unburned or previously burned, as well as the time and initials of those who conducted the veg survey. We also put pink flagging on a sturdy tree or snag and write on it with sharpie the veg point number, date, and our initials.
- So why is this all important?
We’ll be getting lots of valuable information for habitat availability and variation from all of the work we are doing with these surveys. Also, we’ve recently been taking a purposely biased sample of veg points that are taken where we know we have seen RBFWs previously and right after we spot a RBFW and identify where we first saw him or where he perched the longest. Both types of veg surveys together will give us an idea of habitat usage with the RBFWs on our field site.