by Sandy Garland
Yes, it’s about dog-strangling vine (DSV) again, our major preoccupation at the Fletcher Wildlife Garden. We’re making a bit of progress in some areas and noting that many native species (like walnut trees, goldenrods, and raspberries) are holding their own or even out-competing DSV. But there are places where DSV is so thick and robust, nothing else is growing with it.
This Tuesday (August 4), we welcomed another new volunteer, Louisa. After introducing Melanie, Kate, Ted, and Mirko, we decided to try different approaches. Some of us would work on the area I call the pine woods. In 1995, Fisher highschool students planted a couple of dozen white pine saplings just north of the original Old Woodlot. They are now about 8 metres tall and form a dark grove with lots of pine needles on the ground under them.
DSV has continued to grow around these trees despite repeated efforts to pull it out and mulch around the trees. Last fall a wonderful team of Carleton students pulled all DSV from the area and put it into bags to keep the seeds from spreading. The area looked so different (bare) and so ready for change that I decided to make a special effort to keep DSV from growing back.
Over the last year, I’ve been slowly digging out DSV roots and planting native species, like Large-leaved Aster, Sarsaparilla, Canada Mayflower, and sedges. Derek scythed the area at the end of June, and each of these efforts makes a visible difference. Today, we decided to see how much DSV we could dig out in one afternoon.
Meanwhile, super-volunteers Mirko and Melanie offered to continue scything the worst field in terms of DSV infestation – the one north of the woods where we are also trying to establish a large patch of Common Milkweeds (see Emily Pollington – conservation superstar).
This was Melanie’s first try at scything, but, like everything else she has attempted, she mastered the skill in no time. Quite frankly, I had no hope that she and Mirko would make inroads into the huge, tough DSV vines in the middle of that field, but an hour and a half later, my jaw dropped when I went to have a look. They had carefully cut DSV along the east side of the Red Osier Dogwood shrubs and White Pines and then moved out into the middle of the DSV stand. We can now see grass still trying to grow in that field, and, with a bit of work, we should be able to plant a couple of our butternut trees there next week. Huge difference!!
Meanwhile, Kate, Louisa, and I managed to dig up about 8 square metres of DSV under those pine trees. I’m thinking about all the Jack-in-the-Pulpit seedlings I grew this spring and will search our nursery for other appropriate woodland wildflowers for that location. Big changes!!
|Flora, fauna, and ?
Just as Kate, Louisa, and I were getting shovels out to start digging DSV, a black moth caught our eye. A closer look revealed an interesting looking creature with yellow antennae and orange patches on its wings. Kate guess a clearwing, and we reached for our cameras to get photos for later ID. That evening, Kate sent me this photo and triumphantly proclaimed Albuna fraxini – Virginia Creeper Clearwing. And she couldn’t help reporting that this species has “boring larvae,” i.e., the larvae bore into their woody host plants.
Another great find was not one, but two liverworts growing in one of our DSV-free circles just north of the woods and across the trail from our pine woods patch. The one at the left is a thallose species – it produces flat green lobes very close to the ground with a texture that looks a bit like liver. The one on the right (below) is a leafy species that I thought was a moss, but Kate recognized immediately as another liverwort. Those tiny leaves are about 1 mm long; they grow in two rows along a “stem” unlike mosses, whose “leaves” grow in whorls around the stem. The reason for all the quotation marks is because liverworts have no veins, so these names of vascular plant parts don’t really apply to them.
Liverworts belong in the Bryophyte family with mosses, and like mosses have gametophytes and sporophytes. What you see in the photos are gametophytes, haploid forms that produce gametes (male and female). I don’t think it’s possible to tell whether these are male or female gametophytes unless they grow the little stalked structures in which eggs and sperm form (archegonia and antheridia, respectively). The sperm cells can swim, but need water to help them reach the archegonia, where they fertilize eggs to form sporophytes, which are the diploid stage of the species. There’s a much more detailed description of the life cycle and a helpful diagram on Wikipedia under Marchantiophyta.