St. James Farm, Lately

by Carl Strang

This has been a relatively slow winter at St. James Farm Forest Preserve. There has been little snow, so my tracking has been limited. Coyotes have been covering the preserve, and the relatively few deer tracks have not revealed a consistent pattern. That in itself suggests buck group, and eventually in January I saw them: a huge buck, a good-sized but clearly subordinate forkhorn, and a newly minted buck fawn. Since that first sighting, I have spotted them twice more in widely separated parts of the preserve.

The boss buck

The boss buck

As I mentioned in an earlier post, the great horned owls’ nest tree of last winter was a casualty of the autumn’s controlled burn. My practice is to wait until mid-February to do the annual nest search. I had my inventory of candidate cavities, made last winter, but it didn’t take long to find the incubating female on last year’s red-tailed hawk nest. In a related note, I spotted a newly available candidate cavity along one of my monitoring routes. The top of an old oak recently broke off, leaving an open top of sufficient diameter that great horneds might consider it. A forest this old probably has some equilibrium of candidate cavities as old ones are lost and new ones form.

The new candidate nesting cavity

The new candidate nesting cavity

With that task out of the way, I decided to see if I could find a little nest in the area where the hooded warbler had his territory last summer. He has been a regular there in recent years, but as far as I know, no one has seen a female or young. I found that his territory has scattered bush honeysuckles and lots of Japanese barberries, bad for forest quality but probably good from the warbler’s viewpoint. Descriptions of hooded warbler nesting suggest that barberry would be an ideal platform. I didn’t find a nest, and ended the search when I found a dense thicket of barberries, with a few multiflora roses mixed in, at least 100 feet in diameter, worthy of Brer Rabbit.

 Part of the thorny tangle

Part of the thorny tangle

As I circumnavigated this patch, which is in a part of the forest with relatively dramatic surface relief, I noticed a few tipped trees whose fall had turned up rounded stones in the soil.

Rounded stones exposed by a tipped tree’s root tangle

Rounded stones exposed by a tipped tree’s root tangle

This suggests that the preserve’s forested hills may in fact be kames, places within the melting continental glacier where the meltwater piled its flow-rounded stones into mounds. St. James Farm is very close to the western edge of the Valparaiso Moraine.

 

Literature Review: Vines

by Carl Strang

Here’s a word for you: liana. It’s ecologist-speak for “vine.” Hey, why limit yourself to one syllable when you can use three? Still, I think it’s a beautiful word. This week I want to highlight a study of temperate zone lianas published last year (Ladwig, Laura M., and Scott J. Meiners. 2010. Spatiotemporal dynamics of lianas during 50 years of succession to temperate forest. Ecology 91:671-680).

Poison ivy is a vine, though it doesn’t always look like it. Sometimes it grows along the ground, sending up shoots that look like separate plants.

Ecologists associate lianas mainly with tropical forests, where they are an important component of the plant community. They climb the tree trunks and occupy a significant place in the canopy. Lots of species. Lots. So, it was refreshing to see a study of vines in the temperate zone, specifically, New Jersey.

These researchers looked at data from a long-established study area, asking how vines fared at different times as abandoned fields succeeded to mature forests. In addition to poison ivy, dominant vine species were Virginia creeper, grapes, and Japanese honeysuckle. The combined liana cover peaked mid-succession (20-30 years post-abandonment). At that point the area was in an herbaceous stage with the vines climbing scattered trees and shrubs or growing over the ground. As the trees grew, became dominant, and closed the canopy, the liana cover decreased but the number of vine plants continued to increase so that small suppressed individuals were well placed to take advantage of openings. At least, that was the strategy taken by most species.

Grapes were the exceptional lianas in this study.

Grapes were exceptional, increasing their coverage more as canopies closed. Living successfully up in the canopy, the grape tops made them late successional while the other 3 dominant species were early successional. Thus, grapes were the closest lianas to the classic tropical idea for this group.

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