Category: Botany

Mixed effects

A recent paper by Jason M. Gleditsch and Tomás A. Carlo explores the impact on nesting success of Gray Catbirds (Dumetella carolinensis) breeding in Pennsylvania landscapes dominated by invasive Asian honeysuckles (Lonicera sp.). It turns out that they found little evidence to support the claim that honeysuckle represents an “ecological trap” of increased predation risk and poor nutritive value from fruits, contrary to the results of other researchers. Adult birds may have made more trips to the nest, bearing what some have called “junk food,” but body mass measurements of the nestlings, in this study, show that they grow up just fine.

Our results show that relationships between introduced fleshy-fruited plants and native birds are complex and not easily characterized as purely harmful or beneficial because they can include negative, neutral, or positive outcomes.

Sometimes, in the authors’ view, using an alien species is the best the birds can do, under the circumstances.

… the traditional and widespread categorical approach to invasive species management should be revised to prevent harming certain communities and ecosystems, especially areas in a process of self-recovery from heavy human disturbances.

Some links: 69

Another post to clear out the inbox:

  • Steven Portugal et al. equipped 14 Bald Ibises (Geronticus eremita) with miniaturized GPS units to study the energetics and aerodynamics of flying in V formation. As the leader summarizes, each bird does indeed time its wingbeats to maximize the drafting effect of following another bird–abstract and heatmaps on the article page.

  • W. R. Grace & Co. has emerged from bankruptcy protection, as Catherine Ho reports.

    I interned for Grace in its New York headquarters in the late 1970s, and then somehow convinced someone at one of its newly-acquired retail businesses, Bermans, the Leather Experts to hire me full-time. (I lasted a year, and the lit out for Washington.) Bermans is long gone, merged into Wilsons and later Georgetown Leather Design, then gradually declining into liquidation in 2008. Back in the 1970s, Grace described its organization as a three-legged stool—specialty chemicals, energy, and consumer retail and restaurants. The energy game was no kinder to the portfolio than brands like Channel home centers and Houlihan’s restaurants. And, as Ho reports, personal-injury lawsuits stemming from asbestos contamination of the company’s vermiculite products sent the company into bankruptcy court.

    My workplace, the soaring building on 42nd Street (with a plaza that extended close enough to Sixth Avenue to give it an Avenue of the Americas address) still stands, but what’s left of the chemicals-only firm is now headquartered in Columbia, Maryland.

  • Brian Hayes uses a rhododendron shrub as a thermometer and wonders at the curled leaves’ apparent piecewise linear response to ambient temperature. Is the curling response a means to curtailing water loss, or a way to minimize UV damage to this understory shrub? Erik Tallak Nilsen likes the latter explanation.

Late to bed

Interesting research from Jason D. Fridley that I may come back to when I take Carole Bergmann’s invasives class in August: Fridley conducted a three-year study comparing congeneric native and non-native shrubs and lianas in the Eastern deciduous forest. The non-natives’ competitive edge didn’t show itself in the spring; both aliens and natives leafed out at about the same time. But the foreign-born Euonymus, Lonicera, Viburnum, and other species dropped their leaves in autumn about a month later than the native woody plants.

Calling all botany geeks

I invite you to participate in the development of a Q&A site for questions about botany. The site would be part of the successful Stack Exchange network, of which Stack Overflow is the flagship.

One of the features of a Stack Exchange site that makes it successful is the liberal awarding of brownie points to users who constructively participate in the site. Jeff Atwood and his team have figured out the alchemy that makes a community-managed site work.

At this point, the proposed Botany site is in the stage of soliciting sample questions. Follow the link below and add your own!

Stack Exchange Q&A site proposal: Botany

Update: The proposal for this Q&A site has been closed, alas.

Winter weeds at Woodend

Five nature fun facts from today’s winter weeds workshop with Stephanie Mason:

  • The generic name for the tickseed sunflowers, Bidens (two-toothed), describes the two-barbed achenes that are typical fruit of the various species.
  • Sensitive Fern (Onoclea sensibilis) is also known as Bead Fern. Look at the spore cases along the fronds in winter to see why.
  • The slender seed pod of Dogbane (Apocynum sp.) looks like a mustard’s silique, but it’s actually a follicle that splits open on one side.
  • Broom Sedge (Andropogon virginicus) is not a sedge, but a grass, and it rather resembles Little Bluestem.
  • A little while ago, I had tumbled to the nomenclatural connection between Cardueline finches and Carduus thistles. But what I didn’t know, as Stephanie explained, is that goldfinches delay breeding into the summer, when thistles are about to set seed. Rather than feeding nestlings insects, as is the norm with songbirds, the parents regurgitate “thistle milk” for their young.