- Seven WATCH assignments fulfilled for the year, another four to go.
Category Archives: Biodiversity and Species Preservation
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.
Richard Conniff is tired of apologizing for protecting wildlife because it’s economically valuable:
Wildlife is and should be useless in the same way art, music, poetry and even sports are useless. They are useless in the sense that they do nothing more than raise our spirits, make us laugh or cry, frighten, disturb and delight us. They connect us not just to what’s weird, different, other, but to a world where we humans do not matter nearly as much as we like to think.
Rick Wright isn’t so sure that blame for the swarms of Sturnus vulgaris that plague the New World can be laid at the feet of a well-meaning 19th-century drug magnate:
Is there any documentation, from [Eugene] Schieffelin or his contemporaries, that the release of starlings in Central Park in 1890 was inspired by a line in Henry IV? I’d be happy to know about it.
Blackburn et al. propose a categorization system to understand the nature and extent of damage caused by non-native species. Their “semi-quantitative” (their word) metric bins species (within a defined area, small or large) into one of five levels of impact, from Minimal (“unlikely to have caused deleterious impacts”) to Massive (“leads to the replacement and local extinction of native species”). They also identify 12 categories of impact, ranging from effects we see frequently in the mid-Atlantic (Competition, Parasitism) to some more obscure ones (Flammability, Bio-fouling).
Good stuff. This is a lot more sophisticated than just tarring everything with the broad brush of “non-native invasive.” And, as the authors point out,
invasiveness… is a characteristic of a population rather than a species.
My 2014-2015 Migratory Bird Hunting and Conservation Stamps (Duck Stamps) arrived in the mail today. Have you bought yours?
A roundup of conservation and natural history links:
- A team at Towson University has launched a microsite and apps (for Android and iOS) for tracking the spread of the highly invasive Wavy-leaf Basketgrass (Oplismenus hirtellus ssp. undulatifolius).
- Janet Fang summarizes a paper by Railsback and Johnson: simulations of coffee plantation activity indicate that 5% land coverage in trees maximizes coffee yields. The overstory of trees reduces the amount of space for coffee shrubs, but it invites birds, who forage on destructive borer beetles.
- Nancy L. Brill describes the survey that a team of entomologists made of invertebrate life in 50 ordinary Raleigh, N.C. homes. The typical house was host to 100 different species of arthropod.
Several families were found in more than 90 percent of homes: gall midges (Cecidomyiidae), ants (Formicidae) and carpet beetles (Dermestidae), along with cobweb spiders (Theridiidae), dark-winged fungus gnats (Sciaridae), cellar spiders (Pholcidae), scuttle flies (Phoridae) and book lice (Liposcelididae). Most houses also had dust mites (Pyroglyphidae).
Pics and interpretation at Arthropods of Our Homes.
- Tovar Cerulli argues that hunters and non-hunters have more in common than they might think.
When clashes occur, it is all too easy to fall back on reductive notions about liberal, elite environmentalists and conservative, redneck hunters—the “greens” versus “the hook-and-bullet crowd.” With partisans on both sides invoking stereotypes and the media portraying hunters and environmentalists as opponents, it is tempting to imagine stark lines between the two.
But such divisions are too simplistic.
- An American Bird Conservancy post makes the connection between coffee farming… and hummingbirds!
- The Birding Wire picked up my profile (for Friends of the Migratory Bird [Duck] Stamp) of Quivira National Wildlife Refuge.
- A leader in Nature highlights a paper by Joshua J. Tewksbury et al., which calls for a revival in the practice of natural history. (I have the Tewksbury paper bookmarked but haven’t read it yet.)
As natural history has been de-emphasized, molecular biology, genetics, experimental biology and ecological modelling have flourished. But here is the problem: many of those fields ultimately rely on data and specimens from natural history….
No biology student should get a diploma without at least a single course in identifying organisms and learning basic techniques for observing and recording data about them.
One helpful side effect of the recent escaped polar vortex: the potential to check invasive insect species in the mid-Atlantic, Northeast, and northern tier states:
“The lethal temperature for the woolly adelgid is minus 4 or 5 degrees Fahrenheit,” said Richard S. Cowles, a scientist with the Connecticut Agricultural Experiment Station, a state research center. “I was cheering a couple of days ago because most of the adelgids will be dying from the temperatures we saw.”
Michael Wines provides a fine update on two different research teams’ efforts to re-establish Castanea dentata to its pre-blight glory. Perhaps the best part of the piece is his concise explanation of the two different mechanisms for fending off Cryphonectria parasitica‘s attack on the chestnut.
Still, it’s too soon to tell whether the genetically modified trees or the Chinese hybrids will be successful.
“We’re only five years in the fields,” [Sara Fern Fitzsimmons of Pennsylvania State University] said. “You can’t really say anything much in forestry until age 15.”
David M. Watson and Matthew Herring present an intriguing open-access paper: it presents the results of a removal experiment, quantifying the striking effect to which mistletoes serve as a keystone resource in Australian forests. The contribution of these parasitic species to leaf litter and the nutrient cycle is one of the factors favoring bird diversity, the authors report.
Hugh Powell reminds us of the connection between wine bottle closures and the preservation of biodiversity. Cork prices are crashing, which threatens cork oak plantations on the Iberian peninsula.
Cork trees live for about 250 years, growing in open groves interspersed with meadows of tawny grasses and diverse wildflowers. Once a decade, skilled workers with hatchets carefully slice off an inch-thick jacket of bark, leaving the tree to grow it back. There are cork farmers right now slicing cork from the same trees that their great, great, great grandparents harvested. In all, some 13 billion corks are produced each year, slightly more than half of them in Portugal and the rest in Spain, France, Italy, Morocco, Algeria, and Tunisia. It’s a $2 billion industry.
The skilled labor pays well, and the farmers can also keep livestock on the land. While they’re at it, the farmers keep a delicate balance in their forests, avoiding overgrazing but keeping shrubs from taking over, setting controlled fires and putting out fierce ones.
Among conservationists there’s a real fear that as cork prices fall, the cork oak forests will deteriorate or be converted into eucalyptus plantations or Mediterranean resorts.
My final writing assignment for my current course, a book report on The Diversity of Life, by E. O. Wilson, is complete.
The hallmark of life is this: a struggle among an immense variety of organisms weighing next to nothing for a vanishingly small amount of energy.—Wilson, pp. 35-36
As a class assignment, I put together a short essay about unattractive habitat and butterfly conservation.
Richard A. Fuller et al. make a provocative proposal in a recent latter to Nature. Working with a data set of the protected areas of Australia, the authors make a quantitative assessment of each preserve’s contribution to conserving vegetation types in the country. They then divide that contribution by the cost of continuing to protect the land (its estimated market value plus management costs), thereby deriving a benefit-cost ratio for each property. Fuller and his team find that about 1% of Australia’s protected areas are not pulling their weight in terms of conserving diversity, and propose that selling these lands (the local term of art is “degazettement”) and using the funds to acquire alternative lands leads to an overall increase in protection with no net impact on public spending.
There are certainly points to argue with in this work. The authors use conservation of vegetation types as their benefit measure, adjusted for the amount of each type found in the protected area and the percentage of each type remaining countrywide since the arrival of Europeans in the mid-eighteenth century. Another measure might yield different results. There are some benefits to protection—a visually attractive viewshed, for instance—that don’t appear to fit into this analysis. Along the same lines of thought, the importance of keystone or indicator species is discounted. If old-growth temperate rain forest is preserved specifically to protect Spotted Owl (Strix occidentalis), there may be knock-on effects. Also, the work assumes that protection can be acquired at market rates, either through outright land purchase or through conservation easements.
Nevertheless, I think it’s a good step toward quantifying the tradeoffs that are an inevitable part of conservation. It’s also worth noting that nearly all the benefit gains are achieved by degazetting the “dogs,” the bottom 1%. Beyond that, the bang (as measured by number of vegetation types protected) doesn’t increase.
Meanwhile, the U.S. federal government is under pressure from the State of Wyoming over two parcels of state-owned land adjacent to Grand Teton National Park, as Bob Beck reports. The high-value properties are held by the state in order to produce revenue, but the lands are yielding little, due to federal restrictions on their use. Wyoming is looking to exchange the land for other lots that can be developed, say for coal mining.
Via Round Robin, something worth a side trip to San Francisco on my next California trip: Maya Lin’s gramophone horn-influenced installation What Is Missing?, a plea for habitat and biodiversity conservation. A short video gives an idea of the experience.