Category: Biodiversity and Species Preservation

Some links: 70

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.

↬ Leta

Chilly reception

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.”

ᔥ The Morning News

Upcoming: 34

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.”

More than smooches

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.

ᔥ The Economist

Stopper

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.

Swaps

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.

Squeezed in Panama

Elisabeth Rosenthal reports on the controversial findings of Joe Wright, a senior scientist at the Smithsonian Tropical Research Institute in Panama, that the rate of secondary rain forest formation (through abandonment of farms via urbanization, and other causes) is outpacing the rate of primary rain forest destruction. The arguments critical of Wright and those in his support tend to tangle together the function of rain forests as a carbon sink with their role as a refuge for biodiversity.

Regenerated forests in the tropics appear to be especially good at absorbing emissions of carbon, but that ability is based on location and rate of growth. A field abandoned in New York in 1900 will have trees shorter than those growing on a field here [in Central America] that was abandoned just 20 years ago.

For many biologists, a far bigger concern is whether new forests can support the riot of plant and animal species associated with rain forests. Part of the problem is that abandoned farmland is often distant from native rain forest. How does it help Amazonian species threatened by rain-forest destruction in Brazil if secondary forests grow on the outskirts of Panama City?

Here in the East, you can observe the results of old field succession by taking a short drive to the Blue Ridge. Much of the now-protected parkland in the Appalachians was once in agricultural production, as the evidence of a family cemetery in the woods will attest.

Two into one

Via The Economist, recent research published by Evan Preisser and Joseph Elkinton yields an interesting result to those concerned with the conservation of Eastern Hemlock (Tsuga canadensis) trees. From Virginia to Connecticut, the species has been getting clobbered by an invasive hemipteran, Hemlock Woolly Adelgid (Adelges tsugae), native to Asia. However, comes another sap-sucker, Elongate Hemlock Scale (Fiorinia externa), also invasive, to feed on the hemlock. According to the paper, in experimental infestations, trees inoculated with both bug species fare better than those inoculated with just the adelgid.

More conservation tradeoffs

Emma Marris reviews the range of schemes for making choices in conservation biology and even uses the charged word “triage” for Nature‘s 8 November 2007 issue (paywall-protected link).

The EDGE program (Evolutionarily Distinct and Globally Endangered) of the Zoological Society of London gives priority to species that are taxonomically distinct, “far out on their own on the tree of life,” if you will. The reasoning is that a distinct taxon, now endangered, one that branched tens of millions of years ago from the tree, represents a unique chapter of evolutionary history that can’t be rewritten once lost. Priority amphibians include Chinese Giant Salamander (Andrias davidianus) (up to 1.8 meters long!), Sagalla Caecilian (Boulengerula niedeni), a worm-like burrower with an extremely restricted range in Kenya, and Purple Frog (Nasikabatrachus sahyadrensis), only described in 2003; top mammals are Yangtze River dolphin (Lipotes vexillifer) (perhaps already extinct), Long-beaked Echidna (Zaglossus bruijni), and Riverine Rabbit (Bunolagus monticularis) of South Africa. The system doesn’t appear to have been applied to other orders. A paper by Isaac et al., “Mammals on the EDGE: Conservation Priorities Based on Threat and Phylogeny” documents the EDGE metrics as applied to mammals.

The majority opinion among conservation biologists today is that they still understand too little about ecosystem functions to say for sure which species are the ‘load-bearing’ ones whose presence keeps a complex, multi-tiered ecosystem from collapsing into some worst case dull scenario of rats, roaches and invasive grass. “We are so fundamentally ignorant,” says Norman Myers, a fellow of the University of Oxford, UK, and adjunct professor at Duke University in Durham, North Carolina. “We cannot afford, by a long, long way, to say which species are dispensable.”

Thus Myers pioneered the concept of habitat hotspots, and a number of overlapping hotspot maps have proliferated. Birders may be familiar with catalogues of Important Bird Areas, Birdlife International’s Endemic Bird Areas, or Conservation International’s biodiversity hotspots. The problem for conservation biology is that each hotspot schema starts with different assumptions, chief among them the metric that is to be optimized. Do we seek to minimize extinctions of species or taxa, maximize land area preserved, maximize taxonomic diversity, or optimize some other measure? Marris writes that the work of Hugh Possingham of the University of Queensland in this area is getting a lot of attention: Possingham seeks to maximize the number of species conserved (vascular plants and vertebrates, in the paper cited below), trading off against the real-world costs of conservation efforts—land acquisition, invasive predator extirpation on islands, fire management, replanting, what have you. A paper by Kerrie A. Wilson et al., “Conserving Biodiversity Efficiently: What to Do, Where, and When,” explains the methodology and applies it as an example to 17 of the world’s 39 Mediterranean ecoregions.

What I find notable about the paper’s approach are the tools of economic analysis that are brought to bear on the problem. An expenditure in conservation activity is modelled as a financial investment. Different activities (“ecoactions”) show different expenditure streams: compare the one-time cost of land acquisition, for example, to the ongoing cost of fire management. The paper uses standard discounting methods and Net Present Value calculations to make investment choices comparable. The model reflects that the impact on species preservation will show diminishing marginal returns as investment is increased. The investment allocation algorithm is dynamic over time: it accounts for positive effects in the ecosystem as investments are made, and adjusts allocations year by year in response.

Wilson et al. acknowledge that the methodology does not yet account for uncertainty, a keystone of modern financial analysis. Also, it would be fruitful—albeit computationally more complicated—to consider the interaction effects of various conservation activities, rather than assuming that each activity acts independently of others.

A worked example chooses between three ecoactions in the Swan Coastal Plain region of Australia: revegetation to counteract habitat fragmentation, invasive predator control, and management of a soil-borne pseudo-fungus, Phytophthora cinnamomi). Even though Phytophthora management is the most expensive per square kilometer ($514K versus $301K for replanting and $7K for predator control), it is nevertheless the most cost-effective: a marginal $2 million spent controlling the pseudo-fungus, in this computation, will protect 49 species, versus 4 for predator management and effectively zero for revegetation.