The snow shows us shapes and textures we might otherwise overlook.
“Darwin pointed out that ‘many plant parts, and particularly leaves, move in response to a number of extrinsic (environmental) and intrinsic (physiological) factors. The most important extrinsic factors are light intensity (phototropic), light direction (heliotropic), water content (hydrotropic), and temperature (thermotropic). The most frequently observed case of thermotropic movements occurs in plants in hot, dry environments where leaves move upward and become vertical to avoid excessive light absorption. The thermotropic leaf movements of Rhododendron are unusual because these movements are in response to cold temperatures and the leaves become pendent rather than vertical.’”Nilsen summarizes the various theories about thermotropic leaf movements in rhododendrons, describes his own research, and concludes that “the thermotropic leaf curling in Rhododendron may serve to prevent damage to cellular membranes during the process of daily rethawing that often occurs during the early morning.”It’s an interesting, readable article.
“It was the humble carrier-pigeon that was to prove the only means of breaking the blockade in reverse. A microphotography unit was set up in Tours, and there government despatches were reduced to a minute size, printed on feathery collodion membranes, so that one pigeon could carry up to 40,000 despatches, equivalent to the contents of a complete book. On reaching Paris, the despatches were projected by magic lantern, their contents transcribed by a battery of clerks. During the siege, 302 pigeons were sent off, of which 59 actually reached Paris. The remainder were taken by birds of prey, died of cold and hunger, or ended up in Prussian pies. As a counter-measure, the Prussians imported falcons, which prompted one of the many imaginative Parisian 'inventors' to suggest that the pigeons be equipped with whistles to frighten off the predators. When the war finally ended, there was talk of rewarding the noble birds (which some compared to the savior geese of Ancient Rome) by the incorporation of a pigeon in the city’s coat of arms.” (Horne, p. 256)
[Researchers] constructed a model that related bird abundance and species richness to home prices. The model suggests that the presence of less-common birds helps home prices soar. On a lot that already had one less-common species, for instance, the addition of a second such species improved mean home prices by $32,028.Here’s the article, followed by the abstract from the original study.
An innovative study of home sales in Lubbock, Texas, suggests that planners can use relatively simple bird counts to analyze the ecological and economic values of urban landscapes. And it finds that even a single extra species can help pinpoint relatively rich ecosystems.
“A problem urban ecologists and ‘new urbanists’ often face is the difficult task of completing ecological-environmental evaluations in a timely and cost-effective fashion,” write Michael C. Farmer and colleagues at Texas Tech University, Lubbock, in Urban Ecosystems. As a result, officials in a rush to issue permits often deem all green spaces, such as public parks, beneficial—even though ecologists know “that not all green spaces are equally valuable.”
The researchers decided to see whether bird surveys might offer a quick-and-dirty solution. They collected information on approximately 368 home sales in 17 Lubbock neighborhoods from 2008 to 2009. Then they conducted bird counts in the vicinity of each home sale, recording both the total number of birds and the number of “less-ubiquitous” species—which included blue jays and western kingbirds. They also used Google Earth to estimate the percentage of tree cover in the area surrounding each sale. Finally, [researchers] constructed a model that related bird abundance and species richness to home prices.
The model suggests that the presence of less-common birds helps home prices soar. On a lot that already had one less-common species, for instance, the addition of a second such species improved mean home prices by $32,028. Although that number shouldn’t “be taken too literally,” it does suggest that the presence of less-common birds indicates a varied ecosystem—such as one with a variety of trees and shrubs. That’s in line with ecological studies showing that more diverse bird life tends to inhabit ecosystems with more “vertical” diversity (vegetation of various heights).
“This deliberately simple and inexpensive indicator,” they conclude, could help ecologists and economists identify development practices that provide “even stronger gains to housing values, environmental footprint, and urban wildlife that might otherwise go unnoticed in a quick-paced development cycle.”
Abstract: It is known that public greenspaces contribute positively to urban home prices; yet urban ecologists also have known that not all greenspaces are equally valuable. Also some ecologically valuable space appears on private residences, not only public spaces. This work examines directly whether using a variable derived from bird species richness and relative abundance adds new information regarding ecological value and if high values of that variable significantly improve urban housing prices. We collected information on approximately 368 home sales in Lubbock, TX from 2008 to 2009 from the Multiple Listing Service: Sale Price, Square Footage, Lot Size and Age in 17 neighborhoods identified by the Lubbock Realtor Association. We conducted bird counts in the vicinity of each home sale and recorded both the total numbers of birds and the number of bird species identified in a particular class—less ubiquitous bird species. Finally, we used GIS to record the percentage of tree cover in the immediate area surrounding each sale. We constructed a predictive model for a bird relative abundance and species richness variable (Bird) from AICc statistics. Home price for each sale then was regressed against the predicted value of ‘Bird’ from the selected model and regressed against home price along with other attributes from the Multiple Listing Service. The predicted value for Bird finds that the addition of another desirable, less ubiquitous bird species improves mean home price by $32,028, likely due to the human created landscapes on private properties immediately surrounding a home sale. Curiously, the presence of a nearby park neither explained variation in the ecological indicator nor contributed to home price elevation. This deliberately simple and inexpensive indicator helped to direct attention to the composition of local landscapes in specific areas to assess joint ecological and economic gains rather than presume a priori that open greenspace jointly satisfies these dual objectives.
―Charles Dickens (1812-1870), A Tale of Two Cities (1859, opening of Chapter III, “The Night Shadows”)