Tuesday, July 23, 2013

No complexity-stability relationship in natural communities - Cornell University Library

No complexity-stability relationship in natural communities

We performed a stability analysis of 119 quantitative food webs which were compiled using a standard methodology to build Ecopath mass-balance models. Our analysis reveals that classic descriptors of complexity do not affect stability in natural food webs. Food web structure, which is non-random in real communities, reflects another form of complexity that we found influences dramatically the stability of real communities. We conclude that the occurrence of complex communities in nature is possible owing to their trophic structure.
Comments:Main text: 9 pages, 4 figures. Supplementary Information: 14 pages, 3 figures
Subjects:Populations and Evolution (q-bio.PE)
Cite as:arXiv:1307.5364 [q-bio.PE]
 (or arXiv:1307.5364v1 [q-bio.PE] for this version)


Submission history

From: Dominique Gravel [view email]
[v1] Sat, 20 Jul 2013 01:51:27 GMT (362kb,D)

Sunday, July 14, 2013

Yokohama squash - Not Every New Plant is Invasive

Gregory Yokohama squash - USDA ARS NAL "Special Collections"

               Thomas Jefferson wrote that "the greatest service which can be rendered any country is to add an useful plant to it's culture...."[1] He could hardly imagine the unintended consequence and impact that the introduction of non indigenous species has had on the ecosystems and economies of the United States. The spread of invasive species alters ecosystem services and threaten rare and endangered species; second only to land development practices in their destructive impact. It is easy, therefore, to condemn the actions of past generations who worked hard to find new and novel species to enhance the quality of life of their fellow citizens.

               Jefferson noted that the United States were "probably far from possessing, as yet, all the articles of culture [crops] for which nature has fitted our country. To find out these, will require an abundance of unsuccessful experiments. But if, in a multitude of these, we make one or two useful acquisitions, it repays our trouble."[2] Those whom have had to fight kudzu or tamarisk might take umbrage and even be outraged at the idea that the introduced species that did not find merit were paid for.

               The US Department o Agricultural Research Service (USDA ARS) was established in part to foster Jefferson's idea that "[t]he introduction of new cultures [crops], and especially of objects [plants] of leading importance to our comfort, is certainly worthy the attention of every government, and nothing short of the actual experiment should discourage an essay of which an hope can be entertained."[3]

               Because of the significant harm of a few intentionally or accidentally introduced plants, certain stakeholders have taken a dim view to non-native plants and to those who introduced them to the United States. This tendency to lump all exotic plants into one basket is based on part on a limited view of history and the role of the men who introduced important non-native species such as wheat and vegetables. Only 150 years ago, men such as Thomas Hogg, Jr. and James J. H. Gregory worked to better the produce of our farms and gardens sure in the knowledge that they were contributing to the betterment of the country and its people.

               An 1866 article in The Cultivator & Country Gentleman provides an example of a then recent introduction of a new winter squash from Japan.

" THE YOKOHAMA SQUASH Eds Co Gent The past summer we raised Yokohama Squash and it has given such good satisfaction both as a table squash and for pies that think its merits need only to be known in order it may be appreciated The vines of this new visitor from Japan slowly till some time in July when they spread rapidly on every side taking root at almost every joint and throwing out numerous side branches so that when planted eight feet apart the entire ground is occupied by the dark green leaves while the numerous peculiar looking squashes are thickly hidden beneath them I find that they yielded with us the past season from 20 to 30 squashes to the square rod averaging four or five pounds each They are very heavy in proportion to their size the seeds being small and contained in a very small cavity The flesh is very dry sweet fine grained and of a rich orange color When cooked they make the best substitute for sweet potatoes of anything I know of and for pies I think them equal to any other squash They ripened here in Connecticut the past season but required the entire season in order to mature before frost The keep very well but 1 think not quite as well as Hubbard The stems of the Yokohama where they join the squash are nearly square a peculiarity never saw in any other squash I have no seeds spare as they are already disposed of G. F. P. Milford, Conn Feb 7 1866."[4]

William Woys Weaver (2005) describes the squash as a "oddly shaped squash that resembled large chunks of hardened lava. Gray-black, other-worldly, yet hauntingly beautiful, this unique heirloom vegetable from Japan, the ‘Yokohama’ squash, was a visual study in the Japanese affection for serenity through form and texture. [The Yokohama squash has] one of the most complex flavors I have run across in any squash or pumpkin I have grown. Everyone’s taste buds are different, but I detect hints of Asian pear, mango, avocado, lemon balsam, and if you have experience with tropical fruits, the unmistakable aroma of sapote. Can this be a squash? It is even a great boon to gardeners because it is highly resistant to borers and powdery mildew."[5]

               Who were Hogg and Gregory? Thomas Hogg, Jr. was born in London, February 6, 1820, coming to the United States with his father, Thomas Hogg, Sr. and his brother James when he was 9 months old. His father was a successful nurseryman and florist in New York City. He and his brother took over the business when their father diedin I855. A staunch liberal, progressive Republican, Thomas Hogg, Jr. was appointed U. S. Marshall in 1862 by President Lincoln, who also founded USDA and sent to Japan for eight years. He would return thereafter for two more years at a posting in the Custom House. He spent much time in travelling around the Japanese Islands studying their flora since his official position afforded him unusual facilities for exploration and collection of novel and interesting plant species and cultivars. He made a large collection of Japanese trees, shrubs and herbaceous plants "among those which proved to be adapted to our climate, are many of the choicest Japanese plants which ornament our gardens to-day, which he was the first to introduce."[6]  

               James Hogg grew the seeds sent from Japan by his brother reporting the "outcome in an 1864 issue of The Magazine of Horticulture. Hogg named the variety "Yokohama" and said it was superior to the Hubbard types which were at the time the standard in American gardens."[7] James Hogg  sent seeds of the Yokohama squash to the noted Massachusetts  plantsman, James John Howard Gregory. Mr. Gregory advertised the new squash in 1865 in Marblehead.[8]    

               I was delighted to find an original copy of the handbill advertising the Yokohama squash while compiling an inventory of pre-1870 nursery catalogs in the Special Collection of the U. S. National Agricultural Library. (USDA ARS NAL)

[1] Thomas Jefferson Memorandum of Services to My Country, after 2 September 1800  PTJ, 32:124. Polygraph copy at the Library of Congress.

[2] Letter from Thomas Jefferson to William Drayton (1786). Thomas Jefferson Agricultural Institute http://www.jeffersoninstitute.org/initiative/jefferson.shtml

[3] Letter from Thomas Jefferson to M. Lasteyrie (1808) Thomas Jefferson Agricultural Institute. http://www.jeffersoninstitute.org/initiative/jefferson.shtml- (In other words, test the new crop before assuming it has nothing to offer.)

 [4] The Cultivator & Country Gentleman, Volume 27 L. Tucker & Son, 1866.

[5] Weaver. 2005. Yokohama Squash. Online. Accessed July 14, 2013. http://www.motherearthnews.com/real-food/yokohama-squash.aspx#axzz2Z2JTu6GK

[6] Morong, T. (1893). Thomas Hogg. Bulletin of the Torrey Botanical Club, 20(5), 217–218. doi:10.2307/2477496
Author's npte: Kudzu, which he sent to Thomas Meehan, noted nuseryman in Philadelphia in 1876, not withstanding...

[7] Baker Creek Heirloom Seed Company. Online. Accessed July 14, 2013. https://www.facebook.com/permalink.php?story_fbid=165630743551869&id=155935376162

[8] Shari Kelley Worrell & Norma Lovett Gregory Kelley Flude. A Timeline of his life.  Online. Accessed July 14, 2013. http://www.saveseeds.org/biography/gregory/
Mr. Gregory purchased the rights to the "best white potato" for $150 from Luther Burbank.  Mr. Gregory introduced a new potato that he shared with Luther Burbank calling it "Burbank".