Daniel H. Janzen Explained

Daniel H. Janzen
Birth Name:Daniel Hunt Janzen
Birth Date:1939 1, mf=yes
Birth Place:Milwaukee, Wisconsin
Known For:Tropical ecology, biodiversity development
Work Institutions:University of Pennsylvania, Guanacaste Dry Forest Conservation Fund, Área de Conservación Guanacaste (ACG)
Alma Mater:University of Minnesota, University of California, Berkeley
Prizes:Kyoto Prize
Spouse:Winifred Hallwachs

Daniel Hunt Janzen (born January 18, 1939, in Milwaukee, Wisconsin) is an American evolutionary ecologist and conservationist. He divides his time between his professorship in biology at the University of Pennsylvania, where he is the DiMaura Professor of Conservation Biology, and his research and field work in Costa Rica.

Janzen and his wife Winifred Hallwachs have catalogued the biodiversity of Costa Rica. Through a DNA barcoding initiative, Janzen and geneticist Paul Hebert have registered over 500,000 specimens representing more than 45,000 species, which has led to the identification of cryptic species of near-identical appearance that differ in terms of genetics and ecological niche. Janzen and Hallwachs developed some of the most influential hypotheses in ecology that continue to influence research more than 50 years later. Janzen and Hallwachs helped to establish the Area de Conservación Guanacaste World Heritage Site, one of the oldest, largest and most successful habitat restoration projects in the world.

Early life and education

Daniel Hunt Janzen was born January 18, 1939, in Milwaukee, Wisconsin.[1] His father, Daniel Hugo Janzen,[2] grew up in a Mennonite farming community and served as Director of the United States Fish and Wildlife Service.[1] His father and mother, Miss Floyd Clark Foster of Greenville, South Carolina, were married on April 29, 1937.[3]

Janzen obtained his B.Sc. degree in biology from the University of Minnesota in 1961, and his Ph.D. from the University of California, Berkeley in 1965.

Career

In 1963, Janzen attended a two-month course in tropical biology taught in several field sites throughout Costa Rica. This Advanced Science Seminar in Tropical Biology was the precursor to a Fundamentals in Tropical Biology course, which Janzen designed for the Organization for Tropical Studies (OTS), a consortium of several North American and Costa Rican universities. Janzen went back in 1965 as an instructor and has lectured in at least one of the three yearly courses every year since.[4]

Janzen taught at the University of Kansas (1965–1968), the University of Chicago (1969–1972), and the University of Michigan (1972–1976) before joining the faculty at the University of Pennsylvania.[5] There he is the DiMaura Professor of Conservation Biology, and his research and field work in Costa Rica.[6]

Janzen has also held teaching positions in Venezuela (Universidad de Oriente, Cumaná in 1965–66; Universidad de los Los Andes, Mérida in 1973), and in Puerto Rico (Universidad de Puerto Rico, Río Piedras, 1969).[7]

Research

Janzen's early work focused on the careful and meticulous documentation of species in Costa Rica, and in particular on ecological processes and the dynamics and evolution of animal-plant interactions.[4] In 1967, for example he described the phenological specialization of bee-pollinated species of Bignoniaceae,[8] amongst them a "kind of mass flowering", which Alwyn Howard Gentry in his classification of flowering named Type 4 or "big bang" strategy.[9] Janzen proposed many hypotheses that inspired decades of work by tropical and temperate ecologists (see below).

Miguel Altieri in his textbook Agroecology: The Science of Sustainable Agriculture says: "Janzen's 1973 article on tropical agroecosystems was the first widely read evaluation of why tropical agricultural systems might function differently from those of the temperate zones".[10] [11]

In 1985, realizing that the area in which they worked was threatened, Janzen and Hallwachs expanded the focus of their work to include tropical forest restoration, expansion (through land purchases) and conservation.[12] They employed the help of local Costa Ricans, converting their farming skills into parataxonomy, a term they coined in the late 1980s.[13] As of 2017, some 10,000 new species in the Area de Conservacion Guanacaste have been identified thanks to the efforts of parataxonomists.

Through a DNA barcoding initiative with geneticist Paul Hebert, they have registered over 500,000 specimens representing more than 45,000 species, which has led to the identification of cryptic species of near-identical appearance that differ in terms of genetics and ecological niche.[14] [15] [16] Janzen and Hallwachs have supported species barcoding initiatives at both national and international levels through the Instituto Nacional de Biodiversidad (INBio), CBOL (Consortium for the Barcode of Life) and iBOL (International Barcode of Life).[17] [18] [19]

Influential hypotheses

Janzen is known for proposing "characteristically imaginative and unorthodox" hypotheses.[20] These hypotheses have received varying degrees of support,[21] but are notable for having inspired a large and sustained body of research, as evidenced by the extremely high citation rates of many of his papers for decades after they are published.

One of Janzen's most famous ideas (from his most highly cited paper)[22] is now known as the Janzen-Connell hypothesis, as Janzen and Joseph Connell independently proposed the idea in 1970-1971. They both suggested that the high diversity of tropical trees was due, in part, to specialist enemies attacking seeds or seedlings that were particularly close to the parent tree or particularly densely clustered, thus preventing any one species from becoming dominant.[23]

Another influential idea[24] comes from Janzen's 1967 paper 'Why mountain passes are higher in the tropics'.[25] It proposes that tropical mountains are more of a barrier to species dispersal than temperate mountains because tropical species are less able to tolerate changes in temperature with elevation, having evolved and lived in relatively stable climates.

In a 1977 paper 'Why fruits rot, seeds mould, and meat spoils',[26] Janzen proposed that microbes render food inedible (or at least distasteful) to vertebrates not just as a by product of microbe-microbe competition or accidental waste products, but as an evolutionary strategy to repel vertebrates consumers, who would otherwise eat the food resource and the microbes themselves. Evidence is mixed, and it is hard to test whether compounds evolved to deter other microbes or vertebrates,[27] but the idea has been widely incorporated into studies of vertebrate feeding from humans[28] to dinosaurs.[29]

Coevolution of plants and animals

Tropical habitat restoration

Tropical dry forests are the world's most threatened forest ecosystems. In middle America there were 550 000 km2 of dry forests at the beginning of the 16th century; today, less than 0.08% (440 km2) remains.[31] They have been cleared, burnt and replaced by pastures for cattle raising,[32] at an ever-faster rate during the last 500 years.[31]

In 1985, realizing that widespread development in northwestern Costa Rica was rapidly decimating the forest in which they conducted their research, Janzen and Hallwachs expanded the focus of their work. Janzen and his wife helped to establish the Area de Conservación Guanacaste World Heritage Site (ACG), one of the oldest, largest and most successful habitat restoration projects in the world. They began with the Parque Nacional Santa Rosa, which included 100km2 of pasture and relictual neotropical dry forest and 230km2 of marine habitat.[12] This eventually became the Área de Conservación Guanacaste, located just south of the Costa Rica-Nicaragua border, between the Pacific Ocean and the Cordillera de Tilaran which integrated four different national parks. Together these house at least 15 different biotopes, viz (mangroves, dry forest and shrubs, ephemeral, rainy season, and permanent streams, fresh water and littoral swamps, evergreen rain- and cloud forests...) and ca. 4% from world's plant, mammals, birds, reptiles, amphibians, fishes and insects diversity, all within an area less than 169000ha.[33] It is one of the oldest, largest and most successful habitat restoration projects in the world. As of 2019, it consists of 169000ha.[33] The park exemplifies their beliefs about how a park should be run. It is known as a center of biological research, forest restoration and community outreach.[14]

Habitat restoration is not a simple matter. Not only must one fight against hundreds of years of ecological degradation, manifested in the form of altered drainage patterns, hard to eradicate pastures, compacted soils, exhausted seed banks, diminished adult and propagule stocks, proliferation of fire-resistant and unpalatable weeds from the old world tropics and sub-tropics.[34] Also one is faced with the difficulties of changing a culture which coevolved with, profited from and can become miserable with such a system.[35] [36] [37]

For this reason ACG was conceived as a cultural restoration project, which, to paraphrase its natural counterpart, ought to be grown as well. ACG integrates complementary processes of experimentation, habitat restoration and cultural development.[38] The techniques used include:

Personal life

Janzen is married to ecologist Winifred Hallwachs, who is also his frequent research partner. Of Hallwachs, Janzen has said, "We did these things together," and "we are very much together in perceiving things the same things....Since I'm the vocal member, it's then attributed to me. But I would say these ideas and directions and thoughts and actions are easily fifty-fifty attributable."

Honorary distinctions

Janzen has been subject to recognition many times in the US, as well as in Europe and Latin America; the monetary endowments of these prizes have been invested in the trust fund of the ACG or another of his conservation's projects in Costa Rica. Prizes and distinctions garnered by Janzen include:

See also

Publications

The following is a selection of Janzen's publications that are not otherwise listed.

External links

Notes and References

  1. Web site: Prof. Daniel H. Janzen Interview Summary . Blue Planet Prize: A better future for the planet Earth . November 2, 2019.
  2. News: Mrs. Floyd Janzen . November 2, 2019 . The Greenville News. Greenville, South Carolina . May 8, 1980. 78.
  3. Changes Name. The Survey . May 1937 . Washington, D.C.. 13. 3–4 . 99 .
  4. Book: Becher . Anne . McClure . Kyle . White Scheuering . Rachel . Willis . Julia . Janzen, Daniel H. . American environmental leaders : from colonial times to the present . 2000 . ABC-CLIO . Santa Barbara, Calif. . 426–427. 978-1-59237-119-8 .
  5. Web site: Daniel H. Janzen – Frontiers of Knowledge Laureate . Fundación BBVA . October 24, 2019 .
  6. Web site: Presentation by Tropical Biologist Dr Janzen . Penn Club of Chicago . October 17, 2019.
  7. Web site: Daniel H. Janzen Académico Correspondiente . Academia Nacional de Ciencias . October 24, 2019.
  8. Janzen, D. H. 1967. Synchronization of sexual reproduction of trees within the dry season in Central America. Evolution 21: 620-637.
  9. Alwyn H. Gentry. Flowering Phenology and Diversity in Tropical Bignoniaceae. Biotropica 6(1): 64-68 1974
  10. Book: Altieri . Miguel . Agroecology : the science of sustainable agriculture . October 13, 1995 . Westview Press . 0-8133-1718-5 . 23 . 2nd .
  11. Janzen . D. H. . Tropical Agroecosystems: These habitats are misunderstood by the temperate zones, mismanaged by the tropics . Science . December 21, 1973 . 182 . 4118 . 1212–1219 . 10.1126/science.182.4118.1212 . 17811308 . 12290280 . November 2, 2019.
  12. Pringle . Robert M. . Upgrading protected areas to conserve wild biodiversity . Nature . June 1, 2017 . 546 . 7656 . 91–99 . 10.1038/nature22902 . 28569807 . 2017Natur.546...91P . 4387383 .
  13. Kazmier, Robin (June 15, 2017). "The Parataxonomist Revolution: How a Group of Rural Costa Ricans Discovered 10,000 New Species". Comparative Media Studies: Science Writing.
  14. Davis . Tinsley H. . Profile of Daniel H. Janzen . Proceedings of the National Academy of Sciences . September 26, 2017 . 114 . 39 . 10300–10302 . 10.1073/pnas.1714623114 . 28893992 . 5625942 . free .
  15. Web site: Halloway . M. . Democratizing Taxonomy. July 29, 2008 . Conservation magazine . October 18, 2019.
  16. Hebert . P. D. N. . Penton . E. H. . Burns . J. M. . Janzen . D. H. . Hallwachs . W. . Ten species in one: DNA barcoding reveals cryptic species in the neotropical skipper butterfly Astraptes fulgerator . PNAS . 2004 . 101 . 41 . 14812–14817 . 10.1073/pnas.0406166101 . 15465915 . 522015 . 2004PNAS..10114812H . free .
  17. Web site: Koerner Lecture to examine conservation of wild biodiversity via biodiversity development . York University . March 20, 2017 . October 17, 2019.
  18. Janzen . D.H. . Hallwachs . W. . How a country can DNA barcode itself . Barcode Bulletin. IBOL . October 2, 2019 . 10.21083/ibol.v9i1.5526 . free .
  19. Wolf . G. . A Simple Plan to ID Every Creature on Earth . October 15, 2019 . Wired . September 22, 2008.
  20. Sherratt . Thomas N. . Wilkinson . David M. . Bain . Roderick S. . February 25, 2006 . Why fruits rot, seeds mold and meat spoils: A reappraisal . Ecological Modelling . 192 . 3 . 618–626 . 10.1016/j.ecolmodel.2005.07.030 . 0304-3800.
  21. Currie . David J. . 2017 . Mountain passes are higher not only in the tropics . Ecography . en . 40 . 4 . 459–460 . 10.1111/ecog.02695 . 0906-7590.
  22. Web site: Daniel H. Janzen . November 29, 2023 . scholar.google.com.
  23. Janzen . Daniel H. . 1970 . Herbivores and the Number of Tree Species in Tropical Forests . The American Naturalist . en . 104 . 940 . 501–528 . 10.1086/282687 . 0003-0147.
  24. Sheldon . Kimberly S. . Huey . Raymond B. . Kaspari . Michael . Sanders . Nathan J. . 2018 . Fifty Years of Mountain Passes: A Perspective on Dan Janzen’s Classic Article . The American Naturalist . en . 191 . 5 . 553–565 . 10.1086/697046 . 0003-0147.
  25. Janzen . Daniel H. . 1967 . Why Mountain Passes are Higher in the Tropics . The American Naturalist . en . 101 . 919 . 233–249 . 10.1086/282487 . 0003-0147.
  26. Janzen . Daniel H. . 1977 . Why Fruits Rot, Seeds Mold, and Meat Spoils . The American Naturalist . 111 . 980 . 691–713 . 0003-0147.
  27. News: Kupferschmidt . Kai . March 11, 2014 . Rotten Fruit May Be Due to Microbe Warfare . Science .
  28. Speth . John D. . Eugène . Morin . October 27, 2022 . Putrid Meat in the Tropics: It Wasn't Just For Inuit . PaleoAnthropology . en . 2022 . 2 . 10.48738/2022.iss2.114 . 1545-0031.
  29. Kane . Adam . Healy . Kevin . Ruxton . Graeme D. . February 1, 2023 . Was Allosaurus really predominantly a scavenger? . Ecological Modelling . 476 . 110247 . 10.1016/j.ecolmodel.2022.110247 . 0304-3800.
  30. Mitchell . John D. . Daly . Douglas C. . A revision of Spondias L. (Anacardiaceae) in the Neotropics . PhytoKeys . August 5, 2015 . 55 . 1–92 . 10.3897/phytokeys.55.8489 . 26312044 . 4547026 . free .
  31. Book: Janzen . Daniel H. . Wilson . EO . Peter . FM . Biodiversity . Chapter 14 Tropical Dry Forests The Most Endangered Major Tropical Ecosystem . 1988 . National Academies Press (US) . Washington (DC) . https://www.ncbi.nlm.nih.gov/books/NBK219281/.
  32. Burgos . Ana . Maass . J.Manuel . Vegetation change associated with land-use in tropical dry forest areas of Western Mexico . Agriculture, Ecosystems & Environment . December 2004 . 104 . 3 . 475–481 . 10.1016/j.agee.2004.01.038 .
  33. Web site: ACG Biodiversity . Guanacaste Dry Forest Conservation Fund . October 24, 2019.
  34. Gomiero . Tiziano . Soil Degradation, Land Scarcity and Food Security: Reviewing a Complex Challenge . Sustainability . March 18, 2016 . 8 . 3 . 281 . 10.3390/su8030281 . free .
  35. Book: Costanza . Robert . Cumberland . John . Daly . Herman . Goodland . Robert . Norgaard . Richard . An Introduction to ecological economics . 1997 . St. Lucie Press . 1-884015-72-7 . registration .
  36. van den Bergh . Jeroen C. J. M. . Evolutionary thinking in environmental economics . Journal of Evolutionary Economics . February 14, 2007 . 17 . 5 . 521–549 . 10.1007/s00191-006-0054-0. free .
  37. Janzen . Daniel H. . Costa Rica's Area de Conservación Guanacaste: A long march to survival through non-damaging biodevelopment . Biodiversity . May 2000 . 1 . 2 . 7–20 . 10.1080/14888386.2000.9712501 . 129440404 .
  38. Book: Derroire . Géraldine . Secondary succession in tropical dry forests drivers and mechanisms of forest regeneration Secondary succession in tropical dry forests. (Dissertation) . 2016 . Sveriges lantbruksuniv Acta Universitatis Agriculturae Sueciae, 1652-6880 . Alnarp . 978-91-576-8634-3 .
  39. Book: Singer . F. D. . Ecology in Action. Chapter 18: Dan Janzen and Winnie Hallwachs: Community Interactions and Tropical Restoration through Biodiversity Conservation . 2016 . Cambridge University Press . 978-1-107-11537-8 . https://books.google.com/books?id=9mSSCwAAQBAJ&pg=PA467 . October 18, 2019.
  40. Cruz . R. E. . Blanco Segura . R. . Developing the Bioliteracy of School Children for 24 Years: A Fundamental Tool for Ecological Restoration and Conservation in Perpetuity of the Área de Conservación Guanacaste, Costa Rica . Ecological Restoration . 2010 . 28 . 2 . 193–198 . October 18, 2019. 10.3368/er.28.2.193 . 219193472 .
  41. Web site: Kazmier . Robin . The Parataxonomist Revolution: How a Group of Rural Costa Ricans Discovered 10,000 New Species . Comparative Media Studies: Science Writing . June 15, 2017 .
  42. Web site: The Crafoord Prize 1984 – in ecology . The Crafoord Prize . October 24, 2019.
  43. News: Fishman . Margie . Bio Prof Janzen garners 'Japanese Nobel Prize' for conservation work . October 24, 2019 . The Daily Pennsylvanian . September 22, 1997.
  44. Web site: Berkeley Citation – Past Recipients . Berkeley Awards . October 24, 2019.
  45. Web site: Meet the 1989 MacArthur Fellows . MacArthur Foundation . October 24, 2019.
  46. June 2007. The Four Awards Bestowed by The Academy of Natural Sciences and Their Recipients. Proceedings of the Academy of Natural Sciences of Philadelphia. The Academy of Natural Sciences of Philadelphia. 156. 1. 403–404. 10.1635/0097-3157(2007)156[403:TFABBT]2.0.CO;2. 198160356 .
  47. News: Founders' Council Award to Daniel H. Janzen, Ecologist . October 24, 2019 . In the field : the bulletin of the Field Museum of Natural History . 2. 62. 2 . Field Museum of Natural History . 1991.
  48. Web site: Daniel H. Janzen . National Academy of Sciences . October 24, 2019.
  49. Book: Allen . William . Green Phoenix: Restoring the Tropical Forests of Guanacaste . 2001 . Oxford University Press . 978-0-19-516177-9 . 132–136.
  50. Web site: The ISCE Silver Medal Award . International Society of Chemical Ecology . October 24, 2019.
  51. Web site: Past SCB Award Recipients . Society for Conservation Biology . October 24, 2019.
  52. Web site: University Awards and Honors . University of Michigan . October 24, 2019 . February 15, 2018 . https://web.archive.org/web/20180215024349/http://uawards.dl.umn.edu/honorary-degree/honorary-degree-recipients . dead .
  53. Web site: Chairs in SAS: A Baker's Dozen . University of Pennsylvania . October 24, 2019.
  54. Web site: Daniel Hunt Janzen . Kyoto Prize . October 24, 2019.
  55. Web site: Albert Einstein World Award of Science 2002 . August 13, 2013 . dead . https://web.archive.org/web/20140607005538/http://www.consejoculturalmundial.org/winners-science-danieljanzen.php . June 7, 2014 .
  56. Web site: Honorary Fellow, ATBC 2002, Dr. Daniel H. Janzen . Association for Tropical Biology and Conservation . October 24, 2019.
  57. Web site: Design & Artistic Merit Category: National Outdoor Book Awards (NOBA) . The Guide to Outdoor Literature . October 17, 2019.
  58. Web site: Daniel Janzen honoured with BBVA Foundation award . July 16, 2019 . International Barcode of Life . 2012.
  59. News: Baillie . Katherine Unger . Penn Biologist Daniel Janzen Honored With BBVA Foundation Frontiers of Knowledge Award . July 16, 2019 . Penn Today . February 7, 2012.
  60. Web site: Wege Foundation announces $5 million grant to help protect northwestern Costa Rica . Environmental Grantmakers Association . July 16, 2019. December 18, 2013.
  61. Web site: 2019 Blue Planet Prize: Announcement of Prize Winners . The Asami Glass Foundation. July 10, 2019 . October 17, 2019.

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