|Scientific Name:||Mammillaria duwei|
|Species Authority:||Rogoz. & P.J.Braun|
|Taxonomic Source(s):||Hunt, D., Taylor, N. and Charles, G. (compilers and editors). 2006. The New Cactus Lexicon. dh Books, Milborne Port, UK.|
|Taxonomic Notes:||Considered a synonym of M. crinita by Anderson (2001) and by the assessors (Fitz Maurice 2002). Considered a provisional species by Hunt (1999) and a subspecies of M. nana by Pilbeam (1999).|
|Red List Category & Criteria:||Critically Endangered B1ab(v) ver 3.1|
|Assessor(s):||Fitz Maurice, B & Fitz Maurice, W.A.|
|Reviewer(s):||Superina, M., Goettsch, B.K. & Chanson, J.S.|
Mammillaria duwei is listed as Critically Endangered due to a very limited range (extent of occurrence and area of occupancy 35 km2), it is known from only one location, has a small population size, and there is a continuing decline due to overcollection and development. Estimates of population size and range are, however, dubious for this taxon as the description does not reliably differentiate it from M. crinita.
|Previously published Red List assessments:||
|Range Description:||This species is found at one location northeast of the city of Guanajuato, Mexico, at 1,800 to 2,000 m asl.|
|Estimated area of occupancy (AOO) - km2:||35|
|Number of Locations:||1|
|Lower elevation limit (metres):||1800|
|Upper elevation limit (metres):||2000|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The southernmost of the two known subpopulations of this species has declined as a result of collecting over the past 15 years. Currently the total population is estimated at approximately 500 individuals.|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||This species is found on volcanic rock in xerophyllous scrub.|
|Use and Trade:||This species is illegally collected for sale as an ornamental in local markets.|
|Major Threat(s):||This species is threatened by illegal collection and land development.|
This cactus is listed on CITES Appendix II, but enforcement of the laws in the countries of destination is required. Plants from the type locality have been widely propagated, although collecting by individuals and tour groups continues.
This species is legally protected in Mexico by the national list of species at risk of extinction, NOM-059-SEMARNAT-2010, where it is listed under category “subject to special protection” (Pr; SEMARNAT 2010).
|Citation:||Fitz Maurice, B & Fitz Maurice, W.A. 2013. Mammillaria duwei. The IUCN Red List of Threatened Species 2013: e.T40832A2935278. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T40832A2935278.en . Downloaded on 10 October 2015.|
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