Is there anyone empirically investigating agrobiodiversity loss? Specifically I'm asking about Crop Genetic Diversity and thus not the loss of cultivars by itself or the variety of cultivated crops. Accordingly, the loss of genes (or traits) can be prevented by Ex-Situ conservation.
I found only one source empirically investigating crop genetic diversity loss and this was stating that on the gene level, there is no loss for the 8 crops investigated (Van de Wouw et al. 2010).
Then there is this famous FAO-Statement: «Since the 1900s, some 75 percent of plant genetic diversity has been lost as farmers worldwide have left their multiple local varieties and landraces for genetically uniform, high-yielding varieties.» However, I couldn't find any empirical support for this statement. And this document links to a paper about women's role for agrobiodiversity, but nothing about agro biodiversity loss.
Can anyone help?
References:
FAO (n.d.): What is happening to agrobiodiversity? Online available under: http://www.fao.org/docrep/007/y5609e/y5609e02.htm [Accessed July 5, 2013].
FAO. 1999b. Women: users, preservers and managers of agrobiodiversity. http://www.fao.org/sd/nrm/Women%20-%20Users.pdf
Van de Wouw M., Van Hintum T., Kik C., Van Treuren R., & Visser B. (2010): Genetic diversity trends in twentieth century crop cultivars: a meta analysis. In: Theoretical and applied genetics., vol. 120:6, 1241–52.
Thank you a lot for the links. So there basically is an agreement, that there was no quantified loss in grop genetic resources...
I guess much of the rumor about grop genetic erosion comes from the fact, that they were replaced with newer varieties. Like if you look on the road, there was a massive loss of Ford's Model T since 1940's (or so). But no one would claim a loss of car diversity since then. Especially as the functionality of the Ford-T got preserved, improved and extended in the newer cars.
However, I guess a loss in grop genetic resources happened in the first half of the 19th century, which is probably hard to prove.
I've also published a paper which goes somewhat more into the background of genetic erosion and the problems of measuring it: "Genetic erosion in crops: concept, research results and challenges". I concluded that there probably is a reduction in genetic diversity when landraces are replaced with modern cultivars, but no further reduction after that.
Do you think, this famous 75% of crop genetic diversity loss might origin in Hammer et al. (1996, 2005)? They defined genetic erosion as the difference of landraces found in field studies:
-> Italy: 72% fewer Landraces
-> Albania: 73% fewer Landraces
Reference
Hammer K., Knüpffer H., Xhuveli L., & Perrino P. (1996): Estimating genetic erosion in landraces - two case studies. In: Genetic Resources and Crop Evolution, vol. 43, 329–336.
Hammer K., & Laghetti G. (2005): Genetic Erosion – Examples from Italy. In: Genetic Resources and Crop Evolution, vol. 52:5, 629–634.
Maybe it originates from the first paper, the Italy example is from 2005, and a bit late then for the FAO statement. Hammer and his research group take a very narrow view on genetic erosion: completely ignoring the fact the system is dynamic. Throughout history (land) races have disappeared and replaced with other landraces or (nowadays) modern cultivars. The focus on what has been lost and ignoring what has been gained does not really reflect what has been going on with agricultural diversity
B.R.: "Is there anyone empirically investigating agrobiodiversity loss?"
yes (and not only empirically)
that could be a good subject for a project in the frame of the program launched by your country and mine
My guess is that there is a typo, and the reference should have been to:
FAO. 1999a. Agricultural Biodiversity, Multifunctional Character of Agriculture and Land Conference, Background Paper 1. Maastricht, Netherlands. September 1999.
I have no access to this paper, so cannot test my hypothesis.
[I came here while on a similar quest, which includes GM crops too]
Thanks for the answer
I guess that references to the report available here:
http://www.fao.org/docrep/x2775e/x2775e00.HTM
However, skimming through it I don't see any numbers there quantifying the loss of PGR. Even though they do list some measures to conserve PGR.
I guess the source publication for the 75% statement would be:
FAO (1993): "plant genetic resources". In: Development Education Exchange Papers (DEEP), September 1993.
However, I couldn't find it. So I still don't know how they came to that conclusion.
I got aware by stumbling upon this: «It has been estimated, that 75% of genetic diversity of cultivated plants has been lost across the globe since the beginning of the 20th century.» Found in the book:
Christinck A., & Padmanabhan M. (eds.) (2013): Cultivate diversity! A handbook on transdisciplinary approaches to agrobiodiversity research. Margraf: Weikersheim.
Which references this statement to the following publication:
Shand H. (1997): Human nature: Agricultural biodiversity and farm-based food security. RAFI (Rural Advancement Foundation International).
Which then references to the above mentioned FAO publication.
I've written about this a number of time on the Agricultural Biodiversity Weblog: http://agro.biodiver.se/?s=75%25
I am here for the same quest "how was this 75% loss in genetic diversity measured? and much more importantly has there been any updates on this front? Are still losing plant genetic diversity? or some are lost and replaced by new ones? Is it still okay to quote this famous Hammer et all 1999 paper? is this credible information?
Hello! I'm doing a deep dive on this question too, and wanted to mention a few things: 1) Hammer et al. 1996 can't be the source, as I've found a doc as early as 1993 from the UK House of commons stating "The UN FAO recently warned that, from an agricultural point of view, the world had lost nearly three-quarters of the genetic diversity of plants grown since the beginning of the century," ( https://commonslibrary.parliament.uk/research-briefings/rp93-94/ ). At this point it appears that the statement is likely a gross extrapolation of two statements made in Fowler and Mooney (1991) about the potential loss of varieties in Europe due to the narrowing of a list of varieties allowed to be cultivated (in the 1970s). Fowler and Mooney learned this from Erna Bennett, who was at FAO from 1967 to 1982 - "“Many varieties- indeed up to three-quarters of all those presently grown in Europe, according to Erna Bennett- will become extinct within ten years!” (pp. 85-86). So, in a roundabout sense, it does seem that FAO is the source... Fowler and Mooney never intended for the statement to be generalized and tried to inform about this in the 1990s but the narrative was stronger than the rebuttal! I'm (along with Luigi above) writing a bit of this history up for publication in a forthcoming review, which assesses more than 200 papers on the subject. Hopefully this will be of interest to you all. thanks.
Hello Beni
one study that comes to mind was done by Stef de Haan on peruvian potatoes in the context of his PhD. Stef may want to correct me if I got it wrong, but I think one of his objectives was to assess possible allelic loss over time in local potato varieties grown across villages in the Peruvian Andes. However he found no loss of genetic diversity over a 25-year period.
check:
de Haan S, Núez J, Bonierbale M, Ghislain M (2009) Species, morphological and molecular diversity of Andean potatoes in Huancavelica, central Peru. In: de Haan S (ed) Potato diversity at height: multiple dimensions of farmer-driven in-situ conservation in the Andes, PhD thesis, Wageningen University, The Netherlands, pp 35–58
and related:
Article A Simple Sequence Repeat (SSR) Marker Comparison of a Large ...
cheers Evert
I believe that the lack of baseline data on the existence of varieties/genotypes and crops/species is fundamental constraint that we have to obtain emperical data on genetic erosion. We should do something about that in a systematic way!
Jan Engels
I've written and reported in my study on Ahipa or Andean Yam Bean (Pachyrhizus ahipa) at the in-situ level. Albeit the nutritional and industrial research highlight the benefit of this Andean Root, but farmers are shifting to more rentable crops and less farming labor.
Rodríguez, J.P., Ørting, B., Andreasen, C. et al. Trends and drivers of on-farm conservation of the root legume ahipa (Pachyrhizus ahipa) in Bolivia over the period 1994/96–2012. Genet Resour Crop Evol 65, 449–469 (2018). https://doi.org/10.1007/s10722-017-0544-y
Interesting to read your question Beni. Many people are questioning the FAO statement about 75% loss of genetic diversity. Although, the scale at which we consider loss of genetic diversity can be many (spatial, species, population etc.) there are surveys that indicate loss of diversity based on varieties farmers grow. In 2018, I conducted a survey (over 400 households) in 4 villages in southeastern highlands of Ethiopia where continuous monoculture cropping of bread wheat displaced durum wheat since late 1960s. Compared to 30 different local varieties of durum wheat grown in the area before introduction of green revolution varieties in the 1960s ( http://publication.eiar.gov.et:8080/xmlui/handle/123456789/2800 ), I encountered only three wheat varieties. It is possible that more varieties can be found if the survey covered wider area and larger number of HHs. Still the trend shows replacement of durum wheat with bread wheat in the area. Other studies show similar trend: 1) https://doi.org/10.1007/s10722-005-1145-8 ; https://doi.org/10.1007/s10722-006-0016-2.
Very interesting topic indeed. Last year we tried to generate few data on loss of crop/genotype diversity, as a part of the study (https://www.nepjol.info/index.php/janr/article/view/32482). Our latest article states: For Nepal, an estimated loss of agrobiodiversity is 40%, however, farmers have reported up to 100% loss of AGRs in some areas for a particular species (https://www.nepjol.info/index.php/JNARC/article/view/28111). Many times we had debate about this figure and looking for improved methodology for collecting empirical evidences. Is there anyone who can work to improve methodology for collecting empirical evidences on estimating loss of agrobiodiversity?....
In my opinion what matters is whether crop evolution by farmers continues or not, since this is the process that maintains and contributes to generate adaptive genetic variation. As in all evolutionary processes there will be loss, but also new variation should appear. So specific varieties or alleles may disappear, but as long as the evolutionary process continues by many farmers across different environments, variation will continue to exist and change. Given this approach what we should be worry is that farmers no longer save and share the seeds of their crop populations, that the size of the effective populations decreases and that there is a reduction of the environments and conditions under which these crop populations are grown. Scale matters because evolution is a numbers' game.
Mauricio Bellon's contribution is an important and also in my opinion a correct one. Whereas we might not have the quantitative data to 'demonstrate' the contributions of farmers worlswide, we do know that they were the ones that started the process of cultivating wild species, domesticating these, diffusing the domesticated 'packages' (animals and plants), along with weeds and in some cases with their wild relatives and thus, converting the world into what we have become since 10.000 and more years. Whereas breeding companies and genebanks have been established to take over certain aspects of the farmers' evolutionary 'responsibilities', we need to be able to lean on a much broader process in order to allow the 'numbers' (as Mauricio puts it) to play the game and to ensure sufficient and adequate genetic diversity to be maintained in the production systems worldwide. Money is not the solution!!
Interesting discussion, would be good to get more evidence on this to underpin the trends of ongoing loss of agrobiodiversity that are repeatedly be reported such as more recently by Pilling et al. in Nature Food in 2020 (http://www.fao.org/cgrfa/resources/news/detail-events/en/c/1263544/). To understand trends in use of agrobiodiversity and its implications for sustainable food systems it might be worthwhile to distinguish trends in different user groups. For vegetables such as tomato there might be opposite trends in use and development of diversity by farmers and by seed companies. Some studies confirm a decline in the use and maintenance of local tomato varieties (Article The Deterioration of Morocco’s Vegetable Crop Genetic Divers...
). At the same time, the genetic variation in commercial tomato varieties may be increasing because seed companies use a wide range of tomato diversity in breeding including crop wild relatives.. Even so, this probably does not compensate for the loss of genetic variation and the evolutionary processes in farmer fields. Finally, there are new trends such as the use of tomato diversity by urban farmers who can create new ways of seed use, exchange, and crop evolution (https://greencitygrowers.com/blog/know-your-tomatoes/). All together a dynamic and complex system of crop use and evolution.
We just published an article on trends of crop varietal diversity in Asia and Africa. This may be of interest to you...
Article Trends in Varietal Diversity of Main Staple Crops in Asia an...
One question is whether you want to keep genes or genotypes. It is evident that landraces have been lost for many reasons all around the world. I agree that keeping sexual forms of the landraces as ex situ germplasm can be a cost-effective way of preserving the genes. Genes involved in positive agronomic traits are often in high frequencies so chances of losing them are very low. Preserving landraces (genotypes) is more complicated because the limited capacity of genebanks, the large number of native landraces, the restrictions of getting them transferred, etc. On the question of agrodiversity lost-- in my experience one very serious problem is the shrinking of native community populations, we can see more and more that young people are moving away from their communities so there are less farmers and an aging population to do the work that include native cultivar preservation.
Article Farmers’ Perception about the Use of Sorghum (Sorghum bicolo...
Dear colleagues, thank you for this continued thread of most interesting comments. Back to the "75% of crop diversity has been lost in the 20th Century" quote, I've continued to work hard at figuring out the original time this was said in publication (likely by FAO or perhaps IBPGR), and also the origin of the data underlying that quote. I've been interviewing/corresponding with many of the experts from the time (likely around 1985-1995). But both answers are still pretty much a mystery. The first published sighting I have found is an FAO report from 1993 prepared for Earth Day, called Harvesting Nature's Diversity (http://www.fao.org/3/v1430e/V1430E00.htm) and written, interestingly, by Hope Shands of RAFI (now ETC Group), i.e. where Pat Mooney and Cary Fowler were affiliated at that time. The quote appears twice in the document, but with no citation other than "FAO estimates...".
I write to ask this group if anyone possibly knows of any earlier publication with this quote in it? Feel free to be in direct touch if you like [email protected] Thanks!
Hello Collin,
The closest to the data I got on a similar search was p. 52 from Pistorius (1997) where he mentioned the examples from wheat in India and Pakistan and Turkey, and rice in Sri Lanka that the Panel of Experts referred to during FAO/IBP Technical Conferences on Crop Genetic Resources in 1967 and 1973, although I couldn’t get to the sources of those estimates.
If something else could be useful, Harlan (1975) documented Harlan and Martini (1936) as the earliest mention of a potential issue with genetic erosion, in this case in barley. This was stated as an observation though and figures were not mentioned.
-Harlan, J. R., and M. L. Martini. 1936. Problems and results in barley breeding. In USDA Yearbook of Agriculture, 303–346. Washing- ton D.C.: Government Printing Office: United States Department of Agriculture.
-Harlan, J. R. 1975. Our Vanishing Genetic Resources. Science 188 (4188): 618–621.
-Pistorius, R. 1997. Scientists, plants and politics: A history of the plant genetic resources movement. Rome, Italy: IPGRI.
Thanks so much Denisse. I've reviewed the Technical conference papers and the quote isn't there; also not in Harlan and Martini 1936 (of course), nor Harlan 1975... still on the hunt...gracias!
Hola Colin, the Conference papers were my last hope. Looking forward to see what you find in the end.
i can asume that this papers can help you.Article The Effect of Selection on Genetic Variability
Article The Effect of Selection on Genetic Variability
Dear colleagues, I’m thrilled to get to announce that we have finally published a major review of crop genetic erosion, which is open access here: https://doi.org/10.1111/nph.17733. Thank you for this thread, which was useful toward this effort. Regarding the mysterious origins of the “75% of crop diversity lost in the past century”, please see Box 1 in the article. This represents our ongoing work to clarify the origin of this narrative. Spoiler – we still aren’t sure of the origin, but we have some good ideas about where it may have come from. Thank you again. Please pass this paper around.