Category: Genetic erosion

A posting from the good people at Bioplan ((A mailing list on biodiversity policy issues set up and maintained by the UNDP and UNEP.)) forwarded to me by my friend Mary Taylor has just alerted me to an article over at Mongabay which would probably have eluded me as I’m on the road at the moment and not checking the feedreader very systematically. So thanks, Mary.

The post is about the “shifting baselines” theory, apparently an influential concept in conservation thinking during the past decade and more but one that alas I hadn’t come across. It proposes that…

…due to short life-spans and faulty memories, humans have a poor conception of how much of the natural world has been degraded by our actions, because our ‘baseline’ shifts with every generation, and sometimes even in an individual. In essence, what we see as pristine nature would be seen by our ancestors as hopelessly degraded, and what we see as degraded our children will view as ‘natural’.

And if people can’t register the loss, how can conservation be made important to them?

I’ll leave you to read the details of the paper at Mongabay. It’s about the perception of changes in the local bird fauna among 50 rural Yorkshire villagers, compared to the “reality” revealed by the results of regular ornithological surveys. Suffice it to say that the authors found evidence of both “generational amnesia” (when people fail to pass knowledge down from generation to generation) and “personal amnesia” (when people forget how things used to be earlier in their lives).

Is this relevant for studies of genetic erosion in crops? For plants, including crops, there is a pretty good way of documenting changes in distribution, abundance and even genetic diversity, and that’s by comparison of the present situation with herbarium specimens and genebank samples. And old seed catalogues have also been scoured for evidence of loss of varieties of fruits and vegetables in Europe and the United States. I’ve suggested myself in the past that these are all valid, complementary approaches to the estimation of genetic erosion, though they all have their shortcomings. But I can’t think off the top of my head of a study which has combined making historical comparisons with asking people about how many varieties of a particular crop they used to grow, to gauge the accuracy of their recollections, though my own recollection of the literature may be faulty too! It seems to me that farmers are more likely to accurately recollect the crop varieties they used to grow than almost anything else, including the birds that fly around them, especially if you get a group of them together to discuss the issue, but it would be an interesting thing to test.

One of the authors of the paper does mention specimens in passing in his Mongabay interview.

“If the issue is with personal amnesia, just talking to people and triggering their memories about how things were, perhaps with the aid of props like photos or old specimens, will help them to ensure that their perceptions of change are accurate,” Milner-Gulland says.

That’s as part of a discussion of the “increasingly creative” ways of “finding data regarding past conditions that may no longer be remembered” that certainly has relevance for crops.

“One author (Julian Caldecott) used school meal records from remote village schools to reconstruct wild pig migrations in Borneo. There are many authors now using historical records and archeological remains, for example in charting the changes in fish stock compositions in the North Sea over thousands of years. Other people use contemporary accounts from eye-witnesses, while still others use scientific methods like pollen analysis, which can go back far beyond written accounts.” Milner-Gulland says, adding that “the important issues involve recognizing and accounting for sources of bias in the records that you use.”

And that goes for the knowledge of farmers too.