Study found widespread mislabeling and misidentification of plant specimens.
Too few taxonomic revisions over the years, and a doubling of specimen collections and herbaria could have resulted in these errors, researchers write.
Study suggests use of remotely accessible digitized specimens, instead of traditional practice of expert taxonomists visiting herbaria to name specimens.
Most of us expect museum specimens to be accurately labelled and meticulously catalogued. But up to half of the world’s natural history specimens could have wrong names, according to a new study published in Current Biology. And this could be a big problem.
“Without accurate names on specimens, the records held in collections around the world would make no sense, as they don’t correspond to the reality outside,” Robert Scotland, co-author from the Department of Plant Sciences at Oxford, said in a statement.
To see how prevalent mislabeling and misidentification is within natural history specimens, Scotland and his colleagues from the University of Oxford and the Royal Botanic Garden Edinburgh, evaluated accuracy of specimen names at three stages, for three groups of plants.
First, they checked names given to more than 4,500 specimens of the African ginger (genus Aframomum) — flowering plants that occur in Tropical Africa and some islands of the Indian Ocean.
Typically, specimen names can change over the years as scientists learn more about the species. For the African ginger, scientists completed a detailed monograph in 2014, in which they reviewed all species — and their names — within Aframomum.
When the researchers scanned through names given to the African ginger specimens from the time they were collected, until their current names in the monograph, the team found that at least 58 percent of the specimens had been either misidentified, given an outdated name, or had been incompletely identified to the genus or family.
The team also looked at mistakes prevalent in duplicated specimens present across the world.
Plant collectors often collect more than one specimen of a single species, and send it to different museums or herbaria, where independent experts evaluate and label them.
On analyzing duplicated specimens of Dipterocarpaceae, a family of rainforest trees from Asia, the team found that 29 percent of the specimens had different names in different herbaria. And some names were completely wrong.
The team also looked through online database of nearly 50,000 specimen records of a group of plants called Ipomoea, and found that 40 percent of specimens had outdated names, 16 percent of the specimens had invalid or unrecognized names, and 11 percent of specimens had incomplete names.
Mistakes appear to be widespread in specimen labelling. And these errors could have crept in due to a number of reasons, the researchers write the paper.
The first reason, they write, is that there are “too few taxonomic revisions” over the years — such as the monograph scientists compiled for Afromomum — which means that many specimens remain wrongly or incompletely identified for decades.
The second problem, according to the authors, could be that there are too many available specimens to accurately identify. Number of collected specimens in herbaria have doubled since 1970, they write, making misidentification more likely.
The third problem is that the number of herbaria have also greatly increased, the authors write, doubling between 1957 and 2000. This means that there are “too many herbaria for a given expert to visit or request loans from”.
“Rapidly increasing numbers of specimens in increasing numbers of herbaria are not being revised because there are too few taxonomists,” the authors write.
In 2004, a study found that insect specimens suffered from a similar problem of widespread mislabeling, and incorrect or incomplete names. Since flowering plants and insects constitute majority of the recognized species on earth, Scotland and his team estimate that this problem must be rife across all groups of plants and animals.
“We think a conservative estimate is that up to half the world’s natural history specimens could be incorrectly named,” Zoë Goodwin, lead author from the University of Oxford, said in the statement.
Given the widespread inaccuracies in specimen names, the authors write that the traditional method of depending on expert taxonomists visiting to herbaria to name specimens, may no longer be reliable.
“Digitized specimens, remotely accessed and integrated into species-level taxonomy, are essential to improve the names associated with the world’s natural history collections,” they write. “Specimen data have huge potential to address global environmental problems, but the rate of increase in natural history collections across the world has greatly outpaced the ability to process, evaluate and name them correctly”.
- Goodwin ZA, Harris DJ, Filer D, Wood JRI, Scotland RW (2015) Widespread mistaken identity in tropical plant collections. Current Biology 25(22) DOI: http://dx.doi.org/10.1016/j.cub.2015.10.002