by Hayley Dunning, Science Web Editor

A species of nightshade  thought to be restricted to one area of Peru has been found in 17 other  locations with the aid of habitat modelling.

Museum botanists Dr Tiina Särkinen (now at the Royal Botanic Garden Edinburgh) and Dr Sandra Knapp discovered the new species of nightshade, named this week as Solanum pseudoamericanum,  in 2012 in the Andes. When they first found it, they thought this  species only occurred in two river valleys in southern Peru. By using a  method known as species distribution modelling, they predicted other  regions of Peru where the plant might also be found, based on the  environmental conditions at the original collection sites.

An example of the newly discovered Solanum pseudoamericanum, collected on 7 March 2012.

The flowers are on the left and the berries on the right.

A  collecting field trip to northern Peru the following year uncovered the  nightshade in 17 new locations predicted by the model. The success of  the project proves the method of species distribution modelling can work  in complex climatic regions such as the Andes, where there is an  abundance of undiscovered species and data coverage is generally poor.

Mapping species

Species  distribution modelling uses climatic data to help map the range of a  new species, speeding up the process of cataloguing it worldwide and  providing a way to accurately predict where that species might be found  again.

The approach may be particularly useful when dealing with critically endangered species, where there is an urgent need to find and conserve remaining populations.

The work is part of a larger project to map the distribution patterns of all the endemic Solanaceae species in Peru, and to look for components of rarity; what sorts of  things make plant species rare. With this information, researchers hope  to be able to better describe, and then conserve, plant diversity in  Peru.

Hidden diversity

Species  distribution modelling has been used successfully for vertebrates  before, but has not been widely tested in plants. Dr Knapp belives this  may be because collecting plants is seen as reasonably straightforward,  but this case study suggests that it is not always true.

Solanum pseudoamericanum was not originally collected because it looks a lot like a common weed.  ‘Collecting is extremely biased, and this raises the question of how we  deal with absences,’ Knapp said. The new species represents a category  of ‘hidden diversity’, where new discoveries can be obscured by their  physical similarity to known, common species.

Open data

The research, and all its associated geographical and specimen data, is published this week in the open-access journal PhytoKeys.  By publishing the results and original specimens as open data, said  Knapp, large specimen datasets can be combined by other researchers  globally to produce more general analyses of diversity.

• To follow the adventures of the Solanaceae seekers, read the Museum blog Nightshades: the paradoxical plants.
• For more information about nightshades and their global distribtuion, visit the Solanaceae Source scratchpad.