Pteridophytes (ferns, lycophytes and their allies)

Ferns and lycophytes as biodiversity indicators

Pteridophytes (ferns and lycophytes) are a widespread group of plants of around 13,000 species found in almost every habitat in the world. 

We selected 1,500 species of pteridophytes at random from a global checklist and carefully assessed the IUCN Red List status of each species. 

The IUCN Red List Index is used as an indicator to measures progress towards Aichi Target 12, one of the one of the biodiversity targets from the Convention on Biological Diversity (CBD).

Our work will help to include pteridophytes in international conservation targets as part of the IUCN Sampled Red List Index (SRLI) for Plants.

Assessing ferns and lycophytes for the IUCN Red List Index

Before our work, only 362 pteridophytes species had been assessed under IUCN Red List Criteria, of which 54% were thought to be threatened. As a result of our assessments, 972 additional pteridophyte species have now been assessed, of which only 16% were found to be threatened.

Our work shows the difference between assessing species that were already thought to be threatened, versus selecting a representative sample of species from around the world irrespective of their conservation status. It also shows the importance of selecting a representative sample to obtain a realistic estimation of the overall proportion of threatened species around the world for this taxonomic group.

Assessing Pteridophytes using Museum collections

These assessments were undertaken at the Natural History Museum using the locality details from the specimens in the Museum collections, as well as other available specimen records from online sources and published taxonomic literature, and the expertise provided by the Museum senior curator of pteridophytes, Alison Paul, and scientific experts around the world.

PhD students Mindy Syfert and Elina Aletrari studied the spatial distribution of pteridophytes that were found to be more susceptible to extinction. They used species distribution modelling to predict the species’ occurrence, and satellite imagery to calculate the extent of suitable habitat for each species.

Our research  methodology

So we can be sure how the value of the Sampled Red List Index is changing over time, a threshold of at least 900 species must be assessed into one of the non-data deficient categories of the IUCN Red List, either non-threatened (Least Concern or Near Threatened) or threatened (Vulnerable, Endangered or Critically Endangered). 

We selected 1500 species completely at random from the global checklist, which includes a large proportion (40%) of built-in redundancy to accommodate the many species that are too poorly known for us to assess them (species that are Data Deficient or cannot be evaluated). 

The distribution of each species was mapped using the recorded localities of previously collected individual specimens. Once we had this information recorded in a database, we used these data together with existing scientific studies, online tools and satellite imagery to infer threats to the survival of the species, and evaluated this information using the IUCN Red List Criteria to establish the appropriate category for each species. 

Plants Under Pressure projects