Pteridophytes (ferns, lycophytes and their allies)

A fern growing on a mossy rock

A fern growing in Kilimanjaro National park, image by Ana Claudia Araújo 

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.

Plants Under Pressure

Find out about the Plants Under Pressure programme monitoring the state of the plant world.

Museum staff

Project summary

  • Focus: Assessing threats to plants across the world

What’s next?

Our selected species will now be reassessed to reveal how the overall status of pteridophytes as a group is changing over time.

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. 

Pteridophyte species assessed under IUCN Red List Criteria

A bar chat for pteridophytes assessed under the IUCN Red List Criteria

Only 362 pteridophyte species had previously been assessed under IUCN Red List Criteria by 2016, and of these 54% were thought to be threatened with extinction (left hand column). An additional 972 pteridophyte species selected at random have now been assessed for the IUCN Sampled Red List Index (SRLI) for Plants, and of these only 16% were found to be threatened (right-hand column). CR (Critically Endangered), EN (Endangered) and VU (Vulnerable) are the three threatened categories, the other categories are Near Threatened (NT), Least Concern (LC) and Data Deficient (DD).

Plants Under Pressure projects


Brummitt, N.A., E. Aletrari, M. Syfert & M. Mulligan, 2016. Where are threatened ferns found? Global conservation priorities for pteridophytes. Journal of Systematics and Evolution 54(6): 604–616. doi: 10.1111/jse.12224

Syfert, M.M., L. Joppa, M.J. Smith, D.A. Coomes, S.P. Bachman & N.A. Brummitt, 2014. Using species distribution models to inform IUCN Red List assessments. Biological Conservation 177: 174–184


Plants Under Pressure

Assessing threats to plants and monitoring the state of the plant world.

Bryophytes (mosses, liverworts and hornworts)

We have assessed 1021 species of bryophytes from around the world using the IUCN Red List Criteria, a ten-fold increase.

Hotspots of plant diversity

Expeditions to areas of high plant diversity help us to ensure that our IUCN Red List assessments are accurate.

Comparing plant diversity indicators

Can we detect small-scale changes to biodiversity?

Simulating plant diversity change

How might plant diversity respond to changing situations in the future?

Essential Biodiversity Variables

How should we study the full extent of change to biodiversity?